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CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a Divisional of U.S. patent application Ser. No. 09/719,153, filed Mar. 16, 2001, which is a 371 of International Patent Application No. PCT/FR99/01375, filed Jun. 10, 1999, and claims priority to French Patent Application No. 98/07276, filed Jun. 10, 1998. The entire contents of U.S. patent application Ser. No. 09/719,153 is included herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to substrates provided with a photocatalytic coating, and to the process for producing such a coating and to its various applications.
It relates more particularly to coatings comprising semi-conducting materials based on metal oxide, in particular on titanium oxide, which are capable of initiating radical reactions under the effect of radiation of appropriate wavelength, resulting in the oxidation of organic products. These coatings thus make it possible to confer novel functionalities on the materials which they cover, in particular dirt-repellent, fungicidal, bactericidal, algicidal or odour-controlling properties, optionally in combination with hydrophilic or anti-condensation properties, and the like.
2. Discussion of the Background
Highly diverse substrates have to date been envisaged, in particular construction materials used in the field of construction or vehicles (windows, facing, cladding or roofing materials, and the like) or materials used in purification processes.
International Patent Applications WO97/10186 and WO97/10185 have thus made known coatings comprising anatase crystallized TiO 2 with photocatalytic properties, coatings obtained from the thermal decomposition of appropriate organometallic precursors and/or from “precrystallized” TiO 2 particles, suited in particular to deposition as a thin layer on glass in order to preserve its optical quality.
Patent Application EP-A-0,306,301 has also made known the use of photocatalytic TiO 2 on fibrous materials used to purify the air, the deposition of the TiO 2 being carried out by a process of sol-gel type.
SUMMARY OF THE INVENTION
The aim of the invention is then the improvement of these photocatalytic coatings, being targeted in particular at improving their behaviour on any type of substrate and in particular providing them with better adhesion and better durability, particularly on substrates exhibiting characteristics of surface roughness of porosity.
The subject-matter of the invention is first of all a substrate comprising a fibrous material which is provided, over at least a portion of its surface and/or within its thickness, with a coating with photocatalytic properties comprising a semi-conducting material with photocatalytic properties of the oxide or sulphide type in combination with a promoter of adhesion to the said fibrous material.
The semi-conducting material “active” with respect to photocatalysis can be, according to the invention, based on at least partially crystallized metal oxide, for example zinc oxide, tin oxide or tungsten oxide. The preferred example according to the invention relates to titanium oxide at least partially crystallized in anatase form, which is the crystalline phase which confers on TiO 2 its photocatalytic properties. It can also relate to semi-conductors belonging to the family of the sulphides, also at least partially crystallized, such as zinc sulphide or boron sulphide. (In the continuation of the text, for greater simplicity, mention will be made of titanium oxide, it being understood that the information given will be just as valid for the other semi-conducting materials mentioned above).
The term “fibrous material” is understood to mean, within the meaning of the invention, any material comprising fibres, in particular mineral fibres, more particularly organized fibres made of glass or rock mineral wool, of the type of those used in thermal/sound insulation or to constitute soilless culture substrates. This term “fibrous material” also includes fibres/filaments organized as strands, of the type of the strands used in reinforcement, in particular made of glass.
These base fibrous materials are subsequently incorporated in a “substrate”, within the meaning of the invention, in various forms: it can relate to felts, mats, webs, “moulds” intended for the insulation of pipes, made of mineral wool, textile strands assembled as fabrics, or non-woven web, made of substrates of paper type, and the like.
A photocatalytic coating makes it possible to confer highly advantageous novel functionalities on these known substrates. Thus, the felts/mats of mineral wool mainly used in insulation can be treated only superficially, only on one of their faces, for example, or on each of their faces, and can acquire a dirt-repellent/odour-controlling function on at least one of their treated faces (the visible face and/or the hidden face) in false ceiling structures of buildings, in antinoise screens alongside roads or railways, and the like, the condition laid down being that the photocatalytic coating is accessible to a natural or artificial light source. Still in the field of insulation, the “moulds” can also be treated on the inside and/or outside or over their entire thickness, for example, in order to confer on them a dirt-repellent and/or bactericidal or fungicidal function. In the form of mats or of moulds, the substrates treated according to the invention can advantageously be positioned around outlet conduits in any ventilation or air-conditioning system but also by being positioned inside these conduits, these devices being veritable breeding grounds for bacteria, the condition being that it is necessary to provide means for the photocatalytic coating to be exposed to sufficient ultraviolet radiation to be effective: on a visible external face, natural illumination may be sufficient. If not, the substrates have to be combined with artificial illuminating means of the halogen lamp or fluorescent tube type.
Another application relates to any system for reflecting and/or scattering natural light or light originating from artificial illuminating means, such as lampshades or curtains, when the substrate is, for example, in the web form.
The other main application, apart from thermal or sound insulation, of the substrates treated according to the invention relates to the filtration or the purification of fluids.
It can relate to any filter used in the filtration of gases, in particular of air, of paper web or filter paper type, used, for example, in the ventilation/air-conditioning systems for dwellings mentioned above or for industrial premises, vehicles or laboratory rooms with a controlled level of dust, of the “clean” room type.
The term “filter” covers two notions within the meaning of the invention, both the notion of true filtration, where particles are separated mechanically from the gas carrying them, and the notion of diffuser, in particular of odour-controlling diffuser, where the gas to be treated is not necessarily forced to pass through the photocatalytic substrate, where it can in particular simply be brought into contact with the latter, without retaining the suspended particles.
Mention may be made of many other applications of the gas “filters” according to the invention: they can also be used to purify any type of industrial gaseous effluent or any atmosphere of a given public place or building (as odour-controlling diffuser in the underground, for example). They can in particular make it possible to reduce the “VOC” (volatile organic compounds) level of a given gas stream or of a given atmosphere.
The filters, surface-treated or treated throughout their thickness, can become much more effective and much more durable; this is because the treatment according to the invention gives them the ability not only to remove microorganisms but also to decompose organic residues of fatty type, for example, particles which gradually block the filter. With the invention, these filters therefore have a longer lifetime. In addition, they have an odour-controlling function.
It can also relate to filters for liquids.
The liquid filters according to the invention have numerous applications: they can be used for the recycling of wastewater or for the recycling of water from systems for the irrigation of soilless culture substrates (for disinfecting the water). They can also fulfil a function of depollution, in particular depollution of soils, or a function of reprocessing/depolluting industrial liquid effluents.
The advantage of treating all these fibrous substrates according to the present invention has been seen. However, to furnish term with a photocatalytic coating was not, initially, very easy. This was because the question arose of the method of deposition of the coating on a substrate which is generally non-smooth, non-flat and of rough and porous type, as well as the question of the durability of this coating.
The solution of the invention consisted in adjusting the way in which it was applied to the substrate, namely superficially or throughout its thickness, according to the applications targeted as a function of requirements, and in rendering the anatase TiO 2 of the coating, which is responsible for the photocatalytic performance, integral with the fibrous material via an appropriate adhesion promoter. The latter can thus act as “matrix” for the components of the coating which are “active” with respect to the photocatalysis phenomenon.
According to a first embodiment of the present invention, the titanium oxide is already at least partially precrystallized in anatase form when it is incorporated in the coating, before being deposited on the substrate. It can be introduced into the coating in the form of crystalline particles in colloidal suspension or in the form of a dry power composed of particles which are optionally more or less agglomerated with one another. This alternative form exhibits the advantage of not imposing a high specific heat treatment on the coating/substrate on which it is deposited (TiO 2 crystallizes in the anatase form generally in the vicinity of 400° C.).
According to a second embodiment of the present invention which can be combined with the first embodiment, the titanium oxide originates from the thermal decomposition of precursors, in particular of the organometallic or metal halide type, within the coating. The anatase crystallized TiO 2 can thus be manufactured “in situ” in the coating, once applied to the substrate, by providing for an ad hoc heat treatment, which must, however, be compatible with the chosen substrate and the chosen adhesion promoter.
The adhesion promoter can be single- or multicomponent, and its component or components can be organic, inorganic or organic/inorganic “hybrids”.
It can thus comprise a silicon-comprising component, in molecular form or in polymeric form, of the silane, silicone or siloxane type, for example. This is because these components exhibit a good affinity with the majority of mineral fibres, glass, rock or even ceramic, affecting the invention. It is even possible, in some cases, to speak of a kind of grafting of the crystallized TiO 2 to the inorganic fibres by this type of component.
The adhesion promoter can also comprise one or more polymers of organic type. In fact, two scenarios exist: standard organic polymers, for example of the acrylic or phenol-formaldehyde type, or the like, can be chose. In this case, there is a risk of this component being gradually decomposed by photocatalysis by the TiO 2 , at least in the surface regions of the substrate liable to be exposed to ultraviolet radiation. However, the process can in fact prove to be advantageous in some applications, by thus gradually “releasing” active TiO 2 . However, it may be preferable to avoid or slow down as far as possible this decomposition by choosing appropriate polymers, generally fluorinated polymers, which are highly resistant to photocatalytic attacks, for example of the fluorinatd acrylic polymer type, of the polytetrafluoroethylene (PTFE), poly (vinylidene fluoride) (PVDF) or tetrafluoroethylene-ethylene copolymer (ETFE) type, and the like.
One alternative is retaining an adhesion promoter based on organic polymer(s) and thwarting their decomposition by appropriate additives, in particular belonging to the family of the antioxidants (such as the product sold under the name Irganox by the company Ciba) and/or of the ultraviolet absorbers (such as the product sold under the name Tinuvin by the same company) and/or of stabilizers in the form of sterically hindered amines known under the term “hindered amine light stabilizers” or “HALS”.
The adhesive promoter can also comprise at least one metal oxide of the TiO 2 or SiO 2 type originating from the thermal decomposition of precursors of the silicon-comprising, organometallic or metal halide type within the coating. In this case, the TiO 2 or SiO 2 component is generated in situ in the coating, in particular once applied to the substrate, by an appropriate heat treatment compatible with the substrate. In the case of TiO 2 , it is not, however, necessary to envisage very high temperatures necessary for an anatase crystallization, if only an adhesion promoter function is being sought: it can perfectly well be amorphous or partially crystallized in various crystalline forms, just like SiO 2 . It is thus possible to have a coating of the amorphous metal oxide matrix type which fixes the “active” particles of crystallized photocatalytic oxide.
The adhesion promoter can also comprise at least one inorganic component chosen from aluminium phosphates and potassium or calcium aluminosilicates.
One embodiment of the invention consists in that at least one of the two essential components of the coating, namely, on the one hand, the “active” (with regard to photocatalysis) components and, on the other hand, the adhesion promoter, forms part of the binder making possible the intrinsic cohesion of the fibrous material.
This is because, if the material is glass or rock mineral wool of the insulation type, such as that produced by Isover Saint-Gobain, the latter is in numerous applications provided with a binder generally denoted under the name of size and generally applied in the liquid phase by spraying under the fiberizing devices. The solvent/dispersant is generally aqueous and it evaporates on contact with or in the vicinity of the hot fibres. The agents for sticking the fibres to one another, generally of the resin type, for example phenolic resin, such as urea-phenol-formaldehyde polymers, cure under hot conditions. One possibility then consists in adding the adhesion promoter and the “active” components to the aqueous medium of the size or even in using/adapting the components of the size in order for them to act simultaneously as binder of the fibres to one another and of promoter of fibres/“active” components adhesion.
For further details on typical sizing compositions and their method of application to fibres, reference may advantageously be made in particular to Patents EP-148,050, EP-246,952, EP-305,249, EP-369,848, EP-403,347, EP-480,778 and EP-512,908. However, it should be noted that, in specific applications, the mineral wool can be devoid of binder, for example that composed of relatively fine fibres used to prepare filter papers, as disclosed, for example, in Patents EP-0,267,092 and EP-0,430,770, or needled felts.
If the material is instead a fibrous material of reinforcing strands or textile strands type, in particular such as that manufactured by Vetrotex, the cohesiveness of the strands resulting from the assembling of individual filaments under a bushing is generally provided by application of a binder generally denoted under the term of sizing composition. Here again, it is applied in the liquid phase and comprises one or more agents “sticking together” the fibres/filaments. It is therefore possible to choose to add the “active” components and/or the adhesion promoter according to the invention to the liquid medium or to adapt its composition in order to make it act both as interfilament binder and as promoter of strands/“active” components adhesion.
For further details on sizing compositions, reference may advantageously be made in particular to Patents EP-243,275, EP-394,090, EP-635,462, EP-657,396, EP-657,395, EP-678,485, EP-761,619 and WO-98/18737.
Mention may also be made of Patent WO-98/51633, relating to the deposition of size in two steps under the fiberizing device, size in addition being capable of polymerizing at room temperature. In this case, it is possible to choose to introduce the material with photocatalytic properties either into the first sizing composition or into the second or into both.
All these sizes mentioned above are generally applied, using sizing rolls just under the bushing, to the fibrous material still in the form of individual filaments in the course of being gathered together into strands. There also exist binders, intended to ensure the cohesion of mats obtained from a blanket of glass strands, which are ejected onto continuous or non-continuous strands which have already been sized. Mention may be made, by way of example, of Patent WO-97/21861. The photocatalytic material can be incorporated in this binder, which also acts as adhesion promoter.
The sizes or binders mentioned above are either in the aqueous phase or in the non-aqueous phase. In the latter scenario, a heat treatment is generally no longer necessary to remove the water, the components chosen then being chosen so as to be able to polymerize at room temperature. In this case, the incorporation of materials with photocatalytic properties pre-existing independently of any heat treatment is favoured, such as small crystallized titanium oxide particles.
As mentioned above, the fibrous material according to the invention can therefore be organized in the web (facing, for example), felt or paper form or in various geometric forms (flat or pleated paper type sheets, for example, panel, hollow cylindrical “mould”, woven or non-woven web, and the like). The fibrous material can also be in bulk, in the form of optionally graded short fibre or flocks.
The photocatalytic coating of the invention is advantageously applied to the fibrous material so that at least a portion of the “fibres” of the said material (including the notions of fibres, of filaments and of strands) is sheathed with the coating over a thickness of at least 5 nm, in particular over a thickness of the order of 30 to 50 nm.
This sheathing ensures maximum effectiveness of the coating, its photocatalytic activity increasing as it is distributed over a greater specific surface. The preferred thickness takes into account the most commonly encountered mean size of the anatase TiO 2 crystallites.
Another subject-matter of the invention is the processes for the manufacture of the substrates defined above.
According to a first alternative form, the photocatalyic coating is deposited, in the liquid phase, on the production line itself for the fibrous material. The advantage to this alternative form lies in the fact that the still semi-finished fibrous material can be treated an the best use can be made of the temperature which it is at, for example, resulting in a saving in terms of time and of production cost. This, a first embodiment consists in “hot” depositing the coating between the fiberizing devices and the devices for receiving the fibres. The fiberizing devices can consist of glass centrifuging dishes, known as “internal centrifuging devices”, such as ones disclosed, for example, in Patents EP-0,189,534 and EP-0,519,797, making it possible to fiberize mineral wool of glass type, or devices for fiberizing by so-called external centrifuging using a succession of centrifuging wheels, such as ones disclosed, for example, in Patents EP-0,465,310 or EP-0,439,385, making it possible to obtain mineral wool of basalt rock type. It can also relate to devices for fiberizing by mechanical drawing, in order to obtain reinforcing glass strands, by air blowing or by steam blowing, according to processes well known to persons skilled in the art. Use is thus made of the fact that the fibres are still at a relatively high temperature by applying the coating, generally in solution/dispersion, in a solvent, for example an aqueous solvent, which evaporates on contact with or in the vicinity of the fibres. The heat can also make it possible to cure the component or components of the adhesion promoter, if they are of the resin type, or to decompose them thermally, if they are of the silicon-comprising precursor or metallic precursor type mentioned above.
As mentioned above, the coating in the liquid phase can be applied at the same time as an optional “binder” of the sizing composition type or even form part of it. It may also be preferable to apply it to the fibrous material before or after the said “binder”.
According to a second embodiment of this first alternative form, the photocatalytic coating, still generally in the liquid phase, can be deposited “after” the receiving devices which collect the fibres/filaments or strands resulting from the fiberizing devices and in particular before or during the post-fiberizing heat treatment of the fibrous material. Thus, for mineral wool of insulation type, the receiving devices are generally composed of a suction conveyor belt which gathers together the mineral wool and passes it into a forming oven. It can be judicious to apply the coating between the two devices (fiberizing/receiving), for example superficially, and to use the heat of the oven to cure or complete the coating, if necessary.
Likewise, in the field of reinforcing glass, the strands are drawn and wound off in the form of spools or cut up under the bushing, after having been appropriately sized, and then generally dried in heated chambers, before being converted and/or used.
As mentioned above, it is therefore possible to deposit the photocatalytic coating just under the bushing, in particular concomitantly with the deposition of the size, in which it can be incorporated. It is also possible to deposit it during the stage of finishing the spooled strands into finished products: it can, for example, relate to the conversion operation targeted at manufacturing mats of chopped strands, in a subsequent operation; it is also possible to deposit it on the downstream line, in particular during the conversion of the continuous strands, gathered together as a blanket, into a mat of continuous strands.
In the last two cases, the photocatalytic coating can be deposited by an ejection system of the adjusted sprayer type, before, during or at the same time as the binder used (or be used in combination with it in the same liquid phase).
According to a second alternative form, the photocatalytic coating is deposited in the liquid phase on the finished fibrous material, in a subsequent operation. What this involves is instead a “cold” treatment, requiring a post-deposition heat treatment in order to evaporate the solvent and optionally to cure or to complete, to constitute the coating.
Whatever the alternative form chosen, the coating can be deposited by different techniques. If the coating comprises “active” anatase crystallized TiO 2 powder or particles from the start, it is not necessary for the fibrous substrate to be very hot; temperatures of less than 300° C. and even of less than 200° C. may suffice, indeed even room temperature, and therefore temperatures which are found on production lines for the commonest mineral fibrous materials, temperatures which are in addition compatible with the sizes for these materials, which are generally organic, at least partly. If, on the other hand, it is necessary to generate anatase TiO 2 “in situ”, it is necessary to envisage temperatures of the order of 400° C., instead with fibrous materials devoid of binder in the general sense of the term and in a subsequent operation, for example by a process of sol-gel type.
In concrete terms, it is possible to choose to impregnate the fibrous material to the core and to use a technique of “dip-coating” type, where the fibrous material is at least partially immersed in a bath comprising the coating in the liquid phase. It is also possible to choose coating or spraying adapted to a surface treatment. The deposition can also be carried out in a fluid which is non-liquid in the usual sense of the term, for example in a hypercritical fluid.
Another subject-matter of the invention relates to the application of these treated substrates to thermal/sound insulation or facing materials, with a dirt-repellent, fungicidal, antibacterial or odour-controlling function, or to liquid or gas filters of paper type or of felt or mould type.
BRIEF DESCRIPTION OF THE DRAWINGS
Other advantageous details and characteristics of the invention become apparent from the non-limiting embodiments described below in reference to the following figures:
FIG. 1 shows a scanning electron microscopy (SEM) photograph of the surface of a fibrous material treated according to an embodiment of the invention;
FIG. 2 is another SEM photograph showing the surface of the fibrous material shown in FIG. 1 ; and
FIG. 3 is yet another SEM photograph showing the surface of the fibrous material shown in FIG. 1 .
DESCRIPTION OF THE PREFERRED EMBODIMENTS
All the following examples relate to the deposition of a coating for which the photocatalytic “active” components are made of anatase crystallized TiO 2 . As mentioned above, the invention applies in the same way to semi-conducting “active” components with photocatalytic properties similar to anatase TiO 2 and which can be provided in the same form, in particular zinc oxide, tin oxide and tungsten oxide.
EXAMPLE 1
a needled felt (dimensions 210×297×5 mm 3 ) composed of glass fibers of insulating type obtained by binder-free internal centrifuging and with a relative density of 55 kg/m 3 , was sprayed with an aqueous TiO 2 solution, sold under the trade name “ToSol” by Saga Céramics, over its entire thickness.
This solution containing particles of TiO 2 crystallized in anatase form, probably composed of crystallite agglomerates, these agglomerates having a mean size of the order of 20 to 80 nm. These particles are therefore the “active” components in terms of photocatalysis. The solution also contains an organometallic TiO 2 precursor which will decompose into predominantly amorphous TiO 2 by heat treatment and which will act as adhesion promoter.
The coating obtained was baked at 200° C. for 2 hours and contains anatase nanocrystals in an amorphous TiO 2 matrix. The yellow colour of the filter thus manufactured testifies to the presence of organic compounds originating from the precursor solution. After exposure to ultraviolet A radiation under a dose of 4 W/m2 for 2 hours, the yellow colour has completely disappeared, which shows complete decomposition of the residual organic pollutants.
EXAMPLE 2
Glass fibre of insulation type obtained by binder-free internal centrifuging was converted by the papermaking route in pure water. The paper obtained, circular with a diameter of 100 mm and a weight per unit area of 150 g/m2, was subsequently impregnated over its entire thickness by dip-coating it in an alcoholic dispersion containing, by volume, 5% water, 1% tetraethoxysilane (the adhesion promoter) and 1% anatase crystallized TiO 2 particles with a mean diameter of 30 nm (the “active” components). The paper was dried in the open air and then baked in an oven at 450 C for 30 minutes. This filter was subsequently placed over an inlet orifice of a fume cupboard. A control filter, without anatase TiO 2 , was placed over the neighbouring orifice. An ultraviolet A lamp shines on these filters at a dose of 4 W/m2. After the cupboard had been operated for 15 days, the treated filter was still white, whereas the untreated filter was fouled.
EXAMPLE 3
A composition for the sizing of glass wool of insulation type obtained by internal centrifuging was manufactured by mixing:
55 G of resin obtained by condensation of phenol and formaldehyde in an initial formaldehyde/phenol molar ratio of approximately 3.2/1, which condensation is carried out conventionally with a catalyst in the form of sodium hydroxide at 5.5% by weight with respect to the phenol,
45 g of urea, 3 g of aminopropyltrimethoxysilane, 0.3 g of ammonium sulphate, 6 g of 30% by volume aqueous ammonia, 1200 g of a 25% by weight dispersion in water of anatase crystallized TiO 2 particles, and 34 litres of water.
The TiO 2 particles have a mean diameter of approximately 45 nm. The adhesion promoter for the latter can be regarded as all the other components of the size and very particularly the silane.
This composition was sprayed via the sizing ring during a fiberizing of the glass wool under the centrifuging dishes. The felt obtained was subsequently passed on the line into an oven at 180° C. for 2 minutes. The felt has a weight per unit area of 560 g/m 2 and a loss on ignition of 1.4% (measurement known to a person skilled in the art, expressed by weight, by heating the felt at a temperature sufficient to remove all the organic compounds). A 1×20×40 mm 3 piece was removed and placed in a vessel with 20 g of an aqueous solution comprising 1 g/l of ethanol and 15 mg/l of hydrogen peroxide. The solution was shone on by a mercury lamp producing 4 W/m 2 of ultraviolet radiation and the concentration of hydrogen peroxide was monitored by colorimetry. Oxidation of ethanol by hydrogen peroxide, catalysed by the anatase TiO 2 irradiated with ultraviolet radiation, is observed.
The photocatalytic activity of the felt was evaluated by measuring the weight of hydrogen peroxide H 2 O 2 in milligrams which disappears per gram of fibre in the solution and per hour. The result was 4.4 mg H 2 O 2 /g.fibre/hour.
Samples of 200×300×200 mm3, coming from the same treatment, have been subjected to naturel sun exposure. Gradually the yellow colour, that is characteristic for the resin used, disappeared from the exposed surfaces and to some centimetres in depth. This vanishing clearly indicated a degradation of the phenolic resin used as well as the penetration of the photocatalytic effect inside the material. Similar results were obtained und controlled UVA radiation of 4 W/m 2 for 24 hours.
EXAMPLE 4
280 g of glycidoxypropyltrimethoxysilane were added to a sizing composition similar to that of Example 3 (other silane combining with the above to act as adhesion promoter). The felt obtained by fiberizing and sizing with this solution was stoved at 180° C. for 2 minutes. The felt has a weight per unit area of 1 kg/m 2 and a loss on ignition of 1.4%. The measurement of the photocatalytic activity, carried out as in Example 3, gave a value of 3 mg H 2 O 2 /g.fibre/hour.
FIGS. 1 , 2 and 3 show, in three different scales, a fibre covered with the photocatalytic coating. FIG. 1 shows more particularly a fibre, at the surface of which is clearly distinguished a sheathing of TiO 2 particles, two successive magnifications being shown in FIGS. 2 and 3 .
In conclusion, it is found that the coating of the invention exhibits a proven photocatalytic activity on fibres, whatever the implementational alternative forms:
Example 1 illustrates a deposition “in a subsequent operation”, outside the line for the production of mineral wool, using “precrystallized” TiO 2 particles and an inorganic adhesion promoter manufactured in situ, on a fibrous substrate of felt type.
Example 2 also illustrates a deposition “in a subsequent operation”, on a fibrous substrate of paper type, with precrystallized TiO 2 particles and a silicon-comprising adhesion promoter.
Examples 3 and 4 illustrate an in-line hot deposition under the fiberizing devices, which will make possible treatment within the thickness of the fibrous material, with “precrystallized” TiO 2 particles and adhesion promoters of the family of the silanes in combination with the components of a standard size, in the aqueous phase.
Photocatalytic webs based on mineral fibres were manufactured using a plant which makes it possible to carry out the impregnation of a glass web in a sizing solution, the application os suction to this web (in order to remove the excess binder) and, finally, its baking in an oven, the entire process being carried out in-line and continuously. The web is unwound on a conveyor belt, conveyed into the sizing bath via an impregnation roller, passes above a negative-pressure tank (suction device) and is finally conveyed by a second conveyor belt into the baking oven.
Various types of photocatalytic media were synthesized according to this process, in accordance with the following examples:
EXAMPLE 5
A Medium for the Purification of Gases
An 80 g/m2 glass web was impregnated with an aqueous solution containing 3.1% of Glymo (glycidoxypropyltrimethoxysilane) and 2.9% of titanium dioxide nanoparticles at a rate of 0.2 m/min.
This web, having been subjected to a suction equivalent to a water column of 35 mm, was subsequently baked at 200° C. for 10 minutes. The resulting loss on ignition is 7%.
Measurements of effectiveness in the gas phase were then carried out under the following conditions: 150×200 mm 2 of the resulting product were placed in a cylindrical photocatalysis reactor. This reactor is composed of an axial UV-A lamp (365 nm), around which is surrounded, with a spacing of 1 cm, the photocatalytic medium in 3 layers, and of an aluminium jacket. The intensity of the irradiation on the web is 1 mW/cm 2 . The reactor is inserted in a closed circuit, with recirculation, the gas passing through the medium from the inside of the closed cylinder over the web towards the outside.
The volume of the cell (photocatalysis reactor) is 0.9 l and that of the complete circuit (immobilized volume) is one litre. The experiments consisted in evaluating the photocatalytic decomposition of n-hexane.
To do this, various amounts of n-hexane (ranging up to 2000 ppm in air) were injected into the circuit, the flow rate of the latter being regulated at 1 l/min. At regular intervals, 50 μl samples of gas were withdrawn in order to measure the concerntration of n-hexane present in the circuit.
It was shown that the direct decomposition by UV of n-hexane is negligible, just as its absorption by the medium. In constrat, n-hexane is virtually 100% decomposed in less than one hour when it passes through the photocatalytic medium, though under weak UV irradiation.
EXAMPLE 6
A Medium for Liquid Purification
According to the same process, a 60 g/m glass web was impregnated in an aqueous solution comprising 1 g/l of A1100 silane and 5 g/l of titanium dioxide (sold under the name P25 by Degussa) held in suspension by appropriate means.
The web was impregnated in-line at 0.6 m/min, the excess binder having been removed under a negative pressure of 90 mm of water column. The poduct was baked at 300° C. for 30 minutes. Measurements of effectiveness in the liquid phase were then carried out in order to describe this material.
A circular specimen of web (diameter 100 mm) was placed at mid-height in a 300 ml beaker. The bottom and the edges of the receptacle having been rendered opaque, the beaker is illuminated by a bank of UV-A lamps (365 mm) delivering a power of 3.5 mW/cm2 to the web. An aqueous solution (deionized water) containing 10 mg/l of phenol is poured into the device and is kept stirred magnetically. The decrease in concentration of the phenol is then monitored, samples being withdrawn at regular time intervals, by a UV spectrometer sold by Dr Lange.
It could be confirmed that virtually 100% of the phenol had disappeared over approximately at most one hour.
More generally, these last two examples show the advantage of the use of a web formed of photocatalytic mineral fibres, such as those manufactured, in purification operations in a liquid medium as in the gas phase.
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A substrate includes a fibrous material in the form of mineral wool of insulation type and/or glass fibers of reinforcement type, and a coating provided over at least a portion of a surface of the fibrous material, the coating having photocatalytic properties and including at least partially crystallized semiconductor material which has photocatalytic properties and which is of the oxide or sulphide type, and a bonding agent configured to adhere fibers of the fibrous material to each other, the bonding agent including an adhesion promoting agent configured to promote the adhesion of the coating to the fibrous material. The bonding agent is selected from one of an adhesive agent for mineral wool, a sizing agent for reinforcing threads, a bonding agent for a mat or web obtained from reinforcement threads, and an adhesive agent for a web obtained from glass wool.
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FIELD OF THE INVENTION
The present invention relates to the assembly of precision components, such as lens elements and their barrel mountings, and more particularly to methods and apparatus for interfitting such high precision components accurately, in an automated fashion.
BACKGROUND OF INVENTION
Manufacturing competitiveness is increasingly dependent on the use of automatons in the construction of products; and modern assembly lines employ apparatus, often referred to as industrial robots, which are automated (for example, operate with a relatively high degree of self control) to perform various assembly steps of an overall product construction. Moreover, the current designs for such automated assembly apparatus aim towards "flexible" automation, which refers to the capability of a particular automated apparatus to be used, perhaps with some modifications, for the assembly of more than one type of product.
U.S. Pat. No. 2,094,043 provides an example of a prior art apparatus for assembling precision components of an acoustic device. This apparatus uses two jig structures that precisely position and hold respective components and a gauge element that accurately aligns the jig structures, one to the other, before the jig structures are moved to interfit and attach their supported components. These jig structures and the gauge element are themselves highly precise in dimension and expensive to fabricate. Also, they are relatively unique to the particular acoustic device disclosed. Further, the overall assembly procedure requires operator intervention to align the gauge element with one of the jig structures so that the assembly procedure is not subject to a high degree of automation. Thus, improvements are desired over the '043 patent approach to enable automated assembly of precision components, with a good degree of product "flexibility".
The assembly of optical lens elements with their cylindrical housings, commonly called "barrels", provides another good example of a procedure requiring the accurate interfitting of precision components. The traditional approach for such an assembly is to mount the lens element and lens barrel into complimentary precision fixtures. The fixtures are then moved to a precise interfit relation that correctly mounts the lens element in the barrel. As in the previous example, the lens and barrel fixtures must be accurately dimensioned and are expensive to fabricate. Again, the fixtures are relatively unique to the particular lens and barrel configurations and do not have a good degree of product "flexibility".
SUMMARY OF INVENTION
Thus, one important purpose of the present invention is to provide improved apparatus and methods for the assembly of precision components. For example, the invention can provide improvements in regard to the degrees of precision and automation afforded. Another significant advantage of the present invention is its relative simplicity, and therefore inexpensiveness. A further advantage of the present invention is the degree to which it is "flexible" as to usefulness in assembling different precision products automatically.
In one aspect the present invention constitutes apparatus for automatically assembling components such as a part and a mount that have a precision outlines. Such apparatus includes a housing that reciprocates toward and away from a work platform and has a similarly reciprocating piston that is movable within a chamber of the housing to cause a gripping end of the piston to protrude from, and withdraw within, the housing chamber's mouth. The chamber mouth has alignment surfaces that contact and precisely position a part that is gripped and withdrawn by the piston. Alignment surfaces of the mouth also precisely contact and position the mount as the housing is moved onto the mount. The chamber behind the piston can be coupled to a positive pressure source to force a gripped part into interfit with an aligned mount.
In another aspect the present invention constitutes a method for automatically assembling a part and a mount having precise peripheral features. Such method includes the steps of: (i) moving the gripper end of a piston to engage a part; (ii) withdrawing the piston into a housing chamber so that the engaged part contacts an inwardly tapered alignment surface and slides into an aligned position on the gripper end; (iii) moving the housing toward the mount so that an alignment surface cams the mount into precise alignment with the gripped part and (iv) moving the piston toward the aligned mount to complete interfit of the part and mount.
BRIEF DESCRIPTION OF DRAWINGS
The subsequent descriptions of preferred embodiments of the invention are made with reference to the accompanying drawings wherein:
FIG. 1 is a schematic perspective view of an automated assembly system incorporating one embodiment of the present invention;
FIG. 2 is a cross-sectional view showing the details of one embodiment of the present invention, at a beginning stage of its assembly operation;
FIG. 3 is a fragmentary view, similar to FIG. 2, but showing a subsequent stage of the inventions operation;
FIG. 4 is a view like FIG. 3, but showing yet another subsequent stage of invention operation;
FIG. 5 is a view like FIG. 4, but showing still another subsequent stage of the invention operation;
FIGS. 6 and 7 are fragmentary cross-section views illustrating non-aligned conditions of a part and mount respectively, which can occur during the FIG. 2-5 sequences; and
FIG. 8 is an enlarged cross-section showing the details of another preferred chamber and alignment mouth construction for practice of the present invention.
DETAILED DESCRIPTION OF INVENTION
Referring to FIG. 1, there is illustrated an automated assembly station 1 that employs one preferred embodiment of the present invention. Thus, automatic assembly system 10 is operative to interfit parts, e.g., lenses 2, into mounts, e.g., lens barrels 3. As shown schematically, the lens 2 and barrel 3 are moved in succession to a work platform 4, e.g., by a transport belt 6 and drive and control subsystem 7. Subsytem 7 can include suitable photosensor circuits and logic (not shown) to stop belt 6 when lenses 2 and barrels 3 sequentially arrive at a work position, generally aligned beneath assembly device 11 and above work platform 4. Assembly system 10 also includes a negative/positive air pressure supply subsystem 8 and a vertical drive and control subsystem 9, whose functions are coordinated with the transport drive and control subsystem 7 by an overall system control, e.g., a microcomputer, not shown. Those skilled in the art will understand that the assembly system 10 can form a part of a more comprehensive system wherein further assembly operations, utilizing the assembled packages of parts and mounts 2,3, are effected.
Referring now to FIG. 2, the assembly device 11 is shown in cross-section to comprise housing 12 which is machined or otherwise constructed to include a piston chamber 13 having an outlet opening mouth 14 comprising inwardly tapering alignment guide surfaces 15. A piston member 20 is mounted within chamber 13 and has a cylindrical side 21 wall configuration sized to slide in relatively air tight relation with the cylindrical guide surface 16. If desired, sealing rings can be mounted in the guide surface 16, which are aligned to direct the reciprocating movement of the piston toward and away from the work platform 4.
The top of piston member 20 has a recess 22 which supports and positions one end 31 of coil spring 30, (whose other end 32 presses against the top interior wall of chamber 13). The spring 30 has a resilient extension sufficient to urge the piston control edge 25 to bottom upon chamber control ledge 18. The device 11, in its initial position is moved by vertical drive and control 9 to a location relative to the transport belt 6 such that, when surfaces 18, 25 abut, gripper end 26 of piston member 20 is resting on, or proximate, the top of a lens element 2 on belt 6. This constitutes a position such as schematically shown in FIG. 2.
The gripper end 26 is constructed to have a domed central recess 27 and a peripheral rim surface 28. A central air passage 29 couples recess 28 to the recess 22 and thus to the interior of chamber 13, and to the air pressure control system 8 (via port 19 in the housing 12).
The cooperative functioning of the components of assembly device 11 will be more fully understood by the description of exemplary assembly operation sequences, which follows, referring also to FIGS. 3-7. Thus, in the stage of operation shown in FIG. 2, housing 12 has been moved by drive and control 9 to its nominal start position, and spring 30 has moved piston member 20 downward so that surfaces 18 and 25 abut and rim 28 presses lightly on, or is closely proximate, the top of lens 2.
Next, under overall system control, negative/positive air pressure supply 8 is signaled to provide a vacuum in chamber 13. The reduced chamber pressure is communicated, via passage 29, to recess 27, and lens 2 moves to seal the recess. After passage 29 is blocked by lens 2, the piston 20 moves upwardly, against the force of spring 30, so that gripper end 26 withdraws into opening 14 and the gripped lens 2 is precisely centered by alignment surfaces 15. For example, as is illustrated in FIG. 6, an edge of an off-center lens 2 will contact inwardly tapering surface 15 and be slid to the centered position shown in FIG. 3, as the piston moves to its top position. A stop 34 can be provided on the inner wall of chamber 13 to limit the upward movement of piston 20 at a position such as shown in FIG. 3. The vacuum level is selected in coordination with the spring constant of spring 30 so that lens 2 is held to rim 28 (in a laterally slidable condition) when piston member 20 is withdrawn in its top position.
Next under overall system control, the transport drive and control subsystem 7 positions a lens barrel 3 at platform 4, generally centered with respect to the alignment surfaces 15 of housing mouth 14. The vertical drive and control subsystem 9 moves the housing 12 downwardly over the generally positioned lens barrel 3 so that surfaces 15 contact and cam barrel 3 to a precisely centered position, as shown in FIG. 4. FIG. 7 shows an exemplary intermediate stage where a surface 15 contacts the peripheral edge of barrel 3 and begins to cam the barrel to slide on belt 6 to a precise assembly position (e.g. centered) visa vis lens 2. The centered condition can be sensed, e.g., by an increase in resistance to the downward movement of housing 12, and the vertical drive is terminated. With the assembly device 11 now in the stage of operation shown in FIG. 4, the negative/positive air supply 8 is actuated to terminate the vacuum supplied to chamber 13 and thus allow spring 30 to move the precisely positioned lens 2 (still gripped by sufficient vacuum to maintain its centered condition) into engagement with precisely positioned barrel (still held in centered condition by alignment surfaces 15). To provide additional pressure to force lens 2 into interfit with barrel 3, supply subsystem 8 is actuated to provide a positive pressure (e.g., 4 psi) into the chamber via port 19, thus further urging piston 20 and lens 2 downwardly. With the assembly completed as shown in FIG. 5, the vertical drive is activated to move housing 12 upwardly and transport belt 6 is operated by drive and control 7 to move the assembled unit 2, 3 downstream, and to position the lens 2 of the next component pair for assembly.
It will be appreciated that other work station arrangements can be utilized. In one preferred alternative, a carton of nested lenses is positioned at a work station adjacent a carton of nested barrels. A robotic system, not shown, x-y positions the assembly device 11, visa vis the cartons, and other controls operate as described above to perform the assembly.
It will be appreciated that various other part and part-mounts can be assembled utilizing the present invention. For example, with appropriate modification of alignment surfaces 15, elements with congruent outlines, or corresponding outlines other than circular, can be guided to precise relative positions for assembly. With other modifications, parts and mounts with different precise outline features can be positioned in accurate relative positions by correspondingly different alignment surfaces, for subsequent engagement.
FIG. 8 illustrates another portion preferred chamber and guide surface configuration for mounting circular elements such as lenses and lens barrels. In this embodiment surfaces 15a are uniquely designed to center a lens barrel and surfaces 15b are designed to center a lens. Also, ledge 41 provides a stop to rest on the top of the barrel mount, ledge 42 provides a stop for upward movement of the piston member and ledge 43 provides a stop for downward movement of the piston.
The invention has been described with particular reference to preferred embodiment thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention.
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Apparatus and method for automatically interfitting a part and mount utilize a housing having a chamber and an inwardly tapered alignment surface. A piston reciprocates in the chamber and has a gripper end that moves out of and into the housing, past the alignment surface, when alternating spring and air pressure forces act on the piston. Such movement of the piston accurately positions a gripped part, and the housing then reciprocates so that the alignment surfaces accurately position a mount. The piston then moves the part to an interfit with the mount.
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RELATED APPLICATIONS
[0001] This application contains subject matter related to the subject matter of commonly-owned U.S. application Ser. No. 13/944,787, “Gear Noise Reduction In Opposed-Piston Engines” and commonly-owned U.S. application Ser. No. 14/074,618, “Gear Noise Reduction In Opposed-Piston Engines”, which is a continuation-in-part of U.S. application Ser. No. 13/944,787.
BACKGROUND
[0002] The field is reduction of noise, vibration, and harshness (NVH) in an opposed-piston engine. More specifically, the field covers controlling backlash in the gear train of an opposed-piston engine with a split gear construction.
[0003] Gear vibration and clash in an internal combustion engine of a vehicle lead to intense whining and/or sharp impulse noise which can cause operator and passenger discomfort. Engine whine and rattle also add to the constant cacophony that makes proximity to transportation routes and industrial sites very unpleasant. Consequently, performance standards and environmental regulations relating to engines increasingly include NVH limits.
[0004] When gears interface with each other, there are usually gaps between the interfacing gear teeth. As the gears rotate, these gaps are closed when the teeth move to make contact, which can result in gear rattle. In some instances, the space is called backlash; in other instances the movement made to close the gaps is called backlash. In either case, it is desirable to control, reduce, or eliminate backlash.
[0005] The gear train of an opposed-piston engine with dual crankshafts inherently experiences torque reversals. In the case where a phase difference is provided between the crankshafts in order to differentiate port opening and closing times, the gear train is subjected to multiple torque reversals during every cycle of engine operation. With backlash, the engine's operation is afflicted with audible clatter and hammering as instantaneous accelerations caused by the reversals cascade through the gear train. Even without an inter-crankshaft phase difference, momentary inter-gear torque reversals result from idler bounce and/or gear/shaft rotational distortion.
[0006] The well-known split gear construction provides an underpinning for various solutions to gear train backlash. In a split gear construction, two or more gears are arranged in an abutting, face-to-face relationship on a common shaft or post so as to act as a single gear. Various means are employed to impose and maintain a rotational offset between the gears by a distance amounting to some fraction of a gear tooth. The relative movement effectively increases the width of the split gear's teeth, thereby closing interstitial space between meshed gear teeth. Some of these split gear constructions use bias members such as springs that continuously act between the gears so as to maintain a rotational offset that varies in response to rotation of the gear and to sporadic accelerations caused by torque reversals, etc. The rotational offset automatically moves the gears to maintain closure of the gaps between meshed gear teeth. See, for example, U.S. Pat. No. 2,607,238 and U.S. Pat. No. 3,174,356. Because the resulting back-and-forth movements of the split gear teeth resemble the opening and closing actions of scissor blades, these gears may also be called “scissor gears”. In this regard, see US publication 20110030489.
[0007] In related U.S. application Ser. Nos. 13/944,787 and 14/074,618 split gear constructions include combinations of compliant and stiff gears. The compliant gears receive the torque load first and slightly deform as the stiff gears begin to absorb the gear loads. As a compliant gear deforms, a stiff gear increasingly absorbs torque loads, which are transmitted via friction between compliant and stiff gears. Consequently, only a compliant gear transfers the total torque load to a hub thereby reducing or eliminating gear backlash.
[0008] The spring-biased split gear constructions are intended to automatically eliminate backlash by relative rotation between the two gears in opposing directions. Thus, as a succession of torque reversals occurs, slack is taken up by a succession of rotational adjustments of the split gears. This results in a continuous back-and-forth movement of the gears that causes wear of the gear parts and consumes energy. The split gear constructions of the related applications depend on the availability of compliant materials which may be in short supply, or, if available, unsuited to particular applications. Therefore, it is desirable to have spring-biased gear constructions with anti-backlash capability available that reduce wear, conserve energy, and operate well in a broad range of applications.
[0009] According to this disclosure the technological problem of backlash in the gear train of an opposed-piston engine is solved with a split gear construction that achieves wear reduction, energy conservation, and good operation in a broad range of applications. In this construction, relative rotation between two gears of a split gear assembly is allowed in a first direction, but constrained in the second direction. A first gear of the split gear is automatically rotated with respect to the second gear in the first direction until it contacts one flank of a tooth groove in a mating gear. At this point the second gear is in contact with the opposite flank of the tooth groove and backlash is reduced, if not eliminated, as the split gear rotates. When torque reversal occurs, the counter-rotation constraint keeps the two gears locked in their previously-rotated positions and no backlash is available.
SUMMARY
[0010] A split gear assembly includes first and second gears, a spring mechanism that acts to rotate the first gear relative to the second gear in a first direction, and a one-way clutch mechanism that prevents rotation of the first gear relative to the second gear in a second direction opposite the first direction.
[0011] A gear train assembly coupling two crankshafts of an opposed-piston engine that are disposed in a parallel, spaced-apart relationship includes a driving gear coupled to a first crankshaft and a split gear assembly engaged with the driving gear to transfer rotation from the driving gear to the split gear assembly. The split gear assembly includes first and second gears, a spring mechanism that acts to rotate the first gear relative to the second gear in a first direction, and a one-way clutch mechanism that prevents rotation of the first gear relative to the second gear in a second direction opposite the first direction.
[0012] Backlash is controlled in an opposed-piston engine that includes two crankshafts disposed in a parallel, spaced-apart relationship and a gear train coupling the first and second crankshafts. The gear train includes a driving gear coupled to the first crankshaft and a split gear assembly engaged with the driving gear to transfer rotation from the driving gear to the split gear assembly. A method of controlling the backlash includes driving rotation of the first and second crankshafts, angularly offsetting a first gear of the split gear assembly relative to a second gear in a first direction, and preventing relative angular movement of the first gear relative to the second gear in a second direction opposite the first direction.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a side view of a gear train in an opposed-piston engine equipped with two crankshafts.
[0014] FIG. 2 is an end view of the same gear train with a gear box cover removed.
[0015] FIG. 3 is front view of a split gear assembly for an opposed-piston gear train according to this disclosure.
[0016] FIG. 4 is an isometric view of a portion of the split gear assembly of this disclosure.
[0017] FIG. 5 is a partial elevation view showing a split gear according to this disclosure in meshed engagement with a mating gear.
[0018] FIG. 6 is an exploded view of the split gear assembly of this disclosure.
DETAILED DESCRIPTION
[0019] Constructions and methods of operation directed to the control of backlash in opposed-piston engines are described in detail with reference to the drawings. FIGS. 1 and 2 show a gear train 10 for an opposed-piston engine equipped with two crankshafts 12 and 14 . The crankshafts 12 and 14 are disposed in parallel, in a spaced-apart arrangement. The precise opposed-piston configuration by which the crankshafts 12 and 14 are driven for rotation is a matter of design choice; one example is seen in FIG. 1C of commonly-owned U.S. Ser. No. 13/858,943 and PCT/US2014/033066. The gear train 10 includes a plurality of gear assemblies, two of which (indicated by reference numeral 16 ) are fixed to respective ends of the crankshafts 12 and 14 for rotation thereby, and one of which (indicated by reference numeral 15 ) is fixed to the end of a power take-off shaft 18 . In this configuration, two idler gear assemblies 19 are provided; each idler gear assembly is mounted for rotation on a fixed shaft or post. As a result of the configuration of the gear train 10 , the crankshafts 12 and 14 are co-rotating, that is to say, they rotate in the same direction. However, this is not meant to so limit the scope of this disclosure. In fact, the gear assembly construction disclosed in this specification can be incorporated into gear trains with fewer, or more, gear assemblies, and with counter-rotating crankshafts. Thus, although these figures show five gears for the gear train it should be understood that the number and types of gears required is dictated only by the particular engine configuration. Also, the output drive shaft can be connected to any one of the gears. In any case, these gear train assemblies often experience backlash that causes vibration, noise and gear tooth wear during torque reversal events or other normal gear operation that occur during each cycle of engine operation.
[0020] FIG. 3 is a front view of a split gear assembly 30 for a gear train coupling two crankshafts of an opposed-piston engine according to this disclosure. At least one of the gear assemblies in the gear train 10 of FIGS. 1 and 2 may include the split gear assembly 30 ; in some instances, some or all of the gear assemblies 15 , 16 , and 19 may include the split gear assembly 30 . Preferably, at least one of the idler gear assemblies 19 includes the split gear assembly. Referring to FIGS. 3 and 6 , the split gear assembly 30 includes a first gear 31 (the “anti-backlash gear”), a second gear 40 (the “power gear”), a spring mechanism 50 , and a one-way clutch mechanism 60 .
[0021] As per FIGS. 3 , 4 and 6 , the anti-backlash gear 31 has an annular structure 32 with a plurality of gear teeth 33 extending radially outwardly therefrom. The annular structure 32 transitions to an axially-extending annular flange 34 . Wedge-shaped indentations 35 are formed in an inner annular wall of the flange 34 . Each indentation 35 has a ramped wall portion 37 extending tangentially to the center of the anti-backlash gear between opposing end wall portions 38 and 39 . The ramped wall portions 37 are angled in the same direction with respect to the center of the split gear assembly. The power gear 40 has an annular structure 41 with a plurality of gear teeth 42 extending radially outwardly therefrom. The annular structure 41 transitions to a circular floor 43 that extends radially inwardly of the power gear 40 to an axially-extending annular flange 45 . The flange 45 has a smooth outer annular wall 46 . The peripheries on the gears 31 and 40 where the gear teeth are located have identical diameters; preferably, but not necessarily, the teeth 33 and 42 are identically shaped in the radial direction of the split gear 30 . When the gears 31 and 40 are aligned for assembly as per FIGS. 3 and 4 , with the teeth 33 and 42 registered, they present and operate as a single gear.
[0022] As per FIGS. 4 and 6 , the spring mechanism 50 includes a plurality of springs 51 . In the exemplary embodiment of the figures, there are three coiled springs 51 , although this is not meant to limit either the number or type of springs in the spring assembly. The one-way clutch mechanism 60 includes a plurality of coiled springs 61 and cylindrical rollers 62 . Each of the springs 61 is associated with a respective one of the rollers 62 to form a clutch unit. In the exemplary embodiment of the figures, there are six clutch units, although this is not meant to limit the number of clutch units. Further, although the one-way clutch mechanism is illustrated as being constituted of roller/spring units, this is not meant to be limiting; other clutch units may include, for example, sprag devices.
[0023] The power gear 40 may be formed from a hardened steel material or other material suitable for handling the load stresses demands of a gear train. The anti-backlash gear 31 may be of a softer material that has been either hardened or coated to ensure uniform wear. The springs 51 and 61 may be helical devices, formed from hardened steel. The rollers 62 may be solid cylindrical devices formed from hardened steel.
[0024] As per FIGS. 3 , 4 , and 6 , the anti-backlash gear 31 and the power gear 40 , with their teeth registered, are assembled into a close abutting relationship in which the flange 34 is received in space defined by the annular structure 41 , the floor 43 , and the flange 45 . With the gears 31 and 40 thus positioned, a circular array of wedge-shaped spaces is defined between the wedge-shaped indentations 35 of the anti-backlash gear 31 and the outer flange wall 46 of the power gear 40 .
[0025] As per FIGS. 4 and 5 , the springs 51 of the spring mechanism are distributed in a circumferential array in the split gear assembly 30 , each being received in a respective one of the shaped spaces 35 . Each spring 51 is compressed, having a first end fixed relative to the anti-backlash gear by a wall portion 38 of the anti-backlash gear 31 a second end fixed relative to the power gear 40 by a pin 64 fixed to the floor 43 of the power gear 40 . The compressed conditions of the springs 51 act between the backlash and power gears 31 and 40 by exerting a bias that causes relative rotation between the gears 31 and 40 . In the example shown the direction of relative movement of the anti-backlash gear with respect to the power gear is clockwise (CW); but this is not meant to be limiting since rearrangement of parts can make the bias direction counter-clockwise (CCW).
[0026] The clutch units 61 , 62 of the one-way clutch mechanism are distributed in a circumferential array in the split gear assembly 30 , where they are interspersed with the springs 51 of the spring mechanism. Each clutch unit is received in a respective one of the shaped spaces 35 . Each spring 61 is compressed between a wall portion 39 of the anti-backlash gear 31 and a roller 62 . The compressed condition of the spring 61 acts between the wall portion 39 of the anti-backlash gear 31 and the roller 62 by forcing the roller 62 into increasingly smaller wedge-shaped space between the angled wall portion 37 of the anti-backlash gear 31 and the smooth outer wall 46 of the power gear flange 45 . In the example shown this locks the anti-backlash gear 31 against rotation relative to the power gear 40 in a direction opposite to the direction of relative movement resulting from the bias action of the spring mechanism 50 . In the example shown in the figures, the one-way clutch mechanism 60 locks the anti-backlash gear 31 against counter-clockwise (CCW) movement relative to the power gear 40 ; but this is not meant to be limiting since rearrangement of parts can make the locked direction clockwise (CW).
[0027] Referring now to FIGS. 3 , 4 , and 5 , the split gear 30 operates as a single gear with means to control backlash in the meshing interface with a mating gear 70 . In the meshing interface, the teeth 42 of the power gear 40 are in normal contact with the teeth 72 of the mating gear 70 . The anti-backlash gear 31 is spring loaded by the three weak springs 51 , which angularly offsets the anti-backlash gear 31 relative to the power gear 40 in a first direction (CW in the example) so that it moves slightly ahead of the power gear 40 . As best seen in FIG. 5 , this ensures that the leading flank of the anti-backlash gear 31 is always in contact with the trailing flank of the mating gear 70 whenever the trailing flank of the power gear 41 is in contact with the leading flank of the mating gear 70 . That is to say, the leading and trailing edges of the split gear 30 are always in contact with the leading and trailing flanks of the mating gear 70 whenever in driving force contact, (two to three gear teeth at any one time).
[0028] Still referring to FIG. 5 , a clutch unit 61 , 62 is shown located within a wedge-shaped space 35 of the anti-backlash gear 31 . The spring 61 keeps the roller 62 lodged in the wedge-shaped space 31 . If, during a torque reversal, pressures are exerted on the anti-backlash gear 31 in a CCW direction the roller 62 is forced toward the wall portion 38 , thereby locking the anti-backlash gear 31 from CCW movement. The combination of continuous trailing and leading flank contacts of the meshing gear teeth produced by the spring mechanism 50 with the directional locking of the clutch mechanism 60 guarantees anti-backlash control during torque reversals.
[0029] It is preferred that the springs 51 of the spring mechanism 50 be no stronger than required to ensure that the anti-backlash gear 31 is always in an advanced state in relation to the power gear 40 . However, it is also possible that normal engine vibrations, caused by other than gear backlash conditions, could cause the same effect, which might eliminate the need for the springs 51 . In contrast, the springs 61 of the one-way clutch mechanism 60 should have strength sufficient to withstand the high forces encountered during high-power operation. Under these conditions, it will be the case that the strength of the clutch springs 61 exceeds the strength of the biasing springs 51 .
[0030] It is preferred that in a five-gear engine configuration at least the two idler gears 19 have the split gear configuration with anti-backlash capability as described above. Regardless of the number of gears in the gearbox, one or more idler gears preferably would be split gears with anti-backlash capability as described above. The split gear 30 may be mounted for rotation in a gear train using conventional arrangements. For example, with reference to FIGS. 1 , 3 , and 6 , when used as an idler gear 19 , a split gear assembly 30 according to this specification may be assembled as described, received on a hub 80 , and rotatably mounted on a stationary post 85 in a gear box 86 .
[0031] It will be understood that the scope of the invention as described and illustrated herein is not limited to the described embodiments. Those of skill will appreciate that various modifications, additions, known equivalents, and substitutions can be made to the split gear assembly without departing from the scope and spirit of the invention as set forth in the following claims.
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Backlash is controlled in an opposed-piston engine that includes two crankshafts disposed in a parallel, spaced-apart relationship and a gear train coupling the first and second crankshafts, the gear train including a driving gear coupled to the first crankshaft and a split gear assembly engaged with the driving gear to transfer rotation from the driving gear to the split gear assembly. The split gear assembly includes first and second gears, a spring mechanism that acts to angularly offset the first gear relative to the second gear in a first direction, and a one-way clutch mechanism that prevents relative angular movement of the first gear relative to the second gear in a second direction opposite the first direction.
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RELATED PATENT APPLICATION
[0001] This application claims priority to commonly owned U.S. Provisional Patent Application Ser. No. 61/578,502; filed Dec. 21, 2011; entitled “Current/Voltage Interface,” by Joseph Julicher; which is hereby incorporated by reference herein for all purposes.
TECHNICAL FIELD
[0002] The present disclosure relates to a sensor interface, and, in particular, for a microcontroller having a current input interface using an internal sampling capacitor, timer and analog-to-digital converter.
BACKGROUND
[0003] Some sensors such as the photo transistors produce a current which needs to be converted into a digital value. Conventional photo smoke sensors require external circuitry to handle the often very small output currents therefrom. For example, present technology photo smoke detectors use high speed amplifiers to detect the light change in the smoke chamber. A current technology interface for a current to voltage conversion use transconductance amplifiers which require an operational amplifier. Operational amplifiers may also be used to control the excitation current for a light emitting diode (LED) in a smoke detection photo chamber.
[0004] There are three types of smoke detectors available today: (1) photoelectric, (2) ionization, and (3) a combination of photoelectric and ionization that have both types of sensors. A photoelectric alarm is triggered when smoke detected based upon the amount of light detected from a light source onto a light sensor. In an ion smoke detector, ionized air molecules attach to the smoke particles that enter the chamber, reducing the ionizing current and triggering the smoke alarm detection circuits.
[0005] The ion detector reacts faster than the photoelectric detector in responding to flaming fires, and the photoelectric detector is more responsive to smoldering fires. Because an ion detector tests the air for small combustible particles, it can be fooled by chemical or paint particles in the atmosphere. The photoelectric detector, which needs to “see” the smoke from the fire, can be fooled by dust, steam or even spider webs. Though both offer protection against undetected fires, ion detectors experience a higher incidence of nuisance alarms.
[0006] Optical beam smoke detectors work on the principle of light obscuration, where the presence of smoke blocks some of the light from the light source beam. Once a certain percentage of the transmitted light has been blocked by the smoke, a fire alarm is generated. Optical beam smoke detectors are typically used to detect fires in large commercial and industrial buildings, as components in a larger fire alarm system.
[0007] Optical beam smoke detectors consist of at least one light transmitter and one receiver, which is photosensitive. The photosensitive receiver monitors light produced by the transmitter under normal conditions. In the absence of smoke, light passes from the light transmitter to the receiver in a straight line. In a fire, when smoke falls within the path of the beam detector, some of the light is absorbed or scattered by the smoke particles. This creates a decrease in the received light signal, leading to an increase in optical obscuration i.e. a reduction of transmittance of light across the beam path.
[0008] It would be desirable to improve the reliability, lower the power consumption and reduce manufacturing costs of fire alarms using photo optical smoke detectors.
SUMMARY
[0009] Therefore there is a need for an improved current interface to an external sensor having a current out, and in particular integrated within a microcontroller.
[0010] According to an embodiment, a system for measuring a current may comprise: a current source; and a microcontroller having at least one external port pin directly connected with the current source, the microcontroller comprising: an analog-to digital converter (ADC); a sample and hold capacitor associated with the ADC; a timer; a first switch coupling between the sample and hold capacitor and the external port pin, and controlled by the timer; and a second switch coupled to the sample and hold capacitor, wherein the second switch may be adapted for discharging the sample and hold capacitor.
[0011] According to a further embodiment, the microcontroller may comprises a control unit for controlling said ADC, timer, and said second switch. According to a further embodiment, the control unit may be a state machine. According to a further embodiment, the control unit may be configured to control the second switch to discharge the sample capacitor and after the capacitor has been discharged, to control the second switch to be opened and the first switch to be closed, and after a predetermined time period to control the first switch to be opened and an analog-to-digital conversion started by the ADC. According to a further embodiment, the current source may be an optical photo detector excited by a light source.
[0012] According to a further embodiment, the optical photo detector detects smoke from a fire when a light level detected from the light source changes due to the smoke. According to a further embodiment, the current source may be selected from the group consisting of a resistance temperature detector (RTD), a humidity detector, a pressure transducer, and a flow rate transducer. According to a further embodiment, the light source and optical photo detector may be periodically turned on by the microcontroller for conserving power thereto.
[0013] According to another embodiment, a system for measuring a current may comprise: a current source; and a microcontroller having at least one external port pin directly connected with the current source, the microcontroller may comprise: an analog-to digital converter (ADC); a sample and hold capacitor associated with the ADC; a timer having an output for providing a voltage pulse to the current source for a defined period of time; a first switch coupled to the sample and hold capacitor, wherein the first switch may be adapted for discharging the sample and hold capacitor; and a second switch for coupling the sample and hold capacitor to the ADC for conversion of a voltage on the sample and hold capacitor to a digital representation thereof.
[0014] According to yet another embodiment, an integrated circuit device for determining a process variable based upon a process sensor having a current output may comprise: a capacitor having a known capacitance value; a timer generating a time period of known value; an analog-to-digital converter (ADC); and a digital processor having a memory, the digital processor may be coupled to the timer and the ADC, wherein the known value capacitor coupled to the current output of the process sensor and begins charging with the current from the process sensor upon a start signal from the timer, the known value capacitor may be decoupled from the current output of the process sensor upon a stop signal from the timer, the ADC samples and converts a voltage on the capacitor to a digital representation thereof, and the digital processor reads from the ADC the digital representation of the voltage and determines therefrom a process value.
[0015] According to a further embodiment, the digital processor may determine whether the value of the process variable comprises an alarm condition. According to a further embodiment, the process sensor may be an optical photo detector. According to a further embodiment, the optical photo detector detects smoke from a fire. According to a further embodiment, an analog multiplexer may have a first input coupled to the optical photo detector and a second input coupled to an ionization chamber smoke detector, wherein the optical photo detector and ionization chamber smoke detector may be located within a smoke detector chamber having an opening to allow smoke to enter therein.
[0016] According to a further embodiment, a light emitting diode (LED) may be used as a light source for the optical photo detector. According to a further embodiment, the LED may be controlled by the digital processor. According to a further embodiment, a look-up table may be used for converting the digital representations into process values, wherein the look-up table may be stored in the memory. According to a further embodiment, the integrated circuit device may be a microcontroller.
[0017] According to till another embodiment, a method for measuring a current from a process sensor may comprise the steps of: shorting a capacitor to substantially zero volts; coupling the capacitor to a process sensor having a current output; charging the capacitor with the current output from the process sensor; decoupling the capacitor from the process sensor after a certain time period; converting a voltage on the capacitor to a digital representation thereof with an analog-to-digital converter (ADC); reading the digital representation from the ADC with a digital processor; and determining a process value from the digital representation with the digital processor.
[0018] According to a further embodiment of the method, the process sensor may be an optical photo detector. According to a further embodiment of the method, the optical photo detector detects smoke from a fire. According to a further embodiment of the method, the step of determining a smoke alarm condition may be determined from the process value.
[0019] According to another embodiment, a method for measuring a current from a process sensor may comprise the steps of: shorting a capacitor having a known capacitance to substantially zero volts; applying a voltage pulse having a known time period to a process sensor having a current output that may be coupled to the capacitor; charging the capacitor with the current output from the process sensor; converting a voltage on the capacitor to a digital representation thereof with an analog-to-digital converter (ADC); reading the digital representation from the ADC with a digital processor; and determining a process value from the digital representation with the digital processor.
[0020] According to a further embodiment of the method, the process sensor may be an optical photo detector. According to a further embodiment of the method, the optical photo detector detects smoke from a fire. According to a further embodiment of the method, the step of determining a smoke alarm condition may be determined from the process value.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] A more complete understanding of the present disclosure may be acquired by referring to the following description taken in conjunction with the accompanying drawings wherein:
[0022] FIG. 1 illustrates a schematic block diagram of a sensor coupled to a current input interface of a microcontroller, according to a specific example embodiment of this disclosure;
[0023] FIG. 2 illustrates a time-voltage graph of a capacitor being charged from a constant current source;
[0024] FIG. 3 illustrates a schematic block diagram of a photo-optic sensor and light source coupled to current input and output interfaces of a microcontroller, according to another specific example embodiment of this disclosure;
[0025] FIG. 4 illustrates schematic timing diagrams for operation of the peripheral functions shown in FIG. 3 , according to the teachings of this disclosure;
[0026] FIG. 5 illustrates a schematic process flow diagram of the operation of the circuit shown in FIG. 3 , according to the teachings of this disclosure;
[0027] FIG. 6 illustrates a schematic block diagram of a smoke detector system using a combination of photoelectric and ionization sensors, according to yet another specific example embodiment of this disclosure; and
[0028] FIG. 7 illustrates a schematic block diagram of a photo-optic sensor and light source coupled to current input and output interfaces of a microcontroller, according to yet another specific example embodiment of this disclosure.
[0029] While the present disclosure is susceptible to various modifications and alternative forms, specific example embodiments thereof have been shown in the drawings and are herein described in detail. It should be understood, however, that the description herein of specific example embodiments is not intended to limit the disclosure to the particular forms disclosed herein, but on the contrary, this disclosure is to cover all modifications and equivalents as defined by the appended claims.
DETAILED DESCRIPTION
[0030] According to embodiments of this disclosure discussed herein will allow, in particular, small currents to be directly measured with a microcontroller without any external components. For example, a timed pulse may be used in place of an operational amplifier controlled linear current source. A pulse timer peripheral is already present on many microcontroller units that can provide a 65,000:1 dynamic range which will easily provide the calibration range required. The current can be captured as a charge current on an internal analog-to-digital converter (ADC) sample and hold (S/H) capacitor. The ADC can then be used to produce a digital value proportional to the current supplied to the S/H capacitor over a known precision time period.
[0031] The ADC sampling capacitor comprises certain constraints. However, these constraints are known. External solutions require additional amplification steps to combat parasitic affects of the equipment printed circuit board (PCB) and other environment conditions. By moving the necessary circuit parts inside of the microcontroller and ADC, these parasitic affects are readily known, controlled, and the circuit solution is more compact and sensitive to sensor inputs.
[0032] Such a current/voltage interface can be advantageously be used in a smoke detector and will significantly reduce the cost of interfacing to an optical photo smoke sensor. According to various embodiments, a current sourced by an external device such as a photo chamber is connected to the input of an ADC. The internal sampling capacitor of the ADC accepts the current charge and creates a voltage linearly over a fixed precision time period. After the fixed precision time period has elapsed, the voltage on the S/H capacitor may be measured by starting a conversion from analog to digital with the ADC.
[0033] Portions of a Charge Time Measurement Unit (CTMU) may be used in determining the voltage charge value on the S/H capacitor. The CTMU is more fully described in Microchip applications notes AN1250, AN1375, etc., available at www.microchip.com, and U.S. Pat. Nos. 7,460,441 B2 and 7,764,213 B2; wherein all are hereby incorporated by reference herein for all purposes. The CTMU voltage charge measurement accuracy is achieved by charging a known value capacitor from a current source over a known time period, then sampling a voltage developed on the charged capacitor. This sampled voltage is then converted into a digital value with an analog-to-digital converter (ADC) and, optionally, a look-up table may be used, or other means, to convert the digital value of the sampled voltage into a value for comparison against a reference value. If the sampled voltage value is significantly different, as in an alarm condition, e.g., smoke detection, than the reference value then an alarm may be initiated. If the sampled voltage value is within desired values then no alarm condition exists.
[0034] The various embodiments described herein, provide for the ability to create a cost effective solution for applications using sensors having current outputs. Thus, the need for expensive operational amplifiers and associated circuitry is removed. An interface according to various embodiments may be advantageously used in smoke detector photo chambers to detect fast occurring smoky fires. A photo chamber consists of an LED and a Photodiode. As discussed above, the photodiodes are often measured using high speed transconductance amplifiers (15 MHz GBW), followed by low pass active filters and finally ADC or comparators according to conventional systems. Using the internal ADC capacitor eliminates external components and saves power.
[0035] Referring now to the drawings, the details of specific example embodiments are schematically illustrated. Like elements in the drawings will be represented by like numbers, and similar elements will be represented by like numbers with a different lower case letter suffix.
[0036] Referring to FIG. 1 , depicted is a schematic block diagram of a sensor 112 coupled to a current input interface of a microcontroller 102 , according to a specific example embodiment of this disclosure. The microcontroller 102 may comprise a charge time measurement unit (CTMU) 104 , an analog-to-digital converter (ADC) 106 , a digital processor and memory 108 , and a precision timer 110 . All circuit functions, e.g., internal peripherals, reside in the microcontroller 102 necessary for reading (measuring) the current output of the sensor 112 . The sensor 112 having a current output may be for example, but is not limited to, a photo-electric diode, a resistance temperature detector (RTD), humidity detector, pressure transducer, flow rate transducer, etc., wherein the sensor 112 supplies a current proportional to the sensed process variable, e.g., smoke, temperature, etc. A constant current source sensor will enable precise conversion of the process variable, and a current source that is non-linear may still be used to provide process measurement values that may be converted to useful information with a look-up table and/or curve fitting formulas, etc. For monitoring an alarm condition the linearity of the current source sensor is of secondary importance.
[0037] Referring to FIG. 2 , depicted is a time-voltage graph of a capacitor being charged from a constant current source. When a capacitor 220 is charged through a constant current source 112 (e.g., sensor), the voltage, V, across the capacitor 220 increases linearly with time, according to equation (1):
[0000] I=C*dV/dT Eq. (1)
[0000] where C is the capacitance value of the capacitor 220 , I is the current from the constant current source 112 and V is the voltage on the capacitor 220 at time T. When any two values of the current, I; time, T; and voltage, V are known, the other unknown value may be calculated from the two known values. For example, if the capacitance of the capacitor 220 and the time T=T 2 −T 1 are known, and the voltage V on the capacitor 220 is measured, a current charge may be determined. This allows conversion of the voltage charge (e.g., voltage on the capacitor 220 ) to the measured process variable. A simple voltage to process variable value look-up table may also be provided and stored in the memory of the digital processor 108 .
[0038] Referring to FIG. 3 , depicted is a schematic block diagram of a photo-optic sensor and light source coupled to current input and output interfaces of a microcontroller, according to another specific example embodiment of this disclosure. The microcontroller 102 comprises an internal analog-to-digital converter (ADC) 106 having an associated sample and hold (S/H) capacitor 220 . Furthermore a sample and hold switch 330 and a discharge switch 332 are provided. The discharge switch 332 discharges the S/H capacitor 220 to substantially zero (0) volts. An ADC switch 334 is provided to couple the ADC 106 to the S/H capacitor 220 during an analog-to-digital conversion cycle.
[0039] A precision timer 110 may be used to precisely control the sample and hold switch 330 . A digital processor 108 may be used to control the discharge switch 332 and the ADC switch 334 (or the ADC 106 peripheral may control the switch 334 ) and start the precision timer 110 , or an independent control unit (not shown) may be separately provided from digital processor 108 to independently control the operation of the entire CTMU peripheral in the microcontroller 102 . According to other embodiments, this control unit (not shown) may be, for example, a programmable state machine or any other suitable sequential control unit within the microcontroller 102 . The current source is indicated with numeral 112 a and may be a sensor, for example a photo smoke detector, and a light source light emitting diode (LED) 338 , both in smoke chamber (see FIG. 6 ). An output driver 336 may be used to turn on the light source LED 338 and supply operating voltage to the sensor 112 a periodically for conservation of power, e.g., battery power.
[0040] Referring to FIG. 4 , depicted are schematic timing diagrams for operation of the peripheral functions shown in FIG. 3 , according to the teachings of this disclosure. Switch 332 closes, shorting out any charge on the S/H capacitor 220 to zero volts. Then the precision timer 110 closes the sample and hold switch 330 for a know fixed period of time, T=T 2 −T 1 . Then after time T the sample and hold switch 330 opens. This causes the sample and hold capacitor 220 to be charged at a rate determined by the current source, e.g., the current from the sensor 112 . After the time period T has elapsed, the ADC switch 334 closes and the ADC 106 converts the voltage charge on the S/H capacitor 220 to a digital representation thereof. The digital processor 108 may thereafter read this digital representation for further processing, e.g., alarm notification and/or process variable representation.
[0041] Referring to FIG. 5 , depicted is a schematic process flow diagram of the operation of the circuit shown in FIG. 3 , according to the teachings of this disclosure. In step 540 the S/H capacitor 220 is shorted to ground to remove any charge thereon to zero (0) volts. In step 542 the S/H capacitor 220 is coupled to a current source, e.g., current output sensor 112 a for a precision time determined by, for example but not limited to, the precision timer 110 . After the precision time period has elapsed, in step 544 the resultant voltage charge on the S/H capacitor 220 is converted to a digital representation by the ADC 106 . In step 546 the digital representation is read by the digital processor 108 . In step 548 a determination is made whether the read digital representation of the voltage charge on the S/H capacitor 220 indicates that an alarm condition exists, e.g., smoke detected. If an alarm condition has been determined in step 548 , an alarm is generated in step 550 .
[0042] Referring to FIG. 6 , depicted is a schematic block diagram of a smoke detector system using a combination of photoelectric and ionization sensors, according to yet another specific example embodiment of this disclosure. The microcontroller 102 a comprises a charge time measurement unit (CTMU) 104 , an internal analog-to-digital converter (ADC) 106 , a digital processor and memory 108 , a precision timer 110 , a multiplexer 660 , and an output driver 636 . Functionally the microcontroller 102 a operates in substantially the same way as the microcontroller 102 shown in FIG. 3 with the addition of the multiplexer 660 that is coupled to a photo-electric smoke sensor 612 , excited by a light source light emitting diode (LED) 638 , and an ionization chamber smoke detector 640 located in a smoke detection chamber 642 . The smoke detection chamber 642 has an opening 644 to allow smoke to enter therein. The microcontroller 102 a shown in FIG. 6 enables a dual function smoke detector having both optical and ionization smoke detectors, and requiring only a single inexpensive integrated circuit microcontroller 102 a for operation thereof. The constant current source of the CTMU 104 is replaced by the photo-electric smoke sensor 612
[0043] Referring to FIG. 7 , depicted is a schematic block diagram of a photo-optic sensor and light source coupled to current input and output interfaces of a microcontroller, according to yet another specific example embodiment of this disclosure. The microcontroller 102 b comprises an internal analog-to-digital converter (ADC) 106 having an associated sample and hold (S/H) capacitor 220 . Furthermore a discharge switch 332 and an ADC switch 334 are provided. The discharge switch 332 discharges the S/H capacitor 220 to substantially zero (0) volts. The ADC switch 334 couples the ADC 106 to the S/H capacitor 220 during an analog-to-digital conversion cycle.
[0044] A precision timer 110 may be used to precisely control a voltage pulse to a light source 338 and a current source 112 a. A digital processor 108 may be used to control the discharge switch 332 and the ADC switch 334 (or the ADC 106 peripheral may control the switch 334 ) and also start the precision timer 110 , or an independent control unit (not shown) may be separately provided from digital processor 108 to independently control the operation of the entire CTMU type peripheral in the microcontroller 102 b. According to other embodiments, this control unit (not shown) may be, for example, a programmable state machine or any other suitable sequential control unit within the microcontroller 102 . The current source 112 a may be a sensor, for example a photo smoke detector, and a light source light emitting diode (LED) 338 , both in smoke chamber (see FIG. 6 ). An output driver 336 may be used to drive the light source LED 338 and current source 112 a with a pulse having a pulse width of a time duration determined by the timer 110 . Periodically generating the pulse will conserve power, e.g., battery power. The diode 730 prevents a voltage discharge path from the capacitor 220 through the LED 338 .
[0045] While embodiments of this disclosure have been depicted, described, and are defined by reference to example embodiments of the disclosure, such references do not imply a limitation on the disclosure, and no such limitation is to be inferred. The subject matter disclosed is capable of considerable modification, alteration, and equivalents in form and function, as will occur to those ordinarily skilled in the pertinent art and having the benefit of this disclosure. The depicted and described embodiments of this disclosure are examples only, and are not exhaustive of the scope of the disclosure.
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External conditions, e.g., smoke, temperature, humidity, humidity, pressure, flow rate, etc., affects a sensor's characteristics, wherein the sensor provides a current output representative of its characteristics as affected by the external conditions. The current output of the sensor is coupled to a sample and hold capacitor for a precision time period thereby charging the sample and hold capacitor to a voltage proportional to current provided by the sensor over the precision time period. The voltage on the sample and hold capacitor is converted to a digital representation and a determination is made whether the external condition represents an alarm situation, e.g., smoke detected from a fire.
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This application claims priority from U.S. application No. 60/805,972, filed Jun. 27, 2006, which application is hereby incorporated herein by reference for all purposes.
BACKGROUND
A corporation keeping track of assets (e.g., desks, chairs, computers) will often try to accomplish this by means of assets tags. Each asset tag is adhesively secured to an asset, and bears a tracking number or bar code or both. Carrying out an inventory is a tedious process, requiring a lot of people and a lot of time. It is unworkable to carry out a building-wide inventory more often than about once a year.
Given the problems with numbered or bar-coded tags, many investigators have tried to keep track of assets using radio tags such as RFID tags. But locating radio tags in a large or multi-room space is not easy. Among the reasons why this is not easy are the following.
Range. Most radio tags work only if the reader is immediately adjacent to the tag. For example, many RFID tags can only be read at a distance of inches. Among the RFID tags that can be read from more than a few inches away, many can only be read from more than a few inches away in the special case where a high-gain antenna is pointed directly at the tag.
Collisions and area reads. Most radio tags simply respond when powered. If many such tags are nearby to each other, all within a reading area of a reader, what generally happens is that all the tags respond simultaneously, and the collision often means that few or none of the tags can actually be read. Complicated collision-avoidance and disambiguation schemes can be attempted but such schemes often do not work well.
Detuning. Many radio tags many recent RFID tags, get detuned if they are nearby to large pieces of metal or other conductors. With many prior-art systems, a detuned tag may be treated as a tag that does not exist, as it will fail to respond to queries.
Skin depth. Many radio tags, especially many recent RFID tags, simply cannot be reached if there are intervening objects blocking the RF signals. The RF signals are unable to pass back and forth through the intervening objects.
Some approaches that have attempted to overcome these problems are prodigiously expensive.
It would thus be extremely desirable to have a reasonably priced system that would permit area reads, over a substantial range (many feet), robust against detuning, and effective even in the face of intervening objects.
SUMMARY OF THE INVENTION
A cart has at least three wheels. It has one or more loop antennas, and a radio transceiver connected with the antennas. The antennas and transceiver operate at a frequency lower than 1 megahertz. The loop antennas are each at least 0.2 square meters in area. The cart is moved to an area such as a room, and the transceiver communicates with various RF tags in the room. Because of the antenna configuration, the portion of spectrum employed, and the power levels used, the cart is able to communicate with most if not all of the RF tags in the room. The cart can then be moved to another area such as another room, and the process repeated. In this way an inventory of tags can be made without expensive permanently installed infrastructure. The system is robust against interferers such as large metal objects and intervening objects.
DESCRIPTION OF THE DRAWING
FIG. 1 shows how signal strength drops off with distance.
FIG. 2 shows the information of FIG. 1 but on a logarithmic scale.
FIG. 3 shows how signal strength drops off as a tag that is ten feet away moves off axis.
FIG. 4 shows how signal strength drops off as a tag that is five feet away moves off axis.
FIG. 5 shows how signal strength drops off as a tag that is five feet away rotates about a Z axis.
FIG. 6 shows how signal strength drops off as a tag that is five feet away rotates about a Z axis while positioned 45 degrees left of a vector normal to the antenna.
FIG. 7 shows how signal strength changes as a tag that is five feet away rotates about an axis normal to the antenna.
FIG. 8 shows an exemplary cart assembly.
FIG. 9 shows three cube antennas, each connected with a respective router.
DETAILED DESCRIPTION
The radio tags employed can, for example, be tags such as those described in U.S. Pat. No. 7,049,963 entitled “Networked RF tag for tracking freight” and assigned to the same assignee as the present invention, which patent is incorporated herein by reference.
The transceiver on the cart can, for example, be a transceiver such as that described in copending US application number [tunable loop], filed ?? and assigned to the same assignee as the present invention, which application is incorporated herein by reference. The transceiver can transmit at, say, a predetermined multiple of 32768 Hertz (the standard watch crystal frequency) such as 65 kHz or 133 kHz. It uses an antenna that a copper coil forming a rectangle 21 inches by 13 inches. The cart may carry three such antennas, each orthogonal to the other two antennas. The transceiver can switch from one antenna to the next, and even if one antenna is not well coupled with a particular tag in a room, very likely one of the other two antennas will turn out to be well coupled with that particular tag.
As described in more detail in the copending application, the transceiver has an antenna tuner which is used in real time to achieve an optimal impedence coupling between the transceiver and the antenna. In addition, in an exemplary embodiment, the transceiver is able to be tuned upwards or downwards from a nominal frequency. By use of the up-tuning and down-tuning, and by use of the antenna tuner, and by use of the several loop antennas, it turns out to be possible to communicate even with “difficult” tags which old prior-art transceivers might not be able to reach. For example if a tag is “detuned” by proximity to a large body of metal, the transceiver described here will likely be able to communicate with the tag where old prior-art transceivers almost certainly would not be able to do so.
Some examples based upon actual signal strength measurements illustrate that the system according to the invention works better than prior-art systems. It will also be appreciated that this knowledge of the manner in which signal strength drops off can permit a cart and transceiver and several antennas to localize a tag in 3-dimensional space about the cart.
FIG. 1 shows how signal strength drops off with distance. In this experiment, measurements were made of signal versus distance on the center line of the antenna with the tag axis pointed at the center of the antenna. This experimental result is important for two reasons. First, it shows that it is possible to read a tag even though it is 16 feet away, and in this respect the result is very different from what is obtained with many earlier RFID technologies. Second, it may be appreciated that the received signal strength may be used as an indicator of the distance to the tag. FIG. 2 shows the information of FIG. 1 but on a logarithmic scale. In this experiment and in the ones described below, the antenna was 21 inches by 13 inches, wound on a frame made of polymethyl methacrylate. It turns out that signal strength versus distance for this combination of tag and base station can be very well described by the equation S=85000/(R 2.5 ) where R is in feet, with saturation effects occurring between 0 and 5 feet. This may be extended with additional antennas.
FIG. 3 shows the results of an experiment in which signal strength measurements were made at the base station (transceiver and antenna which could be on a cart) with the tag on a 10-foot radius arc in front and to the left (CCW) of the antenna. The tag was oriented so that it was at the same height as the antenna and the tag's axis was pointed at the center of the antenna for all readings. This, too, is important for two distinct reasons. First, it shows that it is possible to read a tag even though the tag is far off (as much as 70 degrees) from the antenna axis. In this respect the result is very different from what would be seen with many RFID technologies, where a tag that is ten feet away will simply be unreadable at all even if it is only ten or twenty degrees off the antenna axis. Second, it may be appreciated that the received signal strength may be used as an indicator of the extent to which the tag is off the antenna axis. Similarly, FIG. 4 shows how signal strength drops off as a tag that is five feet away moves off axis.
FIG. 5 shows how signal strength drops off as a tag that is five feet away rotates about a Z axis. In this experiment, measurements of signal vs rotation of the tag about the Z axis were made with the tag positioned 5 feet from the antenna on the center line and the tag antenna normal axis pointed at the center of the antenna. In this case the tag is on the antenna axis, and the tag rotates about a Z axis, defined as an axis that is perpendicular to the vector normal to the tag. Stated differently, if one draws a line from the antenna to the tag, the Z axis is perpendicular to that line. This is important because it shows that it is possible to read a tag even though the tag is not “facing” the antenna. In contrast, with many RFID technologies, a tag may be read only if it is facing the antenna (or facing directly away from the antenna). Stated differently, the experimental result was that rotation of the tag about its Z axis when the normal vector to its antenna is in the horizontal plane causes a decrease in signal strength read proportional to the cosine of the angle between the tag antenna normal and the field direction.
Similarly, FIG. 6 shows how signal strength drops off as a tag that is five feet away rotates about a Z axis while positioned 45 degrees left of a vector normal to the antenna. With the tag located at 5 feet from the antenna and off the antenna axis by 45 degrees CCW, the tag was rotated about its Z axis by a full 360 degrees. The zero-degree point was with the tag antenna's axis pointed directly at the antenna's center. It shows that for many angles the tag can be read, despite being off the antenna normal vector and despite its not facing the antenna. It appears that field lines when the tag is off the antenna's center line are not radial, and in fact with the tag at the 45-degree point 5 feet from the tag, the field is offset 25 degrees from radial.
FIG. 7 shows how signal strength changes as a tag that is five feet away rotates about an axis normal to the antenna. With the tag located at 5 feet from the antenna on the antenna's center line, the tag was rotated about the normal vector to the tag's antenna. This shows that so long as the tag faces the antenna, it does not matter if the tag is rotated within the plane of the tag face. Stated differently, rotation of the tag about the normal vector to its antenna doesn't change the signal strength read.
If three antennas are employed, and if the antennas are not all coplanar or parallel to each other, these results indicate that to some extent the received signal strength on the three antennas will permit localizing the tag in three-dimensional space. Preferably the antennas would each be orthogonal to the other two, but orthogonality is not required. (Even if the antennas are not orthogonal, mathematical computations or lookup tables would permit approximating 3-D locations based upon signal strengths.)
FIG. 8 shows an exemplary cart 81 assembly. It includes a cart 88 , and wheels 82 a , 82 b , and 82 c . Superposed on the cart 88 is the cube antenna 83 . The cube antenna 83 includes square antennas 84 , 85 , 86 , and 87 . Antennas 86 and 87 are parallel with the floor. It is not, of course, required that the antennas be square, and indeed they could be circular in shape or other random shapes. Square antennas are, in some ways, easier to fabricate and to assemble into three axes as portrayed here.
FIG. 9 shows three cube antennas 96 , 93 , and 92 , each connected with a respective router 95 , 94 , and 91 . A camera 97 is nearby. The three cube antennas, each with three orthogonal antennas, can detect and localize a tag in five dimensions—3D position as well as tag pitch and yaw. The experimental results suggest a three-dimensional resolution of plus or minus two to six inches, and an angle resolution to within 10 to 20 degrees depending upon the angle.
What follows is one example of a method according to the invention. A building has at least first second, and third rooms. A cart is provided, the cart having at least three wheels, the cart having a first first loop antenna and a radio transceiver, the first loop antenna communicatively coupled with the radio transceiver, the radio transceiver operating at a frequency lower than 1 megahertz, the first first loop antenna having an area greater than 0.2 square meters. The cart is placed in the first room. While the cart is in the first room, the cart communicates by means of the first loop antenna with at least first, second, and third tags, each of the first, second, and third tags being at least five feet from the cart, the communication with the first, second, and third tags achieved without reorienting the first loop antenna, the communication with the first, second, and third tags each yielding an identification of each of the first, second, and third tags. The cart is moved to the second room. While the cart is in the second room, the cart communicates by means of the first loop antenna with at least fourth, fifth, and sixth tags, each of the fourth, fifth, and sixth tags being at least five feet from the cart, the communication with the fourth, fifth, and sixth tags achieved without reorienting the first loop antenna, the communication with the fourth, fifth, and sixth tags each yielding an identification of each of the fourth, fifth, and sixth tags. The cart is moved to the third room. While the cart is in the third room, the cart communicates by means of the first loop antenna with at least seventh, eighth, and ninth tags, each of the seventh, eighth, and ninth tags being at least five feet from the cart, the communication with the seventh, eighth, and ninth tags achieved without reorienting the first loop antenna, the communication with the seventh, eighth, and ninth tags each yielding an identification of each of the seventh, eighth, and ninth tags. The first, fourth, and seventh tags are each fixed respectively to the first, second, and third rooms, whereby the cart is able to know unequivocally which room it is in. The second, third, fifth, sixth, eighth, and ninth tags are each attached to respective movable objects. Optionally, the cart further comprises a second loop antenna not coplanar with the first loop antenna, the second loop antenna communicatively coupled with the radio transceiver, the method further comprising the steps of selectively operatively coupling the first loop antenna and not the second loop antenna to the transceiver; and selectively operatively coupling the second loop antenna and not the first loop antenna to the transceiver.
One application of the system and method according to the invention is corporate inventory control in a building. Instead of, or in addition to, applying traditional numbered or bar-coded inventory labels to assets, RF tags are applied to assets. A cart according to the invention is pushed through the rooms of the building, one by one. The first time through the building is a time-consuming trip as the system must detect and disambiguate all or nearly all of the tags in the building, and associate each tag with a location such as a particular room. Subsequent trips through the building, however, may be faster, since the system can look for a particular tag in a room where it was previously detected, addressing that tag individually and thus saving the step of detecting it by seeking out a tag that had not previously been detected in that room.
It will be appreciated that many tags working at higher frequencies (e.g. the tens of gigahertz used with some RFID tags) are able to be read very quickly, one after the other. In contrast, the system described here is only able to proceed at a bandwidth of a few hundred bits per second. This is not, however, a big problem because the cart can be moved from one room to the next as slowly or as quickly as is needed. In an exemplary embodiment, the cart will have a display showing progress in a particular room, and will let a human operator know when the cart is finished in a room and can be moved to a different room.
In an exemplary embodiment, each room has a fixed tag that permits the cart to know which room it is in. The cart may then enumerate the rooms during an initial trip through the building. On later trips through the building, the cart can “check off” the rooms one by one and can alert the human operator if some particular room is overlooked.
It will be appreciated that in many buildings, there is a cleaning crew which passes through the building periodically, such as daily or every few days. The cleaning cart pushed by the crew can carry the transceiver and antennas described here, and thus represents little or no additional labor cost beyond the fixed labor cost of the cleaning crew.
In a hotel, the cart can be a housekeeping cart pushed by a housekeeper. The cart can, among other things, monitor that nothing has been stolen (e.g. a television or hair dryer or ironing board) as well as monitoring the housekeeping status of each room (not yet cleaned, cleaned for a returning guest, and cleaned for a new check-in).
In a grocery store, a customer grocery cart may may carry the transceiver and antenna described here. If so, the cart can detect fixed-position tags permitting the cart to learn where it is in the store.
In all these cases an exemplary cart will also have an 802.11 b/g wireless node in communication with 802.11 b/g access points located at various positions within the building. By means of a WiFi link the cart (or carts, if there is more than one) can communicate with a central host.
In a building where high-value items are stored, this system will permit real-time or near-real-time visibility of the items. One example is a hospital in which high-value items such as stents or artificial joints are stored. Each stent or joint is tagged with a tag of the type described here, and when a cart according to the invention passes through the room, the stents and joints may be counted and located. Any changes from the previous inventory can be annunciated.
Those skilled in the art will have no difficulty devising myriad obvious variants and improvements upon the invention, all of which are intended to be encompassed by the claims which follow.
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A cart has at least three wheels. It has one or more loop antennas, and a radio transceiver connected with the antennas. The antennas and transceiver operate at a frequency lower than 1 megahertz. The loop antennas are each at least 0.2 square meters in area. The cart is moved to an area such as a room, and the transceiver communicates with various RF tags in the room. Because of the antenna configuration, the portion of spectrum employed, and the power levels used, the cart is able to communicate with most if not all of the RF tags in the room. The cart can then be moved to another area such as another room, and the process repeated. In this way an inventory of tags can be made without expensive permanently installed infrastructure. The system is robust against interferers such as large metal objects and intervening objects.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates generally to pavers, such as, for example, asphalt pavers used in continuous paving operations for long strips of pavement, such as on highways, airport runways, parking lots and the like. More particularly, the invention relates to grade reference systems which are instrumental in controlling the grade of the paved surfaces.
2. Description of Related Art
All pavements designed particularly for vehicles moving at high speeds typically include controlled transverse slopes to assure proper water run-off. Grade controls to assure compliance to surveyed grades along the lengths of pavement strips are equally important for pavements used for high speed operations, such as interstate highways and airport runways. Straight runs are particularly important with respect to airport runways. Highways require smooth transitions from straight runs into ascending or descending grades. A particular problem in the prior art relates to effectively mounting grade reference sensors on pavers using screed extensions to enable the pavers of laying down pavement of various widths. Accordingly, state of the art pavers have the capabilities to effectively more than double their standard paving widths by the use of screed extensions.
Typically, the use of screed extensions brings about a need to position grade reference systems outward with respect to the centerline of the paver using the screed extensions. For example, typical grade sensors make reference to and indicate deviations from one of various types of surveyed grade references, such as direct sensing of an existing grade by a sensing shoe, by referencing to a string line on a travelling ski, or to string lines which are strung off to the sides of the path of the paver to indicate the surveyed grade of the pavement. Thus, the grade reference sensor necessarily has to be adjusted outward from the centerline of the paver, as the paving width of the paver is increased by additions to the screed.
According to a current practice, the grade sensors are usually supported by the front part of the pull arms by which the screed of the paver is pulled along, such front part being near the pull point through which the pulling force of a tractor is transmitted to the screed. A grade sensor positioned near the screed receives only attenuated deviation indications of upcoming grade changes. With substantially no anticipatory grade change indications, transitions from one indicated grade to another tend to be more abrupt, as some floating screeds may be slow to react to grade changes, the actual grade change may lag the desired grade. Abrupt changes are likely to be undesirable for paving highways or runways designed for handling high speed traffic. For an anticipation of a grade change and a smoother transition from one grade to another, the grade sensors are preferably mounted somewhere intermediate the front and rear ends of the pull arms.
The forward ends of the pull arms present no particular difficulty for mounting support arms of standard length for grade sensors. Such standard support arms would be applicable when the paver is used without screed extensions and the grade reference line is located about three feet laterally away from the pull arm. When the paver is used with screed extensions, however, supporting the grade sensors becomes more difficult. The difficulty results from the lack of a support base for attaching the cantilevered length of the support needed to position the grade sensors laterally outside of the width to be paved. The forward ends of the rear pull arms are typically located laterally on both sides of the tractor unit. Up to now, long extensions for supporting the grade sensors have had to be strengthened by, for example, overhead braces which were attached at their base ends to the superstructure of the tractor unit. Frequently more than one length of extension and its respective brace may be needed to provide the proper support for grade control sensors suspended at different widths. The grade sensor supports may, consequently, present a substantial inventory of accessory hardware, all of which may need to be held in readiness at job sites. Maintaining the readiness of the additional extensions and braces adds to the cost of paving operations.
Also, it has been recognized that a grade reference sensing position just ahead of the screed offers a more positive control over transverse changes between opposite sides of the screed than a grade reference sensing position near the pull point of the screed pull arm on the tractor. A sensing position referenced substantially to the screed will give a continuous indication of the position of the screed to the grade reference, hence the string line. If the quality of a paving job is to be judged by the accuracy to which the paver lays the pavement to the grade reference, an anticipatory grade change away from the current string line reference is undesirable.
On the other hand, a sensor location on the pull arms near the screed has been found to be sensitive to lateral flexing of the pull arms during the paving operation. Such flexing about longitudinal axes of the pull arms is particularly noticeable when the screed is adjusted for a "crown", such that the center of the screed is raised with respect to its ends.
It is therefore desirable to overcome problems that relate to shifting of a grade sensor because of a flexure of a pull arm, to accommodate extensible screeds and resulting transverse shifts in the location of grade reference lines, and to provide adaptability to changes in requirements and to achieve a balance between response to anticipatory grade changes and maintaining an optimum degree of control over screed elevation with respect to a string line or similar grade reference.
SUMMARY OF THE INVENTION
According to the present invention a grade reference system of a paving machine includes a pivotally mounted support arm member carried by a screed pull arm intermediate the rear and forward ends of the screed pull arm. The support arm member pivots about a pivot axis through an arc in a horizontal plane from an extended position transverse to the direction of travel of the paving machine to a forward pivoted position in such direction of travel. The outer end of the support arm member includes mounting provisions for a grade sensor. An arc of pivotal adjustment of the support arm member permits the grade sensor to become located at a selected position ahead of the front end of a screed assembly in the rear of the paving machine. The pivot axis of the support arm member is adjustable transversely to the paving machine for lateral outward or inward adjustments of the grade sensor with respect to the centerline of the paving machine.
One particular aspect of the invention includes two of the support arm members each of which is pivotally attached at its pivot axis to one of a pair of support arms. Each of the support arms is slidably mounted in a guide extending substantially across the width of the paving machine, which guides prevent rotational movement of the support arms about their respective longitudinal axes. Locking provisions selectively inhibit movement of the support arms along their longitudinal axes to prevent inadvertent change from an adjusted position of the support arms.
The outer arm members of the support arms are mounted for pivotal movement in a horizontal plane between their extended positions transversely to the longitudinal centerline of the paving machine to forward pivoted positions to locate the respective grade sensors forward of the support arm guide and increase a sensitivity to anticipatory grade changes.
An advantage of the grade reference system in accordance with the invention is the ability to stow those lengths of the support arms which are in excess of a proper needed length, and to immediately have the maximum lengths of the support arms available at the paving machine when a maximum paving width is desirable. In a fully retracted position of the support arms, the outer support arm members may be pivoted forward into a folded retracted position adjacent the respective pull arms to facilitate movement of the paving machine between job sites.
Another advantage of the invention is found in a wide support base for the cantilevered extension of the support arms which tends to stabilize the outer support arm members and impart rigidity to the grade reference system. Since the outer support arm members are furthermore pivotally movable over a range of pivoted positions between a straight extension and a forward position when the support arms are fully extended, an optimum forward position may be combined with an optimum extended position.
BRIEF DESCRIPTION OF THE DRAWINGS
Various advantages and features of the invention will be best understood when the following detailed description of a preferred embodiment thereof is read in reference to the appended drawings wherein:
FIG. 1 is a schematic top view of a paving machine including a screed assembly and screed extensions thereof, and a grade reference system and illustrating among other features extensible support arms including contemplated positions within a preferred range of movement of outer support arm members, as contemplated by the present invention:
FIG. 2 is a pictorial view of a support arm assembly shown apart from a mounted position on a paving machine and on a larger scale to show further details of the support arm assembly;
FIG. 3 is a section through the support assembly of the grade reference system, taken in a direction of the arrows as indicated by "3--3" in FIG. 2;
FIG. 4 is a section through the support assembly and particularly through a pivot joint of the outer support arm members of the support arms, showing details of the pivot joint; and
FIG. 5 is a partial schematic plan view of the extensible grade reference system showing alternate positions of a support arm member including a position for anticipatory grade change sensing in accordance with the invention.
DETAILED DESCRIPTION OF THE INVENTION
The Paver
Referring to FIG. 1, there is shown a bituminous paving machine or "paver", which is designated generally by the numeral 10. The paver 10 illustrated and broadly described herein is an example of apparatus to which the present invention advantageously applies and which is improved in its operation by features of the invention. The paver 10 includes generally a tractor unit 11 centrally through which dual feed conveyors 12 carry paving material, such as asphaltic material, from a feed hopper 13 located at the front of the paver 10 towards its rear. Spreader augers, also referred to as spreading screws 14, are disposed transversely to and at the rear of the tractor unit 11 adjacent rear portions of two parallel screed pull arms 15 the front ends of which are pivotally supported at respective pull points 16 on each side of the tractor unit 11. The spreading screws 14 distribute the asphaltic material transversely to the direction of travel of the tractor unit 11. The material is spread over the desired width of a strip of pavement 17 and is struck off at a desired level prior to being compacted. A surveyed grade reference, such as a string line 18 is typically stretched just outside of an outer edge or boundary 19 of the strip of pavement 17 to denote the specified grade of the pavement 17. The actual grade of the pavement 17 becomes established by a material-compacting, floating screed, a screed assembly being designated generally by the numeral 20. Consequently, the relationship of the height or vertical position of the bottom of the screed 20 with respect to the string line 18 establishes the correctness of the grade of the pavement 17. The screed 20 is attached to the rear of the pull arms. The angle at which the screed 20 floats on the asphaltic mix is, in addition to other slope adjustments of the screed 20, steadied and maintained by the angle of the pull arms 15. Other changes such as transverse slope changes in the screed 20 can be achieved by changing the angle of one side of the screed 20 with respect to the other. Such techniques are well known and are typically applied in paving operations. Because of the mounting of the screed 20 to the rear portions of the pull arms, the distance between the rear of the pull arms 15 and the bottom of the screed remains in theory fixed, and varies, for example, because of typical tolerances in the equipment, such as play in the pull arms 15 which play allows twisting about the longitudinal axes of the pull arms.
U.S. Pat. No. 4,702,642 to Musil pertaining to an extensible screed assembly, such as the screed assembly 20, describes in detail functions and the operation of such a screed assembly including adjustments to achieve various operating widths of the screed, as may be obtained by screed extensions 21, as shown in FIG. 1. As a result of width adjustments in the screeds for changing the width of the pavement 17, the distance of the string line 18 from the center of the intended pavement 17 is correspondingly extended to remain undisturbed by the paving operation. In further reference to FIG. 1, the positions of grade sensors 22 with respect to the paver 10 are similarly adjustably mounted to become located adjacent the string line 18 at various distances from a centerline 23 of the paver 10. An extensible grade reference system or grade sensor support structure 24, located at the rear of the tractor unit 11, provides the support for making adjustments to the grade sensors 22. Control over the operation of the paver 10 is typically exercised from a control console 25 which is typically located in the rear of the tractor 10 just ahead of the screed 20 and on either side of the centerline 23 of the paver 10. Screed controls are typically located directly on the screed 20 and are serviced by a person other than the person controlling the paver 10. In general, control tasks may include monitoring automatic grade reference controls. The controls also include steering controls and power controls regulating the forward motion of the paver 10. The paver 10 is typically powered by an engine 26 located along the centerline 23 of the paver 10 between the feed hopper 13 and the screed 20. In that screed control functions are typically semi-automatic or fully automatic, a primary control function is steering the paver 10 and monitoring contact by and proper adjustment of the grade sensors to the grade reference, such as the string line 18.
The Support Arm Assembly
To achieve adjustments of the sensors 22 into vertical alignment with the current location of the string line 18, the sensors 22 are pivotally mounted to outer ends of outer support arm members 28 and 29 of a support arm assembly 30, which outer support arm members 28 and 29 are themselves pivotally mounted at their respective inner ends. FIG. 1 shows a preferred arrangement and location of the support arm assembly 30 and the cooperative relationship of the components thereof. Right and left support arms 31 and 32 extend from right and left hand support tubes 33 and 34, respectively. The right support tube 33 is disposed above and offset toward the front of the paver 10 with respect to the left support tube 34. The support tubes 33 and 34 are disposed to preferably coincide with their respective lengths and are permanently joined to each other, such as by welding, so as to form a unitary structure referred to as support tube assembly 35. The offset disposition of the support tubes 33 and 34 does not affect the transverse adjustment range of the grade sensor 22. The resulting vertical offset between the right and left outer support arm members 28 and 29 can be compensated for as further explained below in reference to FIG. 2. Consequently, in spite of the offset disposition of the support tubes 33 and 34, the support arms 31 and 32 and the outer support arm members 28 and 29 may be of the same length and can be of reversible construction, if so desired. Outer support arm members 28 and 29 are pivotally attached at inner pivot ends 36 to respective outer ends 37 of the right and left support arms 31 and 32 to be preferably pivotable through an arc 38 of approximately a right angle in a substantially horizontal plane from an extended position transverse to the paver 10 to a fully pivoted position pointing forward in the direction of travel of the paver.
In designating structural members as right, left, front or rear members, it should be noted that these designations are made in reference to the forward direction of travel of the paver 10 as indicated by an arrow 40. In general, positioning adjustments of the support arm assembly 30 will be similar on both sides of the paver 10, unless reference to the string line 18 is made on only one side of the paver 10 and the elevation of the pavement on the other side is controlled by a typical slope controller. Differences in adjustments, as described with respect to the drawings, and alternate positions shown, illustrate ranges of possible adjustment and advantages derived thereby.
The support tubes 33 and 34 are preferred to be as long, or longer by only a nominal length for clearances and assembly tolerances, as a respective width across the pull arms 15. The support arm assembly 30 is mounted to the pull arms 15 in a centered position with respect to the paver 10, such that ends 41 of the support tubes 33 and 34 from which the respective support arms 31 and 32 extend are located just beyond the respective pull arms 15 Thus, when for example, the support arms 31 and 32 are fully retracted into the respective support tubes 33 and 34, the respective outer support arm members 28 and 29 may be pivoted forward for storage to become disposed adjacent and just to the outside of the pull arms 15, as shown by the forward pivoted position of the support arm member 29 in FIG. 1. In such a pivoted position of the outer support arm members 28 and 29, a grade reference directly adjacent the screed pull arms 15 may be also be sensed.
The manner in which the support arm assembly 30 of the preferred embodiment is mounted to the paver 10 is best described in reference to FIG. 2. Rear portions 42 of the pull arms 15 terminate in rear mounting plates 43 which are disposed substantially perpendicular to the lengths of the pull arms 15 Each of two L-shaped brackets or pivot arms 44 has at a forward end thereof a pivot arm mounting plate 45 which is rigidly attached to the respective pivot arm 44 perpendicular to the major surface thereof. The mounting plates 43 and 45 have aligned apertures 46 which permit the pivot arms 44 to be removably attached to the respective rear portions 42 of the pull arms 15. The removable attachment is achieved by inserting and fastening bolts 47 through the apertures 46 in a typical manner with appropriate mounting hardware 48 In the attached position the pivot arms 44 effectively become longitudinal extensions of the respective pull arms 15. The ability of detaching the pivot arms 44 from the pull arms 15 permits the removal of the screed 20 from the tractor unit 11 without the need to disassemble major portions of the screed 20. FIG. 2 further shows screed lift brackets 51 which have apertures 52 in alignment with the apertures 46 to become, in the described embodiment, sandwiched between the respective mounting plates 43 and 45. Each of the two screed lift brackets 51 has an apertured lift lug 53 as an integral part thereof. One end of a conventional lift device (not shown) such as a hydraulic cylinder or a screw jack may be attached to the lift lug 53 with the other end of the lift device being attached to the paver 10, to raise the screed 20 with respect to the paver 10 away from the surface of the pavement 17. Such lifting is convenient, for example, to maneuver the paver 10 from or into paving positions between paving operations. In a manner similar to the screed lift brackets 51, right and left support arm assembly mounting brackets 56 and 57 are sandwiched between the mounting plates 43 and 45 preferably ahead of the screed lift brackets 51. The mounting brackets 56 and 57 feature apertures 58 aligned with the apertures 46 in the respective mounting plates for admitting the bolts 47 therethrough. The mounting brackets 56 and 57 feature respectively inwardly extending mounting ears 59 and 60 along their upper edges 61. The ear 59 features a mounting aperture 62, while the ear 60 has a mounting slot 63 which is horizontally disposed with respect to the upper edge of the respective mounting bracket 57.
The lower, left support tube 34 of the support tube assembly 35 has right and left sets 64 and 65 of mounting lugs 66 welded to a lower edge 67 thereof. Each of the mounting lugs 66 holds a pivot bearing 68, each two of which in the respective set 64 or 65 are axially aligned, as shown in the sectional view of FIG. 3. The aligned pivot bearings 68 admit a mounting bolt 69 to mount the support arm assembly 30 to the mounting brackets 56 and 57 and, hence, to the pull arms 15. The bolt 69 is inserted through the pivot bearings 68 and through spacers 71 on either side of the respective mounting ear 59 or 60, as is shown in the sectional view with respect to the mounting ear 60. Two jam nuts 72 are threaded onto the end of the bolt 69 and are tightened against each other to hold the bolt snugly, yet not tightly. With the jam nuts 72 properly adjusted and tightened, the spacers 71 steady the support arm assembly 30 vertically on the mounting ears 59 and 60. Still, a sliding clearance allows the bolt 69 to slide within the slot 63 and the pivot bearings 68 to pivotally relieve bending-and transverse stresses. Such stresses would in case of a clamped mounting be transmitted to the support arm assembly 30 as the B result of twists or transverse movements of the pull arms 15. Such twists or transverse movements are likely to cause positional changes of the support arm assembly 30. Any positional changes would be amplified by the extending outer support arm members 28 and 29 and the grade sensors 22 mounted thereto, possibly causing unwanted screed adjustments and defects in the pavement 17. A snug but not tight adjustment of the nuts 72 on the mounting bolts 69 tends to minimize such stress transmission. On the upper surface of the upper, namely the right support tube 33 of the support tube assembly 35, a slope control mounting bracket 73 (see FIG. 2) provides an alternate attachment base as a possible mounting location, if so desired, for a slope sensor box (not shown). On prior art apparatus, such a slope sensor box is typically mounted on an overhead frame supported on both sides by respective screed pull arms.
It should be understood that the attachment of the support arm assembly 30 to the pull arms 15 by means of the sandwiched mounting brackets 56 and 57 represents a particular embodiment of the invention. Other mounting arrangements are contemplated, such as attaching mounting brackets with functions similar to the mounting brackets 56 and 57 to the top or to inner or outer surfaces of the pull arms 15. However, even when such changes are contemplated, a stress relieving mounting arrangement as described herein above is deemed desirable to achieve certain advantages of the preferred embodiment. The manner in which the support arm assembly 30 is supported vertically with respect to the pull arms 15 allows the outer support arm members 28 and 29 to pivot substantially in a horizontal plane. However, it should be realized that the orientation of such plane depends on the angle of the pull arms with respect to the horizontal. Under typical operating conditions the screed pull arms 15 are considered to be disposed substantially horizontal. Thus, when reference is made to the substantially horizontal plane through which the outer support arm members move, the orientation of the plane is understood to be in reference to the pull arms 15.
In reference to FIG. 2, the outer support arm members 28 and 29 carry at respective outer ends 76 and 77 support plates 78 rigidly mounted to clamping sleeves 79. The clamping sleeves 79 are slidably adjustable along the respective lengths of the support arm members 28 and 29 to be clamped rigidly into a desired position thereon. A standard grade sensor mounting assembly 80 is attached to the support plates 78. Typically, the sensor mounting assembly 80 includes a vertical sensor support 81 which supports at its lower end a horizontal sensor support 82. The vertical sensor support 81 typically includes vertical and vertically pivotal or axially rotational adjustment provisions with respect to the outer support arm member. Such provisions, shown as a jack screw 83 and releasable U clamps 84 in FIG. 2, permit the horizontal sensor support 82 to be adjusted for proper alignment of the grade sensor 22 such that a sensor element 85 of the sensor 22 becomes centered on the string line 18, as shown in FIG. 1. Precise inward or outward adjustments of the sensor element 85 are made possible, for example, by a corresponding extension or retraction of the horizontal sensor support 82, which adjustments are retainable by tightening of typical clamping screws 87, for example, which retain the sliding extension members 89 of the grade sensor mounting assembly 80.
Support Arm Extension
Each of the support tubes 33 and 34 has a clamping arrangement 90 of three clamping screws 91 which are located adjacent and at preferred spaced intervals inward from the open extension end 41 of the respective support tube 33 or 34. The outer cross-sectional shape of the support arms 31 and 32 is preferably complementary to the inner cross-sectional shape of the support tubes 33 and 34, though providing a sliding clearance between the respective outer and inner surfaces. In the preferred embodiment, the crosssectional shape of the support tubes 33 and 34 and the respective cross section of the support arms 31 and 32 are of square shape. The extension ends 41 slidingly receive inner end portions 92 of the support arms 31 and 32. While the clamping screws 91 are not tightened, the support arms 31 and 32 are freely adjustable inward and outward over the range described herein.
The clamping arrangement 90, once engaged, restrains the support arms 31 and 32 from further inward or outward movement, and also references the orientation of the support arms 31 and 32 with respect to the orientation of the support tubes 33 and 34. In the preferred embodiment, clamps 91 are spaced by a distance of six inches from each other. Also, the first one of the clamping screws 91 is set back from the respective end by some distance, for example three inches, allowing an effective clamping base for each clamping screw 91 of three inches to each side of the application point of the screw. Thus, each set of the three clamping screws 91 clamps down a length of approximately twenty four inches of the respective support arms 31 and 32.
As illustrated by the sectional view of FIG. 3, the clamping screws 91 are threaded into the respective support tube, such as shown with respect to the support tube 33 in FIG. 3, through standard threaded fasteners which are part of and held within nut cages 93. The nut cages 93 are welded to an edge 94 of the respective tube at a preferred angle of forty five degrees from the orthogonal axes of the support tube assembly 35. The clamping action described with respect to the support tube 33 and the right support arm 31 is also applicable to the left support tube 34 and the respective left support arm 32. When the clamping screws 91 are threaded into the tube 33 to engage the support arm 31 at the preferred angle, the resulting tightening force, resolved into horizontal and vertical force components 97 and 98, respectively, presses the support arm 31 against inner vertical and horizontal reference surfaces 101 and 102 of the respective tube 33. The respective support arms 31 or 32 are consequently supported rigidly over a base of twenty four inches, provided such a length of the support arms remain in engagement with the support tubes 33 or 34.
In regard to the amount of extension of the support arms 31 and 32, twenty four inches is preferred to be the minimum engagement distance of the support arms 31 and 32 with the support tubes 33 and 34. The described clamped distance provides the base for the extension of the support arms 31 and 32, the outer support arm members 28 and 29, and the respective grade sensor mounting assemblies 80 as described above. In a particular embodiment the support arms 31 and 32 have preferred lengths of 120 inches and the respective outer support arm members 28 and 29 have a preferred length of thirty six inches. A maximum contemplated extension of the support arms 31 and 32 is, consequently, approximately eighty percent of the length of the support arms. Extension of the support arms 31 and 32 is achieved by loosening the clamping screws 91, adjusting the length of extension of the support arms as needed and retightening the clamping screws. The support arms 31 and 32 are similarly easily retracted into the respective support tubes 33 and 34. The retraction of the support arms 31 and 32 stores the support arms, yet affords availability for any job of the paver that may require an extension of the grade sensors 22 outward from a close sensing position. An extension of the support arms 31 and 32 may be desirable even when no screed extensions are used. For example, surface interference may require a string line 18 temporarily to be placed further than normal from the paver 10.
The Outer Support Arm Member
FIG. 4 shows in greater detail a preferred pivotal hinging and position locking arrangement for the outer support arm members 28 and 29. Upper and lower pivot plates 103 and 104 are welded to the inner ends 36 of the arm members 28 and 29, the arm member 28 being shown in FIG. 4. Each of the pivot plates 103 and 104 has a pivot aperture at 106 and an arcuate pivot slot 107 with a center of curvature at the pivot aperture 106. The centers of the pivot apertures 106 on the plates 103 and 104 are in vertical alignment defining a vertical axis about which the arm members 28 and 29 will pivot. The corresponding support arm 31 has two through holes 108 adjacent its outer end 37 and transverse to the length of the support arm. The pivot aperture 106 and pivot slot 107 are aligned with the through holes 108 and bolts 109 extend therethrough to complete the attachment of the outer support arm members 28 and 29 to the support arms 31 and 32. The bolts are tightened with nuts 110. To adjust the angle of the support arm members 28 and 29, the bolts 109 are loosened and retightened after the adjustment. Tightening in particular the bolt 109 inserted through the pivot slot 107 locks in the pivotal adjustment of the outer support arm member.
In a paving operation, the outer support arm members 28 and 29 carrying the grade sensor mounting assemblies 80 may be pivoted from a forward, stored position to a partially extended position, such as, for example, through a pivot angle of forty five degrees from the forward position, to align the grade sensor 22 with the grade reference, such as the string line 18 as described above. The length of the outer support members of thirty six inches is preferred, in that a pivoted position provides substantially for a full extension of the support arm assembly 30 and still provides for a forward positioning of the sensor 22 for an anticipatory grade change indication.
FIG. 5 illustrates an adjustment support arm assembly 30 to increase or decrease the responsiveness of the grade sensors 22 to anticipatory grade changes. In a first adjusted position of the support arm assembly 30 the outer support arm member 29 is pivoted transversely to the direction of travel of the paver 10. The grade sensor mounting assembly positions the sensor 22 substantially at the leading edge 111 of the screed 20, at which the sensor element 85 will be adjusted to a fixed distance above the base of the screed. Thus in the extended position, the sensor element will be insensitive to changes in the angle of the pull arms 15. Such changes may occur from inaccuracies in the pavement base or as a result of the grade of the base having changed because of an upcoming grade change. In case of inaccuracies it is desirable to correct the angle of the pull arms 15 before the floating screed changes the grade angle in the direction of travel of the paver. Because of the floating characteristic of the screed 20, such a grade angle change would typically precede an actual grade change. By the time the grade sensor 22, located directly at the screed senses a deviation of the screed 20 with respect to the string line 18, the screed may already be well into a grade change. Even though corrective adjustments may bring an immediate return of the screed level with respect to the string line 18, the imperfection already may have been embedded into the pavement 17.
The alternate position of the outer support arm member 29, pivoted about axis 112, positions the grade sensor 22 toward the front of the tractor unit 11 and away from the leading edge of the screed 20. The alternate position consequently decreases the responsiveness of indication to the grade of the screed 20 with respect to the grade reference, such as the string line 18, but causes instead the grade sensor 22 to register changes in the angle of the pull arms 15 as deviations of the screed 20 away from the string line 18, even though at that moment the screed may still be at an ideal grade level with respect to the string line 18. The registered deviation is used by typical state of the art pavers to effect an angle correction of the pull arms 15 in a direction to maintain the current grade being paved by the screed 20. On the other hand, when a grade change occurs, before the screed 20 adjusts to the new grade, the angle of the screed needs to change correspondingly. Because of the width of the base of the floating screed 20, the screed needs to have moved at least some distance past the current paving position before the angle of the screed 20 can have changed. An anticipatory grade change, sensed by the forward, alternate position of the sensor 22, permits such a change in the angle of the screed in time that the pavement is compacted at the changed angle when the screed 20 has reached the forward position of the string line or other grade reference at which the change in grade was first detected.
The support arm assembly 30 provides for an adjustment range of approximately the length of the outer support arm members 28 and 29 to determine an optimum forward adjustment position for the grade sensor 22 to provide a mix of anticipatory grade control indications in conjunction with the grade reference indications for an optimum adjustment of the smoothness of the pavement 17.
The above description of the invention in reference of a preferred embodiment thereof does bring to mind various changes and modifications possible without departing from the spirit and scope of the invention. It should be realized, for example, that an extensible grade reference system, such as disclosed herein, is frequently used only on one side of a paving machine. Consequently, a structure which provides an extensible grade reference system to only one side of a paving machine may still be considered to lie within the scope of the present invention. It is also expected, that various models and makes of pavers similar to the paver 10, yet differing in structural details, may require a mounting structure which differs somewhat from the structure for mounting the support tube assembly 35. Instead of employing sandwiched support arm assembly mounting brackets 56 and 57, brackets including ears, similar to the ears 59 and 60 may be permanently or removably mounted to the tops or sides of pull arms. Also, various grade references are used and grade sensors change accordingly. The extensible grade reference sensor mounting structure may consequently include any of various sensors for sensing string lines or direct grades without affecting the spirit and scope of the invention.
Other changes and modifications are possible within the spirit and scope of the claimed invention.
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A paver of the floating screed type which is capable of operating with screed extensions for laying down pavement at various widths includes a self-contained, stowable and extensible grade reference system with a wide, planar adjustment range. The grade reference system provides an adjustment range for positioning a grade sensing device on either or both sides of the paver both forward and transversely outward from a selected support point on the paver. The grade reference system has a pivotally outer support member which permits the sensing device to become positioned at any selected setting of an arcuate path forward of a rearward position in substantial alignment with the leading edge of the screed to a forward position determined by the length of the member. The pivotal adjustment range of the outer support member is augmented by a transverse adjustment range effected by an extension or retraction of a corresponding support member to shift the pivot axis of the outer support member respectively outward or inward. The combination of the two adjustments provides for a mix of anticipatory grade change sensing combined with laterally outward extensions of the screed beyond the full extension range of the screed.
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CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This is a United States Nationalization of PCT Application PCT/EP2008/059829 filed Jul. 25, 2008 which in turn claims priority from German Patent Application 10 2007 035 417.9 filed Jul. 28, 2007.
BACKGROUND OF THE INVENTION
[0002] Thermoplastic polymers, including thermoplastic elastomers, are used in many fields, for example in the electrical and electronics field, in the construction field, in building technology, in automotive production and in public transport vehicles. They have advantageous mechanical properties and good processability and chemical stability. One possible way of making such polymers flame resistant is the addition of halogen-containing flame retardants with antimony trioxide. A further possibility is the addition of halogen-free substances such as metal hydroxides, organic or inorganic phosphates or phosphonates, for example ammonium polyphosphates, together with synergistically active substances such as carbon sources and blowing agents.
[0003] The halogen-free flame retardants in particular are gaining increasing importance since in contrast to flame retardants which contain chlorinated or brominated organic compounds, they cause less fume evolution in case of fire and are as a rule classified as environmentally friendly. Among the fire retardant substances, derivatives of phosphoric acid, pyrophosphoric and the polyphosphoric acids are mainly used in halogen-free flame retardants. Ammonium and melamine derivatives of the aforesaid substances and piperazine phosphate and ethylenediamine phosphate have the property that when they are incorporated in moulding compositions they swell into voluminous protective layers at high temperatures and act as an insulating layer against a heat source. This property can be further reinforced by synergistically active substances. In contrast to the mode of action of halogen-containing flame retardants, the swelling, so-called intumescence, takes place without the evolution of substantial quantities of fumes.
[0004] The use of the aforesaid flame retardants in polyolefins often does not provide sufficient protection and in addition synergistically active substances such as for example carbon sources and blowing agents must be added. In order to ensure adequate effectiveness of such flame retardant compositions, a very high proportion of flame retardant must often be added to the polymer, which leads in particular to alteration of the mechanical and electrical properties of the polymer.
[0005] The previously particularly effective flame retardants include mixtures of ammonium polyphosphate with amines, such as for example mixtures with melamine compounds and/or pentaerythritol. Further well-known intumescent mixtures are based on ammonium polyphosphates in combination with THEIC (1,3,5-tris-hydroxyethylisocyanuric acid).
[0006] However the disadvantage of these mixtures consists in the fact that even after introduction into a polymer they display very high water solubility so that they are partially leached out and consequently their effect can no longer be obtained. Furthermore they have a low decomposition temperature, which already to some extent leads to decomposition of the flame retardant additive during the moulding of the plastic objects from the polymer to be protected. Furthermore in spite of improved effectiveness these mixtures must be used in high concentrations in a polymer as a result of which the processability and flexibility of the polymer is decreased.
BRIEF SUMMARY OF THE INVENTION
[0007] In the light of this background, the purpose of the invention is to provide a polymeric material which has a halogen-free flame retardant incorporated into the polymer matrix, in which the halogen-free flame retardant has improved flame resistant action compared to the state of the art, is usable in smaller concentrations in a polymeric material while at the same time having good flame resistant action, has low water solubility, and only decomposes at higher temperatures than known flame retardants, preferably above the processing temperature of the polymers, and the polymeric material has good material properties, good flame resistance and at the same time good water resistance.
[0008] According to the invention, the problem is solved by a polymeric material which has a halogen-free flame retardant incorporated into the polymer matrix, wherein the flame retardant contains at least the following components A and B:
[0000] A. ammonium polyphosphate(s) and/or derivatives thereof,
B. an oligomeric or polymeric 1,3,5-triazine derivative or mixtures of several thereof of the general formula
[0000]
[0000] wherein X is a morpholino residue, a piperidino residue or a group derived from piperazine,
Y is a divalent group derived from piperazine and
n is a whole number greater than 1,
and at least one compound selected from the following components C and D:
C. phosphates, pyrophosphates, polyphosphates, organic and inorganic phosphonates, organic and inorganic phosphinates, stannates, molybdates or borates of the elements of the main groups II, III or IV or the transition group elements Fe, Zn, Ti, Mn, Zr and Mo,
D. precondensed melamine derivatives, melamine salts and adducts, ethylenediamine phosphate, piperazine phosphate, piperazine polyphosphate, 1,3,5-trihydroxyethyl isocyanurate, 1,3,5-triglycidyl isocyanurate and triallyl isocyanurate,
[0009] wherein the weight ratio of the component A to the component B is from 10:1 to 1:1 and the components A and B together make up 60 to 99 wt. % and the components C and D together make up 1 to 40 wt. % of the total weight of the components A, B, C and D, and
[0010] wherein the polymeric material is a thermoplastic elastomer (TPE).
DETAILED DESCRIPTION OF THE INVENTION
[0011] In one embodiment of the invention, the polymeric material contains the halogen-free flame retardant in a quantity of 5 to 60 wt. %, preferably in a quantity of 10 to 40 wt. %. Component A includes both coated and also uncoated ammonium polyphosphate(s) and/or derivatives thereof.
[0012] Here the term “coated ammonium polyphosphates” includes both simply coated ammonium polyphosphate and also coated and crosslinked ammonium polyphosphate. The effect of such a coating is that, in contrast to uncoated ammonium polyphosphate, on addition of the flame retardant to a polymer it results in increased thermal stability, lower water solubility and improved compatibility with the polymer matrix in which the flame retardant is used. The component A is obtainable by coating of a powder or granules of ammonium polyphosphate or a derivative thereof.
[0013] The component A is added to the flame retardant as a powder or granules and in the event of a fire produces markedly fewer fumes than halogen-containing flame retardants.
[0014] Component B is an oligomer or polymer of a 1,3,5-triazine derivative or a mixture of several thereof, and it is a substance also having flame retardant action in combination with phosphates. Component B is decomposed by the action of intense heat or contact with a flame, with the generation of non-inflammable gases, including water, carbon dioxide, ammonia and nitrogen, with formation of a carbon-containing residue. The component B acts as a carbon source in the intumescent mixture according to the invention.
[0015] The weight ratio of the components A and B of 10:1 to 1:1 results in optimal flame resistant action. A lower or higher proportion of the component B would decrease the effectiveness of the flame retardant. In this connection the weight ratio of the component A to the component B is preferably from 6:1 to 2:1 and particularly preferably from 5:1 to 3:1.
[0016] Further it is preferable if the components A and B together make up from 85 to 99 wt. % and particularly preferably from 90 to 95 wt. % and the components C and D together preferably make up from 1 to 15 wt. % and particularly preferably from 5 to 10 wt. % of the total weight of the components A, B, C and D.
[0017] Component C contains substances, in particular salts, which in the flame retardant according to the invention cause a further reduction in the evolution of fumes. As a result, the toxicity caused by fumes during fires is markedly reduced and at the same time the action of the flame retardant is improved. In addition, this component results in higher efficiency of the flame retardant and improved mechanical properties of the polymer in which the flame retardant is used.
[0018] Component D contains precondensed melamine derivatives and/or melamine salts and adducts, ethylenediamine phosphate, piperazine phosphate, piperazine polyphosphate, 1,3,5-trihydroxyethyl isocyanurate, 1,3,5-triglycidyl isocyanurate, triallyl isocyanurate or mixtures thereof. Examples of precondensed melamine derivatives are melem, melon, melam, melamine cyanurate, melamine borate, melamine orthophosphate, melamine pyrophosphate, dimelamine pyrophosphate and melamine polyphosphate.
[0019] The compounds of the component D act as blowing agents. The precondensed melamine derivatives and/or melamine salts and adducts are so stable that during the processing of a plastic which contains the flame retardant no condensation reaction or decomposition reaction takes place and as a result the processability of the plastic is considerably improved. At the same time the flame retardant action is retained.
[0020] The compounds of the component D have a decomposition temperature comparable with or higher than that of ammonium polyphosphate and therefore reinforce the efficacy of the ammonium polyphosphate or derivatives thereof. On use in a plastic, the stability, process-ability and mechanical strength thereof are maintained.
[0021] The components of the flame retardant according to the invention in the composition according to the invention also contribute to the improvement of the mechanical properties of a polymer in which the flame retardant is used.
[0022] A further advantage of the flame retardant according to the invention is that in comparison to conventional flame retardants it can be used in smaller quantities with equally good or better action and as a result the costs of a plastic thus treated are also reduced and the mechanical properties thereof are less strongly influenced or impaired. Even at a concentration of less than 30% in a thin film plastic, the flame retardants according to the invention achieve a very good flame retardant action.
[0023] Preferably the component A is or contains coated ammonium polyphosphate and/or derivatives thereof. The coating of the component A effects not only a marked reduction in the water solubility, but also increased temperature stability of the ammonium polyphosphate, reduced reactivity of the ammonium polyphosphate with other components of the flame retardant and increased compatibility with the polymer in which the flame retardant is used.
[0024] According to one embodiment the component A in the flame retardant according to the invention is selected from coated ammonium polyphosphates of the crystal forms I, II or V or mixtures thereof.
[0025] Particularly preferably, component A contains coated and/or uncoated ammonium poly-phosphate of the crystal form II, which compared to the other crystal forms is almost insoluble in water. This is a powdery substance which has a good flame retardant action at the same time as low water solubility even without coating. The advantage of the use of coated ammonium polyphosphate of the crystal form II consists in the fact that this has higher thermal stability and higher compatibility with polymers, so that as a result improved dispersion of the flame retardant in the polymer, an improved processing profile of the polymer and more efficient fire protection are achieved.
[0026] Preferably here the ammonium polyphosphate and/or derivatives thereof is/are coated with melamine, melamine resin, melamine derivatives, silanes, siloxanes or polystyrenes. An ionic bond is formed between the particulate ammonium polyphosphate and/or derivative thereof and the coating material, during which the ammonia bound to the ammonium polyphosphate is replaced by the coating material. This bond is very stable so that during the processing of the plastic the coating is largely stable.
[0027] The production of melamine-coated ammonium polyphosphate is effected at temperatures of more than 250° C. Here, the reaction time is designed such that any excess melamine completely reacts with the surface of the ammonium polyphosphate, replaces ammonia in the process and is bonded better.
[0028] Also preferred is the coating of the ammonium polyphosphate particles with melamine, melamine resin, melamine derivatives, silanes, siloxanes or polystyrenes, followed by crosslinking. The crosslinking of the melamine coating effects a further reduction in the water solubility of the ammonium polyphosphate and is as a rule performed with formaldehyde. The process is known to the person skilled in the art.
[0029] Preferably, the content of the coating of the ammonium polyphosphates and/or of the derivatives thereof is 0.1 to 20 wt. %, preferably 1 to 10 wt. %, based on the total weight of the coated ammonium polyphosphates and/or of the derivatives thereof. With such a ratio of ammonium polyphosphate to coating, optimal protection of the ammonium polyphosphate is ensured, which also leads to optimal combinability of the ammonium polyphosphate with a polymer in which the flame retardant is to be used. At the same time with this ratio the coating is not present in such an excess that detachment of free coating material which is less strongly bound to ammonium polyphosphate takes place.
[0030] Particularly preferably, the average particle size D50 of the coated particles of ammonium polyphosphate or a derivative thereof is from 5 μm to 30 μm, in particular from 5 μm to 20 μm and particularly preferably between 7 μm and 18 μm, including the coating. Larger particles cannot be sufficiently homogeneously dispersed in a polymer and would as a result under some circumstances adversely affect its properties. Smaller particles are likewise less preferred, since they are difficult to meter.
[0031] In the coated ammonium polyphosphate and/or derivative thereof the average particle size D50 of the particles of ammonium polyphosphate and/or of the derivatives thereof as the core of the coated particles is preferably about 7 μm. Also achieved thereby in particular is that the flame retardants according to the invention display higher decomposition temperatures and hence very high temperature stability in comparison to previously known flame retardants.
[0032] As component B, an oligomeric or polymeric 1,3,5-triazine derivative wherein n is a whole number from 2 to 50, particularly preferably from 2 to 30 and especially preferably from 3 to 9, is preferably used. In the production of such oligomers or polymers, mixtures of different chain lengths are usually formed. Such mixtures arising during the polymerisation, wherein more than 70%, preferably more than 80%, and particularly preferably more than 90% of the oligomers and polymers used have a chain length of n=2 to 50, preferably of n=2 to 30 and particularly preferably of n=3 to 9, can also be used. Both heteropolymers and also homopolymers can be used here.
[0033] Preferred monomers of the 1,3,5-triazine derivative as in component B are 2-piperazinylene-4-morpholino-1,3,5-triazine and 2-piperazinylene-4-piperidino-1,3,5-triazine. Mixed oligomers or polymers of the aforesaid substances can also be used. The synergistic effect of the said polymers or oligomers with coated ammonium polyphosphate and/or derivatives thereof in particular effects an increase in the efficiency of the flame retardant.
[0034] Preferred compounds as in component C which further improve the effectiveness of the flame retardant and in particular enable addition of a smaller quantity of the flame retardant are metal salts, in particular monozinc phosphate Zn(H 2 PO 4 ) 2 , zinc borate, trizinc phosphate Zn 3 (PO 4 ) 2 , zinc pyrophosphate Zn 2 P 2 O 7 , zinc polyphosphate of the general formula oZnO pP 2 O 3 qH 2 O, wherein o and p are from 1 to 7 and q is from 0 to 7, zinc hydroxystannate ZnSn(OH) 6 , zinc stannate ZnSnO 3 , boron phosphate BPO 4 , monoaluminium phosphate Al(H 2 PO 4 ) 3 , trialuminium phosphate AlPO 4 , aluminium metaphosphate [Al(PO 3 ) 3 ] n , ammonium octamolybdate (AOM) and mixtures thereof. With these salts in particular it has surprisingly been found that through the interaction with the components A and B outstanding action of the flame retardant is achieved, which even with a small added quantity in polymers leads to classification in the highest fire retardancy class.
[0035] Among the precondensed melamine derivatives, melamine salts and melamine adducts of the component D, melem, melon and melam are preferred. Further preferred compounds of the component D are melamine cyanurate, melamine borate, melamine orthophosphate, melamine pyrophosphate, dimelamine pyrophosphate and melamine polyphosphate. The addition of these substances effects a further improvement in the flame retardant, with these substances in small quantities also acting as blowing agents.
[0036] The polymeric material according to the invention is a thermoplastic elastomer which preferably contains the flame retardant according to the invention in a quantity of 5 to 60 wt. %, particularly preferably in a quantity of 10 to 40 wt. %. Even with low film thicknesses of e.g. only 0.8 mm, such flame-retarded polymers fulfil the highest fire protection requirements even with highly inflammable plastics. At the same time by means of the flame retardant according to the invention the flexibility and processability of the flame retardant treated plastics is improved compared to known plastics treated with flame retardants.
[0037] Preferred polymeric materials, namely thermoplastic elastomers, are selected from filled and unfilled olefin-based thermoplastic elastomers (TPO), crosslinked olefin-based thermoplastic elastomers, urethanes (TPU), polyesters and co-polyesters (TPC), styrene block copolymers (TPS) and polyamides and co-polyamides (TPA). In particular in the use of the flame retardant according to the invention with olefin-based thermoplastic elastomers, crosslinked olefin-based thermoplastic elastomers and styrene block copolymers, the mechanical properties of the plastics, in particular their abrasion resistance, are favourably influenced. Hence such flame retardant treated thermoplastic elastomers can in particular be used as a substitute for PVC in cables, wiring systems, tubes for electric cables and the pipework of wastewater systems. Particularly preferably, the thermoplastic elastomer according to the invention is selected from styrene block copolymers (TPS), preferably from the styrene block copolymers SBS (styrene-butadiene-styrene), SEBS (styrene-ethene-butene-styrene), SEPS (styrene-ethene-propene-styrene), SEEPS (styrene-ethene-ethene-propene-styrene) and MB S (methacrylate-butadiene-styrene).
[0038] Thermoplastic elastomers, in particular styrene block copolymers, are relatively readily inflammable, as a rule more readily than many other types of polymer, inter alia because they contain a high proportion of oils which increase the inflammability. It was therefore particularly surprising that thermoplastic elastomers could be flame retarded at all and in particular as effectively as is achieved according to the invention with the flame retardants according to the invention. Admittedly the proportion of flame retardant in the polymer matrix necessary for achieving good flame retardant action is as a rule somewhat higher than with some other types of polymer, however for very many types of thermoplastic elastomer this higher proportion of flame retardants does not adversely affect the mechanical and other properties significantly.
[0039] Further, apart from the flame retardant according to the invention, the polymeric material preferably contains other fillers which are selected from calcium carbonate, silicates such as talc, clay or mica, silica, calcium and barium sulphate, aluminium hydroxide, glass fibres and glass beads and also wood flour, cellulose powder and soots and graphites. These fillers can impart other desired properties to the plastics. In particular the price of the plastic can be decreased thereby, and the plastic can be coloured or desired mechanical properties of the plastic can be improved, e.g. by reinforcement with glass fibres.
[0040] In a further embodiment of the polymeric material according to the invention, the component B in the halogen-free flame retardant has a chlorine content of <1 wt. %, preferably <0.8 wt. %. This is particularly advantageous compared to the state of the art, since with known flame retardants undesirably large quantities of chlorine are introduced in the form of inorganically and organically bound chlorine.
[0041] In a further embodiment of the invention, the polymeric material overall has a chlorine content of <1500 wt. ppm, preferably <900 wt. ppm. This is particularly advantageous compared to the state of the art, since with known flame retardants undesirably large quantities of chlorine were introduced in the form of inorganically and organically bound chlorine. The term “halogen-free” in the sense of the invention allows low levels of chlorine impurities in the aforesaid maximum quantities. However, chlorine or halogen in general should generally be kept low, in order to avoid the adverse effects of the halogens.
[0042] In a further embodiment of the polymeric material according to the invention, dispersion aids are contained in the halogen-free flame retardant in a quantity of 0.01 to 10 wt. %, preferably in a quantity of 0.1 to 5.0 wt. %, the dispersion aids preferably being selected from fatty acid amides, including fatty acid monoamides, fatty acid bisamides, and fatty acid alkanolamides such as oleamides and erucamides, from fatty acid esters, including glycerine esters and wax esters, from C16 to C18 fatty acids, from fatty acid alcohols, including cetyl and stearyl fatty acid alcohols, from natural and synthetic waxes, polyethylene waxes and oxidised polyethylene waxes and from metal stearates, preferably Ca, Zn, Mg, Ba, Al, Cd and Pb stearates. The addition of the aforesaid dispersion aids improves the meterability of the flame retardant, the extrudability of the polymeric material and the homogeneity of the dispersed flame retardant within the polymer matrix.
[0043] In a further embodiment of the polymeric material according to the invention, the halogen-free flame retardant has a free water content (moisture content) of <0.6 wt. %, preferably <0.4 wt. %. A low water content also improves the meterability of the flame retardant, the extrudability of the polymeric material and the homogeneity of the dispersed flame retardant within the polymer matrix.
EXAMPLES
[0044] Some examples are presented below, which include both polymers according to the invention and not according to the invention, and the flame retardants used therein.
[0045] For the examples, test pieces for various tests were prepared in a Brabender plastic kneader. For this, a polymer with no added flame retardant was first melted with stirring. Next, the components A and B, and C and/or D were added to the melt in one step as a mixture or consecutively. After a homogenisation phase of 10 to 15 minutes, the plastic material was removed and pressed into plates with thicknesses of 0.8 mm and 1.6 mm by means of a heatable press. The pressed plates were cut into suitable test pieces using a saw and subjected to the tests described below.
[0046] The compositions of the different test pieces or comparison test pieces are given below in table form. The triazine derivative used is a polymer of 2-piperazinylene-4-morpholino-1,3,5-triazine. Further, an uncoated ammonium polyphosphate (FR CROS 484), a melamine-coated ammonium polyphosphate (FR CROS C40) or a melamine-coated and crosslinked ammonium polyphosphate (FR CROS 498) was used (Manufacturer: Chemische Fabrik Budenheim in each case). As melamine polyphosphate, Budit 3141 (Manufacturer: Budenheim Iberica) or Melapur 200 (Manufacturer: CIBA) were used. The aluminium phosphate used is Fabutit (Manufacturer: Chemische Fabrik Budenheim), and the melamine cyanurate is obtainable from Budenheim Iberica as Budit 315.
[0047] The examples designated only by a number and with no V are examples according to the invention. The examples identified by V and a number are comparison examples not according to the invention.
UL94 Vertical Test
[0048] To carry out the UL94 vertical test, referred to below as UL94 V, sets of five test pieces each with a thickness of 1.6 mm or 0.8 mm were clamped in a vertical position at one end. A Bunsen burner flame was held at the free end of the test piece twice for 10 seconds.
[0049] After this, the time to extinction of the flame or glowing of the test piece was measured in each case. At the same time it was noted whether ignited drops of the test piece could ignite cotton lying under it.
[0050] In each case, “TBT” indicates the sum of the burn times of a total of five test pieces in seconds.
[0051] The tests were performed in accordance with the instructions of Underwriter Laboratories, Standard UL 94V. “UL94” indicates the fire retardancy classification of the test piece, V0 meaning that the total burn time of five tested test pieces was less than 50 seconds and cotton was not ignited by glowing or burning components of the test piece dropping down. The classification V2 means that the total burn time of five tested test pieces together was less than 250 seconds, however a cotton cloth was ignited by test piece components dropping down.
LOI Test
[0052] The lowest oxygen concentration in an N 2 /O 2 mixture at which a sample just still continues to burn alone after ignition is the LOI value (limiting oxygen index). The higher the LOI value, the more flame resistant the sample. Here LOI values over 30% are very good. A high LOI is particularly important for complying with standards which are required in the cable industry.
[0053] The test was performed in accordance with DIN EN ISO 4589 part 2. The test pieces were of size 1.25 mm×3.0×6.5 mm.
[0054] Its of the tests are reproduced below in table form. The LOI is stated in percent.
Testing of the Decomposition Temperature of the Flame Retardant
[0055] As a further test, various flame retardant compositions were heated alone without incorporation into a polymer, and the temperature from which decomposition takes place was noted. The decomposition temperature is usually stated as the temperature at which a weight loss of 2% occurs.
[0056] These tests were performed by thermogravimetry. For this in each case a quantity of 10 mg of a flame retardant was placed in a crucible and heated to temperatures over 350° C. at a temperature increase rate of 10 Kelvin/min. During the heating, the weight change of the sample was measured.
[0057] The results of these tests are reproduced below in table form.
[0058] Particuarly with test pieces with film thicknesses of 0.8 mm, it is clear that the polymers containing flame retardants according to the invention achieve a marked improvement compared to the comparative examples with similar previously used flame retardants. Polymeric materials according to the invention almost all reach the highest fire classification of V0 in the UL 94 test at a film thickness of 0.8 mm, while this is not the case for the comparison examples.
[0059] In particular the attainment of the highest fire retardancy classification at very low film thicknesses and a low flame retardant content and a good fire retardancy classification opens up the possibility of flame retardant treatment of thermoplastic elastomers with very low film thicknesses, and thereby opening up new possible applications of halogen-free intumescent fire retardants. These include coverings of cables, cable ducts, sheeting, electronic components, housings for electrical and electronic devices, etc. Furthermore, in the production of such materials it is advantageous that the flame retardants according to the invention achieve excellent effects in the thermoplastics used and as a result the mechanical properties of the polymers thus treated remain unchanged. The flame retardants according to the invention are also characterised by very low fume evolution.
[0060] All the flame retardants according to the invention or polymers treated with flame retardants according to the invention and thus polymers according to the invention have both a very short burn time and also a very high oxygen index and a very high decomposition temperature. In addition, the polymers are processable so that replacement of environmentally harmful PVC with polymers according to the invention is possible.
[0000]
TABLE 1
Compositions
Example No.
Component
1
2
3
4
5
6
7
8
9
10
11
V1
V2
V3
V4
V5
V6
A
FR CROS 489
34
34
34
34
34
34
34
34
34
34
A
FR CROS C 40
34
20
A
FR CROS 484
34
B
triazine compound
8
8
8
8
8
8
8
8
8
8
8
5
X
pentaerythritol (comparison)
8
C
zinc pyrophosphate
1.5
C
zinc borate
1.5
C
aluminium phosphate
1.5
D
melamine cyanurate
3
3
3
3
3
1.5
1.5
1.5
3
D
melem
3
D
melon
3
D
melamine polyphosphate
3
Additive
magnesium hydroxide
45
55
45
45
Plastic
TPS
55
55
55
55
55
55
55
55
55
55
55
45
Plastic
TPA
55
55
Plastic
TPO
55
55
Plastic
PP
75
Plastic
HDPE
TPS: SEBS = styrene-ethylene-butylene-styrene
TPA: polyether polyamide block copolymer
TPO: thermoplastic polyolefin with non-crosslinked elastomer phase
PP: polypropylene
HDPE: high density polyethylene
[0000]
TABLE 2
Results of fire retardancy tests
Example No.
Test
Film thickness
1
2
3
4
5
6
7
8
9
10
11
V1
V2
V3
V4
V5
V6
TBT
1.6 mm
15
11
22
16
19
16
17
16
14
13
13
25
>50
>50
>50
>50
>50
UL 94
1.6 mm
V0
V0
V0
V0
V0
V0
V0
V0
V0
V0
V0
V0
V2
V2
V1
V2
V2
TBT
0.8 mm
25
22
>50
>50
30
28
30
29
26
25
26
>50
>50
>50
>50
>50
>50
UL 94
0.8 mm
V0
V0
V2
V2
V0
V0
V0
V0
V0
V0
V0
V2
n.c.
n.c.
n.c.
n.c.
n.c.
LOI
1.25 mm
31
32
28
29
31
30
31
31
34
33
33
32
21
25
27
25
27
n.c. = not classifiable (worse than V2)
[0000]
TABLE 3
2% weight loss of flame retardant (with no plastic)
Example No.
1
2
3
4
5
6
7
8
9
10
11
V1
V2
V3
V4
V5
V6
Temperature in ° C.
312
319
313
n.t.
n.t.
n.t.
n.t.
n.t.
n.t.
n.t.
n.t.
319
280
315
n.t.
n.t.
n.t.
n.t. = not tested
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The invention relates to a polymer material comprising a halogen-free flame-proofing agent incorporated into the polymer matrix, the flame-proofing agent comprising at least ammonium polyphosphate(s) and/or derivatives thereof and an oligomer or polymer 1,3,5-triazine derivative or mixtures of a plurality thereof and at least one compound selected from phosphates, pyrophosphates, polyphosphates, organic and inorganic phosphonates, organic and inorganic phosphinates, stannates, molybdates or borates of the elements of the main groups II, III, IV or of the sub-group elements Fe, Zn, Ti, Mn, Zr, Mo, pre-condensed melamine derivatives, melamine salts and addition compounds, ethylene diamine phosphate, piperazine phosphate, piperazine polyphosphate, 1,3,5-trihydroxyethyl isocyanurate, 1,3,5-triglycidyl isocyanurate and triallyl isocyanurate. The weight ratio of constituents A to constituents B is 10:1 to 1:1, constituents A and B together amounting to between 60 and 99 wt. % and constituents C and D to between 1 and 40 wt. % of the total weight of constituents A, B, C and D. The polymer material is a thermoplastic elastomer (TPE).
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to noise elimination methods and transmission circuits for eliminating a crosstalk noise which is generated among a plurality of signal lines, and more particularly to a noise elimination method and a transmission circuit which eliminate a far-end crosstalk noise of a bus transmission by inserting a terminating resistor which has a specific value at a far-end.
2. Description of the Related Art
In electronic equipments such as personal computers, signal transmissions among LSI circuits in most cases are made in units of 32 bits or 64 bits. In such signals, a plurality of bits make transitions at the same timing, thereby causing signal interference among the bits and in many cases generating the crosstalk noise. The value of this crosstalk noise becomes larger as the number of signals which make the transitions simultaneously becomes larger. In addition, the crosstalk noise becomes a large value even in the case of a short line as the signal rise/fall time becomes shorter.
FIGS. 1A and 1B are diagrams for explaining a backward near-end crosstalk for explaining a background of the present invention. FIG. 1A shows a driving line 80 , a driver 81 , a receiver 82 , a passive line 90 , a driver 91 , and a 35 receiver 92 . FIG. 1B additionally shows an internal resistance 83 of the driver 81 , a terminating resistor 84 , an internal resistance 93 of the driver 91 , and a terminating resistor 94 for the case shown in FIG. 1 A.
In a case where two lines on which the signal transmitting directions are opposite to each other as shown in FIG. 1A, the backward near-end crosstalk refers to the noise which is introduced on the passive line 90 near the driver 81 due to the signal on the driving line 80 .
FIG. 2 is a diagram showing the magnitude of the backward near-end crosstalk which is introduced in the transmission circuit shown in FIGS. 1A and 1B. In FIG. 2, it is assumed that an internal resistance 83 of the driver 81 has a value r=10Ω, and a resistance R of the terminating resistor 84 is infinitely large. In FIG. 2, the ordinate indicates the magnitude of the voltage, and the abscissa indicates the time. In FIG. 2. a thin solid line v 1 (near) indicates a voltage change on the driving line 80 on the side of the driver 81 (near-end), a thin dotted line v 1 (far) indicates a voltage change on the driving line 80 on the side of the receiver 82 (far-end), a bold solid line v 2 (near) indicates a voltage change on the passive line 90 on the side of the driver 91 (near-end), and a bold dotted line v 2 (far) indicates a voltage change on the passive line 90 on the side of the receiver 92 (far-end).
The backward near-end crosstalk becomes a considerably large value when the value r of the internal resistance 83 of the driver 81 is sufficiently small compared to the characteristic impedance of the passive line 90 . For this reason, the value r of the internal resistance 83 is conventionally set large so as to eliminate the backward near-end crosstalk noise.
The terminating resistor 94 is provided to make a waveform matching with respect to the output signal, and the resistance of this terminating resistor 94 is set to a value approximately equal to the characteristic impedance of the passive line 90 .
In other words, in a case where the characteristic impedance of the line is 50Ω, the terminating resistor 94 is set to approximately 50Ω.
Conventionally, when signals are transmitted on a plurality of lines in the same direction, no measures were taken with respect to the noise generated at the far-end on the opposite end from the driving side (hereinafter referred to as a forward far-end crosstalk noise) because the amplitude (voltage) of the forward far-end crosstalk noise is small compared to the backward near-end crosstalk noise and the effects of the forward far-end crosstalk noise with respect to the transmission line are small.
Although no measures are conventionally take with respect to the forward far-end crosstalk noise, there is a tendency for the physical distance among the signals to become smaller, due to the increased operation speed of the circuits and the reduced size and weight of the equipments. As a result, there is a tendency for the crosstalk noise to be generated more easily. More particularly, when making a parallel signal transmission of multiple bits such as 32 bits or 64 bits, there exists a case where the logic amplitude changes from a “0” state to a “1” state in all of the bits with the exception of one bit, and in such a case, the effects of the lines on which the logic amplitude of the bits which changed to the “1” state appear at the far-end of the signal line on which the logic amplitude of the bit remained at the “0” state. In some cases, such effects appearing at the far-end become large and no longer negligible. In order to simultaneously achieve the increased operation speed and reduced size and weight of the equipment, it is an object to overcome this crosstalk noise from the point of view of electronic packaging.
But conventionally, in order to reduce the crosstalk noise described above, it was either necessary to increase the physical distance among the signals or to reduce the number of signals which make the transition simultaneously. For this reason, it was either necessary to sacrifice the packaging or mounting density or to sacrifice the performance by relaxing the signal timings.
SUMMARY OF THE INVENTION
Accordingly, it is a general object of the present invention to provide a novel and useful noise elimination method and transmission circuit, in which the problems described above are eliminated.
Another and more specific object of the present invention is to provide a noise elimination method and a transmission circuit which can eliminate a far-end crosstalk of a bus transmission when transmitting signals in the same direction, by a simple means.
Still another object of the present invention is to provide a noise elimination method characterized in that when transmitting signals in the same direction on at least two distributed constant lines, a resistance of a terminating resistor at a far-end is set so that voltages propagated to the far-end become equal between two kinds of propagation modes on coupled distributed constant lines, where the two kinds of propagation modes are a common mode which propagates with respect to a ground plane and a differential mode which propagates between the coupled lines. According to the present invention, it is possible to effectively eliminate the forward far-end crosstalk noise by use of a simple construction.
A further object of the present invention is to provide a noise elimination method characterized in that when first and second driving sources are coupled to respective ends of at least two distributed constant lines on which signals can be transmitted two ways, and a signal is to be transmitted from the first driving source to the other end or from the second driving source to the other end, a resistance of a terminating resistor is set so that an approximately reciprocal relationship exists between an internal resistance of the first or second driving source normalized by a characteristic impedance of the line, and a terminating resistance at a far-end with respect to the first or second driving source normalized by the characteristic impedance of the line. According to the present invention, it is possible to effectively eliminate the forward far-end crosstalk noise by use of a simple construction.
Another object of the present invention is to provide a transmission circuit having at least two distributed constant lines for transmitting signals in the same direction, characterized in that a terminating resistor is coupled at a far-end of the distributed constant lines, and the terminating resistor has a terminating resistance which is set so that an approximately reciprocal relationship exists between the terminating resistance which is normalized by a characteristic impedance of the line and an internal resistance of a driving source which is normalized by the characteristic impedance of the line. According to the present invention, it is possible to effectively eliminate the forward far-end crosstalk noise by use of a simple construction.
Still another object of the present invention is to provide a transmission circuit having at least two distributed constant lines for transmitting signals two ways, and driving sources of the signals on both end of the lines, characterized in that a terminating resistor is coupled to a far-end of the distributed constant lines with respect to each driving source, and the terminating resistor has a terminating resistance which is set so that an approximately reciprocal relationship exists between the terminating resistance which is normalized by a characteristic impedance of the line and an internal resistance of the driving source which is normalized by the characteristic impedance of the line. According to the present invention, it is possible to effectively eliminate the forward far-end crosstalk noise by use of a simple construction.
A further object of the present invention is to provide a transmission circuit coupled to at least two distributed constant lines for transmitting signals in the same direction, characterized by a terminating resistor coupled to a far-end of the distributed constant lines to reduce a far-end crosstalk noise. According to the present invention, it is possible to effectively eliminate the forward far-end crosstalk noise by use of a simple construction.
Another object of the present invention is to provide a transmission circuit coupled to at least two distributed constant lines for transmitting signals in the same direction, characterized by a terminating resistor having a resistance which makes voltages propagated on the distributed constant lines equal between a common mode and a differential mode. According to the present invention, it is possible to effectively eliminate the forward far-end crosstalk noise by use of a simple construction.
Other objects and further features of the present invention will be apparent from the following detailed description when read in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1A and 1B respectively are diagrams for explaining a backward near-end crosstalk for explaining a background of the present invention;
FIG. 2 is a diagram showing the magnitude of a backward near-end crosstalk generated in the transmission circuit shown in FIGS. 1 A and 1 B:
FIG. 3 is a diagram showing a coupling distributed constant line for explaining the operating principle of the present invention;
FIG. 4 is a diagram showing signal changes caused by a terminating resistor at a far-end in a common mode and a differential mode;
FIGS. 5A and 5B respectively are diagrams for explaining elimination of a forward far-end crosstalk noise in a first embodiment of the present invention;
FIG. 6 is a diagram for explaining the elimination of the forward far-end crosstalk noise in a second embodiment of the present invention;
FIGS. 7A through 7E respectively are diagrams showing embodiments of the terminating resistor;
FIGS. 8A and 8B respectively are diagrams showing embodiments of the terminating resistor;
FIG. 9 is a diagram showing an analyzed result of the forward far-end crosstalk;
FIG. 10 is a diagram showing an analyzed result of the forward far-end crosstalk;
FIG. 11 is a diagram showing an analyzed result of the forward far-end crosstalk;
FIG. 12 is a diagram showing an analyzed result of the forward far-end crosstalk;
FIG. 13 is a diagram showing an analyzed result of the forward far-end crosstalk;
FIG. 14 is a diagram showing timings of the forward far-end crosstalk;
FIG. 15 is a diagram a change in the absolute value of the forward far-end crosstalk with respect to a drivability of a driver;
FIG. 16 is a diagram a change in the absolute value of the forward far-end crosstalk with respect to a drivability of a driver;
FIG. 17 is a diagram a change in the absolute value of the forward far-end crosstalk with respect to a drivability of a driver;
FIGS. 18A and 18B respectively are diagrams for explaining a simulation of the forward far-end crosstalk which is generated;
FIGS. 19A and 19B respectively are diagrams for explaining a simulation of the forward far-end crosstalk which is generated;
FIG. 20 is a diagram showing the relationship of the magnitude of a resistance R when a terminating resistor is changed with respect to an optimum value and a forward far-end crosstalk reduction;
FIG. 21 is a diagram showing the relationship of the magnitude of the resistance R when the terminating resistor is changed with respect to the optimum value and the forward far-end crosstalk reduction;
FIG. 22 is a diagram showing the relationship of the magnitude of the resistance R when the terminating resistor is changed with respect to the optimum value and the forward far-end crosstalk reduction; and
FIG. 23 is a perspective view showing a transmission circuit provided on an IC chip.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
First, a description will be given of the operating principle of the present invention.
It is both extremely difficult and complicated to solve the crosstalk noise by mathematical formulas. However, the present inventor positively used mathematical formulas and found that the crosstalk noise generated at a far-end can be made zero theoretically, by selecting a terminating resistance at the far-end to an optimum value.
Two coupling distributed constant lines shown in FIG. 3 are considered, and signal propagations on lines 1 and 2 are solved by Laplace transform based on basic formulas of transmission. Inductances and capacitances of the lines 1 and 2 are taken into consideration as parameters between the lines 1 and 2 . The inductances and the capacitances of the lines 1 and 2 themselves will be referred to as self inductances and self capacitances, and are respectively denoted by L 11 and C 11 with respect to the line 1 and by L 22 and C 22 with respect to the line 2 . In addition, the inductance and the capacitance between the lines 1 and 2 will be referred to as a mutual inductance and a mutual capacitance, and are respectively denoted by L 12 and C 12 .
In this case, the basic formulas of the transmission can be described by the following formulas (1) by taking L and C as matrixes, where v 1 denotes a voltage propagating on the line 1 , and v 2 denotes a voltage propagating on the line 2 . - ∂ ∂ x ( v 1 v 2 ) = ∂ ∂ t ( L 11 L 12 L 21 L 22 ) ( i 1 i 2 ) - ∂ ∂ x ( i 1 i 2 ) = ∂ ∂ t ( C 11 C 12 C 21 C 22 ) ( v 1 v 2 ) ( 1 )
The following formula (2) is obtained by subjecting the above formulas (1) to a Laplace transform so as to describe the formula (2) solely in terms of V. 2 x 2 ( V 1 V 2 ) - s 2 ( L 11 L 12 L 21 L 22 ) ( C 11 C 12 C 21 C 22 ) ( V 1 V 2 ) = 0 ( 2 )
In order to simplify matters, it will be assumed for the sake of convenience that the lines 1 and 2 shown in FIG. 3 have the same characteristic, and that the following relationships stand.
L
11
=L
22
=L
L
12
=L
21
=L
m
C
11
=C
22
=C
C
12
=C
21
=C
m
In this case, a coefficient matrix of the second term in the formula (2) can be described by the following formula (3). ( L 11 L 12 L 21 L 22 ) ( C 11 C 12 C 21 C 22 ) = ( L L m L m L ) ( C C m C m C ) = ( LC + L m C m LC m + L m C LC m + L m C LC + L m C m ) = 1 u 2 ( 1 ξ ξ 1 ) ( 3 )
Here, the following formula (4) stands. ξ = ( L m L + C m C ) / ( 1 + L m C m LC ) u 2 = 1 LC + L m C m ( 4 )
The following formula (5) is obtained by eliminating V 2 . V 1 4 x 4 - 2 ( s u ) 2 V 1 2 x 2 + ( s u ) 4 ( 1 - ξ 2 ) V 1 = 0 ( 5 )
The following formula (6) can be obtained by describing the coefficient as a function of D. φ ( D ) = D 4 - 2 ( s u ) 2 D 2 + ( s u ) 4 ( 1 - ξ 2 ) ( 6 )
The root of φ=(D) can be described by the following formula (7). D = ± s u 1 ± ξ (composite arbitrary)(7)
When the following formula (8) is substituted into the formula (7), the following formula ( 9 ) can be obtained, where the suffixes “C” and “D” respectively indicate a common (or also called even) mode and a differential (or also called odd) mode, u C and u D denote propagation velocities in the respective modes. u C = 1 / ( L + L m ) ( C + C m ) , u D = 1 / ( L - L m ) ( C - C m ) ( 8 ) D = ± s u C , ± s u D ( 9 )
Impedances Z C and Z D also exist in the common mode and the differential mode, respectively, with respect to the specific impedance as indicated by the following formulas (10). Z C = L + L m C + C m , Z D = L - L m C - C m ( 10 )
When the currents and voltages are obtained, the following formulas (11) are obtained. V 1 ( s ) = A 1 ( s ) - x u C s + A 2 ( s ) x u C s + A 3 ( s ) - x u D s + A 4 ( s ) x u D s ( 11 ) V 2 ( s ) = A 1 ( s ) - x u C s + A 2 ( s ) x u C s - A 3 ( s ) - x u D s - A 4 ( s ) x u D s I 1 ( s ) = A 1 ( s ) Z C - x u C s - A 2 ( s ) Z C x u C s + A 3 ( s ) Z D - x u D s - A 4 ( s ) Z D x u D s I 2 ( s ) = A 1 ( s ) Z C - x u C s - A 2 ( s ) Z C x u C s - A 3 ( s ) Z D - x u D s + A 4 ( s ) Z D x u D s
Under a boundary condition x=0, the following relationships exist.
V
1
=V
0
−R
1
I
1
, V
2
=−R
N
I
2
On the other hand, the following relationships exist under a boundary condition x=1.
V 1 =R 2 I 1 , V 2 =R F I 2
The following formulas (12) are simultaneous equations for A 1 through A 4 , and V 1 and V 2 can be obtained by solving the simultaneous equations and substituting the solutions into the original formulas (11). When the obtained V 1 and V 2 are subjected to a Laplace inverse transform, temporal functions v 1 (t) and v 2 (t) are obtained. These results are also a combination of a linear operator and a time lag, and can be obtained by simple calculations similarly as described above. A 1 + A 2 + A 3 + A 4 = V 0 - R 1 ( A 1 Z C - A 2 Z C + A 3 Z D - A 4 Z D ) ( 12 ) A 1 + A 2 - A 3 - A 4 = - R N ( A 1 Z C - A 2 Z C - A 3 Z D + A 4 Z D ) A 1 - τ C s + A 2 τ C s + A 3 - τ D s + A 4 τ D s = R 2 ( A 1 Z C - τ C s - A 2 Z C τ C s + A 3 Z D - τ D s - A 4 Z D τ D s ) A 1 - τ C s + A 2 τ C s - A 3 - τ D s - A 4 τ D s = R F ( A 1 Z C - τ C s - A 2 Z C τ C s - A 3 Z D - τ D s + A 4 Z D τ D s ) ( 1 + R 1 Z C ) A 1 + ( 1 - R 1 Z C ) A 2 + ( 1 + R 1 Z D ) A 3 + ( 1 - R 1 Z D ) A 4 = V 0 ( 1 + R N Z C ) A 1 + ( 1 - R N Z C ) A 2 - ( 1 + R N Z D ) A 3 - ( 1 - R N Z D ) A 4 = 0 ( 1 - R 2 Z C ) - τ C s A 1 + ( 1 + R 2 Z C ) τ C s A 2 + ( 1 - R 2 Z D ) - τ D s A 3 + ( 1 + R 2 Z D ) τ D s A 4 = 0 ( 1 - R F Z C ) - τ C s A 1 + ( 1 + R F Z C ) τ C s A 2 - ( 1 - R F Z D ) - τ D s A 3 - ( 1 + R F Z D ) τ D s A 4 = 0
When these results are considered as a function of x, e −(x/u C )s , for example, means carrying out an operation f(t−x/u C ) with respect to the temporal function f(t). Since x/u C describes the time it takes to travel the distance x at the velocity u C , it is a waveform propagating in the x direction. Similarly, it may be seen that a waveform propagating in a direction opposite to the x direction is a composed of signals propagating at the velocities u C and u D .
Hence, the following formula (13) can be obtained, and the following formula (14) can be obtained by denoting the coefficient matrix equation by Δ. ( ( 1 + R 1 Z C ) ( 1 - R 1 Z C ) ( 1 + R 1 Z D ) ( 1 - R 1 Z D ) ( 1 + R N Z C ) ( 1 - R N Z C ) - ( 1 + R N Z D ) - ( 1 - R N Z D ) ( 1 - R 2 Z C ) - τ C s ( 1 + R 2 Z C ) τ C s ( 1 - R 2 Z D ) - τ D s ( 1 + R 2 Z D ) τ D s ( 1 - R F Z C ) - τ C s ( 1 + R F Z C ) τ C s - ( 1 - R F Z D ) - τ D s - ( 1 + R F Z D ) τ D s ) ( A 1 A 2 A 3 A 4 ) = ( V 0 0 0 0 ) ( 13 ) Δ = ( 1 + R 1 Z C ) ( 1 - R 1 Z C ) ( 1 + R 1 Z D ) ( 1 - R 1 Z D ) ( 1 + R N Z C ) ( 1 - R N Z C ) - ( 1 + R N Z D ) - ( 1 - R N Z D ) ( 1 - R 2 Z C ) - τ C s ( 1 + R 2 Z C ) τ C s ( 1 - R 2 Z D ) - τ D s ( 1 + R 2 Z D ) τ D s ( 1 - R F Z C ) - τ C s ( 1 + R F Z C ) τ C s - ( 1 - R F Z D ) - τ D s - ( 1 + R F Z D ) τ D s = [ - { 2 ( 1 + R 1 R N Z C Z D ) + ( R 1 + R N ) ( 1 Z C + 1 Z D ) } × { 2 ( 1 + R 2 R F Z C Z D ) + ( R 2 + R F ) ( 1 Z C + 1 Z D ) } + { 2 ( 1 - R 1 R N Z C Z D ) + ( R 1 + R N ) ( 1 Z C - 1 Z D ) } × { 2 ( 1 - R 2 R F Z C Z D ) + ( R 2 + R F ) ( 1 Z C - 1 Z D ) } - 2 τ D s + 8 ( R 1 - R N ) ( R 2 - R F ) Z C Z D - ( τ C + τ D ) s + { 2 ( 1 - R 1 R N Z C Z D ) - ( R 1 + R N ) ( 1 Z C - 1 Z D ) } × { 2 ( 1 - R 2 R F Z C Z D ) - ( R 2 + R F ) ( 1 Z C - 1 Z D ) } - 2 τ C s - { 2 ( 1 + R 1 R N Z C Z D ) - ( R 1 + R N ) ( 1 Z C + 1 Z D ) } × { 2 ( 1 + R 2 R F Z C Z D ) - ( R 2 + R F ) ( 1 Z C + 1 Z D ) } - ( 2 τ C + 2 τ D ) s ] ( τ C + τ D ) s ( 14 )
Based on the above, the unknowns A 1 , A 2 , A 3 and A 4 can be obtained by the following formulas (15). A 1 = V 0 Δ [ - ( 1 + R N Z D ) { 2 ( 1 + R 2 R F Z C Z D ) + ( R 2 + R F ) ( 1 Z C + 1 Z D ) } + ( 1 - R N Z D ) { 2 ( 1 - R 2 R F Z C Z D ) + ( R 2 + R F ) ( 1 Z C - 1 Z D ) } - 2 τ p s + 2 ( 1 - R N Z C ) R 2 - R F Z D - ( τ C + τ D ) s ] ( τ C + τ D ) s ( 15 ) A 2 = V 0 Δ [ - 2 ( 1 + R N Z C ) R 2 - R F Z D - ( τ C + τ D ) s + ( 1 + R N Z D ) { 2 ( 1 - R 2 R F Z C Z D ) - ( R 2 + R F ) ( 1 Z C - 1 Z D ) } - 2 τ C s - ( 1 - R N Z D ) { 2 ( 1 + R 2 R F Z C Z D ) - ( R 2 + R F ) ( 1 Z C + 1 Z D ) } - ( 2 τ C + 2 τ D ) s ] ( τ C + τ D ) s A 3 = V 0 Δ [ - ( 1 + R N Z C ) { 2 ( 1 + R 2 R F Z C Z D ) + ( R 2 + R F ) ( 1 Z C + 1 Z D ) } + 2 ( 1 - R N Z D ) R 2 - R F Z C - ( τ C + τ D ) s + ( 1 - R N Z C ) { 2 ( 1 - R 2 R F Z C Z D ) - ( R 2 + R F ) ( 1 Z C - 1 Z D ) } - 2 τ C s ] ( τ C + τ D ) s A 4 = V 0 Δ [ ( 1 + R N Z C ) { 2 ( 1 - R 2 R F Z C Z D ) + ( R 2 + R F ) ( 1 Z C - 1 Z D ) } - 2 τ D s - 2 ( 1 + R N Z D ) R 2 - R F Z C - ( τ C + τ D s ) - ( 1 - R N Z C ) { 2 ( 1 + R 2 R F Z C Z D ) - ( R 2 + R F ) ( 1 Z C + 1 Z D ) - ( 2 τ C + 2 τ D ) s ] ( τ C + τ D ) s
When obtaining the forward far-end crosstalk, the resistances of the resistors shown in FIG. 3 are set to R 1 =r, R 2 =R, R N =r and R F =R in the following formulas (16) and (17) for the sake of convenience to simplify matters. In addition, a common one-way time τ C and a differential one-way time τ D are both denoted by τ, that is, it is assumed that τ C =τ D =τ. Δ = - { 2 ( 1 + R 1 R N Z C Z D ) + ( R 1 + R N ) ( 1 Z C + 1 Z D ) } × { 2 ( 1 + R 2 R F Z C Z D ) + ( R 2 + R F ) ( 1 Z C + 1 Z D ) } = - 4 { ( 1 + r 2 Z C Z D ) + r ( 1 Z C + 1 Z D ) } { ( 1 + R 2 Z C Z D ) + R ( 1 Z C + 1 Z D ) } = - 4 ( 1 + r Z C ) ( 1 + r Z D ) ( 1 + R Z C ) ( 1 + R Z D ) ( 16 ) A 1 - τ s = V 0 Δ [ - ( 1 + R N Z D ) { 2 ( 1 + R 2 R F Z C Z D ) + ( R 2 + R F ) ( 1 Z C + 1 Z D ) } ] - τ s = - 2 V 0 Δ ( 1 + r Z D ) { ( 1 + R 2 Z C Z D ) + R ( 1 Z C + 1 Z D ) } - τ s A 2 τ s = V 0 Δ [ - 2 ( 1 + R N Z C ) R 2 - R F Z D + ( 1 + R N Z D ) { 2 ( 1 - R 2 R F Z C Z D ) - ( R 2 + R F ) ( 1 Z C - 1 Z D ) } ] e - τ s = 2 V 0 Δ ( 1 + r Z D ) { ( 1 - R 2 Z C Z D ) - R ( 1 Z C - 1 Z D ) } - τ s ( V 2 C ) x = 1 , t = τ = A 1 - τ s + A 2 τ s = - 4 RV 0 Δ ( 1 + r Z D ) ( R Z C Z D + 1 Z C ) - τ s ( 17 ) A 3 - τ s = V 0 Δ [ - ( 1 + R N Z C ) { 2 ( 1 + R 2 R F Z C Z D ) + ( R 2 + R F ) ( 1 Z C + 1 Z D ) } ] - τ s = - 2 V 0 Δ ( 1 + r Z C ) { ( 1 + R 2 Z C Z D ) + R ( 1 Z C + 1 Z D ) } - τ s A 4 τ s = V 0 Δ ( 1 + R N Z C ) { 2 ( 1 - R 2 R F Z C Z D ) + ( R 2 + R F ) ( 1 Z C - 1 Z D ) } - τ s = 2 V 0 Δ ( 1 + r Z C ) { ( 1 - R 2 Z C Z D ) + R ( 1 Z C - 1 Z D ) } - τ s ( V 2 D ) x = 1 , t = τ = - A 3 - τ s - A 4 τ s = 4 RV 0 Δ ( 1 + r Z C ) ( R Z C Z D + 1 Z D ) - τ s ( ( ( V 2 ) x = 1 , t = τ = V 2 C ) x = 1 , t = τ + V 2 D ) x = 1 , t = τ = 4 RV 0 Δ { ( 1 - R r Z C Z D ) ( 1 Z D - 1 Z C ) - τ s = R ( 1 Z D - 1 Z C ) ( Rr Z C Z D - 1 ) ( 1 + r Z C ) ( 1 + r Z D ) ( 1 + R Z C ) ( 1 + R Z D ) - τ s V 0
Accordingly, it can be seen that the forward far-end crosstalk becomes zero when (Rr)/(Z C Z D )=1. But since each of Z C and Z D is equal to a square of the characteristic impedance Z 0 of the other when one of the coupling distributed constant lines 1 and 2 is terminated by a matched termination, the following relationship stands.
R/Z
0
=Z
0
/r
In other words, when normalized by the characteristic impedance of the line, a reciprocal relationship exists between the resistance at the near-end and the terminating resistance at the far-end.
FIG. 4 is a diagram showing signal changes caused by the terminating resistor at the far-end in the common mode and the differential mode. In FIG. 4, the ordinate indicates the voltage in arbitrary units, and the abscissa indicates the resistance R in Ω. In addition, V 2C indicates a voltage propagating on the line 2 in the common mode, V 2D indicates the voltage propagating on the line 2 in the differential mode, V 2 indicates a forward far-end crosstalk noise, that is, the crosstalk noise generated in the line 2 . As may be seen from FIG. 4, the voltage V 2C in the common mode and the voltage V 2D in the differential mode change depending on the resistance R of the terminating resistor at the far-end, and a point exists where V 2C =V 2D . Since r=30Ω, Z C =102Ω, Z D =47Ω in FIG. 4, V 2C =V 2D at the point where R=160Ω.
Therefore, by setting the resistance R of the terminating resistor to R=Z 0 2 /r, the forward far-end crosstalk value theoretically becomes zero. Of course, it is not essential from the practical point of view that the crosstalk value is exactly equal to zero. As will be described later, the inventor has found that sufficient effects are obtainable when the resistance R of the terminating resistor increases or decreases by approximately 50 to 30% with respect to the maximum value of Z 0 2 /r.
FIGS. 5A and 5B respectively are diagrams for explaining the elimination of the forward far-end crosstalk noise in a first embodiment of the present invention. FIG. 5A shows a driving line 10 , a driver (driving source) 11 , a receiver 12 , a passive line 20 , a driver (driving source) 21 , and a receiver 22 . FIG. 5B additionally shows an internal resistance 13 of the driver 11 , a terminating resistor 14 , an internal resistance 23 of the driver 21 , and a terminating resistor 24 .
When signals are transmitted in the same direction on the two lines 10 and 20 which are close to each other as shown in FIG. 5A, the forward far-end crosstalk refers to the noise which is generated by the signal on the driving line 10 on the side of the receiver 22 on the other passive line 20 .
When the value of the internal resistance 13 of the driver 11 which is the driving source is denoted by r, the characteristic impedance of the driving line 10 and the passive line 20 is denoted by Z 0 , and the value of the terminating resistor 24 connected at the far-end of the passive line 20 is denoted by R, the value R is set so as to satisfy R=Z 0 2 /r. In this case, it is possible to make the forward far-end crosstalk value theoretically zero.
FIG. 6 is a diagram for explaining the elimination of the forward far-end crosstalk noise in a second embodiment of the present invention. In FIG. 6, signal transmissions on distributed constant lines 30 and 40 can be made from both the left to right and from the right to left. In FIG. 6, the reference numerals 31 , 34 , 41 and 44 indicate drivers (driving sources), the reference numerals 33 , 36 , 43 and 46 indicate receivers, the reference numerals 32 , 35 , 42 and 45 indicate internal resistances of the drivers 31 , 34 , 41 and 44 , and the reference numerals 37 , 38 , 47 and 48 indicate terminal resistors.
In this second embodiment, the first embodiment described above is expanded to the two-way transmission. A case will now be considered where the signal is transmitted from the left to right in FIG. 6 . In this case, the drivers 34 and 44 are set to a high impedance state. When the signal line 30 is regarded as a driving line and the signal line 40 is regarded as a passive line, the circuit construction becomes similar to that shown in FIG. 5 B. Accordingly, when the characteristic impedance of the signal lines 30 and 40 is denoted by Z 0 , the far-end crosstalk noise can be eliminated by setting a value R 1 of the terminal resistor 37 so as to satisfy R 1 =Z 0 2 /r 1 , where r 1 denotes the value of the internal resistance 32 of the driver 31 .
On the other hand, when the signal line 40 is regarded as a driving line and the signal line 30 is regarded as a passive line, the far-end crosstalk noise on the signal line 30 due to the signal line 40 can be eliminated by setting a value R 2 of the terminal resistor 47 so as to satisfy R 2 =Z 0 2 /r 2 , where r 2 denotes the value of the internal resistance 42 of the driver 41 . In addition, in order to eliminate the far-end crosstalk noise when making a signal transmission in a reverse direction, from the right to left, values R 3 and R 4 of the terminal resistors 38 and 39 which are connected are set so as to respectively satisfy R 3 =Z 0 2 /r 3 and R 4 =Z 0 2 /r 4 , where r 3 and r 4 respectively denote the values of the internal resistances 35 and 45 of the drivers 34 and 44 .
FIGS. 7A through 7E and FIGS. 8A and 8B are diagrams showing embodiments of the terminal resistor.
In FIG. 7A, one end of a terminating resistor 50 which is provided to eliminate the forward far-end crosstalk noise described above is grounded, and a terminating voltage is set to a logic amplitude “0”. In this embodiment, only one terminating resistor 50 is required for each line, and the construction is simple. When this terminating resistor 50 is provided, there is an advantage in that no level change occurs on the “0” side of the original signal.
In FIG. 7B, one end of a terminating resistor 51 which is provided to eliminate the forward far-end crosstalk noise described above is connected to a power supply voltage Vcc, and a terminating voltage is set to a logic amplitude “1”. In this embodiment, only one terminating resistor 51 is required for each line. When this terminating resistor 51 is provided, there is an advantage in that no level change occurs on the “1” side of the original signal.
In FIG. 7C, one end of a terminating resistor 52 which is provided to eliminate the forward far-end crosstalk noise described above is connected to an intermediate voltage V TH between the logic amplitudes “0” and “1”. This intermediate voltage V TH satisfies a relationship 0<V TH <Vcc, where Vcc is the power supply voltage. In this embodiment, only one terminating resistor 52 is required for each line. When this terminating resistor 52 is provided, a slight level change occurs on the “0” side and the “1” side of the original signal, but there is an advantage in that the symmetry of the waveform is maintained when the intermediate voltage V TH is selected exactly to the center between 0 and Vcc.
In FIG. 7D, the terminating resistor which is provided to eliminate the forward far-end crosstalk noise described above is formed by two resistors 53 and 54 . One end of the resistor 53 is connected to the power supply voltage Vcc (that is, to the logic amplitude “1”), and one end of the resistor 54 is grounded (that is, connected to he logic amplitude “0”). A node connecting these resistors 53 and 54 is connected to the far-end of the line. When the resistances of the resistors 53 and 54 are respectively denoted by 2 R, this circuit becomes equivalent to a circuit surrounded by a dotted line and shown on the right side in FIG. 7 D. In the circuit surrounded by the dotted line, a resistor 55 having a resistance R is connected between the far-end and a voltage Vcc/2 which is ½ the power supply voltage Vcc. In this case, there is an advantage in that the circuit construction becomes equivalent to terminating to an intermediate voltage, without the need to prepare a terminating voltage.
In FIG. 7E, the terminating resistor which is provided to eliminate the forward far-end crosstalk noise described above is formed by a non-inverting gate circuit 60 . An input and an output of this non-inverting gate circuit 60 are connected directly or indirectly via a resistor 63 as shown. In addition, the far-end of the line and the input of the non-inverting gate circuit 60 are connected via a resistor 62 . When the resistance of the resistor 62 is denoted by R 11 , the resistance of the resistor 63 is denoted by R 12 , and the output resistance of the non-inverting gate circuit 60 is denoted by r 11 , the resistance R of the terminating resistor as a whole can be described by R=R 11 +r 11 +R 12 .
When the line is simply terminated as in the above described embodiments shown in FIGS. 7A through 7D, the power consumption increases. However, by employing the construction of the embodiment shown in FIG. 7E, it is possible to eliminate the power consumption caused by the terminating resistor in the steady state. Furthermore, by selecting the output resistance r 11 of the non-inverting gate circuit 60 equal to the resistance R of the terminating resistor, it is possible to obtain an effect whereby the connections of the resistors 62 and 63 shown in FIG. 7E may be omitted. In addition, by employing the construction in which the input of the non-inverting gate circuit 60 is not directly connected to the line but is connected to the line through the resistor 62 , the construction becomes strong against electrostatic discharge failure, and the waveform will not be distorted by the electrostatic capacitance of the non-inverting gate circuit 60 .
In FIG. 8A, the resistance of a terminating resistor 70 which is provided to eliminate the forward far-end crosstalk noise described above is selectable by an external control input 71 . When forming the circuit construction shown in FIG. 7E in the form of an integrated circuit, it is necessary to use different parts such that the resistance of the terminating resistor is different depending on the drivability of the driver. But by providing a plurality of kinds of resistances and making one of the resistances selectable depending on the control input 71 , it becomes possible to use only one kind of part and cope with the different drivability of the driver. In addition, even in a case where a resistor (damping resistor) is inserted in series with espect to the driver after the circuit is constructed and the equivalent internal resistance of the driving source changes, it is unnecessary to change the part, and it becomes possible to realize an optimum noise elimination by simply changing the setting by the control input 71 .
FIG. 8B shows an embodiment of the construction for varying the resistance of the terminating resistor 70 shown in FIG. 8A depending on the control input 71 . In FIG. 8B, outputs of tristate gates 72 A through 72 C can be controlled to a high impedance state or an active state, based respectively on control inputs 71 A through 71 C. If it is assumed that drivabilities of 1 mA, 2 mA and 4 mA are respectively obtained when the tristate gates 72 A through 72 C are active, it is possible to obtain resistances depending on the currents of 1 mA to 7 mA, based on a combination of the control inputs 71 A through 71 C. Of course, the circuit construction for making the resistance of the terminating resistor variable is not limited to the circuit construction shown in FIG. 8 B.
FIGS. 9 through 13 are diagrams showing analyzed results of the forward far-end crosstalk.
FIG. 9 shows signal waveforms appearing at the near-end and the far-end of the driving line 10 and the passive line 20 of the transmission circuit shown in FIG. 5B, in a case where the value r of the internal resistance 13 of the driver 11 is 10Ω and the resistance R of the terminating resistor 24 is infinitely large, that is, when the terminating resistor 24 is not connected. The drivability of the driver 11 is approximately 24 mA, and the characteristic impedance Z 0 of the driving line 10 and the passive line 20 is 69Ω.
In FIG. 9, the ordinate indicates the magnitude of the voltage, and the abscissa indicates the time. In FIG. 9, a thin solid line v 1 (near) indicates a voltage change on the driving line 10 on the side of the driver 11 (near-end), a thin dotted line v 1 (far) indicates a voltage change on the driving line 10 on the side of the receiver 12 (far-end), a bold solid line v 2 (near) indicates a voltage change on the passive line 20 on the side of the driver 21 (near-end), and a bold dotted line v 2 (far) indicates a voltage change on the passive line 20 on the side of the receiver 22 (far-end). The same designations are used in FIGS. 10, 11 , 12 and 13 which will be described hereinafter.
As may be seen from the analyzed results shown in FIG. 9, the forward far-end crosstalk does clearly appear when the resistance R of the terminating resistor 24 is infinitely large, although the forward far-end crosstalk is not as large as the backward near-end crosstalk described above in conjunction with FIG. 2 .
In a normal transmission circuit, when connecting the terminating resistor, the resistance of the terminating resistor is in general matched to the characteristic impedance Z 0 so as to eliminate the signal reflection. Hence, when the resistance R of the terminating resistor 24 shown in FIG. 5B is set to R=Z 0 =69Ω, and the signal waveforms appearing at the near-end and the far-end of the driving line 10 and the passive line 20 are analyzed, the analyzed results shown in FIG. 10 are obtained. In this case shown in FIG. 10, the forward far-end crosstalk appears at the far-end of the passive line 20 , as indicated by the bold dotted line v 2 (far).
In the present invention, in the transmission circuit having the same construction as that described above, the resistance R of the terminating resistor 24 is selected to R=Z 0 2 /r. In other words, the resistance R is set as follows.
R=Z 0 2 /r =69 2 /10(Ω)=475(Ω)
In this case, the signal waveforms appearing at the near-end and the far-end of the driving line 10 and the passive line 20 become as shown in FIG. 11 . As may be seen from FIG. 11, virtually no forward far-end crosstalk is generated at the far-end of the passive line 20 . A whisker-like noise is generated theoretically (based on calculations) at the far-end of the passive line 20 , but this noise only has a width of approximately 50 ps, and such a noise signal of 100 ps or less can completely be neglected since such a small noise signal will actually disappear due to rounding of the waveform.
FIG. 12 shows signal waveforms similar to those shown in FIG. 8, with respect to a case where the value r of the internal resistance 13 of the driver 11 is 20Ω in the transmission circuit shown in FIG. 5 B. The resistance R of the terminating resistor 24 is set as follows.
R=Z 0 2 /r =69 2 /20(Ω)=237(Ω)
In this case, the forward far-end crosstalk also becomes zero.
FIG. 13 shows signal waveforms similar to those shown in FIG. 11, with respect to a case where the value r of the internal resistance 13 of the driver 11 is 30Ω in the transmission circuit shown in FIG. 5 B. The resistance R of the terminating resistor 24 is set as follows.
R=Z 0 2 /r =69 2 /30(Ω)=158(Ω)
In this case, the forward far-end crosstalk also becomes zero.
Next, a description will be given of how the absolute value of the forward far-end crosstalk changes with respect to the drivability of the driver 11 , by referring to FIGS. 14 through 17.
For the sake of convenience, timings of the forward far-end crosstalk are named 1T, 3T and 5T as shown in FIG. 14. 1T indicates a noise value after the time required to travel the line one way, 3T indicates a noise value after the time required to travel the line one way and after the time required to travel the line on both the going and returning ways also elapses, and 5T indicates a noise value after the time required to travel the line on both the going and returning ways elapses after the timing of 3T.
In FIGS. 15 through 17, the abscissa indicates the drivability of the driver in mA, and the ordinate indicates the magnitude of the crosstalk when the magnitude is normalized by 1. The drivability of the driver can be described by the following.
Drivability (mA)=400(mV)/(1.5 ×r (Ω))
FIG. 15 shows a case where the resistance R of the terminating resistor is 475Ω and corresponds to the case shown in FIG. 11 . FIG. 16 shows a case where the resistance R of the terminating resistor is 237Ω and corresponds to the case shown in FIG. 12 . FIG. 17 shows a case where the resistance R of the terminating resistor is 158Ω and corresponds to the case shown in FIG. 13 . The crosstalk value at the timings 1T, 3T and 5T changes depending on the drivability of the driver, as shown in FIGS. 15 through 17.
FIGS. 18A and 18B and FIGS. 19A and 19B respectively are diagrams for explaining simulations of the forward far-end crosstalk which is generated, by use of a software circuit simulator. The simulation results shown in FIGS. 18A and 19A respectively correspond to the analyzed result shown in FIG. 12 described above.
FIG. 18A shows the simulation result which is obtained with respect to two distributed constant lines formed by the driving line 10 and the passive line 20 shown in FIG. 18B. A pattern length of the line was set to 14 cm. The characteristic impedance Z 0 of the line was set to 73Ω, and the internal resistance r of the driving source was set to 20Ω.
In FIG. 18A, v 10 indicates an output signal of the driving source on the driving line 10 , v 11 indicates a signal observed at an observation point P 1 on the driving line 10 when the resistance R of the terminating resistor is set infinitely large, and v 12 indicates a signal change observed at the observation point P 1 on the driving line 10 when the resistance R of the terminating resistor is set to 279Ω a value close to (Z 0 2 /r).
In addition, v 21 indicates a signal observed at an observation point P 2 on the passive line 20 when the resistance R of the terminating resistor is set infinitely large, and v 22 indicates a signal change obverted at the observation point P 2 on the passive line 20 when the resistance R of the terminating resistor is set to 279Ω a value close to (Z 0 2 /r).
As may be seen from FIG. 18A, virtually no crosstalk noise appears at the far-end of the passive line 20 if the resistance R of the terminating resistor is set to a value close to (Z 0 2 /r).
FIG. 19A shows the simulation result which is obtained with respect to the transmission circuit shown in FIG. 19 B. In FIG. 19B, 5 driving lines 10 are arranged on both sides of the passive line 20 , that is, a total of 10 driving lines 10 are provided. Otherwise, the conditions of this simulation are the same as those used in FIGS. 18A and 18B. Of course, a crosstalk value at an observation point P 4 on the passive line 20 shown in FIG. 19B becomes larger than the crosstalk value observed in FIG. 18 B. However, when the signal v 22 which is obtained when the resistance R of the terminating resistor is set to 279Ω is compared with the signal v 21 which is obtained when the resistance R of the terminating resistor is set infinitely large, that is, R=∞, the crosstalk value is negligibly small. In the signal v 22 , a slight fluctuation in the negative direction appears in correspondence with the rise of the signal v 12 , but this slight fluctuation only occurs for an extremely short time, and no problems are introduced thereby from the practical point of view.
Therefore, by setting the resistance R of the terminating resistor to R=(Z 0 2 /r), it is possible to make the forward far-end crosstalk noise zero. However, when applying the present invention, it is not essential from the practical point of view that the resistance R is set exactly to the above value. For this reason, a description will now be given of the relationship of the error in the terminating resistor and the change in the crosstalk reducing effect.
FIGS. 20 through 22 are diagrams showing the relationship of the resistance R and the forward far-end crosstalk reduction with respect to a case where the terminating resistor is changed from the optimum value R=(Z 0 2 /r). FIG. 20 shows a case where the internal resistance r of the driver is 10Ω, FIG. 21 shows a case where the internal resistance r of the driver is 20Ω, and FIG. 22 shows a case where the internal resistance r of the driver is 30Ω.
In FIGS. 20 through 22, the abscissa indicates the magnitude of the resistance R of the terminating resistor normalized by the optimum value (Z 0 2 /r), and the ordinate indicates the crosstalk value which is normalized by the crosstalk value which is obtained when the resistance R is infinitely large, that is, R=∞. For example, 0.2 on the scale of the ordinate indicates that the crosstalk noise value can be reduced by up to 20%, that is, reduced to a maximum of ⅕, as compared to the case where no measures are taken to reduce the crosstalk noise. In FIGS. 20 through 22, 1T, 3T and 5T indicate the noise values at the timings described above in conjunction with FIG. 14 .
If the crosstalk value can be reduced by up to 20%, this noise elimination measure is sufficient from the practical point of view. Hence, when this is used as a judging value, tolerable values are in the range of 0.7 times to 1.5 times with respect to the maximum value of R=(Z 0 2 /r).
Accordingly, it may be regarded that the arrangement falls within the technical range of the present invention if the resistance R of the terminating resistor connected at the far-end of the passive line falls at least within the following range. The resistance R of the terminating resistor which is matched to the characteristic impedance of the line is considerably smaller than a value within this range.
( Z 0 2 /r )×0.7 ≦R ≦( Z 0 2 /r )×1.5
Furthermore, if the resistance R of the terminating resistor connected at the far-end of the passive line falls within the following range, the crosstalk value becomes less than or equal to 10% of the crosstalk value which is obtained when no terminating resistor is connected.
FIG. 23 is a perspective view showing a transmission circuit provided in an IC chip. In FIG. 23, a transmission circuit 100 according to the present invention is provided within an IC chip 101 . In addition, the IC chip 101 is provided on a board 102 , that is, a circuit board provided within a communication unit or an information processing apparatus such as a personal computer. Of course, IC chips and elements other than the IC chip 101 may also be provided on the board 102 , but such other IC chips and elements are not directly related to the subject matter of the present invention, and an illustration thereof will be omitted. In addition, the board 102 may of course be constructed to be arranged externally to the apparatus.
Therefore, according to the present invention, it is possible to effectively eliminate the forward far-end crosstalk noise by use of a simple construction. This effect of eliminating the forward far-end crosstalk noise cannot be achieved by other methods such as increasing the pattern gap or reducing the line impedance. According to such other methods, it may be possible to slightly reduce the crosstalk noise, however, it is not only difficult to reduce the crosstalk to a value close to zero, but from the practical point of view, other problems are newly introduced.
Further, the present invention is not limited to these embodiments, but various variations and modifications may be made without departing from the scope of the present invention.
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A noise elimination method is characterized in that when transmitting signals in the same direction on at least two distributed constant lines, a resistance of a terminating resistor at a far-end is set so that voltages propagated to the far-end become equal between two kinds of propagation modes on coupled distributed constant lines. The two kinds of propagation modes are a common mode which propagates with respect to a ground plane and a differential mode which propagates between the coupled lines.
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BACKGROUND OF THE INVENTION
The present invention relates to a radiographic image reading method employing a radiographic image conversion panel such as an accumulative phosphor (stimulating phosphor plate) and to a radiographic image reading apparatus.
When radioactive rays (X-rays, α-rays, beta rays, gamma rays and ultraviolet rays) are applied to a phosphor of a certain type, a part of the radiation energy is accumulated in the phosphor. It has been known that when an excitation light such as a visible light is applied to a phosphor, the phosphor emits light through stimulation in accordance with energy accumulated in the phosphor. A phosphor indicating this property is called an accumulative phosphor or a stimulative phosphor.
By utilizing this stimulative phosphor, it is possible to record temporarily radiographic image information of the human body on an accumulative phosphor (a radiographic image conversion panel) provided on a sheet, then to scan the radiographic image conversion panel with an excitation light such as a laser beam so that a stimulated emission light may be generated, and to read photoelectrically the stimulated emission light thus generated to obtain image signals.
Incidentally, the radiographic image conversion panel is not controlled strictly in terms of its sensitivity. Namely, even in the case of radiographic image conversion panels under the same brand, they delicately differ in terms of sensitivity, depending on the date of production.
In the case of an apparatus wherein a radiographic image conversion panel is housed in a cassette for radiographing and reading, in particular, it can happen that new and old radiographic image conversion panels each having different sensitivity are housed in the same cassette.
In this case, a signal value of the radiographic image is used by a radiographer to judge whether a level of the dose of irradiation is high or low. Therefore, when the signal value varies depending on the radiographic image conversion panel, it is impossible to judge or control the level of the dose of irradiation.
Further, when radiographing for plural radiographic images under the condition that radiographic image conversion panels each having different sensitivity are present as a mixture, radiographic images each having a different signal value are obtained, although the same subject is radiographed under the same dose of X-rays. Therefore, it is difficult to make a correct diagnosis.
SUMMARY OF THE INVENTION
The invention has been achieved to solve the aforesaid problem, and its object is to realize a radiographic image reading method and a radiographic image reading apparatus which make it possible to obtain the constant signal value for the constant dose of X-rays, independently of sensitivity of the radiographic image-conversion panel.
Methods and structures for solving the aforesaid problems will be explained as follows.
(1) A radiographic image reading method of reading a radiographic image on a radiographic image conversion panel and for obtaining radiographic image information; comprising steps of:
reading panel discriminating information corresponding to the radiographic image conversion panel, thereby obtaining information regarding the radiographic image conversion panel; and
applying image processing for the radiographic image information based on the information regarding the radiographic image conversion panel.
(2) A radiographic image reading apparatus, comprising:
image reading means for reading a radiographic image on a radiographic image conversion panel and for obtaining radiographic image information;
panel discriminating information reading means for reading panel discriminating information corresponding to the radiographic image conversion panel and for obtaining information regarding the radiographic image conversion panel;
image processing means for applying image processing for the radiographic image information; and
control means for controlling the image processing means so as to apply the image processing for the radiographic image information on the basis of the information regarding the radiographic image conversion panel.
With the invention described in Items (1) and (2), since image processing can be applied to radiographic image information in accordance with a radiographic image conversion panel, the radiographic image information more suitable for diagnosis can be obtained.
Further, since the image processing conformable to the characteristics of the radiographic image conversion panel, such as the sensitivity of the radiographic image conversion panel can be conducted by obtaining information regarding the manufacturing date of the radiographic image conversion panel, the version of the radiographic image conversion panel, fading information or the material constituting the radiographic image conversion panel as the information regarding the radiographic image conversion panel, the radiographic image information more suitable for diagnosis can be obtained.
(3) A radiographic image reading method of reading a radiographic image on a radiographic image conversion panel and for obtaining radiographic image information; comprising steps of:
reading panel discriminating information corresponding to the radiographic image conversion panel, thereby obtaining information regarding the radiographic image conversion panel; and
warning information regarding time limit for use of the radiographic image conversion panel.
(4) A radiographic image reading apparatus, comprising:
image reading means for reading a radiographic image on a radiographic image conversion panel and for obtaining radiographic image information;
discriminating information reading means for reading panel discriminating information corresponding to the radiographic image conversion panel and for obtaining information regarding the radiographic image conversion panel; and
warning means for warning information regarding time limit for use of the radiographic image conversion panel.
With the invention described in Items (3) and (4), the image deterioration caused by the use of the radiographic image conversion panel whose time limit for use is terminated can be refrained, the radiographic image information more suitable for diagnosis can be obtained.
(5) A radiographic image conversion panel for storing a radiographic image, comprising:
a panel discriminating section provided with panel discriminating information regarding the manufacturing date of the radiographic image conversion panel, the version of the radiographic image conversion panel, fading information or the material constituting the radiographic image conversion panel.
(6) A cassette in which a radiographic image conversion panel for storing a radiographic image is accommodated, comprising:
an accommodating section in which the radiographic image conversion panel for storing a radiographic image is accommodated; and
a panel discriminating section provided with panel discriminating information regarding the manufacturing date of the radiographic image conversion panel, the version of the radiographic image conversion panel, fading information or the material constituting the radiographic image conversion panel.
With the invention described in Items (5) and (6), since image processing can be applied in accordance with a radiographic image conversion panel, the radiographic image information more suitable for diagnosis can be obtained.
(7) A radiographic image reading method, comprising, steps of:
reading panel discriminating information corresponding to the radiographic image conversion panel, thereby obtaining information regarding the radiographic image conversion panel;
obtaining a reading condition to read radiographic image information stored in the radiographic image conversion panel on the basis of the information regarding the radiographic image conversion panel; and
reading the radiographic image-information stored in the radiographic image conversion panel on the basis of the reading condition.
(8) A radiographic image reading apparatus, comprising:
image reading means for reading a radiographic image on a radiographic image conversion panel and for obtaining radiographic image information;
panel discriminating information reading means for reading panel discriminating information corresponding to the radiographic image conversion panel and for obtaining information regarding the radiographic image conversion panel; and
reading condition determining means for obtaining a reading condition to read radiographic image information stored in the radiographic image conversion panel on the basis of the information regarding the radiographic image conversion panel.
With the invention described in Items (7) and (8), since an image on a radiographic image conversion panel can be read on the condition corresponding to the radiographic image conversion panel, the radiographic image information more suitable for diagnosis can be obtained.
(9) A radiographic image reading method of reading a radiographic image on a radiographic image conversion panel and for obtaining radiographic image information; comprising steps of:
reading panel discriminating information corresponding to the radiographic image conversion panel, thereby obtaining information regarding the radiographic image conversion panel; and
eliminating a remaining image on the radiographic image conversion panel on the basis of the information regarding the radiographic image conversion panel.
(10) A radiographic image reading apparatus, comprising:
image reading means for reading a radiographic image on a radiographic image conversion panel and for obtaining radiographic image information;
panel discriminating information reading means for reading panel discriminating information corresponding to the radiographic image conversion panel and for obtaining information regarding the radiographic image conversion panel; and
eliminating means for eliminating a remaining image on the radiographic image conversion panel on the basis of the information regarding the radiographic image conversion panel.
With the invention described in Items (9) and (10), since noise remaining after an image on the radiographic image conversion panel is read can be eliminated on the eliminating condition corresponding to the radiographic image conversion panel, the radiographic image information on the radiographic image conversion panel photographed after the eliminating operation can be obtained as an image more suitable for diagnosis.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a flow chart showing how the radiographic image is read in the first embodiment of the invention.
FIGS. 2 ( a ) and 2 ( b ) each is an illustration showing how the panel discriminating information used in the embodiment of the invention is provided.
FIGS. 3 ( a ) and 3 ( b ) are structure diagrams showing the structure of a radiographic image reading apparatus used in the first embodiment of the invention.
FIG. 4 is a structure diagram showing the structure of a radiographic image reading apparatus used in the first embodiment of the invention.
FIG. 5 is a flow chart showing how the radiographic image is read in the second embodiment of the invention.
FIG. 6 is a structure diagram showing the structure of a radiographic image reading apparatus used in the second embodiment of the invention.
FIG. 7 is a structure diagram showing the structure of a radiographic image reading apparatus used in the second embodiment of the invention.
FIG. 8 is a structure diagram showing the structure to control a X-ray source on the basis of the panel discriminating information.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Next, embodiments of the invention will be explained as follows with reference to drawings.
(First Embodiment)
FIG. 1 is a flow chart showing procedures of the radiographic image reading method in the first embodiment of the invention. FIG. 2 is an illustration showing how the panel discriminating information is provided in the embodiment of the invention, and each of FIGS. 3 and 4 is a structure diagram showing an example of a radiographic image reading apparatus in the embodiment of the invention or of an apparatus conducting a radiographic image reading method in each embodiment of the invention.
In FIGS. 3 and 4, cassette 10 houses plural panels (radiographic image conversion panel) 11 , and the cassette 10 is inserted in a radiographing apparatus which is not shown in the drawing or in radiographic image reading apparatus 20 for conducting radiographing and reading.
Incidentally, in the present embodiment, there is explained an example wherein a radiographic image conversion panel is used as a radiographic image conversion means, and the radiographic image conversion panel is represented not only by a stimulative phosphor plate but also by a semiconductor detector.
Panel discriminating information corresponding to sensitivity of panel 11 is to be provided to each panel 11 as ID information section 12 as shown in FIG. 2 ( a ), or panel discriminating information corresponding to sensitivity of panel 11 is to be provided to each cassette 10 housing therein plural panels 11 as ID information section 12 as shown in FIG. 2 ( b ).
The ID information section 12 is represented by those wherein panel numbers, version information of the panel, sensitivity information of the panel, fading characteristics, and individual ID information of the panel are recorded on an information recording medium such as bar codes, magnetic stripes or IC memories.
Radiographic image reading apparatus 20 is one to read radiographic images and to prepare image data by reading radiographic image information formed on panel 11 through irradiation of radioactive rays transmitted through a subject.
Control section 21 is a control means to control operations of each section of the radiographic image reading apparatus 20 , and it conducts operation control concerning reading in accordance with inputted command from an unillustrated operation part or with a built-in operation control program.
The reading means is provided with excitation light generating section 22 which generates an excitation light such as a laser beam in the state of scanning and with reading section 23 which collects stimulated emission light on panel 11 to conduct photoelectric transfer.
The reading means is further provided with LOG amplifier 24 which voltage-amplifies an output (analog image signals) of the reading section 23 with prescribed characteristics and with A/D converter 28 which converts analog image signals into digital image data and outputs them as image data. There is further arranged driving section 29 which drives panel 11 at constant speed during reading under the control of the control section 21 .
When ID information section 12 is provided on panel 11 as panel discriminating information as shown in FIG. 2 ( a ), discriminating information reading means 25 such as a sensor for reading the ID information section 12 is arranged at the position corresponding to the panel 11 (FIG. 3 ).
When ID information section 12 is provided on cassette 10 as panel discriminating information as shown in FIG. 2 ( b ), discriminating information reading means 25 such as a sensor for reading the ID information section 12 is arranged at the position corresponding to the cassette 10 (FIG. 4 ).
Further, there are provided table 27 representing a storage means that stores, as a table, data of correspondence between panel discriminating information and panel information such as panel version, date of manufacture of panel, panel materials (semiconductor material, phosphor types), panel erasability, panel fading characteristics and panel sensitivity, and processing control section 26 that reads out information of panel 11 from the results of detection by discriminating information reading means 25 and from the table stored in table 27 .
Incidentally, correspondence data between panel discriminating information and panel sensitivity are stored in the table 27 , and an absolute value of sensitivity or a relative value of sensitivity (relative sensitivity for version 1.0) is stored as panel sensitivity. When an absolute value for sensitivity of panel 11 is recorded on ID information section 12 , it is also possible to omit the table 27 as shown in FIG. 3 ′. When material of panel 11 is stored in ID information section 12 , data corresponding to panel materials, panel sensitivity and panel erasability are stored in the table. In the same manner, panel information such as panel version, date of manufacture of panel, panel material, panel erasability, panel fading characteristics and panel sensitivity may be stored in ID information section 12 as panel discriminating information, and in that case, table 27 can be omitted. It is further possible to store panel numbers in ID information section 12 as panel discriminating information and to store in table 11 panel numbers, panel versions, dates of manufacture of panel, panel materials, panel erasability, fading characteristics of panel and panel sensitivity so that they may be corresponded.
Now, operations in the present embodiment will be explained as follows, referring to the flow chart in FIG. 1, with an example to correct panel sensitivity. First, panel discriminating information (ID information) based on sensitivity of panel 11 or on version is provided to cassette 10 housing panel 11 or to panel 11 (FIG. 1 Sl)
When providing panel discriminating information to panel 11 , a prescribed area which is outside the image forming area is determined to be ID information section 12 (see FIG. 2 ( a )), and a medium such as a bar code, a magnetic tape or a memory is pasted on the area so that panel discriminating information may be stored in the medium.
When providing discriminating information to cassette 10 , an area in the position which makes it easy to read when the cassette is inserted in radiographic image reading apparatus 20 is determined to be ID information section 12 (see FIG. 2 ( b )), and a medium such as a bar code, a magnetic tape or a memory is pasted on the area so that panel discriminating information may be stored in the medium.
In synchronization with this, a table wherein panel discriminating information is corresponded to panel sensitivity is stored in table 27 of radiographic image reading apparatus 20 as ID information (see FIG. 1 S 2 ).
Panel discriminating information to be provided in this case includes information of an absolute value of panel sensitivity, a sign corresponding to an absolute value of panel sensitivity, information of panel version, date of manufacture of panel and panel materials. In the table 27 , information of panel sensitivity corresponding to the panel discriminating information stated above (sensitivity change (relative sensitivity) for basic version, and sensitivity corresponding to the aforesaid sign) is stored.
Radiographing is conducted by the use of panel 11 or cassette 10 prepared as in the foregoing, and the cassette 10 housing therein exposed panels is inserted in radiographic image reading apparatus 20 for conducting reading (FIG. 1 S 3 ).
In the radiographic image reading apparatus 20 into which the cassette 10 is inserted, panel discriminating information on ID information section 12 on panel 11 or cassette 10 is read by discriminating information reading means 25 in the course of reading (FIG. 1 S 4 ).
With regard to the panel discriminating information read by the discriminating information reading means 25 , processing control section 26 calls sensitivity of panel 11 , referring to table 27 (FIG. 1 S 5 ). When sensitivity information of panel 11 is recorded on ID information section 12 , the information is used as it is, while when version information of the panel and signs corresponding to sensitivity are recorded, sensitivity of panel 11 is called with reference to table 27 .
In accordance with sensitivity of panel 11 thus called, reading conditions for reading radiographic image information accumulated in the panel 11 are set so that the conditions may be changed to initial values (FIG. 1 S 6 ).
Incidentally, the correction for the reading conditions includes gain adjustment of a photomultiplier tube of reading section 23 and adjustment of amplification factor of LOG amplifier 24 both carried out through control of the reading section 23 and the LOG amplifier 24 conducted by the processing control section. The correction and adjustment mentioned above are conducted so that a difference in signal values of radiographic image information caused by a difference in sensitivity of panel 11 may be canceled.
In this case, when gain adjustment is conducted on a photomultiplier tube, it is possible to make the distribution of signal values of panel 11 and a readable range for the photomultiplier tube to match each other, and thereby to use a dynamic range of the photomultiplier tube effectively, which is an advantageous point.
Under the state that the reading conditions are set as in the foregoing, reading of radiographic image information of panel 11 is conducted by excitation light generating section 22 and reading section 23 (FIG. 1 S 7 ). This reading makes it possible to obtain the constant signal value for the constant dose of X-rays independently of sensitivity of the radiographic image conversion panel. The foregoing is a method for correcting sensitivity prior to reading radiographic image information, and it is also possible to correct sensitivity through the method wherein the aforesaid S 6 is omitted, then reading is conducted in S 7 , and after that, the radiographic image information thus read is corrected. In this case, S 4 and S 5 may also be conducted after completion of S 6 .
Namely, in the case of the reading mentioned above, it does not happen that signal values are changed by a difference in sensitivity of radiographic image conversion panels. As a result, a level of the dose of irradiation can easily be judged and controlled. Further, a quantity of radioactive rays can easily be controlled, and thereby it does not happen that a patient is exposed to excessive radioactive rays.
In addition, even when radiographing for plural sheets under the condition that radiographic image conversion panels each having different sensitivity are present as a mixture to be used, it is possible to obtain radiographic images each having the same signal value when radiographing the same subject using the same quantity of X-rays. Therefore, a correct diagnosis can be made. In the same way as in the present embodiment, it is further possible to correct reading conditions resulting from fading characteristics and panel materials other than sensitivity.
When correcting fading characteristics, gain of reading section 23 or gain of LOG amplifier 24 is adjusted in accordance with fading characteristics, or light intensity of excitation light generating section 22 is adjusted in accordance with fading characteristics.
In the case of correction of reading conditions resulting from panel materials, sensitivity can be corrected through the present embodiment, and when an excitation wavelength varies depending on the kinds of materials, the excitation wavelength of the excitation light generating section 22 is changed for the correction. A method to change an excitation wavelength includes a method to employ a wavelength conversion element and a method provided with an excitation light generating section for plural wavelengths both of which can be selected in accordance with panel materials.
Next, there will be explained a method to update data in the table.
A table data inputting section 32 as a table data inputting means capable of inputting data wherein panel discriminating information and information concerning panels are made to correspond to each other, and a table data updating section 31 as a table data updating means which inputs table data inputted from the table data inputting means in table 27 and updates data in table are provided. By providing these, it is possible to make the aforesaid correction even when reading radiographic image information of a new panel which is not stored in the table.
As a table data inputting means, it is possible to use a driver which reads a storage medium such as a key board or a floppy disk. Further, a receiving means capable of receiving table data through telephone lines can save the time required for a user to input table data.
(Second Embodiment)
FIG. 5 is a flow chart showing procedures of a radiographic image reading method in the second embodiment of the invention. Each of FIGS. 6 and 7 is a structure diagram showing an example of a radiographic image reading apparatus in the second embodiment of the invention or an apparatus executing a radiographic image reading method in the second embodiment of the invention.
In FIGS. 6 and 7, items identical to those in FIGS. 3 and 4 are given the same numbers as the numbers in FIGS. 3 and 4, and explanation for them will be omitted here. The point of FIGS. 6 and 7 which is different from that in FIGS. 3 and 4 is that there is provided image memory 30 which temporarily stores radiographic image information as image data, wherein the image data are corrected by control section 21 .
Operations in the present embodiment will be explained here with reference to the flow chart in FIG. 5 . First, panel discriminating information (ID information) corresponding to sensitivity or version of panel 11 is provided to cassette 10 housing panel 11 or to panel 11 (FIG. 5 S 1 ).
When providing panel discriminating information to panel 11 , a prescribed area which is outside the image forming area is determined to be ID information section 12 (see FIG. 2 ( a )), and a medium such as a bar code, a magnetic tape or a memory is pasted on the area so that panel discriminating information may be stored in the medium. When providing discriminating information to cassette 10 , an area in the position which makes it easy to read when the cassette is inserted in radiographic image reading apparatus 20 is determined to be ID information section 12 (see FIG. 2 ( b )), and a medium such as a bar code, a magnetic tape or a memory is pasted on the area so that panel discriminating information may be stored in the medium.
In synchronization with this, a table wherein panel discriminating information is corresponded to panel sensitivity is stored in table 27 of radiographic image reading apparatus 20 as ID information (see FIG. 5 S 2 ).
Panel discriminating information to be provided in this case includes information of an absolute value of panel sensitivity, a sign corresponding to an absolute value of panel sensitivity and information of panel version. In the table 27 , information of panel sensitivity corresponding to the panel discriminating information stated above (sensitivity change (relative sensitivity) for basic version, and sensitivity corresponding to the aforesaid sign) is stored.
Radiographing is conducted by the use of panel 11 or cassette 10 prepared as in the foregoing, and the cassette 10 housing therein exposed panels is inserted in radiographic image reading apparatus 20 for conducting reading (FIG. 5 S 3 ).
In the radiographic image reading apparatus 20 into which the cassette 10 is inserted, radiographic image information of panel 11 is read by excitation light generating section 22 and reading section 23 , and panel discriminating information on ID information section 12 on panel 11 or cassette 10 is read by discriminating information reading means 25 (FIG. 5 S 4 ). In this case, the radiographic image information thus read is stored in image memory 30 as image data.
With regard to the panel discriminating information read by the discriminating information reading means 25 , sensitivity processing section 26 calls sensitivity of panel 11 , referring to table 27 (FIG. 5 S 5 ). When sensitivity information of panel 11 is recorded on ID information section 12 , the information is used as it is, while when version information of the panel and signs corresponding to sensitivity are recorded, sensitivity of panel 11 is called with reference to table 27 .
In accordance with sensitivity of panel 11 thus called, conditions under which the radiographic image information stored in image memory 30 is subjected to image processing are set (FIG. 5 S 6 ).
Incidentally, the correcting conditions in image processing include various conditions to cancel a difference in signal values of radiographic image information caused by a difference in sensitivity of panel 11 .
Under the state wherein correcting conditions in image processing are set as stated above, image data stored in image memory 30 are subjected to image processing conducted by an image data processing section 34 (FIG. 5 S 7 ). This image processing makes it possible to obtain image data with the constant signal value for the constant dose of X-rays independently of sensitivity of the radiographic image conversion panel.
Namely, when the reading and the image processing mentioned above are conducted, it does not happen that a signal value is changed by a difference in sensitivity of the radiographic image conversion panels. As a result, a level of the dose of irradiation can easily be judged and controlled.
In addition, even when radiographing for plural sheets under the condition that radiographic image conversion panels each having different sensitivity are present as a mixture to be used, it is possible to obtain radiographic images each having the same signal value when radiographing the same subject using the same quantity of X-rays. Therefore, a correct diagnosis can be made. In addition to the aforesaid correction of sensitivity, reading conditions resulting from fading characteristics and panel materials can also be corrected.
(Third Embodiment)
When panel 11 is represented by a stimulating phosphor panel, the erasing section 35 shown in FIG. 3 is driven by control section 21 to erase noises remaining on panel 11 , after radiographic image information has been read. In that case, processing control section 26 reads erasing conditions which are stored in table 27 to correspond to panel discriminating information, based on panel discriminating information on panel 11 , and it controls the erasing section so that erasing can be conducted based on the erasing conditions. As an erasing condition, there is used a parameter which changes erasing light quantity including erasing time and intensity of erasing light. Incidentally, in table 27 , either absolute values of erasing conditions or relative values for the standard erasing conditions may be stored, similarly to information relating to sensitivity in another embodiment.
When absolute values of erasing conditions are stored in ID information section 12 as panel discriminating information, table 27 may be omitted as shown in FIG. 4 .
(Fourth Embodiment)
An image display section 33 in FIG. 3 is a warning means for displaying an expiration date of panel 11 or for warning that the expiration date of panel 11 is over. Processing control section 26 reads out a date of manufacture or an expiration date of panel 11 stored in table 27 in a way to correspond to panel discriminating information, based on the panel discriminating information of the panel 11 . When the date of manufacture is read out, the processing control section calculates an expiration date from the date of manufacture. Then, the processing control section displays the expiration date on an image display section. When it is realized from the expiration date and a current date that the term of validity has expired, the expiration of the term of validity may be displayed on the image display section. It is also possible to provide a means to give warning orally for the expiration of the valid term, in place of the image display section.
When an expiration date is stored in ID information section 12 as panel discriminating information, the table 27 can be omitted as shown in FIG. 4 .
(Fifth Embodiment)
FIG. 8 shows an occasion where a radiation exposure device is controlled based on panel discriminating information.
Only difference between FIG. 8 and FIG. 3 will be explained.
Discriminating information reading section 25 reads ID information section before panel 11 is exposed to radiation. Then, processing control section 26 reads out radiation exposure conditions representing photographing conditions stored in table 26 to correspond to panel discriminating information, based on the read panel discriminating information. Based on the radiation exposure conditions thus read out, the processing control section 26 controls an X-ray source control section 36 of the radiation exposure device so that radiation may be irradiated. As radiation exposure conditions, a quantity of light of radiation and an absolute value of a quantity of light of radiation are used, and as a quantity of light of radiation, irradiation intensity and irradiation time are used. When absolute values of radiation exposure conditions are stored in ID information section 12 as panel discriminating information, table 27 may be omitted as shown in FIG. 4 .
As stated above, since photographing can be conducted on the condition corresponding to the radiographic image conversion panel on the basis of the panel discriminating information, radiographic image information on the radiographic image conversion panel obtained by the photographing becomes information in which image quality irregularities due to the difference among the radiographic image conversion panels are reduced so that the information becomes more suitable for diagnosis.
(Sixth Embodiment)
In the first embodiment, or in the fifth embodiment stated above, sensor 25 is arranged inside a cassette-insertion opening provided on radiographic image reading apparatus 20 . In contrast with this, a handy scanner representing the sensor 25 is used, and after an operator uses the handy scanner to read panel discriminating information, a cassette can be inserted in radiographic image reading apparatus 20 .
With the structure mentioned above, it is possible to use easily in the existing radiographic image reading apparatus by connecting the handy scanner to an input/output port and by correcting reading conditions and image processing with an operation program of control section (CPU) 21 .
(Seventh Embodiment)
In each embodiment stated above, when a plurality of radiographic image reading apparatuses are arranged through network connection, panel discriminating information can be shared by controlling table 27 with a server. By doing this, common panel discriminating information can be utilized, and panel discriminating information can be updated surely.
(Eighth Embodiment)
In the case of a radiographic image radiographing/reading apparatus having therein plural panels 11 , it is possible to carry out the foregoing by providing panel discriminating information such as panel ID to each panel 11 (see FIG. 2 ( a )), and by conducting sensitivity correction in reading and image data correction in the same way as in the aforesaid embodiment.
Even in the case of an apparatus having therein built-in panels, when radiographing for plural sheets under the condition that radiographic image conversion panels each having different sensitivity are present as a mixture to be used, it is possible to obtain radiographic images each having the same signal value when radiographing the same subject using the same quantity of X-rays. Therefore, a correct diagnosis can be made.
(Ninth Embodiment)
Even in the case of a radiographic image radiographing/reading apparatus having therein one sheet of panels 11 , it is possible to carry out the foregoing by providing panel discriminating information such as panel ID to the panel 11 (see FIG. 2 ( a )), and by conducting sensitivity correction in reading and image data correction in the same way as in the aforesaid embodiment.
In this case, it is also possible to update table 27 by the use of a floppy disk packed together with a panel when panel 11 is replaced, without providing ID information section 12 on panel 11 .
Even in the case of an apparatus having therein a built-in panel, when radiographic image conversion panels each having different sensitivity are used, it is possible to obtain radiographic images each having the same signal value when radiographing the same subject using the same quantity of X-rays. Therefore, a correct diagnosis can be made.
As explained in detail above, the invention described hereupon provides the effects described in Items (1) to (10).
In addition to Items (1) to (10) stated above, the objective of the present invention can be attained by the following Items as the preferable embodiment.
(11) A radiographic image reading method for reading a radiographic image conversion panel, wherein panel discriminating information provided to the radiographic image conversion panel in accordance with its sensitivity is read, then reading sensitivity is corrected based on the panel discriminating information, and radiographic image information is read from the radiographic image conversion panel.
In this radiographic image reading method, it is possible to obtain the constant signal value for the constant dose of X-rays independently of sensitivity of the radiographic image conversion panel, because radiographic image information is read from the radiographic image conversion panel after the reading sensitivity is corrected based on the panel discriminating information.
(12) A radiographic image reading method for reading a radiographic image conversion panel, wherein radiographic image information on a radiographic image conversion panel which is provided with panel discriminating information corresponding to sensitivity of the panel is read, and concurrently with that, the panel discriminating information is read, and the radiographic image information thus read is corrected based on the aforesaid panel discriminating information.
In this radiographic image reading method, it is possible to obtain the constant signal value for the constant dose of X-rays independently of sensitivity of the radiographic image conversion panel, because radiographic image information read is corrected based on the panel discriminating information.
(13) In the methods (11) and (12) above, panel discriminating information provided to the radiographic image conversion panel is read.
In the radiographic image reading method, correction of sensitivity or correction of image information is conducted based on the panel discriminating information provided to the radiographic image conversion panel. It is therefore possible to obtain the constant signal value for the constant dose of X-rays independently of sensitivity of the radiographic image conversion panel.
(14) In the methods (11) and (12) above, panel discriminating information provided to a cassette which houses the radiographic image conversion panel is read.
In the radiographic image reading method, it is possible to obtain the constant signal value for the constant dose of X-rays independently of sensitivity of the radiographic image conversion panel, because correction of sensitivity or correction of image information is conducted based on the panel discriminating information provided to the cassette which houses the radiographic image conversion panel.
(15) A radiographic image reading apparatus for reading a radiographic image conversion panel, wherein a radiographic image information reading means which reads radiographic image information accumulated on the radiographic image conversion panel, a panel discriminating information reading means which reads panel discriminating information provided to the radiographic image conversion panel in accordance with its sensitivity, a storing means in which correspondence data between panel discriminating information and sensitivity are stored, and a control means which controls reading sensitivity of the radiographic image information reading means based on sensitivity corresponding to panel discriminating information read by the panel discriminating information reading means, are provided.
In this radiographic image reading apparatus, radiographic image information is read from the radiographic image conversion panel after the reading sensitivity is corrected based on the panel discriminating information. It is therefore possible to obtain the constant signal value for the constant dose of X-rays independently of sensitivity of the radiographic image conversion panel.
(16) A radiographic image reading apparatus for reading a radiographic image conversion panel, wherein a radiographic image information reading means which reads radiographic image information accumulated on the radiographic image conversion panel, a panel discriminating information reading means which reads panel discriminating information provided to the radiographic image conversion panel in accordance with its sensitivity, a storing means in which correspondence data between panel discriminating information and sensitivity are stored, and an image processing means which corrects radiographic image information read by the radiographic image information reading means based on sensitivity corresponding to panel discriminating information read by the panel discriminating information reading means.
In this radiographic image reading apparatus, it is possible to obtain the constant signal value for the constant dose of X-rays independently of sensitivity of the radiographic image conversion panel, because radiographic image information read is corrected based on panel discriminating information.
(17) Structures (15) and (16) above, wherein the panel discriminating information reading means reads panel discriminating information provided to the radiographic image conversion panel.
In this radiographic image reading apparatus, it is possible to obtain the constant signal value for the constant dose of X-rays independently of sensitivity of the radiographic image conversion panel, because correction of sensitivity or correction of image information is conducted after reading panel discriminating information provided to the radiographic image conversion panel.
(18) Structures (15) and (16) above, wherein the panel discriminating information reading means reads panel discriminating information provided to a cassette which houses the radiographic image conversion panel.
In this radiographic image reading apparatus, it is possible to obtain the constant signal value for the constant dose of X-rays independently of sensitivity of the radiographic image conversion panel, because correction of sensitivity or correction of image information is conducted after reading panel discriminating information provided to the cassette that houses the radiographic image conversion panel.
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In a radiographic image reading method of reading a radiographic image on a radiographic image conversion panel and for obtaining radiographic image information; the adiographic image reading method includes steps of: reading panel discriminating information corresponding to the radiographic image conversion panel, thereby obtaining information regarding the radiographic image conversion panel; and applying image processing for the radiographic image information based on the information regarding the radiographic image conversion panel.
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CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the priority of German Patent Application No. 101 40 304.6 filed on Aug. 16, 2001, the disclosure of which is being incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] The invention relates to a device on a carding machine for cotton, synthetic fibers and the like. More particularly, the invention relates to flat bars with clothing, wherein the flat bars are positioned opposite clothing mounted on a roller, such as, for example, a main carding cylinder.
[0003] The flat bar of the device shown in U.S. Pat. No. 3,151,362 has a back piece and a support body with an underside. A clothing strip is attached to the underside and extends in a longitudinal direction of the flat bar. The clothing strip has a support element with several textile layers having a plurality of wire hooks embedded therein. The clothing strip is attached with at least two clamps extending over the longitudinal sides of the support body. With one end, the clamps encircle the edge regions of the clothing strip in the longitudinal direction while they engage with the other end in recesses of the support body. In practical operations, the clamps are fashioned from sheet-metal strips, one longitudinal edge of which is pushed into the textile material. During assembly, the textile material of the clothing strip is attached with considerable tension and form-fitted to the support body of the flat bar. In the process, the clamps exert tensile forces, such that the textile material is spherically deformed away from the flat bar underside. This results in the clothing wire points being arranged in an undesirable manner pointing outward on a convex enveloping curve. A set of such flat bars has a height fluctuation of, for example, 0.05 mm when not in use. When in use, however, the height differences can increase to approximately 0.2 mm. Re-sharpening the clothing point on the machine only results in an insignificant improvement of the accuracy. Following a throughput of approximately 400 tons of fiber material, the flat bar clothing is worn out to the point that it must be replaced. To dismantle the sheet metal straps, the flat bar is clamped down and the form-fitting connection is reversed with the aid of a lever and pliers. The considerable forces required during the assembly and dismantling negatively affect the dimensional stability of the flat bar. Undesirable production tolerances for the flat bar body compound these dimensional inaccuracies. As a result of the aforementioned disadvantages, the clothing wire points of the clothed flat bar must be leveled by grinding them down.
[0004] Modern flat bars are made of aluminum and are extruded. During practical operations, the extruded flat bar is then cut to size and is leveled, for example to within 0.05 mm of flat. Support pins are subsequently glued into openings on the side of the support body, over a partial region in a tolerance-free plane. Height fluctuations for the glued-in pins result due to the extrusion process and the leveling operation. To keep the height difference for a flat bar set to within 0.05 mm of each other, the bars are sorted according to their height following pin gluing. This operation is time consuming. The clothing strip is then mounted to the underside of the flat bar in the above-described manner. The total height difference when adding the tolerances of the flat bar, the flat bar clothing, the offset during assembly, and the deformation caused by tensioning when mounting the clothing is significant. As a result, the previously described leveling grinding is carried out across all the flat bars after assembly. In the process, up to 0.15 mm is ground off, thus reducing the technological effectiveness of the ground-down, clothing wire points. During the grinding-down operation, the actual operational precision in the region of the wire points is removed from the clothing wire. The addition of the tolerances during the assembly of the flat bar clothing, the technologically damaging leveling grinding, and wear during use represent particular disadvantages in these machines.
SUMMARY OF THE INVENTION
[0005] Thus, it is an object of particular embodiments of the invention to create a device of the aforementioned type that avoids the above-mentioned disadvantages and, in particular, allows for an easy production of an inherently stable flat bar with clothing.
[0006] Embodiments of the invention include a flat bar assembly for use with a carding machine having a carding cylinder, the carding cylinder having clothing. The assembly has a flat bar, flat bar clothing attached to the flat bar, and an equalizing layer between the flat bar and the flat bar clothing. The flat bar clothing is for positioning opposite the carding cylinder clothing, and the equalizing layer fills a space between the flat bar and the flat bar clothing to compensate for distance differences between the flat bar clothing and the flat bar and to locate the flat bar clothing at a predetermined position relative to the flat bar.
[0007] An inherently stable flat bar can be produced easily by arranging an equalizing layer between the flat bar and the flat bar clothing to compensate for differences in the distance between the two. All production tolerances of the flat bar, the clothing and those occurring during the assembly (including the dismantling) are compensated for. The clothed flat bar according to the invention advantageously avoids the addition of tolerances resulting from the assembly and dismantling of the flat bar clothing, the technologically damaging leveling grinding and uneven wear during use.
[0008] The equalizing layer advantageously equalizes the distance differences between the rear surface of the clothing and the underside of the flat bar. The equalizing layer can preferably locally equalize distance differences between the rear surface and the underside. The flat bar forms a component of a set of traveling flats and is locally secured. A flexible clothing is provided and preferably comprises a support and clothing wire points, wires, hooks or the like. The support is strip-shaped and the clothing preferably consists of sawtooth wire strips, e.g. all-steel clothing. The clothing is attached in the region of the flat bar underside and is preferably glued to the flat bar. The equalizing layer preferably consists of a synthetic material or the like. This equalizing material can be a synthetic resin, such as epoxy resin. Polyester or a similar material is preferred for the equalizing material. The synthetic material, the synthetic resin, or the like should harden and should preferably be pourable. It is furthermore useful if the synthetic material, the synthetic resin, or the like, is adhering and preferably adheres more to the clothing support than to the underside of the flat bar. An adhesive layer can be provided between the equalizing layer and the underside of the flat bar, preferably in the form of an adhesive foil. It is useful if at least one side of the adhesive foil is sticky. The equalizing layer or the adhesive can be detachable and should preferably be water-soluble. A soluble lacquer or the like is preferably provided for the equalizing layer and the adhesive. Preferably, the equalizing layer and the adhesive can be removed without residue from the underside of the flat bar. The underside of the flat bar is preferably provided with an equalizing step. The flat bar and the flat bar clothing can be aligned to the same reference plane, preferably a plane across the tips of the flat bar clothing. It is useful if the flat bar is an extruded profile made of a lightweight metal, e.g. aluminum, and is preferably a hollow profile. The correct length of the flat bar is cut and then preferably leveled. Two end parts (flat bar heads) are preferably aligned at the ends to the support body. These two end parts are preferably pins, made of hardened steel or a similar material, which are fastened in recesses of the support body. The support element (textile material) and the equalizing layer are preferably arranged in a recess on the underside of the flat bar and/or on the support body. The recess can be delimited by at least two ridges along the longitudinal sides of the support body. The support body preferably has inlet openings, e.g. through bores, for filling in the equalizing layer material. It is advantageous if the distance between sliding surfaces of the flat bar heads and a curve defined by the flat bar clothing wire points is the same.
[0009] An apparatus to assist the assembly of the flat bar assemblies has a flat plate and a bearing element. The plate is preferably a magnetic plate. The flat bar heads rest on a reference plane, and the plate and the reference plane are preferably attached to the bearing element. Two reference planes are oriented parallel to each other and the distance between these reference planes should be adjustable. It is advantageous if the flat bar clothing points rest on one reference plane, the flat bar heads on the other reference plane and the intermediate layer is inserted between the support body and the clothing strip. An adhesive strip is preferably inserted between the intermediate layer and the underside of the support body. The adhesive strip is preferably sticky on two sides. The support element preferably has at least one fastening plate, for example of metal, which is attached with a screw or the like to the flat bar. The adhesive strip preferably has a shackle or the like. The width of the adhesive strip and the adhesive equalizing layer is preferably wider than the width of the support body, the equalizing layer and/or the support element.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The invention is explained further in the following description with the aid of exemplary embodiments shown in the drawings, wherein like reference numbers denote like elements, and wherein:
[0011] [0011]FIG. 1 is a schematic side elevation view of a carding machine provided with a device according to the invention;
[0012] [0012]FIG. 2 shows clothed flat bars in accordance with the invention;
[0013] [0013]FIG. 3 a is a side elevation view of a flat bar with a portion of the back piece, the support body and the pins in the flat bar heads;
[0014] [0014]FIG. 3 b is a side elevation view through a clothing strip;
[0015] [0015]FIG. 3 c is a side elevation view of a flat bar and a clothing strip according to FIGS. 3 a and 3 b, assembled and including an equalizing layer;
[0016] [0016]FIG. 4 shows a device with two reference planes for orienting the flat bar to install the equalizing layer;
[0017] [0017]FIG. 5 shows a self-gluing equalizing layer;
[0018] [0018]FIG. 6 shows an adhesive strip between the support body and the equalizing layer;
[0019] [0019]FIG. 7 a is a side elevation view of another embodiment of the invention;
[0020] [0020]FIG. 7 b is a partial front elevation view of the embodiment shown in FIG. 7 a;
[0021] [0021]FIG. 8 shows an embodiment of the invention with a fastening plate; and
[0022] [0022]FIGS. 9 and 10 show an embodiment of the invention with an extended adhesive strip.
DETAILED DESCRIPTION OF THE INVENTION
[0023] [0023]FIG. 1 shows a carding machine, for example a high performance carding machine DK 903 by the company Trützschler, Mönchengladbach, Germany. The carding machine has feed roller 1 , feed table 2 , licker-ins 3 a, 3 b, 3 c, main carding cylinder 4 , doffer 5 , stripping roller 6 , crushing rollers 7 , 8 , sliver guide element 9 , web trumpet 10 , withdrawing rollers 11 , 12 , traveling flats 13 with clothed flat bars 14 , can 15 , and can holder 16 . Curved arrows indicate the rotational directions for the rollers while the arrow A refers to the operating direction. The fixed carding elements 33 and 34 are arranged opposite the main carding cylinder clothing 4 a.
[0024] According to FIG. 2, a flexible bend 17 , provided with several adjustment screws (not shown), is mounted on each side of the carding machine on the side of the machine frame. The flexible bend 17 has a convex outer surface 17 a and a bottom surface 17 b. A sliding guide 20 , made, for example, of a sliding plastic, with convex outer surface 20 a and concave inner surface 20 b, is located above the flexible bend 17 . The concave inner surface 20 b rests on the convex outer surface 17 a and can glide on this surface in the direction of arrows B, C. Each flat bar 14 , for example shaped as disclosed in European Patent 0 567 747 Al, has a back piece 14 a and a support body 14 b. As shown in FIG. 3 a, the support body 14 b has a bottom surface 14 c, two side surfaces 14 d, 14 e, and two upper surfaces 14 f, 14 g (see FIG. 3 a ). Each flat bar 14 is provided with one flat bar head 14 ′, 14 ″ on each end (see FIG. 7 b ). Flat bar head 14 ′ has two steel pins 14 1 , 14 2 and flat bar head 14 ″ has two steel pins 14 3 , 14 4 . A portion of each pin is fastened (for example, glued) in an axial direction (along length 1 in FIG. 7 b ) in recesses 33 a, 33 b of the support body 14 b (see FIG. 7 b ). The sections of steel pins 14 1 , 14 2 (see FIG. 7 b ) that project over the frontal surfaces of support body 14 b slide along the convex outer surface 20 a of the sliding guide 20 in the direction of arrow D (see FIG. 2). The clothing strip 18 is attached to the underside of the support body 14 b. Wire points 19 ′ of the flat bar clothing 19 (see FIG. 3 b ) define a circle 21 (see FIG. 2). The main carding cylinder 4 is provided with cylinder clothing 4 a, for example, a sawtooth clothing, along its circumference. The points of the main carding cylinder clothing 4 a define a circle 22 . A distance a between the circle of points 21 and the circle of points 22 can be, for example, 3/1000′. The distance between the convex outer surface 20 a and the circle of points 22 is indicated by reference character b, while the distance between the convex outer surface 20 a and the circle of points 21 is indicated by reference character c. The radius for the convex outer surface 20 a is r 1 and the radius for the circle of points 22 is r 2 . The radii r 1 and r 2 intersect at the center M of the main carding cylinder 4 .
[0025] [0025]FIG. 3 a shows (exaggerated in the drawings) that the vertical distance d 1 , between the sliding point of pin 14 1 and the underside 14 c, and the vertical distance d 2 , between the sliding point of pin 14 2 and the underside 14 c, are different. This difference results in the underside 14 c being arranged at angle α relative to the vertical center line 35 through the support body 14 b. As shown in FIG. 3 b, the clothing strip 18 consists of clothing wire points 19 ′ (wire hooks) and a support element 23 of, for example, a textile material. The support element 23 has an upper surface 23 ′, a lower surface 23 ″, and a thickness f. The clothing wires 19 project with one end through the lower surface 23 ″, and are fastened to the support element 23 . The other ends of the clothing wires 19 , the clothing wire points 19 ′, are free. As shown in FIG. 3 c, an intermediate layer 24 , e.g., consisting of hardened synthetic resin, is arranged between the support body 14 b and the support element 23 . The top surface 24 ′ of intermediate layer 24 is positioned such that it makes contact with the underside 14 c of support body 14 b. Lower surface 24 ″ of intermediate layer 24 is positioned such that it makes contact with the upper surface 23 ′ of the support element 23 . The top surface 24 ′ is also arranged at the angle α relative to the vertical center line 35 through the support body 14 b. The lower surface 24 ″ is oriented parallel to the connecting line between the sliding points for pins 14 1 , 14 2 and a tangent of the circle of points 21 . As a result, the distance c between the sliding points for pins 14 1 , 14 2 (on the sliding surface 20 a ) and the circle of points 21 is the same for both pins 14 1 , 14 2. The equalizing layer 24 equalizes the distance differences e 1 , e 2 between the surfaces 14 c and 23 ′. Thus, despite the undesirable slanted course of the underside 14 c of support body 14 b, the important and narrow carding distance a between the circle of points 21 on the flat bar clothing 19 and the circle of points 22 on the main carding cylinder clothing 4 a remains constant for all locations. A connecting element 14 3 is attached to the pins 14 1 , 14 2 .
[0026] The equalizing layer 24 also equalizes local irregularities on the underside 14 c of support body 14 b and/or the upper surface 23 ′ of support element 23 . The equalizing layer 24 also equalizes deviations in the distances between the circle of points 21 and the upper surface 23 ′ and/or the lower surface 23 ″.
[0027] According to FIG. 4, two ridges 14 h, 14 i are attached to the support body 14 b on the side in a longitudinal direction. These can be welded on, for example, so that a recess 14 j is created in the region of the underside 14 c. As a result, the flat bar clothing 18 is protected and embedded.
[0028] For the production of clothed flat bar 14 , the flat bar wire points 19 ′ of the clothing strip 18 are placed onto a level surface 25 a of a metal plate 25 , for example, a magnetic plate. The flat bar heads 14 ′, 14 ″ with pins 14 1 , 14 2 , 14 3 , 14 4 are then placed onto a top surface 27 a of an adhering holding element 27 , e.g., a flat iron or the like. Following this, the adhering equalizing layer 24 is deposited on the upper surface 23 ′ of support element 23 . Finally, the holding element 27 is lowered (defined in the direction of arrow E) on the bearing element 26 by means of a drive (not shown herein) and onto the equalizing layer 24 . The drive can also raise holding element 27 in the direction of arrow F. In the process, the bottom surface 14 c is glued to the top surface 24 ′ (see FIG. 3c). If necessary, pressure can additionally be exerted via the bottom surface 14 c onto the top surface 24 ′ by, for example, exerting pressure onto the support body 14 b or the back piece 14 a.
[0029] [0029]FIG. 5 shows an example of an adhesive equalizing layer 24 made of a voluminous adhesive tape, or the like, which can be compressed differently with respect to its height. The adhesive tape is adhesive on two sides, meaning it adheres to the underside 14 c of support body 14 b and the upper surface 23 ′ of support element 23 .
[0030] [0030]FIG. 6 shows a thinner adhesive tape 28 provided between the support body 14 b and the equalizing layer 24 . The strip can adhere with one side to the underside 14 c or with two sides to the underside 14 c and the top surface 24 ′. The equalizing layer 24 can be fixed to the support element 23 , if necessary, such that it cannot be detached. The advantage of the adhesive strip 28 is that the connection between support body 14 b and the equalizing layer 24 can be broken easily for replacing the clothing strip 18 by, for example, simply pulling off the adhesive strip 28 . This allows a clothing strip 18 , with worn-out clothing 19 , the support element 23 , the equalizing layer 24 , and the adhesive strip 28 , to be simply discarded and replaced.
[0031] [0031]FIG. 7 a shows the holding element 27 ′, provided with a small step 29 (of, for example, 0.4 mm) between the pins 14 1 , and 14 2 , designed to balance the so-called rack. FIG. 7 b shows that a square support element 27 a with parallel and level surfaces and a height h is arranged between the flat bar pins 14 1 , 14 2 and the plate 25 . An additional square support element 27 b with the same height h is arranged between the flat bar pins 14 3 , 14 4 and the plate 25 . Elements 27 a, 27 b are fixed locally onto the plate 25 . With this device and additional ridge elements on the side (not shown herein) or the like (e.g. movable limiting surfaces for the equalizing layer 24 and/or the support element 23 ), the clothing wire points 19 ′ of the clothing strip 18 can be positioned on the plate 25 , and the flat bar 14 , with pins 14 1 , 14 2 , 14 3 , 14 4 , can be positioned on the support elements 27 a, 27 b. The equalizing layer 24 is subsequently inserted between the support body 14 b and the support element 23 . This layer can be inserted, for example, by pouring it in, injecting it, inserting it, manually applying it, or the like. The equalizing layer 24 , which may have the consistency of dough, spreads through and fills the intermediate space.
[0032] A solid equalizing layer 24 , e.g., a plastic strip, that is initially connected securely to the support element 23 can also be used. With such a solid equalizing layer, the support body 14 b is placed, if necessary, under pressure, onto the equalizing layer 24 . In the process, the support body can be heated so that the equalizing layer 24 is melted onto the underside 14 c. The underside 14 c can be structured, for example, with recesses, raised areas, holes, or the like, for attaching the equalizing layer 24 . The underside 14 c of the support body 14 b can be heated up using different methods, e.g., inductively or contact heat.
[0033] According to another embodiment of the invention, as shown in FIG. 8, the flat bar 14 that is provided with side ridges 14 h, 14 i on the underside is used as a casting mold. For example, casting resin is poured between the flat bar 14 and the clothing strip 18 . The back piece 14 a of the flat bar 14 is provided with several bores 30 across its length. Screws 31 extend through these bores and engage in threads in fastening plates 32 , made, for example, of metal. The flat bar 14 is provided with a separation means before the resin is poured in, so that that the clothing strip 18 can be replaced once it is worn.
[0034] In the embodiments shown in FIGS. 9 and 10, the adhesive strip 28 , which can be reinforced with a textile insert (hardened fiberglass or the like), is extended in at least one of its edge regions to match the width k (see FIG. 7 a ) of support body 14 b, the equalizing layer 24 , and/or the support element 23 . This forms shackle 28 a. The shackle 28 a, the length of which is shown in FIG. 9 as g and in FIG. 10 as i, can be grabbed separately at a later date with the aid of tongs or the like. This facilitates severing the connection between the bottom surface 14 c and the cooperating surface of the adhesive strip 28 , which permits the adhesive strip 28 , together with the equalizing layer 24 and the clothing strip 18 , to be pulled off or detached from the support body 14 b.
[0035] The invention has been described in detail with respect to preferred embodiments, and it will now be apparent from the foregoing to those skilled in the art, that changes and modifications may be made without departing from the invention in its broader aspects. The invention, therefore, is intended to cover all such changes and modifications that fall within the true spirit of the invention.
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A flat bar assembly is provided for use with a carding machine having a carding cylinder, the carding cylinder having clothing. The assembly has a flat bar, flat bar clothing attached to the flat bar, and an equalizing layer between the flat bar and the flat bar clothing. The flat bar clothing is for positioning opposite the carding cylinder clothing, and the equalizing layer fills a space between the flat bar and the flat bar clothing to compensate for distance differences between the flat bar clothing and the flat bar and to locate the flat bar clothing at a predetermined position relative to the flat bar.
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This is a continuation of application Ser. No. 143,983 filed Apr. 28, 1980, abandoned.
BACKGROUND OF THE INVENTION
This invention relates to heating of SiO 2 -based material in the semiconductor art.
The phosphosilicate glass flow process is used primarily to round off sharp edges of etched cuts on phosphosilicate glass to help prevent cracking at the edges of subsequently deposited metal or polycrystalline silicon fill and also to smooth the overall surface of a layer of phosphosilicate glass for subsequent controlled etching thereof. The flow process is normally induced by high temperature (approximately 950° C. or above) furnace anneal.
In general, the phosphosilicate glass layer is part of a structure initially formed by providing a silicon substrate with a thermally deposited silicon dioxide (SiO 2 ) layer thereon. A layer of P 2 O 5 -SiO 2 is then chemically vapor deposited on the layer of thermally deposited SiO 2 by, for example, reaction of a phosphorous-silane mixture and oxygen at low temperature, so that a top layer of phosphosilicate glass is provided.
A major problem with the prior art approach of inducing flow by high temperature anneal is that when device structures, i.e., structures which may be of material in close proximity to the phosphosilicate glass, are heated to a relatively high temperature in the furnace, their properties often undesirably change due to dopant diffusion, alloying and contamination. Another problem is that P 2 O 5 , typically in the concentration of 7-9 mol %, must be added to the SiO 2 base composition to lower the flow temperature. This subsequently enhances corrosion of the metal interconnections.
SUMMARY OF THE INVENTION
It is accordingly an object of the invention to provide a highly efficient method of inducing densification and/or flow of phophosilicate glass or the like so as to overcome the problems set forth above.
Broadly stated, the invention comprises a method of inducing flow or densification of a first, SiO 2 -based portion of a structure in close proximity to a second portion of the structure, the first portion being of the type wherein flow or densification is induced therein upon application of heat thereto, comprising heating the first portion to an extent substantially greater than the second portion.
Broadly stated, the invention also comprises a method of inducing flow or densification of a first portion of a structure in close proximity to a second portion thereof and of the type wherein flow or densification is induced therein upon application of heat thereto, comprising applying a laser beam to the first portion to heat the first portion.
BRIEF DESCRIPTION OF THE DRAWINGS
Other objects will become apparent from a study of the following specification and drawings, wherein:
FIG. 1 is a schematic cross section of a semiconductor structure being treated with a laser beam.
FIG. 2 is a view similar to FIG. 1 but showing a smooth cavity in the surface of the semiconductor structure.
FIG. 3 is a view similar to FIGS. 1 and 2 but showing the surface of the semiconductor structure after the structure of FIG. 2 has been etched to form a concavity with sharp edges.
FIG. 4 is a view similar to FIG. 3, but showing the concavity after being heated with a laser beam to smooth the sharp edges of the concavity.
FIG. 5 is a view similar to FIGS. 1-4 but showing a complete device with metal contacts deposited over the smooth edges.
FIG. 6 is a graphical view of a theoretical temperature profile of phosphosilicate glass as a function of incident power density for a 10 -3 second laser pulse or dwell time corresponding to pulsed or Q-switched and continuous wave (CW) laser modes, respectively.
DESCRIPTION OF THE PREFERRED EMBODIMENT
As explained above, FIGS. 1-5 illustrate the steps of the present invention. As shown in FIG. 1, a semiconductor structure 10 typified by an MOS device includes a first, SiO 2 -based portion 12 which is in the form of vapor deposited silicon oxide, grown phosphosilicate glass, which is in close proximity to a second structure portion 14. The second portion includes a silicon substrate 16 having a source/drain portion 18 formed therein, an oxide region 20, and a polycrystalline silicon interconnect 22. Isolation oxide 24 is also included. Typically, the direction "A" may be of the order of 1.0-1.5 μm, the dimension "B" may be of the order of 0.4 μm-0.6 μm, and the dimension "C" may be of the order of 0.4 μm-0.6 μm.
As described above, and as will be further described, it is desirable to apply heat to the phosphosilicate glass 12 to induce densification and/or flow thereof. As also discussed above, it will be seen that it is desirable to maintain the portion 14 at a relatively low temperature so as to avoid undesired dopant diffusion, alloying, and/or contamination.
The basis for the present process is the SiO 2 absorption maxima centered at about 1080 cm -1 (approximately 240 cm -1 band width FWHM) with an absorption coefficient of about 3×10 4 cm -1 . This absorption band is well suited for coupling to the 9.261 μm (1080 cm -1 ) emission of a suitable CO 2 scanning laser as shown at 30, which may be for example a Model 560 CO 2 gas laser as manufactured by Apollo Lasers, Inc., 6357 Arizona Circle, Los Angeles, CA 90045. For the composition SiO 2 up to 20 mol % P 2 O 5 , the 1080 cm -1 absorption band decreased monotonically with an increase in mol % of P 2 O 5 . Comparable concentrations of B 2 O 3 , As 2 O 5 or Sb 2 O 5 in SiO 2 will exhibit similar absorption characteristics. Additions of Si 3 S 4 to SiO 2 will also behave similarly. Thus, any SiO 2 based material with a greater than approximately 80 mol % SiO 2 , whether it be crystalline or amorphous, can be effectively coupled to the output of a CO 2 gas laser, and preferably one which is tunable.
At the wavelength under consideration, metallization has exhibited reflecting losses greater than about 95%, so that essentially no heat conduction thereby takes place. Also, the large thermal conductivity of metallization will act as a heat sink, pulling heat away from the active device. For silicon such as the substrate material 16, absorption occurs via photoexcitation of free carriers with a small contribution due to multi-phonon excitation. The absorption is in proportion to the dopant concentration and inversely proportional to the carrier mobility. Therefore, the coupling efficiency is significantly lower for both metal and silicon relative to SiO 2 -based material 12.
The temperature T in a solid heated by a laser beam of incident intensity I o is given [1] as: ##EQU1## where D is the thermal diffusivity, ρ is the mass density, C p is the specific heat, R is the reflectivity, α is the absorption coefficient, Z is the coordinate parallel to the incident radiation, and ##EQU2## where X, Y and Z are the cartesian coordinates of the solid. In the case of laser induced phosphosilicate glass flow, α -1 <<(2Dt) 1/2 , so that heat is created essentially at the surface and transported into the bulk by heat conduction. Assuming D, C p , and R to be temperature invariant, I to be spatially and temporally uniform, and that no latent heat due to phase transitions is involved, the solution to Eq. [1] is: ##EQU3## where T o is the initial temperature, and T(Z,t) is the temperature at a point Z and time, 0≦t≦t I , where t I is the pulse width or the dwell time of the incident radiation.
For phosphosilicate glass, the following material constants are assumed:
D=6×10 -3 cm 2 sec -1
p=2.27 g cm -3
C p =1.0 J g -1 °C. -1
R=0.525
Under these conditions, in FIG. 6 is plotted the calculated temperature profile, T(Z,t)-T o as a function of Z, for t=0.001 sec and I o =10, 11, 12 and 13 MW cm -2 . These curves suggest that for phosphosilicate glass thicknesses greater than about 1 μm, large thermal gradients will exist which maintain the surface of the substrate at a relatively cool temperature during flow. Within the normal phosphosilicate glass thickness range of 0.5 to 1.5 μm, FIG. 2 suggests that maximum phosphosilicate glass thickness will be optimal for this purpose and that a significant increase in thickness will not be beneficial. In support of this, consider that 12 MW cm -2 will produce a surface temperature of 1156° whereas the temperature at depths of 0.98, 1.47, and 2.45 μm will be 792°, 664° C., and 409° C., respectively. The underlying portion 14 is then never subjected to elevated temperatures.
If the substrate is heated, it will be noted that T o is increased, and the power density necessary to provide a certain T(Z,t)-T o decreases.
It should be recognized that the present method has the most significant advantage that the portion 12 can be induced to flow and/or densify by application of heat thereto through use of the laser 30, but with it being understood that the portion 12 is heated to an extent substantially greater than the portion 14. As discussed above, it will be seen that the surface of the phosphosilicate glass 12 can be heated to an elevated temperature, whereas the phosphosilicate glass at a depth of about 1.47 μm will be heated to a much lower temperature.
The result of the method described above is shown in FIG. 2. It will be seen that a great degree of smoothing of the surface 13 of the phosphosilicate glass 12 has been achieved. This is highly desirable for purposes of etching since the placement of the etching window defined by well-known photoresist techniques can be accurately achieved. This is to be compared with FIG. 1, wherein, if etching was to take place without such flow, the photoresist edges would have to be placed approximately where the "shoulders" 13A, 13B are defined by the phosphosilicate glass 12. Also, because of the relatively smooth shape of the phosphosilicate glass 12 as shown in FIG. 2, the etching can be controlled as chosen to a higher degree.
The result of such etching of the FIG. 2 structure is shown in FIG. 3. It is to be noted that while etching down to the substrate 16 in the chosen place and in the chosen manner has been achieved, sharp corners 13C, 13D are now defined by the phosphosilicate glass 12. The process as described above is again undertaken in the same manner, causing the phosphosilicate glass 12 to again flow, so as to smooth all the phosphosilicate glass surface 13 as shown in FIG. 3, and in particular to smooth the corners 13C, 13D shown in FIG. 3. The resulting structure is shown in FIG. 4.
The smoothing of the phosphosilicate glass 12 into the form shown in FIG. 4 allows for the proper placement of the aluminum leads 32, 34 as shown in FIG. 5, it being noted that FIGS. 1 through 4 have in fact shown the process as undertaken on the right-hand half of the structure of FIG. 5, which will readily be seen to be an MOS device. It is thus insured that cracking of the aluminum leads 32, 34 will not take place.
It is to be understood that although an MOS structure is shown in the illustration of the present process, such process can readily be used in bipolar structures. As also discussed above, the process is intrinsically independent of the mol % of P 2 O 5 , As 2 O 5 , or B 2 O 3 up to about 20 mol %.
Through the use of a laser as described above, it will also be seen that extremely small areas can be made to flow as desired.
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A tunable CO 2 gas laser is used to selectively heat various SiO 2 -based materials to elevated temperatures while maintaining an active device region at relatively low temperatures, to, for example, induce densification and/or flow of the SiO 2 -based material to round off sharp edges and stops.
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FIELD OF INVENTION
[0001] The present invention is concerned with the treatment of xerostomia, in particular, with solid pharmaceutical preparations used in the treatment of xerostomia.
BACKGROUND OF THE INVENTION
[0002] A reduced salivary secretion may arise or develop with increasing age. Thus, a large number of elderly people have problems with a dry mouth. Some general diseases also give rise to a reduced secretion of saliva, so called hyposalivation. The most prominent one thereof is Sjoegren's syndrome. Furthermore, several generally used medicines, inter alia, anti-hypertensives, anti-ulcer agents and anti-psychotics, have side effects including hyposalivation. Reduced salivary gland function may also accompany or follow a variety of anti-cancer treatments including radiotherapy and chemotherapy. In other words dryness of the mouth, or xerostomia, is a common disease that affects a large number of the population transiently or permanently. The reduced secretion of saliva can cause a variety of subjective symptoms including discomfort of of the tongue, mouth, pharynx and upper esophagus, sensitivity to spicy food and beverages and loss of sleep. Some individuals also have their speech and swallowing affected.
[0003] Objectively dryness of the mouth often causes caries and periodontitis, which are difficult to treat since the reduced secretion of saliva results in a more pronounced retention of bacteria in the oral cavity and on the teeth. The resistance of the mucosa against colonization of bacteria is reduced and especially fungal infections are common in connection with individuals with xerostomia. Furthermore, people carrying a plate prosthesis often have great problems with the retention of the prosthesis as well as infection of the mucosa as consequences of the dryness of the mouth. Other objective signs may include halitosis and recurrent ulcers in the mouth and oropharynx. Natural saliva consists of highly specialized proteins, which are strongly surface-active. They thus form surface films at interfaces of solids and also at soft tissues such as the surfaces of the oral cavity. This film also functions as a lubricant.
[0004] U.S. Pat. No. 5,260,282 discloses a saliva substitute comprising water-soluble linseed polysaccharides. Said substitute is presented in the form of an aqueous solution. The substitute can be prepared by extracting the polysaccharides from linseed by means of water or a water solution containing inorganic salts.
[0005] The types of saliva substitutes, such as those described above, consists of polysaccharides, often chemically modified natural products such as cellulose derivatives, for example carboxymethyl cellulose. They provide viscosity, but only very limited surface activity. The extraction procedure used to prepare linseed extract gives beside polysaccharides a considerable amount of proteins. These proteins are also quite surface active as seen by adsorption measurements. Linseed extract can emulsify oil and this is also a desired property of a saliva substitute, since oils in the food must be dispersed into water phase
SUMMARY OF INVENTION
[0006] In accordance with the present invention, there is provided a water-soluble or water-dispersible linseed extract characterised in that the extract has an absorption of at least 1.2 g/m 2 wherein the adsorption is measured by contacting an aqueous solution or dispersion of the extract with a silica substrate, rinsing the silica substrate and then measuring the adsorption by ellipsometry.
[0007] There is further provided a pharmaceutical composition which comprises a linseed extract according to the invention and a pharmaceutically acceptable excipient.
[0008] In accordance with a further aspect of the present invention, there is provided a process for the production of a water soluble or water dispersible linseed extract which process comprises spray drying or freeze drying an aqueous solution or dispersion of a linseed extract.
[0009] In accordance with a further aspect of the present invention, there is provided an aqueous pharmaceutical preparation obtainable by dissolving or dispersing a composition according to the invention in a solvent comprising water.
[0010] In a further aspect of the present invention, there is provided a method of treating xerostomia comprising administering a therapeutically effective amount of a linseed extract according to the invention or of a composition according to the invention to a patient in need of such treatment. The extract or composition is preferably administered orally.
[0011] According to the invention there is further provided use of an extract according to the invention or of a composition according to the invention in the manufacture of a medicament for use in the treatment of xerostomia.
[0012] The salivary glands of the mouth normally produce around 1-1.5 litres of saliva per 24 hours, and it must be considered unrealistic to utilize a saliva substitute that has to be taken in such a volume per 24 hours. Thus, the present invention provides an alternative to liquid saliva substitutes, while providing a number of advantageous physical properties discussed below.
[0013] Linseed contains polysaccharides and proteins exhibiting physical properties, which are similar to those of mixed saliva. For patients with reduced saliva production, who comprise the majority of patients with xerostomia, a solid dosage form, for example a tablet, does not at first sight make sense. However, a dry formulation is more convenient because it can be used discreetly, is easily carried and can have slow release characteristics and greater control on the duration of action. It may further provide benefits of higher stability, easier handling, easier transportation and lower manufacturing and packaging costs.
[0014] It has now been found that the process of drying the linseed extract has a surprising effect on the physical properties of the linseed extract. A surprising increase in adsorption to surfaces, especially to tissue, in particular mucosal tissue, is observed. Without wishing to be bound by theory, it is postulated that these changes in physical properties are attributable to changes in the structure of the proteins associated with the linseed extract. Such changes have particular advantages in treatment of xerostomia as an increased adsorption leads to longer residence times on tissue and smaller dosage requirements. Additionally, a resultant solution has improved film-forming properties and gives a much improved mouth feel. This latter advantage is attributed to the solution having a similar viscosity and lubricity to natural saliva.
[0015] As discussed above, it is known that the mixture of proteins and polysaccharides present in linseed extract possess a very unusual combination of rheological and surface-chemical properties, which make them extremely suitable for the application described in the present invention. Prior art teachings suggest that the linseed extract should be applied to the patient in the form of an aqueous composition, effectively a saliva substitute. The present invention teaches quite the contrary. The present invention teaches the administration of a solid composition to the patient. This is contrary to what one would expect when treating patients suffering from xerostomia.
[0016] Such solid preparations provide a convenient metered dose, a discrete packaging and form of administration to the patient and substantially less packaging then an aqueous product.
[0017] A composition of the present invention in solid form is optionally directly administrable to a patient. That is to say that a solid formulation may be used in the treatment, rather than have to be made up into a solution. A composition of the present invention in solid form find particular utility in patients suffering from mild to moderate xerostomia.
[0018] The linseed extract is of the type that is obtainable by a simple extraction in water of said polysaccharides and proteins directly from linseed as described in U.S. Pat. No. 5,260,282, which is incorporated herein by reference. Of course, any extraction method may be employed, for example extraction with an organic solvent alone or with water, a supercritical fluid or a mixture of the above. Where a mixture of an organic solvent and water is used, preferably a protic solvent such as ethanol is utilised.
[0019] One advantage of using a supercritical fluid to extract the polysaccharide and protein fraction from the linseed is that it is extremely easy to remove the solvent from the extract, thus reducing the process steps in order to arrive at a solid product.
[0020] The linseed extract used in the present invention may be obtained by simple dissolution or extraction from linseed in water at ambient temperature, however elevated temperatures and/or pressures may be utilised in the extraction.
[0021] In a particularly preferred embodiment, the extract of the present invention is produced by spray drying or freeze drying solutions, preferably aqueous solutions comprising the linseed extract. Conventional spray drying and freeze drying techniques may be employed. Spray drying and freeze drying techniques have been shown to provide advantageous processing features which have the effect of altering the structure of the proteins associated with the linseed extract. Spray drying is especially preferred as this leads to the most marked change in the physical properties of the linseed extract, for example the adsorption characteristics.
[0022] Preferably, spray drying takes place at a temperature of greater than 110° C., preferably greater than 135° C., more preferably greater than 150° C., most preferably greater than 170° C., for example, about 180° C.
[0023] The adsorption of an aqueous solution, as measured using ellipsometry on a silica substrate, formed by dissolution of the extract or composition according to the invention preferably has an adsorption in the range of from 1.3 to 5 mg/m 2 , more preferably from 1.4 to 4 mg/m 2 , more preferably 1.5-3 mg/m 2 . Where the extract according to the invention has been prepared according to the invention by spray drying, improved adsorption characteristics are obtained and the adsorption is preferably from 1.75 to 2.5 mg/m 2 , more preferably about 2 mg/m 2 .
[0024] In the adsorption measurement method, there is a contact time between when the aqueous solution or dispersion of the extract contacts the silica substrate and when the silica substrate is rinsed wherein the contact time is from 100 to 3000 seconds, preferably from 500 to 2500 seconds, more preferably from 1000 to 2000 seconds.
[0025] Preferably the composition of the present invention is substantially free of water. The composition has preferably less than 10% water by weight of composition, more preferably less than 5% water by weight, more preferably less than 2% water by weight, most preferably less than 1% water by weight.
[0026] A number of additives may be advantageously included in the composition of the present invention.
[0027] In a particularly preferred embodiment a sialogogue is present in the composition according to the invention. Preferred sialogogues include pharmaceutically acceptable organic acids such as citric acid, malic acid, ascorbic acid, fumaric acid and the like. Malic acid is a particularly preferred sialogogue.
[0028] In a particularly preferred embodiment, a lubricious polymer is included in the composition according to the invention. This aids in the disintegration of the composition and in dispersing the composition around the oral cavity. Preferred polymers are selected from alkylene oxide polymers and interpolymers and derivatives thereof where the terminal hydroxyl groups have been modified by esterification, etherification, etc. These are exemplified by the compounds prepared through polymerization of ethylene oxide or propylene oxide and the alkyl and aryl ethers of these polyoxyalkylene polymers. Casein fractions can also provide this function.
[0029] The present invention may also be used to deliver a wide variety of physiologically active compounds and drugs to a patient. As used herein, the term “drug” refers to chemical or biological molecules providing a therapeutic, diagnostic, or prophylactic effect in vivo. The present invention has proved to be particularly useful where it is not possible, or is difficult to produce and maintain a stable aqueous solution incorporating a drug or physiologically active compound. The composition according to the present invention, particularly in solid form, have proved to be more stable, have longer shelf life etc.
[0030] Drugs contemplated for use in the composition according to the invention include the following categories and examples of drugs and alternative forms of these drugs such as alternative salt forms, free acid forms, free base forms, and hydrates:
[0031] Analgesics/antipyretics, for example aspirin, acetaminophen, ibuprofen, naproxen sodium, buprenorphine, propoxyphene hydrochloride, propoxyphene napsylate, meperidine hydrochloride, hydromorphone hydrochloride, morphine, oxycodone, codeine, dihydrocodeine bitartrate, pentazocine, hydrocodone bitartrate, levorphanol, diflunisal, trolamine salicylate, nalbuphine hydrochloride, mefenamic acid, butorphanol, choline salicylate, butalbital, phenyltoloxamine citrate, diphenhydramine citrate, methotrimeprazine, cinnamedrine hydrochloride, and meprobamate;
[0032] Antifungal agents, for example, griseofulvin, ketoconazole, itraconizole, amphotericin B, nystatin, and candicidin;
[0033] Anti-inflammatories, for example, (non-steroidal) indomethacin, ketoprofen, flurbiprofen, naproxen, ibuprofen, ramifenazone, piroxicam, (steroidal) cortisone, dexamethasone, fluazacort, celecoxib, rofecoxib, hydrocortisone, prednisolone, and prednisone;
[0034] Antibacterial agents, for example, amikacin sulfate, aztreonam, chloramphenicol, chloramphenicol palirtate, ciprofloxacin, clindamycin, clindamycin palmitate, clindamycin phosphate, metronidazole, metronidazole hydrochloride, gentamicin sulfate, lincomycin hydrochloride, tobramycin sulfate, vancomycin hydrochloride, polymyxin B sulfate, colistimethate sodium, and colistin sulfate;
[0035] Antiviral agents, for example, interferon alpha, beta or gamma, zidovudine, amantadine hydrochloride, ribavirin, and acyclovir;
[0036] Antimicrobials, for example, cephalosporins such as cefazolin sodium, cephradine, cefaclor, cephapirin sodium, ceftizoxime sodium, cefoperazone sodium, cefotetan disodium, cefuroxime e azotil, cefotaxime sodium, cefadroxil monohydrate, cephalexin, cephalothin sodium, cephalexin hydrochloride monohydrate, cefamandole nafate, cefoxitin sodium, cefonicid sodium, ceforanide, ceftriaxone sodium, ceftazidime, cefadroxil, cephradine, and cefuroxime sodium; penicillins such as ampicillin, amoxicillin, penicillin G benzathine, cyclacillin, ampicillin sodium, penicillin G potassium, penicillin V potassium, piperacillin sodium, oxacillin sodium, bacampicillin hydrochloride, cloxacillin sodium, ticarcillin disodium, azlocillin sodium, carbenicillin indanyl sodium, penicillin G procaine, methicillin sodium, and nafcillin sodium; erythromycins such as erythromycin ethylsuccinate, erythromycin, erythromycin estolate, erythromycin lactobionate, erythromycin stearate, and erythromycin ethylsuccinate; and tetracyclines such as tetracycline hydrochloride, doxycycline hyclate, and minocycline hydrochloride, azithromycin, clarithromycin; and,
[0037] Antiulcer agents, for example, famotidine, cimetidine, and ranitidine hydrochloride.
[0038] A suitable route of administration for the extract and/or the composition according to the invention may, for example, include oral, rectal, transmucosal administration, preferably oral administration.
[0039] An extract of the present invention may be administered to a patient either alone or mixed with suitable carriers or excipient(s) at a dose suitable to treat or ameliorate xerostomia. Such a composition may also contain diluents, fillers, salts, buffers, stabilizers, solubilizers, binders, disintegrators, thickeners and other materials known in the art. The term “pharmaceutically acceptable” means a non-toxic material that does not interfere with the effectiveness of the biological activity of the active ingredient(s).
[0040] A pharmaceutical composition according to the present invention may be formulated in a conventional manner using one or more pharmaceutically acceptable carriers comprising an excipient and auxiliary which facilitates processing of the active component(s) of the composition into a preparation which can be used pharmaceutically. The pharmaceutical composition according to the invention may be manufactured in a manner that is itself known, e.g., by means of a conventional mixing, dissolving, granulating, dragee-making, levigating, emulsifying, encapsulating and/or entrapping process. Most preferably, spray drying or freeze drying are used to prepare a pharmaceutical preparation which may then undergo further processing to produce, for example, a tablet or the like.
[0041] When a therapeutically effective amount of the composition of the present invention is administered orally, the composition will preferably be in the form of a tablet, capsule or powder. For oral administration, the composition according to the invention can be formulated readily by combining the active component(s) with a pharmaceutically acceptable carrier, as is well known in the art. Such a carrier enables the extract of the invention to be formulated as a tablet, pill, dragee, capsule and the like, for oral administration to a patient to be treated.
[0042] A preferred excipient is, in particular, a filler such as a sugar, including lactose, sucrose, mannitol, xylitol, galactitol, isomaltose or sorbitol and mixtures thereof; a cellulose preparation such as, for example, maize starch, wheat starch, rice starch, potato starch, gelatin, gum tragacanth, methyl cellulose, hydroxypropylmethyl-cellulose, sodium carboxymethylcellulose, and/or polyvinylpyrrolidone (PVP). Preferably, a non-cariogenic excipient is used.
[0043] Preferably a disintegrating agent may be added to a composition according to the invention. A suitable disintegrating agent includes a cross-linked polyvinyl pyrrolidone, agar, starch, carboxymethylcellulose, carragenan, carboxymethylcellulose calcium, croscarmellose sodium and/or carboxymethylstarch sodium.
[0044] A dyestuff and/or a pigment may optionally be added to a composition according to the invention to aid identification or to characterise a particular dosage type.
[0045] Optionally a binder is included in the composition according to the invention. A suitable binder includes a crystalline cellulose, sucrose, D-mannitol, dextrin, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, and/or polyvinyl pyrrolidone.
[0046] Optionally a thickener or a viscosity builder is included in the composition according to the present invention. A suitable thickener or viscosity builder is a natural gum, cellulose derivative, and/or acrylic polymer.
[0047] Optionally a solubilizer may be included in the composition according to the invention. A suitable solubilizer is polyethylene glycol, polypropylene glycol, D-mannitol, benzyl benzoate, ethanol, trisaminomethane, cholesterol, triethanolamine, sodium carbonate and/or sodium citrate.
[0048] Optionally a buffer may be included in the composition according to the invention. A suitable buffer includes a phosphate, acetate, carbonate, and/or a citrate buffer solution.
[0049] Optionally a preservative may be included in the composition according to the invention. A suitable preservative includes a p-hydroxybenzoic ester, chlorobutanol, benzyl alcohol, phenethyl alcohol, dehydroacetic acid, and/or sorbic acid. Optionally an antioxidant may be included in the composition according to the invention. A suitable antioxidant is a sulfite and/or ascorbic acid. Where necessary, a further additive such as a preservative, antioxidant, colouring agent, sweetener and the like can be incorporated in the composition according to the invention.
[0050] The composition of the present invention may, if desired, be presented in a pack or dispenser device which may contain one or more unit dosage forms containing the active ingredient. The pack may, for example, comprise metal or plastic foil, such as a blister pack. The pack or dispenser device may be accompanied by instructions for administration.
[0051] A tablet, powder and/or granule may be manufactured by adding an excipient and one or more of a disintegrator, a binder and a lubricant to the extract according to the invention and compression-molding the mixture.
[0052] A composition according to the invention in the form of a quick dissolve tablet may be prepared, for example, by mixing a composition or extract according to the invention with an agent such as a sugar and/or a cellulose derivative, which promote dissolution or disintegration of the resultant tablet after oral administration, usually within 30 seconds.
[0053] A composition according to the invention in the form of a chewable tablet may be prepared by mixing the composition or extract according to the invention with one or more excipients designed to form a relatively soft, flavoured, tablet dosage form that is intended to be chewed rather than swallowed. Conventional tablet machinery and procedures, that is both direct compression and granulation, or slugging, before compression, can be utilized. Those individuals involved in pharmaceutical solid dosage form production are well versed in the processes and the machinery used as the chewable dosage form is a very common dosage form in the pharmaceutical industry.
[0054] A composition according to the invention in the form of a compressed tablet may be prepared by mixing the composition or extract according to the invention with one or more excipients intended to add binding qualities to disintegration qualities. The mixture is either directly compressed or granulated then compressed using methods and machinery well known to those in the industry. The resultant compressed tablet dosage units are then packaged according to market need, for example, as a unit dose, a roll, bulk bottle, or a blister pack.
BRIEF DESCRIPTION OF THE DRAWINGS
[0055] The invention is illustrated with reference to the FIGURE of the accompanying drawings which is not intended to limit the scope of the invention claimed and which shows the adsorption of redissolved linseed extract formulations (10%) on silica. Rinsing was started at 1800 seconds for the mixture.
DETAILED DESCRIPTION OF THE INVENTION
[0056] Materials
[0057] A liquid linseed extract formulation, made in accordance with the process described in U.S. Pat. No. 5,260,282, was used as starting material and was provided by Biosurface Pharma AB.
[0058] Ellipsometry
[0059] Ideally film formation should be measured on a soft tissue such as the inside of a lip. There exists, however, no method that can do this with accuracy. Ellipsometry is very accurate in order to measure surface load, but requires an optically reflecting surface. Silica surfaces, used in the present experiments, have been shown to accumulate salivary material in a way similar to hydroxyapatite, which is the major inorganic component in tooth enamel.
[0060] Ellipsometry is an optical method to measure the changes in polarisation of light upon reflection at a surface (Azzam R M A, Bashara N M, “Ellipsometry and polarised light”, North-Holland Amsterdam, 1977). The instrument used was a Rudolph thin film ellipsometer, type 436 (Rudolph Research, Fairfield, N.J.), equipped with a xenon lamp filtered to 4015 Å. To determine the ellipsometric angles, Δ and ψ for the bare substrate, the position of the intensity minimum was established. From the changes in Δ and ψ, compared to the clean substrate, the thickness and refractive index of a thin film can be calculated according to McCrackin et al. (McCrackin F L, Passaglia E, Stromberg R R, Steinberg H L, J. Res. Nat. Bur. Stand. (1963); A67:363). The adsorbed amount was calculated according to Cuypers et al. (Cuypers P A, Corsel J W, Janssen M P, Kop J M M, Hermens W T, Hemker H C, J. Biol. Chem. (1983); 258:2426) using values for the ratio between molar weight and molar refractivity and for the partial specific volume of 4.1 g/ml and 0.75 ml/g, respectively. Stock solutions were added to milli-Q water, unless otherwise stated, to give 5 ml solution in the ellipsometer cuvette with a protein concentration of 10%. Hydrophilic silica surfaces with an oxide layer of 300 to 350 Å, obtained by thermal oxidation of silicon test slides (p-type, boron doped, resistivity 1-20 Ωcm), were used as substrates.
[0061] The hydrophilic silica surfaces were cleaned according to the following procedure: The surfaces were immersed for 5 min at 80° C. first in NH 4 :H 2 O 2 :H 2 O (1:1:5) (v/v/v) and then in HCl:H 2 O 2 :H 2 O (1:1:5) (v/v/v) with subsequent rinsing in water and after the last step rinsing in ethanol. The cleaned surfaces were stored in ethanol. Immediately prior to use the surface was rinsed in ethanol and water and after drying in the flow of dry nitrogen, plasma cleaned in low pressure residual air, using a radio frequency glow discharge unit (Harrick PDC 3XG, Harrick Scientific Corp., Ossining, N.Y.). As was obvious from their water wettability the surfaces were hydrophilic.
[0062] Spray-Drying
[0063] Linseed extract was spray dried in a conventional spray-dryer. The dimensions of the drying chamber are 0.5×0.15 m 2 . The spray dryer operates co-currently and has a spray-nozzle with an orifice 1 mm in diameter. Inlet gas temperature was 180° C. Outlet gas temperature was kept at 80° C. Liquid feed to the dryer was 5 ml/min. The flow of drying air was 0.8 m 3 /min. Powder was collected in a cyclone at the outlet. Powders were stored at room temperature in closed containers within a desiccator.
[0064] Freeze-Drying
[0065] Freeze-drying was performed in a laboratory freeze-drier Lyovac GT 2 (Steris GmbH, Hurth, Germany). The samples were frozen separately at −80° C. and transferred to the freeze-drier in frozen state. Drying was performed at 0.1 mbar for 70 hours.
EXAMPLES
[0066] Test of Spray Dried and Freeze Dried Linseed Extract Powders:
[0067] Adsorption properties of the aqueous re-dissolved formulations were measured by ellipsometry (as shown in the FIGURE) and compared to the same characteristics of a linseed extract prepared according to the examples of U.S. Pat. No. 5,260,282.
[0068] Therefore, it can be seen that the adsorption behaviour of the linseed extract was affected slightly by freeze drying, whereas the spray-dried product gave a significantly higher adsorbed amount. The adsorption effects observed on the linseed extract of the present invention by drying are quite unexpected. It appears that the protein fraction in linseed extract plays a significant role.
[0069] Furthermore, the film forming properties of the spray-dried product were significantly better than both untreated and freeze-dried linseed extracts, as indicated by higher adsorbed amounts on silica. This unexpected behaviour is likely due to changes in conformation and/or association of proteins and shows that spray drying gives significant advantages. A higher adsorption value is useful because it shows that the linseed extract will have a longer lasting lubricant effect.
[0070] Tablet Formulations of Linseed Extract Powders:
[0071] An example of a tablet composition according to the present invention was prepared by mixing the ingredients presented in Table 1. The tablets are referred to as Salinum tablets. Salinum is the trade name applied to the linseed extract utilised in the present invention.
TABLE 1 Example of composition of Salinum tablets Ingredient Amount (percent w/w) Salinum dry substance 3.3 Isomalt 53.1 Xylitol 37.4 malic acid 4.7 magnesium stearate 1.5
[0072] Typical laboratory batch productions of Salinum tablets were started with dry Salinum powder and grinding it at low temperature in a mortar together with xylitol. This was followed by mixing with isomalt and malic acid in a turbula mixer for 10 minutes, and finally by addition of magnesium stearate including further 2 minutes of turbula mixing. The granulate was then transferred to an eccentric tablet press (Diaf TM-20).
[0073] Salinum protects and lubricates hard and soft surfaces of the oral cavity due to its composition of polysaccharides and proteins. The function of these components is to increase viscosity and provide film formation through surface activity, respectively. An important property of Salinum is its ability to form such films on different types of surfaces, which is important for its effectiveness. This also contributes to the comparatively long duration of residence of Salinum.
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The present invention provides a water-soluble or water-dispersible linseed extract for the treatment of xerostomia characterised in that the extract has an absorption of at least 1.2 g/m 2 , wherein the adsorption is measured by contacting an aqueous solution or dispersion of the extract with a silica substrate, rinsing the silica substrate and then measuring the adsorption by ellipsometry.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of PCT Application No. PCT/EP2003/008336, filed Jul. 29, 2003, which claims priority from German Application No. 102 40 191.8, filed Aug. 28, 2002, which are hereby incorporated herein in its entirety by reference.
BACKGROUND OF THE INVENTION
[0002] The present invention relates to a spunbonded nonwoven made of thermoplastic material. The spunbonded nonwoven has filaments having a filament diameter of less than 2 μm, the filaments being made from bursted fibers.
[0003] A device for producing a nonwoven is known from European Patent Application 0 724 029 B1, in which a Laval nozzle is positioned downstream of a spinning nozzle. The thermoplastic material coming out of the spinning nozzle is drawn through the Laval nozzle using cold air, the air forming a laminar flow. Positioning a spinning nozzle and a Laval nozzle one behind the other is also known from European Patent Application 0 339 240 A2. In this case, however, a hot inert gas is used for cooling and stretching the fibers, the polyphenylene sulfide of the fibers used burst into individual filaments. A device is known from WO 01/00909 A1, which has a spinning nozzle and a Laval nozzle connected downstream. According to WO 01/00909 A1, a pressure difference over the Laval nozzle with simultaneous overpressure in the fiber ensures that the fiber bursts. A plurality of filaments is to result from one fiber.
[0004] The object of the present invention is to expand the technology and fields of application of bursted fibers.
SUMMARY OF THE INVENTION
[0005] The present invention provides a spunbonded nonwoven made of thermoplastic material having filaments, the filaments being made from bursted fibers. The filaments have a length of at least five centimeters, have a filament diameter of less than 1 μm, and are connected to one another at discrete points. The spunbonded nonwoven differs from previously known spunbonded nonwoven is in that it combines various properties of different spunbonded nonwoven methods. It has dimensions which are otherwise only known from meltblown spunbonded nonwovens. In addition, the plurality of fine filaments is produced by another mechanism, which in turn provides freedom in regard to the usable materials. The filaments, which are preferably made by bursting, have a filament diameter of less than 1 μm. For manufacture of the filaments, reference is made to the entire content of WO 01/00909 A1, particularly also in regard to the design of spinning nozzle, Laval nozzle, their dimensions, fluid supplies, and materials used.
[0006] A refinement provides that the filaments are only partially thermally oxidized on their surface, while other regions are not thermally oxidized. Preferably, after leaving a spinning nozzle, the not yet split fibers are kept at a temperature which allows the effect of a thermal and/or chemical oxidation to occur on the fiber surface. In particular, an oxidized layer thickness is generated which is less than 0.15 times the fiber diameter. For this purpose, the spinning speed in particular is appropriately set, as well as the distance of the mouth of the spinning nozzle to the following Laval nozzle. According to a refinement, the thermoplastic material is heated to a temperature above 300° C., particularly in a range between 305° C. and 330° C. The exiting thermoplastic material, which forms the fiber, preferably has a fluid which contains oxygen flowing around it immediately after leaving the spinning nozzle. The fluid preferably has a temperature which lies above the melting temperature of the thermoplastic material.
[0007] Furthermore, the spunbonded nonwoven, which has filaments made of bursted fibers, may additionally have at least one addition. The addition is particularly a corpuscle which does not dissolve in the heated polymer material. Rather, the corpuscle preferably forms a bond with the thermoplastic material. According to a further embodiment, the addition at least partially provides a type of parting plane for the burst of the fibers. The addition preferably has an oblong shape as the corpuscle.
[0008] According to a further embodiment, the filaments at least partially have a corpuscle as an addition which has a diameter between 0.3 and 0.8 times a diameter of a filament. The openings in the spinning plate preferably have a diameter between 1.2 mm and 0.8 mm. Dimensioning of this type allows, for example, additives to be used to which are otherwise not usable due to their behavior, their dimensions, or their other properties. Additions which are approximately as large as the openings are also usable. For example, additions are used which have a magnitude between 0.1 mm and 0.6 mm, particularly a size between a fifth and a half of the opening size.
[0009] According to a further embodiment, the filaments of the spun fiber have super-absorbent polymer (SAP), for example. The SAP is at least partially intercalated in the filaments and is bonded to the thermoplastic material of the filaments. At least approximately 15% to approximately 45% of the filament surface is preferably covered with SAP.
[0010] A refinement provides that the spunbonded nonwoven has an additive, particularly a pigment additive, as an addition. For example, the filaments may have titanium dioxide for pigmentation. Particularly with the use of appropriate opening parameters to generate the fibers, it is possible to achieve stable spinning even if the proportion of the addition is a very high percentage. The addition may preferably make up an approximately 15% to 50% proportion of the fiber. The spunbonded nonwoven preferably has a proportion of addition of at least 10 volume-percent in the filament, preferably between 15% and 35%.
[0011] According to a further exemplary embodiment of the present invention, a spunbonded nonwoven is produced using filaments, the filaments being made from bursted fibers. At least the fibers have at least two different materials. The two materials are preferably selected in such a way that they support burst of the fibers into filaments. In particular, both materials may be supplied to the spinning nozzle while mixed with one another. Another embodiment provides that the two materials are supplied separately from one another and the fibers are subsequently produced from them. For example, the materials are two thermoplastic materials, particularly two different polymers. One of the two materials is preferably a polypropylene, while the other material is a polyethylene. Both materials may also be a polyolefin mixture. A further embodiment provides that the thermoplastic materials have different MFI. One material preferably has an MFI in a range between 15 and 30, the other material has an MFI between 25 and 45 (measured at 230° C.; 2.16 kg).
[0012] A refinement provides that the different materials form different regions of the fiber. For example, the material having a lower melting point forms an inner region of the fiber, while the material having a higher melting point forms an outer region of the fiber. In this way, the filament formation may be controlled. The inner region remains in a quasi-liquid state longer than the outer region. In this way, burst may be controlled in a targeted way. There is also the possibility of positioning the material having the lower melting point in an outer region of the fiber, while the material having the higher melting point lies in an inner region of the fiber. This is particularly preferable if the filaments are to have a surface which is only partially oxidized or influenced by chemical reaction, for example. The external material still reacts with air, for example, while the inner material is already cooled sufficiently that a reaction is avoided during or directly after the burst.
[0013] Besides a core-sheath structure of the fiber, the fiber may also have segments, each having different materials. The segments are preferably at least partially separated from one another and each form filaments. In particular, for example, a spunbonded nonwoven may be produced in this way which has thorough mixing of filaments from at least partially different materials. In this way, different material properties such as different strengths may be combined with one another in one single nonwoven layer.
[0014] A barrier material which has a water column of at least 30 cm is preferably produced using the spunbonded nonwoven layer. The barrier material has a spunbonded nonwoven made of filaments which are made from bursted fibers. In particular, the entire barrier is made only of filaments produced in this way. The barrier preferably has a basic weight of less than 30 gsm with a water column of more than 40 cm at a filament diameter of less than 0.1 μm.
[0015] According to a refinement, the barrier material is an outer layer of a product. In particular, the barrier material has no film. Rather, it may have an additional support structure such as a fabric, a net, or even a further nonwoven. In this way, it is possible to combine a high strength with a high breathing activity of the material, in particular. The barrier material preferably has a spunbonded nonwoven layer made of meltblown thermoplastic material as a support material, onto which the filaments are applied and bonded at discrete locations through the effect of heat and pressure.
[0016] A preferred application of the filament nonwoven is as a building product, which is permeable to water vapor but impermeable to water. The building product preferably has the filaments which are made from bursted fibers as the barrier material. A two-layer or multilayer nonwoven may also be used as a building product, in which, for example, the filaments are embedded between two other nonwoven layers.
[0017] A further preferred application of the filaments is in hygiene products having at least one spunbonded nonwoven layer and a liquid-absorbing core. The spunbonded nonwoven layer forms a barrier for liquid coming out of the core, the barrier being made of filaments which are made from bursted fibers.
[0018] A further application of the filaments is in a hygiene product having at least one spunbonded nonwoven layer as the overlay and a liquid-absorbing core. The spunbonded nonwoven layer is made of filaments which are made from bursted fibers. The filaments are preferably made hydrophilic, through an additional additive, for example.
[0019] Another embodiment of a product provides that a medical product is equipped with at least one spunbonded nonwoven layer, the spunbonded nonwoven layer having filaments which are made from bursted fibers. The filaments form a barrier, which is permeable to air.
[0020] A further application provides using the filaments in a hook and loop fastener system closure system having a hook region and a region in which the hooks catch. The hooks catch in a spunbonded nonwoven made of filaments, the filaments being made from bursted fibers. The filaments are preferably at least 10 cm long and, due to an embossed pattern, produce bulges in which the hooks catch.
[0021] According to a further embodiment, a spunbonded nonwoven layer made of filaments which are made from bursted fibers is used as a filter. The filaments are preferably longer than 5 cm, particularly longer than 10 cm. In this way, one single filament may be connected to its surroundings multiple times and thus secured. Particularly in regions in which high security must be provided, filter materials using these filaments are therefore preferably usable. This may relate to blood filtration and air filtration for highly clean rooms, for example. Furthermore, this filter also has a high strength. It is therefore also particularly suitable as a particle separator in the event of highly active pressure difference. The filaments may particularly be used as an extremely fine filter. At least one prefilter, which holds back the coarse particles, is preferably connected upstream to the extremely fine filter.
[0022] A further application of the filaments relates to the use as a storage medium for liquids and particularly gases. The filaments may also dispense substances or even other agents, for example, fragrance or other things.
[0023] According to a further aspect of the present invention, a method of producing a spunbonded nonwoven from thermoplastic material is provided, the spunbonded nonwoven having filaments and the filaments being made from bursted fibers. The thermoplastic material is heated before spinning to a temperature which at least partially oxidizes the fibers produced on their surface during the subsequent spinning, the fibers only splitting when the temperature inside them is cooled sufficiently that oxidation of the filament is avoided. In this case, reference is made to the entire content of WO 01/00909 A1 in regard to the type of spinning, the filaments and fibers, and particularly in regard to the construction conditions.
[0024] According to a further aspect of the present invention, a method of manufacturing a spunbonded nonwoven from thermoplastic material is provided, the spunbonded nonwoven having filaments and the filaments being made from bursted fibers. The thermoplastic material is heated before the spinning to a temperature such that during the subsequent spinning the fibers produced at least partially oxidize on their surface, heat being supplied to the filaments, after the fibers split into filaments, in such a way that the filaments also at least partially oxidize on their surface.
[0025] The heat is preferably supplied via thermal radiation or convection. For example, the nozzle downstream from the spinning nozzle is heated, so that the air guided through it is heated. In addition, the air emits heat onto the fibers and/or filaments, so that reactions may play out on the fiber and/or filament surface.
[0026] In general, it may also be advantageous to heat the nozzle downstream from the spinning nozzle for other methods of producing filaments by bursting fibers.
[0027] A further idea for manufacturing filaments from bursted fibers provides that the fluid which flows around the fibers does not only stretch the fibers and/or filaments. Rather, this fluid is at least used as a carrier for a substance, so that the substance is bonded to the fiber and/or filament surface. The substance may particularly be deposited on the particular surface.
[0028] An additional idea for manufacturing filaments from bursted fibers provides that the filaments are twisted at least at the start, in the shape of a helix, for example. Twisting of the filaments is produced before depositing, for example, in that the filaments are stretched and/or cooled differently on their surface. This particularly occurs in the moment of the bursting of the fibers. Furthermore, there is the possibility of producing twisting through bicomponent filaments. Twisting may also be performed later, by heating the filaments, for example. Twisted filaments preferably have more than one contact point with neighboring filaments, in particular, two or more filaments are twisted with one another and thus provide additional stability to the nonwoven produced. According to a refinement, the curved filaments are not bonded further to one another. Rather, the only stabilization of the nonwoven is produced by the intersection points of the filaments obtained during manufacture.
[0029] According to an additional idea of the present invention, a spunbonded nonwoven system having a first spinning beam is provided, the first spinning beam being implemented in such a way that fibers produced burst into filaments before being deposited on a movable conveyor belt. The spunbonded nonwoven system has at least one feed for thermoplastic material which forms a laminate with the filaments, the spunbonded nonwoven system having a device for bonding the filaments to the thermoplastic material. The filaments and the thermoplastic material may preferably be bonded through the effect of heat and pressure. The thermoplastic material may also, for example, be applied to the filaments, poured on in at least not yet solidified form, for example, preferably as a film. The bonding of filaments and thermoplastic material into a laminate may be supported using electrostatic charge.
[0030] The laminate may be two-layer or multilayer. The individual layers of the laminate may be bonded to one another in identical or different ways. For example, the layers may be thermobonded, using adhesive means, or may even form the laminate via hydroentanglement, for example. Adhesive means are particularly adhesive fibers, polymers which are heated and form a bond between two layers upon cooling, and, for example, hotmelt adhesives. The application of the adhesive means is preferably performed via spraying or even in the form of a foam application.
[0031] A further embodiment of a spunbonded nonwoven system having a first spinning beam, which is implemented in such a way that fibers produced burst into filaments before being deposited on a movable conveyor belt, provides that the fibers have a fluid flow against them from one side before the fibers enter a nozzle downstream from the spinning nozzle. The flow preferably occurs from a side which is perpendicular to the exit direction of the thermoplastic material from a spinning nozzle. In this way, the fibers may be enveloped by the fluid. This offers the advantage that largely laminar flow is provided from the start and the fluid does not have to be deflected before it flows onto the thermoplastic material.
[0032] According to a further idea of the present invention, a spunbonded nonwoven system having a first spinning beam is provided, the first spinning beam being implemented in such a way that fibers produced burst into filaments before being deposited on a movable conveyor belt. The spunbonded nonwoven system has a heating device in order to heat the fluid streaming around the fibers to a temperature above the melting temperature of a thermoplastic material of the fibers. In this way, complete surface oxidation of the filaments may occur, for example. Also, agglutination of the filaments with one another may be produced in this way. Subsequent further stabilization of the nonwoven produced is preferably dispensed with in this way.
[0033] An additional idea of the present invention, which may also be refined independently thereof, provides a method of generating a film made of thermoplastic material. The thermoplastic material is guided through a slot in order to form a film, the film subsequently being guided through a nozzle in the not yet completely solidified state, a pressure difference over the nozzle acting on the not yet solidified film. Bodies, particularly solid bodies, which are partially exposed through subsequent partial burst of the film, are preferably enclosed in the not yet solidified film.
[0034] Furthermore, a film made of thermoplastic material having enclosed solid bodies is provided, the surface of the film being at least partially bursted. The film is preferably microporous. The microporosity is advantageously achieved in that during burst of the film surface, stretching of the film occurs and/or the thermoplastic material around the solid bodies remains in a quasi-liquid, and therefore movable state, longer than the remaining thermoplastic material. The solid bodies preferably have a higher heat capacity than the thermoplastic material. This principle is also usable for filament formation.
BRIEF DESCRIPTION OF THE DRAWINGS
[0035] Further advantageous embodiment and refinements, as well as features, are illustrated and described in the following drawing.
[0036] FIG. 1 shows a schematic view of a spunbonded nonwoven system;
[0037] FIG. 2 shows a schematic view of a filament;
[0038] FIG. 3 shows a schematic view of a hygiene product;
[0039] FIG. 4 shows a schematic view of a layered product having a barrier material;
[0040] FIG. 5 shows a schematic view of a medical product;
[0041] FIG. 6 shows a schematic view of a film manufacture device; and
[0042] FIG. 7 shows a schematic view of a hook and loop fastener system.
DETAILED DESCRIPTION OF THE INVENTION
[0043] The present inventions now will be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all embodiments of the inventions are shown. Indeed, these inventions may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like numbers refer to like elements throughout.
[0044] FIG. 1 shows a schematic view of a spunbonded nonwoven system 1 . A molten thermoplastic material 3 comes out of a spinning nozzle 2 and forms a fiber 4 . The fiber is surrounded by a fluid stream 5 , which is indicated by arrows. The fluid stream 5 advantageously encloses the fiber 4 directly after the thermoplastic material 3 leaves the spinning nozzle 2 . The fluid stream may be heated using a heater 6 , particularly above a melting temperature of the thermoplastic material. If multiple thermoplastic materials are used to form the fiber 4 , heating may also be performed in such a way that the melting temperature of only one of the thermoplastic materials is exceeded. The fiber 4 enters a nozzle 7 , which is preferably a Laval nozzle. The fluid stream 5 accelerates the fiber 4 , and stretches it at the same time. Simultaneously, due to the acceleration in the nozzle 7 , the pressure is reduced. As the fiber 4 exits and/or while it is inside the nozzle 7 , the fiber 4 bursts, multiple filaments 8 being formed from the single fiber 4 . The filaments 8 are deposited on a movable conveyor belt 9 and form a still unbonded spunbonded nonwoven 10 . A suction device 11 is preferably positioned below the conveyor belt 9 . The suction device 11 continues the fluid stream 5 , so that the filaments 8 may be deposited on the conveyor belt 9 with as little interference as possible. The conveyor belt is preferably positioned at a distance of less than 50 cm to the spinning nozzle 2 . This distance may particularly be varied in order to be able to adjust different product properties. In particular, the distance of the nozzle 7 to the spinning nozzle 2 may also be varied. A prebonded nonwoven, a film, a net, or another material is supplied to the conveyor belt 9 via a first feed 12 for thermoplastic material. This material may be used, for example, as a support structure. A molten thermoplastic material, for example, is applied to the filaments 8 via a second feed 13 , the thermoplastic material forming a film. A device 14 for bonding the filaments 8 to the thermoplastic material is positioned after the second feed.
[0045] FIG. 2 shows a schematic view of a filament 8 which is partially curved. A curvature may particularly be so strongly pronounced that the filament twists and assumes a three-dimensional shape at the same time. In this way, the overall length is reduced and the filament 8 simultaneously occupies a larger volume. Furthermore, it is shown that the filament 8 has corpuscles, for example, additives or other things, which may be located on the surface and also inside the filament 8 .
[0046] FIG. 3 shows a schematic view of a hygiene product 15 having a liquid-permeable top sheet 16 and a liquid-impermeable back sheet 17 . A liquid-absorbing and liquid-storing core 18 is positioned between the top sheet 16 and the back sheet 17 . Preferably, the top sheet and the back sheet have filaments as described above. The filaments of the top sheet are preferably made hydrophilic, while the filaments of the back sheet are preferably made hydrophobic.
[0047] FIG. 4 shows a schematic view of a layered product 19 having a barrier material 20 . The barrier material has filaments as described above. A reinforcement nonwoven 21 is positioned neighboring the barrier material 20 , for example. The barrier material 20 and/or the layered product 19 may be used in different products, for example, in building products, in medical products, in filter applications, in hygiene products, as a storage medium, as a noise absorbing device, in sanitary products, in household products, in packaging, etc.
[0048] FIG. 5 shows a schematic view of a medical product. As indicated here, the medical product is an adhesive bandage 22 , for example. The plaster has filaments 8 as a wound dressing. These are capable of covering the wound with active breathing and simultaneously letting through moisture in vapor form and/or liquid to a storage layer, for example. On the other hand, particles or other things are held back. According to an embodiment which is not shown in greater detail, at least the predominant part of the medical product may also have filaments 8 . Besides the use for adhesive bandages, the filaments may also be used in operating garments, parts thereof, in gloves, protective overalls, covers, etc.
[0049] FIG. 6 shows a schematic view of a film manufacture device having a slot nozzle 23 , from which the molten thermoplastic material exits and forms a film 24 . The film 24 is guided through a neighboring nozzle 25 and stretched by air (not shown in more detail). Due to a pressure difference over the nozzle 25 , the film 24 at least partially bursts on its surface 26 .
[0050] FIG. 7 shows a schematic view of a hook and loop fastener system 27 . The filaments 8 are partially bonded to a carrier 28 and form hooking zones for corresponding hooks 29 of the system 27 .
[0051] Many modifications and other embodiments of the inventions set forth herein will come to mind to one skilled in the art to which these inventions pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the inventions are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.
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This invention relates to a spunbonded nonwoven made of thermoplastic material, which exhibits a filament diameter of less than 1.0 μm. The filaments are made from bursted fibers, whereby the filaments exhibit a length of at least five centimeters and are connected to one another at discrete points.
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BACKGROUND OF THE INVENTION
The present invention relates to agricultural spraying systems, and, in particular, to a modular broadcast/strip application system whereby strip application is achieved with a relatively high back-pressure conversion assembly.
Prior to the present invention, various research and field trials have demonstrated that row crop yields can be increased by applying various liquid fertilizers which may include various proportions of nitrogen, phosphorous and potassium in concentrated bands or strips relative to the row crops rather than by applying the same amount of material in a broadcast fashion over the entire area between row crops. While strip application may be performed prior to, during, or subsequent to planting and with various desired spacings relative to the row crops, it generally serves to make the applied treatment materials more rapidly available to the growing row crops. The availability of nutrients and increased yields, in turn, have however become more important as the costs for such treatment materials have risen. For more information with respect to such application techniques, attention is directed to Chapter 20 of the Liquid Fertilizer Manual of the National Fertilizer Solutions Association and to various product literature from the various suppliers of chemicals for row crops (e.g. a publication entitled Improving Per Pound Efficiency by Positive Placement published by Allied Chemical Company).
While surface band and strip application techniques have been known for some time, application systems are more typically designed for broadcast spraying and which is the more forgiving of operator and equipment error. Single purpose systems have been designed though for strip application. In either case, the resulting special purpose systems require an operator to maintain separate pieces of equipment which is not economical.
The present invention, therefore, is directed to a multi-purpose spray system and in particular to a broadcast spray system that is easily converted to a strip spray system via the coupling of individual strip spray nozzle assemblies to desired ones of the outlet parts of the broadcast system. In this regard, the spray nozzles of a broadcast spray system are typically spaced apart from one another on the order of 60 inches. For strip application, however, it is desirable to space the nozzles on the order of 15, 20 or 30 inches apart. Assuming therefore that it is desired to apply the same amount of material with more nozzles, the flow rate per nozzle must be reduced on the order of one-fourth, one-third or one-half for the above outlet port spacing. While this end can be achieved by reducing the aperture size of the orifice for each nozzle, such a reduction introduces problems that are not advantageous to a convertible system.
In particular, attendant with any decrease in the aperture size of the orifices for strip application are concerns with respect to pressure and particulate size, since often times the liquids that are sprayed are comprised of mixtures that contain suspended solids. Therefore too small an aperture can result in blockage, should various of the suspended particles become lodged at the orifice opening. The present invention, therefore seeks to minimize clogging sensitivity by using relatively large orifices having apertures on the order of 0.20 inches in diameter for strip application. Such orifices however introduce concerns with respect to pressure.
Pressure is a concern in that the pressure requirements of a broadcast system require less regulation than for a strip system. Specifically, due to the fewer number of nozzles for a broadcast system, a single control can typically maintain equivalent pressures at each outlet port and nozzle and thereby achieve a uniform flow rate at each nozzle. However, by converting a broadcast system to a strip system by increasing the number of nozzles and at the same time increasing the aperture size and reducing the pressure at each nozzle, variations in pressure from nozzle to nozzle can result and produce disparities in flow rates, which otherwise are not encountered at the higher pressures and fewer nozzles of a broadcast system. Therefore it is a primary object of the present invention to enable the conversion of a broadcast system to a strip application system having substantially uniform pressures at each strip nozzle and wherein the system will accommodate various types of liquid suspension as well as totally dissolved solutions.
It is a further object of the present invention to enable a modular system capable of high speed application with output metering orifices that also shape the flow streams at each nozzle into narrow-high velocity solid streams.
It is another object of the present invention to minimize or eliminate the sensitivity to viscosity variations in mixed fertilizers and maintain a predictable flow rate.
It is a still further object of the present invention to enable a convertible system wherein the flow rate at each outlet nozzle is regulated by a plurality of pressure adjusting series/parallel orifices.
These objects and still others will, however, become more apparent upon a reading of the following description with respect to the following drawings.
SUMMARY OF THE INVENTION
A pressure regulating strip nozzle assembly detachably mountable to a broadcast liquid spray system for ensuring uniform strip application of liquid treatment materials via each outlet nozzle of the assembly. The assembly essentially comprises a secondary metering nozzle detachably mountable to a primary distribution manifold, a secondary distribution manifold coupled to the secondary metering nozzle and a plurality of secondary nozzles coupled thereto for applying liquids or liquid suspensions in relatively solid streams.
In one embodiment, each of the nozzles of the assembly utilize sharp edged orifices that are relatively insensitive to viscosity changes so that flow rate is primarily determined by pressure alone. They are, in turn, sized to be relatively clog-free when used with liquid fertilizers containing suspended solids. A desired back-pressure at each outlet nozzle is further achieved via a series/parallel assembly configuration, although various other desired configurations may be employed.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a perspective view of a generalized system diagram of a modular broadcast/strip liquid spray system employing the present invention.
FIG. 2 shows a perspective view of the present strip conversion assembly.
FIG. 3, comprised of FIGS. 3a, 3b and 3c, shows a typical control arrangement and various alternative arrangements.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1, a system diagram, is shown of a convertible braodcast/strip spray system including the present invention. Such a system typically comprises a liquid storage tank 2 that is loaded with desired liquid and dry treatment materials, an eductor assembly 4 and a supply line 6. The liquid treatment materials (i.e. fertilizers, insecticides, herbicides, etc.) are then applied via a pressurized system of conduits, valves and a pump to a primary manifold assembly and whereupon a plurality of spaced apart nozzles are mounted so as to cause the liquid matter to be broadcast applied to the row crops.
In particular, the liquid is distributed to a high pressure pump 14 via the gravity feeding thereof from the tank 2 to a suction line 8, a normally open shut-off valve 10 and a normally closed reload valve 12. The liquid material is then pumped via the pump 14 and a high pressure conduit 16 to a diverter junction near the normally closed load valve 18. At the diverter junction, the liquid material is able to flow in either of two conduits, that is, to the primary manifold 20 or to the sparger conduit 22.
The particular amount of material that flows to each of the conduits is controlled via a flow and pressure regulating primary manifold supply valve 24 and a flow regulating sparger valve 26 that are respectively placed therealong. Depending upon the pressure on the liquid material as it passes through the conduits at these valves, and which pressure is operator monitored, the operator may open and close the valves 24 and 26 in desired amounts to vary the pressure and amount of material passing therethrough. Such pressure regulation is achieved via the vernier pressure throttling controls 28 and a lever controlled sparger valve 30. Typically though, the sparger valve 26, is relatively coarsely adjusted so as to be partially open, whereas the primary manifold supply valve 24 is monitored via a pump pressure gauge 31 and a nozzle pressure gauge 33 and regulated via the throttling controls 28 so as to control the pressure of the liquid in the primary manifold 20.
Referring to the liquid paths, a portion of the high pressure liquid at the diverter junction, is returned to the tank 2, via the sparger conduit 22 and the sparger control valve 26, which reduces the pressure prior to the liquid entering the storage tank 2. At the tank 2, the liquid is then returned via a plurality of openings formed within the sparger conduit 22 and which openings produce a continual agitation of the liquid in the tank 2, and whereby a uniform suspension is maintained.
The remaining liquid is diverted via the primary control valve 24 at the desired operating pressure to a bifurcated primary manifold supply line 32 that, in turn, supplies the various halves 20a and 20b of the primary manifold or spray boom 20 through filter 35 and remotely controlled shut-off valves 34. The shut-off valves 34 are placed intermediate the halves of the primary manifold 20 and permit the operator to manually shut off one or the other of the halves 20a and 20b of the spray boom 20. It is to be recognized too that while the system of FIG. 1 contemplates a two section spray boom, either more sections or a single section spray boom may be employed.
The feature of note though is that such a spray boom 20 acts as a primary manifold to deliver the treatment material to a plurality of outlet ports 36 that are spaced apart from one another along the boom 20. Such ports 36 for a broadcast application system are typically designed to be compatible with a broadcast nozzle 37 so as to cause the distribution of the liquid in an overlapping spray pattern and ensure 100% coverage of the area sprayed with an approximate uniformity of distribution from end to end of the boom 20. The spacing between such nozzles for a broadcast application system, being typically on the order of 60 inches. Alternatively, for a strip application system, the outlet ports 36 are spaced closer together and the associated nozzles are designed so as to eject the liquid in streams, rather than in a spray.
While individual broadcast and strip application systems have previously been employed, the present invention contemplates a modular system that in a simplistic fashion permits the conversion of the higher pressure broadcast spray system to a low pressure strip application system. Such a conversion assembly is illustrated in FIG. 1 via the alternative strip nozzle assemblies 40 that are shown relative to the various outlet ports 36. The assemblies 40 eject narrow streams of liquid and which streams are typically directed in a relative spacial orientation to the row crops (i.e. a specific distance to the right or left thereof or immediately thereover). The strip assemblies 40, also, like the broadcast nozzles 37, are detachably mounted to the outlet ports 36 via self-aligning couplers (not shown) containing various mating keys, slots and cam-locks. The self-aligning couplers, however, are the subject of my co-pending application entitled "Self-Aligning Coupler for Fluid Transmitting Conduits" Ser. No. 411,633, filed Aug. 26, 1982, now abandoned, and for more information, attention is directed thereto. It is also to be noted that the present strip application assembly is adaptable to the modularly engineered equipment of the present assignee, for example the Ag-Chem TERRA-GATOR®1603 field applicator.
Referring now to FIG. 2, a detailed perspective view is shown of an individual strip application assembly 40. In particular, each assembly is comprised of a secondary manifold 50 and which in a 1×2 configuration contains a secondary supply metering orifice assembly 52 and two strip nozzles 54. Thus, the liquid is supplied from an outlet port 36 to the secondary orifice assembly 52, to the manifold 50 and thence to the individual strip nozzles 54. It is to be recognized though that depending upon the system, any number of strip nozzles may be coupled to the strip manifold 50, but for most applications and a typical 60 inch broadcast distribution system, either a 1×2 or a 1×3 configuration is sufficient and will accommodate 30 and 20 inch spacings.
From FIG. 2, it is to be noted that each strip nozzle 54 is individually comprised of a threaded body 56, a sharp edged orifice 58 and a cap 60. The body 56 is typically formed from non-corrosive stainless steel or nylon and is comprised of two threaded segments (e.g. 3/8 inch NPT) which are threadably contained within an appropriate female, elbow fitting 62 on the manifold 50. The orifice 58, in turn, is typically fabricated from stainless steel as a flat washer with a thickness in the range from 0.050 to 0.070 inches and a precision aperture 59 on the order of 0.200 or 0.250 inches in diameter. While various shapes or sizes of apertures may be formed, for the present embodiment a circular straight walled apparatus 59 is preferred and which produces the desired outlet flow stream and insensitivity to viscosity changes. Furthermore, an aperture of 0.20 inches has been emperically determined to be most compatible with the spray system's 10 to 60 psi pressure range, required flow rate, and resistance to clogging by suspension fertilizers. Finally the cap 60 comprises a female threaded, nylon fitting which has an opening formed in the outlet end so as to circumscribe the aperture 59 of the orifice 58. It should be noted too that typically the strip manifold 50, elbows 62 and "T" fittings 64 are manufactured from a PVC material in that such a material is extremely rugged, light and non-corrosive in fertilizer mixes.
The primary orifice assembly 52 on the other hand is substantially the same as the strip nozzle assembly 54, although its body is formed so as to contain the requisite keys and shoulders so as to facilitate its detachable coupling with the couplers 38 at the outlet ports 36. The body 66 thereof is, in turn, coupled to the T fittings 64 by a threaded nipple 68 and intermediate the coupler 38 and body 66 is a secondary orifice 68 and gasket 70. The secondary supply or metering orifice 68 in the preferred embodiment is interchangeable with outlet orifice 58, except it may be size matched with a different aperture dimension. It should be recognized though that while in the present system configuration a sharp edged orifice is desired, in various other configurations, various other aperture shapes and/or tapered edges or edges of complex shapes may be preferred, especially where such shapes produce the desired flow and back-pressures when used with non-viscous fluids.
Before continuing, it should be noted too that while the nozzles of the strip assemblies 40 of FIGS. 1 and 2 are shown generally in 90° configurations, various other angulated configurations or fitting placements along the strip manifold 50 may be desired depending upon the configuration of the equipment and spray boom 20. In particular, it may be desired to offset the strip manifold 50 from the boom 20 at a different angle and which can be achieved via various angulated couplers (i.e. 30°, 45° etc.). Alternatively, the placement of the T fitting and or strip nozzles 54 may be altered by cutting the lengths of manifold pipe as desired and/or using various other angulated fittings to accommodate the system configuration.
Referring again to FIG. 1, it should be noted that the present strip application system is essentially configured in a series/parallel fashion in that while each of the spaced apart outlet ports 36 on the spray boom 20 are supplied from the tank 2, each of the strip nozzles 54 are supplied in parallel from the series coupled primary nozzle 52 at each individual outlet 36. Such an arrangement is of particular merit for modular systems of the present type in that this configuration in combination with the straight edged orifices 58 and 68 produces a sufficient back-pressure so as to accommodate the pressure range of the spray system. Also, as mentioned at the low end of the pressure range, it is of particular importance to maintain a constant pressure, since any variations at the low end of the range result in greater disparities in flow rate than at the higher end of the pressure range. Thus, it is necessary when reconfiguring a broadcast system to a strip system that a sufficient amount of back-pressure (within the range of the primary supply valve 24) be maintained at the strip nozzles.
It is also to be recognized that, whereas here, it is desired to use an orifice or metering disc 58 with as large an aperture 59 as possible as as to make the system insensitive to clogging from intentionally suspended solids in the mixture, it becomes very difficult to maintain a sufficiently large back-pressure. Further, where it is desired, as here, to obtain a flow rate range on the order of 10:1 (e.g. 100 to 10 gallons per acre) within a low and relatively narrow pressure range (i.e. 10 psi to 60 psi), this end becomes even more difficult. Attention is therefore directed to FIG. 3, wherein FIG. 3a shows a conventional broadcast system with orifices 58 only at the nozzles and where FIGS. 3b and 3c show alternative conversion systems.
Hypothetically and referring to FIG. 3b, while the back-pressure of a converted system may be increased to each strip nozzle 54 on a boom 50 that contains a number of such nozzles 54 by inserting a number of orifices 58 in series with each strip nozzle 54 (since the back-pressure at each series orifice is additive), such an arrangement would require an excessive number of orifices per nozzle.
For example, assuming a spacing of 30 inches between row crops, the flow rate required for 15 gallon per acre distribution and a distribution speed of 15 miles per hour is:
Q=RVW/5940
where:
R=distribution per acre
V=velocity
W=spacing between crops
or for the present assumptions ##EQU1##
The pressure necessary to supply this flow rate at each nozzle, in turn, is: ##EQU2## where:
S=1.0 specific gravity
q=1.136 gallons/minute Cd=0.65 for sharp edged orifice
d=0.20
or, ##EQU3##
Thus and as per the above assumptions, an aperture 59 of 0.20 inches in diameter produces a flow rate of 1.136 gallons per minute and requires a nozzle pressure of 2.15 psi. Consequently, for a broadcast system, such as here, operating in a pressure range from 10 to 60 psi, it would require five of such orifices per nozzle to achieve a controllable pressure (i.e. 5 orifices×2.15 psi=10.7 psi), and which clearly is not cost effective or practical.
However, by applying a basic hydraulic principle of flowthrough orifices (i.e. the pressure is proportional to the square of the flow) and using a secondary supply orifice 68 in the primary orifice assembly 52 in the fashion of FIGS. 2 and 3c it can be seen that the back-pressure induced by a secondry orifice 68 of a diameter of 0.20 inches is equal to 4×2.15 or 8.6 psi. This then when added to the parallel strip nozzle pressure of 2.15 psi results in the same back-pressure of 10.75 psi. Thus, the series/parallel system of FIG. 3c requires only three orifices per outlet port 36 to meet system pressure requirements and is therefore more desirable than the series system of FIG. 3b. It should be noted too that while a series/parallel combination of two or three strip nozzles per secondary supply nozzle 52 is preferrable for most applications, still other configurations can be employed. Further, it is to be recognized that the present organization permits the use of various flow shaping and secondary supply orifices 68 with each strip nozzle assembly so as to produce various other back pressures and stream shapes.
While the present invention has been described with respect to various particular embodiments thereof, it is to be recognized that still other equivalent structures may suggest themselves to one of skill in the art. It is therefore contemplated that the present invention should include all of such equivalents within the spirit and scope of the above described invention and the following claims.
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A strip nozzle assembly containing a detachable, pressure regulating inlet coupler and a plurality of pressure regulating outlet nozzles, whereby agricultural sprays may be strip applied. The assembly having particular application in a modular spraying system adaptable to either broadcast or strip spraying. Compatibility with system pressure and desired flow rates are achieved via flat plate, sharped edge orifices that in one embodiment are arranged in a series/parallel configuration.
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CROSS-REFERENCE TO RELATED APPLICATION
This application expressly claims the benefit of earlier filing date and right of priority from the following co-pending patent applications: U.S. Provisional Application U.S. Serial No. 60/086,937, entitled “Contaminant Tolerant Compressed Natural Gas Injector” filed May 27, 1998; and U.S. Provisional Application U.S. Serial No. 60/086,939, entitled “Needle Valve For Low Noise Fuel Injector” filed May 27, 1998. Both cited provisional patent applications are expressly incorporated in their entirety by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present application relates to a compressed natural gas injector, which is tolerant of contamination in the gas.
2. Description of the Related Art
Compressed natural gas (hereinafter sometimes referred to as “CNG”) is becoming a common automotive fuel for commercial fleet vehicles and residential customers. In vehicles, the CNG is delivered to the engine in precise amounts through gas injectors, hereinafter referred to as “CNG injectors”. The CNG injector is required to deliver a precise amount of fuel per injection pulse and maintain this accuracy over the life of the injector. In order to maintain this level of performance for a CNG injector, certain strategies are required to help reduce the effects of contaminants in the fuel.
Compressed natural gas is delivered throughout the country in a pipeline system and is mainly used for commercial and residential heating. While the heating systems can tolerate varying levels of quality and contaminants in the CNG, the tolerance levels in automotive gas injectors are significantly lower.
These contaminants, which have been acceptable for many years in CNG used for heating, affect the performance of the injectors to varying levels and will need to be considered in future CNG injector designs. Some of the contaminants found in CNG are small solid particles, water, and compressor oil. Each of these contaminants needs to be addressed in the injector design for the performance to be maintained over the life of the injector.
The contaminants can enter the pipeline from several sources. Repair, maintenance and new construction to the pipeline system can introduce many foreign particles into the fuel. Water, dust, humidity and dirt can be introduced in small quantities with ease during any of these operations. Oxides of many of the metal types found in the pipeline can also be introduced into the system. In addition, faulty compressors can introduce vaporized compressor oils, which blow by the seals of the compressor and enter into the gas. Even refueling can force contaminants on either of the refueling fittings into the storage cylinder. Many of these contaminants are likely to reach vital fuel system components and alter the performance characteristics over the life of the vehicle.
In general, fuel injectors require extremely tight tolerances on many of the internal components to accurately meter the fuel. For CNG injectors to remain contaminant tolerant, the guide and impact surfaces for the armature needle assembly require certain specifically unique characteristics. We have invented a CNG fuel injector which represents a significant improvement over presently known injectors while being tolerant to contaminants commonly found in compressed natural gas. We have also invented a method of directing compressed natural gaseous fuel through such injectors in a manner to promote efficient and effective firing without misfire.
SUMMARY OF THE INVENTION
The invention relates to an electromagnetically operable fuel injector for a gaseous fuel injection system of an internal combustion engine, the injector having a generally longitudinal axis, which comprises a ferromagnetic core, a magnetic coil at least partially surrounding the ferromagnetic core, an armature magnetically coupled to the magnetic coil and being movably responsive to the magnetic coil, the armature actuating a valve closing element which interacts with a fixed valve seat of a fuel valve and being movable away from the fixed valve seat when the magnetic coil is excited. The armature has a generally elongated shape and a generally central opening for axial reception and passage of gaseous fuel from a fuel inlet connector positioned adjacent thereto. The fuel inlet connector and the armature being adapted to permit a first flow path of gaseous fuel between the armature and the magnetic coil and a valve body shell as part of a path leading to the fuel valve. At least one first fuel flow aperture extends through a wall portion of the armature to define a second flow path of gaseous fuel as part of a path leading to the fuel valve.
In the preferred embodiment, the armature defines at least one-second aperture in a wall portion thereof to define a third flow path of gaseous fuel as part of a path leading to the fuel valve. The at least one second aperture is oriented at a generally acute angle with respect to the longitudinal axis. Further, the fuel inlet connector and the armature are a spaced to define a working gap therebetween and are adapted to permit the first flow path of gaseous fuel within the working gap. The fuel injector further comprises a valve body positioned downstream of the armature and having at least one aperture in a wall portion thereof for reception of fuel from at least two of the flow paths of gaseous fuel from the armature and the fuel inlet connector.
Further, a valve body shell at least partially surrounds the armature and the valve body, the valve body shell defining a radial space with the armature for passage of the first flow path of gaseous fuel between the armature and the valve body shell. The fuel inlet connector is positioned above the armature and is spaced from the armature by a working gap, the fuel inlet connector defining a through passage for directing fuel toward the armature and the fixed valve seat.
The fuel inlet connector comprises an upper end portion adapted for reception of gaseous fuel from a fuel source, and a lower end portion for discharging gaseous fuel, the lower end portion having a lower surface which faces an upper surface of the armature, the lower surface of the fuel inlet connector having a plurality of radially extending raised pads defined thereon, the pads having recessed portions therebetween to permit fuel to flow therethrough and across the working gap defined between the fuel inlet connector and the armature.
The armature defines at least one first and at least one second fuel flow aperture extending through wall portions thereof, the at least one first and at least one second aperture oriented at an acute angle with the longitudinal axis, and positioned for directing fuel therethrough toward the fixed valve seat. The lowermost surface of the fuel inlet connector and the armature are adapted to permit gaseous fuel to flow across the working gap and between the armature and the magnetic coil whereby at least three fuel flow paths are permitted. Preferably lowermost end portion of the fuel inlet connector has a generally chamfered configuration along the lowermost outer surface thereof. The generally chamfered portion of the fuel inlet connector preferably has a generally arcuate cross-section.
The valve-closing element is a valve needle adapted for selective engagement and disengagement with the fixed valve seat and is attached to the armature by crimped portions of the armature. A fuel filter is positioned at an upper end portion of the fuel inlet connector for filtering fuel prior to reception by the fuel inlet connector. The fuel inlet connector includes a lower surface portion having a plurality of radially extending grooves defining a corresponding plurality of radially extending raised pads so as to reduce the effective surface area of the lower surface portion of the fuel inlet connector facing the armature to thereby permit the gaseous fuel to flow generally transversely in the working gap, the transverse fuel flow thereby preventing accumulation of contaminants in the working gap. The generally radially extending pads preferably have a generally trapezoidal shape, but may be of various shapes, depending upon the circumstances or results desired. Further, the fuel injector is applicable to liquid fuel systems such as gasoline, as well as with the preferred CNG systems.
The valve closing element is a generally elongated valve needle having a spherically shaped end portion and configured and adapted to engage a frust-conically shaped fixed valve seat to close the valve, and movable therefrom to open the valve to permit fuel to pass therethrough toward the intake manifold of the internal combination engine. The valve needle is connected to the lower end portion of the armature by crimped portions. The resilient device to move the armature to close the valve is a coil spring in engagement at one end with the fuel inlet connector and at the other end with the armature to bias the armature downwardly toward the valve seat. The armature includes at least two of the first apertures extending through wall portions thereof and generally transverse to the longitudinal axis for receiving fuel from the generally axial elongated central opening. The armature may alternatively define a plurality of the first apertures for receiving fuel from said generally axial elongated central opening. The armature may also define a plurality of the second apertures, at least certain of the second apertures extending at a generally acute angle to the longitudinal axis to receive fuel from the generally central opening.
A method is disclosed for directing gaseous fuel through an electromagnetically operable fuel injector for a fuel system of an internal combustion engine, the injector having a generally longitudinal axis, and including a fuel inlet end portion and a fuel outlet end portion, a fuel inlet connector positioned at the fuel inlet end portion and having a fuel inlet end portion and a fuel outlet end portion, an armature positioned adjacent the fuel outlet end portion of the fuel inlet connector and having a generally central elongated opening for reception of fuel from said fuel inlet connector, the armature being spaced from the fuel inlet connector to define a working gap to permit movement of the armature toward and away from the fuel inlet connector to selectively open and close a fuel valve to permit gaseous fuel to pass therethrough to an air intake manifold. The method comprises, directing the gaseous fuel to pass axially through the fuel inlet connector, directing the gaseous fuel to pass from the fuel inlet connector to the generally elongated central opening of the armature in an axial direction toward the fuel valve, directing at least a portion of the fuel flow from the fuel inlet connector to the armature to flow generally transversely across the working gap, and diverting at least a portion of the flow of gaseous fuel passing through the armature to flow in a direction away from the axial direction. The step of directing the gaseous fuel passing through the armature to flow in a direction away from the axial direction is preferably accomplished by directing the gaseous fuel through at least one first aperture provided in a wall portion of the armature. Preferably the at least one first aperture in the wall portion of the armature extends generally transverse to the axial direction. A lower end portion of the fuel inlet connector preferably faces an upper end portion of the armature and is configured to permit the gaseous fuel to flow from the fuel inlet connector to be directed transversely across the working gap. Preferably at least a portion of the gaseous fuel flowing in the armature is permitted to pass through at least one second aperture in a lower wall portion thereof, the at least one second aperture extending at an acute angle to the longitudinal axis, whereby at least three separate fuel flow paths are established. The injector preferably comprises a magnetic coil system and said armature is magnetically coupled to the magnetic coil system to cause the armature to move toward and away from the fuel inlet connector. At least one of the fuel flow paths is located between the armature and the magnetic coil of the magnetic coil system, as well as between the armature and a valve body shell at least partially surrounding the armature. The at least one first and second apertures in the armature are preferably from about 1 to about 2.0 mm in diameter. Further, predetermined numbers of the first and second apertures are provided and the diameters thereof are predetermined to establish a predetermined number of fuel flow paths and volumetric flow rates thereof.
BRIEF DESCRIPTION OF THE DRAWINGS
Preferred embodiments of the invention are described hereinbelow with reference to the drawings wherein:
FIG. 1 is an elevational view, partially in cross-section, of a preferred embodiment of a compressed natural gas injector constructed according to the invention;
FIG. 2 is an enlarged elevational cross-sectional view of the lower portion of the injector of FIG. 1, showing the improved armature and needle which forms part of the invention;
FIG. 3 is a partial elevational cross-sectional view of the lower end portion of the fuel inlet connector of the injector shown in FIG. 1;
FIG. 4 is a plan view of the bottom surface of the preferred fuel inlet connector shown in FIG. 1;
FIG. 5 is an elevational cross-sectional view of a preferred embodiment of the armature shown in FIG. 1 and illustrating the improved fuel flow paths resulting therefrom;
FIG. 6 is an elevational cross-sectional view of the upper portion of a preferred embodiment of the valve body shown in FIG. 1;
FIG. 7 is a partial elevational cross-sectional view of the lower end portion of an alternative embodiment of the fuel inlet connector shown in FIG. 3;
FIG. 8 is a plan view of the bottom surface of the fuel inlet connector shown in FIG. 7;
FIG. 9 is an elevational cross-sectional view of an alternative embodiment of the armature shown in FIG. 5;
FIG. 10 is an elevational cross-sectional view of the upper portion of an alternative embodiment of the valve body shown in FIG. 6;
FIG. 11 is an enlarged elevational view of the armature shown in FIG. 5 and a cross-sectional view of the valve body shown in FIG. 6, incorporating an improved valve needle a fuel columnating jet flow device;
FIG. 12 is an enlarged elevational view, partially in cross-section, of the armature shown in FIG. 5, and the improved valve needle shown in FIG. 11;
FIG. 13 is an enlarged cross-sectional view illustrating the sealing tip portion of the valve needle as seated on the fixed valve seat as shown in FIGS. 1 and 11, illustrating the preferred dimensional relationship between the needle tip, the fixed valve seat and the lower needle guide; and
FIG. 14 is a view taken along lines 14 — 14 of FIG. 11, illustrating a preferred valve needle lower guide having arcuately shaped fuel passage openings.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring initially to FIG. 1 there is shown a CNG injector 10 which is constructed according to the present invention. Injectors of the type contemplated herein are described in commonly assigned U.S. Pat. No. 5,494,224, the disclosure of which is incorporated by reference herein.
The injector 10 includes housing 12 containing armature 14 to which valve needle 16 is attached by crimping as will be described later in conjunction with FIG. 12 . Fuel inlet connector 18 includes central fuel flow opening 13 and CNG filter 20 at the upper end portion of opening 19 as shown. The fuel inlet connector 18 also includes adjusting tube 22 connected thereto at 24 by a known crimping procedure. Housing 12 includes inner non-magnetic shell 26 which surrounds the inlet connector 18 and armature 14 having central fuel flow opening 11 as shown. Armature 14 and inlet connector 18 define with housing 12 , an enclosure for coil 28 which is selectively energized to move armature 14 and needle 16 upwardly to open the valve aperture 41 , and selectively deenergized to permit armature 14 and needle 16 to return to the “closed valve” position as shown, under the force of coil spring 30 . Fuel flow into the injector begins at filter 20 and passes through fuel inlet connector 18 , to armature 14 , and ultimately to valve aperture 41 of valve seat 40 into the intake manifold of the engine (not shown).
Referring further to FIG. 1 in conjunction with FIG. 2, valve body shell 32 , which is made of a ferromagnetic material and which forms part of a magnetic circuit, surrounds valve body 34 and has at the upper end, upper guide 36 as shown. Space 36 a between upper guide 36 and armature 14 is about 0.010 to about 0.015 mm on the diameter, and permits guiding movement of armature 14 . Lower O-rings 38 provide sealing between the injector 10 and the engine intake manifold (not shown) and upper O-rings 40 provide sealing between the injector 10 and the fuel rail (also not shown). Valve body 34 defines central fuel flow opening 35 .
In FIG. 2, valve body shell 32 is attached to valve body 34 , preferably by weld 32 a , and at the upper end by weld 26 a , to non-magnetic shell 26 . Non-magnetic shell 26 is in turn welded to fuel inlet connector at 26 b . Thus, fuel flowing from fuel inlet connector 18 across working gap 15 must flow through the clearance space 14 a between armature 14 and valve body shell 32 which is also provided to permit upward and downward movement of armature 14 . The space 14 a is approximately 0.10 to 0.30 mm on the diameter.
Referring again to FIGS. 1 and 2, valve seat 40 contains a valve orifice 41 and a funnel shaped needle rest 42 having a frusto-conical cross-sectional shape. The valve seat 40 is maintained in position by back-up washer 44 and sealed against fuel leakage with valve body 34 by O-ring 46 . Overmold 48 of suitable plastic material such as nylon supports terminal 50 which extends into coil 28 and is connected via connection 51 to provide selective energization of the coil to open the valve by raising the armature 14 and valve needle 16 against the force of spring 30 . Coil 28 is surrounded by dielectric plastic material 53 as shown in the FIGS.
In injectors of this type, the interface space 15 (or working gap 15 ) between the inlet connector and the armature is extremely small, i.e. in the order of about 0.3 mm (millimeters), and functions relatively satisfactorily with conventional fuels which are relatively free of contaminants such as water, solids, oil, or the like, particularly after passing through a suitable fuel filter. Accordingly, when the two surfaces surrounding space 15 are in such intimate contact that the atmosphere between them is actually displaced in relatively significant amounts, atmospheric pressures acting on the two members actually force the two surfaces together. Any liquid contaminant present at the armature/inlet connector interface would allow for the atmosphere to be displaced, thereby adversely affecting the full and free operation of the armature/needle combination.
When known injectors, which functioned at relatively acceptable levels with relatively clean conventional fuels, were utilized with CNG, impurities such as oil or water at the inlet connector/armature interface produced a force of about 16.5 Newtons holding the armature to the inlet connector. In comparison, the force provided by spring 30 is in the order of about 3 Newtons, thus fully explaining the erratic closing of the armature/valve needle when the fuel utilized with known injectors is CNG. In particular, the 16.5 Newton force holding the inlet connector and armature together is due to the fact that the fuel operating pressure within the injector is about 8 bar (i.e. 8 atmospheres) and this force of about 16.5 Newtons acts across the lower surface area of the inlet connector 18 , which is about 21 square millimeters (i.e. mm 2 ). Thus a relatively minor slick of oil or other impurity within space 15 of a known injector will cause the inlet connector and the armature to become temporarily attached to each other, particularly due to the 8 bar pressure acting on the remaining surfaces of the inlet connector and armature. As noted, the tendency for the armature to become attached to the inlet connector results in erratic valve closing.
Significant features of the present invention are provided inter alia, to eliminate the aforementioned erratic valve closing and improve the operation of the injector. In FIG. 3, the lower end portion of inlet connector 18 is configured as shown by the arcuately chamfered end 52 . This configuration provides a beneficial effect in that it directs and orients the magnetic field across the working gap 15 in a manner which optimizes the useful magnetic force created for moving the armature through the working gap. This feature is disclosed in commonly assigned, commonly filed (Attorney Docket No. 99P7609US) application entitled “Compressed Natural Gas Fuel Injector Having Magnetic Pole Face Flux Director,” the disclosure of which is incorporated herein by reference. Additional features are disclosed in commonly assigned, commonly filed (Attorney Docket No. 99P7610US) copending application entitled “Compressed Natural Gas Injector having Gaseous Dampening for Armature Needle Assembly during Opening,” the disclosure of which is incorporated herein by reference.
In addition, as shown in FIG. 4, radial slots in the form of recessed surfaces 18 a are provided in the lowermost surface of inlet connector 18 to reduce the effective contact surface area between the armature and the inlet connector by about one third of the total cross-sectional area which was utilized in prior art conventional injectors. This configuration provides six coined pads 18 b of about 0.05 mm in height, thus creating six corresponding rectangular shaped radial slots 18 a to provide fuel flow paths. By reducing, the effective surface area of the lowermost face of the inlet connector 18 as shown, the tendency to develop an attractive force between the inlet connector 18 and the armature 14 is significantly reduced to about one-third of its original value, and the ability to tolerate fuel contaminants at the interface without producing an attractive force therebetween is also significantly increased. As noted, preferably, the rectangular radial slots 18 a are of a shallow depth, i.e. about 0.05 mm, (i.e., millimeters) in order to provide the benefit of reducing the inlet connector/armature interface surface area while still providing a relatively unobtrusive location for collection of solid contaminants which are ultimately removed by the flow of gaseous CNG.
As noted, the provision of recessed surfaces 14 a in the lowermost surface of inlet connector 18 creates raised pads 18 b on the surface, which pads improve the tolerance of the injector to fuel contaminants in several ways. The recessed surfaces 18 a may be made by any suitable process, but are preferably coined. The first effect is to reduce the contact area of the inlet connector at the armature interface, thereby significantly reducing any attractive force generated therebetween by liquid contaminants such as oil or water. Furthermore, as noted, the radial pads 18 b provide hidden areas between the pads where contaminants can collect without affecting the operative working gap 15 until being drawn away by the fuel flow. The working gap for gasoline is about 0.08 mm to about 0.14 mm, and about 0.3 mm for compressed natural gas. In addition, as noted, the provision of the six rectangular recessed portions in the form of slots 18 a and six raised pads 18 b , each having a generally trapezoidal shape, on the inlet connector, provide a unique fuel flow path past the inlet connector/armature interface in a manner which causes the gaseous fuel to pass transversely through the working gap 15 as shown at 56 in FIG. 5 and allow for the control of the fuel flow around and through the armature by controlling the pressure losses.
Also, by controlling the sizes of the recessed surfaces 18 a and raised pads 18 b , and the various apertures 58 , 60 , 66 in the armature and the valve body as will be described—as well as the numbers and combinations of such openings—the fuel flow can be controlled over at least three flow paths and pressure losses can also be controlled. For example, a small pressure differential across the armature while fully open, assists spring 30 during breakaway upon closing and provides dampening on opening impact. The additional fuel flow path also reduces the possibility of contaminants collecting above upper guide 36 as shown in FIG. 2 . In summary, numerous combinations of apertures and sizes thereof—as well as slots and pads on the fuel inlet connector—can be made to direct the gaseous fuel flow in any desired manner which is best for optimum fuel burning and engine application.
Referring now to FIGS. 5 and 6 in conjunction with FIGS. 1-3, there is illustrated still another significant improvement, which renders the fuel injector assembly more fully capable of operation with CNG. In prior art injectors which were used with relatively contaminant free fuels the fuel would pass through the filter down through the inlet connector into the armature and out an opening positioned relatively close to the lowest portion of the armature which was located substantially immediately above the valve aperture. In the present structure there is provided a relatively diagonally oriented aperture 58 shown in FIG. 5, which directs the CNG flow therethrough and downwardly toward valve aperture 41 for entry into the intake manifold of the internal combustion engine.
As shown in FIG. 5, aperture 58 forms a generally acute angle with longitudinal axis A—A of the fuel injector 10 . In addition, the armature of the present invention provides at least one side opening 60 which is generally transverse to the longitudinal axis A—A, to permit fuel flowing downwardly through the center of the armature to be directed sidewardly out of the armature and thereafter downwardly toward the valve aperture 41 shown in FIG. 1 . In the embodiment shown in FIG. 1, aperture 60 is generally horizontal, but may be oriented at an acute angle to the longitudinal axis if desired. Aperture 58 is not shown in the cross-sectional view of FIG. 1 . The fuel flowing through aperture 60 is indicated by the flow lines 62 and the fuel flowing through aperture 58 is indicated schematically by flow lines 64 . Optionally several additional horizontal apertures 60 may be provided in the armature at different radial locations thereabout, or alternatively as shown, one aperture 60 may be provided, depending upon the fuel flow pattern sought in each particular instance. It can be seen that the fuel flow from the fuel inlet connector 18 is divided into three paths, a first path expanding across working gap 15 , a second path through aperture(s) 60 , and a third path through aperture(s) 58 . The first path extends between the armature 14 and the magnetic coil 28 and is ultimately joined by the second flow path passing through aperture(s) 60 .
It can also be readily appreciated that the diameters of each aperture 58 , 60 can be varied to direct the fuel flow in any predetermined desired direction. For example, by reducing the size of apertures 58 , 60 fuel will be encouraged to flow with increased volume cross the working gap 15 . Alternatively, increasing the diameter of apertures 58 , 60 will attract greater volume of fuel through those apertures and thereby reduce the fuel flow across the working gap. It has also been found that the diameters of the apertures 58 , 60 and the numbers and locations of such apertures affect the damping characteristics of the valve needle 16 , both upon opening and upon closing. Accordingly, the diameter of fuel flow apertures 58 , 60 and the numbers, locations, and orientations of such apertures will depend upon the desired volumetric flow characteristics and desired flow patterns in each instance; however diameters within the range of 1-2 mm have been found to be preferable.
Referring now to FIG. 6, a valve body 34 is also provided with central fuel flow opening 35 and several diagonally oriented fuel path apertures 66 which are intended to receive the CNG fuel flowing from the first and second flow paths from the working gap 15 and aperture(s) 60 along the sides of the armature 14 and to redirect the fuel downwardly toward the valve aperture 41 such that when the needle 16 is lifted, the fuel is permitted to enter aperture 41 and thereafter directed into the intake manifold of the engine, neither of which are shown in the drawings. Fuel flowing along the third flow path through aperture(s) 58 lead directly toward aperture 41 . It has been found that the unique provisions of the apertures 58 and 60 —as well as rectangular radial slots 18 a on the inlet connector lowermost face—create a fuel flow pattern which induces the CNG to flow in the manner shown by the fuel flow lines at 56 , 62 and 64 in FIG. 5 and such fuel flow lines actually create ideal pressure conditions to avoid causing the armature to be attracted to the inlet connector. Thus the attractive forces between the armature and inlet connector are minimized by the several factors mentioned, namely the elimination of the tendency of the oil and contaminates to accumulate in the space 15 located between the armature and the inlet connector, the reduction of the effective inlet connector/armature interface area by provision of radial pads on the face of the inlet connector, and the provision of the unique CNG flow pattern which creates a force free environment between the inlet connector and the armature.
As indicated, alternatively, apertures 60 may be provided in several locations about the circumference of the armature, and apertures 58 may be provided in several locations thereabout. Also their angular orientations may be varied. However, it has been found that a single aperture on each side, as shown is sufficient to produce the desired flow path and the force free environment. Also, as noted, it should be noted that the diameter of each aperture can be altered in order to provide control of the fuel pressures and flow patterns in the areas surrounding the inlet connector, the armature, and the valve body, so as to provide a predetermined fuel flow pattern throughout the injector as may be desired. This feature is more fully disclosed in the aforementioned commonly assigned, commonly filed (Attorney Docket No. 99P7610US) copending application entitled Compressed Natural Gas Injector Having Gaseous Damping for Armature Needle Assembly During Opening.
It should also be noted that the presence of the diagonally oriented fuel flow apertures 66 in valve body 34 eliminates the problems of prior art injectors wherein debris and contaminants would accumulate in the area of the upper valve guide 36 , causing abrasive action and intermittent guidance between the upper guide 36 and the armature 14 . Thus, the provision of the diagonally oriented apertures 66 in valve body 34 encourage the flow of CNG past the area surrounding the upper guide 36 and eliminate any accumulation tendencies for contaminants in the area of upper guide 36 .
Referring now to FIGS. 7 and 8 in conjunction with FIGS. 1-3, there is illustrated an alternative embodiment of the lower end portion of the inlet connector 18 and the lowermost face of the inlet connector 18 . In this embodiment inlet connector 18 includes arcuately chamfered surface 52 on the lowermost end of inlet connector 18 as in the previous embodiment. In FIG. 8, the lowermost surface of inlet connector 18 defines a surface area 67 between concentric circles 70 and 72 as shown. While the inlet connector/armature contact area is not reduced as in the embodiment of FIGS. 3 and 4, the operation of the injector is improved over the prior art injectors. Accordingly, the alternative embodiment as shown in FIGS. 7 and 8 will provide substantially improved operation for the injector as shown as compared with prior art injectors when utilized with CNG.
Referring to FIGS. 9 and 10 in conjunction with FIGS. 1-3, there is shown still another alternative embodiment of the armature configuration for use with CNG the armature in valve assembly configuration for use with CNG. In FIG. 9 the armature assembly 73 contains a diagonally shaped relatively large fuel flow opening 74 at the lower portion thereof, while the horizontal fuel opening 60 in the armature of FIG. 5 has been eliminated. In addition, in the valve body 76 shown in FIG. 10, central flow opening 75 is provided, and the diagonal fuel flow openings 66 of the embodiment of FIG. 6 have been eliminated and the fuel flow as depicted at 71 in FIG. 10 will therefore be directed out of diagonal aperture 74 and into valve assembly 76 as shown in FIGS. 9 and 10.
The CNG fuel path created by the combination of the inlet connector and armature shown in FIGS. 7-10 represents a significant improvement over prior art structures. However, the armature and valve assembly shown in FIGS. 3-6 are preferred. It should be noted that the structures disclosed in FIGS. 7-10 produce satisfactory and improved operation and may alternatively be considered to be a preferred embodiment, depending upon the particular environment in which they are utilized. For example, in certain injectors dimensional and clearance considerations may very well create a flow pattern which will mandate a preference to utilizing the embodiments of FIGS. 7-10 as opposed to the previously disclosed embodiments of FIGS. 3-6.
Referring now to FIGS. 11 and 12 in conjunction with FIGS. 1-3, there is disclosed an enlarged elevational view of the improved armature of the present invention, the improved valve body of the present invention, and the improved valve needle which has been incorporated into the disclosed structure. In particular, the armature 14 contains side fuel flow aperture(s) 60 and the valve body 34 contains the diagonal CNG fuel flow path openings 66 . The armature 14 has attached thereto by a known crimping procedure at 78 , an improved valve needle 16 .
The improved valve components of the present fuel injector are disclosed in FIGS. 1, 11 and 12 incorporating the improved needle 16 . During operation of the fuel injector, the armature 14 moves upwardly and downwardly due to the energization and deenergization of coil 30 so as to produce alternating opening and closing contact between valve needle 16 and valve seat 40 . As the needle is raised to permit the CNG fuel flow through the aperture 41 the flow passes the tip portion 17 of the needle and enters aperture 41 in its flow path toward the intake manifold of the engine.
In conventional liquid fuel injection systems having a conventional elongated needle having a continuous cylindrically shaped outer surface, the needle presents several problems and disadvantages. When applied to CNG systems, the problems inherent with conventional needles are intensified, particularly due to the changes in the gaseous environment as compared to the liquid environment. Accordingly, the present invention incorporates a novel valve needle which improves the operation characteristics of fuel injection systems, including liquid fuel and gaseous fuel types.
It has been known that when conventional valve needles engage a valve seat of a fuel injector the force of impact with conventional needles can generate sounds within the engine compartment which are generally perceived as either a mechanical problem or otherwise harsh or objectional noises emanating from the engine. This force of impact—which is equal to the valve component mass multiplied by the acceleration—is generally caused by the relatively substantial velocity of the needle during its movement toward the “valve closed” position in engagement with the valve seat. Accordingly, the needle 16 which forms part of the present injection system, has been structured to eliminate disadvantages of prior art needles. Although this needle has been found to improve performance with gaseous fuel injection systems as in the present invention, it has also been found to improve the performance of liquid fuel injection systems.
With the improved needle shown in FIG. 11, it has been found that it is desirable to provide a generous radius sealing portion 19 at the valve end of the needle in order to maximize the contact area between the valve needle 16 and the valve seat 40 . For example, the greater the radius at the tip of the needle, the better the sealing between the needle and the valve seat 40 . Preferably, the radius of the spherical sealing section 19 of needle 16 is in the order of about 1.75 millimeters (i.e., mm), or about 1.5 times the radius of the corresponding sealing surfaces in the prior art structures. However, needles which are generally known for conventional injectors of the type disclosed herein generally have a continuous outer cylindrical configuration from the upper end to the lower end, thus requiring a needle of relatively large needle cross-sectional area in order to provide a relatively large sealing surface. The needle 16 of the present invention as shown in FIG. 11 is a relatively low mass needle as disclosed, yet includes a relatively large spherical sealing surface.
In particular, the mass of the needle has been substantially reduced by reducing the cross-sectional dimension of the shaft 21 of the needle and retaining a tip portion 17 which is greater in cross-sectional dimension then the shaft of the needle as shown. This configuration effectively reduces the mass of the needle while retaining the relatively large sealing diameter of spherical surface 17 b of the tip portion 17 so as to provide a relatively generous radius at the tip—or free end—portion of the needle for engagement with the valve seat 40 . It has been found that the relatively reduced mass of the needle and the relatively large radius of the tip portion 17 makes it possible to provide a generous spherical sealing surface 19 for the needle for a given amount of CNG flow. The generous radius also results in a shorter traveling distance for the needle 16 thereby reducing the impact velocity of the needle relative to the valve seat. It has been determined that for a predetermined flow rate, this configuration results in a significant reduction of the noise produced by the impact between the needle 16 and the valve seat 40 . Furthermore, the attenuation of the apparent noise is a result of reducing the amplitude (via reduction of lift of the needle 16 ) and lowering the frequency (via the greater impact radius of tip portion 17 ) of the noise into a less objectionable region of the sound spectrum as perceived by the human ear.
In addition to reduced noise, the improved needle of the present invention provides a larger guide surface relative to the mean needle diameter, thereby improving the wear resistance of the guiding surface of lower guide 80 shown in FIG. 11 . This improved wear resistance of the guide surface is due to the reduced loading compared to that of a conventional base valve guide diameter which was used with needles of the prior art. For example, a typical prior art needle will have a substantially continuous cylindrically shaped shaft which terminates at a radiussed end portion wherein the shaft diameter may be twice as much as the diameter of the shaft of the improved needle shown in FIG. 11 . On the other hand, the tip portion 17 of the needle shown in FIG. 11 can be configured to have a diameter up to approximately 50% greater than the diameter of the shaft 19 of needle 16 thereby having a greater diameter than would otherwise be present in a prior art needle and thereby making provision for a lower guide 80 having a guide surface which is greater in diameter and surface area than would otherwise be utilized with prior art needles. This improves the wear resistance of the guide surface due to the reduced loading as compared to that of the conventional base valve guide diameter. Significant features of the needle disclosed herein are also disclosed in commonly assigned, commonly filed (Attorney Docket No. 98P7678US01) application entitled “Compressed Needle Gas Injector Having Improved Low Noise Valve Needle,” the disclosure of which is incorporated herein by reference.
In FIG. 13, the preferred dimensional relationship between the improved needle 16 and the funnel shaped valve needle rest 42 is shown in greater detail. As noted with respect to FIG. 1, needle 16 includes a central shaft portion and a cylindrical needle tip portion 17 having a spherical lower surface 17 b which engages the frusto-conically shaped surface 42 of needle rest 40 . The needle is guided by upper guide 36 guiding armature 16 as shown in FIG. 1, and lower guide 80 guiding needle tip portion 17 as shown in FIGS. 13 and 14. Upper guide 36 is inherently required to provide a space 36 a between the guiding surface and the armature 14 , to permit the upward and downward motion of the armature and needle. Thus the armature 14 and needle 16 may have the tendency to shift to the left or right at the upper guide 36 within space 36 a which is about 0.10 to about 0.15 mm on the diameter, preferably about 0.13 mm.
Referring now to FIG. 13, it has been found to be advantageous to locate the center of generation 17 c of spherical sealing surface 17 b of needle tip portion 17 at the center of the lowermost surface of lower guide 80 as shown, in order to assure precise seating and sealing of needle 16 on frusto-conical needle rest 42 . In particular, by such positioning of the center 17 c of spherical sealing surface 17 b of tip portion 17 , the lower guide 80 tends to constrain sideward movement of the needle tip portion 17 due to movement of armature 16 within upper guide 36 , and effectively becomes a nodal point about which needle tip portion 17 is capable of rotating over 360 degrees of motion. Thus any sideward movement of the needle which occurs at the level of armature 14 and upper guide 36 , will cause the needle to pivot about the center point 17 c and promote self seating of sealing surface 17 b on needle rest 40 . This self-seating feature also applies in the event that any misalignment or manufacturing tolerance buildup occurs in the relationship between upper guide 36 and needle 16 .
As noted, the present needle 16 is advantageous for use with injectors, which utilize CNG as is contemplated herein, as well as with injectors which utilize liquid fuels, such as gasoline. In particular, in injectors utilizing liquid fuels, the motion of the valve needle is also damped by displacement of fluid across the extended valve seal face and the valve seat which further reduces the impact force and uncontrolled secondary injections upon closure caused by the valve needle when it rebounds away from the valve seat. In such injectors used with liquid fuels, valve rebound produces quantities of low velocity fuel droplets after the needle started to close. Valve rebound dampening minimizes low volume/velocity fuel transfer to the aperture 41 . Thus, the dampening of the needle rebound improves the operation of the injector by minimizing low volume/low velocity fuel transfer to the orifice and the surrounding area which tends to extendedly suspend fuel droplets via surface tension when liquid fuels are used. Valve rebound dampening has also been found to be beneficial in the present injector which is contemplated for use with gaseous CNG.
Referring now to FIG. 14, in conjunction with FIG. 11, lower valve needle guide 80 is illustrated in the form of a disc shaped member having arcuately shaped fuel passage apertures 82 which direct the gaseous CNG in a more efficient and effective manner as compared to prior art valve guides which utilized a plurality of circular openings formed along a circular pattern. The apertures 82 are larger than the prior art circular apertures and are more effective in directing and controlling the fuel flow in an efficient manner by forming the flow pattern into several arcuate flow paths.
Referring now to FIG. 12, the improved armature 14 is illustrated with valve needle 16 crimped thereto at 78 by known crimping procedures; however, valve body 34 has been eliminated for purposes of clarity of illustration in the enlarged view of armature 14 and needle 16 . In FIG. 12, the illustration of needle 16 clearly shows the main shaft portion 21 and the enlarged tip portion 17 with enlarged valve spherical sealing surface 17 b which conveniently engages and disengages seat area 42 of valve needle rest 40 as described in conjunction with FIG. 13 .
Referring again to FIG. 11, the injector 10 incorporates a fuel columnating jet device 84 which includes a shallow funnel shaped section 86 connected to a generally tubular shaped columnating section 88 . Gaseous fuel passing through valve aperture 41 is then allowed to pass through funnel shaped section 86 , and then to be columnated into a steady gaseous stream in columnating section 88 . The fuel columnating device 88 enhances mixture quality, reduces fuel delivery time and enables single or multiple discharge orientation for improved gaseous flow targeting. A narrow gaseous flow discharge angle can entrain the surrounding working fluid (mostly air) and can impart useful turbulent energies to directed air/fuel mixtures flowing through a port, intake valve and/or into a combustion chamber to reduce in-cylinder air/fuel mixture gradients. This feature has proven to significantly reduce engine misfire and to improve exhaust emissions, and is also disclosed in commonly assigned, commonly filed (Attorney Docket No. 99P7611US) application entitled “Gaseous Injector With Columnated Jet Orifice and or Flow Directing Device,” the disclosure of which is incorporated herein by reference.
It has been found that the injector of the present invention provides improved operation for the reasons stated hereinabove by improving the flow pattern of the CNG as described, improving the control over the valve needle operation and movements thereof, and improving the sealing characteristics of the needle type valve incorporated as part of the injector. As noted hereinabove, noise characteristics and needle dampening both upon opening and upon closing, have been significantly improved by the present invention and with the result that the injector as shown and described is significantly improved for use with compressed natural gas (CNG) fuels.
Although the present invention is particularly intended for use with CNG fuels, it is self evident that the use of any liquid or gaseous fuels are contemplated, particular those fuels which are relatively high in contamination, since the tolerance of the contaminants has been fully addressed by the disclosed structures.
Although the invention has been described in detail with reference to the illustrated preferred embodiments, variations and modifications may be provided within the scope and spirit of the invention as described and as defined by the following claims.
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An electromagnetically actuable fuel injector for an internal combustion engine is disclosed having an outer housing, a fuel inlet connector positioned in the upper end portion of the outer housing for reception of fuel therein, and an armature having a valve needle attached thereto and positioned adjacent the fuel inlet connector and spaced therefrom by a working gap. The armature defines a generally elongated central opening to receive fuel flow from the fuel inlet connector and has valve needle attached thereto which interacts with a fixed valve having a fixed valve seat associated with the housing to selectively permit fuel to flow through a valve aperture associated with the fixed valve seat. The fuel inlet connector has a fuel outlet end facing a fuel inlet end of the armature and includes a plurality of radially extending raised pads separated by a corresponding plurality of radially extending recessed portions to reduce the contact area between the fuel inlet connector and the armature when the armature is moved upwardly, and to promote fuel flow transversely across the working gap therebetween to establish a first fuel flow path outside of the armature. The first fuel flow path prevents contaminants from accumulating in the working gap. The armature includes at least one first aperture extending through a wall portion thereof for receiving fuel flow from the generally elongated central opening and for directing the fuel flow to a second flow path toward the fixed valve seat. At least one-second aperture extends through a wall portion of the armature and extends at a generally acute angle relative to the longitudinal axis to establish a third fuel flow path toward the fixed valve seat. The size, orientation and numbers of the apertures can be varied to achieve predetermined flow conditions. A method of directing fuel through an injector is also disclosed although the fuel injector and method disclosed utilize gaseous fuels, all types of fuels are contemplated.
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CLAIM OF PRIORITY
The present application claims priority from EP Patent application serial No. EP09166512.5 filed on Jul. 27, 2009, the content of which is hereby incorporated by reference into this application.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a method and a control system for controlling an auxiliary device of a vehicle, wherein the auxiliary device can be automatically started at a starting time which is determined based on an estimated departure time of the vehicle. In particular, the invention relates to an air-conditioning device which can be automatically started for pre-air-conditioning (PAC) based on an estimated departure time of an electric and/or hybrid vehicle.
2. Description of the Related Art
In electric vehicles, the maximum cruising distance of the vehicle is limited due to the limited capacity of the batteries. If air-conditioning equipment is employed while cruising, this air-conditioning equipment consumes energy which is therefore not available for driving. As a result, the maximum cruising distance is shortened due to the employment of the air-conditioning equipment.
It may be possible to employ pre-air-conditioning (PAC) while the vehicle is connected to an external power supply for battery charging. The pre-air-conditioning is started at a programmable starting time prior to an estimated departure time of the electric vehicle. The pre-air-conditioning cools or heats the passenger cabin of the vehicle while the vehicle is connected to the battery charger such that the air-conditioner draws the energy from the battery charger connection and not from the battery. As a consequence, the passenger cabin is air-conditioned at the time of departure and the amount of energy consumed by the air-conditioning equipment while the vehicle is driving may be reduced. As a result, the maximum cruising distance may be increased.
However, it is a difficult task to estimate the optimum starting time of the operation of the air-conditioning device because the departure time is often unknown. Even if the driver is commuting, the basically periodical use of the vehicle may be disturbed by irregular events. The starting time of the pre-air-conditioning can be determined within an ordinary timer control. The driver may specify his departure time manually in advance and the vehicle starts the pre-air-conditioning operation accordingly.
The starting time of the pre-air-conditioning operation may also be directly programmed by the driver. However, it may be inconvenient for the driver to manually specify the departure time and/or the starting time of the pre-air-conditioning prior to every driving. If the starting time of the pre-air-conditioning is not correctly determined, the energy may be employed in an ineffective way. If the pre-air-conditioning is started too early, the air-conditioning equipment operates for an interval which is too long and therefore uses too much energy or stops after a pre-determined fixed time and the temperature in the vehicle will go back to the initial temperature so that the inputted energy is wasted, while on the other hand, a too short period of pre-air-conditioning may result in an incorrect temperature at the departure time. These problems will lead to the necessity of using valuable battery power of the vehicle after its departure. Similar problems may occur in vehicles having programmable seat-heaters or an auxiliary heating often used in countries with a colder climate.
From a more general point of view, the problem may relate to any auxiliary device of a vehicle that consumes electrical power, where the starting time of the auxiliary device may depend on the departure time of the vehicle. For example, a vehicle driver might want to synchronize his vehicle multimedia files, e-mails etc. with the data from his home network shortly before leaving with his car. Although in non-electric vehicles the battery power issue is not as crucial as in electric vehicles, an incorrect timer programming may result in either a loss of energy or in a reduction of comfort.
The document JP 2007-269161 A teaches an air-conditioner control device which starts an air-conditioning device using a statistical approach based on a frequency function. This device, however, cannot react to changes in the driver's habits, e.g. if he departs later or earlier as usual etc.
SUMMARY OF THE INVENTION
It is an object of the invention to provide a method and a control system for controlling at least one of an auxiliary device of a vehicle enabling a more flexible and more precise automatic determination of an activation time of said auxiliary device in order to increase the cruising range of the vehicle and the convenience for the driver.
This object is achieved according to the features of the independent claims. The dependent claims refer to preferred embodiments of the invention.
The invention relates to a method for controlling at least one auxiliary device of a vehicle. Preferably, the auxiliary device may be one of a heating device, cooling device and/or air-conditioning device of the vehicle. The heating device may also be a programmable seat-heater or an auxiliary heating (park heating). The auxiliary device may also be an on-board multimedia device, the database of which can be synchronized with the multimedia database of the driver's home network. The vehicle may in particular be an electric vehicle and/or a hybrid car.
The method may include the step of determining a time of usage of at least one home appliance of a user of the vehicle. The method may include the step of determining a departure time of the vehicle based on the time of usage of the at least one home appliance. The method may include the step of determining the necessary starting time of the at least one auxiliary device based on the determined departure time of the vehicle.
If the driver changes his departure time on a daily basis, there may be a strong temporal correlation between the use of the vehicle and the use of one or more home appliances. Home appliances used with a strong temporal correlation with the vehicle may include an electrical kettle, a toaster, a refrigerator, a cooking heater, room light, television, an electronic key for the door, an elevator, an alarm clock, the shower, the toilette, or the like. When the user gets up in the morning, he turns on the room light, checks e.g. some news in the TV, boils water in the kettle, uses a coffee machine or tea machine, opens the refrigerator to take some food, prepares breakfast with a cooking heater or a toaster and then uses the vehicle to go to his office. These processes are typically personally optimized and occur on a regular basis for work days. Eventually different schedules can be employed for holidays and vacations. Therefore, at least on work days, there is typically a strong correlation between the time of vehicle departure and the time of usage of the home appliances. When the driver needs to leave the house at 7:30 h, he or she uses for example the cooking heater at around 6:30 h while the cooking heater would be used at 7:00 h when he or she needs to leave at 8:00 h. The invention uses this relative correlation between the departure time of the vehicle and the time of usage of at least one home appliance in order to precisely and at the same time flexibly determine the departure time of the vehicle on a relative basis. The invention allows for a relative determination of the starting time instead of an absolute fixed time for a start- or an activation time of the auxiliary device of the vehicle.
This departure time may be used to switch on the at least one auxiliary device, e.g. the air-conditioning equipment for pre-air-conditioning, at some interval before the estimated departure time of the vehicle.
The automatized starting of the auxiliary device is employed only when the vehicle is connected to a charger power supply in case the vehicle is an electric vehicle and/or hybrid vehicle powered by batteries. In this case, increased energy efficiency can be obtained.
The step of determining the departure time of the vehicle may include determining time differences between prior times of usage of at least one home appliance and subsequent departure times of the vehicle based on usage data of the at least one home appliance and of the vehicle stored in respective usage databases. The determined time differences may then be averaged in order to obtain an average time difference between the time of usage of a particular home appliance and the subsequent departure time of the vehicle. The usage data may be stored in a storage system of a home appliance control system and/or of the electric vehicle.
In other words, data describing the previous usage of the at least one home appliance, e.g. the usage in the past days, week, or month, etc., are stored in a database and may be used in combination with stored data on the respective departure times of the vehicle, i.e., the subsequent departure time of the vehicle that followed a past usage of the at least one home appliance, to determine an average time difference between the respective usage of the home appliance and the actual departure times of the vehicle. Having determined such an average time difference for the at least one home appliance, the next departure time of the vehicle may be estimated by adding the determined average time difference to a current usage time of this home appliance. The determined departure time is therefore an estimated departure time (which may still deviate slightly from the actual departure time). Due to this averaging, the pre-heating or pre-cooling operation may be started at a time that enables optimized mean energy consumption, while at the same time, increases the convenience for the driver.
In order to further improve the accuracy and reliability of the determination of the departure times of the, a variance of said time differences may be determined for a plurality of home appliances, wherein the home appliance used for determining the departure time of the vehicle having the smallest variance of the time differences will become a trigger appliance. The home appliance showing the lowest variance is the one the usage of which is most correlated with the usage of the vehicle. This home appliance is selected in order to enable a trustworthy prediction of the departure time. The departure time can be estimated based on the average time differences between the usage of multiple home appliances and the departure time of the vehicle, wherein the departure time may be estimated using some weighted average of the values obtained from the various home appliances.
Two or more home appliances may be selected as potential trigger appliances and prioritized based on their variance or correlation values, wherein a potential trigger appliance may be a home appliance having a determined variance value that is smaller than a pre-determined value in order to filter out home appliances not suitable for estimating a departure time. An appliance out of the set of potential trigger appliances that is last used by the user may be selected as the actual trigger appliance. It may be advantageous to have more than one potential trigger appliance in case the driver uses differing appliances over the time or in case the driver uses a second home appliance with a lower variance after he has used a first appliance with a higher variance value relative to the second home appliance. The starting time of the auxiliary device may then be updated based on the usage time of the second appliance, enabling a more accurate forecast of the vehicle departure time.
It is possible to implement some more sophisticated algorithms for determining the estimated departure time, e.g. based on neural networks evaluating the actions of the driver or by using correlation algorithms that underweight and/or exclude statistical anomalies in case the usage data for the vehicle and home appliances shows statistical blips. By way of example, the driver may use the coffee machine from Monday through Friday about 30 min. before leaving with the vehicle, with the exception of Wednesdays, where he goes running instead of making coffee. An algorithm capable of recognizing and then underweighting and/or excluding such statistical anomalies may then identify the coffee machine as the most reliable trigger appliance for week-days except for Wednesdays. On Wednesdays, another trigger appliance would be used instead of the coffee machine.
In particular, it is proposed that said step of determining the departure time of the vehicle may include determining a correlation between prior times of usage of at least one home appliance and subsequent departure times of the vehicle based on usage data of the at least one home appliance and of the vehicle stored in one or more databases.
A biasing of the estimations due to the mixing of working days and holidays can be avoided if the averages, variances and/or correlations are determined based on stored usage data relating to working days.
In case the driver's schedule varies with the working days, the average and/or variance can be calculated separately for different working days or time intervals. For the prediction of departure times during holidays, different data obtained for holidays only may be employed. In order to further improve the accuracy, a different trigger home appliance might be prioritized for different time periods by selecting the home appliance that, for a given time period of a day, week, or month, is showing the lowest variance and best correlation with the usage of the vehicle.
The determining of the variances and/or the correlations may be repeated at regular intervals, e.g. weekly, in order to account for changing preferences of the driver.
Moreover, it is possible to predict the departure time of the vehicle based on the type of usage of the home appliance selected as the trigger appliance. If e.g. the driver uses a coffee machine for making an espresso, this might indicate that he is in a hurry and that the departure is rapidly approaching, while using a coffee machine to make a cappuccino might indicate that the time schedule is more relaxed. This type of correlation may in particular be learned by a neural network implemented in the control system.
According to another aspect of the invention, the method may comprise the step of determining the sequence of usage of a plurality of home appliances before using the vehicle and selecting the trigger appliance based on the determined sequence in order to more accurately determine the departure time of the vehicle. For example, the vehicle driver would normally use a first sequence of home appliances if he was on a regular schedule on a work day, such as the light switch in his bed-room, followed by the light switch in the bath room, followed by the coffee-machine. But if he was on a more relaxed schedule, he could use a second sequence, wherein he uses the coffee-machine to have break-fast before going to the bathroom. A different trigger appliance and/or different average time difference may be determined for every determined sequence in order to improve the accuracy of the determined estimated departure time of the vehicle.
A further aspect of the invention relates to a control system for controlling at least one auxiliary device of a vehicle, wherein the control system implements the above described method. The auxiliary device may in particular be at least one of a heating device, cooling device, and/or air-conditioning device.
The control system may include means for determining a time of usage of at least one home appliance of a user of the vehicle and control means for determining the departure time of the vehicle based on the time of usage of the at least one home appliance. The control means may be further configured to determine a starting time of the auxiliary device based on the determined departure time of the vehicle and to automatically start the auxiliary device at the determined starting time.
The control system may be used for an electrical or hybrid vehicle and wherein the auxiliary device may be at least one of a heating device, cooling device, and/or air-conditioning device and wherein the system further comprises a connection to a charger power supply for charging batteries of the vehicle, wherein the control means may be configured to start the auxiliary device at said starting time of the operation of the device only if the vehicle is connected to the charger power supply.
The data connection for indicating that a charger power supply is connected to the vehicle may be integrated in the control system controlling the household appliances of the driver. The connection to the charger power supply may be used as a control signal connection for activating and/or enabling the communication between the vehicle and the household control system, which may start the auxiliary device via the control signal connection.
The control system may further include at least one usage database for storing prior departure times of the vehicle and/or prior times of usage of the at least one home appliance, wherein the control means is configured to determine an average time difference between prior times of usage of at least one home appliance and subsequent departure times of the vehicle to estimate the departure time of the vehicle. The at least one usage database may be connected to the household electronics control system.
It may also be possible to use a separate appliance and vehicle usage database for storing the time of usage of the appliance and the vehicle.
This usage database may be used to evaluate the correlations between the usage of the at least one home appliance and the departure time of the vehicle. The usage data of the vehicle may be uploaded from the vehicle to the vehicle usage database via a dedicated signal connection. The control system may further include a temperature sensor for measuring an inside temperature of the vehicle and/or an outside temperature in order to enable a temperature-dependent determination of the starting time of the operation of the auxiliary device.
BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments of the invention will be described by way of examples with reference to the following schematic drawings:
FIG. 1 shows a block diagram of an electric vehicle and a house control network.
FIG. 2 shows a database for storing the time of appliance usage and the actual departure time of the electric vehicle.
FIG. 3 shows a table indicating a calculation of a time interval between the appliance usage and the departure of the electric vehicle.
FIG. 4 shows a table indicating intervals between a time of appliance usage and the departure time of the electric vehicle for several days together with average and variance values.
FIG. 5 shows a flow chart regarding the control of an auxiliary device, e.g. of a PAC.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Further features and advantages of the invention will become apparent from the following description of preferred embodiments of the invention. This description and the claims include multiple features in particular combinations. The skilled person will consider further combinations of the characteristic features of the embodiments in order to adapt the method and/or the control system to further possible fields of application of the invention.
(First Embodiment)
FIG. 1 shows a block diagram of a house 110 including a house control network (home network) and of an electric vehicle 100 . The house 110 comprises means for activating an auxiliary device (AD) controller 102 of the vehicle 100 , which in turn controls an auxiliary device (AD) 101 for e.g. heating and/or cooling a passenger cabin of the vehicle 100 . The device 101 can be an air-conditioning system (AC) which may be supplied with energy either by a battery 104 of the electric vehicle 100 or by a charger power supply 117 of the house if the vehicle 100 is connected to the charger power supply 117 via an electrical connection means 107 .
The connection means 107 can include power lines 108 for charging the battery 104 and signal lines 109 a , 109 b for transmitting low-voltage control signals. The signal line 109 a enables a communication between a scheduler 116 located in the control unit of the house and the AD controller 102 located in the vehicle 100 . The signal line 109 b enables a communication between a navigation device 105 of the vehicle 100 and a vehicle usage database 114 located in the house 110 . If the connection means 107 are activated by connecting a connector upon arrival of the vehicle 100 in a garage or the like, the usage data of the vehicle 100 can be uploaded to the vehicle usage database 114 in the house 110 and are recorded therein. The house 110 comprises multiple household appliances 111 like a cooker, a kettle, light bulbs, a hot water preparing system, a coffee machine, a refrigerator, etc.
The operation of the appliances 111 is detected via an appliance monitor 112 . The usage data detected by the appliance monitor 112 , in particular the starting time and the end time of the appliance usage, are stored in an appliance usage database 113 . Based on the data in the appliance usage database 113 and in the vehicle usage database 114 , an appliance selector 115 calculates averages and variances of intervals between the usage of an appliance 111 and the actual time of the departure of the vehicle. The appliance selector 115 selects one of the appliances 111 as a trigger appliance triggering the auxiliary device activation, e.g. an air-conditioning device of the vehicle 100 , based on the above-mentioned calculation.
A vehicle scheduler 116 is connected to the appliance monitor 112 and a trigger condition memory 118 . When the appliance monitor 112 detects the usage of an appliance and an ID of the appliance is the same with that stored in the trigger condition memory 118 , the scheduler 116 predicts the time of the vehicle departure, which is the current time plus an average interval stored in the trigger condition memory 118 . The predicted time of the vehicle departure is then sent to the auxiliary device controller 102 , e.g. the AC controller of the electric vehicle 100 .
FIG. 2 shows the appliance usage as stored e.g. in the appliance usage database 113 with the vehicle departure times stored e.g. in the vehicle usage database 114 . As can be seen from the table in FIG. 2 , the usage of the respective appliances A, B, C are different for the different days 1, 2, 3, 4, 5, wherein day 1 may stand for Monday, day 2 may stand for Tuesday, etc. As can be also derived from FIG. 2 , the actual departure time of the vehicle is different for each day.
Using the data as shown in FIG. 2 , a time line can be evaluated as shown in FIG. 3 . It can be seen that e.g. the time between the usage of the appliance C and the actual departure of the vehicle is 30 minutes. The time between the usage of the appliance A and the departure of the vehicle is 60 minutes and the time between the usage of the appliance B and the departure of the vehicle is 70 minutes. These interval times between the appliance usage and the departure of the vehicle are calculated for each relevant appliance for each relevant day.
The interval times as mentioned above are shown for the different days and the different appliances in the table of FIG. 2 . In the two last lines the results of a calculation of average values and variance values are shown being performed by the appliance selector 115 as mentioned above.
As can be seen, the average values and the variances differ strongly from each other. If the variance is large it can be concluded that there is a weak correlation between the time of the appliance usage and the time of the actual vehicle departure. On the other hand, if the variance is small it can be concluded that there is a strong correlation between the time of the appliance usage and the time of the actual vehicle departure. Based on this result, the appliance selector 115 can chose the appliance 111 with the smallest variance as a trigger appliance to start the activation of the auxiliary device 101 , e.g. to start the pre-air-conditioning. The appliance selector 115 can store the ID of the respective appliance 111 (e.g. appliance A, B, C . . . ) in the trigger condition memory 118 . Furthermore, the appliance selector 115 can store the respective average interval of the selected appliance 111 in the trigger condition memory 118 .
In the example of FIG. 4 , the appliance A is chosen as the trigger appliance and the average interval is 59 minutes. The selection of the trigger appliance based on the calculation of the average values and the variance values can be done cyclically for example once a day, once a week or once a month (cyclic time period). The selection and the determination of the trigger appliance together with its average interval, as mentioned above, can also be influenced by specific changes of the vehicle usage by the driver. It may be e.g. possible that within a cyclic time period of e.g. one week, in which the same trigger appliance is used and in which the same calculated average interval is used to predict a departure time of the vehicle, the cyclic use of these data is stopped and a new calculation is started, when the actual departure time of the vehicle deviates from the estimated departure time by more than a predetermined value. Such a predetermined value may by e.g. 10% of the predicted and prestored time interval (in case of FIG. 4 : 10% of 59 minutes).
After the preselected cyclicity has been stopped by a new calculation, the preselected cyclicity can be started again. It may also be possible to lengthen or to shorten the cyclicity depending on a comparison between the actual departure times of the vehicle and the estimated (calculated) departure times of the vehicle.
Regarding the calculation of the appropriate variance it shall be mentioned that each row in FIG. 2 should be the data of the same day and the same time period, meaning that the time of the actual vehicle departure is that of just after the usage of the appliances B, A, C as shown in FIG. 3 .
As mentioned above, when the appliance monitor 112 detects the usage of an appliance and the ID of the appliance is the same with that stored in the trigger condition memory 118 , the vehicle scheduler 116 predicts the time of the vehicle departure, which is the current time plus the average interval stored in the trigger condition memory 118 . The predicted time of the vehicle departure is then sent to the auxiliary device controller 102 , e.g. the AC controller of the vehicle 100 so that, the controller 102 can decide the starting time of the auxiliary device 104 by the predicted time of the vehicle departure instead of the specified time by the driver.
A map 103 may be provided for storing the activation and/or starting times of the air conditioning device 101 which has been downloaded from the scheduler 116 . The map 103 can be updated when the vehicle 100 is connected via the connection means 107 .
Accordingly, the invention provides for a relative determination of the starting time of the auxiliary device instead of an absolute fixed time for a start- or an activation time of an auxiliary device 101 of the vehicle 100 . This gives a large enhancement to the accuracy of the determination for the starting times and/or the activation times of auxiliary devices 101 which lead to an increased energy efficiency as mentioned above.
The above described signal connections between the vehicle 100 and the house 110 may be replaced with wireless data connections in alternative embodiments of the invention.
The auxiliary device controller 102 interacts with a timer 106 for starting e.g. the air conditioning device at a suitable time interval prior to the estimated departure time of the vehicle 100 . This time interval may be influenced based on the outside temperature and on the temperature inside the vehicle 100 which may be determined using suitable temperature sensors (not shown).
If the appliance monitor 112 detects the usage of one particular trigger appliance 111 , e.g., the usage of an electric kettle, refrigerator, a cooking heater, room light, a television, an electronic key for a door and/or an elevator, the scheduler 116 calculates the estimated departure time of the vehicle 100 by adding the prestored average time difference between the operation of the appliance 111 and the departure of the vehicle 100 to the actual time.
The appliance usage database 113 records the time of usage of each appliance detected by the appliance monitor 112 . The vehicle usage database 114 records the times of the vehicle departures which are detected, e.g. by a navigation device 115 located in the vehicle 100 . The appliance selector 115 calculates the average and variance of the time intervals between the appliance usage and the time of the vehicle departure in order to choose a particular trigger appliance for triggering the start of an auxiliary device, e.g. of the pre-air-conditioning operation of the device 101 (as mentioned above). The databases 113 , 114 may also be integrated in one single database if suitable.
The time intervals/time differences between the usage of the appliances A, B, C and the departure of the vehicle are recorded as shown in FIG. 4 . This table may be provided in the vehicle scheduler 116 . For each appliance and for each day, a time interval between the time of appliance usage and the vehicle departure is stored. If these data are recorded for a couple of days, the system calculates for each appliance A, B, C the average time interval and the variance of the time intervals and writes these data in additional lines of the table.
Based on the variances, the appliance selector 115 selects the appliance with the lowest variance from the appliances the data of which are stored in the table according to FIG. 4 , wherein appliances with an average time interval below a minimum time interval necessary for e.g. air-conditioning the passenger cabin to a desired temperature can be excluded from this selection. This minimum time may be adapted to the inside temperature of the vehicle and/or the outside temperature. After this selection, the estimated departure time of the vehicle is determined to be the current time plus the average time associated to the selected trigger appliance.
(Second Embodiment)
In alternative embodiments of the invention, estimated departure times may be calculated for multiple appliances used as trigger appliances as described above. The actual estimated departure time can then be calculated using a weighted average of the departure times calculated based on the individual trigger appliances. If e.g. the driver does not use one particular appliance on some particular day, this appliance may be excluded from the average and the estimated departure time values can be suitably adapted.
In the example of FIG. 4 , the appliance A is chosen as the trigger appliance, because it has the lowest variance value. The average interval associated to the appliance A is 59 min. The selection of the trigger appliance is done at regular intervals, e.g. once a day or once a week. If the user uses the vehicle 100 e.g. one time in the morning and one time in the evening, different trigger appliances can be used in the morning and in the evening. The data in the rows of FIG. 4 which are used for calculating the average usage data relate to a particular type of day, e.g. a working day or a holiday. When calculating the averages, working days and holidays are preferably not mixed up.
FIG. 5 shows a processing flow of the procedure from the detection of usage of appliance 111 to starting e.g. a pre-air-conditioning operation of the device 101 . In step 501 , the vehicle scheduler 116 is waiting for input from the appliance monitor 112 . In step 502 , after getting a detection signal from the appliance monitor 112 , the identification number (ID) of the detected appliance 111 is compared with an identification number (ID) of the trigger appliance 111 stored in the trigger condition memory 118 and if the identification numbers are identical, the process forwards to step 503 . If the identification numbers do not correspond to each other, the process returns to previous step 501 .
In step 503 , the vehicle scheduler 116 predicts the vehicle departure time based on the data in the trigger condition memory 118 . In step 504 , based on the predicted departure time of the vehicle the controller 102 determines the starting time of the device 101 using the map 103 . In step 505 , the timer 106 waits until the starting time has come. In step 506 , when the current time has reached the starting time, the timer 106 sends a starting signal to the controller 102 and the controller 102 starts the air conditioning device 101 , using electricity provided from the vehicle charger power supply 117 in the house and not from the battery 104 .
If the charger power supply 117 is not connected to the vehicle 100 , the operation of the auxiliary device 101 is not activated in order to safe battery energy of the vehicle 100 .
Features, components and specific details of the structures of the above-described embodiments may be exchanged or combined to form further embodiments optimized for the respective application. As far as those modifications are apparent for an expert skilled in the art they shall be disclosed implicitly by the above description without specifying explicitly every possible combination.
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The invention relates to a method and a control system for controlling an auxiliary device of a vehicle, wherein the auxiliary device is automatically started at a starting time which is determined based on an estimated departure time of the vehicle. In particular, the invention relates to an air-conditioning device which is automatically started for pre-air-conditioning (PAC) based on an estimate departure time of an electric or hybrid vehicle. The invention enables a precise and flexible automatic determination of an activation time of the auxiliary device, wherein determining a time of usage of at least one home appliance of a user of the vehicle; determining a departure time of the vehicle based on the time of usage of the at least one home appliance; and determining a starting time of said auxiliary device based on the determined departure time of the vehicle are determined.
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FIELD OF THE INVENTION
This invention relates to methods for selective propagation of sweetgum and in particular to propagation of sweetgum by somatic embryogenesis.
BACKGROUND
The sweetgum (Liquidambar styraciflua L.) is a commercially important species particularly for the pulp and paper industry. Unfortunately, current methods for propagation of sweetgum do not provide for clonal production of plants of a proven genetic value on a scale that would be commercially viable.
Since many factors can influence the characteristics of a tree throughout its life, it is desirable to propagate only trees having a proven genotype and which can flourish in a particular region, rather than propagating trees from immature explant material for which the characteristics are as yet unknown. While many methods exist for generating trees which may be successful in a region, no method is known which is capable of producing a high number of trees from a selected individual mature tree. "Mature" means a substantially fully grown tree and not a seedling.
In the field of plant propagation, U.S. Pat. No. 4,818,693 to Stuart et al. describes methods and compositions for generating somatic embryos from immature plant somatic tissue. Stuart et al. start with somatic tissue obtained from the seeds of various plants. While Stuart et al. have been successful in stimulating embryogenesis from immature plant tissue, the methods of Stuart et al. have not succeeded in producing somatic embryos from mature plant tissue. Accordingly, plants generated by the methods of Stuart et al. will not necessarily have the particular genetic code which make the plants successful in a particular environment.
Embryogenesis of tissue cultures from the hypocotyl of sweetgum seedlings was reported in "Embryogenesis in Tissue Cultures of Sweetgum," by H. E. Sommer and C. L. Brown, Forest Science, 26, No. 2, June 1980, pp. 257-260. However, it was found that the yield of embryos was low. Furthermore, since the tissue is obtained from the hypocotyl of the seedlings rather than from mature tissue of plants, the seedlings generated from the tissue do not necessarily have a desirable genotype.
Jorg Jorgensen describes a method for somatic embryogenesis in a paper entitled "Somatic embryogenesis in Aesculus hippocastanum L. by Culture of Filament Callus," Journal of Plant Physiology, 135, 1989, pp. 240-241. In his paper, Jorgensen describes the development of adventitious embryos from filaments of the flowers of 10-100 year old trees. However, the methods described by Jorgensen have been found to be unsuitable for mass production of proembryogenic masses and not suitable for producing somatic embryos of sweetgum.
In a paper entitled "High Frequency Somatic Embryogenesis From Leaf Tissue of Populus ssp.," by Charles H. Michler and Edmund O. Bauer, Plant Science, 77, 1991, pp. 111-118, the authors describe their efforts to produce somatic embryos from a hybrid poplar. According to Michler and Bauer, the somatic embryos which were obtained from a cell suspension culture had an array of aberrant structures in association with embryos with normal morphology. The abnormal morphology included fused cotyledons, fused embryos, shortened hypocotyls and multiple cotyledons and radicles. Based on their results, Michler and Bauer concluded that if embryogenic callus is properly selected, highly morphogenic cultures may be maintained for long periods of time and mature somatic embryos may be obtained. However, the methods of Michler and Bauer are experimental and require additional studies to determine how to control abnormal embryo morphology and developmental synchrony.
The above and other known prior efforts to provide a commercially viable propagation method for somatic embryos from mature plant tissue have been largely unsuccessful. These failures have become a limiting factor in the advancement of the tree cultivation industry and in the art of plant cultivation in general.
It is therefore an object of the invention to provide a method for propagation of woody plant species of a known phenotype.
Another object of the invention is to provide a commercially viable method for propagation of sweetgum from a mature tree with known genetic characteristics.
Yet another object of the invention is to provide a method for cloning plants which can be used to propagate large numbers of individual plants from genetically successful mature plant tissue.
Still another object of the invention is to improve the yield of embryos obtained from mature plant tissue.
Another object of the invention is to increase the yield of somatic embryos from tissue collected from mature sweetgum which may be successfully converted into trees.
SUMMARY OF THE INVENTION
With regard to the foregoing and other objects, the present invention provides a method for producing embryos for propagation of sweetgum. The method comprises collecting inflorescence tissue, preferably male inflorescence tissue, from a mature sweetgum tree. The tissue is first disinfested to substantially eliminate fungal and bacterial propagules from the tissue. Once the tissue is disinfested, selected portions of the tissue are cultured using a cell growth medium containing from about 0.01 to about 2.5 milligrams per liter of N-phenyl-N-1,2,3-thiadiazol-5-ylurea (TDZ).
The present invention provides a method for propagating large numbers of economically important trees on a scale that is suitable for commercialization. An important advantage of the embryogenic methods of the invention over methods which rely on the production of adventitious buds or multiplication of axillary buds from tree cuttings is the potential for very high frequency regeneration of the plants. Virtually unlimited numbers of embryos can be generated from a single explant. In addition, the proembryogenic cultures can be grown in liquid which allows production and handling of thousands of proembryonic masses at one time. Furthermore, the tissue used to propagate the trees may be obtained from mature trees of known genetic value (known phenotype) thereby reducing the risk that the propagated trees will not survive or will not thrive in the environment where they are to be grown. While the present methods are directed particularly to the propagation of sweetgum, it is believed that the methods may be adapted for use in propagating other woody species.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other features and advantages of the invention will be further described in the following detailed description in conjunction with the drawings in which:
FIG. 1 is a photomicrograph of proembryogenic masses arising from an anther cluster;
FIG. 2 is a photomicrograph of proembryogenic masses which have been multiplied according to the methods of this invention;
FIG. 3 is a photomicrograph of a mature somatic embyro obtained from the proembryogenic mass;
FIG. 4 is a photograph of a sweetgum grown from a somatic embryo of the invention;
FIG. 5 is a graphical illustration of the embryogenic response for various embryo induction media; and
FIGS. 6 and 7 are graphical illustrations of the conversion rate of embryos to plants by maturing the embryos on various media.
DETAILED DESCRIPTION OF THE INVENTION
In order to propagate sweetgum according to the methods of the invention, it is preferred to collect male inflorescence tissue from one or more designated sweetgum. It is particularly preferred to collect expanding buds containing staminate inflorescences from the source trees. While the least expanded inflorescences may give the highest embryogenic response, buds at any developmental stage from the beginning of bud expansion up to pollen release may be used. The collected inflorescences from the donor tree preferably have an average length of about 12 mm, which is typically about 35% of the length of the most elongated buds.
After collection of the buds, the bracts are removed and the buds are surface disinfested by methods which substantially eliminate fungal and bacterial propagules from the inflorescence tissue. Initially, the buds are hand washed in cool water using a liquid dish detergent. After washing the buds in water containing detergent, the buds are further disinfested by use of a combination of washing steps under essentially sterile conditions. The washing steps include the use of about 70% (vol./vol.) ethanol for about 30 seconds to about 5 minutes, about 30% (vol./vol.) disinfectant wash solution for about 2 to about 15 minutes, about 10 to about 30% (vol./vol.) sodium hypochlorite solution containing about 5% (vol./vol.) sodium hypochlorite for about 2 to about 15 minutes and sterile water for about 2 to about 30 minutes. It is particularly preferred to include a wash step with 3% (vol./vol.) hydrogen peroxide prior to a final sterile water wash. One or more of the wash steps may include the use of a surfactant to enhance the action of the wash solutions on the bud surfaces. During the washing procedure, outer bud scales from the buds are removed under a microscope, preferably under sterile conditions.
After disinfesting the buds, the clumps of stamens are detached from the axes and the clumps are sliced, preferably in half. While it is preferred to culture cells from the stamens, the axes may also be sliced and cultured in accordance with the procedure of the invention.
The inflorescence parts are cultured on a first plant growth medium. The first plant growth medium is a basal medium of solidified agar containing TDZ and, optionally, 2,4-dichlorophenoxyacetic acid (2,4-D). A preferred basal medium may be selected from a Woody Plant medium (WPM) which is described in "Commercially-feasible micropropagation of mountain laurel, Kalmia latifolia, by use of shoot-tip culture," Proc. Int. Plant Propag. Soc., 30, 1980, pp. 421-427 or a modified Blaydes medium as described in Experiments in Plant Physiology, by F. H. Witham, D. F. Blaydes and R. M. Devlin, Van Nostrand-Reinhold, New York, 1971, 245 pages. Other commercial basal media may also be used in combination with TDZ and, optional, 2,4-D.
The amount of TDZ used in the medium preferably ranges from about 0.01 to about 5 milligrams per liter, most preferably from about 0.01 to about 2.5 milligrams per liter and the amount of 2,4-D in the medium preferably ranges from about 0.01 to about 3 milligrams per liter, most preferably from about 0.01 to about 1.5 milligrams per liter.
The inflorescence parts may be continuously cultured on a single plant growth medium containing TDZ and, optionally, 2,4-D. The parts may also be pulsed during the culturing period by maintaining the parts on basal medium for 1 to 30 days and on a medium containing TDZ for 1 to 30 days over a total period of time of about 6 months.
Within about 6 months, somatic embryos and proembryogenic masses (PEMs) usually appear on the first medium. PEMs are the undifferentiated, densely cytoplasmic cells which arise subsequent to unequal cell division in explant tissue and which have the potential to form somatic embryos. FIG. 1 illustrates the appearance of typical PEMs on an anther cluster magnified about 10 times.
The somatic embryos are transferred to a second growth medium which is comparable to the first medium for additional growth before maturation treatment. Visual inspection of the first medium is used to select the PEMs having the greatest potential for developing into additional somatic embryos. Preferred PEMs have relatively small vacuoles and dense cytoplasm. Cells with relatively large vacuoles are not particularly suitable for the embryogenesis methods of this invention. The selected PEMs are transferred to a liquid medium, preferably on a rotary shaker, where they are cultured in order to increase the total mass of PEMs. FIG. 2 illustrates the appearance of the PEMs after multiplication treatment, magnified about 10 times. The liquid medium for multiplying the PEMs has a composition similar to the first plant growth medium.
After culturing the PEMs for about two months, the PEMs are size fractionated preferably through a stainless steel mesh screen having apertures with a size ranging from about 100 to about 400 microns. After fractionating the PEMs, the PEMs are collected on sterile filter paper and plated onto a growth medium containing activated charcoal and substantially no growth regulators. The concentration of activated charcoal on the growth medium ranges from about 0.25 to about 20 grams per liter and is sufficient to absorb substantially all of the TDZ or 2,4-D which may be in the PEMs which are collected on the filter paper.
Both the somatic embryos which initially formed on the first medium and the somatic embryos which formed from the PEMs on charcoal containing growth medium are subjected to maturation treatment. The maturation treatment includes the use of abscisic acid (ABA), and, optionally, one or more sugars. The abscisic acid is used to inhibit the embryos so that they do not undergo precocious germination. The amount of ABA in the medium is preferably in an amount ranging from about 0.5 to about 3 milligrams per liter. The optional sugars which may be used with the ABA may be selected from glucose, fructose, maltose, sucrose and the like. Particularly preferred sugars are maltose and sucrose. The amount of sugar used with the maturation medium may range from about 20 to about 100 grams per liter of each, most preferably from about 30 to about 90 grams per liter. The entire maturation treatment period typically ranges from about 1 to about 8 weeks or until the somatic embryos have accumulated sufficient energy reserves for later development of the plant. FIG. 3 is an illustration of a mature somatic embryo obtained by the process of this invention (magnified about 20 times). In the photomicrograph, the embryo shown is about 5 millimeters long.
After maturation is substantially complete, the somatic embryos are desiccated under conditions sufficient to reduce the moisture content of the embryos to from about 8 to about 75 percent by weight of the moisture content of the embryos at the end of the maturation period. Desiccating the embryos has been found to be useful for increasing the number of embryos which eventually germinate.
The desiccated embryos are then cold stratified for from about 2 to about 8 weeks at a temperature ranging from about 1° to about 10° C. Cold stratification enhances the somatic embryos' ability to grow shoots. It has been found that by combining desiccation with cold stratification, 90 percent or more of the somatic embryos may be converted to plants. Use of cold stratification alone or desiccation alone results in the formation of plants from only about 30 to about 50 percent of the somatic embryos. A sweetgum derived from a somatic embryo obtained by using the process of this invention is shown in FIG. 4.
An important feature of the invention is the discovery of improved disinfection procedures and cell growth methods which may be used for inducing unequal cell division from mature explant tissue. While not desiring to be bound by theoretical considerations, it is believed that the disinfection procedures using hydrogen peroxide in one of the wash steps in combination with the use of TDZ in a growth medium to induce unequal cell division, significantly increase the yield of embryogenic cells obtained from mature explant tissue. While TDZ is preferred, other cytokinin-like compounds may be used provided they induce unequal cell division in the explant tissue.
In the following example, various features of the invention are illustrated. The examples are not intended to limit the invention in any way.
EXAMPLE
For purposes of disinfesting explant tissue, the buds were first washed in a beaker containing cool water (25° C.) and 3 drops of a liquid dish washing detergent (DAWN detergent). After washing the buds, sterile glassware under a sterile hood was used for the remaining disinfestation steps. The buds were washed as follows for the time indicated:
______________________________________Wash Composition Wash time in minutes______________________________________70% (vol./vol.) ethanol 130% (vol./vol.) BROAD-CIDE 128 disinfectant 5(available from Osceola Supply, Inc. ofTallahassee, FL)30% (vol./vol.) CLOROX bleach 5sterile water 2sterile water 5______________________________________
After the initial wash, the outer bud scales were removed inside of a laminar flow hood under a microscope which had been sterilized with 70% (vol./vol.) isopropyl alcohol. The buds were then washed in accordance with the following procedure:
______________________________________Wash Composition Wash time in minutes______________________________________70% (vol./vol.) ethanol 330% (vol./vol.) BROAD-CIDE 128 disinfectant 510% (vol./vol.) CLOROX bleach 5sterile water 2sterile water 10______________________________________
The remaining bud scales were removed under a sterile hood and with a sterilized microscope and the buds were washed using the following procedure:
______________________________________Wash Composition Wash time in minutes______________________________________3% (vol./vol.) hydrogen peroxide containing 105 drops of TWEEN 20 per 100 milliliters(TWEEN 20 is a wetting agent availablefrom Fisher Scientific of Fairlawn, NJ)sterile water 2______________________________________
The compositions of various growth media used for inducing unequal cell division are contained in the following table:
TABLE 1______________________________________ Amount AmountSample # Component 1 mg/L Component 2 mg/L______________________________________1 .sup. TDZ.sup.1 0.01 -- --2 TDZ 0.05 -- --3 TDZ 0.10 -- --4 TDZ 0.50 -- --5 TDZ 1.00 -- --6 TDZ 0.01 .sup. 2,4-D.sup.2 0.017 TDZ 0.01 2,4-D 0.058 TDZ 0.05 2,4-D 0.019 TDZ 0.05 2,4-D 0.0510 TDZ 0.10 2,4-D 0.0111 TDZ 0.10 2,4-D 0.0512 TDZ 0.50 2,4-D 0.0113 TDZ 0.50 2,4-D 0.0514 TDZ 1.00 2,4-D 0.0115 TDZ 1.00 2,4-D 0.0516 TDZ 0.01 .sup. NAA.sup.3 0.5017 TDZ 0.01 NAA 1.0018 TDZ 0.05 NAA 0.5019 TDZ 0.05 NAA 1.0020 TDZ 0.10 NAA 0.5021 TDZ 0.10 NAA 1.0022 TDZ 0.50 NAA 0.5023 TDZ 0.50 NAA 1.0024 TDZ 1.00 NAA 0.5025 TDZ 1.00 NAA 1.0026 -- -- -- --27 TDZ 1.00 2,4-D 0.5028 TDZ 1.00 2,4-D 0.1029 TDZ 0.50 2,4-D 0.5030 TDZ 0.50 2,4-D 0.1031 TDZ 0.05 2,4-D 0.02532 BA.sup.4 0.25 2,4-D 1.0033 TDZ 0.05 2,4-D 0.1034 TDZ 0.10 2,4-D 0.1035 TDZ 0.05 2,4-D 0.5036 TDZ 0.10 2,4-D 0.50______________________________________ .sup.1 TDZ Nphenyl-N-1,2,3-thiadiazol-5-ylurea .sup.2 2,4D 2,4dichlorophenoxyacetic acid .sup.3 NAA naphthalene acetic acid .sup.4 BA 6benzlyadenine
Of the foregoing samples, a successful media was determined by which media induced any growth whatsoever of somatic embryos from the plant tissue. Of the foregoing, media numbers 1-15, 26-31 and 33-36 were successful for inducing the production of somatic embryos. Media containing TDZ in combination with NAA (Samples 17-25) appeared to be less successful for inducing growth of somatic embryos. The results of the induction of somatic embryos on the media containing the components listed in Table 1 are graphically illustrated in FIG. 5.
In the following table, the compositions of the maturation media which were used are shown.
TABLE 2__________________________________________________________________________ PolyethyleneSample ABA Glycol Maltose SucroseMedia # mg/L μg/125 mL g/L g/125 mL g/L g/125 mL g/L g/125 mL__________________________________________________________________________1 -- -- -- -- 30 3.75 -- --2 -- -- -- -- 60 7.5 -- --3 -- -- -- -- 90 11.25 -- --4 -- -- -- -- -- -- 30 3.755 -- -- -- -- -- -- 60 7.56 -- -- -- -- -- -- 90 11.257 1 125 -- -- 30 3.75 -- --8 2 250 -- -- 30 3.75 -- --9 1 125 -- -- 60 7.5 -- --10 2 250 -- -- 60 7.5 -- --11 1 125 -- -- 90 11.55 -- --12 2 250 -- -- 90 11.25 -- --13 1 125 -- -- -- -- 30 3.7514 1 125 -- -- -- -- 60 7.515 2 250 -- -- -- -- 30 3.7516 2 250 -- -- -- -- 60 7.517 1 125 -- -- -- -- 90 11.2518 2 250 -- -- -- -- 90 11.2519 -- -- 25 3.125 30 3.75 -- --20 -- -- 50 6.25 30 3.75 -- --21 -- -- 25 3.125 60 7.5 -- --22 -- -- 50 6.25 60 7.5 -- --23 -- -- 25 3.125 90 11.25 -- --24 -- -- 50 6.25 90 11.25 -- --25 -- -- 25 3.125 -- -- 30 3.7526 -- -- 50 6.25 -- -- 30 3.7527 -- -- 25 3.125 -- -- 60 7.528 -- -- 50 6.25 -- -- 60 7.529 -- -- 25 3.125 -- -- 90 11.2530 -- -- 50 6.25 -- -- 90 11.2531 1 125 25 3.125 30 3.75 -- --32 1 125 50 6.25 30 3.75 -- --33 1 125 25 3.125 60 7.5 -- --34 1 125 50 6.25 60 7.5 -- --35 1 125 25 3.125 90 11.25 -- --36 1 125 50 6.25 90 11.25 -- --37 1 125 25 3.125 -- -- 30 3.7538 1 125 50 6.25 -- -- 30 3.7539 1 125 25 3.125 -- -- 60 7.540 1 125 50 6.25 -- -- 60 7.541 1 125 25 3.125 -- -- 90 11.2542 1 125 50 6.25 -- -- 90 11.2543 2 250 25 3.125 30 3.75 -- --44 2 250 50 6.25 30 3.75 -- --45 2 250 25 3.125 60 7.5 -- --46 2 250 50 6.25 60 7.5 -- --47 2 250 25 3.125 90 11.25 -- --48 2 250 50 6.25 90 11.25 -- --49 2 250 25 3.125 -- -- 30 3.7550 2 250 50 6.25 -- -- 30 3.7551 2 250 25 3.125 -- -- 60 7.552 2 250 50 6.25 -- -- 60 7.553 2 250 25 3.125 -- -- 90 11.2554 2 250 50 6.25 -- -- 90 11.25__________________________________________________________________________
Of the foregoing samples, media containing maltose and/or sucrose alone or in combination with ABA were found to be useful for maturation treatment. Accordingly, samples 1-18 were found to be the most suitable media for maturation treatment and were successful in terms of conversion from mature embryos into plants. The results of the use of various maturation media as described in Table 2 are illustrated graphically in FIGS. 6 and 7. The percentage conversion of embryos to plants is greatest on maturation media containing maltose or sucrose alone or either one in combination with abscisic acid.
Having described the invention and preferred embodiments thereof, it will be recognized that various modifications, substitutions and rearrangements may be made by those of ordinary skill without departing from the spirit and scope of the appended claims.
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The present invention relates to an improved method for generating somatic embryos from mature plant tissue. The treatment methods of the present invention use a combination of disinfestation procedures and plant growth regulator compositions which induce unequal cell division. After forming and maturing the somatic embryos on suitable growth media, the mature somatic embryos are desiccated and cold stratified resulting in an dramatic increase in the percentage of somatic embryos which may be converted into plants.
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BACKGROUND OF THE INVENTION
[0001] In an apparatus for coupling two storage and/or transport units, for instance in the forms of vessels, containers, tubes and/or the like, for the purpose of a transfer of a product from a first storage and/or transport unit to a second storage and/or transport unit, the first unit has a first closing flap in a first pipe socket at a first end and in an active connection with at least one shaft. The second unit has a second closing flap in a second pipe socket at a second end. With a swivelling device and a safety device, the closing flaps are movable from a closed position wherein the first closing flap tightly closes the first storage and/or transport unit off from the atmosphere at the first end. The second closing flap tightly closes the second storage and/or transport unit off from the atmosphere at the second end and the two closing flaps and/or the two pipe sockets are movable relative to one another into a locked position. The two closing flaps and/or the two pipe sockets are firmly connected to one another. In an open position the closing flaps and/or pipe sockets are firmly connected to one another. At least one flow-through opening for the product is open from the first storage and/or transport unit into the second storage and/or transport unit, and are movable from the open position into the locked position as well as into the closed position.
[0002] Such an apparatus is disclosed, for example, by GB Letters Patent 888,541. Given the known device, the pipe sockets are rotatable relative to one another, whereby a bayonet closure is locked or unlocked by turning the pipe sockets relative to one another and, at the same time, the closing flaps are forced from the closed position into the open position or from the open position into the closed position, so that the locking position coincides with the open position. Such a lock is particularly disadvantageous in that the closing flaps can unintentionally detach from one another while changing from the closed position into the open position or vice versa, also due to the employment of only one bayonet closure. Moreover a cleaning before and/or after a product transfer or a refilling event in the open position is not possible in a locked position in order to avoid contamination of the atmosphere and/or the product to be refilled.
[0003] Further, DE 195 20 409 C1 discloses an apparatus for coupling containers to a blower and extraction device that enables a cleaning of the closing flaps before and/or after a refilling event to be accomplished with the apparatus. A seal is thereby utilized that, given a spacing of the closing flaps of, preferably, less than 15 mm, disadvantageously seals the space situated between the closing flaps, i.e. the impact chamber, off from the outside, with the exception of the regions of the bearing shells thereof. A sealing of the impact chamber from at least a part of the closing flaps is disclosed by DE 299 59 73. An interspace between the closing flaps that is sealed relative to the impact chamber thereby assures that dust that is potentially stirred up due to a scrubbing cannot proceed onto the end face regions, and the extraction cross-section for a cleaning gas, protective atmosphere and/or the like together with particles to be removed is made smaller at the same time, so that the volume stream for the extraction is increased and a greater extraction power is created.
[0004] U.S. Pat. No. 5,690,152 also discloses an apparatus for coupling two containers for bulk goods comprising two pipe sockets as well as a safety device. Each pipe socket comprises a throttle flap seated in an essentially circular seal, whereby one throttle flap can be actively rotated via a swivel drive and, when seated against the second, passive throttle flap, entrains the latter. The safety device comprises at least one pin that is radially movable with reference to the seal and that deforms the seal surrounding the throttle flap in the closed throttle flap position such that an opening of the at least one throttle flap is prevented. Moreover, the apparatus can be equipped with a closure device that is activated when the two containers are docked, so that a release of the pipe sockets from one another during a pouring event is avoided. The safety device and the closure device should thereby be simultaneously activated by an operator via a lever but separately from the swivel drive.
SUMMARY OF THE INVENTION
[0005] It is therefore an object of the present invention to improve an apparatus of the aforementioned type such that the disadvantages of the Prior Art are overcome, particularly such that a structurally simpler and more dependable closing of the closing flaps and/or pipe sockets relative to one another is present before opening the flow-through openings for a refilling event as well as after closing the flow-through openings. A cleaning, particularly in the region of the bearing of the closing flaps, should also be improved.
[0006] This object is achieved by an actuation device via which the safety device can be driven for changing from the closed position into a locked position wherein the two storage and/or transport units are sealed relative to one another and the two closing flaps and/or the two pipe sockets are firmly joined to one another. Then the swivel device can be driven for moving into and subsequently moving out of the open position and, subsequently, the safety device can be driven for changing from the locked position into the closed position.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] [0007]FIG. 1 is a cross-sectional view through an apparatus wherein the closing flaps are in their open position;
[0008] [0008]FIG. 2 is a longitudinal sectional view of the apparatus shown in FIG. 1 wherein the closing flaps are in their cleaning position;
[0009] [0009]FIG. 3 is a perspective view of a closing flap that is employable with an apparatus according to FIGS. 1 and 2; and
[0010] [0010]FIG. 4 is a partial view of a connecting ring that is employable in an apparatus according to FIGS. 1 and 2.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0011] For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the preferred embodiment illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated device, and/or method, and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur now or in the future to one skilled in the art to which the invention relates.
[0012] In the disclosed system and method, it is thereby preferred that the actuation device comprises a gear device with a drive shaft and at least two output shafts, whereby the two output shafts can be addressed by the drive shaft in alternating fashion.
[0013] The safety device has an active connection with, on the one hand, the first output shaft and, on the other hand, with the two pipe sockets. The safety device preferably comprises a connection element between the first pipe socket and the second pipe socket that can be turned around a first axis for locking the two pipe sockets relative to one another or for unlocking them, particularly via at least one bayonet closure.
[0014] The swivel device has an active connection with, on the one hand, the second output shaft and, on the other hand, with at least one of the two closing flaps for turning the closing flaps around a second axis, whereby the swivel device preferably comprises the two semi-axes whereof the first semi-axis is firmly connected to the first closing flap and the second semi-axis is firmly connected to the second closing flap.
[0015] It is preferred that the closing flaps are spaced from one another, at least in regions, between the closed position and the locked position and/or between the open position and the locked position with closing flaps and/or pipe sockets that are at least partly firmly connected to one another in order to limit a cleaning space in a cleaning position that is closed both relative to the atmosphere as well as to the product.
[0016] The connecting element comprises at least one projection or at least one recess and each projection or each recess of the connecting element is in firm engagement with a recess or a projection of the first pipe socket and/or of the second pipe socket in the locked position. Thus each projection or each recess of the connecting element or of the pipe socket or sockets preferably describes or describe an angle relative to the first axis, at least in regions, in order—by turning the connecting element around the first axis—to move the closing flaps away from one another, particularly between the open position and the locked position or toward one another, particularly between the closed position and the locked position.
[0017] It can also be advantageously provided that the first closing flap comprises a first end face with at least one depression and/or elevation, the second closing flap comprises a second end face complementary with the first end face, and the two end faces lie tightly against one another, at least in the open position. Thus in the cleaning position, the end faces are preferably sealed relative to one another in the region of the at least one depression and/or elevation, and the cleaning space is essentially annular.
[0018] The first closing flap comprises at least one first recess at its side lying opposite the first end face and/or the second closing flap comprises at least one second recess at its side lying opposite the second end face for enlarging the flow-through opening or flow-through openings in the open position. The first recess and/or the second recess is or are preferably essentially spherical segment-shaped.
[0019] In the open position, the first closing flap is at least partially in engagement with the second pipe socket and/or the second closing flap is at least partially in engagement with the first pipe socket.
[0020] The first closing flap and/or the second closing flap comprises or comprise at least one partially annular projection, preferably two partially annular projections lying opposite one another, concentrically arranged relative to the second axis for engagement into at least one partially annular recess in the first pipe socket and/or in the second pipe socket.
[0021] Alternatively, the first closing flap and/or the second closing flap comprises or comprise at least one partially annular channel, preferably two partially annular channels lying opposite one another, concentrically arranged relative to the second axis for engagement into at least one partially annular recess in the first pipe socket and/or in the second pipe socket.
[0022] It can also be provided that the second axis resides essentially perpendicular to the first axis.
[0023] The first closing flap is a component part of a passive valve and the second closing flap is a component part of an active valve. The second semi-axis is preferably firmly connected to the second output shaft.
[0024] A cleaning device is provided via which a fluid cleaning agent can be introduced into and removed from the closed cleaning space in the cleaning position.
[0025] A surprising perception is that, given utilization of a single actuation device, a safety device and a swiveling device can be addressed in alternating fashion, i.e. not at the same time, so that, after coupling two containers, pipe sockets of the containers are brought into a locked position and, thus, are firmly locked to one another, so that a parting of the pipe sockets is impossible in the cleaning position. Closing flaps in the pipe sockets insure a tight closure of the of the pipe sockets, and, by subsequently turning the drive shaft from 90° to 180°, the closing flaps are opened via the swiveling device in order to enable a refilling event. By turning the drive shaft back from 180° to 90°, the closing flaps are returned into their closed position, and by turning from 90° to 0°, the pipe sockets are in turn separated from one another. In a partially locked condition of the pipe sockets around the locked position, a region between the pipe sockets and a part of the end faces of the closing flaps, what is referred to as the impact chamber, is implemented for the first time as a cleaning space closed on all sides and that is sealed relative to the outside atmosphere as well as relative to the product space. This is potentially protected against being unintentionally broken open due to the locking of the pipe sockets, and can be advantageously cleaned both before as well as after a refilling event, even with a cleaning fluid, without risk of contamination, whether of the product to be refilled and/or of the atmosphere.
[0026] As can be derived from FIG. 1, an apparatus 1 comprises a first pipe socket 10 at a first container (not shown) that, as soon as the first container is coupled to a second container (not shown), is seated in a second, bipartite pipe socket 100 , 100 ′ of the second container upon interposition of a connecting element or connecting ring 2 . Two valves 20 , 120 are in turn seated in the two pipe sockets, 10 , 100 , 100 ′, whereby the first valve 20 can be passive and the second valve 120 can be active, so that only the active valve 120 can be actively actuated upon utilization of a gear device 300 for opening or closing flow-through openings 200 , 200 ′ from the first container to the second container.
[0027] In the cleaning position shown in FIG. 2, the second pipe socket 100 , 100 ′ embraces the connecting ring 2 that in turns attaches the first pipe socket 10 , so that the pipe sockets 10 , 100 , 100 ′ cannot move relative to one another. For this purpose, the connecting ring 2 is provided with two recesses 3 that lie opposite one another and extend along the inside circumference and into which a respective projection 11 of the first pipe socket 10 can engage, whereby each projection 11 extends at least partially in curved form along the outside circumference of the first pipe socket 10 , as shown in FIG. 4.
[0028] The first pipe socket 10 also comprises two recesses 12 lying opposite one another into which the passive valve 20 engages in the locked position according to FIG. 2. The passive valve 20 in turn comprises a flap 21 having an end face 22 in which a depression 23 is formed and a spherical segment-shaped recess 24 at the side lying opposite the end face 22 . Further, the passive valve 20 is sealed relative to the first pipe socket 10 by means of a closing flap seal 25 and is firmly connected to a first shaft segment comprising a first semi-axis 26 . Finally, the passive valve 20 also comprises two projections 27 for engagement into the recesses 12 .
[0029] In an analogous way, the active valve 120 is seated in the second pipe socket 100 by engagement into two recesses 102 lying opposite one another. The active valve 120 in turn comprises a flap 121 with an end face 122 , from which a projection 127 is salient, and a spherical segment-shaped recess 124 at the side lying opposite the end face 122 . The active valve 120 is also sealed relative to the second pipe socket 100 upon utilization of a closing flap seal 125 . The closing flap 121 of the active valve 120 is firmly connected with a second shaft segment comprising a second semi-axis 126 . Further, projections 127 are offered for engagement into the recesses 102 according to FIG. 2 of the active valve 120 . Moreover, a further closing flap seal 129 is provided between the two closing flaps 21 , 121 in the region of the depression 23 into which the elevation 128 according to FIG. 2 partly engages.
[0030] An alternative active valve 120 ′ is shown in FIG. 3. The active valve 120 ′ thereby comprises a closing flap 121 ′ with a planar end face 122 ′ and a spherical segment-shaped recess 124 ′ at its side lying opposite the end face 122 ′. Further, the closing flap 121 ′ is provided with a semi-axis 126 ′ at one side, two semicircular projections 127 proceeding concentrically to the longitudinal axis thereof.
[0031] According to FIG. 2, the gear device 300 comprises a drive shaft 301 with a disk 302 and a plug 303 that attaches in alternating fashion at a disk 304 with a recess 305 for driving a first output shaft 306 or at a disk 314 with a recess 315 for driving a second output shaft 316 . The first output shaft 306 is also connected to a disk 307 that attaches at the connecting ring 2 for turning the latter, whereas the second output shaft 316 merges into the second semi-axis 126 for actuating the active valve 120 .
[0032] In the cleaning position shown in FIG. 2, finally, a cleaning space 400 closed at all sides is provided between the pipe sockets 10 , 100 as well as the closing flaps 21 , 121 .
[0033] The apparatus whose structure has just been described with reference to the Figures works, for example, in the following way.
[0034] First, the first pipe socket 10 together with the passive valve 20 is inserted into the second pipe socket 100 , 100 ′ as well as the connecting ring 2 until the first pipe socket 10 comes to lie on the second pipe socket 100 in the closed position.
[0035] When the drive shaft 301 is then turned in the direction of the arrow A in FIG. 2, then the plug 303 engages into the recess 305 in the disk 304 in order to transmit the rotary motion onto the first output shaft 306 . Upon utilization of the disk 307 , the first output shaft 306 then compels a rotation of the connecting ring 2 in the direction of the arrow B in FIG. 2, so that the projections 11 of the first pipe socket 10 engage into the corresponding recesses 3 of the connecting ring, which leads to a locking of the pipe sockets 10 , 100 , 100 ; in the fashion of a bayonet closure. Due to the curvature of the projections 11 of the first pipe socket 10 , a lowering of the first pipe socket 10 on the second pipe socket 100 simultaneously occurs given the rotation of the connecting ring 2 in the direction of the arrow B, so that the cleaning space 400 arises, as shown in FIG. 2, which is sealed off both from the atmosphere as well as from the region between the end faces 22 , 122 in the cleaning position sealed by the closing flap seal 129 . The cleaning space 400 can then be flooded with a cleaning gas or a cleaning fluid in order to remove residual contaminants before a refilling event without contaminating the sealed end face regions. After the cleaning, the drive shaft 301 is turned farther upon simultaneous, further locking and further lowering of the first pipe socket 10 relative to the second pipe socket 100 , namely until the end faces 22 , 122 of the closing flaps 21 , 121 lie tightly against one another in the locked position.
[0036] A further rotation of the drive shaft 301 causes the plug 303 to disengage from the recess 305 and engages into the recess 315 of the disk 314 , so that a further rotary motion in the direction of the arrow A is then transmitted onto the second output shaft 316 . Given continued rotation of the drive shaft 301 , a turning of the valves 20 , 120 into the open position shown in FIG. 1 occurs, whereby the projections 27 at the first closing flap 21 simultaneously engage into the recesses 102 of the second pipe socket 100 and the projections 127 at the second closing flap 121 simultaneously engage into the recesses 12 of the first pipe socket. This leads to a locking of the valves 20 , 120 to the pipe sockets 10 , 100 , 100 ′ and makes it impossible to part the valves 20 , 120 from one another in the open position. In the open position, a product (not shown) can flow from the first container into the second container through the flow-through openings 200 , 200 ′ After the end of the product refilling, the drive shaft 301 can be rotated back into its initial position, i.e. opposite the rotational sense A in FIG. 2, whereby, via rotation of the second output shaft 316 , the closing flaps 21 , 121 are again turned into their respective pipe sockets 10 , 100 up into the locked position for sealing the containers relative to one another. The plug 303 then again changes from the recess 315 into the recess 305 in order to turn the connecting ring 2 via the first output shaft 306 and into the cleaning position shown in FIG. 2, wherein a renewed cleaning of the cleaning space 400 is then possible. When the initial position of the drive shaft 301 is reached, finally the interlock is cancelled by releasing the connection between the projections 11 and the recesses 3 , so that the two containers can then be separated from one another in turn.
[0037] In summary, it is therefore to be pointed out that the following stages can be successively run with the apparatus by actuating only the drive shaft 301 :
[0038] 1. Locking the pipe sockets 10 , 100 , 100 ′ relative to one another given simultaneous sealing of the cleaning space 400 ;
[0039] 2. Cleaning the sealed cleaning space 400 in the cleaning position;
[0040] 3. Closing the cleaning space 400 until the locked position is reached;
[0041] 4. Opening the flow-through openings 200 , 200 ′ given simultaneous locking of the closing flaps 21 , 121 to the pipe sockets 10 , 100 ;
[0042] 5. Refilling a product from the first container into the second container;
[0043] 6. Closing the flow-through openings 200 , 200 ′ while simultaneously releasing the lock between the closing flaps 21 , 121 and the pipe sockets 10 , 100 ;
[0044] 7. Opening the cleaning space 400 in the partially locked cleaning position;
[0045] 8. Cleaning the sealed cleaning space 400 ; and
[0046] 9. Complete opening of the cleaning space 400 while simultaneously releasing the lock between the pipe sockets 10 , 100 , 100 ′.
[0047] While a preferred embodiment has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only the preferred embodiment has been shown and described and that all changes and modifications that come within the spirit of the invention both now or in the future are desired to be protected.
[0048] The invention is directed to an apparatus for coupling two storage and/or transport means, for instance in the forms of vessels, containers, tubes and/or the like, for the purpose of a transfer of a product from a first storage and/or transport means having a first closing flap in a first pipe socket at a first end and in an active connection with at least one shaft into a second storage and/or transport means having a second closing flap in a second pipe socket at a second end upon utilization of a swivelling device and a safety device with which the closing flaps are movable from a closed position, wherein the first closing flap tightly closes the first storage and/or transport means off from the atmosphere at the first end, the second closing flap tightly closes the second storage and/or transport means off from the atmosphere at the second end and the two closing flaps and/or the two pipe sockets are movable relative to one another, into a locked position, wherein the two closing flaps and/or the two pipe sockets are firmly connected to one another, as well as into an open position with closing flaps and/or pipe sockets firmly connected to one another wherein at least one flow-through opening for the product is open from the first storage and/or transport means into the second storage and/or transport means, and are movable from the open position into the locked position as well as into the closed position.
[0049] Such an apparatus is disclosed, for example, by GB Letters Patent 888,541.
[0050] Given the known device, the pipe sockets are rotatable relative to one another, whereby a bayonet closure is locked or unlocked by turning the pipe sockets relative to one another and, at the same time, the closing flaps are forced from the closed position into the open position or from the open position into the closed position, so that the locking position coincides with the open position. Such a lock is particularly disadvantageous in that the closing flaps can unintentionally detach from one another while changing from the closed position into the open position or vice versa, also due to the employment of only one bayonet closure. Moreover a cleaning before and/or after a product transfer or, respectively, a refilling event in the open position is not possible in a locked position in order to avoid contamination of the atmosphere and/or the product to be refilled.
[0051] Further, DE 195 20 409 C1 discloses an apparatus for coupling containers to a blower and extraction device that enables a cleaning of the closing flaps before and/or after a refilling event to be accomplished with the apparatus. A seal is thereby utilized that, given a spacing of the closing flaps of, preferably, less than 15 mm, disadvantageously seals the space situated between the closing flaps, i.e. the impact chamber, off from the outside, with the exception of the regions of the bearing shells thereof. A sealing of the impact chamber from at least a part of the closing flaps is disclosed by DE 299 59 73. An interspace between the closing flaps that is sealed relative to the impact chamber thereby assures that dust that is potentially stirred up due to a scrubbing cannot proceed onto said end face regions, and the extraction crossection for a cleaning gas, protective atmosphere and/or the like together with particles to be removed is made smaller at the same time, so that the volume stream for the extraction is increased and a greater extraction power is created.
[0052] It is therefore an object of the present invention to improve an apparatus of the species such that the disadvantages of the Prior Art are overcome, particularly such that a dependable closing of the closing flaps and/or pipe sockets relative to one another is present before opening the flow-through opening(s) for a refilling event as well as after closing the flow-through opening(s). A cleaning, particularly in the region of the bearing of the closing flaps, should also be improved.
[0053] This object is inventively achieved by an actuation device via which the safety device can be driven for changing from the closed position into a locked position wherein the two storage and/or transport means are sealed relative to one another and the two closing flaps and/or the two pipe sockets are firmly joined to one another, then the swivel device can be driven for moving into and subsequently moving out of the open position and, subsequently, the safety device can be driven for changing from the locked position into the closed position.
[0054] It is thereby preferred that the actuation device comprises a gear device with a drive shaft and at least two output shafts, whereby the two output shafts can be addressed [sic] by the drive shaft in alternation.
[0055] Developments of the invention are characterized in that the safety device has an active connection with, on the one hand, the first output shaft and, on the other hand, with the two pipe sockets, whereby the safety device preferably comprises a connection element between the first pipe socket and the second pipe socket that can be turned around a first axis for locking the two pipe sockets relative to one another or for unlocking them, particularly via at least one bayonet closure.
[0056] The invention also proposes that the swivel device has an active connection with, on the one hand, the second output shaft and, on the other hand, with at least one of the two closing flaps for turning the closing flaps around a second axis, whereby the swivel device preferably comprises the two semi-axes whereof the first semi-axis is firmly connected to the first closing flap and the second semi-axis is firmly connected to the second closing flap.
[0057] It is inventively preferred that the closing flaps are spaced from one another, at least in regions, between the closed position and the locked position and/or between the open position and the locked position with closing flaps and/or pipe sockets that are at least partly firmly connected to one another in order to limit a cleaning space in a cleaning position that is closed both relative to the atmosphere as well as to the product.
[0058] The invention also proposes that the connecting element comprises at least one projection or at least one recess and each projection or, respectively, each recess of the connecting element is in firm engagement with a recess or, respectively, a projection of the first pipe socket and/or of the second pipe socket in the locked position, whereby each projection or, respectively, each recess of the connecting element or of the pipe socket or sockets preferably describes or, respectively, describe an angle relative to the first axis, at least in regions, in order—by turning the connecting element around the first axis—to move the closing flaps away from one another, particularly between the open position and the locked position or, respectively, toward one another, particularly between the closed position and the locked position.
[0059] It can also be advantageously provided that the first closing flap comprises a first end face with at least one depression and/or elevation, the second closing flap comprises a second end face complementary with the first end face, and the two end faces lie tightly against one another, at least in the open position, whereby, in the cleaning position, the end faces are preferably sealed relative to one another in the region of the at least one depression and/or elevation, and the cleaning space is essentially annular.
[0060] Developments of the invention are also characterized in that the first closing flap comprises at least one first recess at its side lying opposite the first end face and/or the second closing flap comprises at least one second recess at its side lying opposite the second end face for enlarging the flow-through opening or, respectively, flow-through openings in the open position, whereby the first recess and/or the second recess is or, respectively, are preferably essentially spherical segment-shaped.
[0061] It can also preferably be provided that, in the open position, the first closing flap is at least partially in engagement with the second pipe socket and/or the second closing flap is at least partially in engagement with the first pipe socket.
[0062] It is thereby proposed that the first closing flap and/or the second closing flap comprises or, respectively, comprise at least one partially annular projection, preferably two partially annular projections lying opposite one another, concentrically relative to the second axis for engagement into at least one partially annular recess in the first pipe socket and/or in the second pipe socket.
[0063] Alternatively, it can also be provided the first closing flap and/or the second closing flap comprises or, respectively, comprise at least one partially annular channel, preferably two partially annular channels lying opposite one another, concentrically relative to the second axis for engagement into at least one partially annular recess in the first pipe socket and/or in the second pipe socket.
[0064] It can also be provided that the second axis resides essentially perpendicular to the first axis.
[0065] It can also be inventively provided that the first closing flap is a component part of a passive valve and the second closing flap is a component part of an active valve, whereby the second semi-axis is preferably firmly connected to the second output shaft.
[0066] Finally, inventive developments are proposed that are characterized by a cleaning device via which a fluid cleaning agent can be introduced into and removed from the closed cleaning space in the cleaning position.
[0067] The invention is thus based on the surprising perception that, given utilization of a single actuation device, a safety device and a swiveling device can be addressed in alternation, i.e. not at the same time, so that, after coupling two containers, pipe sockets of the containers and brought into a locked position and, thus, are firmly locked to one another, so that a parting of the pipe sockets is impossible in the cleaning position, whereas closing flaps in the pipe sockets see to a tight closure of the of the pipe sockets, and, by subsequently turning the drive shaft from 90° to 180°, the closing flaps are opened via the swiveling device in order to enable a refilling event. By turning the drive shaft back from 180° to 90°, the closing flaps are returned into their closed position, and, by turning from 90° to 0°, the pipe sockets are in turn separated from one another. In a partially locked condition of the pipe sockets around the locked position, a region between the pipe sockets and a part of the end faces of the closing flaps, what is referred to as the impact chamber, that is implemented for the first time as a cleaning space closed on all sides that is sealed relative to the outside atmosphere as well as relative to the product space and that is potentially protected against being unintentionally broken open due to the locking of the pipe sockets, can be advantageously inventively cleaned both before as well as after a refilling event, even with a cleaning fluid, without risk of contamination, whether of the product to be refilled and/or of the atmosphere.
[0068] Further features and advantages of the invention derive from the following description, wherein exemplary embodiments of the invention are explained on the basis of schematic drawings. Thereby shown are:
[0069] [0069]FIG. 1 a crossectional view through an inventive apparatus wherein the closing flaps are in their open position;
[0070] [0070]FIG. 2 a longitudinal sectional view of the apparatus shown in FIG. 1 wherein the closing flaps are in their cleaning position;
[0071] [0071]FIG. 3 a perspective view of a closing flap that is employable with an apparatus according to FIGS. 1 and 2; and
[0072] [0072]FIG. 4 a partial view of a connecting ring that is employable in an apparatus according to FIGS. 1 and 2.
[0073] As can be derived from FIG. 1, an inventive apparatus 1 comprises a first pipe socket 10 at a first container (not shown) that, as soon as the first container is coupled to a second container (not shown), is seated in a second, bipartite pipe socket 100 , 100 ′ of the second container upon interposition of a connecting element or, respectively, connecting ring 2 . Two valves 20 , 120 are in turn seated in the two pipe sockets, 10 , 100 , 100 ′, whereby the first valve 20 can be passive and the second valve 120 can be active, so that only the active valve 120 can be actively actuated upon utilization of a gear device 300 for opening or, respectively, closing flow-through openings 200 , 200 ′ from the first container to the second container. In the cleaning position shown in FIG. 2, the second pipe socket 100 , 100 ′ embraces the connecting ring 2 that in turns attacks [sic] the first pipe socket 10 , so that the pipe sockets 10 , 100 , 100 ′ cannot move relative to one another. To this end, the connecting ring 2 is provided with two recesses 3 that lie opposite one another and extend along the inside circumference and into which a respective projection 11 of the first pipe socket 10 can engage, whereby each projection 11 extends at least partially is curved form along the outside circumference of the first pipe socket 10 , as shown in FIG. 4.
[0074] The first pipe socket 10 also comprises two recesses 12 lying opposite one another into which the passive valve 20 engages in the locked position according to FIG. 2. The passive valve 20 in turn comprises a flap 21 having an end face 22 in which a depression 23 is formed and a spherical segment-shaped recess 24 at the side lying opposite the end face 22 . Further, the passive valve 20 is sealed relative to the first pipe socket 10 by means of a closing flap seal 25 and is firmly connected to a semi-axis 26 . Finally, the passive valve 20 also comprises two projections 27 for engagement into the recesses 12 .
[0075] In an analogous way, the active valve 120 is seated in the second pipe socket 100 by engagement into two recesses 102 lying opposite one another. The active valve 120 in turn comprises a flap 121 with an end face 122 , from which a projection 127 is salient, and a spherical segment-shaped recess 124 at the side lying opposite the end face 122 . The active valve 120 is also sealed relative to the second pipe socket 100 upon utilization of a closing flap seal 125 . The closing flap 121 of the active valve 120 is firmly fashioned [sic] with a second semi-axis 126 . Further, projections 127 are offered for engagement into the recesses 102 according to FIG. 2 of the active valve 120 . Moreover, a further closing flap seal 129 is provided between the two closing flaps 21 , 121 in the region of the depression 23 into which the elevation 128 according to FIG. 2 partly engages.
[0076] An alternative active valve 120 ′ is shown in FIG. 3. The active valve 120 ′ thereby comprises a closing flap 121 ′ with a planar end face 122 ′ and a spherical segment-shaped recess 124 ′ at its side lying opposite the end face 122 ′. Further, the closing flap 121 ′ is provided with a semi-axis 126 ′ at one side, two semicircular projections 127 proceeding concentrically to the longitudinal axis thereof.
[0077] According to FIG. 2, the gear device 300 comprises a drive shaft 301 with a disk 302 and a plug 303 that attacks in alternation at a disk 304 with a recess 305 for driving a first output shaft 306 or at a disk 314 with a recess 315 for driving a second output shaft 316 . The first output shaft 306 is also connected to a disk 307 that attacks at the connecting ring 2 for turning the latter, whereas the second output shaft 316 merges into the first semi-axis 126 for actuating the active valve 120 .
[0078] In the cleaning position shown in FIG. 2, finally, a cleaning space 400 closed at all sides is provided between the pipe sockets 10 , 100 as well as the closing flaps 21 , 121 .
[0079] The apparatus whose structure has just been described with reference to the Figures works, for example, in the following way.
[0080] First, the first pipe socket 10 together with the passive valve 20 is inserted into the second pipe socket 100 , 100 ′ as well as the connecting ring 2 until the first pipe socket 10 comes to lie on the second pipe socket 100 in the closed position.
[0081] When the drive shaft 301 is then turned in the direction of the arrow A in FIG. 2, then the plug 303 engages into the recess 305 in the disk 304 in order to transmit said rotary motion onto the first output shaft 306 . Upon utilization of the disk 307 , the first output shaft 306 then compels a rotation of the connecting ring 2 in the direction of the arrow B in FIG. 2, so that the projections 11 of the first pipe socket 10 engage into the corresponding recesses 3 of the connecting ring, which leads to a locking of the pipe sockets 10 , 100 , 100 ; in the fashion of a bayonet closure. Due to the curvature of the projections 11 of the first pipe socket 10 , a lowering of the first pipe socket 10 on the second pipe socket 100 simultaneously occurs given the rotation of the connecting ring 2 in the direction of the arrow B, so that the cleaning space 400 arises, this, as shown in FIG. 2, being sealed off both from the atmosphere as well as from the region between the end faces 22 , 122 in the cleaning position sealed by the closing flap seal 129 . The cleaning space 400 can then be flooded with a cleaning gas or a cleaning fluid in order to remove residual contaminants before a refilling event without contaminating the sealed end face regions. After said cleaning, the drive shaft 301 is turned farther upon simultaneous, further locking and further lowering of the first pipe socket 10 relative to the second pipe socket 100 , namely until the end faces 22 , 122 of the closing flaps 21 , 121 lie tightly against one another in the locked position.
[0082] A further rotation of the drive shaft 301 effects that the plug 303 disengages from the recess 305 and engages into the recess 315 of the disk 314 , so that a further rotary motion in the direction of the arrow A is transmitted then onto the second output shaft 316 . Given continued rotation of the drive shaft 301 , a turning of the valves 20 , 120 into the open position shown in FIG. 1 occurs, whereby the projections 27 at the first closing flap 21 simultaneously engage into the recesses 102 of the second pipe socket 100 and the projections 127 at the second closing flap 121 simultaneously engage into the recesses 12 of the first pipe socket, which leads to a locking of the valves 20 , 120 to the pipe sockets 10 , 100 , 100 ′ that makes it impossible to part the valves 20 , 120 from one another in the open position. In the open position, a product (not shown) can flow from the first container into the second container through the flow-through openings 200 , 200 ′
[0083] After the end of the product refilling, the drive shaft 301 can be rotated back into its initial position, i.e. opposite the rotational sense A in FIG. 2, whereby, via rotation of the second output shaft 316 , the closing flaps 21 , 121 are again turned into their respective pipe sockets 10 , 100 up into the locked position for sealing the containers relative to one another. The plug 303 then again changes from the recess 315 into the recess 305 in order to turn the connecting ring 2 via the first output shaft 306 and into the cleaning position shown in FIG. 2, wherein a renewed cleaning of the cleaning space 400 is then possible. When the initial position of the drive shaft 301 is reached, finally, the interlock is cancelled by releasing the connection between the projections 11 and the recesses 3 , so that the two containers can then be separated from one another in turn.
[0084] In summary, it is therefore to be pointed out that the following stages can be successively run with the inventive apparatus by actuating only the drive shaft 301 :
[0085] 1. Locking the pipe sockets 10 , 100 , 100 ′ relative to one another given simultaneous sealing of the cleaning space 400 ;
[0086] 2. Cleaning the sealed cleaning space 400 in the cleaning position;
[0087] 3. Closing the cleaning space 400 until the locked position is reached;
[0088] 4. Opening the flow-through openings 200 , 200 ′ given simultaneous locking of the closing flaps 21 , 121 to the pipe sockets 10 , 100 ;
[0089] 5. Refilling a product from the first container into the second container;
[0090] 6. Closing the flow-through openings 200 , 200 ′ while simultaneously releasing the lock between the closing flaps 21 , 121 and the pipe sockets 10 , 100 ;
[0091] 7. Opening the cleaning space 400 in the partially locked cleaning position;
[0092] 8. Cleaning the sealed cleaning space 400 ; and
[0093] 9. Complete opening of the cleaning space 400 while simultaneously releasing the lock between the pipe sockets 10 , 100 , 100 ′.
[0094] Both individually as well as in any arbitrary combination, the features of the invention disclosed in the above specification, in the claims as well as in the drawings can be critical for realizing the various embodiments of the invention.
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A device couples two storage and/or transport units with a security device. By alternately using a single actuating device, the security device and a pivoting device react in such a way that connecting branches of the units which are coupled are placed in a lock position by the security device and are firmly locked with respect to each other such that it is not possible to separate them. Closing valves in the connecting branches insure that the connecting branches are sealed from each other. By subsequently rotating the drive shaft, it is possible to open the closing valves using the pivoting device in order to enable a transfer process to occur. By rotating the drive shaft back, the closing valves are re-closed. Also by rotating the drive shaft, the connecting branches can be separated from each other.
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CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation application of and claims priority to U.S. application Ser. No. 11/492,725, filed on Jul. 25, 2006, which claims the benefit under 35 U.S.C. §119(e)(1) of U.S. Provisional Patent Application Ser. No. 60/706,883, filed Aug. 10, 2005, the contents of which are hereby incorporated by reference.
FIELD OF THE INVENTION
[0002] The invention relates to an imaging system, in particular a projection objective of a projection exposure apparatus used in the field of microlithography. The invention relates in particular to a projection objective which even with an off-axis image field allows the use of highly refractive crystal materials while keeping the negative effect of birefringence on image quality within limits.
BACKGROUND
[0003] In current state-of-the-art microlithography objectives, particularly in immersion objectives with a numerical aperture value (NA) of more than 1.0, there is a growing need to use materials of a high refractive index. In this context, a refractive index is considered high if, at the given wavelength, it exceeds the value for the refractive index of quartz, which has a refractive index of about 1.56 at a wavelength of 193 nm. A number of materials are known whose refractive indices at DUV- and VUV wavelengths (<250 nm) are larger than 1.6, for example magnesium spinel with a refractive index of about 1.87 at a wavelength of 193 nm, or magnesium oxide which has a refractive index of about 2.0 at 193 nm.
[0004] When using these materials as lens elements, the problem presents itself that due to their cubic crystallographic structure, they exhibit a degree of intrinsic birefringence that increases as the wavelength becomes shorter. For example, measurements of the retardation due to intrinsic birefringence in magnesium spinel at a wavelength of 193 nm produced a value of 52 nm/cm, while the retardation due to intrinsic birefringence in magnesium oxide at a wavelength of 193 nm was estimated to be about 72 nm/cm. Depending on the design-related conditions in the image field, a retardation of this magnitude can lead to lateral ray deflections that are three to five times as large as today's critical structure widths of about 80-100 nm.
[0005] As a means to reduce the negative effect on the optical image caused by intrinsic birefringence in fluoride crystal lenses, it is known for example from US 2004/0105170 A1 and WO 02/093209 A2 to arrange fluoride crystal lenses of the same crystallographic cut in rotated orientations relative to each other (a concept known as “clocking”) and, in addition, to combine several groups of such arrangements with different crystallographic cuts (for example groups of 100-lenses and groups of 111-lenses) with each other.
[0006] Although the negative effect of the intrinsic birefringence can be compensated by this method to a certain extent even in the aforementioned highly refractive cubic materials, a further problem presents itself in that the compensation achieved with the aforementioned “clocking” is incomplete in the case where the respective “compensation paths” are different (i.e., the respective path lengths which the rays that enter into interference with each other traverse in the mutually rotated parts of the same crystallographic cut). This is the case in particular in a projection objective that produces an off-axis image field. Off-axis fields of this kind are present in particular in catadioptric projection objectives with geometric beam-splitting of the type disclosed, e.g., in WO 2004/019128.
[0007] The aforementioned problem with different compensation path lengths in different materials used for the compensation of birefringence can also occur in materials with natural birefringence, for example if materials with opposite (positive/negative) signs in their birefringence are combined with each other for compensation, as described in WO 2005/059645, or with the “clocking” of materials with natural birefringence.
SUMMARY OF THE INVENTION
[0008] In certain embodiments, an imaging system, in particular a projection objective for a microlithographic projection exposure apparatus, is provided wherein the imaging system allows the use of highly refractive crystal materials even with an off-axis image field, while keeping the negative effect of birefringence on image quality within limits.
[0009] According to one aspect, an imaging system, in particular a projection objective of a microlithographic projection exposure apparatus which has an optical axis and produces an image field that is extra-axial relative to the optical axis, includes the following:
a first optical element which produces a first distribution of the retardation in a plane that extends perpendicular to the optical axis; and at least one second optical element which produces a second distribution of the retardation in a plane that extends perpendicular to the optical axis, which second distribution compensates at least partially for the first distribution of the retardation; wherein each the first and the second optical element are of a configuration that is not rotationally symmetric to the optical axis.
[0013] According to another aspect, an imaging system having an optical axis and being capable of producing an image field which is extra-axial relative to the optical axis is provided. The imaging system includes a first optical element which, during use of the imaging system, causes a first distribution of retardation in a plane that lies perpendicular to the optical axis. The imaging system also includes at least one second optical element which, during use of the imaging system, causes a second distribution of retardation in a plane that lies perpendicular to the optical axis. The second distribution of retardation at least partially compensates the first distribution of retardation, and the first and the second optical elements are not designed with rotational symmetry relative to the optical axis.
[0014] According a further aspect, a microlithographic projection exposure apparatus having a projection objective as described above is provided.
[0015] According to an additional aspect, a method for the microlithographic production of micro-structured components is provided. The method includes preparing a substrate on which at least one coating of a light-sensitive material is deposited, and preparing a mask which has structures of which images are to be formed. The method also includes preparing a microlithographic projection exposure apparatus as described above, and projecting at least a part of the mask onto an area of the coating by means of the projection exposure apparatus.
[0016] According to yet another aspect, a micro-structured component which is produced according to method described above is provided.
[0017] The term “retardation” means the difference between the optical path lengths of two orthogonal (i.e., mutually perpendicular) states of linear polarization.
[0018] The term “optical axis” as used in the present application means a straight line or a sequence of straight line segments that runs through the centers of curvature of the rotationally symmetric optical components.
[0019] The concept of “elements” in the sense of the present application includes the possibility that, e.g., the at least two elements are seamlessly joined to each other, specifically by the technique of wringing, so that they form one lens together.
[0020] Due to the fact that in accordance with the invention, the first and the second optical element are not of a rotationally symmetric design relative to the optical axis, i.e., by consciously giving up the principle of rotational symmetry in regard to these elements, it becomes possible to take the extra-axial position of the image field into account and in particular to create the possibility for equal compensation paths in the respective elements with the different distributions of the retardation.
[0021] In a preferred embodiment, the first optical element and the second optical element are made of a cubic crystal material, so that their respective retardations are obtained as a result of intrinsic birefringence.
[0022] In a further preferred embodiment, the first optical element and the second optical element are made of an optically uniaxial crystal material.
[0023] In a preferred embodiment, the retardation caused by the second optical element has the opposite sign of the retardation caused by the first optical element.
[0024] In a further embodiment, the first optical element and the second optical element are of the same crystallographic cut and are rotated relative to each other about the optical axis.
[0025] In a preferred embodiment, the extra-axial image field is mirror-symmetric relative to a plane of symmetry, and the first and/or the second optical element is mirror-symmetric relative to the same plane of symmetry. Preferably in this embodiment, the first and/or the second optical element have as their only symmetry a mirror-symmetry relative to the plane of symmetry.
[0026] In a preferred embodiment, the following condition is met for at least one ray that falls on the center of the image field: n 1 ×d 1 ≈n 2 ×d 2 , wherein n i (i=1, 2) stands for the respective refractive indices and d i (i=1, 2) indicates the geometrical path lengths covered by this ray in the first and the second optical element, respectively. Consequently for this particular ray, it is assured that the optical path lengths in the two partial elements (which at least partially compensate each other in regard to birefringence), in other words the compensation paths for this ray, are equal, so that the reduction of the retardation achieved thereby represents the maximum for the given combination of elements.
[0027] If the foregoing condition is met for the largest possible number of rays falling on the center of the image field, one achieves the result that for the rays falling outside of the center of the image field, a possible difference between the compensation paths will at least not be overly large. In other words, according to the invention the optimization of the compensation paths takes place for the rays that fall on the center of the image field, in order to achieve on average as good a compromise as possible in regard to obtaining compensation paths of equal length for the rays that fall outside the center of the image field.
[0028] In the ideal case, the condition n 1 ×d 1 ≈n 2 ×d 2 stated above is met for all of the rays that fall on the center of the image field, and in any case preferably for rays arriving from the largest possible angular range. In a preferred embodiment, the condition n 1 ×d 1 ≈n 2 ×d 2 is met for at least two rays falling on the center of the image field, wherein the angle between the two rays is at least 40°, preferably at least 50°, with even higher preference at least 60°, and with still higher preference at least 70°.
[0029] In a preferred embodiment the first element and the second element each have a crystallographic (111)-cut and are arranged with a rotation of 60°±k×120° (wherein k=0, 1, 2, . . . ) relative to each other about the element axis. In this way, by combining the two elements in a principally known manner, one achieves (due to the three-fold symmetry in the distribution of the retardation as a function of the azimuth angle, which applies to the case of the crystallographic 111-cut) an azimuthally symmetric distribution of the retardation as well as a reduction of the maximum values obtained for the retardation.
[0030] A preferred embodiment further contains a third and a fourth optical element, each with a crystallographic (100)-cut and arranged with a rotation about the element axis of 45°±l×90° relative to the other (wherein l=1, 2, . . . ). In this way, by combining the third and fourth optical elements, one achieves likewise (due to the four-fold symmetry in the distribution of the retardation as a function of the azimuth angle, which applies to the case of the crystallographic 100-cut) an azimuthally symmetric distribution of the retardation as well as a reduction of the maximum values obtained for the retardation. With preference, the third and fourth optical elements, too, are not configured with rotational symmetry relative to the optical axis. In a preferred embodiment, the condition n 3 ×d 3 ≈n 4 ×d 4 is met for at least one ray falling on the center of the image field, wherein n i (i=3, 4) stands for the respective refractive indices and d i (i=3, 4) indicates the geometrical path lengths covered by this ray in the third and the fourth optical element, respectively.
[0031] In a preferred embodiment at least two, but preferably all, of these optical elements are joined by wringing in such a way that they form a lens together.
[0032] With preference, the lens has a rotationally symmetric shape in relation to the optical axis and can in particular be a planar-convex lens.
[0033] In a preferred embodiment, the lens is a last refractive lens on the image side of the imaging system.
[0034] In a preferred embodiment, each of the optical elements is shaped like a shell whose convex-curved side faces towards the object side.
[0035] In a preferred embodiment, a liquid is arranged between at least two of the optical elements, wherein the two elements and the liquid have substantially the same refractive index. In this way, the requirements on the planarity of the contact surfaces between the optical elements can be less stringent, because due to the matching refractive index of the liquid, discontinuities of the refractive index and ray path deflections associated with them can be avoided at least to a far-reaching extent. The liquid needs to be selected appropriately, depending on the refractive index of the optical elements, an example being perhydro fluorene (with n=1.6862 at 193 nm) when the refractive indices of the optical elements are in the range from about 1.6 to 1.7 at a wavelength of 193 nm.
[0036] Further preferred embodiments relate to the selection of the cubic crystal material. This selection is made preferably with the aim of a further reduction of the effect of intrinsic birefringence, and expressly allowing for the fact that even when the extra-axial image field is taken into consideration as called for by the invention, a complete compensation of the retardation can lastly not be realized, because the equality of the compensation paths can as a rule not be achieved for all of the rays.
[0037] In a preferred embodiment, the cubic crystal material has at a given working wavelength a refractive index n of such a magnitude that the difference (n-NA) between the refractive index n and the numerical aperture NA does not exceed 0.2.
[0038] This takes into consideration that the effect of intrinsic birefringence does not increase linearly as the wavelength becomes shorter, but rather begins with a gradual increase and then rises dramatically with a further decrease in the wavelength. This non-linearity is all the more pronounced, the nearer the working wavelength gets to the absorption edge (in the UV range) for the respective material. Thus, according to the preferred embodiment, the possibilities for choosing materials with the highest possible refractive indices are not fully exploited, but the refractive index is selected just as high as required (and not higher) in order to still be able to geometrically guide projection light even under the maximally occurring ray angles through the projection objective so that the rays produce an image. At the same time, according to the invention one takes advantage of the more moderate requirement on the magnitude of the refractive index in order to select a crystal material whose absorption edge lies farther in the UV range, so that as a result the intrinsic birefringence in the range of the working wavelength becomes even smaller, or has increased less strongly, than would be the case in a material whose absorption edge lies at a higher wavelength.
[0039] Under the preferred embodiment, for example with a numerical aperture of NA=1.5, one therefore consciously foregoes the option of selecting the crystal materials of the highest possible refractive indices despite the fact that materials are available which are transparent at typical working wavelengths of 193 nm and have high refractive indices of, e.g., n=1.87 (magnesium spinel). Rather, one uses materials in which the refractive index n is farther removed from the (lower) value of the image-side numerical aperture of the imaging system, but is still just sufficient in order to direct the projection light even under the maximally occurring ray angles through the imaging system so that the light rays produce an image.
[0040] Preferably, the difference (n-NA) between the refractive index n of the optical element and the numerical aperture NA of the imaging system is in the range from 0.05 to 0.20, with higher preference in the range from 0.05 to 0.15, and with special preference in the range from 0.05 to 0.10. As stated above, due to the upper limit of the refractive index one achieves a limitation of the intrinsic birefringence, while a limit on the overall lens volume of the projection objective is achieved due to the lower limit of the refractive index.
[0041] Further criteria that should preferably be met by the materials used in accordance with the invention include adequate stability to withstand atmospheric humidity and UV light, a high degree of hardness, a material that is good to work with in optical manufacturing processes and, as much as possible, a non-toxic composition.
[0042] In a preferred embodiment the cubic crystal material includes an oxide for which a sufficient transmissivity was obtained together with a comparatively high refractive index.
[0043] In a preferred embodiment the cubic crystal material includes sapphire (Al 2 O 3 ) and a potassium- or calcium oxide among its components.
[0044] In particular, the cubic crystal material preferably includes at least one material selected from the group that includes 7Al 2 O 3 .12CaO, Al 2 O 3 .K 2 O, Al 2 O 3 .3CaO, Al 2 O 3 .SiO 2 KO, Al 2 O 3 .SiO 2 .2K and Al 2 O 3 .3CaO6H 2 O.
[0045] The share of sapphire (Al 2 O 3 ) in the foregoing materials causes a widening of the band gap or a shift of the absorption edge into the UV range while raising the refractive index at the same time, so that refractive index-lowering further components supplement the mixed crystal, which leads to the aforementioned lowering of the intrinsic birefringence.
[0046] In a further preferred embodiment, the cubic crystal material includes calcium, sodium and silicon oxide. In particular, the cubic crystal material preferably contains at least one material from the group that includes CaNa 2 SiO 4 and CaNa 4 Si 3 O 9 .
[0047] In a further preferred embodiment, the cubic crystal material contains at least one material from the group that includes Sr(NO 3 ) 2 , MgONa 2 O.SiO 2 and Ca(NO 3 ) 2 .
[0048] In a further preferred embodiment, a further optical element which is substantially planar-parallel is placed on the light exit surface of the planar-convex lens.
[0049] With this type of a component structure for the optical element, one gains the advantage of a particularly effective correction of the spherical aberration which in the case of high aperture values typically represents the largest contribution to the image aberrations that have to be dealt with. If the ray pattern is telecentric in the area of the optical element, the planar-parallel partial element provides in particular an advantageous way to achieve a correction of the spherical aberration that is uniform over the image field.
[0050] In contrast to the aforementioned composite structure made up of the first and the second optical element (particularly in the case of the planar-convex lens), if the substantially planar-parallel optical element is composed of mutually rotated portions of the same crystallographic cut, the compensation paths for the portions are substantially equal, so that insofar an effective correction of the intrinsic birefringence can occur by way of the clocking concept. Consequently, it is advantageous to consider arranging in the planar-parallel optical element a second material with a higher refractive index than the material in the first portion. In particular, this higher refractive index can also lie outside the aforementioned interval from the numerical aperture. In a preferred embodiment, the second material is therefore selected from the group consisting of magnesium spinel (MgAl 2 O 4 ), yttrium aluminum garnet (Y 3 Al 5 O 12 ), MgO and scandium aluminum garnet (Sc 3 Al 5 O 12 ).
[0051] According to a preferred embodiment, the working wavelength is less than 250 nm, preferably less than 200 nm, and with even higher preference less than 160 nm.
[0052] According to a preferred embodiment, the imaging system is a catadioptric projection objective with at least two concave mirrors which produces at least two intermediate images.
[0053] The invention further relates to a microlithographic projection exposure apparatus, a method of producing microlithographic components, and a micro-structured component.
[0054] Further embodiments of the invention are presented in the description as well as in the subordinate claims.
[0055] The invention is explained hereinafter in more detail with reference to examples that are illustrated in the attached drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0056] In the drawings:
[0057] FIGS. 1 to 3 are schematic representations of different preferred embodiments which serve to explain the design structure of an optical element in an imaging system according to the invention; and
[0058] FIG. 4 is a schematic illustration of the principal design structure of a microlithographic projection exposure apparatus which can have a projection objective according to the invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0059] In a merely schematic manner, FIG. 1 shows the design structure of an optical element 100 in an imaging system according to the invention in accordance with a first preferred embodiment. With preference, the optical element 100 is in particular the last lens on the image side in a microlithographic projection objective whose principal design structure remains to be explained hereinafter in the context of FIG. 4 .
[0060] Preferably, the imaging system is a catadioptric projection objective in which according to FIG. 1 (in a merely schematic representation that is not true to scale) an off-axis image field “F” (i.e., lying outside of the optical axis “OA”) is produced in an image plane “Im”. According to FIG. 1 , the last optical element on the image side is a planar-convex lens 100 which in regard to its optical outside surface is rotationally symmetric relative to the optical axis OA. However, as shown schematically in FIG. 1 , the planar-convex lens is composed of elements 110 and 120 which are not rotationally symmetric themselves relative to the optical axis OA. The first element 110 in FIG. 1 is shaped like a shell in such a way that its concave light-exit surface on the image side is in direct contact with the corresponding light-entry surface of the second element 120 .
[0061] The elements 110 and 120 in the illustrated example are made of cubic crystal material, preferably of the same material with the same crystallographic cut. According to a first embodiment, both elements can consist of magnesium spinel (MgAl 2 O 4 ) with (111)-orientation of the crystallographic cut. However, the elements 110 and 120 are arranged with a rotation of about 60° relative to each other, so that—with equal compensation path lengths in the two elements—one achieves an azimuthally symmetric distribution of the retardation as well as a reduction of the maximum values of the retardation.
[0062] The invention is not limited to using cubic crystal materials in the elements 110 , 120 (nor in the elements according to the embodiments described hereinafter). For example, the first optical element and the second optical element in a further embodiment can be made of an optically uniaxial crystal material. Suitable materials of the optically uniaxial type are for example lanthanum fluoride (LaF 3 ), sapphire (Al 2 O 3 ) or beryllium oxide (BeO), also referred to as bromellite. The materials can also be selected particularly in such a way that the retardation caused by the second optical element has the opposite sign of the retardation caused by the first optical element. For example, the first optical element can be formed of sapphire (Al 2 O 3 ) with the refractive indices n o =1.7681 and n e =1.7600 at λ=589.3 nm, i.e., Δn=n e −n o =−0.0081, and the second optical element can be formed of beryllium oxide (bromellite, BeO) with the refractive indices n o =1.7186 and n e =1.7343 at λ=589.3 nm, i.e., Δn=n e −n o =+0.0157, so that the birefringence has opposite signs in the two elements, which allows a mutual compensation and a reduction of the maximum values for the retardation to be achieved.
[0063] In order to achieve at least to a large extent an agreement between the compensation path lengths, the (asymmetric) arrangement of the two elements 110 , 120 according to FIG. 1 is made exactly in such a way that an agreement of the compensation path lengths is achieved for the rays falling on the center of the image field F. Two such rays “A” and “B” are shown as examples, with the distances covered by the rays in the elements 110 , 120 identified, respectively, as a 1 , a 2 and b 1 , b 2 . To achieve the desired equality of the compensation path lengths, the distances a 1 , a 2 and b 1 , b 2 are selected so that the respective optical path lengths n i ×a i (i=1, 2) and n i ×b i (i=1, 2) for the two rays A and B turn out the same in the first element 110 and in the second element 120 . Since according to this embodiment the refractive indices are the same in the elements 110 and 120 , the foregoing condition is reduced to a 1 =a 2 and b 1 =b 2 .
[0064] A further preferred embodiment will be explained with the help of FIG. 2 .
[0065] According to FIG. 2 , the last optical element on the image side is a planar-convex lens 100 which in regard to its optical outside surface is rotationally symmetric to the optical axis OA but is composed of four elements 210 , 220 , 230 and 240 which are not rotationally symmetric themselves relative to the optical axis OA. The first element 210 , the second element 220 and the third element 230 in FIG. 2 are each shaped like a shell in such a way that a concave light-exit surface is in direct contact with the corresponding light-entry surface of the next following element.
[0066] The elements 210 and 220 are analogous to the elements 110 and 220 in regard to crystallographic cut and orientation. In particular, both can consist of magnesium spinel (MgAl 2 O 4 ) in (111)-cut orientation arranged with a rotation of about 60° relative to each other. The elements 230 and 240 , likewise, can consist for example of magnesium spinel (MgAl 2 O 4 ), however in (100)-cut orientation arranged with a rotation of about 45° relative to each other.
[0067] Two rays “A” and “B” are again shown as examples. The distances traveled by the rays in the elements 210 , 220 , 230 and 240 in FIG. 2 are identified, respectively, as a 1 to a 4 and b 1 to b 4 . To achieve the desired equality of the compensation path lengths, the distances a 1 to a 4 and b 1 to b 4 are selected so that the respective optical path lengths n i ×a i (i=1, 2) and n i ×b i (i=1, 2) for the two rays A and B turn out the same in the element 210 and in the element 220 . The optical path lengths n i ×a i (i=3, 4) and n i ×b i (i=3, 4) in the elements 230 and 240 , respectively, are likewise made equal. Since according to this embodiment the refractive indices in the elements are the same, the foregoing conditions are reduced to a 1 =a 2 , a 3 =a 4 , and b 1 =b 2 , b 3 =b 4 , respectively. Preferably, the further condition a 1 /a 3 =b 1 /b 3 ≈2/3 is also being met.
[0068] The invention is not limited to the arrangement of the optical elements that is shown in FIG. 1 or FIG. 2 . Rather, the invention is meant to encompass any arrangement of at least two elements that are not formed in a rotationally symmetric shape relative to the optical axis in an imaging system with an extra-axial image field, wherein each of the two elements is made of a cubic or optically uniaxial crystalline material and the at least two elements are arranged so that the distributions of the retardation that are obtained due to intrinsic or natural birefringence will compensate each other at least partially.
[0069] According to further embodiments, the refractive index of the cubic crystal material is of such a magnitude that the difference (n-NA) between the refractive index n and the numerical aperture NA of the imaging system does not exceed 0.2.
[0070] If one assumes for example a numerical aperture of NA=1.5 for the projection objective, it is therefore preferred for the refractive index n of the cubic crystalline material of the first partial element to be maximally n=1.7.
[0071] A list of materials that are particularly preferred according to the invention is presented in the following Table 1, wherein the refractive index n d at the wavelength λ=589 nm for each of the crystal materials is shown in column 2. It should be noted that the refractive index at a typical working wavelength of λ=193 nm is typically larger by about 0.1.
[0000]
TABLE 1
Refractive Index n d
Material
(at λ = 589 nm)
7Al 2 O 3 •12CaO
1.608
Al 2 O 3 •K 2 O
1.603
Al 2 O 3 •3CaO
1.701
Al 2 O 3 •SiO 2 KO
1.540
Al 2 O 3 •SiO 2 •2K
Al 2 O 3 •3CaO6H 2 O
1.604
CaNa 2 SiO 4
1.60
CaNa 4 Si 3 O 9
1.571
Sr(NO 3 ) 2
1.5667
MgONa 2 O•SiO 2
1.523
Ca(NO 3 ) 2
1.595
[0072] According to a further preferred embodiment of an optical element 300 as illustrated in FIG. 3 , a further optical element 320 of substantially planar-parallel shape is placed on the light-exit surface of a planar-convex lens 310 with the configuration described in the context of FIGS. 1 and 2 . Preferably, the element 320 is joined by wringing to the light-exit surface of the planar-convex lens 310 .
[0073] FIG. 3 also schematically shows how the planar-parallel optical element 320 is composed of a total of four parts in the form of planar-parallel plates 321 , 322 , 323 and 324 which preferably consist of the same cubic crystal material, for example magnesium spinel. The first plate 321 and the second plate 322 are of a crystallographic (111)-cut and are arranged with a rotation of 60° relative to each other (or generally 60°±k×120°, with k=0, 1, 2, . . . ) about the element axis (which in FIG. 3 coincides with the optical axis OA). The third plate 323 and the fourth plate 324 are of a crystallographic (100)-cut and are rotated relative to each other by 45° relative to each other (or generally 45°+l×90°, with l=0, 1, 2, . . . ) about the element axis.
[0074] FIG. 4 illustrates a projection exposure apparatus 400 with an illumination device 401 and a projection objective 402 . The projection objective 402 includes a lens arrangement 403 with an aperture stop AP, wherein an optical axis OA is defined by the schematically indicated lens arrangement 403 . Arranged between the illumination device 401 and the projection objective 402 is a mask 404 which is held in the light path by means of a mask holder 405 . Masks 404 of this type which are used in microlithography have a structure with details in the micrometer to nanometer range, an image of which is projected by means of the projection objective 402 into the image plane IP, reduced for example by a factor of 4 or 5. A light-sensitive substrate 406 , specifically a wafer, which is positioned by a substrate holder 407 , is held in the image plane IP. The minimum dimensions of structures that can still be resolved depend on the wavelength λ of the light that is used for the illumination and also on the image-side numerical aperture of the projection objective 402 , wherein the ultimately achievable resolution of the projection exposure apparatus 400 increases with shorter wavelengths λ of the illumination device 401 and a larger numerical aperture on the image side of the projection objective 402 .
[0075] The projection objective 402 is configured as an imaging system in accordance with the present invention. In a merely schematic manner, FIG. 4 indicates in broken lines a possible approximate position of an optical element 300 according to the invention, wherein according to a preferred embodiment the optical element 300 in this example is the last optical element on the image side of the projection objective 402 and therefore arranged in the area of relatively large aperture angles. The optical element 300 can be of a design structure as discussed in the context of FIGS. 1 to 3 .
[0076] Even though the invention has been described through the presentation of specific embodiments, those skilled in the pertinent art will recognize numerous possibilities for variations and alternative embodiments, for example by combining and/or exchanging features of individual embodiments. Accordingly, it will be understood that such variations and alternative embodiments are considered as being included in the present invention and that the scope of the invention is limited only by the attached patent claims and their equivalents.
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Imaging systems, in particular a projection objectives of a microlithographic projection exposure apparatus, are provided. The imaging systems can have an optical axis and produce an image field which is extra-axial relative to the optical axis. The imaging systems can include a first optical element which causes a first distribution of the retardation in a plane that lies perpendicular to the optical axis, and at least one second optical element which causes a second distribution of the retardation in a plane that lies perpendicular to the optical axis. The second distribution of the retardation can at least partially compensate the first distribution of the retardation. The first and the second optical elements can be designed without rotational symmetry relative to the optical axis.
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This patent is a continuation of U.S. patent application Ser. No. 09/062,881, filed on Apr. 20, 1998, now U.S. Pat. No. 6,147,168 which is a continuation-in-part of U.S. patent application Ser. No. 08/964,733, filed on Nov. 5, 1997, now U.S. Pat. No. 5,859,150, which is a continuation-in-part of Ser. No. 08/744,289, filed on Nov. 6, 1996, now U.S. Pat. No. 5,698,213, which is a continuation-in-part of Ser. No. 08/611,119, filed Mar. 5, 1996, now U.S. Pat. No. 5,607,687, which is a continuation-in-part of Ser. No. 08/554,011, filed Nov. 6, 1995, now abandoned, which is a continuation-in-part of Ser. No. 08/399,308, filed Mar. 6, 1995, now U.S. Pat. No. 5,464,929 all assigned to Ethicon, Inc.
FIELD OF THE INVENTION
The present invention relates to a bioabsorbable copolymeric material and blends thereof and more particularly to absorbable surgical products made from such copolymers and blends thereof.
BACKGROUND OF THE INVENTION
Since Carothers early work in the 1920s and 1930s, aromatic polyesters particularly poly(ethylene terephthalate) have become the most commercial important polyesters. The usefulness of these polymers is intimately linked to the stiffening action of the p-phenylene group in the polymer chain. The presence of the p-phenylene group in the backbone of the polymer chain leads to high melting points and good mechanical properties especially for fibers, films and some molded products. In fact poly(ethylene terephthalate) has become the polymer of choice for many common consumer products, such as one and two liter soft drink containers.
Several related polyester resins have been described in U.S. Pat. Nos. 4,440,922, 4,552,948 and 4,963,641 which seek to improve upon the properties of poly(ethylene terephthalate) by replacing terephthalic acid with other related dicarboxylic acids which contain phenylene groups. These polymers are generally designed to reduce the gas permeability of aromatic polyesters.
Other aromatic polyesters have also been developed for specialty applications such as radiation stable bioabsorbable materials. U.S. Pat. Nos. 4,510,295, 4,546,152 and 4,689,424 describe radiation sterilizable aromatic polyesters which can be used to make sutures and the like. These polymers like, poly(ethylene terephthalate), have phenylene groups in the backbone of the polymers.
However, less research has been reported on aliphatic polyesters. After Carothers initial work on polyesters, aliphatic polyesters were generally ignored because it was believed that these materials had low melting points and high solubilities. The only aliphatic polyesters that have been extensively studied are polylactones such as polylactide, polyglycolide, poly(p-dioxanone) and polycaprolactone. These aliphatic polylactones have been used primarily for bioabsorbable surgical sutures and surgical devices such as staples. Although polylactones have proven to be useful in many applications they do not meet all the needs of the medical community. For example films of polylactones do not readily transmit water vapor, therefore, are not ideally suited for use as bandages where the transmission of water vapor would be desired.
Recently there has been renewed interest in non-lactone aliphatic polyesters. U.S. Pat. No. 5,349,028 describes the formation of very simple aliphatic polyesters based on the reaction of a diol with a dicarboxylic acid to form prepolymer chains that are then coupled together. These polyesters are being promoted for use in fibers and molded articles because these polyesters are biodegradable after they are buried such as in a landfill. However, these materials are not disclosed as being suitable for use in surgical devices.
To address the deficiencies in the polymers described in the prior art we invented a new class of polymers which are disclosed in U.S. Pat. Nos. 5,464,929; 5,595,751; 5,597,579; 5,607,687; 5,618,552; 5,620,698; 5,645,850; 5,648,088; 5,698,213; and 5,700,583 (all of which are hereby incorporated by reference). This new class of polymers is hydrolyzable and suitable for a variety of uses including medical applications. To further broaden the possible uses for these polymers we are disclosing and claiming herein copolymers of the polyoxaamides (which includes polyoxaesteramides) and blends thereof with other polymers with modified hydrolysis profiles. These polymers may be used in industrial and consumer applications where biodegradable polymers are desirable, as well as, in medical devices.
SUMMARY OF THE INVENTION
We have discovered a new class of synthetic copolymeric materials and blends thereof that may be used to produce surgical devices such as molded devices, drug delivery matrices, coatings, lubricants and the like. The invention also contemplates a process for producing the copolymers and blends. The copolymers and blends of the present invention comprise a polyoxaester copolymer having a first divalent repeating unit of formula IA:
[—O—C(O)—R 30 —C(O)—] IA
a second divalent repeating unit of the formula IB:
[—O—C(O)—C(R 1 )(R 2 )—O—R 3 —O—C(R′ 1 )(R′ 2 )—C(O)—] IB
and a third repeating unit selected from the group of formulas consisting of:
[—O—R 4 —] A , II
[—O—R 5 —C(O)] B , III
([—O—R 5 —C(O)] P —O—) L G XI
and combinations thereof, wherein R 30 is an alkylene, arylene, arylalkylene, substituted alkylene, substituted arylene and substituted alkylarylene provided that R 30 cannot be —[C(R 1 )(R 2 )] 1-2 —O—(R 3 )—O—[C(R′ 1 )(R′ 2 ) 1-2 —; R 1 , R′ 1 , R 2 and R′ 2 are independently hydrogen or an alkyl group containing 1 to 8 carbon atoms; R 3 is an alkylene unit containing from 2 to 12 carbon atoms or is an oxyalkylene group of the following formula:
—[(CH 2 ) C —O—] D —(CH 2 ) E — IV
wherein C is an integer in the range of from 2 to about 5, D is an integer in the range of from about 0 to about 2,000, and E is an integer in the range of from about 2 to about 5, except when D is zero, in which case E will be an integer from 2 to 12; R 4 is an alkylene unit containing from 2 to 8 carbon atoms; A is an integer in the range of from 1 to 2,000; R 5 is selected from the group consisting of —C(R 6 )—(R 7 )—, —(CH 2 ) 3 —O—, —CH 2 —CH 2 —O—CH 2 —, —CR 8 H—CH 2 —, —(CH 2 ) 5 —, —(CH 2 ) F —O—C(O)— and —(CH 2 ) F —C(O)—CH 2 —; R 6 and R 7 are independently hydrogen or an alkyl containing from 1 to 8 carbon atoms; R 8 is hydrogen or methyl; F is an integer in the range of from 2 to 6; B is an integer in the range of from 1 to n such that the number average molecular weight of formula III is less than about 200,000, preferably less than about 100,000 and most preferably less than 40,000; P is an integer in the range of from 1 to m such that the number average molecular weight of formula XI is less than about 1,000,000, preferably less than about 200,000 and most preferably less than 40,000; G represents the residue minus from 1 to L hydrogen atoms from the hydroxyl group of an alcohol previously containing from 1 to about 200 hydroxyl groups; and L is an integer from about 1 to about 200.
Additionally, the present invention describes devices, coatings, drug release matrices, adhesives, sealants and prepolymers.
DETAILED DESCRIPTION OF THE INVENTION
The aliphatic polyoxaesters of the present invention are the reaction product of 1) a dicarboxylic acid; 2) an aliphatic polyoxycarboxylic acid; and 3) at least one of the following compounds: a diol (or polydiol), a lactone (or lactone oligomer), a coupling agent or combination thereof. For the purpose of this application aliphatic shall mean an organic compound having a straight, branched, or cyclic arrangement of carbon atoms (i.e. alkanes, olefins, cycloalkanes, cycloolefins and alkynes).
Suitable non-dioxycarboxylic acids may be polyfunctional for use in the present invention generally have the following formula:
HOOC—R 30 —COOH VA
wherein R 30 is an alkylene, arylene, arylalkylene, substituted alkylene, substituted arylene and substituted alkylarylene provided that R 30 cannot be [—C(R 1 )(R 2 )] 1-2 —O—(R 3 )—O—[C(R′ 1 )(R′ 2 )] 1-2 —; and these non-dioxycarboxylic acids may be substituted with heteroatoms or groups. The non-dioxycarboxylic acids of the present invention are generally polycarboxylic acids and more preferably dicarboxylic acids. However, monocarboxylic acids may be used as end caps for the copolymer that are formed. If carboxylic acids are used that have more than two carboxylic acid groups the resulting copolymers may form star shapes or crosslinked matrices depending on the concentration of the carboxylic acids having more than two carboxylic acid groups. Representative unsaturated aliphatic dicarboxylic acids include, but are not limited to, those selected from the group consisting of maleic acid, fumaric acid and combinations thereof. Representative saturated aliphatic dicarboxylic acids include, but are not limited to, those selected from the group consisting of oxalic acid, malonic acid (propanedioic), succinic (butanedioic), glutaric (pentanedioic), adipic (hexadioic), pimelic (heptanedioic), octanedioic, nonanedioic, decanedoic, undecanedioic, dodecanedioic, hendecanedioic, tetradecanedioic, pentadecanedioic, hexadecanedioic, heptadecandioic, octadecanedioic, nonadecanedioic, eicosanedioic acid and combinations thereof. Representative aromatic dicarboxylic acids include, but are not limited to, those selected from the group consisting of phthalic acid, isophthalic acid, terephthalic acid, phenylenediglycolic acid, caboxymethoxybenzoic acid and combinations thereof.
Suitable aliphatic alpha-oxycarboxylic acids for use in the present invention generally have the following formula:
HO—C(O)—C(R 1 )(R 2 )—O—R 3 —O—C(R′ 1 )(R′ 2 )—C(O)—OH V
wherein R 1 , R′ 1 , R 2 and R′ 2 are independently selected from the group consisting of hydrogen or an alkyl group containing from 1 to 8 carbon atoms and R 3 is an alkylene containing from 2 to 12 carbon atoms or is an oxyalkylene group of the following formula:
—[(CH 2 ) C —O—] D —(CH 2 ) E — IV
wherein C is an integer in the range of from about 2 to about 5, D is an integer in the range of from about 0 to about 2,000 and preferably from 0 to 12, and E is an integer in the range of from about 2 to about 5. These aliphatic alpha-hydroxycarboxylic acids may be formed by reacting a diol or polydiol with an alpha-halocarboxylic acid such bromoacetic acid or chloroacetic acid under suitable conditions.
Suitable diols or polydiols for use in the present invention are diol or diol repeating units with up to 8 carbon atoms having the formula:
H[—(O—R 4 —) A ]OH VI
wherein R is an alkylene unit containing from 2 to 8 methylene units; A is an integer in the range of from 1 to about 2,000 and preferably from 1 to about 1000. Examples of suitable diols include diols selected from the group consisting of 1,2-ethanediol (ethylene glycol), 1,2-propanediol (propylene glycol), 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,3-cyclopentanediol, 1,6-hexanediol, 1,4-cyclohexanediol, 1,8-octanediol and combinations thereof. Examples of preferred polydiols include polydiols selected from the group consisting of polyethylene glycol (H[—O—CH 2 —CH 2 —] A OH) and polypropylene glycol (H[—O—CH 2 —CH(CH 3 )—] A OH).
The ratio of non-dioxycarboxylic acid to aliphatic oxydicarboxylic acid should be in the range of from about 1:99 to about 99:1. The rate of hydrolysis can be controlled, in part, by changing the ratio of the non-oxadiacid-based moeties to those of the oxadiacid-based moeties. As the concentration of the non-oxadiacid-based moeties increases, the hydrolysis rate will be lower. Besides taking into account the hydrophilic/hydrophobic nature of the reactants, one can also exert control through the steric nature of the alcohol, amine, and amino alcohol groups employed. Thus the hydrolysis rate of an ester based on a secondary alcohol is slower than that of an ester based on a primary alcohol group. The relative concentration of aromatic moieties will effect the hydroylsis rate. Additionally, the presence of aromatic moieties will help resist the loss of properties that may occur during sterilization by gamma irradiation. Higher concentrations of such groups will be better for cobalt sterilizable products.
The copolymer produced by reacting the non-dioxydicarboxylic acid and aliphatic dioxycarboxylic acid with the diols discussed above should provide a copolymer generally having the formula:
[O—C(O)—R 30 —C(O)—(O—R′ 4 ) A′ —] N′ [—O—C(O)—C(R 1 )(R 2 )—O—R 3 —O—C(R′ 1 )(R′ 2 )—C(O)—(O—R 4 ) A —] N VII
wherein R 1 , R 2 , R′ 1 , R′ 2 , R 3 , R 4 and A are as described above; R′ 4 and A′ have the same definitions respectively as R 4 and A but vary independently therefrom; N and N′ are integers in the range of from about 1 to about 10,000 and preferably is in the range of from about 10 to about 1,000 and most preferably in the range of from about 50 to about 200.
Suitable lactone monomers that may be used in the present invention generally have the formula:
These lactone monomers may be polymerized to provide copolymers of the following general structures:
H[—O—R 5 —C(O)—] B OH IX
(H[—O—R 5 —C(O)] P —O—) L G X
wherein R 5 is selected from the group consisting of —C(R 6 )(R 7 )—, —(CH 2 ) 3 —O—, —CH 2 —CH 2 —O—CH 2 —, —CR 8 H—CH 2 —, —(CH 2 ) 5 —, —(CH 2 ) F —O—C(O)— and —(CH 2 ) F —C(O)—CH 2 —; R 6 and R 7 are independently hydrogen or an alkyl containing from 1 to 8 carbon atoms; Re is hydrogen or methyl; F is an integer of from about 2 to 6; B is an integer in the range of from 1 to n such that the number average molecular weight of formula IX is less than about 200,000, preferably less than 100,000, and most preferably less than 40,000; P is an integer in the range of from 1 to m such that the number average molecular weight of formula X is less than 1,000,000 about, preferably less than about 200,000 and most preferably less than 40,000; G represents the residue minus from 1 to L hydrogen atoms from the hydroxyl groups of an alcohol previously containing from 1 to about 200 hydroxyl groups; and L is an integer from about 1 to about 200. In one embodiment G will be the residue of a dihydroxy alcohol minus both hydroxyl groups. In another embodiment of the present invention G may be a polymer containing pendent hydroxyl groups (including polysaccharides). Suitable lactone-derived repeating units may be generated from the following monomers include but are not limited to lactone monomers selected from the group consisting of glycolide, d-lactide, 1-lactide, meso-lactide, ε-caprolactone, p-dioxanone, trimethylene carbonate, 1,4-dioxepan-2-one, 1,5-dioxepan-2-one and combinations thereof.
The copolymer formed by reacting the above described diol (or polydiol) VI, the nonoxydicarboxylic acids and aliphatic polyoxycarboxylic acid V may also be copolymerized in a condensation polymerization with the lactone polymers IX described above to form a polymer generally of the formula:
[(—C(O)—R 30 —C(O)—(O—R′ 4 )′ A —O)′ S (—C(O)—C(R 1 )(R 2 )—O—R 3 —O—C(R′ 1 )(R′ 2 )—C(O)—(O—R 4 ) A —O) S (C(O)—R 5 —O) B ] W XII
or
[(—C(O)—R 30 —C(O)—(O—R′ 4 )′ A —O)′ S (—C(O)—C(R 1 )(R 2 )—O—R 3 —O—C(R′ 1 )(R′ 2 )—C(O)—(O—R 4 ) A —O) S ([—O—R 5 —C(O)] P —O—) L G] W XIII
wherein S and S′ are integers in the range of from about 1 to about 10,000 and preferably from about 1 to about 1,000 and W is an integer in the range of from about 1 to about 1,000. These copolymers may be made in the form of random copolymers or block copolymers. To the diols, nonoxydicarboxylic acids, aliphatic polyoxycarboxylic acids and lactone monomers described above there may be added a coupling agent selected from the group consisting of polyfunctional (i.e. trifunctional or tetrafunctional) polyols, oxycarboxylic acids, and polybasic carboxylic acids (or acid anhydrides thereof). The addition of the coupling agents causes the branching of long chains, which can impart desirable properties in the molten state to the polyester prepolymer. Examples of suitable polyfunctional coupling agents include trimethylol propane, glycerin, pentaerythritol, malic acid, citric acid, tartaric acid, trimesic acid, propane tricarboxylic acid, cyclopentane tetracarboxylic anhydride and combinations thereof.
The amount of coupling agent to be added before gelation occurs is a function of the type of coupling agent used and the polymerization conditions of the polyoxaester or molecular weight of the prepolymer to which it is added. Generally in the range of from about 0.1 to about 10 mole percent of a trifunctional or a tetrafunctional coupling agent may be added based on the moles of polyoxaester copolymers present or anticipated from the synthesis.
The polymerization of the polyoxaester copolymer is preferably performed under melt polycondensation conditions in the presence of an organometallic catalyst at elevated temperatures. The organometallic catalyst is preferably a tin-based catalyst e.g. stannous octoate. The catalyst will preferably be present in the mixture at a mole ratio of diol, nonoxycarboxylic acid, aliphatic polyoxycarboxylic acid and optionally lactone monomer to catalyst will be in the range of from about 15,000 to 80,000/1. The reaction is preferably performed at a temperature no less than about 120° C. under reduced pressure. Higher polymerization temperatures may lead to further increases in the molecular weight of the copolymer, which may be desirable for numerous applications. The exact reaction conditions chosen will depend on numerous factors, including the properties of the copolymer desired, the viscosity of the reaction mixture, and the glass transition temperature and softening temperature of the polymer. The preferred reaction conditions of temperature, time and pressure can be readily determined by assessing these and other factors.
Generally, the reaction mixture will be maintained at about 220° C. The polymerization reaction can be allowed to proceed at this temperature until the desired molecular weight and percent conversion is achieved for the copolymer, which will typically take about 15 minutes to 24 hours. Increasing the reaction temperature generally decreases the reaction time needed to achieve a particular molecular weight.
In another embodiment, copolymers of polyoxaester can be prepared by forming a polyoxaester prepolymer polymerized under melt polycondensation conditions, then adding at least one lactone monomer or lactone prepolymer. The mixture would then be subjected to the desired conditions of temperature and time to copolymerize the prepolymer with the lactone monomers.
The molecular weight of the prepolymer as well as its composition can be varied depending on the desired characteristic, which the prepolymer is to impart to the copolymer. However, it is preferred that the polyoxaester prepolymers from which the copolymer is prepared have a molecular weight that provides an inherent viscosity between about 0.2 to about 2.0 deciliters per gram (dl/g) as measured in a 0.1 g/dl solution of hexafluoroisopropanol at 25° C. Those skilled in the art will recognize that the polyoxaester prepolymers described herein can also be made from mixtures of more than one diol or dioxycarboxylic acid.
One of the beneficial properties of the polyoxaester made by the process of this invention is that the ester linkages are hydrolytically unstable, and therefore the copolymer is bioabsorbable because it readily breaks down into small segments when exposed to moist bodily tissue. By controlling the ratio of oxycarboxylic acid to nonoxycarboxylic acid the hydrolysis rate of the resulting copolymer may be tailored to the desired end product and end use.
These aliphatic polyoxaesters described herein and those described in U.S. Pat. Nos. 5,464,929; 5,595,751; 5,597,579; 5,607,687; 5,618,552; 5,620,698; 5,645,850; 5,648,088; 5,698,213; and 5,700,583 may be blended together with other homopolymers, copolymers and graft copolymers to impart new properties to the material formed by the blend. The other polymers which the aliphatic polyoxaesters may be blended with include but are not limited to homopolymer and copolymer of lactone type polymers with the repeating units described by Formula VIII, aliphatic polyurethanes, polyether polyurethanes, polyester polyurethanes polyethylene copolymers (such as ethylene-vinyl acetate copolymers and ethylene ethyl acrylate copolymers), polyamides, polyvinyl alcohols, poly(ethylene oxide), polypropylene oxide, polyethylene glycol, polypropylene glycol, polytetramethylene oxide, polyvinyl pyrrolidone, polyacrylamide, poly(hydroxy ethyl acrylate), poly(hydroxyethyl methacrylate), absorbable polyoxalates, absorbable polyanhydrides. The copolymers (i.e. containing two or more repeating units) including random, block and segmented copolymers. Suitable lactone-derived repeating units may be generated from the following monomers include but are not limited to lactone monomers selected from the group consisting of glycolide, d-lactide, 1-lactide, meso-lactide, ε-caprolactone, p-dioxanone, trimethylene carbonate, 1,4-dioxepan-2-one, 1,5-dioxepan-2-one and combinations thereof. The blends may contain about 1 weight percent to about 99 weight percent of the aliphatic polyoxaesters.
For some applications it may be desirable to add additional ingredients such as stabilizers, antioxidants radiopacifiers, fillers or the like.
The copolymers and blends of this invention can be melt processed by numerous methods to prepare a vast array of useful devices. These copolymers and blends can be injection or compression molded to make implantable medical and surgical devices, especially wound closure devices. The preferred wound closure devices are surgical clips, staples and sutures.
Alternatively, the copolymers and blends can be extruded to prepare fibers. The filaments thus produced may be fabricated into sutures or ligatures, attached to surgical needles, packaged, and sterilized by known techniques. The copolymers of the present invention may be spun as multifilament yarn and woven or knitted to form sponges or gauze, (or non-woven sheets may be prepared) or used in conjunction with other molded compressive structures as prosthetic devices within the body of a human or animal where it is desirable that the structure have high tensile strength and desirable levels of compliance and/or ductility. Useful embodiments include tubes, including branched tubes, for artery, vein or intestinal repair, nerve splicing, tendon splicing, sheets for typing up: and supporting damaged surface abrasions, particularly major abrasions, or areas where the skin and underlying tissues are damaged or surgically removed.
Additionally, the copolymers and blends can be processed to form films, felts, foams and gels which, when sterilized, are useful as skin coverings or adhesion prevention devices. Another alternative processing technique for the copolymer and blends of this invention includes solvent casting, particularly for those applications where a drug delivery matrix is desired.
In more detail, the surgical and medical uses of the filaments, films, and molded articles of the present invention include, but are not necessarily limited to:
Knitted products, woven or non-woven, and molded products including:
a. burn dressings
b. hernia patches
c. medicated dressings
d. fascial substitutes
e. gauze, fabric, sheet, felt or sponge for liver hemostasis
f. gauze bandages
g. arterial graft or substitutes
h. bandages for skin surfaces
i. suture knot clip
j. orthopedic pins, clamps, screws, and plates
k. clips (e.g., for vena cava)
l. staples
m. hooks, buttons, and snaps
n. bone substitutes (e.g., mandible prosthesis)
o. intrauterine devices (e.g., spermicidal devices)
p. draining or testing tubes or capillaries
q. surgical instruments
r. vascular implants or supports
s. vertebral discs
t. extracorporeal tubing for kidney and heart-lung machines
u. artificial skin
v. catheters (including, but not limited to, the catheters described in U.S. Pat. No. 4,883,699 which is hereby incorporated by reference)
w. scaffoldings for tissue engineering applications
x. adhesion prevention devices (felts, films, foams and liquids).
In another embodiment, the polyoxaester copolymers (including prepolymers and suitable crosslinked copolymers and blends) is used to coat a surface of a surgical article to enhance the lubricity of the coated surface (or for drug delivery purposes as described hereinafter). The copolymers may be applied as a coating using conventional techniques. For example, the copolymers may be solubilized in a dilute solution of a volatile organic solvent, e.g. acetone, methanol, ethyl acetate or toluene, and then the article can be immersed in the solution to coat its surface. Once the surface is coated, the surgical article can be removed from the solution where it can be dried at an elevated temperature until the solvent and any residual reactants are removed.
For use in coating applications the copolymers and blends should exhibit an inherent viscosity (initial IV in the case of crosslinkable copolymers), as measured in a 0.1 gram per deciliter (g/dl) of hexafluoroisopropanol (HFIP), between about 0.05 to about 2.0 dl/g, preferably about 0.10 to about 0.80 dl/g. If the inherent viscosity were less than about 0.05 dl/g (final IV for crosslinked copolymers), then the copolymer blend may not have the integrity necessary for the preparation of films or coatings for the surfaces of various surgical and medical articles. On the other hand, although it is possible to use copolymer blends with an inherent viscosity greater than about 2.0 dl/g, initial IV for crosslinkable copolymers), it may be exceedingly difficult to do so.
Although it is contemplated that numerous surgical articles (including but not limited to endoscopic instruments) can be coated with the copolymers and blends of this invention to improve the surface properties of the article, the preferred surgical articles are surgical sutures and needles. The most preferred surgical article is a suture, most preferably attached to a needle. Preferably, the suture is a synthetic absorbable suture. These sutures are derived, for example, from homopolymers and copolymers of lactone monomers such as glycolide, lactide, ε-caprolactone, 1,4-dioxanone, and trimethylene carbonate. The preferred suture is a braided multifilament suture composed of polyglycolide or poly(glycolide-co-lactide).
The amount of coating to be applied on the surface of a braided suture can be readily determined empirically, and will depend on the particular copolymer or blend and suture chosen. Ideally, the amount of coating applied to the surface of the suture may range from about 0.5 to about 30 percent of the weight of the coated suture, more preferably from about 1.0 to about 20 weight percent, most preferably from 1 to about 5 weight percent. If the amount of coating on the suture were greater than about 30 weight percent, then it may increase the risk that the coating may flake off when the suture is passed through tissue.
Sutures coated with the copolymers and blends of this invention are desirable because they have a more slippery feel, thus making it easier for the surgeon to slide a knot down the suture to the site of surgical trauma. In addition, the suture is more pliable, and therefore is easier for the surgeon to manipulate during use. These advantages are exhibited in comparison to sutures which do not have their surfaces coated with the copolymers and blends of this invention.
In another embodiment of the present invention when the article is a surgical needle, the amount of coating applied to the surface of the article is an amount which creates a layer with a thickness ranging preferably between about 2 to about 20 microns on the needle, more preferably about 4 to about 8 microns. If the amount of coating on the needle were such that the thickness of the coating layer was greater than about 20 microns, or if the thickness was less than about 2 microns, then the desired performance of the needle as it is passed through tissue may not be achieved.
In yet another embodiment of the present invention, the copolymers and blends can be used as a pharmaceutical carrier in a drug delivery matrix. To form this matrix the copolymers and blends would be mixed with a therapeutic agent to form the matrix. The variety of different therapeutic agents which can be used in conjunction with the polyoxaesters of the invention is vast. In general, therapeutic agents which may be administered via the pharmaceutical compositions of the invention include, without limitation: antiinfectives such as antibiotics and antiviral agents; analgesics and analgesic combinations; anorexics; antihelmintics; antiarthritics; antiasthmatic agents; anticonvulsants; antidepressants; antidiuretic agents; antidiarrheals; antihistamines; antiinflammatory agents; antimigraine preparations; antinauseants; antineoplastics; antiparkinsonism drugs; antipruritics; antipsychotics; antipyretics, antispasmodics; anticholinergics; sympathomimetics; xanthine derivatives; cardiovascular preparations including calcium channel blockers and beta-blockers such as pindolol and antiarrhythmics; antihypertensii,es; diuretics; vasodilators including general coronary, peripheral and cerebral; central nervous system stimulants; cough and cold preparations, including decongestants; hormones such as estradiol and other steroids, including corticosteroids; hypnotics; immunosuppressives; muscle relaxants; parasympatholytics; psychostimulants; sedatives; and tranquilizers; and naturally derived or genetically engineered proteins, polysaccharides, glycoproteins, or lipoproteins.
The drug delivery matrix may be administered in any suitable dosage form such as oral, parenteral, a subcutaneously as an implant, vaginally or as a suppository. Matrix formulations containing the copolymers and blends may be formulated by mixing one or more therapeutic agents with the polyoxaester. The therapeutic agent may be present as a liquid, a finely divided solid, or any other appropriate physical form. Typically, but optionally, the matrix will include one or more additives, e.g., nontoxic auxiliary substances such as diluents, carriers, excipients, stabilizers or the like. Other suitable additives may be formulated with the polyoxaester and pharmaceutically active agent or compound, however, if water is to be used it should be added immediately before administration.
The amount of therapeutic agent will be dependent upon the particular drug employed and medical condition being treated. Typically, the amount of drug represents about 0.001% to about 70%, more typically about 0.001% to about 50%, most typically about 0.001% to about 20% by weight of the matrix.
The quantity and type of copolymer blends incorporated into the parenteral will vary depending on the release profile desired and the amount of drug employed. The product may contain blends of copolymers having different molecular weights to provide the desired release profile or consistency to a given formulation.
The copolymers and blends, upon contact with body fluids including blood or the like, undergoes gradual degradation (mainly through hydrolysis) with concomitant release of the dispersed drug for a sustained or extended period (as compared to the release from an isotonic saline solution). This can result in prolonged delivery (over, say 1 to 2,000 hours, preferably 2 to 800 hours) of effective amounts (say, 0.0001 mg/kg/hour to 10 mg/kg/hour) of the drug. This dosage form can be administered as is necessary depending on the subject being treated, the severity of the affliction, the judgment of the prescribing physician, and the like.
Individual formulations of drugs and copolymer or blends may be tested in appropriate in vitro and in vivo models to achieve the desired drug release profiles. For example, a drug could be formulated with a copolymer or blend and orally administered to an animal. The drug release profile could then be monitored by appropriate means such as, by taking blood samples at specific times and assaying the samples for drug concentration. Following this or similar procedures, those skilled in the art will be able to formulate a variety of formulations.
The copolymers, and blends of the present invention can be crosslinked to affect mechanical properties. Crosslinking may either be chemically or physical. Chemically crosslinked copolymer chains are connected by covalent bonds, which can be formed by reactive groups contained on the copolymers, the addition of crosslinking enhancers and/or irradiation (such as gamma-irradiation). Physical crosslinking on the other hand connects the copolymer chains through non-covalent bonds such as van der Waals interactions hydrogen bonding or hydrophobic interactions. In particular, crosslinking can be used to control the water swellability of said invention.
The polymerizable regions are preferably polymerizable by photoinitiation by free radical generation, most preferably in the visible or long wavelength ultraviolet radiation. The preferred polymerizable regions are acrylates, diacrylates, oligoacrylates, methacrylates, dimethacrylates, oligomethoacrylates, or other biologically acceptable photopolymerizable groups.
Other initiation chemistries may be used besides photoinitiation. These include, for example, water and amine initiation schemes with isocyanate or isothiocyanate containing macromers used as the polymerizable regions.
Useful photoinitiaors are those which can be used to initiate by free radical generation polymerization of the macromers without cytotoxicity and within a short time frame, minutes at most and most preferably seconds. Preferred dyes as initiators of choice for long wavelength ultraviolet (LWUV) or visible light initiation are ethyl eosin, 2,2-dimethoxy-2-phenyl acetophenone, other acetophenone derivatives, and camphorquinone. Polymerization and/or crosslinking may be initiated among macromers by a light activated free-radical polymerization initiator such as 2,2-dimethoxy-2-phenyl acetophenone, other acetophenone derivatives, and camphorquinone. In other cases, polymerization and/or crosslinking are initiated among macromers by a light-activated free-radical polymerization initiator such as 2,2-dimethoxy-2-phenylacetophenone or a combination of ethyl eosin (10- 4 to 10- 2 M) and triethanol amine (0.001 to 0.1M), for example.
The choice of the photoinitiator is largely dependent on the photopolymerizable regions. Although we do not wish to be limited by scientific theory, it is believed the macromer includes at least one carbon—carbon double bond, light absorption by the dye can cause the dye to assume a triplet state, the triplet state subsequently reacting with the amine to form a free radical which initiates polymerization. Preferred dyes for use with these materials include eosin dye and initiators such as 2,2-dimethyl-2-phenylacetophenone, 2-methoxy-2-phenylacetophenone, and camphorquinone. Using such initiators, copolymers may be polymerized in situ by LWUV light or by laser light of about 514 nm, for example.
Initiation of polymerization (and in some cases crosslinking) is accomplished by irradiation with light at a wavelength of between about 200-700 nm, most preferably in the long wavelength ultraviolet range or visible range, 320 nm or higher, most preferably about 514 nm or 365 nm.
There are several photooxidizable and photoreductible dyes that may be used to initiate polymerization. These include acridine dyes, for example, acriblarine; thiazine dyes, for example, thionine; xanthine dyes, for example, rose bengal; and phenazine dyes, for example, methylene blue. These are used with cocatalysis such as amines, for example, triethanolamine; sulphur compounds, for example, RSO 2 R 1 ; heterocycles, for example, imidazole; enolates; organometallics; and other compounds, such as N-phenyl glycine. Other initiators include camphorquinones and acetophenone derivatives.
Thermal polymerization (and optionally crosslinking) initiator systems may also be used. Thermal initiators may be selected to allow polymerization to be initiated at a desired temperature. At times it may be desired to use a high temperature to initiate polymerization such as during a molding process. For many medical uses it will be desired to use systems that will initiate free radical polymerization, at physiological temperatures include, for example, potassium persulfate, with or without tetramethyl ethylenediamine; benzoylperoxide, with or without triethanolamine; and ammonium persulfate with sodium bisulfite.
The copolymers (which may be crosslinked) and blends (hereinafter copolymers) can be used for many of the same uses as described heretofor. In addition, copolymers can be used for the prevention of surgical adhesions, tissue adhesives, tissue coatings (sealants) and in tissue engineering.
A preferred application is a method of reducing formation of adhesions after a surgical procedure in a patient. The method includes coating damaged tissue surfaces in a patient with an aqueous solution of a light-sensitive free-radical polymerization initiator and a macromer solution as described above. The coated tissue surfaces are exposed to light sufficient to polymerize the macromer. The light-sensitive free-radical polymerization initiator may be a single compound (e.g., 2,2-dimethoxy-2-phenyl acetophenone) or a combination of a dye and a cocatalyst (e.g., ethyl eosin and triethanol amine).
Additionally, the copolymers (which are preferably crosslinked) can also be used to form hydrogels that are a three-dimensional network of hydrophilic polymers in which a large amount of water is present. In general the amount of water present in a hydrogel is at least 20 weight percent of the total weight of the dry polymer. The most characteristic property of these hydrogels is that it swells in the presence of water and shrinks in the absence of water. The extent of swelling (equilibrium water content) is determined by the nature (mainly the hydrophilicity) of the polymer chains and the crosslinking density.
The kinetics of hydrogel swelling is limited by the diffusion of water through the outer layers of the dried hydrogel. Therefore, while hydrogels swell to a large extent in water, the time it takes to reach equilibrium swelling may be significant depending on the size and shape of the hydrogel. To reduce the amount of time it takes for a hydrogel to reach equilibrium, hydrogel foams may be used. Hydrogels foams may be made by crosslinking polymers in the presence of gas bubbles. The hydrogels foams prepared with macroscopic gas cells will have an open celled structure similar to sponges except that the pore size will generally be an order of magnitude larger.
Hydrogels may be used for many of same uses that have been described for polyoxaesters such as wound dressings materials, since the crosslinked hydrogels are durable, non-antigenic, and permeable to water vapor and metabolites, while securely covering the wound to prevent bacterial infection. Hydrogels may also be used for coatings in general and medical coatings in particular. The hydrogel coatings may provide a smooth slippery surface and prevent bacterial colonization on the surface of the medical instrument. For example hydrogels may be used as coatings on urinary catheter surfaces to improve its biocompatability. Hydrogels may also be used in a variety of applications where the mechanical swelling of the hydrogel is useful such as in catheters as a blend component with a biocompatable elastomer (such as the elastomer described in U.S. Pat. No. 5,468,253 hereby incorporated by reference). Additionally, hydrogels could be used for drug delivery or immobilization of enzyme substrates or cell encapsulization. Other uses for hydrogels have been described in the literature, many of which are discussed in chapter one of Hydrogels and Biodegradable Polymers for Bioapplications, published by the Amercian Chemical Society (which is hereby incorporated by reference herein).
Crosslinking to form crosslinked structures can be performed in a. variety of ways. For example the polymers may be crosslinked while being synthesized, such as by utilizing multifunctional monomers or oligomers. However, crosslinking at other times is also advantageous. For example crosslinking may be performed during the manufacture of a device such by adding a thermal initiator to the copolymer prior to injection molding a device. Additionally, crosslinking of a polymerizable region with a photoinitiator may be performed during stereolithography to form devices. European Patent Application 93305586.5 describes the process for performing stereolithography (with photopolymerizable materials). As previously discussed photoinitiation may be used in vivo to crosslink the copolymers of the present invention for various wound treatments such as adhesion prevention and wound sealing. Coating may also be applied to devices and crosslinked in situ to form films that will conform to the surface of the device.
In a further embodiment of the present invention the polyoxaesters and polymer blends of the present invention can be used in tissue engineering applications as supports for cells. Appropriate tissue scaffolding structures are known in the art such as the prosthetic articular cartilage described in U.S. Pat. No. 5,306,311, the porous biodegradable scaffolding described in WO 94/25079, and the prevascularized implants described in WO 93/08850 (all hereby incorporated by reference herein). Methods of seeding and/or culturing cells in tissue scaffoldings are also known in the art such as those methods disclosed in EPO 422 209 B1, WO 88/03785, WO 90/12604 and WO 95/33821 (all hereby incorporated by reference herein).
The Examples set forth below are for illustration purposes only, and are not intended to limit the scope of the claimed invention in any way. Numerous additional embodiments within the scope and spirit of the invention will become readily apparent to those skilled in the art.
EXAMPLE 1
Preparation of 3,6-Dioxaoctanedioic Acid Dimethylester
The diacid, 3,6-dioxaoctanedioic acid, was synthesized by oxidation of triethylene glycol. The oxidation was carried out in a 500 milliliter, three-neck round bottom flask equipped with a thermometer, an additional funnel, a gas absorption tube and a magnetic spinbar. The reaction flask was lowered into an oil bath resting upon a magnetic stirrer. To the reaction flask was added 157.3 ml of a 60% nitric acid solution; 37.0 g of triethylene glycol was added to the additional funnel. The contents of the flask were heated to 78-80° C. A test tube containing 0.5 g of glycol and one milliliter of concentrated nitric acid was warmed in a water bath until brown fumes started appearing. The contents were then added to the reaction flask. The mixture was stirred for a few minutes; the glycol was then carefully added. The rate of addition had to be monitored extremely carefully to keep the reaction under control. The addition rate was slow enough so that the temperature of the exothermic reaction mixture was maintained at 78-82° C. After the addition was completed (80 minutes), the temperature of the reaction mixture was maintained at 78-80° C. for an additional hour. While continuing to maintain this temperature range, the excess nitric acid and water was then distilled off under reduced pressure (water suction). The syrupy residue was cooled; some solids appeared. The reaction product had the IR and NMR spectra expected for the dicarboxylic acid; the crude product was used as such for esterification.
Esterification of the crude 3,6-dioxaoctanedioic acid was accomplished as follows: To the reaction flask containing 36 g of the crude diacid, was added 110 ml of methanol. This was stirred for 3 days at room temperature after which 15 g of sodium bicarbonate was added and stirred overnight. The mixture was filtered to remove solids. To the liquor was added an additional 10 g of sodium bicarbonate; this mixture was stirred overnight. The mixture was again filtered; the liquor was fractionally distilled.
NMR analysis of the esterified product showed a mixture of dimethyl triglycolate (78.4 mole %) and monomethyltriglycolate (21.6 mole %). No significant condensation of diacid was observed.
EXAMPLE 2
Preparation of Polyoxaester from the Methyl Esters of 3,6-Dioxaoctanedioic Acid and Ethylene Glycol
A flame dried, mechanically stirred, 50-milliliter glass reactor suitable for polycondensation reaction, was charged with 20.62 g (approximately 0.1 mole) of the methyl esters of 3,6-dioxaoctanedioic acid from Example 1, 18.62 g (0.3 mole) of distilled ethylene glycol, and 0.0606 ml of a solution of 0.33M stannous octoate in toluene. After purging the reactor and venting with nitrogen, the temperature was gradually raised over the course of 26 hours to 180° C. A temperature of 180° C. was then maintained for another 20 hours; all during these heating periods under nitrogen at one atmosphere, the methanol formed was collected. The reaction flask was allowed to cool to room temperature; it was then slowly heated under reduced pressure (0.015-1.0 mm) over the course of about 32 hours to 160° C., during which time additional distillates were collected. A temperature of 160° C. was maintained for 4 hours after which a sample, a few grams in size, of the polymer formed was taken. The sample was found to have an inherent viscosity (I.V.) of 0.28 dl/g, as determined in hexaflouroisopropanol (HFIP) at 25° C. at a concentration of 0.1 g/dl. The polymerization was continued under reduced pressure while raising the temperature, in the course of about 16 hours, from 160° C. to 180° C.; a temperature of 180° C. was maintained at for an additional 8 hours, at which time a polymer sample was taken and found to have an I.V. of 0.34 dl/g. The reaction was continued under reduced pressure for another 8 hours at 180° C. The resulting polymer has an inherent viscosity of 0.40 dl/g, as determined in HFIP at 25° C. and at a concentration of 0.1 g/dl.
EXAMPLE 3
Preparation of Polyoxaester with 3,6,9-Trioxaundecanedioic Acid and Ethylene Glycol
A flame dried, mechanically stirred, 250-milliliter glass reactor, suitable for polycondensation reaction, was charged with 44.44 g (0.2 mole) of 3,6,9-trioxaundecanedioic acid, 62.07 g (1.0 mole) of distilled ethylene glycol, and 9.96 milligrams of dibutyltin oxide. After purging the reactor and venting with nitrogen, the contents of the reaction flask were gradually heated under nitrogen at one atmosphere, in the course of about 32
hours, to 180° C., during which time the water formed was collected. The reaction mass was allowed to cool to room temperature. The reaction mass was then heated under reduced pressure (0.015-1.0 mm), gradually increasing the temperature to 180° C. in about 40 hours; during this time additional distillates were collected. The polymerization was continued under reduced pressure while maintaining 180° C. for an additional 16 hours. The resulting polymer has an inherent viscosity of 0.63 dl/g as determined in HFIP at 25° C. and at a concentration of 0.1 g/dl.
EXAMPLE 4
Preparation of Polyoxaester with Polyglycol Diacid and Ethylene Glycol
A flame dried, mechanically stirred, 500-milliliter glass reactor (suitable for polycondensation reaction) was charged with 123.8 g (0.2 mole) polyglycol diacid (molecular weight about 619), 62.07 g (1.0 mole) of distilled ethylene glycol, and 9.96 milligrams of dibutyltin oxide. After purging the reactor and venting with nitrogen, the contents of the reaction flask was heated under nitrogen at one atmosphere, gradually increasing the temperature to 200° C. in about 32 hours; during this time the water formed was collected. The reaction flask was heated gradually under reduced pressure (0.015-1.0 mm) from room temperature to 140° C. in about 24 hours, during which time additional distillates were collected. A polymer sample of about ten grams was taken at this stage, and found to have an I.V. of 0.14 dl/g in HFIP at 25° C., 0.1 g/dl. The polymerization was continued under reduced pressure while heating from 140° C. to 180° C. in about 8 hours, and then maintained at 180° C. for an additional 8 hours. A polymer sample was again taken and found to have an I.V. of 0.17 dl/g. The reaction temperature was then increased to 190° C. and maintained there under reduced pressure for an additional 8 hours. The resulting polymer has an inherent viscosity of 0.70 dl/g as determined in HFIP at 25° C. and at a concentration of 0.1 g/dl.
EXAMPLE 5
Copolymer of Polyoxaester/Caprolactone/Trimethylene Carbonate at 5/5/5 by Weight
A flame dried, 50-milliliter, round bottom single-neck flask was charged with 5 grams of the aliquot of the polyoxaester of Example 4 having an I.V. of 0.14 dl/g, 5.0 grams (0.0438 mole) of ε-caprolactone, 5.0 grams (0.0490 mole) of trimethylene carbonate, and 0.0094 milliliters of a 0.33 molar solution of stannous octoate in toluene.
The flask was fitted with a magnetic stirrer bar. The reactor was purged with nitrogen three times before venting with nitrogen. The reaction mixture was heated to 160° C. and maintained at this temperature for about 6 hours. The copolymer was dried under vacuum (0.1 mm Hg) at 80° C. for about 16 hours to remove any unreacted monomer. The copolymer has an inherent viscosity of 0.34 dl/g, as determined in HFIP at 25° C. and at a concentration of 0.1 g/dl. The copolymer is a viscous liquid at room temperature. The mole ratio of polyoxaester/PCL/PTMC was found by NMR analysis to be 47.83/23.73/28.45.
EXAMPLE 6
Copolymer of Polyoxaester/Caprolactone/Glycolide at 6/8.1/0.9 by Weight
A flame dried, 25-milliliter, round bottom, single-neck flask was charged with 6 grams of the polyoxaester of Example 4 having an I.V. of 0.17 dl/g., 8.1 grams (0.0731 mole) of ε-caprolactone, 0.9 grams (0.008) mole of glycolide and 0.0080 milliliters of a 0.33 molar stannous octoate solution in toluene. The flask was fitted with a magnetic stirrer bar. The reactor was purged with nitrogen three times before venting with nitrogen. The reaction mixture was heated to 160° C. and maintained at this temperature for about 18 hours. The copolymer has an inherent viscosity of 0.26 dl/g in HFIP at 25° C. and at a concentration of 0.1 g/dl. The copolymer is solid at room temperature. The mole ratio of polyoxaester/PCL/PGA/caprolactone was found by NMR analysis to be 56.54/37.73/3.79/1.94.
EXAMPLE 7
In Vitro Hydrolysis
The polyoxaester of Example 3 was tested for in vitro hydrolysis at both 50° C. and at reflux temperature. A 100 mg sample of the polyoxaester, placed in 100 ml of a phosphate buffer solution (0.2 M in phosphate, pH 7.27), was completely hydrolyzed in about 7 days at 50° C., whereas at reflux it was completely hydrolyzed in about 16 hours.
EXAMPLE 8
In Vitro Hydrolysis
Polyoxaester of Example 2 was tested for in vitro hydrolysis at 50° C. and at reflux temperature. A 100 mg sample of the polyoxaester, placed in a 100 ml buffer solution (pH 7.27), was completely hydrolyzed in about 25 days at 50° C., whereas at reflux it was completely hydrolyzed in about 16 hours.
EXAMPLE 9
Preparation of Polyoxaester Based on Polyglycol Diacid with Polyethylene Glycol
To a flame-dried, 250-ml, 2-neck flask suitable for polycondensation reaction, 15.13 grams of polyglycol diacid (m.w. 619g/m; 0.02444 mole), 15.0 grams polyethylene glycol (m.w. 600g/m; Aldrich, 0.025 mole), 3.18 grams ethylene glycol (m.w. 62.07g/m, 0.0512 mole were charged, and dried over night under high vacuum at room temperature. The next day, 2.5 mg of dibutyl tin oxide (m.w. 248.92) was added. The reaction mass, under nitrogen at one atmosphere, was then gradually heated to 200° C. over a period of 16 hours while collecting the distillate. The reaction flask was allowed to cool to room temperature and the pressure reduced. Now under vacuum, it was gradually heated to 180-200° C., and run at this temperature until the desired molecular weight was obtained. The resulting copolymer has an I.V. of 0.63 dl/g.
EXAMPLE 10
Preparation of Polyoxaester Hydrogel Based on Polyglycol Diacid with Polyethylene Glycol
To a flame-dried, 250 ml, 2 neck flask, suitable for polycondensation reaction, 77.34 grams of polyglycol diacid (m.w. 619; 0.125 mole), 63.60 grams of polyethylene glycol (m.w. 600; Aldrich, 0.106 mole), 15.52 grams of ethylene glycol (m.w. 62.07; 0.250 mole), and 2.55 grams of trimethylol propane (m.w. 134.18; 0.019 mole) were charged and dried over night under high vacuum at room temperature. The next day, 12.5 mg of dibutyl tin oxide (m.w 248.92) was charged. The reaction mass, under nitrogen at one atmosphere, was then gradually heated to 190-200° C. over a period of 16 hours while collecting the distillate. The reaction flask was allowed to cool to room temperature and the pressure reduced. Now under vacuum, it was gradually heated to 170° C. and maintained there about 22 hours. The resulting viscous polymer was transferred into a tray for devolatalized in a vacuum oven until a film formed. The resulting film was light brown in color. It swelled in water and was found to disappeared in about two weeks.
EXAMPLE 11
Preparation of Copolymers of Polyoxaester Based on Adipic and Polyglycol Diacids with Polyethylene Glycol
The following is an example of how a copolymer of polyoxaester could be prepared. To a flame-driedi 250-ml, 2-neck flask suitable for polycondensation reaction, 15.13 grams of polyglycol diacid (m.w. 619g/m; 0.02444 mole), 0.893 grams of adipic acid (m.w. 146.14 g/m; 0.00611 mole), 15.0 grams polyethylene glycol (m.w. 600 g/m; Aldrich, 0.025 mole), 3.18 grams ethylene glycol (m.w. 62.07g/m, 0.0512 mole can be charged, and dried over night under high vacuum at room temperature. The next day, a suitable catalyst at a suitable level (i.e. 2.5 mg of dibutyl tin oxide) can be added. The reaction mass, under nitrogen at one atmosphere, can then be gradually heated to 200° C. over a period of 16 hours while collecting the distillate. The reaction flask can be allowed to cool to room temperature and the pressure reduced. Now under vacuum, it can be gradually heated to elevated temperatures (i.e. 180-200° C. or higher) and kept at elevated temperatures until the desired molecular weight is obtained. The ester moieties of the resultant copolymer are approximately 20% adipate in nature. Although the initial charge is rich, on a mole basis, in ethylene glycol, the diol based moieties in the resultant copolymer are much richer in polyethylene glycol-based moieties due to differences in relative volatility.
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The present invention describes a polyoxaester copolymer and blends thereof that may be used to produce hydrogels, surgical devices such as sutures, sutures with attached needles, molded devices, drug matrices, adhesives, sealants and the like. The invention also contemplates a process for producing these polyesters. The polyoxaester copolymers of the present invention are formed from a first divalent repeating unit of formula IA:
[—O—C(O)—R 30 —C(O)—] IA
a second divalent repeating unit of the formula IB:
[O—C(O)—C(R 1 )(R 2 )—O—R 3 —O—C(R′ 1 )(R′ 2 )—C(O)—] IB
and a third repeating unit selected from the group of formulas consisting of:
[—O—R 4 —] A , II
[—O—R 5 —C(O)—] B , III
([—O—R 5 —C(O)] P —O—) L G XI
and combinations thereof. These aliphatic polyoxaesters may be blended with other polymers that are preferably biocompatable.
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RELATED APPLICATIONS
[0001] This application claims benefit of and priority to U.S. Provisional Application Ser. No. 62/002,742 filed May 23, 2014 entitled Method And Device For Treating Pelvic Conditions, which is related to U.S. patent application Ser. No. 14/030,869 filed Sep. 18, 2013 entitled Apparatus And Methods To Modulate Pelvic Nervous Tissue; U.S. patent application Ser. No. 14/285,627 filed May 22, 2014 entitled Apparatus And Methods To Modulate Pelvic Nervous Tissue; U.S. patent application Ser. No. 14/030,905 filed Sep. 18, 2013 entitled Apparatus And Methods To Modulate Bladder Function; and U.S. Provisional Patent Application No. 61/935,753 filed Feb. 4, 2014 entitled Devices And Methods For Treating Conditions Caused By Affarent Nerve Signals, all of which are hereby incorporated by reference herein in their entireties.
BACKGROUND OF THE INVENTION
[0002] Urinary incontinence (UI) is the involuntary leakage of urine. There are several types of urinary incontinence, including urge urinary incontinence (UUI) and stress urinary incontinence (SUI). Urge urinary incontinence is the involuntary loss of urine while suddenly feeling the need or urge to urinate. Stress urinary incontinence, typically affecting females, is the involuntary loss of urine resulting from increased abdominal pressure, such as generated by physical activity, exercising, coughing, sneezing, laughing, lifting, etc. Mixed incontinence combines attributes of SUI and UUI.
[0003] Overactive bladder (OAB) is the strong, sudden urge to urinate, with or without urinary incontinence, usually with frequency and nocturia. The urge associated with overactive bladder can be assessed using the subjective experience of the patient, with or without any objectively verifiable metric, condition, behavior, or phenomena.
[0004] Historically, attempts have been made to translate the subjective patient experience of overactive bladder into a verifiable clinical test. Based upon work in spinal cord injury patients, it was hypothesized that the sensation of urgency and the result of urine leakage was due to non-volitional urinary bladder detrusor muscle contractions. Consequently, there was a push to implement urodynamic testing to observe and quantify the presumed detrusor contractions. However, the results found a poor correlation (e.g., 60%) between observed detrusor overactivity and the experience of urgency, and also found that asymptomatic individuals may exhibit detrusor contractions during urodynamic testing.
[0005] Given the limitations of urodynamic testing, the diagnosis and treatment decisions for overactive bladder transitioned to being assessed wholly by the patient's subjective experience. However, the detrusor muscle and its contractions are still considered to have a major role in overactive bladder.
[0006] Bladder control is a complex combination of voluntary and involuntary neurologic control, which responds to a highly distributed set of afferent (sensory) nerves associated with the bladder. Also, there is evidence of a myogenic origin for at least a portion of bladder wall contractile activity. While there are some descriptive hallmarks of idiopathic overactive bladder (e.g., thickened wall, characteristic “patchy” denervation, changes in smooth muscle and collagen morphology, increased electrical connectivity), there is no specific anatomic cause of OAB (e.g., a lesion, defect, injury, etc.), and also it is believed that there is no commensurate remedy for the cause. Neurogenic injury (e.g., spinal cord injury) and bladder outlet obstruction (BOO) can both lead to overactive bladder due to a chronic state of bladder inflation and a “high pressure” bladder. However, resolution of an outlet obstruction fails to rectify overactive bladder symptoms in a significant fraction (e.g., 25%) of these patients.
[0007] Overactive bladder affects at least 33 million patients in the United States alone, representing 16% of the adult United States population and roughly $12 billion dollars in healthcare cost. Overactive bladder and urinary incontinence significantly affect the quality of life and the ability of patients to maintain their lifestyle, including socializing, mobility, or independence. Further, urinary incontinence is one of the most common reasons for entering long-term care facilities, such as nursing homes, and is also a significant risk factor for injury due to falls resulting from hurrying to the toilet in response to urge.
[0008] Referring to FIGS. 1-3 , the anatomy of the female bladder is described to provide context for discussion of previously-known treatment modalities, and is illustrative of why a significant unmet need for improved treatment modalities remains. In particular, FIG. 1 depicts a lateral sectional of the anatomical structures of a bladder (B) and a urethra (U), while FIG. 2 depicts an anterior sectional view of the bladder and urethra. FIGS. 1-2 further illustrate a trigone (T), ureteral ostium (O) (also referred to as a ureteral orifice), detrusor muscle (D), a neck (N), an interureteric crest (C), a fundus (F), and a body (BB).
[0009] FIG. 3 depicts a cross sectional view of a wall of the bladder, including an intravesical region (IR) (also referred to as the cavity), mucous membrane (also referred to as the mucosa), lamina propria (LP), muscularis propria (MP), adventitia (A), and perivesical fat (PF). The mucous membrane lines the intravesical region (IR) of the bladder and includes a three-layered epithelium, collectively referred to as transitional cell epithelium (TCE) or urothelium, and basement membrane (BM). The three layers of the transitional cell epithelium include the basal cell layer, the intermediate cell layer, and the surface cell layer. The basal cell layer can renew the transitional cell epithelium by cell division. New cells can migrate from the basal layer to the surface cell layer, and the surface cell layer can be covered by glycosaminoglycan (GAG) layer (GL). The function of GAG layer is controversial, possibly serving as an osmotic barrier or even an antibacterial coating for transitional cell epithelium. The basement membrane is a single layer of cells that separates transitional cell epithelium from the lamina propria.
[0010] Lamina propria (also referred to as the submucosa or suburothelium) is a sheet of extracellular material that may serve as a filtration barrier or supporting structure for the mucous membrane and includes areolar connective tissue and contains blood vessels, nerves, and in some regions, glands. Muscularis propria (also referred to as the detrusor muscle or the muscle layer) may be interlaced with lamina propria and may have three layers of smooth muscle, the inner longitudinal, middle circular, and outer longitudinal muscle.
[0011] When the bladder is empty, the mucosa has numerous folds called rugae. The elasticity of rugae and transitional cell epithelium allow the bladder to expand as the bladder fills with fluid. The thickness of the mucosa and muscularis propria can range between approximately 2 to 5 mm when the bladder is full and between approximately 8 to 15 mm when the bladder is empty.
[0012] The outer surface of muscularis propria may be lined by adventitia A about the posterior and anterior surface of the bladder or by the serosa about the superior and upper lateral surfaces of the bladder. Perivesical fat (PF) can surround the bladder outside of the serosa or adventitia. In some cases, a variety of fascia layers may surround or support the organs of the pelvis. Collectively, the fascias near the urinary bladder can be referred to as perivesical fascia.
[0013] A number of therapies have been developed for treating overactive bladder, including delivery of anticholinergic drugs, bladder retraining, sacral nerve stimulation (SNS), intravesical drug infusions, surgical denervation procedures, surgeries to increase bladder volume (e.g., detrusor myomectomy, augmentation cystoplasty) and botulinum toxin (e.g., Botox®, Dysport®, etc.) injections into the bladder wall. Each of these therapies has drawbacks, as described below.
[0014] Anticholinergic drugs, used alone or in combination with traditional nonsurgical approaches, such as bladder retraining, Kegel exercises, biofeedback, etc., often is used as first-line therapy for overactive bladder; however, the mode of action is uncertain. Anticholinergic drug use was initially thought to decrease contractions of the detrusor muscle during the filling stage (e.g., detrusor muscle overactivity, unstable detrusor muscle, etc.). However, it is now believed that anticholinergic drugs may not change detrusor muscle contractility, but instead modulate afferent (e.g., cholinergic) nervous traffic to the central nervous system.
[0015] Efficacy of anticholinergic drugs is generally quite modest, as approximately 50% of patients find such therapy subjectively inadequate. A reduction of 10% to 20% in the number of micturations per day (e.g., from 11 micturations to 9 micturations) and a reduction of 50% in urinary incontinence episodes (e.g., from 2 per day to 1 per day) is typical. However, these effects are frequently inadequate to significantly improve patient quality of life (QOL). Many patients would not even notice a change of 2 micturations per day unless they are keeping a log for a formal study. The remaining urinary incontinence episodes, although slightly less in number, continue to maintain the stigma and lifestyle limitations of the disease, such as the inability to travel or to be active, social withdrawal, etc. In addition, anticholinergic drugs can have side effects, including dry mouth, constipation, altered mental status, blurred vision, etc., which may be intolerable, and in many instances outweigh the modest benefits attained. Approximately 50% of patients abandon anticholinergic therapy within 6 months.
[0016] Sacral nerve stimulation (SNS) has a higher level of efficacy (e.g., up to 80% in well-selected and screened patients), but here too the mode of action is not well understood. The clinical benefit of SNS for urinary incontinence was a serendipitous finding during clinical trials of SNS for other conditions. The SNS procedure has a number of drawbacks: it is expensive and invasive, and requires surgery for temporary lead placement to test for patient response, followed by permanent lead placement and surgical implantation of a pulse generator in patients who responded favorably to the temporary lead. Regular follow-ups also are required to titrate SNS stimulation parameters, and battery replacements are necessary at regular intervals.
[0017] A variety of surgical denervation or disruption procedures have been described in the literature, but most have showed poor efficacy or durability. The Ingelman-Sundberg procedure, first developed in the 1950s and described in Ingelman-Sundberg, A., “Partial denervation of the bladder: a new operation for the treatment of urge incontinence and similar conditions in women,” Acta Obstet Gynecol Scand, 38:487, 1959, involves blunt surgical dissection of the nerves feeding the lateral aspects of the bladder near its base. The nerves are accessed from the anterior vaginal vault, with the dissection extending bilaterally to the lateral aspect of the bladder. The denervation process is accomplished somewhat blindly, using blunt dissection of the space and targeting the terminal pelvic nerve branches. Although capable of producing promising results, the procedure as originally proposed entails all of the drawbacks and expense normally associated with surgical procedures.
[0018] McGuire modified the Ingelman-Sundberg procedure in the 1990s, as described in Wan, J., et al., “Ingelman-Sundberg bladder denervation for detrusor instability,” J. Urol., suppl., 145: 358A, abstract 581, 1991, to employ a more limited and central dissection within the serosal layer of the bladder, staying medial to the vaginal formices. Surgical candidates for the Modified Ingelman-Sundberg procedure can be screened to isolate likely “responders” using sub-trigonal anesthetic injections. As reported in 1996 by Cespedes in Cespedes, R. D., et al., “Modified Ingelman-Sundberg Bladder Denervation Procedure For Intractable Urge Incontinence,” J. Urol., 156:1744-1747 (1996), 64% efficacy was observed at mean 15 month follow-up following the procedure. In 2002, Westney reported in Westney, O. L., et al., “Long-Term Results Of Ingelman-Sundberg Denervation Procedure For Urge Incontinence Refractory To Medical Therapy,” J. Urol., 168:1044-1047 (2002), achieving similar efficacy at mean 44 month follow-up after the procedure. More recently, in 2007, Juang reported in Juang, C., et al., “Efficacy Analysis of Trans-obturator Tension-free Vaginal Tape (TVT-O) Plus Modified Ingelman-Sundberg Procedure versus TVT-O Alone in the Treatment of Mixed Urinary Incontinence: A Randomized Study,” E. Urol., 51:1671-1679 (2007), using a combination of a transvaginal tape (TVT) sling (the “gold standard” surgical therapy for stress incontinence) and the Modified Ingelman-Sundberg procedure for mixed incontinence patients and showed a significant benefit for including the Modified Ingelman-Sundberg procedure, over the TVT sling alone, out to 12 months follow-up following the procedure.
[0019] Despite its clinical success, however, the Modified Ingelman-Sundberg procedure has not been widely adopted, as it is highly invasive and requires general anesthesia. Further, the terminal nerve branches are not visible to a surgeon, and thus, the dissection must be performed using approximate anatomical landmarks rather than using direct visualization of target nerve branches. Possible complications of the Modified Ingelman-Sundberg procedure include the risks associated with anesthesia, blood loss, vaginal numbness or fibrosis, adhesions, fistulas, vaginal stenosis, wound infection, or dyspareunia (pain with intercourse). Perhaps most importantly, efficacy of the Modified Ingelman-Sundberg procedure may be dependent upon surgical skill and technique.
[0020] More recently, another therapy involving injection of botulinum toxin (e.g., Botox®) into the bladder wall has been developed to address the symptoms of overactive bladder by blocking nerve traffic and causing temporary muscle paralysis following injection. During the injection procedure, which may be performed in a physician's office under local anesthesia, a cystoscope is introduced into the bladder through the urethra and a number of separate cannula injections (e.g., 20-30) are made into the bladder wall. Initially the trigone, the area of the bladder defined by the ostia of the two ureters and the urethra, was avoided due to concerns about procedural pain due to dense afferent innervation of the trigone region and the potential for vesicoureteral reflux. However, the trigone region has more recently been included, and sometimes specifically targeted to the exclusion of the dome of the bladder. Initially, botulinum toxin was assumed to act only on the efferent motor nerves (e.g., causing partial paralysis of the detrusor muscle). More recent research indicates that botulinum toxin may have an effect on afferent sensory nerves as well. U.S. Pat. No. 8,029,496 to Versi provides an example of a system for delivering such a therapeutic agent to the trigone of the bladder through the vaginal wall.
[0021] Typically, botulinum toxin injections achieve a fairly high level of efficacy (e.g., resolution of symptoms), with maximum changes in cystometric capacity peaking at 4 weeks and complete continence being achieved in about half of patients. However, botulinum toxin does carry with it the risks of systemic effects, such as flu-like symptoms, nausea, weakening of respiratory muscles, transient muscle weakness, allergic reaction, or developed sensitivity. Other adverse events associated with botulinum toxin injections include acute urinary retention (AUR), large postvoid residual volume (PVR), difficulty in urination (“straining”), and urinary tract infection (UTI). Challenges with botulinum toxin therapy include procedural skill (e.g., dexterity with cystoscope and needle), uncontrolled drug diffusion, variable needle penetration depth, and reproducibility of technique. In addition, the effects of botulinum toxin wear off with time, typically after 6-9 months, requiring repeat injections for the lifetime of the patient.
[0022] Stress urinary incontinence, typically affecting females, is an anatomic issue where the pelvic floor has been damaged and weakened, such as during childbirth. Here, front line therapies are conservative (e.g., Kegel exercises or biofeedback), and a variety of minimally invasive surgical therapies are available as second line therapies. Examples of these second line therapies include sling procedures, bladder neck suspension, transvaginal tape (TVT), etc. In each, the procedure is a day surgery performed on an outpatient basis. Success rates are high, and the procedures have been embraced by the medical community.
[0023] In addition, new therapies have been developed to treat stress urinary incontinence, such as the Renessa system offered by Novasys Medical, Inc., which is used in an office-based procedure. U.S. Pat. No. 6,692,490 to Edwards, assigned to Novasys Medical, discloses the treatment of urinary incontinence and other disorders by the application of energy and drugs.
[0024] Finally, a majority of males will develop some degree of urinary obstruction from benign prostate hyperplasia (BPH), or “enlarged prostate”, over their lifetime. Since urinary obstruction is known to be a cause of overactive bladder, bladder symptoms in males are generally presumed to be secondary to the enlarged prostate. However, resolution of the urinary obstruction (e.g., by one of the many variants of transurethral treatments of the prostate) does not resolve the bladder symptoms in about a quarter of the patients. Thus, it would be desirable to offer a minimally invasive therapeutic procedure targeting these remaining patients whose symptoms remain after prostate therapy.
[0025] Further, there is a growing preference for “watchful waiting” for prostate disease, even for cases of actual prostate cancer, and many of these patients will develop symptoms of overactive bladder due to the urinary obstruction from their growing prostate. Thus, there is the potential to provide a therapy that targets the bladder symptoms prior to or instead of providing therapy targeting the prostate itself.
[0026] Males also may experience idiopathic OAB, that is OAB not secondary to an enlarged prostate or other urinary obstruction, and require a primary therapy for the OAB symptoms.
[0027] In view of the foregoing, it would be desirable to provide a minimally invasive procedure for modulating bladder function to treat or resolve overactive bladder and provides durable relief for patients suffering from these debilitating conditions.
OBJECTS AND SUMMARY OF THE INVENTION
[0028] The invention is directed to apparatus and methods configured to perform a variety of foreseen and unforeseen medical procedures and therapies. By way of non-limiting example, the apparatus and methods of the invention are suited to provide therapy to non-mucosal target tissue (or a target volume of tissue) to modulate bladder function. In an example, energy can be delivered to denervate selected portions of the bladder, such as afferent nerves located within or proximate to the trigone region of the bladder wall, to modulate bladder function and thereby provide relief for at least one of a sense of urge, incontinence, frequency, nocturia, bladder capacity, or pain.
[0029] In some examples, denervation may be accomplished by delivering thermal energy (e.g., using RF energy, microwaves, or high intensity focused ultrasound) to layers of the bladder wall beneath the mucosal layer, such as within or proximate to the trigone region. In the context of this disclosure, tissue of the female anatomy targeted for energy delivery may include one or more tissue layers of the bladder wall beneath the mucosa and extending to (but not including) the anterior vaginal wall, and are collectively referred to herein as “non-superficial tissue.” Further, in the context of this disclosure, tissue of the male anatomy targeted for energy delivery may include one or more layers of the bladder wall beneath the mucosa and extending to and including the perivesical fat layer, and in the context also is referred to as “non-superficial tissue”. In still other examples, thermal energy may be delivered to neural tissue, such as a pelvic nerve or its branches, within or proximate to the bladder wall to modulate nerve traffic to or from at least a portion of the bladder, thereby modulating bladder function. In accordance with some examples, suction may be used to grasp and conform a mucosal surface of the bladder wall to a first surface of a device, and energy can be delivered to non-superficial target tissue at a substantially uniform depth from the mucosal surface. Cooling also may be provided to reduce heat buildup in the mucosa. However, in some examples, a mucosal surface of the bladder wall superficial to the non-superficial target tissue can be retained substantially intact without cooling, such as by inserting an energy delivery element in the non-superficial target tissue at a substantially uniform distance from the first surface of the device and delivering energy to the non-superficial target tissue from that substantially uniform depth beneath the mucosal surface. The systems and methods described herein may be configured to deliver energy, such as thermal energy, to target tissue either from within a lumen or cavity of a body organ, for example, the bladder, or from a lumen or cavity of an adjacent organ, such as the vagina.
[0030] In the alternative, or optionally in addition, the systems and methods described herein may provide that one or more areas of the bladder be isolated or supported such as to suppress the sense of urgency. For example, surgical barriers or treatments may be used to reduce stretch of a selected region of the bladder, such as the trigone, or alternatively used as an adjunct to energy delivery to prevent nerve regrowth in a treated portion of the bladder.
[0031] This overview is intended to provide an overview of subject matter of the present patent application. It is not intended to provide an exclusive or exhaustive explanation of the invention. The detailed description is included to provide further information about the present patent application.
BRIEF DESCRIPTION OF THE DRAWINGS
[0032] These and other aspects, features and advantages of which embodiments of the invention are capable of will be apparent and elucidated from the following description of embodiments of the present invention, reference being made to the accompanying drawings, in which
[0033] FIG. 1 is a lateral sectional depiction of the anatomy of a female bladder and urethra;
[0034] FIG. 2 is an anterior sectional depiction of a female bladder and urethra;
[0035] FIG. 3 is a cross sectional depiction of bladder wall tissue;
[0036] FIG. 4 is a perspective view of an embodiment of a device of the invention;
[0037] FIG. 4 a is a perspective view of the device of FIG. 4 with the endoscope in a partially retracted position;
[0038] FIG. 5 is a detail perspective view of the portion of the device shown in area 5 of FIG. 4 ;
[0039] FIG. 5 a is a detail perspective view of the portion of the device shown in area 5 a of FIG. 4 a;
[0040] FIG. 6 is a perspective view taken from a proximal end of an embodiment of a device of the invention;
[0041] FIG. 7 is a plan view of an embodiment of a device of the invention;
[0042] FIG. 8 is an elevation view of an embodiment of a device of the invention;
[0043] FIG. 9 is a bottom view of an embodiment of a device of the invention;
[0044] FIG. 10 is an elevation of an embodiment of a suction head of the invention;
[0045] FIG. 11 is a perspective view of an embodiment of a suction head of the invention;
[0046] FIG. 12 is a plan view of an embodiment of a suction head of the invention;
[0047] FIG. 13 is a plan view of an embodiment of a suction head of the invention;
[0048] FIG. 14 is a perspective view of an embodiment of a suction head of the invention with electrode sets in an extended position;
[0049] FIG. 15 is a cutaway view of an embodiment of a suction head of the invention showing the detail of the inner suction chamber;
[0050] FIG. 16 is an axial cross sectional view of an embodiment of a suction head of the invention;
[0051] FIG. 17 is a depiction of a side view of an area of a female bladder targeted during an example of a method of the invention;
[0052] FIG. 18 is an anterior sectional depiction of a bottom portion of a female bladder;
[0053] FIG. 19 is a depiction of an embodiment of a device of the invention being inserted into a female bladder;
[0054] FIG. 20 is a depiction of a step of an embodiment of a method of the invention;
[0055] FIG. 21 is a depiction of a step of an embodiment of a method of the invention;
[0056] FIGS. 22-33 depict various ablation patterns made practicing an embodiment of a method of the invention;
[0057] FIG. 34 is an elevation of a distal end of an embodiment of the invention;
[0058] FIG. 35 is an elevation of a distal end of an embodiment of the invention;
[0059] FIG. 36 is an elevation of a distal end of an embodiment of the invention;
[0060] FIG. 37 is a perspective view of a distal end of an embodiment of the invention;
[0061] FIG. 38 is an elevation of an embodiment of the invention;
[0062] FIG. 39 is an elevation of an embodiment of the invention;
[0063] FIG. 40 is a sectional view of the embodiment of FIG. 38 taken along section lines 40 - 40 ;
[0064] FIG. 41 is a sectional view of the embodiment of FIG. 38 taken along section lines 41 - 41 ;
[0065] FIG. 42 is a sectional view of the embodiment of FIG. 38 taken along section lines 42 - 42 ;
[0066] FIG. 43 is a perspective view of an embodiment of a device of the invention;
[0067] FIG. 44 is a bottom view of an embodiment of a device of the invention;
[0068] FIG. 45 is a detail view of cutout 45 of FIG. 44 ;
[0069] FIG. 46 a is a cross-sectional view of a distal portion of an embodiment of the invention;
[0070] FIG. 46 b is a cross-sectional view of a distal portion of an embodiment of the invention employing a tilted suction head;
[0071] FIG. 47 is a side elevation of an embodiment of a device of the invention;
[0072] FIG. 48 is a sectional view of the embodiment of FIG. 47 taken along section lines 48 - 48 ;
[0073] FIG. 49 is a sectional view of the embodiment of FIG. 47 taken along section lines 49 - 49 ;
[0074] FIG. 50 is a sectional view of the embodiment of FIG. 47 taken along section lines 50 - 50 ;
[0075] FIG. 51 is a side elevation of an embodiment of a device of the invention;
[0076] FIG. 52 is a side elevation of an embodiment of a device of the invention;
[0077] FIG. 53 is a perspective view of an embodiment of a distal end of a device of the invention;
[0078] FIG. 54 is a side elevation of an embodiment of a distal end of a device of the invention;
[0079] FIG. 55 is a perspective view of an embodiment of a distal end of a device of the invention;
[0080] FIG. 56 is an elevation view of a distal end of an embodiment of the invention being used with a flexible embodiment of an endoscope; and,
[0081] FIG. 57 is an elevation view of a distal end of an embodiment of the invention being used with an articulated embodiment of an endoscope.
DESCRIPTION OF EMBODIMENTS
[0082] Specific embodiments of the invention will now be described with reference to the accompanying drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. The terminology used in the detailed description of the embodiments illustrated in the accompanying drawings is not intended to be limiting of the invention. In the drawings, like numbers refer to like elements.
[0083] FIG. 4 illustrates an embodiment of a system 10 for treatment of body tissue, such as the bladder. Generally, the system includes a treatment device 20 and may include an endoscope 12 . The treatment device 20 has a proximal end 22 , a distal end 24 , and an elongate shaft portion 26 between the proximal end 22 and the distal end 24 .
[0084] The proximal end 22 of the treatment device 20 may include a handle assembly 30 , detailed in FIG. 5 . The handle assembly 30 may include a body 32 , a sliding mechanism 34 ( FIGS. 4 a and 5 a ), one or more suction ports 36 , and at least one receiver 38 for an electrode set, described below. The handle assembly 30 generally serves to secure the endoscope position relative to the treatment device and also to provide a comfortable grip for the user. To this end, the handle assembly 30 may take on any number of ergonomic shapes. An alternative shape to that shown in the Figures is a “pistol grip” shape.
[0085] The sliding mechanism 34 functions to receive and control the longitudinal or axial placement of the endoscope 12 relative to the treatment device. The sliding mechanism 34 includes a sliding tube 40 (see FIG. 5 a ) that is slidingly received by the body 32 of the handle assembly 30 . The sliding tube 40 includes a stop 42 that rides within a groove 44 in the body 32 . The stop 42 and groove 44 define the extents of the longitudinal movement, and prevent rotation, of the sliding mechanism 34 relative to the body 32 . It can be seen that the body 32 accommodates an endoscope 12 inserted into a proximal end thereof. A conventional Hopkins rod endoscope is shown, but alternative imaging devices are contemplated as well, such as endoscopes having cameras at or near their tips. The sliding tube 40 can be seen in a fully inserted position in FIGS. 4 and 5 and a partially retracted position in FIGS. 4 a and 5 a . A camera (not shown) may be connected to the eyepiece.
[0086] FIG. 6 shows a perspective view of the proximal end of the handle assembly 30 without the endoscope 12 inserted therein. It can be seen that the sliding tube 40 defines a proximal end of a scope channel 16 that receives the endoscope 12 and extends substantially the length of the treatment device 20 . The sliding tube 40 also provides a cutout 46 for accommodating a vertical control post and/or light input port 18 of the endoscope 12 . The cutout 46 establishes a radial relationship between the treatment device 20 and the endoscope 12 when the endoscope is fully inserted into the sliding tube 40 of the sliding mechanism 34 . The hemispherical design of the cutout allows a user to easily retract the endoscope 12 slightly from the sliding tube 40 and rotate the scope 12 if the user desires to alter the viewing angle of the scope without rotating the treatment device 20 within the patient.
[0087] The sliding mechanism 34 also includes a locking tab 48 that extends through the sliding tube 40 and frictionally engages the endoscope 12 when depressed. The locking tab 48 , when engaged with the endoscope 12 , prevents longitudinal movement of the endoscope 12 relative to the sliding tube 40 .
[0088] While the sliding mechanism 34 is a manual slide mechanism, other configurations are anticipated. Non-limiting examples of these other configurations include dials, rack-and-pinion mechanisms, trigger mechanisms, rocker switch configurations, worm drives, gears, stepper motors, and the like.
[0089] Below the scope channel 16 , the body 32 of the handle assembly includes at least one suction port 36 . The embodiment shown in the Figures includes two suction ports 36 . These suction ports 36 are in fluid communication with a suction channel 17 that extends the length of the treatment device 20 . The suction ports 36 are shown with standard Luer-Lok fittings but this is shown by way of example only and is not intended to be limiting.
[0090] Additionally, these suction ports 36 may be used for irrigation or infusion purposes. Flow control valves (not shown), such as stopcocks may be used to connect suction and/or aspiration sources to the ports 36 . One or more of the ports 36 may also act as a vent to the atmosphere. It is also envisioned that one or more of the fittings may be permanently or episodically connected to a syringe, which may be used to instill or extract volumes of fluid into or out of the anatomic structure in which the device is used.
[0091] The body 32 of the handle assembly 30 also may define one or more receiver 38 for an electrode set. The embodiment shown in the figures includes a receiver 38 that accommodates two electrode sets 54 , one on either side of the scope channel 16 and the suction channel 17 . The receiver 38 is sized and shaped to house the proximal ends of the electrode sets 54 and provides cannula ports 50 that lead to cannula channels 52 . The cannula ports 50 are shown as being funneled in order to facilitate easy cannula insertion.
[0092] The electrode sets 54 are best shown in FIGS. 4 and 7 - 9 . The electrode sets 54 generally include an electrode 56 and a cannula 58 extending distally therefrom. Connecting wires connecting the electrodes 56 to a power source are to be understood but not shown. The electrode 56 extends through and energizes the cannula at the tip. An all-in-one electrode set, in which the conductive end of the electrode is not contained within a cannula is also contemplated. For purposes of clarity herein, the electrode 56 is considered that portion of the electrode set that is connected to a power supply and provides the circuitry for energizing the cannula. The cannula 58 is the energized portion of the electrode set that transfers energy into the patient.
[0093] The electrode sets 54 and corresponding cannula channels 52 are sized such that, when the electrode sets are fully inserted into the cannula channels 52 so that the hubs of the cannulas 58 abut against the receiver 38 , the distal ends of the cannulas 58 extend a desired amount past the distal ends 80 of the cannula channels. FIG. 14 shows the distal end of the device with the cannulas 58 fully inserted. FIG. 14 also shows insulation 59 surrounding all but the ends of the cannulas 58 , thereby limiting the effective treatment portion of the cannulas 58 to the distal ends of the cannulas.
[0094] The electrode sets 54 , once placed in the channels 52 and receiver 38 , are movable between a retracted position and an inserted position. The inserted position as described above, is achieved when the electrode sets 54 are fully inserted into the channels 52 so that the hubs of the cannulas 58 abut against the receiver 38 . The retracted position is achieved when the electrodes 56 are pulled proximally as shown in FIG. 4 . In the retracted position, the distal ends of the cannulas 58 are contained within the cannula channels 52 and do not extend out of the cannula channel ends 80 . The receiver 38 is sized to accommodate the electrodes 56 even when the electrode sets 54 are in the retracted position.
[0095] It is to be understood that any suitable electrode may be utilized with treatment device. While a preferred type is one that has a needle-shaped end or where an electrode resides within a cannula, such as that manufactured by Stryker, Cosman, Neurotherm, other electrodes are also contemplated, such as electrodes that are “one piece” and capable of directly penetrating tissue without an external cannula. It is also preferable to use an electrode of the type that has a temperature measurement element at its tip, such as an embedded thermocouple or thermistor. The types manufactured by Stryker, Cosman, Neurotherm include this feature.
[0096] It is anticipated that embodiments of the system 10 may be provided wherein the electrodes and cannulas are integral to the treatment device itself rather than using separate components that are assembled by the operator. Further, it is anticipated that the cannula advancement, shown here as manual axial movement of each cannula separately, may be alternatively configured to include coupling of the cannulas for simultaneous advancement and mechanisms to advance the cannulas.
[0097] The embodiment depicted in FIG. 4 does not include a mechanism for advancing the cannulas 58 from the retracted to the advanced positions, as it is envisioned that this may be done manually. However, such mechanisms are envisioned and could be provided for faster easier operation of the device. Examples of such mechanisms include trigger mechanisms or rotational helically threaded mechanisms to advance, and possibly also retract the cannulas. Also anticipated are “spring loaded” mechanisms whereby stored energy, preferably in the form of a compacted spring, is released to drive the cannulas into the tissue.
[0098] It is envisioned that one or two electrode sets may be used to ablate tissue. If two electrode sets are utilized, as shown in the figures, a bi-polar current may be applied, which concentrates current in relatively planar space between the exposed portions of the cannulas.
[0099] Additionally, if two electrode sets are used in a bi-polar configuration (or more than two cannulas, but multiplexed such that they are energized in pairs) wherein the cannulas are parallel to each other along their uninsulated portion, the result is an energy deposition region which is uniform in cross section along the length of the uninsulated length. i.e., a treatment that is uniform in thickness and width along the length of the cannula.
[0100] Referring to FIGS. 7-9 , distal of the handle assembly 30 is the shaft portion 26 . The shaft portion 26 is generally made up of the scope channel 16 , the suction channel 17 and the cannula channels 52 . The cannula channels 52 may be curved, as shown, to provide a smaller device profile at the distal aspect. The shaft portion 26 is shaped and sized for insertion into a female urethra and may be relatively rigid, considering that the female urethra is relatively short and straight, compared to the male anatomy. An embodiment of the device designed for use with the male anatomy is substantially similar to the embodiments shown in the figures except that it may utilize a flexible shaft portion and may include a steering mechanism.
[0101] The treatment device 20 has a distal end 24 , several embodiments of which are detailed in FIGS. 10-15 . The distal end 24 generally includes a suction head 60 , distal cannula channel ends 80 , an endoscope channel distal end 90 , and a tube holder 94 .
[0102] The suction head 60 includes a flat face 62 and heel portion 63 with one or more angled or curved faces 64 . These faces 62 and 64 define at least one suction aperture 66 . The embodiments shown in the Figures include a plurality of suction apertures 66 in various shapes and arrangements, each of which is described in more detail below. The suction apertures 66 lead to a suction chamber 68 that is in fluid communication with the suction channel 17 .
[0103] The suction head 60 may include a rounded, atraumatic distal end. The flat face 62 may extend from the distal end of the suction head 60 to the heel portion 63 . The shape of the suction head 60 is designed to seal itself to soft tissue when a suction is applied to the suction chamber 68 . The flat face 62 establishes a seal with the soft tissue being targeted while the faces 64 of the heel portion 63 provide a gentle transition to the cannula channel ends 80 .
[0104] FIG. 16 shows an axial cross section of the suction head 60 taken at a mid-point of the flat face 62 . It is shown that the shape of the suction head 60 may be generally semi-circular. It may be formed from a portion of tube cut away, with a relatively flat face attached thereto. Apertures 66 may be cut or otherwise formed in the face to form openings into the interior suction chamber 68 of the suction head 60 .
[0105] As stated above, the suction apertures 66 may be configured with various sizes, shapes and arrangements. By way of example only, FIG. 11 shows an embodiment that uses four longitudinally-elongated apertures 66 in a 2×2 arrangement in the flat face 62 and a single aperture 66 in the angled face 64 . FIG. 12 shows an embodiment whereby the flat face 62 has 12 circular apertures 66 in a 2×6 arrangement and a heel portion 63 has two angled faces 64 , one with two apertures 66 and one with a single aperture 66 . FIG. 13 shows an embodiment whereby the flat face 62 has six transversely elongate apertures 66 and a heel portion 63 with a first angled face 64 having a similar transversely elongate aperture 66 and another angled face 64 with a single circular aperture 66 .
[0106] Alternatively, or additionally, the apertures 66 may be square or any other suitable shape, and combinations of various sizes and shapes are further contemplated both for the face and for the heel portion 63 . Screen material (not shown) covering one or more of the windows is also contemplated. While the suction face shown in the figures is relatively planar, it is further contemplated that the face may have additional features, such as a raised rim at or near the edge, or along one or more of the windows, or recessed features such as plugs that limit tissue incursion into the suction windows.
[0107] As stated above, the apertures 66 lead into the suction chamber 68 , which is in fluid communication with the suction channel 17 . The suction chamber 68 is best shown in FIG. 15 . In this embodiment, the suction chamber 68 includes a baffle 72 . The baffle 72 provides a barrier between the portion of the suction chamber 68 directly adjacent the flat face 62 of the suction head 60 and the portion of the suction chamber adjacent, or proximal of, the heel portion 63 . When suction is applied to tissue, a balance is sought between the strength of the vacuum being applied and the thickness and resiliency of the tissue. If the tissue is too flexible for a given vacuum level, it may be that the tissue is drawn into the suction chamber 68 . The baffle 72 ensures that the suction chamber 68 is not completely blocked by tissue. Thus, even if tissue is drawn into the heel portion 63 , a path exists on the opposite side of the baffle 72 for a vacuum to be established adjacent the flat face 62 .
[0108] The heel portion 63 serves at least two functions. A first function of the heel portion 63 is to hold the tissue being engaged by the apertures 66 in the angled faces 64 and prevent that tissue from being pushed away from the suction head 60 when the electrode sets are being advanced into the tissue. The orientation of the angled faces 64 assists in resisting longitudinal movement by the tissue as a result of the advancement of the electrode sets.
[0109] As discussed above, a second function of the heel portion 63 is to provide a transition between the flat face 62 and the cannula channel ends 80 . The vertical separation 74 ( FIG. 10 ) between the flat face 62 and the cannula channels 52 helps define the depth at which the electrode sets/cannulas will penetrate and treat the targeted tissue. This vertical separation 74 allows the electrode sets to engage the targeted tissue layer below the surface while avoiding or minimizing treatment of the surface layer of the bladder interior.
[0110] More specifically, for bladder applications such as ablation of portions of the trigone region of the bladder for treatment of overactive bladder, an example of a desired spacing is between 0.5 and 5.0 mm and preferably between 1.0 and 4.0 mm. In this manner, it is believed that the thermal treatment of the submucosal tissue is concentrated at around 0.0 to 7.0 mm depth from the bladder surface, which is where disruption of the afferent nerves is believed to be effective, while minimizing thermal effects at the surface of the bladder. Greater or lesser spacing is also contemplated. The horizontal spacing 76 between the cannulas has an impact on the width of the thermal treatment zone. A preferred spacing (shown in FIG. 14 ) is from 3 to 5 mm.
[0111] FIG. 10 illustrates a configuration where the axis of the cannula and the suction head are parallel (i.e., the cannula is at a uniform distance from the flat face 62 along the entire length of the face 62 ). While this is a preferred embodiment, it is also anticipated that certain non-zero angles between the paddle and cannula may offer certain benefits. For example, a non-zero angle could be chosen to bias the distal portion of the cannulas (and thus the therapy) to be at a different distance, either to bias the therapy to a different, preferential, depth, or to correct for differences in tissue properties or cannula tracking through the tissue.
[0112] FIGS. 10 and 15 show that the device distal end 24 also includes the endoscope channel end 90 . The endoscope channel end 90 is angled such that, when the scope is retracted, the channel end presents an atraumatic profile.
[0113] FIG. 10 shows the end of the endoscope 12 in a partially advanced position such that it protrudes out of the endoscope channel end 90 . (By way of comparison, FIG. 11 shows the scope 12 in a fully advanced position). In this partially advanced position, the scope 12 has a view of the suction head 60 as well as the tissue ahead of the suction head 60 .
[0114] It may be desirable for the endoscope to be spaced a distance radially from the surface of the suction head 60 . Such spacing allows for the endoscope image to be less “blocked” by the presence of the suction head, facilitating more precise placement of the suction head against the desired body tissue. For bladder applications, and in the case where the endoscope has a 25-35 degree viewing angle, and is in the diameter range of about 2.5 to 3 mm in diameter, and where the suction head is in the range of about 4.5 to 5.5 mm in width, the spacing is preferably about 0.25 to 0.75 mm, although more or less is also contemplated. Greater spacing, while further minimizing the amount of blocked view of the suction head 60 , also forces the overall device diameter to become larger, which is undesirable in applications where overall device profile is desired to be smaller, such as the bladder, where the device is inserted into the urethra.
[0115] The device distal end 24 also may include a tube holder 94 . The tube holder 94 is a housing that may be used to connect the various tubes/channels of the treatment device 20 , as shown in FIG. 10 . The tube holder 94 secures the endoscope tube 16 , the suction tube 17 , and the electrode tubes 52 . This arrangement of the tubes, with a non-circular outer shape, allows the distal portion of the treatment device to contain all the tubular elements in a desired arrangement, while minimizing the overall periphery dimension, thus facilitating placement of the device into anatomy such as the urethra to access the bladder.
[0116] The aforementioned embodiments, and those additional embodiment described below, may be useful to perform various procedures and methods of the invention. For example, the embodiments may be used to treat bladder conditions such as Over-Active Bladder (OAB).
[0117] In this regard, FIG. 17 is a side view showing the female anatomy, including the bladder B, the uterus UT, the vagina V, and the urethra U. The trigone region T is shown in the dashed region. FIG. 18 shows an angled frontal-axial sectional view of the bottom portion of the bladder B, including the trigone region T, the ureteric ostia O, the bladder neck N, and the urethra U. While use of one of the device embodiments of the present invention is described in connection with the female anatomy, the same or similar device is contemplated for use in the male anatomy as well. Some design alterations may be used, including lengthening portions of the treatment device, and/or making the device more flexible and/or deflectable.
[0118] Treatment device 20 may be first inserted into the urethra and into the bladder, as shown in FIG. 19 (note that for purposes of simplicity, the camera and light cable are not shown connected to the endoscope 12 , nor are the suction and infusion tubes or devices shown hooked up the ports). The endoscope 12 is preferably positioned nearer the distal end of the suction head during this step. The treatment device 20 and endoscope 12 may be inserted directly into the urethra, or may be placed through a prior positioned tubular sheath (not shown).
[0119] If the target tissue is the trigonal region of the bladder, it may be desirable to initially identify one of the ureteric ostia. The ostium may be marked ahead of time by placement of a guide wire, a suture loop, or may be just visualized during the placement of the treatment device, with care to avoid placement of the treatment device at or too close the ostium. In a preferred method, the tip of the suction head is placed just medial to the uretic ostium. In another embodiment, the suction head is placed just inferior to the uretic ostium. In both cases, the ureter itself is protected since as the ureter travels lateral and superior away from the visible ostia, placements medial and inferior avoid the obscured ureter.
[0120] The suction head 60 is placed onto the surface of the bladder tissue and the suction is activated, causing the surface tissue of the bladder to come into intimate contact with the face of the suction head, as shown in FIG. 20 . Use of movement stabilization devices connected to the handle are contemplated, for example, it may be beneficial to stabilize the position of the treatment device after the suction is activated and the tissue engaged with the suction head.
[0121] Though not shown, the tissue may actually protrude within the apertures on the suction head 60 . The suction engages and holds secure the tissue relative to the treatment device. Once the tissue is firmly secured to the suction head 60 , the endoscope 12 is preferably withdrawn to a point where the scope tip is closer to the proximal end of the suction head 60 . This facilitates observation of the cannula advancement step. The endoscope 12 may also be retracted just after the suction head tip 70 is placed near the ostium, but before the suction is applied to the tissue.
[0122] The cannulas 58 are now advanced into the tissue, seen in FIG. 21 , below the surface as prescribed by the offset distance of the cannula tubes 52 to the face 62 of the suction head 60 . The cannulas 58 of the electrode sets 54 may be activated by passage of electric current between them, which heats and ablates the tissue surrounding them and in between them, resulting in a heat affected zone 100 . The heat-affected zone 100 is preferably concentrated at a depth in the tissue. It is believed that afferent nerves emanating from the bladder trigone may be ablated to lessen the sensory signals driving overactive bladder.
[0123] In one preferred embodiment, the chosen depth of the heat-affected zone 100 is sufficient to protect the superficial layers of the bladder, such as the mucosa, from damage. In another preferred embodiment, the chosen depth is chosen to target superficial layers such as the suburothelium.
[0124] Preferably the electric current is in the radio-frequency range, and preferably it is delivered in a bi-polar fashion between the two electrodes. However, it is also contemplated that the two electrodes could form a mono-pole, and electric current could pass from them to a grounding pad, in a monopolar fashion. It is also contemplated, that a single electrode be utilized as a monopolar current source.
[0125] Multipolar configurations are also contemplated, either as single cannulas that are multipolar along their lengths or as multiple cannulas (3 or more) that are multiplexed or powered such that they operate in bi-polar modes, but possible in shifting patters. i.e., three cannulas that form 2 bipolar pairs (middle cannula is the common).
[0126] Once the treatment of the target location is performed, the suction may be released by venting the suction head 60 to atmosphere, the treatment device 20 may then be positioned in a different target location, and another ablation step may be performed, and repeated as many times as may be necessary to treat the bladder.
[0127] A number of different ablation patterns may be considered for treatment of the bladder. Such patterns are shown in FIGS. 22-31 . Note that the patterns are shown relative to the surface, but are intended to be submucosal, as described above. The size of any one ablation zone may be affected by the device size, and the cannula diameter and exposed length, the spacing between the cannulas, the depth of the cannulas from the suction head face, and electrical parameters such as current, frequency, “on time”, and other variables.
[0128] One aspect of the desired pattern may be simply the size of each ablation zone. A single ablation zone may be adequate if the size is large enough. However, a device that can yield a large ablation size may be too large for simple passage through the urethra. A device small enough to easily pass through the urethra may gain from multiple ablation zones, such as shown in FIG. 22 . Here, three relatively parallel and evenly spaced zones 100 are created with three placement steps. A first zone 100 a may be near one of the ostia O, a second zone 100 b may be near the other ostium O, and a third zone 100 c may be near the middle of the trigone T.
[0129] More or fewer ablation zones 100 are also contemplated, for example five, as shown in FIG. 23 . While many of the nerves associated with OAB are believed to reside in the trigone, some may be lateral to the ureteric ostia, and as such ablating regions of the bladder lateral to or posterior to the ostia may be of further benefit, as illustrated in FIG. 24 .
[0130] In addition to relatively parallel spacing of the ablation zones 100 (which may be performed by lateral manipulation of the treatment device, as the urethra and bladder are relatively soft pliable structures), it may be easier for the physician to pivot or pan the treatment device between ablation steps, resulting in a “fan shaped” pattern as shown in FIG. 25 .
[0131] The nerves emanating from the trigone that are associated with OAB are further believed to coalesce near the ureteric ostia. FIG. 26 shows multiple concentrated ablation zones 100 near the ostium O.
[0132] It is further contemplated that the distal portion of the treatment device, with the suction head and distal portions of the electrode tubes could be laterally articulable, and allow for more angled ablation zones 100 , as illustrated in FIG. 27 . Such an embodiment may be used with a flexible and articulable endoscope. Such angled or relatively horizontal ablation zones may be combined with more vertical ablation zones and/or fan shaped zones as described above.
[0133] FIG. 28 shows a fan-shaped pattern of relatively narrow ablation zones 100 . The fan-shape results from pivoting the device between ablations, as opposed to translating the device. A high number of zones 100 is created ( FIG. 28 shows five but more are possible). The zones 100 preferably avoid going lateral of the ureteral ostia O.
[0134] FIG. 29 shows a pattern of ablation zones 100 that avoids the inter-ureteric bar—the horizontal ridge between the ureteral ostia O. The zones 100 are shortened sufficiently to accomplish this goal.
[0135] FIG. 30 shows a pattern of ablation zones 100 that encompasses both a fan-shape as well as avoiding the inter-ureteric bar. Again, the zones 100 are shortened sufficiently to avoid the inter-ureteric bar.
[0136] FIG. 31 shows a pattern of ablation zones 100 that is similar to the pattern shown in FIG. 26 but avoids the lateral burn to minimize the chance of causing trauma to the ureteral ostium O. This pattern may include other zones. The zones 100 shown in this Figure merely highlight those closest to the ostium O.
[0137] Making shorter ablation zones 100 may be accomplished using an electrode cannula having a shorter length of exposure L between the tip of the cannula 58 and the end of the insulation 59 . FIGS. 32 and 33 show similar zone patterns except that the zones 100 in FIG. 32 are shorter than the zones 100 shown in FIG. 33 . The zones 100 in FIG. 32 were made by a device shown in FIG. 34 having an exposure length L 1 of approximately 10 mm. The zones 100 in FIG. 33 were made by a device shown in FIG. 35 having an exposure length L 2 of approximately 15 mm.
[0138] As mentioned above, it may be desirable to create the ablation zone in the submucosal tissue, so as to spare the surface tissue and urothelium to minimize follow-up patient discomfort, risk of infection, and other benefits. In the treatment device embodiments described above, e.g. such as the embodiment shown in FIG. 10 , the offset of the electrode tubes 52 from the face 62 of the suction head 60 influences the overall height/profile of the treatment device. Depending on the desired tissue depth for ablation, the height/profile of the treatment device could be larger than desired. An alternative embodiment that allows for relatively deep tissue depth, but minimizes impact on device profile is illustrated in FIGS. 36 and 37 .
[0139] The embodiment shown in FIGS. 36 and 37 utilizes electrode sets/cannula 54 that may be pre-shaped to incorporate a curved design, for example, having an “S” shape near their distal ends or a general arcuate shape. When the electrodes 54 are advanced from the electrode tubes 52 , they will angle down from the tube axis, thus embedding in tissue below the tube axis. This allows for the electrode tubes 52 to have a smaller offset distance from the face 62 of the suction head 60 , which further allows for the treatment device 20 to have a smaller height/profile. Such cannula may be formed from an elastic material such as super elastic nickel titanium alloy, or other shapeable but elastic conductive materials.
[0140] Another embodiment that facilitates a lower profile/height device in the portion that passes through the urethra is illustrated in FIGS. 38-42 . In contrast with the embodiment of FIGS. 7-9 , where the endoscope channel or tube 16 extends alongside and parallel to the suction channel or tube 17 , the alternative embodiment includes an endoscope tube 16 that resides at an angle α to the suction tube 17 , and to the side of the suction tube. The endoscope tube may be cut along a plane near the top portion of the suction tube, so as to minimize the height of the treatment device. This is best illustrated in the section views 40 through 42 .
[0141] At location 42 , the suction tube 17 periphery is fully intact. To further minimize overall profile from side-to-side, the endoscope tube 16 may be “nested” into the suction tube 17 as shown, and the suction tube 17 may be ovalized to narrow the width. Proceeding distally on the treatment device, at section 43 , the endoscope tube 16 resides higher within the suction tube 17 , and the upper portion of the endoscope tube 16 is exposed, which maintains the vertical height of the treatment device in this area. Further distally, at section 44 , the endoscope tube 16 rests even higher within the suction tube 17 , and more of the endoscope tube 16 is exposed. Further distally there is not endoscope tube 16 , as the endoscope 12 would project distally without any tubing surrounding it, as seen in FIG. 39 , where the endoscope has been placed and extended above the distal aspect of suction head 60 .
[0142] In use, this embodiment may be advanced “blindly” into the urethra until the suction head 60 is within the bladder, with the endoscope residing proximally, in the fully enclosed portion of the endoscope tube. This distal portion 92 of the device ( FIGS. 40-42 ) is lower in profile than the comparable portion of the embodiment of FIGS. 7-9 , as there is no endoscope tube nor endoscope in this portion during this delivery step.
[0143] At this point, the endoscope 12 can be advanced into the bladder and above the distal aspect of the suction head 60 . Note also that the endoscope tip may be substantially spaced above the suction head 60 , improving visualization, which may benefit the accurate placement of the suction head tip 70 relative to the ureteric ostia O.
[0144] FIG. 43 illustrates a further embodiment of a treatment device 20 having a lower profile/height in the portion that extends into the urethra. Similar to the embodiment of FIGS. 38-42 , this embodiment positions the endoscope 12 at an angle relative to the elongate shaft portion 26 of device 20 .
[0145] Treatment device 20 includes an elongate suction tube 17 extending to the distal portion 92 and suction head 60 . In this embodiment, the endoscope tube 16 , is at an angle α ( FIG. 46 ) to the suction tube 17 . A handle assembly 30 may be connected to the proximal ends of these tubes to hold them relative to each other. An optional sliding tube 40 may be incorporated into the handle assembly 30 for connection of the endoscope 12 to the treatment device 20 , similar to the sliding tube 40 described in previous embodiments. A sliding mechanism, which may be similar to the sliding mechanism 34 shown in FIGS. 4 a and 5 a and described above, may further be included to facilitate controlled advancement of the endoscope 12 relative to the treatment device 20 . A connection hub 150 secured to the treatment device 20 proximal of the distal portion 92 preferably contains one or more receivers 38 to receive one or more electrode sets 54 (see, for example, FIG. 4 a ). One or more suction ports 36 may also be connected to the handle assembly 30 , and are in fluid communication with the interior of the suction tube 17 , for either irrigation, suction, and/or venting of the interior of suction tube 17 and suction head 60 .
[0146] FIG. 44 is a bottom view of the treatment device 20 , which shows the face 62 of the suction head 60 . The suction head 60 is shown as including a plurality of apertures 66 leading to a suction chamber 68 . These features are best seen in FIG. 45 , which is a blow-up of area 45 showing the distal portion 92 of treatment device 20 .
[0147] FIG. 46 a is a longitudinal section view of the distal portion 92 of treatment device 20 . Here it can be seen that the endoscope tube 16 has a longitudinal axis 153 that extends at an angle α to the face 62 . It is to be understood that the endoscope tube 16 may be curved, in which case the angle α is measured to the longitudinal axis 153 at the opening 152 . This may be described more accurately as measuring the angle between a tangent of a curved longitudinal axis at the opening 152 and the face 62 .
[0148] The angle α is in the range of 1 to 20 degrees. The angle α may vary depending on the intended application. For example, when performing procedures via a relatively long urethra, a shallower angle α may be desired, for example in the range of 4 to 10 degrees. For female urethras of average length, good results have been achieved with an angle α of 6 to 8 degrees.
[0149] FIG. 46 b shows an embodiment where the suction face is tilted forward. It is envisioned that such an embodiment may include a suction face 62 that is tilted forward 5 to 10 degrees or more. If a tilted suction face 62 is employed, angle α may increase, or an endoscope tube 16 may be used that is parallel with the suction tube 17 .
[0150] The distal opening 152 of the endoscope tube is preferably flush with the exterior surface of the suction tube 17 and tube holder 94 , if present, so as to maintain a relatively low profile and smooth exterior surface to ease passage of the treatment device 20 into the urethra and into the bladder, when the endoscope 12 is in a retracted position.
[0151] FIG. 47 is a side view of the treatment device 20 , with identifying locations of axial cross sectional views, 48 - 50 .
[0152] FIG. 48 is a section view taken along section lines 48 - 48 of FIG. 47 and is just proximal of where the endoscope tube 16 intersects with the suction tube 17 , at 170 . Also visible here are the cross-sectional faces of the electrode tubes 52 , which extend distally towards the tip. The endoscope tube 16 can be seen crossing the inside of the suction tube 17 further distally.
[0153] FIG. 49 is a section view taken along section lines 49 - 49 of FIG. 47 and is just proximal of where the endoscope tube 16 emerges from the upper surface of the suction tube 17 . Further distally in this view, an aperture 66 is visible in the heel portion 63 .
[0154] FIG. 50 is a section view taken along section lines 50 - 50 of FIG. 47 and is in the region of the device 20 where the endoscope tube 16 emerges to the outside. Portions of the wall of the endoscope tube 16 are removed, so as to provide a smooth and low profile surface to the distal portion 92 . Also seen in this figure is an aperture 66 , as well as the baffle 72 if present. Note that in this embodiment, there may not be a separate tube holder 94 as in some of the above described embodiments, but the suction tube 17 may be reshaped or have additional segments of differing shapes secured to it in the distal region. For example the shape may be more “squared off”, as is shown, to facilitate incorporation and alignment of the electrode tubes 52 , and to provide shape transition to the suction head 60 .
[0155] The portions of intersection 170 between the endoscope tube 16 and suction tube 17 may be welded or similarly connected to secure the tubes together and provide a hermetic seal therebetween.
[0156] FIG. 51 shows a system 10 with a treatment device 20 as described in connection with the embodiments shown in FIGS. 43 through 47 above, together with an endoscope 12 . In this figure, the endoscope is secured to the device 20 , and in a retracted position. Note that the profile of the distal portion 92 of device 20 is low profile, suitable for advancement through the urethra and into the bladder space. Once the device 20 is in the bladder, the endoscope 12 may be advanced ( FIG. 52 ), in order to view the placement of the suction head 60 in one or more desired locations, as described above in connection with the various embodiments described previously.
[0157] FIGS. 53 through 55 show an embodiment similar to embodiments described above, such as, for example, the embodiment described in connection with FIG. 14 . A positioning feature 160 , shown in this embodiment as a hoop, is attached near the distal end of the suction head 60 . Positioning feature 160 may be attached to the face 62 , and may be fabricated of any suitable material that can be secured to the face 62 . For example, the hoop 160 may be a metallic, such as stainless steel, and may be welded, brazed, soldered, or bonded to the face 62 with adhesive. Other materials are contemplated, including polymeric and elastomeric materials. For example, the hoop may be made of a flexible material to ensure that it is atraumatic. Though a hoop is shown, the positioning feature 160 may take the form of one or more pointers, cross hairs, a circle, a wedge, or any other shape useful in providing a visual guide.
[0158] The positioning feature 160 may be used to aid in the placement of the device 20 relative to the desired anatomy to be treated. For example, to position the suction head 60 in a desired position relative to a uretic ostium in the bladder, the positioning feature 160 may be visualized with an endoscope 12 and visually lined up with the ostium. This can help assure that when the electrodes 54 are extended into the tissue, they will end up a desired distance from the ostium, such that when they are activated, they don't adversely affect the tissue of the ureter or its ostium.
[0159] In one embodiment, when the ostium is viewed with the endoscope, and the ostium is centered within the positioning feature 160 , the hoop is sized such that the extended electrodes 54 are close but not at the ostial tissue.
[0160] The positioning hoop 160 may optionally be added to any of the above described embodiments of the treatment device 20 .
[0161] As mentioned above, in connection with the embodiments of FIG. 10 , a 30 degree downward looking angled endoscope may be preferable, as is an offset spacing of the endoscope above the suction head, to aid in accurate and relatively unobstructed positioning of the suction head. This is the case with a conventional Hopkins rod type of endoscope.
[0162] Alternatively, a flexible deflectable endoscope may be utilized, as shown in FIG. 56 . The treatment device 20 may be any of the above described embodiments, such as that described in connection with FIG. 10 , but utilizing a flexible deflectable endoscope 110 as shown. Once entry into the bladder has been made, the endoscope 110 is deflected to view in a downward direction, preferably a significant distance above the suction head, as shown. The viewing field 112 is indicated by the dashed line.
[0163] If a deflectable scope is used, the need for the offset of the endoscope tube as described in connection with FIG. 10 would not be as important, thus providing an opportunity to further lower the height of the treatment device.
[0164] Alternatively, an articulating endoscope 120 such as indicted in FIG. 57 may be utilized to enhance the visualization of the treatment device. One such articulating endoscope may have a side-facing camera 122 built into the deflecting tip portion. The height and angle of the image relative to the suction head may be altered by articulating the distal tip portion.
[0165] Although the invention has been described in terms of particular embodiments and applications, one of ordinary skill in the art, in light of this teaching, can generate additional embodiments and modifications without departing from the spirit of or exceeding the scope of the claimed invention. Accordingly, it is to be understood that the drawings and descriptions herein are proffered by way of example to facilitate comprehension of the invention and should not be construed to limit the scope thereof.
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A device and method that provides a minimally-invasive approach to performing treatments on soft tissue, such as that found in the bladder. The device is useful for manipulating tissue such that treatment tools can be inserted into the tissue at a controlled depth.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to sewing machines in general and more particularly to sewing machines having mechanisms to replenish the bobbin thread supply while the bobbin remains in place within the loop taker.
2. Description of the Prior Art
One form of prior known bobbin case included a thread control lever which prevented spillage of thread from the bobbin and which simultaneously placed a drag on the rotation of the bobbin case as the bobbin became filled. One problem associated with the prior known thread control lever is that it is susceptible to snagging and breaking the bobbin thread. Another problem is that the loop seizing beak of the loop taker rotates in a direction opposite that in which the thread control lever projects, thereby increasing the susceptibility of snagging the bobbin thread between a projection of the thread control lever and the wall of the bobbin case.
SUMMARY OF THE INVENTION
It is an object of this invention to provide a bobbin case for a lockstitch sewing machine that is manually threadable from any direction.
It is another object of this invention to provide a bobbin case having a thread control lever which is immune to snagging bobbin thread when a bobbin is replaced within the bobbin case.
The disclosed objects and other advantages of this invention are achieved by providing a bobbin case with a race formed in its wall in which partially resides a bobbin thread control lever having one extremity pivotally fastened to the bobbin case. The other extremity of the bobbin thread control lever has formed thereon a thread engaging shoe which is spring biased toward the bobbin and which acts to contain the wraps of thread placed on the bobbin as the bobbin becomes filled with thread during the bobbin refilling process. The extremity of the bobbin thread control lever containing the thread engaging shoe is tapered to form an obtuse angle with the wall of the bobbin case, thereby preventing thread from being trapped between the wall of the bobbin case and the thread control lever when a bobbin containing thread is manually placed within the bobbin case. The race formed in the wall of the bobbin case also partially shelters the free extremity of the bobbin thread control lever, thereby affording additional protection against the snagging of bobbin thread.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other objects of this invention will become evident from an understanding of the preferred embodiment which is hereinafter set forth in such detail as to enable those skilled in the art to readily understand the function, operation, construction and advantages of it when read in conjunction with the accompanying drawings in which:
FIG. 1 is a vertical cross sectional view of the loop taker of a sewing machine having a bobbin thread control lever constructed in accordance with the teachings of this invention applied thereto;
FIG. 2 is a top plan view showing the loop taker contained within the bed of a sewing machine;
FIG. 3 is a perspective view of a bobbin thread control lever constructed in accordance with the teachings of this invention;
FIG. 4 is a top plan view of a loop taker showing the path taken by the bobbin thread as it exits the bobbin case;
FIG. 5 is a top plan view similar to FIG. 4 showing how the bobbin thread control lever of this invention prevents the snagging of the bobbin thread; and
FIG. 6 is a top plan view similar to FIG. 5 showing the susceptibility of a prior known bobbin thread control lever to snagging the bobbin thread.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to the drawings, the invention is shown applied to a sewing machine of the type having a provision for rewinding thread on the bobbin while the bobbin remains in the loop taker. The construction and operation of such a bobbin rewinder is fully described in the U.S. Pat. No. 3,138,127 of June 23, 1964 to Ketterer, which is owned by the assignee of this invention.
FIG. 2 best illustrates a bed 12 of a sewing machine having a cavity 14 formed therein in which resides a loop taker shown generally at 16. The cavity 14 is enclosed by a throat plate 18 and a bed slide plate 20. FIG. 1 shows a needle 22 which reciprocates through an aperture 23 formed in the throat plate 18 and which carries with it a needle thread 24 which is concatenated with a bobbin thread 26 by the loop taker 16 to produce a lockstitch in a well known manner. A fabric to be sewn is moved past the needle 22 by a feed dog 28 which has a set of serrated teeth 30 and which rises through the throat plate 18 to cooperate with a presser foot 32 in a well known manner. The loop taker 16 is rotated in timed relation to the reciprocation of the needle 22 by a bevel gear 34 which drives a hollow vertical shaft 36 restrained in a bushing 38 which is journalled in the bed 12 of the sewing machine.
The loop taker 16 is formed with a cup-shaped body portion 40 having a wall 42 with an inner surface on which is formed an annular bearing rib 44. A bobbin case 46 having a wall 47 defining its periphery includes an annular raceway 48 which engages the annular rib 44 of the loop taker 16. The bobbin case 46 is restrained from rotation within a cavity 50 formed in the loop taker 16 by a bifurcated rotation restraining member 51 carried in the bed 12.
A thread carrying bobbin 52 having a circular upper flange 54 and a circular lower flange 56 whose diameter is smaller than the diameter of the upper flange 54 is supported within the bobbin case 46 by its upper flange 54 resting on a platform 58 formed in the bobbin case 46. The upper flange 54 of the bobbin 52 is connected to the lower flange 56 by a core 60. The bobbin 52 is constrained within the bobbin case 46 by an arm 62 which is pivotally journalled at one extremity to a wall 64 of the bobbin case 46 by a pin 66. A leaf spring 68 acts against the arm 62 to bias the distant extremity of the arm 62 against the bobbin 52. The distant extremity of the arm 62 has a depending ball 70 formed thereon which engages a depression 72 formed in the top flange 54 of the bobbin 52 to restrain the bobbin 52 within the bobbin case 46.
The mechanism described in this invention may be applied to a bobbin replenishment mechanism whose construction and operation is described in the aforementioned U.S. Pat. No. 3,138,127 of June 23, 1964 to Ketterer. The bobbin replenishment mechanism is more specifically constructed to include a bobbin winding member 74 which resides within the cup-shaped body portion 40 of the loop taker 16 and below the lower flange 56 of the bobbin 52. The bobbin winding member 74 is fastened to a rod 76 which freely resides within the hollow loop taker shaft 36. The rod 76 is rotatably fastened to a lever 78 by a fastener 80. The lever 78 may be arcuately rotated to elevate the rod 76 and the bobbin winding member 74 attached thereto in a manner which is more fully described in the aforementioned Ketterer patent. The lower extremity of the rod 76 has a pin member 82 rigidly fastened thereto, which engages the bevel gear 34 to impart a turning motion to the rod 76. The lower flange 56 of the bobbin 52 has an annular groove 84 formed therein in which is contained a depending wedge 86 which may be engaged by a pin 88 formed on the surface of the bobbin winding member 74 when the bobbin winding member 74 is elevated by the rod 76. The bobbin winding member 74 is engaged against the bobbin 52 and is rotatably driven with the loop taker 16 by the bevel gear 34. The bobbin 52 may thereby be replenished with bobbin thread 26 which will be consumed in the formation of lockstitches. The bobbin winding member 74 may be disengaged from contact with the bobbin 52 by arcuately rotating the lever 78 downwardly, thereby causing the rod 76 to move downward and lower the pin 88 of the bobbin winding mechanism 74 away from engagement with the depending wedge 86 formed on the lower flange 56 of the bobbin 52.
A bobbin thread control lever 90 which is contained within the bobbin case 46 is shown in FIG. 3. The lever 90 has a bore 92 formed at one extremity thereof for receiving a pivot pin 94. The other extremity has a thread engaging shoe 96 which is arcuately shaped to engage wraps of bobbin thread 26 contained on the bobbin core 60. The bobbin case 46 has a race 98 formed in the wall 64 thereof in which the pivoted extremity of the thread control lever 90 is retained with the pivot pin 94. The extremity of the thread control lever 90 which contains the thread engaging shoe 96 is biased away from the wall 64 of the bobbin case 46 by a spring 100 which resides in a slot 102 formed in the thread control lever 90. The thread control lever 90 extends across a gap 104 formed in the wall 64 of the bobbin case. A flange 106 extends from the thread control lever 90 away from the thread engaging shoe 96 and resides within a race extension 108 contained in the wall 64 of the bobbin case 46. The free extremity of the thread control lever 90 has formed thereon an oblique surface 110. FIG. 4 shows that the oblique surface 110 forms an obtuse angle with the wall 64 of the bobbin case 46, and that the most distant intersection of the flange 106 with the oblique surface 110 of the thread control lever 90 is always sheltered by the race extension 108, irrespective of the position of the thread control lever 90.
The thread control lever 90 cooperates with the bobbin winder mechanism during the bobbin thread replenishment process to prevent the bobbin 52 from being overfilled with bobbin thread 26. The bobbin winder mechanism is engaged by arcuately rotating the lever 78 upwardly in a manner which need not be recited for a full understanding of the present invention. The arcuate upwardly rotation of the lever 78 causes the rod 76 to move upwardly through the loop taker shaft 36 and elevate the pin 88 contained on the bobbin winding member 74 against the depending wedge 86 contained within the annular groove 84 formed on the lower flange 56 of the bobbin 52. The rotation of the bevel gear 34 thereafter imparts a turning motion to the bobbin 52 through the pin 88 which is carried on the bobbin winding member 74 and which is attached to the rod 76. As the bobbin 52 rotates, it withdraws thread from the needle thread supply in a manner more fully described in the aforementioned patent to Ketterer.
It will be apparent from FIGS. 1 and 2 that as thread is wound around the bobbin core 60 the outer wraps of thread will begin to approach the circumference of the lower flange 56 of the bobbin 52. The wraps of thread which are placed on the bobbin 52 will begin to engage the surface of the thread engaging shoe 96 of the thread control lever 90 as the bobbin 52 is filled, due to the location of the thread engaging shoe 96 with respect to the outer edge of the lower flange 56 of the bobbin 52. When the wraps of thread wound around the bobbin core 60 engage the thread engaging shoe 96, the back surface of the thread engaging shoe 96 will engage an annular rib 112 of the bobbin winding member 74. As the bobbin 52 continues to fill with thread, the drag imposed on the annular rib 112 by the thread engaging shoe 96 will increase, and will cause the speed of the sewing machine drive motor to decrease. The decreasing speed will act to warn the sewing machine operator to terminate the bobbin thread replenishing operation. The operation may alternatively be terminated automatically by a mechanism such as that more fully described in the aforementioned patent to Ketterer.
Once a bobbin 52 has been replenished with thread it may be removed from the sewing machine by arcuately rotating upwardly the arm 62 and lifting out the bobbin 52. The bobbin 52 will thereafter be available for sewing when the size and color thread with which it has been filled is required by the sewing machine operator. It will be appreciated by one familiar with the art of sewing that it is advantageous to retain several bobbins, each filled with thread of a particular size and color, for ready availability should they be needed during a sewing project. It will therefore be evident that a normal operation during the sewing process will involve replacing a bobbin. To that end, the thread control lever 90 will insure that the thread 26 of the refilled bobbin does not snag between the thread control lever 90 and the wall of the bobbin case 64.
A bobbin which has previously been refilled with thread may be placed in the bobbin case 46 by arcuately rotating upwardly the arm 62 and placing the bobbin 52 into the exposed cavity within the bobbin case 46. The arm 62 is thereafter arcuately rotated downwardly causing the depending ball 70 to engage the depression 72 in the bobbin 52. The bobbin thread 26 will thereafter rest on top of the thread control lever 90 as shown in FIG. 5 with its free extremity leading toward the aperture 23 where it will be available to be concatenated with the needle thread 24 in the formation of lockstitches.
FIG. 5 shows that the thread 26 may not lead directly from the bobbin 52 to the aperture 23, in which instance it is possible for the thread to contact the extremity of the thread control lever 90 which contains the oblique surface 110. Since the oblique surface 110 of the thread control lever 90 forms an obtuse angle with the wall 64 of the bobbin case 42, it will be apparent that the bobbin thread 26 will not be trapped between the free extremity of the thread control lever 90 and the wall 64 of the bobbin case 46 and will, therefore, be less susceptible to being severed during the sewing process.
FIG. 6 shows a bobbin case 114 having a prior art thread control lever 116 which does not incorporate the teachings of the present invention. It will be appreciated that the bobbin thread 26 has become trapped between the free extremity of the thread control lever 116 and a wall 118 of the bobbin case 114 and may be severed by the further withdrawal of bobbin thread 26 from the bobbin 52, thereby disrupting the manual threading process.
Modifications and variation, of the above described preferred embodiment may become evident to one skilled in the art in light of the above teachings. It is to be understood that variations may be made to the preferred embodiment without departing from the spirit and scope of the invention as defined in the appended claims.
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A bobbin case for a lockstitch sewing machine is disclosed which contains a thread control lever so constructed to allow the bobbin to be manually threaded from any direction without incurring the possibility of snagging the bobbin thread between the wall of the bobbin case and the thread control lever. One extremity of the thread control lever is pivotally mounted in a race formed in the wall of the bobbin case. The free extremity of the thread control lever, which is spring biased toward the bobbin, is shaped to form an obtuse angle with the wall of the bobbin case. Bobbin thread is thereby prevented from snagging between the bobbin case wall and the thread control lever.
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CROSS-REFERENCE SECTION
[0001] This application claims priority of provisional application 60/336,038 filed Nov. 2, 2001.
BACKGROUND OF THE INVENTION
[0002] As encoders have become more and more sophisticated and high precision, their setup and alignment has become more and more critical. Some encoders are completely sealed units and are thusly aligned and calibrated at the factory under ideal conditions. On the other hand, many other encoders, such as those sold by the assignee of the present invention, are delivered to customers as components or subsystems. There are several benefits of to this approach, however it does preclude full factory setup/alignment. Therefore, various means have been developed to aid customers during the installation and setup of this class of encoder.
[0003] Typical early attempts at helping customers set up these encoders comprised not much more than providing a set of test points in the electronics and a systematic written procedure to follow. More recently, various sensing circuits have been included in the encoder electronics that provide some indication of proper alignment and/or inform the user about calibration adjustments.
[0004] The prior art alignment aids do not provide any automatic calibration features. At best they seem to give a general indication of signal strength (i.e., is the electrical sinusoid too weak or too strong). For optimal operation, the relative phase between the quadrature signals should be as close to 90 degrees as possible, their relative gains should be equalized, and their individual offsets should be set to zero. To the extent possible, these calibration operations should be transparent to the user (that is, not require the user to make fine electrical adjustments).
[0005] In addition to these calibrations, modern encoders also have index (or reference) marks. The output index pulses should occur every time the scale is in the same position relative to the encoder head. Thus another problem addressed by this invention is the need to calibrate the index pulse generation system such that the index pulse is generated at the same scale location to within an LSB of the encoder measurement.
SUMMARY OF THE INVENTION
[0006] Circuitry and firmware logic built into the processing unit allow a user to quickly setup an encoder by simply running the encoder scale under the head a few times. Indicator lights on the connector notify the user of processor and encoder status.
[0007] During the self-calibration cycle the encoder processor can automatically adjust itself in terms of amplifier gain and offset and signal quadrature phase shift. Also, the disclosed method automatically places the index pulse near the center of the index window with a 1 LSB repeatability with respect to the “zero-location” fringe. Also, the disclosed apparatus communicates its status to the user with a simple LED display so all of these operations are performed without external test or monitoring equipment.
[0008] In one aspect, the invention provides a method of calibrating an optical encoder of the type that generates two analog quadrature signals, x, y. The method includes a step of generating a plurality of digital samples, x i , y i , of the analog signals x, y, i having integer values from one to an integer n larger than one. The method also includes generating a plurality calibrated samples X i , Y i , according to the equation,
X i = ( x i + Ox i + P i × y i ) × Gx i
Y i = ( y i + Oy i ) × Gy i ,
Gx i and Gy i being scaling coefficients, Ox i and Oy i being offset coefficients, and P i being phase coefficients. The method also includes generating a plurality of magnitude M i , and phase, Φ i , samples according to the equations
M i ={square root}{square root over (X i 2 +Y i 2 )}
Φ i = ATAN [ Y i X i ] ,
M i and Φ i defining one sample of a phasor V i , according to the equation
V i =M i exp( jΦ i ),
j being the complex number square root of negative one. The phasor V i may be represented by a line segment in a two-dimensional coordinate system. The phasor has a first end and a second end. The first end lies at the origin of the coordinate system. The second end is displaced from the first end by a length equal to the magnitude M i , in a direction defined by an angle relative to the x axis equal to the phase Φ i . The method also includes providing initial values for the scaling coefficients, Gx 1 and Gy 1 , the offset coefficients, Ox 1 and Oy 1 , and the phase coefficients, P 1 . The method also includes adjusting the values of the scaling coefficients, the offset coefficients, and the phase coefficients so that
Gx i+1 equals either Gx i or Gx i plus or minus an incremental adjustment, Gy i+1 equals either Gy i or Gy i plus or minus an incremental adjustment, Ox i+1 equals either Ox i or Ox i plus or minus an incremental adjustment,
Oy i+1 equals either Oy i or Oy i plus or minus an incremental adjustment, and
P i+1 equals either P i or P i plus or minus an incremental adjustment.
[0015] The incremental adjustments to the coefficients are made so as to move the second end of the phasor closer to a circle of predetermined radius (such as a unit circle) centered about the origin of the coordinate system. More specifically, the incremental adjustments to the coefficients may be made so that a distance between the second end of a hypothetical phasor V′ i and the unit circle is less than or equal to a distance between a second end of the phasor V i and the circle. The hypothetical phasor V′ i is determined by the following equations:
X′ i =( x i +Ox i+1 +P i+1 ×y i )× Gx i+1
Y′ i =( y i +Oy i+1 )× Gy i+1
M′ i ={square root}{square root over (X′ i 2 +Y′ i 2 )}
Φ i ′ = ATAN [ Y i ′ X i ′ ]
V′ i =M′ i exp( jΦ′ i ).
[0016] In one alternative of the method, the coefficients Gx i and Ox i , may be adjusted once while V i lies in one half of the circle, and may not be adjusted again until V k lies in the other half of the circle, k being greater than i. In another alternative, the coefficients Gx i and Ox i , may be adjusted once while V i lies in the left half of the circle, and may not be adjusted again until V k lies in the right half of the circle, k being greater than i. In another alternative, the coefficients Gy i and Oy i , may be adjusted once while V i lies in one half of the circle, and may not be adjusted again until V k lies in the other half of the circle, k being greater than i. In another alternative, the coefficients Gy i and Oy i , may be adjusted once while V i lies in the upper half of the circle, and may not be adjusted again until V k lies in the lower half of the circle, k being greater than i. In another alternative, the coefficient P i may be adjusted once while V i lies in a quadrant of the circle, and may not be adjusted again until V k lies in a different quadrant of the circle, k being greater than i. Also, the values of the coefficients may be adjusted according to the following table:
Angle (in degrees) Angle (in Magnitude > unit circle radius Magnitude < unit circle radius From: degrees)To: Space Offset Phase Gain Offset Phase 348.75 11.25 0 Gx = Gx − 1 Ox = Ox − 1 — Gx = Gx + 1 Ox = Ox + 1 — 11.25 33.75 1 33.75 56.25 2 — — P = P − 1 — — P = P + 1 56.25 78.75 3 78.75 101.25 4 Gy = Gy − 1 Oy = Oy − 1 — Gy = Gy + 1 Oy = Oy + 1 — 101.25 123.75 5 123.75 146.25 6 — — P = P + 1 — — P = P − 1 146.25 168.75 7 168.75 191.25 8 Gx = Gx − 1 Ox = Ox + 1 — Gx = Gx + 1 Ox = Ox − 1 — 191.25 213.75 9 213.75 236.25 10 — — P = P − 1 — — P = P + 1 236.25 258.75 11 258.75 281.25 12 Gy = Gy − 1 Oy = Oy + 1 — Gy = Gy + 1 Oy = Oy − 1 — 281.25 303.75 13 303.75 326.25 14 — — P = P + 1 — — P = P − 1 326.25 348.75 15 if Magnitude = unit circle radius then no coefficients are adjusted wherein the increment value “1” is one least significant bit.
[0017] In another aspect, the invention provides method of processing signals generated by an optical encoder. The method includes generating samples of phase, Φ i , according to the equation
Φ i = ATAN [ Y i X i ] ,
where X i and Y i are samples of quadrature signals received from the encoder, and where i is an integer having values from one to an integer n.
[0018] The method also includes generating a count. The count increases by one every time the phase, when measured modulo two pi, crosses from a fourth quadrant of a unit circle to a first quadrant of the unit circle. The count decreases by one every time the phase, when measured modulo two pi, crosses from the first quadrant of the unit circle to the fourth quadrant of the unit circle. The fourth quadrant extends from angles 3/2 pi to 2 pi. The first quadrant extends from angles zero to pi/2. The method also includes generating two burst output signals in A quad B format by: generating an integer number representative of the count and the phase Φ i ; generating a running sum by counting transitions in the A quad B burst output signals, using known standard methods of counting transitions in A quad B format signals; generating a signed difference value representative of a difference between the integer number and the running sum; and generating transitions in the A quad B burst output signals until the signed difference value is zero.
[0019] In this method, the samples of phase Φ i may be represented as binary numbers having Dmax bits, Dmax being a pre-determined integer. The integer number may be represented as a binary number having d bits, d being a pre-determined integer. The integer number has D least significant bits and d minus D most significant bits, D being a user selectable integer that is greater than zero, less than d, and less than Dmax. The integer number may be generated by setting the D least significant bits of the integer number equal to the D most significant bits of the phase Φ i , and by setting the d minus D most significant bits of the integer number equal to the d minus D least significant bits of the count. Alternatively, D may be the smallest integer satisfying the equation D≧Dmax+log(S)/log(2), where S is a user selectable scale factor. The method may include generating a scaled phase Θ i , equal to a product of the phase Φ i and the user selectable scale factor S. The integer number may be generated by setting the D least significant bits of the integer number equal to the D least significant bits of the scaled phase Θ i , and by setting the d minus D most significant bits of the integer number equal to the d minus D least significant bits of the count.
[0020] In another aspect, the invention provides a method of generating an index signal for an optical encoder. The encoder generates quasi-sinusoidal quadrature signals indicative of a position of a scale relative to a sensor head. The encoder also generates a window signal. The window signal is characterized by a high value whenever an index mark of the scale is aligned with the sensor head. The window signal being characterized by a low value whenever the index mark is not aligned with the sensor head. The method includes setting a first number equal to the value of the phase when the window signal transitions from a low value to a high value; and setting a second number equal to the value of the phase when the window signal transitions from a high value to a low value. If a difference between the first number and the second number is greater than pi and less than 3 pi, then a phase index may be set equal to value that is between the first and second numbers. The method includes generating the index signal whenever the window signal is characterized by a high value and when the phase is substantially equal to the phase index. The phase index may be set equal to a median value between the first number and the second number. The steps of recording the phase values when at transitions of the window signal and of setting the phase index may be performed only after receipt of a calibration command. An indication to a user may be provided when the window signal is characterized by a high value. The indication to the user may be provided by activating a light source.
BRIEF DESCRIPTION OF THE FIGURES
[0021] FIG. 1 shows a block diagram of encoder processing electronics constructed according to the invention.
[0022] FIG. 2 shows a block diagram of the phase processor shown in FIG. 1 .
[0023] FIG. 3 illustrates calibration adjustments made according to the invention.
[0024] FIG. 4 illustrates calculation of an index point according to the invention.
[0025] FIG. 5 shows a block diagram for calculating the index point according to the invention.
[0026] FIGS. 6A and 6B show top and side views, respectively, of connectors housing processing electronics constructed according to the invention.
[0027] FIG. 7 illustrates A quad B signals and an index pulse.
[0028] FIG. 8A illustrates motion of a scale in an encoder.
[0029] FIGS. 8B and 8E illustrate sine and cosine signals, respectively, generated by an encoder.
[0030] FIGS. 8C and 8F illustrate the A and B, respectively, portions of an A quad B signal generated by an encoder.
[0031] FIGS. 8D and 8G illustrate the A and B, respectively, of a burst A quad B signal generated according to the invention.
[0032] FIG. 9 shows a block diagram of a method for generating the signals shown in FIGS. 8D and 8G according to the invention.
[0033] FIG. 10 illustrates a method according to the invention by which the user interface logic communicates with the user.
DETAILED DESCRIPTION OF THE INVENTION
[0034] FIG. 1 shows an optical encoder system 10 comprising a sensor head 50 that observes the relative motion of a scale 60 and associated signal processing electronics 100 . As discussed below, the processing electronics 100 automatically calibrates the encoder's position measuring circuits and index pulse generating circuits. The electronics 100 are preferably implemented in a miniaturized form factor that includes firmware programmable logic, however, other implementations of the electronics 100 are embraced within the invention.
[0035] The Sensor Head
[0036] The sensor head 50 and scale 60 preferably cooperate in a known fashion to produce two families of signals. One family of signals provide information about the displacement of scale relative to the sensor head. These signals are the quadrature signals 70 . The second family of signals is the index window signals 80 ; these signals indicate when a specific location on the scale 60 passes by the sensor head 50 .
[0037] In one preferred implementation the analog quadrature signals internal to the sensor head 50 have a generally sinusoidal strength variation that is related to the displacement of the scale 60 . These “x” and “y” signals are ideally shifted from one another by 90 degrees of phase. These analog signals are typically sampled and converted to digital values in sensor head 50 by Analog-to-Digital converter 55 ; the digital output values 70 are denoted by “x i ” and “y i ” respectively in FIG. 2 , where the subscripted “i” indicates that these values are sampled values. As shown in FIGS. 1 and 2 , signals 70 are transmitted to phase processor 101 where their instantaneous phase, among other things, is determined. FIG. 2 shows a block diagram of the phase processor 101 , the functional modules of which are described below.
[0038] Autonomous Calibration
[0039] The sampled values pass into calibration module 115 that applies Scaling (Gx i and Gy i ), Offset (Ox i and Oy i ), and Phase (P i ) calibration values using the formulae:
X i =( x i +Ox i +P i ×y i )× Gx i
Y i =( y i +Oy i )× Gy i (1)
where X i and Y i are the postalibration quadrature signals 73 . Similar formulae have been used in the prior art. These alternative formulae did not converge properly under all conditions and/or failed to accommodate the Phase calibration values. Formulae (1) are preferably combined with the incremental Coefficient Generator 155 discussed below to achieve proper convergence of the calibration values under all initial and subsequent conditions.
[0040] Collectively, the Scaling, Offset, and Phase calibration values arrive at circuitry 115 as Calibration Values 77 as shown in FIG. 2 . In the preferred embodiment, the calibration circuitry 115 is implemented along with all other parts of the phase processor shown in FIG. 2 in a field programmable gate array (FPGA) using a firmware program stored in non-volatile memory (not illustrated) within the processing electronics 100 . In the figure the various processing functions are shown as separated blocks for clarity only. Of course, a less integrated phase processor is also embraced within the invention.
[0041] Phase Estimator
[0042] Post-calibration quadrature signals 73 are processed in the phase estimator 125 to form estimates of the vector magnitude, M i 76 , and phase, Φ i 75 , of a phasor that corresponds to the two quadrature signals. The magnitude and phase estimates may preferably be generated using so called CORDIC mathematics. CORDIC mathematics is known in the prior art but other processing approaches could also be used.
[0043] The phase estimator accepts the two post-calibration signals 73 and evaluates the magnitude and phase according to the formulae:
M i ={square root}{square root over (X i 2 +Y i 2 )}
Φ i = ATAN [ Y i X i ]
[0044] These two processed values are distributed to several other modules within the processing electronics.
[0045] A sampled phasor corresponding to the magnitude and phase samples is defined by V i =M i exp(jΦ i ), V i being the phasor, j being the complex number square root of negative one.
[0046] Coefficient Generator
[0047] The Coefficient Generator functional module 155 uses the phase 75 and magnitude 76 values to adjust the calibration coefficients applied in the calibration module 115 . As shown in FIG. 3 and Table 1 below, the Coefficient Generator module 155 applies a series of logical tests to decide if the phasor 156 represented by the phase 75 and magnitude 76 lies on a unit circle 157 . If the phasor 156 is not on the circle 157 , the module increments/decrements the various calibration coefficients 77 until the phasor does lie on that circle. Each increment/decrement is preferably small, so the effect of any one adjustment to the calibration coefficients is nearly imperceptible.
[0048] The logical tests can be applied with a variety of rules. For example, the coefficient generator module 155 may apply the tests each time a sample phase is recorded. Alternatively, in the preferred implementation, the tests are only applied if the current phase angle of the phasor is in a different quadrant than the phase value at which the last adjustment was made to the calibration coefficients. This preferred mode prevents the same correction from being applied over and over again when the scale is not moving across the sensor head. Another alternative is to calibrate the sensor once, to accommodate manufacturing and/or initial set up effects, and then to lock those calibration values in for all future measurements (or at least until a recalibration command is applied).
[0049] The application of these tests is illustrated in conjunction with FIG. 3 , which shows an example of nearly pure positive x offset. FIG. 3 shows a unit circle 157 . Ideally, the magnitude Mi generated by phase estimator 125 is always equal to one (on the scale of the diagram of FIG. 3 ), so the endpoint of the corresponding phasor always lies on the unit circle 157 . However, calibration offsets can result in the phasors being displaced from the unit circle. FIG. 3 shows a case in which all generated phasors lie on the circle 158 which is displaced from the unit circle in the positive x direction. When the endpoint of the phasor generated by phase estimator 125 lies at point 1 (where the phase is about 10 degrees) the x value is too large (viz., outside the unit circle). In an attempt to move point 1 towards the unit circle, the module 155 reduces the gain, Gx i , incrementally and makes the offset, Ox i , slightly negative. At a later time, when the phase is noted to be about 180 degrees (point 2 in FIG. 3 ), the x value is too small (viz., inside the unit circle), so the module increases the gain incrementally and makes the offset a little more negative in an attempt to move point 2 out onto the unit circle. Module 155 preferably continues to adjust the calibration coefficients until such time as the phasor falls on the unit circle for all values of the phase. Note that in the example above the gain was alternately reduced and increased, netting to no change, while the offset was continually made more negative, properly correcting for the initial positive x offset.
[0050] Table 1 shows a preferred set of logical tests to be employed by module 155 . As shown in the first line of the table, if the phase value of the current phasor is between 348.75 and 11.25 degrees, and if the magnitude of the current phasor is greater than unity, then module 155 decrements the calibration scale factors Gx and Ox by one least significant bit. Table 1 shows the preferred tests and adjustments performed by module 155 for all values of phase and magnitude of the current phasor, however, it will be appreciated that other sets of tests and adjustments may be used as well.
TABLE 1 Coefficient adjustment logic Mag > unitR Mag < unitR AngleFrom: AngleTo: Space Offset Phase Gain Offset Phase 348.75 11.25 0 Gx = Gx − 1 Ox = Ox − 1 — Gx = Gx + 1 Ox = Ox + 1 — 11.25 33.75 1 33.75 56.25 2 — — P = P − 1 — — P = P + 1 56.25 78.75 3 78.75 101.25 4 Gy = Gy − 1 Oy = Oy − 1 — Gy = Gy + 1 Oy = Oy + 1 — 101.25 123.75 5 123.75 146.25 6 — — P = P + 1 — — P = P − 1 146.25 168.75 7 168.75 191.25 8 Gx = Gx − 1 Ox = Ox + 1 — Gx = Gx + 1 Ox = Ox − 1 — 191.25 213.75 9 213.75 236.25 10 — — P = P − 1 — — P = P + 1 236.25 258.75 11 258.75 281.25 12 Gy = Gy − 1 Oy = Oy + 1 — Gy = Gy + 1 Oy = Oy − 1 — 281.25 303.75 13 303.75 326.25 14 — — P = P + 1 — — P = P − 1 326.25 348.75 15 Note: angles in degrees note: if Mag = unitR then nothing is adjusted
[0051] Fringe Counter
[0052] The fringe counter module 137 , shown in FIG. 2 , identifies phase measurements in which a 2 pi boundary has been crossed. The sign bits from each set of calibrated quadrature signals 73 is sent to a fringe counter module 137 . These sign bits are well know indicators of the quadrant of the unit circle in which a phasor resides. Thus, the module 137 increments or decrements the fringe count each time the phasor (represented by signals 73 ) transitions from the fourth to the first quadrant or back respectively. The output of fringe counter 137 , the fringe count 78 , provides the higher order bits in the output word 150 , as described below.
[0053] Phase Output
[0054] The output signal from the phase processing electronics 101 can be either a digital word 150 (DW) or a pair of logic level pulse trains 151 , 152 , called A quad B (AQB) in the industry. This second format, shown in FIG. 7 , comprises two phase-shifted pulse trains 151 , 152 wherein each transition represents a phase change of one LSB. FIGS. 8 A-G show how the pulse trains are related to the underlying scale position and to the quadrature signals generated by the encoder head. For clarity, the AQB signals are illustrated with no extra interpolation; that is, each of the AQB signals switches between high and low states once per cycle of the quadrature signals 70 , allowing a position resolution of ¼-cycle.
[0055] FIG. 8A shows a hypothetical graph of scale motion, where the scale moves in one direction at a uniform velocity for a period of time, stops and waits, and then retraces its path. FIGS. 8B and 8E illustrate the quadrature signals 70 . Note that these signals appear as true sinusoids only because the scale movement has constant velocity. FIGS. 8C and 8F illustrate the industry AQB standard A and B signals. Position is determined by counting the transitions in the AQB signals. Every transition between states represents a single count (or LSB) change. The direction of motion is determined by simple combinatorial logic rules that examine the before and after transition states of the two signals. Finally, FIGS. 8D and 8G illustrate the AQB burst signals 151 , 152 as generated by the Burst Generator 137 of State Generator 135 of the present invention.
[0056] As shown in FIG. 2 , the State Generator 135 generates these output signals by combining the phase 75 and the fringe count 78 to create a single digital word 150 representing the total unwrapped phase from, some index location. The digital phase 75 forms the LSB's of the digital word 150 while the fringe count 78 forms the upper bits. Such a combination is well known in the art. The State Generator compares the new digital word 150 with the current AQB output state of Phase Processor 101 and controls the Burst Generator 137 to make the output state of burst signals 151 , 152 represent the digital word 150 .
[0057] FIG. 9 is a flow chart of the preferred implementation for generating AQB burst signals 151 , 152 from the State Generator 135 . State Generator 135 preferably contains an internal accumulator, Step 901 that maintains a running sum of transitions from Burst Generator 137 . The running sum is compared at Step 902 to the current measured digital output word 150 , Step 903 . Based on this comparison, the State Generator controls the burst generator 137 to update the number of transmitted pulses in burst signals 150 , 151 . If the comparison shows the values to be equal, then, of course, no change is required (Step 906 ). On the other hand, if there is a difference, then Burst Generator 137 (Step 904 ) is commanded to produce a high speed string of transitions on the burst signal lines 151 , 152 . The burst generator correctly encodes the sequence of transitions using AQB encoding; that is, it recreates the correct phasing of the A and B signals such that standard AQB decoders will properly interpret increases or decreases in total count. The AQB signals are fed back to the accumulator through a decoding circuit, Step 905 . When the running count in the accumulator equals the digital word 150 , the comparison at Step 902 turns off the Burst Generator 137 .
[0058] Returning to FIG. 8 , the operation of the burst generator 137 is shown in FIGS. 8D and 8G for the A and B signals respectively. Each of the vertical dashed lines indicate a time at which a digital phase sample is taken. Whereas in the conventional AQB signals the transitions occur synchronously with the changing phase of the quadrature signals 70 , in the burst signals 151 , 152 all of the transitions occur immediately after the digital samples are taken. As indicated by the bold arrows, each transition in the conventional AQB signals has a corresponding transition in the burst signals, ensuring that the accumulated count is correct.
[0059] As illustrated in FIG. 8 and suggested in FIG. 9 , the changes in the burst AQB output are initiated by the arrival of each new digital phase measurement 150 . It is possible, however, for the burst generator to still be running when the next measurement arrives (for example, if there had been a very large position change in the previous digital sample). The aforementioned feedback loop ensures that even under this “overrun” condition the AQB output will be able to “catch up” to the measured position, since the burst generator keeps running until the comparison at Step 902 is satisfied.
[0060] The State Generator 135 also incorporates the index information in the output stream(s). As shown in FIGS. 1 and 2 , the Index Logic 200 provides a single, digital Index Phase value 210 to the State Generator 135 . In the A quad B output mode a separate index output line 153 is provided. The State Generator 135 raises the index output line 153 to logic “high” during the time when the measured phase exactly equals the index value. That is, as shown in FIG. 7 , a one LSB long pulse 154 is transmitted during the burst of pulses that move the phase count from one side of the index to the other. Of course, the index output line 153 will remain high indefinitely if the scale happens to stop exactly on the index phase.
[0061] The State Generator can also accept a programming signal, not shown, which changes the apparent interpolation depth in the output 150 . The change in interpolation depth is accomplished by simply scaling the full interpolation depth output of the phase estimator 125 by the desired integer interpolation factor. For example, if the phase estimator's inherent interpolation depth is 10 bits (×1024) and the programming signal commands an “×200” output, the state generator effectively applies a 200/1024 factor to each digital output phase (binary scaling factors such as ×8, or ×16 are typically applied by simple bit shifting). Since the burst generator produces AQB signals to match the digital word, the digital scale factor applied in the State Generator is automatically applied to the AQB output as well.
[0062] Although both the digital word output 150 and the AQB output are produced by the State Generator, typically, only one of the two phase output formats (DW or AQB) is actually transmitted to the user, depending on customer preference. When the State Generator 135 is generating the digital word type output, only binary interpolation scaling is preferably applied to avoid fractional bits. The number of bits of resolution is preferably logic programmable and is typically between 8 and 12 bits. In the DW embodiment, the preferred digital output word 150 is a 32 bit word, with the higher order bits being supplied by the fringe count 78 . (Also in the preferred embodiment an additional 8 high order bits are provided to supply health and status information to make a 40 bit output word). In the preferred embodiment, this word is supplied to the user in bit-serial format.
[0063] In DW output mode the Index Phase value 210 can be used in at least three different ways. First, the fringe counter 137 can be set to zero every time the Index Phase is observed. Alternatively, the processor can be programmed to set the fringe counter to zero only at the first observation after power up. Thirdly, the State Generator can be programmed to internally subtract the Index Phase value from each and every measurement. In this latter configuration the digital output word 150 will read zero (0) whenever the index point is crossed. Alternatively, the Index Phase value 210 can be transmitted to the user to be used as he sees fit.
[0064] Index Pulse Set-Up and Generation
[0065] As shown in FIG. 1 , the second signal type produced by sensor head 50 is the index window signal 80 . This signal, as shown in FIG. 4 , is a logic level rectangular function that is preferably produced within the sensor head 50 itself by an ASIC 58 . The window signal Zw is typically at logic level low for most positions of the scale 60 relative to the sensor head 50 . However, when the index feature (not illustrated) on the scale reaches the sensor head, a special detector in the sensor head, combined with the internal ASIC, causes the Zw to rise to logic level high. If the scale continues to move past the sensor head, the index feature moves away from the sensor head and Zw returns to logic level low. As shown in FIG. 4 , the index feature and the sensor head detector are designed such that, under typical alignment and operational conditions the distance that the scale travels between the rising edge 81 of Zw and the falling edge 82 , is on the order of one optical fringe (i.e., the phase varies by approximately 360 degrees).
[0066] As indicated in FIG. 1 , the index window signal 80 , the phase value bits of output word 150 and a control signal 95 from the User Interface 300 are all applied as inputs to the Index Logic module 200 . In the preferred mode, only the lowest bits of fringe counter 137 are used in the Index Logic module 200 . In addition, in the preferred implementation, a portion of the processing of the Index Logic occurs in the aforementioned FPGA while other processing steps are performed by an included microprocessor chip. The control signal (which may also be supplied by an external computer through the computer interface 400 ) tells the module when to perform its function of developing and calibrating the index phase signal 210 .
[0067] Generally, the physical index indicator on the scale 60 has only enough resolution to identify one particular fringe. Users, however, require that the index location be identified as a particular phase value, Φ z , that is repeatable to within a single LSB. The exact phase value (between 0 and 2 pi) is not important but the repeatability of the value is.
[0068] The index window 80 is always related to a particular grating location (viz., a particular fringe) but it does not always start at any particular phase value nor is it always exactly one fringe long. Therefore, index phase value, which must be repeatable to within one LSB, cannot be selected a priori because that a priori value (between 0 and 2 pi) might be outside the index window or might appear twice, at each end of a long index window. Preferably, then, as shown in FIG. 4 , the index phase value should fall near the middle of the index window 80 to accommodate measurement to measurement variations in the locations of edges 81 and 82 . Since there is no fixed relationship between the index window 80 and the measured phase 75 (Φ i ), a calibration function should be performed (a) to ensure the window is the correct size and (b) to determine a suitably centered value for the index phase value Φ z 210 . This digital phase value ( 210 ) is supplied to the State Generator 135 as shown in FIG. 2 . In the preferred implementation, the index phase value 210 is calculated using a partially “unwrapped” digital phase 150 a extracted from the lower order bits of the full digital output word 150 . Typically, all of the phase processor bits and two fringe counter bits are used. As shown in FIG. 4 , the measured phase 75 has discontinuities between 2 pi to 0, as is well understood. The digital output phase 150 eliminates these discontinuities by tracking the fringe count. For the purposes of calculating the index phase the index logic only needs to keep track of the fringe count over three or four fringes, as shown in FIG. 4 , since the presence of the index window 80 gates the calculation to span at most three fringes.
[0069] The index logic module 200 performs these calibration functions autonomously using a method similar to the typical method diagrammed in FIG. 5 . As shown in the figure, the method typically includes the steps of:
1. Waiting until a “calibrate” command is present. <Step 501 > 2. Monitoring the index window signal. 3. Recording the phase Φ R for the rising edge 81 . <Step 502 > 4. Recording the phase Φ F for the falling edge 82 . <Step 503 > 5. Subtracting Φ R from Φ F to estimate index window size. <Step 504 > 6. Testing if index window is greater than 0.50 fringes and less than 1.50 fringes. [Return to step 2 if index window does not meet this criterion] <Step 504 > 7. Setting the index phase 210 at the mid-point of the index,window, viz. Φ z =(Φ F −Φ R )/2. <Step 505 >
[0077] Once the value of Φ z is set, the Index Logic 200 transmits the index phase 210 to the State Generator 135 in the Phase Processor 101 , as shown in FIG. 1 .
[0078] Note, of course, that the distinctions between various modules in the processing electronics 100 is made for clarity only; in the preferred implementation almost all of the processing electronics are part of a single FPGA or programmed into the included microprocessor.
[0079] Computer Interface
[0080] As shown in FIG. 1 the phase processing electronics 100 contain a computer interface module 400 . In the context of this invention this module performs the typical input/output functions one skilled in the art would expect, providing the pathways and handshaking required to allow back and forth communications, data and control flow between the processing electronics 100 and an external computer.
[0081] User Interface
[0082] The last module illustrated in FIG. 1 is the diagnostic user interface 300 . The preferred interface 300 , shown in FIG. 6 , comprises four light emitting diodes (LEDs) 312 , 314 , 316 , 318 (shown collectively in FIG. 1 as 310 ), of different colors and/or sizes, and a user operated push button switch 350 all connected to controller logic 380 . The logic 380 operates on the various signals produced by the phase processor 101 and the index logic 200 to control the LEDs 310 and it accepts the user's “index set-up” command in the form of a pressing of the push button switch 350 .
[0083] FIG. 10 illustrates the method 700 by which the user interface logic 380 communicates with the user. At power up, step 705 , the logic initializes itself and energizes the small, green Power LED 312 . The logic then compares the two unprocessed quadrature signals 70 with each other. Stripped of their sign bits, these signals provide an estimate of the magnitude of the phasor. It is easy to show that when |x i |=|y i |, |x i |=M i /1.414, so the logic 380 uses the value |x i | when |x i |=|y i | to select at step 710 the appropriate signal health indicator LED ( 314 , 316 , or 318 ). If the signal strength M i is above a previously defined “satisfactory” value, the green health indicator LED 314 is illuminated. If the signal strength is below the satisfactory value but above another previously defined “adequate” value the yellow health indicator LED 316 is illuminated. If the signal strength is below the adequate value, the red, warning, health indicator LED 318 is illuminated (this indicates for example that insufficient light is incident on the sensor head 50 ). Other indicator schemes could be used, as should be obvious to one of average skill in the art. Note that the “raw” signals 70 must be used, since all signals after the calibration module 115 will appear to have adequate magnitude, due to the action of the calibrator.
[0084] If at any time the user moves the index mark on the scale in front of the sensor head, step 715 , the logic turns off the signal health LED ( 314 , 316 , or 318 ) for short period of time, say 10 seconds. This “blink” is the indication to the user that the index mark has been observed. Should the user want to set (or reset) the index phase calibration, the user can initiate the calibration mode by pressing the push button 350 on the user interface 300 or by sending the equivalent command though the computer interface 400 . The user interface acknowledges the command, step 720 , by placing the Power LED 312 into a flashing mode. This flashing mode will remain in effect until such time as the index calibration is completed or the unit is de-powered. Internally, the user interface 300 sends a calibrate command to the Index module 200
[0085] Once the unit is flashing, the user completes the calibration by moving the index point in front of the sensor head once again. Again, the user is informed that the index window has been observed when the UI logic 380 blinks the signal health LED ( 314 , 316 , or 318 ) off for a short period of time. The index logic 200 autonomously estimates the index phase, Φ z , as was described above, in steps 725 through 740 . When an index phase has been successfully calculated, the UI logic returns the Power LED 312 to its normal continuous mode, step 750 . The user should move the index mark back and forth under the sensor head until the Power LED 312 returns to its normal continuous mode.
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The disclosed electronic processing apparatus calculates and applies calibrations to sensors that produce quasi-sinusoidal, quadrature signals. The apparatus includes either or both of fixed and programmable electronic circuits. The apparatus includes a circuit to calculate the phase and magnitude corresponding to the two input (quadrature) signals. The apparatus also includes a circuit for accumulating the number of cycles of the input signals. The apparatus also includes a circuit to generate Gain, Offset, and Phase calibration coefficients, wherein the circuit compares the phase space position of the measured phasor with the position of an idealized phasor, the locus of the idealized phasor in phase space being a circle of predetermined radius with no offset. The calculation of the coefficients occurs without user intervention, according to a pre-programmed rule or rules. The apparatus also includes a circuit to apply the Gain, Offset, and Phase calibration coefficients to the measured quadrature signals x i and y i according to the formulae
X i = ( x i + Ox i + P i × y i ) × Gx i
Y i = ( y i + Oy i ) × Gy i
where Gx i and Gy i are the scaling coefficients, Ox i and Oy i are the offset coefficients and P i is the phase coefficient and where X i and Y i are the post-calibration quadrature signals. The apparatus also includes a circuit that creates an output signal representative of the current, calibrated phase. The output signal is either a parallel, digital word or one or more serial pulse trains wherein the total number of pulses produced over time corresponds to the total phase change in the measured signal. The output signal is coded to allow phase decreases as well as phase increases.
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TECHNICAL FIELD OF THE INVENTION
[0001] The present invention relates to a textile product comprising an outer fabric and a flexible light-emitting display arranged behind the outer fabric, which flexible display has a diffusing element being arranged to receive and diffuse light emitted from the flexible display. The present invention also relates to a method for the manufacturing of such a textile product, and a flexible light-emitting display adapted for use inside a textile product.
BACKGROUND OF THE INVENTION
[0002] An example of such a textile product is disclosed in the document WO2004/100111, wherein a flexible display is incorporated in a garment, such as a shirt. A diffusing element is provided either on the flexible display itself or in the garment, namely in a pocket of the garment accommodating the flexible display, so as to diffuse light coming from two adjacent discrete light sources of the flexible display in order to produce a substantially continuous light display. Thus, a single diffusing element is used.
[0003] Another garment, namely a jacket, with a flexible display screen having light-emitting diodes (LEDs) thereon is disclosed in the document WO2006/014230. The flexible display screen is arranged directly behind an outer cloth of the garment, which outer cloth may act as an optical diffuser for the LEDs.
[0004] Both these prior art textile products utilize a single diffusing element. This may hamper the diffusing functionality, both in terms of limited overall diffusing effect and limited control of the diffusing effect. Also, the diffusing element disclosed in WO2004/100111 has a considerable thickness, which may cause the display's contours to be visible from the outside of the garment, even if it is turned off.
SUMMARY OF THE INVENTION
[0005] It is an object of the present invention to overcome or at least alleviate these problems, and to provide an improved textile product.
[0006] This and other objects that will be evident from the following description are achieved by means of a textile product, a method for the manufacturing of a textile product, and a flexible light-emitting display adapted for use in a textile product, according to the appended claims.
[0007] According to an aspect of the invention, there is a provided textile product comprising an outer fabric and a flexible light-emitting display arranged behind the outer fabric, which flexible display has a diffusing element being arranged to receive and diffuse light emitted from the flexible display, the textile product being characterized by a diffusing spacer fabric arranged adjacent to the outer fabric so as to receive and further diffuse light emitted from the flexible display, which diffusing spacer fabric is separate from the diffusing element.
[0008] The diffusing spacer fabric acts as a second separate diffusing element, and tuning the characteristics of the two diffusing elements, such as material, thickness, profile structure, shape, density, etc., allows for optimization of the light diffusing characteristics. For instance, two diffusing elements with different densities (similar or different materials) could be used to achieve desired diffusing characteristics. Moreover, two different fabrics like foam and needle padding with similar densities can still show totally different light emitting effects, which again allows for optimization of the diffusing characteristics.
[0009] Preferably, the diffusing spacer fabric is arranged between the flexible display and the outer fabric, so that the appearance and outer surface structure of the outer fabric is maintained. Alternatively, the diffusing spacer fabric could be attached outside of the outer fabric.
[0010] In one embodiment, the diffusing spacer fabric has a substantially larger area compared to the flexible display. For example, in case the textile product is a jacket, the area of the diffusing spacer fabric preferably matches that of the front or backside of the jacket, or that of any other piece of fabric of the textile product that the flexible display is attached to. The diffusing spacer fabric having the substantially larger area compared to the flexible display substantially prevents the contours of the flexible display from being visible from the outside of the textile product, so that the display is not revealed when it is its off-state.
[0011] In one embodiment, the diffusing spacer fabric has a greater thickness than the outer fabric. To this end, the diffusing spacer fabric is adapted to space the flexible display from the outer fabric.
[0012] In one embodiment, the textile product further comprises additional spacer fabric arranged around the flexible display. The thickness of the additional spacer fabric preferably matches that of the flexible display, so that the part of the textile product incorporating the flexible display gets a uniform thickness. This is especially advantageous in case the textile product is a garment, since the uniform thickness makes the garment more comfortable to wear for a user. The additional spacer fabric may further reduce the visibility of the contours of the flexible display from the outside of the textile product.
[0013] In one embodiment, the flexible display is arranged between the diffusing spacer fabric/outer fabric (depending on which one is farthest in) and an inner fabric. Here the flexible display (or any pocket accommodating the flexible display) can be attached to either the diffusing spacer fabric/outer fabric or the inner fabric, for example. In the latter case, the flexible display is preferably also attached to the diffusing spacer fabric/outer fabric, in order to maintain the distance between the flexible display and the diffusing spacer fabric/outer fabric so that the display performance is not altered and/or degraded.
[0014] In one embodiment, the flexible display comprises a flexible substrate having at least one light source mounted thereon, and a flexible thermo regulating layer is provided on the opposite side of the substrate compared to the side with the at least one light source for dissipating heat from the remaining display device. This allows for consistent operation and increased endurance of the display. Further, using a flexible thermo regulating layer allows the display to maintain its overall flexible nature.
[0015] In one embodiment, the textile product is a garment, such as a jacket, a vest, a sweater, or a shirt.
[0016] According to another aspect of the invention, there is provided a method for the manufacturing of a textile product comprising an outer fabric, the method comprising arranging a flexible light-emitting display behind the outer fabric, which flexible display has a diffusing element being arranged to receive and diffuse light emitted from the flexible display, the method being characterized by arranging a separate diffusing spacer fabric adjacent to the outer fabric so as to receive and further diffuse light emitted from the flexible display. This method offers similar advantages as obtained with the previously discussed aspect of the invention.
[0017] According to another aspect of the invention, there is provided a flexible light-emitting display adapted for use behind an outer fabric of a textile product, which flexible display has a diffusing element being arranged to receive and diffuse light emitted from the flexible display, and which textile product further comprises a separate diffusing spacer fabric arranged adjacent to the outer fabric so as to receive and further diffuse light emitted from the flexible display. This aspect offers similar advantages as obtained with the previously discussed aspects of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] These and other aspects of the present invention will now be described in more detail; with reference to the appended drawings showing currently preferred embodiments of the invention.
[0019] FIG. 1 is a front view of a textile product according to the invention,
[0020] FIG. 2 is a cross-sectional partial side view of the textile product in FIG. 1 , and
[0021] FIGS. 3-7 are cross-sectional partial side views of various embodiments of the textile product according to the invention.
DETAILED DESCRIPTION OF EMBODIMENTS
[0022] A textile product according to a basic embodiment of the present invention will now be described in relation to FIGS. 1 and 2 . The textile product 10 , here a shirt, comprises an outer fabric 12 , behind which a flexible light-emitting display 14 is arranged. The flexible display 14 comprises a flexible substrate 16 , which for example can be made of plastics or fabrics, and a plurality of discrete light sources 18 , preferably light emitting diodes (LEDs). LEDs exhibit several advantages, which become handy in this application, for example high durability, low power consumption, high luminance, etc. The flexible display 14 may emit light such that a viewer can see graphical shapes, text based characters, and etc. on the display 14 through the outer fabric 12 , and it can for example be of any type described in the above-mentioned documents WO2004/100111 and WO2006/014230.
[0023] The flexible display 14 comprises a diffusing element 20 arranged to receive and diffuse light emitted from the flexible display 14 , so as to diffuse light coming from two adjacent LEDs 18 in order to produce a substantially continuous light display. An example of such a flexible display with diffusing element is disclosed in the above-mentioned document WO2004/100111.
[0024] According to the present invention, the textile product 10 further comprises a diffusing spacer fabric 22 provided adjacent to the outer fabric 12 . Here, the diffusing spacer fabric 22 is attached to the inside of the outer fabric 12 , as can be seen in FIG. 2 , whereas the flexible display 14 in turn is attached to the diffusing spacer fabric 22 . The diffusing spacer fabric 22 is preferably laminated to the outer fabric 12 . Alternatively, it could be stitched, zipped, or hooked to the outer fabric 12 , for instance. The diffusing spacer fabric 22 acts as a second separate diffusing element, and tuning the characteristics of the two diffusing elements 20 , 22 , such as material, thickness, shape, density, etc., allows for optimization of the overall light diffusing characteristics. The diffusing spacer fabric 22 , as well as the diffusing element 20 , can for example consist of woven fabric, knitted fabric, foam, non-woven material like needle padding or fiber fill, or the like. The total thickness of the diffusing element 20 and the diffusing spacer fabric 22 should chosen in relation to the lateral distances between the light sources 18 . Optionally, the thickness of the diffusing element 20 decreases gradually towards the edges of the flexible substrate 16 , so that the contours of the flexible display 14 are less likely to be visible.
[0025] In FIG. 1 , the diffusing spacer fabric 22 has a substantially larger area compared to the flexible display 14 . Namely, the area of the diffusing spacer fabric 22 essentially matches that of the front side of the shirt 10 . The diffusing spacer fabric 22 having the substantially larger area compared to the flexible display 14 , possibly in combination with suitable strength characteristics and/or thickness of the diffusing spacer fabric 22 , prevents the contours of the flexible display 14 from being visible from the outside of garment 10 .
[0026] Optionally, the flexible display 14 may additionally comprise a flexible thermo regulating layer (not shown) provided on the opposite side of the flexible substrate 16 compared to the side with the LEDs 18 for dissipating heat from the remaining display device. The thermo regulating layer may for example be made of a non-stretchable material, preferably Neoprene. The thermo-regulating layer may further be provided with holes in a repetitive pattern for guiding heat away from the display device. Except for heat management, the thermo regulating layer also offers physical strength protection against damage to the flexible display 14 . A breathable fabric layer, such as GoreTex, may further be provided on the thermo regulating layer, for allowing heat to be transferred out from the flexible display 14 . A reflective fabric layer may further be provided between the flexible substrate 16 and the thermo-regulating layer so that any light emitted backwards from the LEDs 18 is reflected forward.
[0027] The flexible display 14 may be attached in various ways. Preferably, it is removable attached, to facilitate any repairs of the flexible display 14 , to allow it to be removed when the garment 10 is to be washed, etc. The flexible display 14 can for example be attached using velcro, snap buttons, zippers, or the like, or it can be placed in a pocket arranged inside the garment 10 . Such a pocket can for example be provided on a highly transparent display positioning fabric arranged between an inner fabric (which is part of the lining of the garment 10 ) and the diffusing spacer fabric 22 . Alternatively, the flexible display 14 (with or without any pocket or pouch) can be attached to either the diffusing spacer fabric 22 or to the inner fabric. In the latter case, the flexible display 14 is preferably also attached to diffusing spacer fabric 22 , in order to maintain the distance between the flexible display 14 and the diffusing spacer fabric 22 , so that the display performance is not altered and/or degraded. Also, a back cover having larger area than the remaining flexible display 14 can be attached to the back of the same, to facilitate attachment (for instance by stitching) of the flexible display 14 to the textile product. FIGS. 3-6 are cross-sectional partial side views illustrating various examples of how the flexible display 14 can be attached. In FIG. 3 , the flexible display 14 is attached to the diffusing spacer fabric 22 using velcro 24 , in FIG. 4 , the flexible display 14 is attached to the diffusing spacer fabric 22 by means of a pocket 26 , in FIG. 5 , the flexible display 14 is attached to an inner fabric 28 by means of a pocket 26 , which in turn is attached to the diffusing spacer fabric 22 using velcro 24 , and in FIG. 6 , the flexible display 14 is placed in a pocket 26 which is provided on a highly transparent display positioning fabric 32 arranged between the inner fabric 28 and the diffusing spacer fabric 22 . In FIG. 6 , the flexible display 14 can be accessed through an opening (not shown) in the inner fabric 28 .
[0028] Additional spacer fabric 30 may be provided around the flexible display 14 , as illustrated in FIG. 7 . That is, the additional spacer fabric 30 is placed at the same “level” as the flexible display 14 , as a lateral extension of the flexible display 14 . The thickness of the additional spacer fabric 30 preferably matches that of the flexible display 14 , so that the part of the textile product 10 incorporating the flexible display 14 gets a uniform thickness. The additional spacer fabric 30 may optionally be formed in one piece with the diffusing spacer fabric 22 .
[0029] The textile product 10 of the present invention may comprise many additional features and devices not shown in the figures. For example, it may comprise a power source for powering the display, a control unit for controlling the display, a memory for storing data related to images or animations to be displayed on the display, a communications unit for allowing wired or wireless communication with external devices, a sensor for detecting a condition and controlling the display output accordingly, audio means, etc., allowing the textile product to be used in a wide variety of applications. Also, the textile product may comprise more than one flexible display.
[0030] The person skilled in the art realizes that the present invention by no means is limited to the preferred embodiments described above. On the contrary, many modifications and variations are possible within the scope of the appended claims. For example, even though a garment is illustrated above, the textile product according to the invention may equally be a pillow, curtain, furnishing fabric, vehicle ceiling, bed textile, toy, mat or carpet, table cloth, pouch, bag, backpack, or the like.
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The present invention relates to a textile product ( 10 ) comprising an outer fabric ( 12 ) and a flexible light-emitting display ( 14 ) arranged behind the outer fabric, which flexible display has a diffusing element ( 20 ) being arranged to receive and diffuse light emitted from the flexible display. The textile product is characterized by a diffusing spacer fabric ( 20 ) arranged adjacent to the outer fabric so as to receive and further diffuse light emitted from the flexible display, which diffusing spacer fabric ( 22 ) is separate from the diffusing element ( 20 ). The diffusing spacer fabric acts as a second diffusing element, and allows for improved diffusing functionality. The present invention also relates to a method for the manufacturing of such a textile product, and a flexible light-emitting display adapted for use in a textile product.
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BACKGROUND
[0001] The invention is related to a reflective display apparatus, especially to a method and an apparatus for manufacturing an electrophoretic display.
[0002] An electrophoretic display (EPD) is a reflective display apparatus based on utilizing electrophoretic effect of electriferous particles dispersed in a dielectric solvent. Currently, an electrophoretic display includes a glass substrate, a transparent protection layer opposite to the glass substrate with an interval, and an electrophoretic layer sandwiched between the glass substrate and the transparent protection layer. The electrophoretic display is divided into a passive matrix drive type and an active matrix drive type by driving means. For a passive matrix drive type electrophoretic display, it is necessary to dispose row electrodes and transparent column electrodes on the glass substrate and transparent protection layer. Correspondingly, for an active matrix drive type electrophoretic display, a TFT matrix and a pixel electrode and a transparent plate electrode without pattern are needed to be disposed on the glass substrate and the transparent protection layer, respectively.
[0003] Along with a widely used of the electrophoretic display and mostly used on portable devices, it becomes more important to design light-weight and thin-thickness electrophoretic displays. At the present time, a soft electrophoretic display using a flexible plate to replace the glass substrate is respected to be an apparatus which can own all virtues described above and became primary products of the market in future. However, how to improve the manufacturing yield rate and keep preferable reliability as much should be solved desirously.
BRIEF SUMMARY
[0004] The present invention is directed to provide a method of manufacturing electrophoretic display which can increase the manufacturing quality and improve the electrophoretic display reliablity to achieve product commerce.
[0005] The present invention is directed to provide an apparatus for manufacturing electrophoretic display which can increase the manufacturing quality and improve the electrophoretic display reliability to achieve product commerce.
[0006] According to an embodiment of the present invention, a method of manufacturing an electrophoretic display is provided. The method includes steps of:
[0007] providing a substrate;
[0008] providing a flexible plate disposed on the substrate;
[0009] providing an electrophoretic layer disposed on the flexible plate;
[0010] providing a transparent protection layer disposed on the electrophoretic layer;
[0011] providing an edge protection member disposed between the flexible plate and the transparent protection layer to surround the electrophoretic layer; and
[0012] providing a laser to irradiate the flexible plate from a side of the substrate without the flexible plate being disposed, so as to separate the substrate from the flexible plate.
[0013] According to another embodiment of the present invention, an apparatus of manufacturing an electrophoretic display is provided, which is used to separate a substrate from an electrophoretic display, the electrophoretic display including:
[0014] a flexible plate disposed on a substrate;
[0015] an electrophoretic layer disposed on the flexible plate;
[0016] a transparent protection layer disposed on the electrophoretic layer; and
[0017] an edge protection member disposed between the flexible plate and the transparent protection layer to surround the electrophoretic layer,
[0018] an apparatus of manufacturing the electrophoretic display, which is used to separate the substrate from the electrophoretic display, the manufacturing apparatus comprising:
[0019] a transmission device for transmitting the electrophoretic display;
[0020] an adsorption device for fixing the electrophoretic display with the substrate transmitted by the transmission device by means of adsorption;
[0021] a laser device for generating a laser to irradiate the flexible plate from a side of the substrate without the flexible plate being disposed, so as to separate the substrate from the electrophoretic display; and
[0022] a positioning system for detecting a position of the electrophoretic display in order to adjust the laser device.
[0023] The apparatus of manufacturing an electrophoretic display further includes:
[0024] a storage device used to store the electrophoretic display; and
[0025] a recycling device used to store the substrate separated from the electrophoretic display.
[0026] According to the embodiments of the invention, separating substrate and flexible plate by laser would not damage the flexible plate and also increase the manufacturing quality of the electrophoretic display. Moreover, the electrophoretic layer can be protected by the edge protection member surrounding the electrophoretic layer and improve the electrophoretic display reliablity to achieve product commerce.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] These and other features and advantages of the various embodiments disclosed herein will be better understood with respect to the following description and drawings, in which like numbers refer to like parts throughout, and in which:
[0028] FIG. 1 is a cross sectional, schematic view of a substrate according to an embodiment of present invention.
[0029] FIG. 2 is a cross sectional, schematic view of a flexible plate on the substrate of FIG. 1 .
[0030] FIG. 3 is a cross sectional, schematic view of an electrophoretic layer on the flexible plate of FIG. 2 .
[0031] FIG. 4 is a cross sectional, schematic view of a transparent protection layer on the electrophoretic layer of FIG. 3 .
[0032] FIG. 5 is a cross sectional, schematic view of an edge protection member disposed between the transparent protection layer and the flexible plate of FIG. 4 .
[0033] FIG. 6 is a cross sectional, schematic view of a driving IC on the flexible plate and an edge protection member covering the driving IC of FIG. 5 .
[0034] FIG. 7 is a schematic view of a laser to irradiate the flexible plate from a side of the substrate without the flexible plate being disposed of FIG. 6 .
[0035] FIG. 8 is a cross sectional, schematic view of an electrophoretic display separated from the substrate of FIG. 7 .
[0036] FIG. 9 is a cross sectional, schematic view of an apparatus for manufacturing an electrophoretic display according to an embodiment of present invention.
DETAILED DESCRIPTION
[0037] Referring to FIG. 1 and FIG. 8 , a method for manufacturing an electrophoretic display 100 is provided according to an embodiment of the invention. The method includes steps as follows.
[0038] As shown in FIG. 1 , a substrate 200 is provided, which can be a glass substrate, metal substrate, steel substrate or other rigid material substrates.
[0039] As shown in FIG. 2 , a flexible plate 110 is disposed on the substrate 200 . The material of the flexible plate 110 can be plastic, preferably to be polyimide (PI), polyethylene terephthalate (PET), polyethersulfone (PES), or polycarbonate (PC). The flexible plate 110 is convenient to be separated from the glass substrate 200 by radiated using invisible laser, such as UV laser whose wavelength is in a range of 300 nm to 400 nm. The required circuits and a first driving electrode (not shown in FIG. 2 ) are disposed on the flexible plate 110 .
[0040] As shown in FIG. 3 , an electrophoretic layer 120 is disposed on the flexible plate 110 . The electrophoretic layer 120 includes a dielectric solvent and electriferous particles dispersed in the dielectric solvent.
[0041] As shown in FIG. 4 , a transparent protection layer 130 is disposed on the electrophoretic layer 120 . The material of the transparent protection layer 130 can be transparent plastic. A second driving electrode (not shown in FIG. 4 ) is disposed on the electrophoretic layer 120 adjacent to the transparent protection layer 130 (between the transparent protection layer 130 and the electrophoretic layer 120 ). The second driving electrode is a transparent electrode, such as an Indium Tin Oxide (ITO) electrode, and matches with the first driving electrode on the flexible plate 110 . Illuminated in detail, when a passive matrix drive type electrophoretic display 100 is manufactured, the first driving electrode on the flexible plate 110 and the second driving electrode on the transparent protection layer 130 are row electrode and transparent column electrode respectively. On the contrary, to an active matrix drive type electrophoretic display 100 , the first driving electrode on the flexible plate 110 and the second driving electrode on the transparent protection layer 130 are pixel electrode and transparent plate electrode without pattern, respectively, and an active device matrix, such as a thin film transistor (TFT) matrix, is arranged on the flexible plate 110 to electrically connect to the pixel electrode.
[0042] As shown in FIG. 5 , an edge protection member 140 is disposed between the flexible plate 110 and the transparent protection layer 130 to surround the electrophoretic layer 120 . The material of the edge protection member 140 can be resin material, such as Phenoxy Resin.
[0043] As shown in FIG. 6 , a driving integrated circuit (IC) 150 and an edge reinforcement member 160 are provided. The driving IC 150 in juxtaposition with the electrophoretic layer 120 are disposed on the flexible plate 110 and connect electrically to the circuits and the first driving electrode on the flexible plate 110 . The driving IC 150 can be a chip on glass (COG) module. The edge reinforcement member 160 covers the driving IC 150 and connects to the transparent protection layer 130 to protect the driving IC 150 . The material of the edge reinforcement member 160 can be plastic material, such as UV polymeric gel, silica gel, or polyurethane (PU). Of course, the driving IC 150 is not limited to be disposed on the flexible plate 110 , and also can be a driving control module (not shown in FIG. 6 ) independent to the electrophoretic display 100 .
[0044] As shown in FIG. 7 , a laser 170 is provided to irradiate the flexible plate 110 from a side of the substrate 200 without the flexible plate 110 being disposed, so as to separate the substrate 200 from the flexible plate 110 . A wavelength of the laser 170 is in a range of 300 nm to 400 nm and a pulse energy is in a range of 250 to 700 mJ. The energy provided by the laser 170 can break the juncture between the flexible plate 110 and the substrate 200 and separate the substrate 200 .
[0045] FIG. 7 shows a cross sectional, schematic view of the electrophoretic display 100 separated from the substrate 200 by laser.
[0046] As shown in FIG. 9 , an apparatus 10 for manufacturing the electrophoretic display 100 is provided according to another embodiment. The apparatus 10 includes a mechanical arm 11 , an adsorption device 12 , a laser device 13 , a positioning system 14 , a storage device 15 and a recycling device 16 .
[0047] The mechanical arm 11 transmits the electrophoretic display and the substrate 200 separated of FIG. 6 and the electrophoretic display 100 of FIG. 8 . But it is not limit to the mechanical arm 11 , and all other transmission devices which can transmit electrophoretic display can be available. The mechanical arm 11 can be driven by a cylinder motor and capable of being rotated by 90 degree.
[0048] Using means of vacuum adsorption, the adsorption device 12 can fix the electrophoretic display with the substrate 200 transmitted by the mechanical arm 11 of FIG. 6 . But it is not limit to the adsorption device 12 , and all other adsorption devices can be available.
[0049] The laser device 13 can generate a laser 170 to irradiate the flexible plate 110 with the substrate 200 from a side of the substrate 200 without the flexible plate 110 fixed by the adsorption device 12 in FIG. 7 , so as to separate the substrate 200 from the electrophoretic display. A wavelength of the laser 170 from the laser device 13 can be in a range of 300 nm to 400 nm and a pulse energy of the laser 170 is in a range of 250 to 700 mJ.
[0050] The positioning system 14 is used to detect the position of the flexible plate 110 with the substrate 200 transmitted by the laser device 13 and mechanical arm 11 of FIG. 6 in order to adjust the position. The positioning system 14 can be a charge coupled device (CCD) positioning system.
[0051] The storage device 15 is used to store the electrophoretic display with the substrate 200 of FIG. 6 and the electrophoretic display 100 separated of FIG. 8 .
[0052] The recycling device 16 which can be a substrate placement device is used to store the substrate 200 separated.
[0053] As described above, according to the embodiments of the invention, separating substrate and flexible plate by laser would not damage the flexible plate and also increase the manufacturing quality of the electrophoretic display. Moreover, the electrophoretic layer can be protected by the edge protection member surrounding the electrophoretic layer and improve the electrophoretic display reliablity to achieve product commerce.
[0054] Of course, the material of the substrate 200 , flexible plate 110 , edge protection member 140 and the wavelength or the pulse energy of laser can be changed according to the invention.
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A method for manufacturing an electrophoretic display includes the steps of: providing a substrate; forming a flexible plate on the substrate; forming an electrophoretic layer on the flexible plate; forming a transparent protection layer on the electrophoretic layer; forming an edge protection member between the flexible plate and the transparent protection member, the edge protection member surrounding the electrophoretic layer; and providing a laser beam to irradiate the flexible plate from a side of the substrate facing away from flexible plate, so as to release the substrate from the flexible plate.
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CROSS REFERENCES TO RELATED APPLICATIONS
[0001] The present application claims priority to U.S. Provisional patent application No. 61/244053, filed Sep. 20, 2009, and U.S. Provisional patent No. 61/305146, filed on Feb. 17, 2010, both of which are hereby incorporated by reference in their entireties.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] Not Applicable
BACKGROUND OF THE INVENTION
[0003] 1. Field of the Invention
[0004] The present invention is related to wireless tracking systems and methods utilizing near-field communication devices. More specifically, the present invention relates to a system and method utilizing near-field communication devices for analyzing near-field communication interactions.
[0005] 2. Description of the Related Art
[0006] Real-time knowledge of resources, whether the resources are assets or people, is becoming a necessary tool of many businesses. Real-time knowledge of the location, status and movement of crucial resources can allow a business to operate more efficiently and with fewer errors. However, many businesses employ hundreds if not thousands of resources in a single facility, and these resources need to be accounted for by a central system that is user friendly.
[0007] For example, in a typical hospital there are numerous shifts of employees that utilize the same equipment. When a new shift arrives, the ability to quickly locate medical equipment not only results in a more efficient use of resources, but also can result in averting a medical emergency. Thus, the tracking of medical equipment in a hospital is becoming a standard practice.
[0008] The tracking of objects in other facilities is rapidly becoming a means of achieving greater efficiency. A typical radio frequency identification system includes at least multiple tagged objects, each of which transmits a signal, multiple receivers for receiving the transmissions from the tagged objects, and a processing means for analyzing the transmissions to determine the locations of the tagged objects within a predetermined environment.
[0009] The prior art discloses various tracking systems and uses of near-field communication devices. Near field communication typically operates in the 13.56 MHz frequency range, over a distance of one meter or less and usually a few centimeters. Near field communication technology is standardized in ISO 18092, ECMA 340, and ETSI TS 102 190.
[0010] One reference discloses an adapter for a tag that is configured to emulate a near filed communication reader-to-reader tag.
[0011] Another reference discloses a medical diagnostic system that includes a data acquisition device having a near field communication device for transfer of data.
[0012] Another reference discloses using ECMA 340 standard for near field communication.
[0013] Another reference discloses a system for monitoring a patient that uses a personal status monitoring device, such as an ECG electrode assembly, which transmits a signal to an intermediary device, such as a PDA, which transmits to a server using a WLAN.
[0014] Another reference discloses an object identifier that transmits both an IR signal and a RF signal for location determination.
[0015] Another reference discloses a system which allows for a location to be determined without requiring precise calculations through use of an object identifier that transmits one identifier corresponding to an object identifier and a second identifier which is a group identifier.
[0016] Another reference discloses a system for recording object associations based on signals for object identifiers.
[0017] Another reference discloses a system that uses NFC technology to determine a secondary transport mechanism.
[0018] Another reference discloses a system that uses BLUETOOTH technology integrated in a cellular telephone to provide interpersonal communications between individuals.
[0019] Another reference discloses near field communication devices that determine an efficient protocol for sharing information.
[0020] Another reference discloses passing advertising messages to a mobile client using near field communication technology.
[0021] As stated above, the problem is inadequate resource visibility in a business. Businesses such as hospitals, need to locate resources (assets and people), know the status of the resources, and understand the usage history of the resources to enable business improvement.
[0022] Specific problems for hospitals include tracking infections in a hospital to determine a source and other areas or individuals that may be infected. Other problems include spotting emerging patterns of infection and outbreaks to mitigate those affected. Further, for MEDICARE and other insurance providers, hospitals and other medical facilities need to demonstrate that patients received their required care in order to receive payment for such care. The prior art has failed to provide an adequate solution to these problems.
[0023] Further, there is a need in the health care market to determine when interactions occur between patient worn devices and clinician worn devices. Being able to detect this interaction will drive many applications that revolve around workflow, patient flow and asset tracking. To enable the detection of these interaction events, a communication protocol must be defined such that the tags will recognize when they are in-range of each other and report on the in-range event. Off-the-shelf technologies can be employed for this use case but the battery-life, communication range and data rate requirements are often traded for communication performance. For example, peer-to-peer WiFi could be used to establish a near-real time connection between two devices but the battery life of the WiFi-enabled device would be on the order of 1-2 days which would not support the application need. Many other technologies have the same drawbacks.
[0024] To accomplish these applications, one must find a system that doesn't trade battery life for response time, or communication distance for battery life.
BRIEF SUMMARY OF THE INVENTION
[0025] The present invention provides a solution in the form of a low-power interaction detection circuit that triggers a higher-power communication system that can transfer more meaningful data after an interaction event has been detected. The solution determines a near-field communication interaction between objects through wireless tracking The present invention utilizes near-field communication devices attached to objects (including individuals) and the objects also have the capability to transmit signals for reception by sensors stationed throughout a facility which forward the signals to an information engine for analysis of a near-field communication interaction.
[0026] One aspect of the present invention is a system for monitoring interaction data for multiple users and objects utilizing near-field communication devices in an indoor facility through a medium range wireless communication format and a short range wireless communication format. The system includes a mesh network, a plurality of near-field communication devices and an information engine. Each of the plurality of near-field communication devices transmits a beacon signal using a short range wireless communication format receivable by another near-field communication device when the near-field communication devices are within physical proximity of each other. At least one of the near-field communication devices transmits interaction data using a medium range wireless communication format to the mesh network. The information engine is in communication with the mesh network and processes the interaction data.
[0027] The medium range wireless communication format is preferably selected from ZIGBEE communication format, Bluetooth communication format, Low-Power BlueTooth communication format, WiFi communication format, Low-Power WiFi communication format, Ultra Wide Band communication format, Ultrasound communication format or Infrared communication format. The short range wireless communication format is preferably selected from a near-field communication format, a low frequency communication format or a magnetic field communication format. Alternatively, the short range wireless communication format is selected from a magnetic induction communication format, 9 kHz communication format, <125 kHz communication format, 125 kHz RFID communication format, 13.56 MHz communication format, 433 MHz communication format, 433 MHz RFID communication format, or 900 MHz RFID communication format.
[0028] Another aspect of the present invention is a system for determining a business relationship between individuals within a facility. The system includes multiple near-field communication devices, multiple tags, a mesh network and an information engine. The mesh network is preferably an 802.15.4 ZIGBEE wireless sensor network. Each of the first near-field communication devices represented is associated with an individual. Each of the tags represents an object. The mesh network includes multiple plug-in sensors located within the facility. The information engine is in communication with the mesh network. The information engine determines a business relationship between a first bearer and a second bearer having a near-field communication interaction based on at least two of multiple factors which include a position location of the interaction, a duration of the interaction, a previous location of the first bearer, a previous location of the second bearer and the number of other objects located near the near-field communication interaction.
[0029] In a preferred embodiment, the plurality of factors further includes a position designation of the first person and a position designation of the second person and a number of previous interactions between the first person and the second person within a predetermined time period.
[0030] Another aspect of the present invention is a method for determining a business relationship between individuals within a facility. The method includes transmitting a signal from a tag associated with a first person, and the signal comprises data about a near-field communication interaction between the first person and a second person. The method also includes receiving the signal from the first tag at a mesh network established within the facility. The method also includes determining that an interaction is occurring between the first person and the second person. The method also includes determining a business relationship between the first person and the second person based on multiple factors. The multiple factors can include a position location of the interaction, a duration of the interaction, a previous location of the first person prior to the interaction, a previous location of the second person prior to the interaction, a position designation of the first person and a position designation of the second person, a number of previous interactions between the first person and the second person within a predetermined time period, and the number of other persons at the interaction.
[0031] Yet another aspect of the present invention is a system for determining a business relationship between individuals within a facility. The system includes multiple near-field communication devices, multiple tags, a mesh network and an information engine. Each of the near-field communication devices is associated with an individual person. Each of the tags represents a first object. The mesh network includes multiple plug-in sensors located within the facility. The information engine is in communication with the mesh network. The information engine analyzes a near-field communication interaction. The multiple factors for the near field communication interaction include a position location of the interaction, a duration of the interaction, a previous location of the first person prior to the interaction, and information for a mobile object within a predetermined distance of the location of the interaction.
[0032] In one example, the information engine analyzes the near-field communication interaction to determine a billing charge for services of the first person. In another example, the facility is a hospital and the information engine analyzes the near-field communication interaction to determine medical services provided to a patient.
[0033] Yet another aspect of the present invention is a system for analyzing an action of an individual. The system includes near-field communication devices, tags, a mesh network and an information engine. Each of the near-field communication devices is associated with an individual person. Each of the tags is associated with a mobile object. The mesh network includes multiple sensors positioned within a facility. The mesh network receives transmissions from each tags and each of the near-field communication devices. The information engine is in communication with the mesh network. The information engine analyzes near-field communication interactions between individuals. The information engine further analyzes an action of a first person based on a plurality of factors including a position location of the action, a duration of the action, a previous location of the first person prior to the action, and information for a mobile object within a predetermined distance of the location of the action.
[0034] Each communication device preferably has a low-power, short-range (<1 foot) communication feature that can detect the presence, or absence, of a signal from another device. Short bits of information are preferably exchanged (<256 bits) between devices but such an exchange is not mandatory. RFID systems operating at frequencies of sub-125 kHz, 125 kHz, 433 MHz, 900 MHz, or 2.4 GHz are used with the present invention. The communication devices alternatively transmit at frequencies as low as 5 kiloHertz (“kHz”) and as high as 900 MegaHertz (“MHz”). Other frequencies utilized by the tags for a low-power short-range communication system include 9 kHz, <125 kHz, 433 MHz, and 900 MHz.
[0035] Each device preferably contains a low-power, medium-range (1 foot to 30 feet) wireless communication system. Such wireless communication systems include ZIGBEE, BLUETOOTH, Low-Power BLUETOOTH, WiFi or Low-Power WiFi, Ultra Wide Band (“UWB”), Ultrasound and Infrared communication systems. The wireless communication system is used to exchange device specific information after the low-power short-range system has indicated that an interaction has occurred. Those skilled in the pertinent art will recognize that the wireless communication system can also be used independent of the low-power short-range system for other wireless communication applications such as location and tracking, sense and control, building automation, smart energy, telecom applications, consumer building automation, remote control applications, home health care, personal fitness, personal wellness, and many other applications.
[0036] Each communication device preferably continuously transmits a beacon signal using the short-range communication protocol. When a beacon signal is received by another communication device, the receiving communication device can respond using the low-power communication circuit and/or it can respond using the medium-power protocol. The medium-power communication system can transfer larger data packets at a higher transmission rate. Data that might be included in a medium-power transmission include device ID, time stamp, location information, user information, software version, and/or protocol version. A medium-power transmission is preferably acknowledged when received by the receiving communication device. Further, at this point either communication device, or both communication devices, can transmit the information from the interaction to the medium-power infrastructure or to a neighboring communication device. Additionally, the communication devices may also elect to store the interaction information and download/transmit the interaction information at a later time.
[0037] Having briefly described the present invention, the above and further objects, features and advantages thereof will be recognized by those skilled in the pertinent art from the following detailed description of the invention when taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0038] FIG. 1 is schematic view of a system for analyzing a near-field communication interaction.
[0039] FIG. 2 is a multi-floor view of a facility employing a system for analyzing a near-field communication interaction.
[0040] FIG. 3 is a floor plan view of a single floor in a facility employing the system for analyzing a near-field communication interaction.
[0041] FIG. 4 is a block diagram of a flow of information utilizing a system for analyzing a near-field communication interaction.
[0042] FIG. 5 is a block diagram of a flow of information utilizing a system for analyzing a near-field communication interaction.
[0043] FIG. 5A is an illustration of a valid near-field link between near-field communication devices.
[0044] FIG. 5B is an illustration of a valid near-field link between near-field communication devices.
[0045] FIG. 5C is an illustration of a valid near-field link between near-field communication devices.
[0046] FIG. 6 is an illustration of a failed near-field link between near-field communication devices due to a distance between near-field communication devices.
[0047] FIG. 6A is an illustration of a failed near-field link between near-field communication devices due to a distance between near-field communication devices.
[0048] FIG. 6B is an illustration of a failed near-field link between near-field communication devices due to a distance between near-field communication devices.
[0049] FIG. 7 is a flow chart of a method for analyzing a near-field communication interaction.
[0050] FIG. 8 is a plan view of an identification badge containing a communication device.
DETAILED DESCRIPTION OF THE INVENTION
[0051] As shown in FIGS. 1-3 , a system for tracking objects within a facility is generally designated 50 . The system 50 is capable of analyzing an interaction between objects, individuals 58 and/or objects 100 . The system 50 preferably includes a plurality of sensors 55 , a plurality of bridges 56 , a plurality of near-field communication devices 59 , a plurality of tags 60 , and at least one information engine 65 . The sensors 55 form a mesh network for receiving signals from the near-field communication devices 59 and tags 60 . One example of the components of the system 50 is disclosed in U.S. Pat. No. 7,197,326, for a Wireless Position Location And Tracking System, which is hereby incorporated by reference in its entirety. A more specific example of the sensors 55 is disclosed in U.S. Pat. No. 7,324,824, for a Plug-In Network Appliance, which is hereby incorporated by reference in its entirety.
[0052] The system 50 is preferably employed at a facility 70 such as a business office, factory, home, hospital and/or government agency building. The system 50 is preferably utilized to track and locate various objects (including persons) positioned throughout the facility 70 in order to analyze near-field communication interactions. The near-field communication devices 59 and tags 60 preferably continuously transmit signals on a predetermined time cycle, and these signals are received by sensors 55 positioned throughout the facility 70 . Alternatively, the tags 60 and near-field communication devices 59 transmit signals in a random, ad-hoc or dynamic manner, and these signals are received by the sensors 55 positioned throughout the facility 70 . The sensors 55 transmit the data from the near-field communication devices 59 and tags 60 to a bridge 56 for transmission to the information engine 65 . If a sensor 55 is unable to transmit to a bridge 56 , the sensor 55 may transmit to another sensor 55 in a mesh network for eventual transmission to a bridge 56 . In a preferred embodiment, a transmission may be sent from a transmission distance of six sensors 55 from a bridge 56 . Alternatively, a transmission is sent from a transmission distance ranging from ten to twenty sensors 55 from a bridge 56 . The information engine 65 preferably continuously receives transmissions from the mesh network formed by the sensors 55 via the bridges 56 concerning the movement of persons 58 bearing a near-field communication device 59 and/or devices 100 bearing a tag 60 within the facility 70 . The information engine 65 processes the transmissions from the sensors 55 and calculates a real-time position for each of the objects, persons 58 bearing a near-field communication device 59 or objects 100 bearing a tag 60 , within the facility 70 . The real-time location information for each of the objects is preferably displayed on an image of a floor plan of the facility 70 , or if the facility 70 has multiple floors, then on the floor plan images of the floors of the facility 70 . The floor plan image may be used with a graphical user interface of a computer, personal digital assistant, or the like so that an individual of the facility 70 is able to quickly locate objects 100 within the facility 70 .
[0053] As shown in FIG. 1 , the system 50 utilizes sensors 55 to monitor and identify the real-time position of individuals bearing or integrated with communication devices 59 . The sensors 55 a - f preferably wirelessly communicate with each other (shown as double arrow lines) and with an information engine 65 through a wired connection 66 via at least one bridge 56 , such as disclosed in the above-mentioned U.S. Pat. No. 7,324,824 for a Plug-In Network Appliance. The near-field communication devices 59 and tags 60 preferably transmit wireless signals 57 which are received by the sensors 55 a - e, which then transmit signals to bridges 56 for eventual transmission to the information engine 65 . The information engine 65 is preferably located on-site at the facility 70 . However, the system 50 may also include an off-site information engine 65 , not shown.
[0054] In a preferred embodiment, the near-field communication device 59 preferably operates at a short range communication format of magnetic induction, 9 kHz, <125 kHz, 125 kHz RFID, 13.56 MHz, 433 MHz, 433 MHz RFID, and 900 MHz RFID, and preferably at a bit rate of less 256 kilobits per second or approximately 426 kilobits per second. The communication format is preferably IEEE Standard 802.15.4. Further, the near-field communication device 59 also operates using a medium range communication format. The medium range communication format can include ZIGBEE, BLUETOOTH, BLUETOOTH low energy, WiFi, Low-power WiFi, Ultrasound and Infrared communication formats. Those skilled in the pertinent art will recognize that other communication formats may be used with departing from the scope and spirit of the present invention. The medium range communication format also allows the near-field communication device 59 to communicate with the sensors 55 to transmit interaction information.
[0055] In a preferred embodiment, the tag 60 preferably transmits a radio frequency signal of approximately 2.48 GigaHertz (“GHz”). The tags 60 may be constructed with an asset theft protection system such as disclosed in Baranowski et al., U.S. Pat. No. 7,443,297 for a Wireless Tracking System And Method With Optical Tag Removal Detection, which is hereby incorporated by reference in its entirety. The tags 60 and near-field communication devices 59 may be designed to avoid multipath errors such as disclosed in Nierenberg et al., U.S. Pat. No. 7,504,928 for a Wireless Tracking System And Method Utilizing Tags With Variable Power Level Transmissions, and Caliri et al., U.S. Patent Publication Number 2008/0012767 for a Wireless Tracking System And Method With Multipath Error Mitigation, both of which are hereby incorporated by reference in their entireties.
[0056] As shown in FIGS. 2-3 , the facility 70 is depicted as a hospital. The facility 70 has multiple floors 75 a - c. Each floor 75 a, 75 b and 75 c has multiple rooms 90 a - i, with each room 90 accessible through a door 85 . Positioned throughout the facility 70 are sensors 55 a - o for obtaining readings from communication devices 59 and tags 60 attached to people or objects. A bridge 56 is also shown for receiving transmissions from the sensors 55 for forwarding to the information engine 65 . For example, as shown in FIG. 2 , the system 50 determines that individuals 58 a, 58 b and 58 c are located in a surgery room and are using device 100 c, which is a surgical kit. The information engine 65 analyzes the interaction by monitoring the duration of the interaction, the devices 100 utilized, the location of the interaction (surgery), the previous location of the individuals 58 (possibly a surgical prep room) and additional factors.
[0057] In another example, as shown in FIG. 3 , individuals 58 a, 58 b and 58 c are located in a patient's room and are using a medical object with an attached tag 60 c, which is a patient monitoring unit. In this example, individual 58 a is a patient, individual 58 b is a physician, and individual 58 c is a nurse. The near-field communication device 59 of each individual 58 a, 58 b and 58 c communicates with the other near-field communication devices 59 using a short range communication format as discussed above. In such a situation, each near-field communication device 59 registers the short range beacons transmitted by other near-field communication devices 59 . Additionally, interaction information may be transferred between the near-field communication devices 59 using a medium range communication format as discussed above. Further, one, two or all of the near-field communication devices 59 transfer interaction information to at least one sensor 55 using a medium range communication format. The sensor 55 then transmits the interaction information to an information engine 65 , preferably using a mesh network. The information engine 65 analyzes the near-field communication interaction information received by the sensor 55 by monitoring the duration of the near-field communication interaction, the objects 100 utilized, the location of the near-field communication interaction (patient's room), the previous location of the individuals 58 and additional factors. The information engine 65 preferably uses this data to generate billing information for the patient.
[0058] FIG. 4 illustrates a preferred architecture of the system 50 . For description purposes, the information providers are set forth on one side of the network and the operations is set forth on the other side of the network. However, those skilled in the pertinent art will recognize that the illustrated architecture of the system 50 is not meant to limit any physical relationship between information providers and operations. In fact, an individual 58 could be tracked while accessing information from an object 100 such as a computer 66 in operations. The information providers include individuals 58 that wear near-field communication devices 59 , equipment 100 a bearing tags 60 , sterilizable equipment 100 b bearing sterilizable tags 60 , and the like. A description of sterilizable tags 60 and system is found in Caliri et al., U.S. Pat. No. 7,636,046 for Wireless Tracking System And Method With Extreme Temperature Resistant Tag, which is hereby incorporated by reference in its entirety. Another description of a sterilizable tag 60 and system is found in Perkins et al., U.S. Pat. No. 7,701,334 for Wireless Tracking System And Method For Sterilizable Object, which is hereby incorporated by reference in its entirety. A bridge 56 acts as an intermediary between the information providers and operations. The bridge 56 communicates information to the information engine 65 which analyzes the information to determine an interaction information between individuals for access through an enterprise local area network for display on computers 66 or other graphical user interface devices.
[0059] A block diagram of a system utilizing near-field communication is illustrated in FIG. 5 . In FIG. 5 , two individuals 58 a and 58 b are in proximity in order to “mash-up” and have a valid near-field communication interaction with each individual's near-field communication devices 59 a and 59 b using a short range communication format as discussed above. A signal is transmitted from one of the individuals 58 a near communication device 59 a to a sensor 55 of a mesh network utilizing a medium range communication format as discussed above. The signal contains information pertaining to the near-field communication interaction. The sensor 55 transmits the signal through the mesh network to a bridge 56 for further transmission to an information processing engine 65 .
[0060] FIGS. 5A , 5 B and 5 C illustrate a valid near field communication link which occurs when the two near-field communication devices 59 a and 59 b are within a predetermined distance of each other (d<d isolated). Preferably the distance is one meter or less, and most preferably the distance is ten centimeters or less. Most preferably there is a physical touch between the two near field communication devices. Requiring such proximity allows for power savings since the transmission field for each of the near field communication devices 59 a and 59 b is a minimal amount. If the near field communication device 59 were to transmit using a typical RFID signal or BLUETOOTH signal, then the power consumption would be greater. Thos skilled in the art will recognize that the tag 60 and near field communication device 59 may be the same physical device with circuitry for both applications.
[0061] FIGS. 6 , 6 A and 6 B illustrate an unsuccessful near-filed communication link. In this situation, the two near-field communication devices 59 a and 59 b are not within a predetermined distance of each other (d>d isolated). Preferably, the distance is more than one meter and most preferably the distance is more than ten centimeters. In such a situation, there is no near field communication interaction. Thus, even though the near-field communication devices 59 a and 59 b are transmitting signal beacons, the individuals 58 a and 58 b are too far apart to detect a beacon signal from the other near-field communication device 59 .
[0062] A method 300 utilizing near field communication is shown in FIG. 7 . At block 302 , a sensor 55 senses for a near field communication interaction (“mash-up”) between at least two near-field communication devices 59 . At a decision block 303 , if no near field communication interaction is detected, then the sensor 55 continues to search for a near field communication interaction at block 302 . However, if a near field communication interaction is detected by the sensor 55 at decision block 303 , the near field communication interaction is recorded at block 304 . Next, at block 305 , data for the near field communication interaction is transmitted over the mesh network.
[0063] The near-field communication device 59 preferably includes a microcontroller, a first transceiver for transmitting at the short range communication format, a second transceiver for transmitting at the medium range communication format, a memory, and a power supply. The transmissions are transmitted through the transceivers. The power supply provides power to the components of the near-field communication device 59 . All of the components are preferably contained within a housing. A tag 60 preferably has the same components and structure of the near-field communication device 59 except the tag 60 preferably only operates using the medium range communication format.
[0064] As shown in FIG. 8 , an identification badge 141 is preferably utilized as a support for a near-field communication device 59 for a person 58 . Alternatively, the identification badge 141 is the near-field communication device 59 .
[0065] In one embodiment, the near-field communication interaction is utilized to authenticate a bearer of a near-field communication device 59 for access to at least one of or a combination of a computer, medical equipment, a protected area of the facility, a medication drawer, or a patient's room. For example, an individual 58 bearing the near-field communication device 59 is a physician and the physician 58 is granted access to a patient's room through a near-field communication interaction with a near-field communication device 59 on a door of the patient's room. In one example, the patient has a highly contagious disease and the tracking of access to the patient's room allows a hospital to know who has been exposed to the patient.
[0066] In another embodiment, the near-field communication interaction is utilized to track proper hand washing at a hospital. In this example, a near-field device 59 is positioned near a hand washing station for sterilizing hospital personal prior to surgery or similar procedures that require sterilization. When a bearer of a near field device 59 sterilizes his/her hands at the station, the interaction of the near-field devices 59 is recorded and transmitted to a sensor 55 for recordation at an information engine 65 . In this manner, the hospital has a record to demonstrate that proper sterilization was performed prior to surgery or similar procedure requiring sterilization.
[0067] From the foregoing it is believed that those skilled in the pertinent art will recognize the meritorious advancement of this invention and will readily understand that while the present invention has been described in association with a preferred embodiment thereof, and other embodiments illustrated in the accompanying drawings, numerous changes modification and substitutions of equivalents may be made therein without departing from the spirit and scope of this invention which is intended to be unlimited by the foregoing except as may appear in the following appended claim. Therefore, the embodiments of the invention in which an exclusive property or privilege is claimed are defined in the following appended claims.
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The present invention provides a method and system for determining a near-field communication interaction in a wireless tracking mesh network. The present invention preferably utilizes near-field communication devices in conjunction with tracking tags to transmit signals for reception by sensors stationed throughout a facility which form a mesh network and forward the signals to an information engine for analysis. Bearers of the near-field communication devices preferably include individuals, objects, assets and rooms of the facility.
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FIELD OF THE INVENTION
This invention relates to a method of improving the washing ability of wash water in a washing machine, as well as apparatus for carrying out the method.
BACKGROUND OF THE INVENTION
It is known that the presence of a ceramic material in water enhances the washing ability of the water and reduces or dispenses with the need for a detergent in the water. During the wash and rinse cycles, agitation of the wash load results in friction between the water and the ceramic. As a result, a surplus of hydroxyl ions are formed which reduces the surface tension of the water. The cleaning ability of the water is thereby enhanced.
There have been several applications of this principle in which a ceramic material or other water activating material, such as tourmaline, is provided inside a washing machine.
There is, for example, U.S. Pat. No. 5,309,739, which describes a clothes washing machine having a tourmaline ceramic coating on the bottom surface of the wash basket for reacting with the wash water to form hydroxyl ions which reduce the surface tension of the water. An ultrasonic vibrator is mounted on the wash basket across from the coating to generate waves in the wash water to accelerate the reaction between the coating and the wash water. Alternatively, the coating is applied to the agitator in the wash basket.
Another application is described in U.S. Pat. No. 5,421,174 in which a container with ceramic material is provided on the agitator in the wash basket of the washing machine. The container is provided with a plurality of holes for contact of the ceramic with the wash water.
In both the above applications, the washing machine is specially adapted for its specific purpose during the manufacturing stage and no provision is made for the application of the principle to a conventional washing machine.
In another application, as described in U.S. Pat. No. 5,211,689, the ceramic material is located inside a disc which is provided with an annular float. The ceramic material is in the form of spherical beads and the disc is provided with openings for contact between the wash water and the beads. In use, one or more of the discs are added to the wash load and they circulate through it during the wash cycle.
These discs have several disadvantages. Firstly, at least three types of material are used in the construction of the discs, i.e. ceramic material for the beads and two types of plastic material for the disc and the annular float respectively. The resulting high price for a set of two or three of these discs puts them out of reach of many potential users. Secondly, the discs are not designed to be fixed to the machine and may be damaged or lost. It has been found that they often become entangled in the wash load and have to be separated therefrom at the end of the wash.
A further disadvantage is that friction between the beads in the disc is an integral part of the design. This results in wear and a gradual reduction in the size of the beads. Eventually they become small enough to slip through the openings in the discs and are lost with the wash water.
It is accordingly an object of the present invention to alleviate the above difficulties.
SUMMARY OF THE INVENTION
According to the invention there is provided a washing method performed in a washing machine having a wash basket for containing wash water and a wash load, the method including the step of attaching a tile of a ceramic material to the inside of the wash basket so that the tile is exposed to the wash water in the wash basket.
Also according to the invention there is provided a tile of a ceramic material having an outer side and an inner side, wherein the inner side is at least particularly unglazed and including attachment means for attaching the outer side of the tile to the inside of a washing machine.
Further objects and advantages of the invention will become apparent from the description of preferred embodiments of the invention below.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described, by way of examples, with reference to the accompanying drawings, in which:
FIG. 1 is a three-dimensional view of a curved ceramic tile designed to fit the wash basket of a particular washing machine;
FIG. 2 is an end view of the tile of FIG. 1 showing attachment means for the tile according to one embodiment of the invention;
FIG. 3 is an end view of the tile of FIG. 1 showing attachment means for the tile according to another embodiment of the invention;
FIG. 4 is a plan view of the wash basket of a washing machine showing three of the tiles of FIG. 1 attached to the inside thereof;
FIG. 5 is a section along the lines V--V in FIG. 4.
FIG. 6 is a side view of a pair of flat ceramic tiles approximately equal in area to the tile of FIG. 1 for fitting the wash basket of any machine with the same capacity drum as the particular machine for which the tile of FIG. 1 is designed; and
FIG. 7 is a side view of a single tile having the same surface area as the tile of FIG. 1, which can be used instead of the two tiles of FIG. 6 in a machine of the same drum capacity but of a different diameter.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
In FIG. 1 reference numeral 10 generally indicates a ceramic tile for fitting inside the wash basket or tub 12 of a washing machine, as shown in FIGS. 4 and 5.
The tile 10 is curved to correspond with the curvature of the inside of the wash basket 12. In practice the tile 10 can be produced with different curves in order to fit different types of washing machines.
The tile 10 is of a porous ceramic material and the front or concave side 14 thereof is unglazed.
The concave side 14 is further provided with a pattern in the form of a grid of horizontal and vertical grooves or depressions 16 therein for increasing the surface area thereof.
In the present example, the size of the tile 10 is about 4" along the curved edge and about 33/4" along the straight or vertical edge.
In one embodiment, as shown in FIG. 2, a pair of matching adhesive strips 20,22, such as Velcro™ strips, are provided on the convex rear side 18 of the tile 10. In order to facilitate the attachment of the strip 20 to the convex side 18, the side 18 is glazed to provide a smooth, firm surface for an adhesive.
The strips 20,22 preferably cover the entire surface of the convex side 18 of the tile 10.
When the adhesive strips 20,22 are of Velcro™, the one half of the pair, preferably the female, is permanently attached to the side 18 of the tile 10, while the male portion is, in use, permanently attached to the inner surface of the wash basket 12 of the washing machine.
It has been found that the mechanical bond between the two mating Velcro™ surfaces is sufficient to hold the tile 10 firmly in position and that the attachment is unaffected by normal vibration of the washing machine during use and immersion in the wash water. This method of attachment provides for the easy replacement of the tile 10 in the unlikely event that it becomes damaged.
When sold to a consumer, the tile 10 can be provided with the pair of adhesive strips 20,22 in position on its concave side 18. In such a case the outside surface of the strip 22 is provided with an adhesive layer for eventual attachment of the strip 22 to the inside surface of the wash basket 12. A protective covering 24 is provided over the adhesive layer, which covering 24 is removed before attaching the strip 22 to the wash basket 12.
In an alternative embodiment, as shown in FIG. 3, a layer 26 of rubber or other suitable flexible waterproof material is sandwiched between two layers of double-sided adhesive material 28 which are impervious to water. The inner layer of the adhesive material 28 is attached to the concave side 18 of the tile 10, while the outer layer of adhesive material 28 is provided with a cover strip 30 which is removed prior to attachment of the tile 10 to the wash basket 12.
The flexible layer 26 is of sufficient thickness to compensate for any slight irregularities between the surfaces of the tile 10 and wash basket 12.
In yet another embodiment, adhesive material may be provided separately from the tile 10 as part of a kit with instructions for attaching the tile 10 to the wash basket 12.
As shown in FIGS. 4 and 5, three of the tiles 10 are located on the inside wall of the wash basket 12. However, the number of the tiles may be varied depending on the type and size of the washing machine. The tiles 10 are spaced around the circumference of the wash basket 12 and located near the bottom of the wash basket 12 as shown in FIG. 5.
In FIG. 4, reference numeral 31 denotes the agitator of the washing machine. The agitator 31 has been omitted in FIG. 5 for the sake of clarity.
Referring now to FIG. 6, an alternative embodiment of the invention is shown in which a pair of elongate tiles 32 are provided in place of the curved tile 10. In combination the tiles 32 have a surface area equal to the surface area of the tile 10.
The tiles 32 are either flat or have only a slight curvature. Since these tiles are narrow, eg. about 11/2"×5", they can be attached to washing baskets with different curvatures and are therefore more universal in their application. For example, when provided with the attachment means as shown in FIG. 3, the flexibility and compressibility of the flexible layer 26 will be sufficient to compensate for any slight gap between the tile 32 and the curved surface of the wash basket 12.
The total surface area of the active ceramic can be maintained by increasing the number of tiles in the wash basket 12 or by increasing the length of each tile 32 to produce a larger tile 34, as shown in FIG. 7. Thus, the tile 34 can be used in place to the pair of tiles 32 in a machine of the same drum capacity.
The laundry tile according to the invention can be used with both domestic and commercial washing machines.
The tile may be sold in kit form with instructions for installation by the user. Each kit may include two or more tiles for installation in a washing machine.
The tiles may be square, rectangular or any other convenient shape. They may be provided in various sizes to suit particular washing machines.
During use of the tiles, the washing machine is filled as usual with an evenly distributed load and the required settings for water level and temperature of the wash water are selected. For a lightly soiled load, no detergent is usually required. For heavier soiling, a small quantity of detergent may be used, or stains may be pre-treated. The time of the wash cycle may also be increased.
Tests have shown that the amount of detergent required can be reduced by a factor of ten or more for each regular to large size wash load. During the wash cycle, agitation of the water and wash load increases the natural cleaning power of the water, as described above. In addition, friction between the wash load and the patterned surface of the tile assists the cleaning action by loosening dirt from the fabric. These cleaning processes are repeated during the rinse cycle.
If desired, a small amount of vinegar may be added to the rinse water to sanitize and freshen the load and to keep the washing machine and associated pipe work free of scale in hard water, as well as to progressively clear any deposits which may have accumulated during any previous use of large amounts of detergent.
The tiles may be of any convenient size required to provide sufficient total surface area of ceramic for obtaining satisfactory results with the maximum amount of water required for a full load in a particular machine.
The tiles are also of sufficient thickness to withstand breakage.
It is an advantage of the invention that the tiles are automatically cleaned by friction with the wash load each time they are used. The tiles are also inexpensive to manufacture and can be provided to the consumer at a relatively low cost. Due to the elimination of detergent or substantial reduction in the amount of detergent used, further costs savings result, as well as the benefits to the environment.
Although the tiles are indicated as being attached to the sides of the wash basket in the described specific embodiments, they may be attached in any other convenient place which comes into contact with water during a wash or rinse cycle, such as the agitator, drum, basket or pipework.
In the manufacture of the tiles the type of ceramic used may be a standard mix normally used for the manufacture of ordinary tiles, pots, plates, vases or similar items.
Although the ceramic tiles have been found to provide satisfactory results, an additional ingredient, tourmaline, may be added to the ceramic mix or applied to the unglazed working surface of the tile before firing in a kiln to enhance the cleaning action. Tourmaline has pyroelectric and piezoelectric properties which enhance the cleaning action of the ceramic.
While the tile according to the invention has been described with reference to use in a washing machine for washing laundry, it is envisaged that the tile may also be used in other types of washing machines, such as dish washing machines.
The invention also extends to a washing machine provided with a tile according to the invention.
While only preferred embodiments of the invention have been described herein in detail, the invention is not limited thereby and modifications can be made within the scope of the attached claims.
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A washing method performed in a washing machine having a wash basket for containing wash water and a wash load includes the step of attaching a tile 10 of a ceramic material to the inside of the wash basket 12 so that the tile 10 is exposed to the wash water in the wash basket 12. A laundry tile 10 of ceramic material for use in the method is provided. It comprises a front side 14 and a rear side 18, wherein the front side 14 is at least partially unglazed. In one embodiment attachment strips 20,22 are provided for attaching the tile 10 by its rear side 18 to the inside of the wash basket 12 of a washing machine.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The invention relates to the metallurgy of non-ferrous metals, and in particular, to the electrolytic production of magnesium in a continuous process line.
[0003] 2. Description of the Prior Art
[0004] Metallic magnesium is produced by passing direct electric current between anodes and cathodes suspended in facing spaced relation in a molten salt bath containing magnesium chloride, within an enclosed cell chamber. The electrolysis of magnesium chloride in the bath, causes molten magnesium metal to be released at the cathode surfaces while chlorine gas is generated at the anode surfaces. The metal, being lighter than the bath, rises along the cathode surfaces, while the gas rises through the bath in a plume of bubbles from each anode surface to collect in a gas space within a working space above the level of the bath. A solid or semi-solid chlorine-magnesium raw material is utilized in the production of magnesium in the continuous production lines. This raw material is loaded either into a process area of an electrolytic cell or into a special melting device forming a part of the continuous production line. It is typically recommended to load the solid chlorine-magnesium raw material at a surface of a bath in the electrolysis compartment of the cell.
[0005] An example of an apparatus for electrolytic production of magnesium is provided by U.S. Pat. No. 4,308,116. The electrolytic cell disclosed by the patent contains a special section adapted for receiving and melting a solid magnesium chloride. An upwardly extending gas exhaust bell is formed for evacuation of gases from the electrolysis section. The bell includes a feeding pipe for loading a solid raw material.
[0006] A cross-wall extends transversely in the electrolysis compartment. It separates the cathodes in the electrolysis compartment, restricts the treatment time of the non-molten material in the electrolytic section and contributes to the discharging thereof into the metal collecting chamber. In the metal collecting chamber, the non-molten raw material is mixed with the molten metal, resulting in an undesirable solidification of the former. Another important drawback of this patent is that the loading of solid material takes place in the vicinity of the cross-wall. The losses are especially increased when solid carnallite is utilized as a raw material. This is because the required volume of the loaded material per unit of the electrical current intensity is doubled in this case, compared to the loading of magnesium chloride.
[0007] Furthermore, loading of a free flowing solid or semisolid raw material into the area adapted for evacuation of the anode gasses leads to contamination of the gasses by fine particles or of the raw material dust.
[0008] Another example of the electrolytic cell according to the prior art is illustrated in FIG. 1. A section for loading and melting of a solid raw material is formed between two supporting anodes 13 . After loading of the raw material, as illustrated by the arrows, the flow of chlorine gas contaminated by a dust moves directly to a rear wall 29 and a gas discharging outlets 17 . A short distance between the loading area and the gas discharging outlets does not provide enough space for efficient separation of the chlorine gas from the dust particles of the raw material. Thus, the degree of contamination of the aspirated gases within the gas evacuation system is high. Therefore, further utilization of the anode gases in this prior art arrangement requires additional steps of cleaning, which ultimately increases operational costs of the system.
SUMMARY OF THE INVENTION
[0009] One aspect of the invention provides an apparatus for electrolytic production of magnesium including at least one electrolysis compartment and at least one metal collecting compartment separated from each other by a partition wall. A plurality of upright anode elements is interspread with a plurality of cathode elements within the electrolysis compartment. The electrolysis compartment is formed with at least one section for receiving and melting of a substantially solid raw material. Each section is defined between two adjacent receiving anodes and has an elongated loading inlet for directing of the substantially solid raw material. At least one gas discharging outlet is provided for discharging of chlorine gas developed at the plurality of anodes. A baffle is supported by the receiving anodes at ends thereof remote from the partition wall and in the vicinity of the gas discharging outlet. The baffle prevents direct flow of a mixture of chlorine gas and a dust resulted from loading of the substantially solid raw material into the gas discharging outlet. The baffle diverts the flow away from the gas discharging outlet and toward the partition wall prior to entering the gas discharging outlet.
[0010] As to another aspect of the invention, a gap is formed between an end of each receiving anode and the partition wall, so that the mixture before entering the gas discharging outlet passes through gaps between the receiving anodes and the partition wall substantially extending the route of the flow of the mixture and enhancing separation of the chlorine gas from the dust.
[0011] As to a further aspect of the invention, the baffle is formed with top, bottom and side portions. The top portion engages an upper closure of the electrolysis compartment, the side portions are supported by the receiving anodes and the bottom portion is submerged into the electrolyte.
[0012] According to still another aspect of the invention, spaces between two receiving adjacent anodes in each loading and melting section are greater than the spaces between the remaining adjacent electrodes in the electrolysis compartment. Each loading and melting section further includes at least two cathodes positioned between the receiving anodes and spaced from each other at a distance substantially equal to 2-3 average spaces between the remaining adjacent electrodes in the electrolysis compartment. The height of the cathodes in the loading and melting section is about 1.05-1.015 of the remaining cathodes in the electrolysis compartment.
[0013] According to a still further aspect of the invention, the elongated loading inlet is in the form of a pipe-shaped member which is spaced from the rear ends of the anodes in the electrolysis compartment at a distance substantially equal to 0.25-0.33 of the width of the anodes. Each metal collecting compartment is formed with at least one internal cover facing the direction of electrolyte and at least one external cover. The gas aspiration from the area under the internal cover is connected to a system of gas evacuation from the electrolysis compartment. A system of sanitary gas evacuation is located between the external and internal covers.
[0014] The present invention causes increase of the service life of the electrolytic cell which utilizes a solid raw material and reduces the cost of magnesium production. This is due to the increased durability of its structural elements. The lower portion of the curtain or the dividing partition is made of molten-cast materials, such as for example, korvishite. The upper portion of the partition is formed from materials of mullite type or refractory concrete. These materials are less sensitive to heat changes. Korvishite is more resistant to the melts containing impurities of hydrogen chloride.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Other advantages and features of the invention are described with reference to exemplary embodiments, which are intended to explain and not to limit the invention, and are illustrated in the drawings in which:
[0016] [0016]FIG. 1 is a schematic partial top plan view of an electrolytic cell according to the prior art;
[0017] [0017]FIG. 2 is a schematic partial top plan view of the electrolytic cell of the invention;
[0018] [0018]FIG. 3 is a vertical cross section of the electrolytic cell of the invention;
[0019] [0019]FIG. 4 is a partial sectional view of the electrolytic cell of the invention showing a loading and melting section;
[0020] [0020]FIG. 5 is a partial elevational view according to section line 5 - 5 of FIG. 3, and
[0021] [0021]FIG. 6 is a partial section view according to section line 6 - 6 of FIG. 5.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0022] Referring now to FIGS. 1 - 6 wherein the preferred embodiment of the electrolytic cell of the invention for production of magnesium is illustrated. A housing 20 of the electrolytic cell is a refractory wall structure formed with an electrolysis compartment 4 which is separated from a metal collecting compartment 5 by a refractory curtain or partitioning wall 3 . Although one electrolysis and metal collecting compartments are illustrated by the drawings, electrolytic cells with a plurality electrolysis and of metal collecting compartments are within the scope of the invention.
[0023] The curtain wall 3 extends substantially upwardly within the refractory housing of the electrolytic cell from an area at the bottom floor to a top part thereof. The walls and the floor of the electrolytic cell can be made of heavy refractory construction utilizing refractory blocks.
[0024] Each curtain wall 3 contains first operational openings 22 and second operational openings 24 separated by a solid portion of the wall. The first operational openings 22 are provided at an upper region of the curtain wall, whereas the second operational openings 24 are situated at the floor area.
[0025] The electrolysis compartment 4 includes a gas discharge outlet duct 17 at its upper portion for removal of chlorine gas. The electrolysis compartment 4 is enclosed at the top by a refractory lined closure 11 , so as to form a gas-tight seal therebetween.
[0026] A multiplicity of anodes 7 and cathodes 6 form a part of the electrolysis compartment 4 . A plurality of heavy, plate-like graphite anodes 7 are mounted in the top closure 11 , so as to project downward into the electrolysis compartment 4 with their lower edges near the bottom of the latter. Position of each anode is such that its longitudinal dimension extends from the front to the rear of the compartment 4 . As best illustrated in FIG. 2 longitudinally the anodes 7 extend between the partition wall 3 and the rear wall 29 of the sell. A suitable electrical connecting means 8 is provided at the upper ends of the anodes 7 . In addition, cooling means is formed for extracting heat from the anodes. The electrolysis compartment 4 also includes a plurality of cathodes 6 which may consist of steel plates. The cathodes 6 are arranged at localities between successive anodes, so that the electrodes alternate in mutually parallel arrays along the electrolysis compartment. The cathodes 6 also extend longitudinally within the electrolysis compartment. The cathodes that are disposed between pairs of anodes are arranged in spaced pairs and carried by suitable mounting and electrical connecting structure which extends through the wall and has a suitable connection means. The cathodes of each described pair are disposed suitably close to the respective adjacent anodes.
[0027] The walls of the cell are made of heavy refractory construction and can be conveniently built of refractory blocks. The entire structure may have an outer insulating layer and an outer steel casing 1 is provided for strength and protection. At least one gas discharging outlet 17 is provided for discharging of a chlorine gas released at the plurality of anodes 7 . The gas discharging outlets 17 are situated at the rear wall 29 and in the vicinity of the rear ends of receiving anodes 13 .
[0028] Multiple sections 9 adapted for receiving and melting of substantially solid raw materials, such as solid carnallite, are formed within each electrolysis compartment 4 . Each loading and melting section 9 contains two receiving cathodes 12 located between two receiving anodes 13 , so that working surfaces of these cathodes are oriented in the direction of the receiving anodes. An elongated loading inlet 10 is provided for directing of the substantially solid raw material into an area 30 between the supporting anodes 13 .
[0029] The apparatus of the invention utilizes fragmented solid raw material which is subject to additional fragmentation during transportation and loading. Thus, upon loading of the raw material through the elongated loading inlet 10 on the surface of electrolyte in the section 9 , formation of fine dust particles within the receiving area 30 is inevitable.
[0030] Each section 9 contains a baffle 14 situated between the receiving anodes 13 at the ends thereof remote from the partition wall 3 and in the vicinity of the gas discharging outlets 17 . The baffle 14 is formed with top 34 , bottom 36 and side 32 portions. As best illustrated in FIG. 3 and 5 , the top portion 34 of the baffle 14 engages an upper closure 11 of the electrolysis compartment and the side portions 32 are supported by the respective receiving anodes 13 . The bottom portion 36 extends downwardly below the level of the melt or electrolyte. To facilitate installation of the baffle 14 , portions of the receiving anodes 13 facing the rear wall 29 are formed with C-shaped channels adapted for close receiving of the side portions 32 . A refractory adhesive material, such as a refractory glue or cement, is utilized to permanently secure the baffle 14 to the receiving anodes 13 .
[0031] The baffle 14 is typically made of materials resistant to the operational conditions of the electrolytic cell. An example of such materials is a refractory concrete.
[0032] One of the important objects of the invention is to minimize contamination of the discharged chlorine gas by particulates of the raw material. For this purpose, as best illustrated in FIG. 2, the area 30 between the receiving anodes 13 , located above the level of electrolyte, is isolated by the baffle 14 from the rear wall 29 . The structure precludes direct communication between the receiving area 30 and the gas discharging outlets 17 .
[0033] In view of the installation of the baffle 14 in a manner discussed hereinabove, the flow of chlorine gas contaminated by the fine particles of solid raw material or dust is, prior to entering the gas discharging outlets 17 , is directed toward the partition wall 3 , through the passages 31 and along the outer surfaces of the receiving anodes 13 . Such diversion substantially extends the travel passage of the contaminated chlorine gas and enhances separation of the chlorine gas from the dust particles. This ultimately reduces the degree of contamination of the aspirated gases within the gas evacuation system.
[0034] In the preferred embodiment of the invention, the distance “a” between the receiving cathodes 12 in each section 9 (see FIG. 4) does not exceed 2-3 average distances between the remaining electrodes of the electrolysis compartment. Further increase of the distance “a” results in insufficient utilization of the electrodes. However, when the distance “a” is less than two distances between the remaining electrodes in the electrolysis compartment, hydrodynamic resistance to the flow of electrolyte within the vertical channels between the receiving cathodes 12 is substantially increased. This causes undesirable movement of the electrolyte flow in the loading and melting section 9 which brings the non-molten carnallite into the metal collecting compartment 5 .
[0035] The flow of electrolyte does not circulate in the spaces between the electrodes in the loading and melting section 9 in a manner similar to that of the remaining electrolysis compartment. In the loading and melting section 9 , as best illustrated in FIG. 4, the flow of electrolyte is directed upwardly in the spaces between the receiving anodes 13 and the receiving cathodes 12 . The downward movement of the electrolyte is through the channels formed between the receiving cathodes 12 . At the upper region of the cathodes 12 , where the change in the direction of electrolyte flow has taken place, the flow of electrolyte moves within the plane substantially normal to the surfaces of the electrodes.
[0036] Thus, in the section 9 , the flow of the melt does not move toward the metal collecting compartment, but is directed downwardly toward the bottom of the cell within the channel between the receiving cathodes 12 forming suction-type circulation. This circulation contributes to more intensive mixing of the solid raw material or solid carnallite with the melt and enhances the dissolving of the raw material within the bath. This process is optimized when the ratio of the height “c” (see FIG. 4) of the receiving cathodes 12 to the height of the remaining cathodes in the electrolysis compartment 4 is between 1.05-1.15:1.00, respectively.
[0037] Furthermore, to minimize the possibility for the non-molten raw material or carnallite to enter the metal collecting compartment 5 , the loading inlet or branch pipe 10 is positioned in the close vicinity to the rear wall 29 of the cell. In this respect, he elongated loading inlet 10 is positioned at a distance “b” from the rear ends of the anodes (see FIG. 3). In the preferred embodiment of the invention, the distance “b” is between 0.25 and 0.33 of the width of the anodes.
[0038] The rate of the melting of the solid raw material or carnallite is increased by forming the electrical connecting arrangement of the receiving anodes 13 without the cooling means. This is one of the distinctions between the receiving anodes 13 of the loading and melting section 9 , and the remaining anodes 7 of the electrolysis compartment 4 .
[0039] In the electrolysis compartment, the flow of electrolyte moves within the plane substantially parallel to the planes of electrodes. Thus, the Flow of electrolyte carries magnesium through the top operational openings 22 of the curtain wall or refractory partition 3 into the metal collecting compartment 5 .
[0040] The curtain wall or refractory partition 3 is made of various refractory materials. For example, the lower part of the curtain 3 typically submerged into the melt is made of the fused cast materials, whereas mullite or refractory concrete are used to form the upper part thereof surrounded by the gaseous phase.
[0041] As illustrated in FIG. 3, an upper region of each metal collecting compartment 5 is formed with two covers. A lower cover 15 facing the direction of electrolyte is typically made of refractory concrete. An exterior or upper cover 16 is made of a metal such as steel. A system for aspiration of gases from an area of the metal collecting compartment 5 below the lower cover 15 is connected with the system of gas evacuation of the electrolysis compartment 4 . The inlet 18 to a system of sanitary gas evacuation is located within a space between the upper 15 and lower 16 covers of the metal collecting compartment 5 .
[0042] In operation of the apparatus of the invention, the electrolysis compartment 4 is filled to a predetermined level with the electrolyte or electrolytic bath containing magnesium chloride. By means of a suitable source of energy, a direct electric current is passed through the bath between the working surfaces of the anodes 7 and cathodes 6 facing each other. Continuous passage of the electrical current results in electrolysis of the molten chemicals. Free magnesium metal is deposited in the molten state on the surfaces of the cathodes 6 . Since the magnesium metal is lighter than the bath, it flows upwardly along the working surfaces of the cathodes to be ultimately received and accumulated in the collecting compartment 5 . Simultaneously, the chlorine gas is continuously evolved at the anodes 7 and rises from the anodes to be collected in a gas space above the electrolysis compartment 4 and is discharged through the port or gas discharging outlets 17 .
[0043] Chlorine gas released at the anodes 7 upon reaching a top surface of the electrolyte, is separated therefrom and evacuated from the electrolysis compartment through the discharging outlets 17 of the gas evacuation system. The discharging outlets in the form of the branch pipes 17 are located at the rear wall 29 of the cell.
[0044] Magnesium which is carried out into the metal collecting compartment 5 by the flow of electrolyte appears on the surface of the melt and is periodically taken out during individual maintenance of the cells. When the continuous production technology is utilized, magnesium can be transported into the special storage facility. The electrolyte from the metal collecting 5 is returned back through the lower operational openings into the electrolysis compartment 4 .
[0045] Bubbles of the chlorine gas are carried out along with electrolyte and magnesium flow from the electrolysis compartment 4 into the metal collecting compartment 5 . This chlorine is aspirated through the gas discharging outlets 17 into the system of gas evacuation from the electrolysis compartment 4 .
[0046] The metal collecting compartment 5 is open and communicates with atmosphere when, for example, the slime is removed from the electrolytic cell. During this time the outlet 18 is disconnected from the system of gas evacuation from the electrolytic section 4 . Upon reaching the metal collecting compartment 5 , the chlorine gas is aspirated into the system of sanitary evacuation, so as to deliver the chlorine gas to the cleaning facilities.
[0047] Thus, utilization of the electrolytic cell of the invention for the production of magnesium enables the user to reduce the metal losses and to increase the quality of anode chlorine gas. This substantially reduces the production costs of magnesium metal.
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An apparatus for electrolytic production of magnesium includes a plurality of upright anode elements interspread with a plurality of cathode elements situated within at least one electrolysis compartment. At least one section, defined between two adjacent anodes and having an elongated loading inlet, is provided for receiving and melting of a substantially solid raw material. A gas discharging outlet is formed for discharging of chlorine gas developed at the plurality of anodes. A baffle is supported by the receiving anodes in the vicinity of the gas discharging outlet. The baffle prevents direct flow of a mixture of chlorine gas and fine dust particles resulted from loading of the solid raw material between the section and gas discharging outlet.
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CROSS REFERENCE TO RELATED APPLICATION
This is a continuation-in-part of application Ser. No. 09/239,131 filed Jan. 28, 1999 entitled “Advanced Case Carburizing Secondary Hardening Steels” now U.S. Pat. No. 6,176,946 issued Jan. 23, 1999 which is a continuation of Provisional Application Serial No. 60/072,834 filed Jan. 28, 1998 entitled “Method for Design of Transformation Temperatures in Steels”, and for which priority is claimed with respect to said applications.
ACKNOWLEDGMENT OF FUNDING
The original subject matter of the parent application was funded, at least in part, by the Army Research Office, Grant No. DAAH04-96-1-0266. The subsequent continuation-in-part subject matter herein was not funded by Grant No. DAAH04-96-1-0266.
BACKGROUND OF THE INVENTION
This invention relates to a new class of steel alloys especially useful for the manufacture of case hardened steel gears and other products, in particular, blades such as skating blades made from case hardened steel alloys.
Currently, there are a number of high performance steels on the market. Many of these materials utilize primary carbides to achieve high surface hardness and others use stage one or stage three tempered conditions with epsilon carbide or cementite strengthening. Primary carbides are formed when the carbon content exceeds the solubility limit during the solution treatment, and large alloy carbides precipitate. This is the case for secondary hardening steels using alloy carbide strengthening for greater thermal stability to improve properties such as scoring resistance.
However, primary carbide formation can have a detrimental impact on both bending and contact fatigue resistance. Formation of primary carbides can also make process control difficult for avoidance of undesirable carbide distributions such as networks. In addition, primary carbide formation in current steels can lead to a reversal in the beneficial residual compressive stresses at the surface. This is due to a reversal of the spatial distribution of the martensite start temperature due to the consumption of austenite stabilizing elements by the primary carbides. In applications of sliding wear, the formation of primary carbides can be beneficial; however, in current steels this can lead to a reversal in the beneficial residual compressive stresses at the surface due to the consumption of elements promoting hardenability by the primary carbides.
Thus, there has developed a need for case hardenable steel alloys which do not rely upon primary carbide formation, but which provide secondary hardening behavior for superior thermal stability. This invention provides a new class of steel alloys meeting this requirement. while exploiting more efficient secondary hardening behavior to allow higher surface hardness levels for even greater improvements in fatigue and wear resistance. Rolls for manufacturing processes utilizing such steels are projected to have more uniform and enhanced performance characteristics derived through simplified manufacturing technologies and to also have performance characteristics which are more predictable and reproducible.
SUMMARY OF THE INVENTION
Briefly, the present invention comprises a class of case hardenable steel alloys in the form of roll form dies with carbon content in the range of about 0.05 weight percent to about 0.24 weight percent in combination with a mixture of about 15 to 28 weight percent cobalt, 1.5 to 9.5 weight percent nickel, 3.5 to 9.0 weight percent chromium, up to 3.5 weight percent molybdenum, and up to 0.2 weight percent vanadium.
The microstructural features are a Ni—Co lath martensite matrix steel strengthened by M 2 C carbides typically containing Cr, Mo and V. Typical processing of this class of steels includes case carburizing, solution treatment, quenching, and tempering, although due to the high alloy content, quenching may not be required. Case carburizing produces a gradient in the volume fraction of the M 2 C carbides and results in a concomitant increase in hardness and promotes a surface residual compressive stress. The efficiency of the M 2 C strengthening response allows this class of steels to achieve very high surface hardnesses with limited soluble carbon content. Thus, this class of steels have the ability to achieve very high surface hardnesses without the formation of primary carbides.
Typical advantages of this class of alloys include ultrahigh case hardness leading to superior wear and fatigue resistance, superior core strength and toughness properties, optional air hardening resulting in less distortion, and higher thermal resistance.
This new class of secondary hardening steels are matrix steels utilizing an efficient M 2 C precipitate strengthening dispersion. Because of the efficiency of this strengthening dispersion, a superior combination of properties can be attained for many applications on a situation by situation and product by product basis. For example, in situations where the desired surface properties are similar to current materials, the core strength and toughness can be superior. In applications where superior surface properties are desired, the disclosed steels can easily outperform typical materials while maintaining normal core properties, and in applications which require corrosion resistance, these new steels can provide stainless properties with surface mechanical properties similar to typical non-stainless grades.
Thus, an object of the invention is to incorporate desirable properties resulting from the class of alloys disclosed in various products.
A further object of the invention is to provide roll form dies made from case hardened steel alloy materials wherein the surface hardness of the dies surface and the core hardness of the dies are controlled to maximize performance and to provide uniform and reproducible characteristics.
Another object is to provide die forms for rolling made from steel alloy materials disclosed wherein the flexibility, hardness, sharpness of the blade and other blade characteristics are controllable and reproducible.
These and other objects, advantages and features of the invention will be set forth in the detailed description which follows.
BRIEF DESCRIPTION OF THE DRAWING
In the detailed description which follows, reference will be made to the drawing comprised of the following figures:
FIG. 1 is a graph correlating hardness to precipitation driving force for experimental and predicted results;
FIG. 2 is a graph correlating precipitation half completion time and half completion coarsening rate constant for experimental and predicted results;
FIG. 3 is a graph which correlates calculated segregation free energy difference with experimental embrittlement potency;
FIG. 4 is a flow block diagram of the total system structure of the alloys of the invention;
FIG. 5 is a graph depicting the relationship between cobalt and nickel content for a 200° C. Ms temperature for the alloys of the invention;
FIG. 6 is a pseudo-ternary diagram as a function of chromium, molybdenum and vanadium at 0.55 weight percent carbon with regard to alloys of the invention at 1000° C.; and
FIG. 7 is a graph comparing hardness of the steel alloys of the invention with conventional carburized alloys.
FIG. 8 is a graph containing Falex wear test data for steel alloys of the invention in comparison with conventional 8620 steel.
FIG. 9 is a graph of NTN 3 ball-on-rod rolling contact fatigue data for alloys of the invention in comparison with conventional M50 bearing steel;
FIG. 10 is an isometric view of a typical roll form die fabricated from a carburized case hardened steel alloy; and
FIG. 11 is a cross-sectional view of the die of FIG. 10 taken along the line 11 — 11 .
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The steel alloys of the invention were developed using various modeling techniques followed by experimental confirmation or testing. An important component of the modeling is the application of a thermochemical data bank and software system. The system or program employed uses thermodynamic assessments from binary, ternary, and quaternary systems to extrapolate to higher order multicomponent systems. Equilibria, constrained equilibria, and driving forces can be calculated as functions of composition, chemical potential, as well as other user defined functions. To apply this information to the modeling of highly nonequilibrium processes of interest in real alloys, the dynamic nature of phase transformations in terms of thermodynamic scaling factors are described and then evaluated by the thermochemical software. Thus, hypothetical steel compositions were the subject of an initial computational model involving the precipitation of M 2 C carbides leading to a secondary hardening response in ultrahigh-strength steels. A second effort employed a published thermodynamics-based model for the non-linear composition dependence of the martensite start temperature. A third modeling effort involves the application of quantum mechanical calculations to the production of hypothetical compositions with the goal of achieving improved resistance to hydrogen embrittlement and intergranular fracture. Modeling techniques were then followed by testing of the optimized alloys. Following is a discussion of modeling technique considerations.
Secondary Hardening
Ultrahigh-strength (UHS) secondary hardening steels are strengthened by the precipitation of coherent M 2 C carbides during tempering. In high Co steels in which dislocation recovery is retarded, the M 2 C carbides precipitate coherently on dislocations and provide the characteristic secondary hardening peak during tempering. A wide range of techniques are utilized to gather experimental information across a complete range of size and time scales of interest. Atom-probe field-ion microscopy (APFIM), transmission electron microscopy (TEM), small angle neutron scattering (SANS), and X-ray diffraction (XRD) techniques provide information on the size, shape, composition, and lattice parameters of the M 2 C precipitates as well as the resulting hardness values spanning tempering times of less than an hour to more than a thousand hours. This study identified that the precipitation was well described by a theory developed by Langer and Schwartz for precipitation at high supersaturation in which the growth regime is suppressed and precipitation occurs by a process of nucleation and coarsening, maintaining a particle size close to the critical size.
Based on these investigations, two important scaling factors are identified. The initial critical nucleus determines the size scale of the precipitates throughout the precipitation reaction and the coarsening rate constant determines the precipitation time scale. The peak hardness in an ultra high strength steel commonly occurs at the particle size corresponding to the transition from particle shearing to Orowan bypass. It is also advantageous to bring the M 2 C precipitation to completion in order to dissolve all of the transient cementite which otherwise limits toughness and fatigue life. Therefore, the smaller the initial critical particle size, the closer completion of precipitation occurs to peak hardness and more efficient strengthening is obtained. The time scale of precipitation is also important due to the kinetic competition between the secondary hardening reaction and the segregation of impurities to the prior austenite grain boundaries leading to intergranular embrittlement.
The initial critical nucleus size scales inversely with the thermodynamic driving force for precipitation. In the case of the M 2 C carbide it is important to include the influence of prior cementite formation and coherency on this quantity. The coherency elastic self energy can be evaluated by the calculation of an anisotropic ellipsoidal inclusion using the equivalent Eigenstrain method and the impact of solute redistribution on the resulting stress distribution is addressed by using open-system elastic constants. By relating the coherency strain to composition via the compositional dependence of the particle and matrix lattice parameters, the composition dependence of the elastic self energy is determined in a form compatible with the thermodynamic software. The linear elastic self energy calculation represents an upper limit and a correction factor is used to fit the precipitation composition trajectories of a large set of experimental alloys.
The impact of prior cementite precipitation is accounted for by the calculation of the coherent driving force in the presence of the carbon potential due to para-equilibrium cementite. This para-equilibrium carbon potential is defined by an equilibrium between the matrix and cementite in which the substitutional species are held constant and only the interstitial carbon is allowed to partition. In this approximation the cementite acts as a carbon source at constant chemical potential.
FIG. 1 represents the level of agreement of the strengthening response of the model alloys with the above model. The model alloys contain 16 wt % Co, 5 wt % Ni, and 0.24 wt % C with varying amounts of the carbide formers Cr, Mo, and, in a few cases, V. The nickel content is chosen to eliminate austenite precipitation during tempering which otherwise complicates the hardening response. In FIG. 1, the peak hardness during tempering at 510° C. is plotted against the driving force for precipitation of the coherent M 2 C carbide in the presence of para-equilibrium cementite. The open circles represent alloys containing V. The relationship demonstrates the ability to predict peak hardness values within approximately +/−25 VHN in this class of alloys.
The time scale of precipitation at high supersaturations, according to the Langer-Schwartz treatment, scales with the coarsening rate of the particle distribution. The modeling pursued in this work expands upon the Lifshitz-Slyozov and Wager (LSW) theory, describing the coarsening of spherical particles in a binary system, with the intent of removing the binary restrictions of the LSW theory and reformulating it in a manner compatible with the multicomponent thermodynamics of the software and data bank system.
The result of this analysis characterizes the coarsening rate of a particle of average size as a function of the multicomponent diffusion coefficients, the equilibrium partitioning coefficients, and the second derivatives of the Gibbs free-energy evaluated at the equilibrium state. The surface energy and molar volume are taken to be composition independent and are considered constant. In this form, the coarsening rate constant is the result of an asymptotic analysis and is only representative at very long time scales and very close to equilibrium. This is certainly not the case for the precipitation of the M 2 C carbide at high supersaturation. The matrix content of alloy is far from equilibrium during much of the precipitation process, approaching equilibrium only near completion. This effect is more severe for alloys containing stoichiometric quantities of carbide formers as measured by the relative difference in the matrix alloy content during precipitation and at equilibrium.
During precipitation in a stoichiometric alloy, the alloy matrix content is of the same order as the overall alloy content, while at equilibrium, the matrix alloy content is very small. To define a coarsening rate constant more representative of the conditions present during the precipitation process, a coarsening rate is evaluated at the point when the volume fraction of the precipitate is one-half of the equilibrium value. This is achieved by calculating the coherent equilibrium for the M 2 C carbide, and then, adding energy to the M 2 C phase to account for capillarity until the amount of the phase is half of the equilibrium value. The coarsening rate is then calculated from the thermodynamic properties of this state. FIG. 2 represents the correlation between the precipitation half-completion time and the half-completion coarsening rate constant of the model alloys for which this data is available.
Ms Temperatures
To predictively control the spatial distribution of martensite-start (Ms) temperatures in the carburized steels to achieve fully martensitic structures with controlled residual stress distributions, a published model was employed. The thermodynamics-based nucleation-kinetic model was calibrated to the composition-dependence of measured Ms temperatures using both literature data and assessments of experimental multicomponent alloys.
Interfacial Cohesion
Intergranular embrittlement phenomena such as hydrogen embrittlement are undesirable in the intended alloys. Embrittlement of ultrahigh-strength steels is associated with the prior segregation to the grain boundary of impurities such as P and S. A thermodynamic treatment of this phenomenon by Rice and Wang illustrates that the potency of a segregating solute in reducing the work required for brittle fracture along a boundary is linearly related to the difference in the segregation energy for the solute at the boundary and at the free surface. Specifically, a solute with a higher segregation energy at the free surface will be an embrittler while a solute with a higher segregation energy at the grain boundary will enhance intergranular cohesion. A survey of reported segregation energies and embrittling potency (reported as the shift in the ductile-to-brittle transition temperature per atomic percent solute on the grain boundary) in Fe-base alloys demonstrates these general trends; however, the experimental difficulty of surface thermodynamic measurements gives ambiguous values for some solutes.
First principle calculations were used to determine the total energy of atomic cells representing the Fe Σ3[110](111) grain boundary and (111) free surface with a monolayer of an impurity solute present. The calculations were accomplished with the full-potential linearized plane wave (FLAPW) total energy technique. The atomic structure in each case was relaxed to find the minimum energy state. The results of these calculations include not only the segregation energies responsible for the embrittling or cohesion enhancing effects of segregating solutes, but the underlying electronic structure of the solutes in the boundary and surface environments. A comparison of the directional covalent electronic structure between B, a strong cohesion enhancer, and P, a strong embrittler, indicates the strong bonding of the B atom across the boundary plane associated with hybridization of the B 2p electrons with the Fe d band. This directional bonding is not seen in the case of the P atom which does not significantly hybridize with Fe.
The results of the first principle calculations were correlated to the experimental embrittling potency in FIG. 3 . The difference between grain boundary and free surface segregation energies, calculated by electronic structure calculations, and the experimentally observed shift in the ductile-to-brittle-transition-temperature are plotted for C, B, P and S solutes. The C and B are shown as cohesion enhancers, P and S as embrittlers. The computed energy differences are in excellent agreement with the observed effects on interfacial cohesion.
MATERIALS DESIGN
Background
Design considerations for high performance rolls for various applications include the desire to provide very high surface hardness while maintaining material ductility for shock and flow tolerance. Critically, the portion of the tool (die) which contacts the work surface must be very high, i.e., greater than 58 Rockwell C hardness. Heretofore, monolithic tool steels with a hardness ranging from about 58 to 62 Rockwell C hardness have been used. However, such steels are brittle and do not exhibit a long term work life span. Alternatively, a reduced hardness alloy may be coated with wear resistant or hard coatings to improve tool life and surface lubricity. This involves potentially expensive coating techniques. The alternative of the present invention provides benefits not available from these prior techniques. It involves case hardening by carburizing or nitriding an alloy taken from a special group of alloys in the form of the roll form die wherein the form is hardened greater than about 58 Rockwell C with the core maintained at a lesser hardness and wherein the surface is hardened at a depth of at least about 1 millimeter in the region of the die wear surface. The core is typically less than about 53 Rockwell C.
Punch dies may also be made in accord with the described procedure and formulation. The work surface will again be case hardened by a carburizing process typically of the select steel disclosed thereby providing a gradient between a 1 to 3 millimeter layer of high hardness (<62 Rockwell C) work surface and a relatively softer core or tool matrix (typically >53 Rockwell C).
Analysis
The systems analysis of the case-core secondary hardening steel system is the first step in the design process. FIG. 4 illustrates the total processing/structure/properties/performance system structure for high power-density gears manufactured by three alternative processing routes, conventional forged ingot processing, near net shape casting and powder processing. Case hardenable secondary hardening gear steels are a subsystem of this flow-block diagram and are the focus of this disclosure. The sequential processing steps dictate the evolution of the case and core microstructures which determine the combination of properties required for the overall performance of the system. Both the case and core consist of microstructures of a martensite with high Co, for dislocation recovery resistance essential for efficient secondary hardening, and Ni, for cleavage resistance. Strengthening is provided by the coherent precipitation of fine M 2 C carbides on dislocations. This secondary hardening reaction dissolves the transient cementite and it brings the precipitation reaction to completion in order to eliminate cementite for high toughness and fatigue resistance. The grain refining dispersion has a double impact on toughness. By limiting grain growth at high temperature during solution treatment, brittle intergranular modes of fracture are inhibited.
The grain refining particles also play an important role in the ductile microvoid nucleation and coalescence fracture behavior. Thus, it is desired to preserve adequate volume fraction and size to pin the grain boundaries while choosing the phases with greatest interfacial cohesion. Also desirable is the control of the grain boundary chemistry to avoid intergranular embrittlement (such as by hydrogen embrittlement) in association with prior segregation of embrittling impurities. During tempering, impurities segregate to the grain boundaries and in the case of P and S reduce the interfacial cohesion of the boundary promoting intergranular embrittlement. A number of methods are used to avoid this problem. Gettering compounds can be utilized to tie up the impurities in stable compounds reducing the segregation to the grain boundary. In order to produce the most stable compounds, however, rapid solidification processing is required. Within their solubility limits, additional segregants such as B can be deliberately added to enhance intergranular cohesion, and the precipitation rate for the secondary hardening reaction can be increased to limit the time at temperature for harmful grain boundary segregation.
Design
As a first design step, core and case carbon levels required for the desired hardness are estimated. This is done by fitting data for existing secondary hardening Ni—Co steels to an Orowan strengthening model and extrapolating to the desired strength. It is estimated that a core carbon content of 0.25 wt % and a case carbon content of 0.55 wt % is needed to provide the desired core and case hardness in this Ni—Co steel.
The next step is to determine the matrix composition of the Fe, Ni, and Co. In order to produce the desired lath martensite morphology, an M s temperature of 200° C. or above is required. Using the nucleation kinetic model for the compositional dependence of the M s temperature, the variation with Ni and Co content is determined. This result is illustrated in FIG. 5 for the case carbon content using a preliminary composition of carbon formers equal to 5 wt % Cr, 0.5 wt % Mo and 0.0 wt % V. Since the case has a higher carbon content than the core, the core will possess a higher M s temperature than the case. In FIG. 5 the Co and Ni content required to fix the s M temperature at 200° C. is indicated. Since a high Ni content is desired to avoid cleavage fracture, a composition containing 25 wt % Co was chosen. This allows the highest possible Ni content, approximately 3.5 wt %, to be used. These calculations are later repeated for consistency when the composition of the carbide formers is further refined.
To define the optimal composition of the carbide formers a number of design constraints are applied. The total amount of carbide formers in the alloy must be greater than that required to consume the carbon present in the case. This lower limit insures that, at completion, embrittling cementite is completely converted to M 2 C carbide. In order to reduce grain boundary segregation, the precipitation rate is maximized. This allows the shortest possible tempering time. The coherent precipitation driving force is maximized to provide a small critical particle size for the M 2 C and more efficient strengthening. Finally, the solution temperature is limited to 1000° C. This allows Cr, Mo and V containing carbides such as M 23 C 6 , M 7 C 3 , MC and M 6 C to be dissolved at reasonable processing temperatures while maintaining very fine scale TiC carbides to act as the grain refining dispersion.
Calculations for the precipitation rate constant indicate low Mo compositions are favorable, while driving force calculations have demonstrated the highly beneficial effect of higher V contents. The solubility constraints are presented by the diagram in FIG. 6 . Here the equilibrium phase fields at 1000° C. are given as a function of Cr and V content. The Mo content is determined by the stoichiometry requirements, the matrix composition is taken from the earlier calculations, and the carbon content represents the case composition. The point on the diagram within the single phase FCC field that maximizes the V content and minimizes the Mo content represents the compromise fulfilling the design criteria. This composition is 4.8 wt % Cr, 0.03 wt % Mo, and 0.06 wt % V. A recalculation of the matrix composition using the final carbide formers results in an alloy composition of Fe —25 Co—3.8 Ni—4.8 Cr—0.03 Mo—0.06 V—0.55 (case)/0.25 (core) C (in wt %). Consistent with the model predictions of FIG. 3, a soluble boron addition of 15-20 ppm is added to enhance intergranular embrittlement resistance.
Examples
A 17 lb. vacuum induction heat of the above composition was prepared from high purity materials. The ingot was forged at 1150° C. in a bar 1.25″ square by 38″ long. The M s temperature of the alloy was determined from dilatometery and found to agree with model predictions. The solution treatment response of the alloy was determined from hardness measurements in the stage I tempered condition. The optimum processing conditions for the core material was determined to be a 1050° C. 1 hour solution treatment followed by an oil quench and a liquid nitrogen deep freeze. After optimal solution treatment, a 12 hour temper at 482° C. results in the desired overaged hardness of 55 R c for the core material. The material was then plasma carburized and processed using these parameters. The C potential, temperature and time used in the carburizing treatment were determined from simulations with multicomponent diffusion software to provide the target surface carbon content of 0.55 wt % and a 1 mm case depth. The curve labeled C 2 in FIG. 7 represents the hardness profile achieved for the carburized sample. A surface hardness of 67 HR c and a case depth of 1 mm are obtained.
Using techniques and processes of this nature, the following alloys set forth in Table 1 were developed and tested:
TABLE 1
Alloy
Fe
Co
Ni
Cr
Mo
V
C (Core)
A1
Bal.
18
9.5
3.5
1.1
0.08
0.20
C2
Bal.
25
3.8
4.8
0.03
0.06
0.237
C3
Bal.
28
3.25-3.15
5.0
1.75-2.50
0.025
0.05-0.18
CS1
Bal.
15
1.5
9.0
0.0
0.2
0.05-0.20
The first, A 1 , is targeted as a replacement for current gear materials in applications where component redesign is not feasible but higher core strength and toughness is needed. As such, A 1 has surface wear properties similar to current commercial properties, but possesses superior core toughness and strength 54 HRC and a K IC of>75 Ksiin. The second alloy C 2 corresponds to the prototype alloy just described. The third alloy, C 3 , pushes the surface properties s far as possible while maintaining adequate core strength and toughness. As also shown by the hardness profiles of FIG. 7, the alloy has reached a surface hardness corresponding to HRC 69 . Wear tests for the carburized material in a standard Falex gear simulator show much reduced weight loss compared to standard carburized 8620 steel in FIG. 8. A ball-on-rod rolling contact fatigue test (NTN type) conducted at 786 ksi Hertzian contact stress indicates an order of magnitude increase in L 10 fatigue life compared to M50 bearing steel as shown in FIG. 9 . The fourth alloy in Table 1, CS 1 , represents a stainless variant of this class of alloy. Targeted to match the surface properties of standard non-stainless gear and bearing materials with sufficient core strength and toughness, the alloy has achieved corrosion resistance better than 440C by anodic polarization conducted in distilled water with a neutral ph. (sucrose added for electrical conductivity). Similar relative behaviors were demonstrated in 3.5% NaCl solution. In salt fog tests, CS 1 outperformed 440C and commercial carburizing stainless steels, the performance gap widened when the tests were completed on samples in the carburized condition. The carburized alloy achieved surface mechanical properties equivalent to A 1 while maintaining corrosion resistance. In RFC tests of the type represented in FIG. 9, both A 1 and CS 1 showed L 10 fatigue life equal or superior to the M50 bearing steel. The table (Table 2) below summarizes the performance achieved in the four alloys:
TABLE 2
Rolling
Contact
Core
Core
Surface
Bending
Fatigue 5
Corrosion
Alloy
Hardness 1
Toughness 2
Hardness 3
Fatigue 4
L 10
Resistance 6
A1
54 Rc
≧75 ksi✓in
>61 R c
≧EN36C
≧M50
NA
C2
≦58 R c
adjustable
67 R c
NA
in process
NA
C3
≦59 R c
adjustable
69 R c
NA
10 × M50
NA
CS1
≦53 R c
≧25 ksi✓n
63 R c
NA
≧M50
>440C
adjustable
1 Hardness determined by ASTM E18.
2 Core toughness determined by ASTM E813.
3 Surface hardness determined by E384.
4 Bending fatigue determined using 4-point bend testing.
5 Rolling contact fatigue determined by NTN 3 ball-on-rod techniques.
6 Corrosion resistance determined by anodic polizations and salt for testing.
Each alloy has a surface hardness exceeding and core hardness exceeding prior art compositions achieved at a lower cost. Variants of the disclosed alloys are set forth in Table 3 (Nominal Compositions in wt. %):
TABLE 3
Alloy
Fe
Co
Ni
Cr
Mo
V
C (Core)
A1 (modified)
Bal
18
9.5
3.5
1.1
0.08
0.16
C3 (modified)
Bal
27.8-28.2
2.9-3.1
5.0-5.2
2.4-2.6
0.18-.025
0.07
CS1 (modified)
Bal
15
1.5
9.0
0.2
0.08
The variants are considered equivalent to the unmodified alloys of Table 1 and are within the class of alloys comprising the alloys of the invention.
It has also been discovered that the disclosed alloys may be subjected to a nitriding process as well as a carburizing process and other case hardening processes such as induction heating to enhance surface hardness. For example the alloy C 3 set forth above may be nitrided during the tempering step to increase surface hardness by 10% or more.
FIGS. 10 and 11 depict the incorporation of steels of the type discussed above in a die. Various types of dies may be fabricated using the described steels, including roll form dies as well as punch dies. Sheet forming dies may also be made using the described steels.
FIG. 11 illustrates in cross section, a typical construction of such a die 48 wherein the curved surface 50 comprises the hardened portion of the die 48 inasmuch as the curved or shaped surface 50 engages the material which is being shaped by the die. Besides carburizing, nitriding, induction hardening, other surface modification techniques may be used followed by heat treatment to produce the desired case and core properties. The result is in a very high hardness for the surface, particularly in high wear areas as well as beneficial residual compressive stresses. The strength of the core can also be controlled to provide sufficient strength to withstand the internal body stresses applied to the tool. The lower hardness of the core also provides improved flaw tolerance and ductility. As a result, the tool has significantly longer useful life.
Referring to FIG. 10, there is illustrated a representation of a roll form die 48 . Die 48 typically includes a shaped form or surface 50 which is engaged against a material (not shown) which is to be formed or shaped by the die 48 . Typically, the die 48 is incorporated in or defines a roll and rotates as depicted by the arrow in FIG. 10 against the material to shape and form the material. The surface 50 desirably has a hardness greater than 58 Rockwell C and a case depth of preferably more than about 0.1 millimeter. More preferably, the surface hardness exceeds 65 Rockwell C and the depth of the case of the hardened die is greater than about 1 millimeter and preferably in the range of about 1 to 3 millimeters. The surface may be hardened by carburizing, nitriding, induction heating or other methods to improve the strength of the material at the surface and thereby achieve case hardening.
Importantly, the core of the die has a lower hardness in the range of less than about 53 Rockwell C. This improves the wear and fatigue resistance at the surface while maintaining a lower hardness core which is ductile. Thus, there is a gradient in hardness with respect to the surface and core with the high hardness surface providing high wear and fatigue resistance while the ductile core provides shock and flaw tolerance. Also, the compressive residual stresses in the case improve the contact and bending fatigue resistance at the surface which can otherwise lead to premature failure of the tool.
FIG. 11 illustrates in cross section, a typical construction of such a die 48 wherein the curved surface 50 comprises the hardened portion of the die 48 inasmuch as the curved or shaped surface 50 engages the material which is being shaped by the die. Besides carburizing, nitriding, induction hardening, other surface modification techniques may be used followed by heat treatment to produce the desired case and core properties. The result is in a very high hardness for the surface, particularly in high wear areas as well as beneficial residual compressive stresses. The strength of the core can also be controlled to provide sufficient strength to withstand the internal body stresses applied to the tool. The lower hardness of the core also provides improved flaw tolerance and ductility. As a result, the tool has significantly longer useful life.
Of course, the drawing depicts a roll form die but other types of dies including punch dies, sheet fabrication dies and the like may be fabricated. It is noted that with roll form dies, the resultant die and the process of using the die provides improved wear, notch bending, fatigue resistance and contact fatigue resistance as well as shock and flaw tolerance. Similar benefits are observed with sheet fabrication and punch dies. The dies exhibit a longer useful life and can be used to produce more complex shapes as well as punch or form higher aspect ratio features. These benefits provide that a single die may be utilized to provide more complex shapes and cuts.
Various aspects of the invention may therefore be altered without changing the form and scope of the invention. Thus, the invention is to be limited only by the following claims and equivalents thereof.
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Steel alloys susceptible to case and core hardening comprise 0.05 to 0.24 weight percent carbon; 15 to 28 weight percent cobalt and 1.5 to 9.5 weight percent in nickel, small percentages of one or more additives: chromium, molybdenum, and vanadium; and the balance iron. Carburized roll form and punch dies made from case hardened steel alloys with a reduced hardness core provide high wear and fatigue resistance as well as improved contact and bending fatigue resistance thereby avoiding premature failure and extending the useful life of such dies.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention pertains to a dispensing head and a method of dispensing for providing increased carbonation in a dispensed fountain soft drink.
2. The Prior Art
F. L. AUSTIN U.S. Pat. No. 4,549,675 has a post-mix carbonated beverage dispensing head with discrete pathways for water and syrup which both lead to a mixing nozzle. This particular dispensing head is available with two types of volumetric flow rate control for the water. The first type is a fixed elastomeric washer and the second type is a movable piston in a sleeve with an adjustable biasing spring.
The highest level of carbonation that has been obtainable from this dispensing head has been 3.6 volumes of carbon dioxide. More carbonation is wanted and needed, particularly with the most popular cola beverages.
OBJECTS OF THE INVENTION
It is an object of the present invention to provide an improved apparatus for and method of increasing the carbonation of a fountain dispensed beverage.
It is an object of the present invention to provide in a carbonated water dispensing head having discrete passageways and normally closed valves, the improvement for increasing carbonation of a toroidal carbonated water decompression chamber upstream of the normally closed valve.
It is an object of the present invention to provide a carbonated beverage dispensing system having a dispensing head with syrup and carbonated water passageways with inlets and normally closed valves, a volumetric flow rate control for the water, and a carbonated water decompression chamber in-between the inlet and the water valve.
It is an object of the present invention to provide a method of increasing carbonation in a dispensed beverage by firstly controlling the volumetric flow rate of carbonated water, then decompressing the carbonated water, and then feeding the decompressed water through a normally closed valve and a nozzle with a receptacle.
SUMMARY OF THE INVENTION
In a carbonated water dispensing head having a carbonated water inlet port, flow control housing, flow control piston, water feed port from the housing to a normally closed valve, and an outlet from the valve to a nozzle, the improvement of a toroidal carbonated water decompression chamber between the flow control piston and the normally closed valve.
A carbonated beverage dispensing system has a dispensing head with syrup and carbonated water inlets, a syrup passageway leading to a nozzle, a carbonated water passageway leading to the nozzle, a normally closed valve in each passageway, a volumetric flow rate control in the water passageway, and a carbonated water decompression chamber downstream of the flow control and upstream of the water valve.
A method of increasing the carbonation of fountain dispensed carbonated water having the steps of providing carbonated water at a propellant pressure volumetrically controlling the rate of water flow, decompressing the carbonated water after controlling the rate of flow, and then feeding the decompressed carbonated water to and through a normally closed valve and to a nozzle and into a receptacle.
Many other advantages, features and additional objects of the present invention will become manifest to those versed in the art upon making reference to the detailed description and accompanying drawings in which the preferred embodiment incorporating the principles of the present invention is set forth and shown by way of illustrative example.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an elevational view in section of the preferred embodiment of the structure of the present invention; and
FIG. 2 is a top plan view of the structure of FIG. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENT
According to the principles of the present invention a carbonated beverage dispensing head is provided as shown in FIG. 1 and which is generally indicated by the numeral 10. A preferred specific example of a complete dispensing head is the subject of F. L. AUSTIN U.S. Pat. No. 4,549,675 of Oct. 29, 1985, which is incorporated into this application by reference thereto. The basic structural components of the dispensing head 10 include a carbonated water passageway extending through head 10 which passageway includes an inlet port 14 having an inlet connecting end 14a connectible to a source of pressurized carbonated water (not shown), and an outlet water feed port 15. There is also provided a discrete syrup passageway 16 having an inlet connecting end 16a which is connectible to a discrete source of beverage syrup (not shown). Passageway 16 and outlet port 15 each have a discrete normally closed valve 20, 22 respectively, that is openable for dispensing of beverage. The water valve 20 is usually also operable by itself, for dispensing pure carbonated water without syrup. The syrup passageway 16 ultimately leads to a dispensing nozzle 24 as does a water outlet port 26 extending from the water valve 20 to the nozzle 24. A specific dispensing nozzle 24 may be the one shown in U.S. Pat. No. 4,549,675, may be the one shown in U.S. Pat. No. 4,509,690, or may be of other common or yet to be developed types. The nozzle 24 usually initially mixes the carbonated water and syrup together prior to the beverage falling into any appropriate receptacle, such as a cup or pitcher (not shown). In-between the water inlet port 14 and the water valve 20 is a cylindrical water flow control housing 28 having an elongate cylindrical inner surface 30 defining an inner pocket of the housing 28. The water inlet portion 14 extends into the bottom of the housing 28 and into fluid communication with the inner surface 30. Outlet feed port 15 intersects through the cylindrical inner surface 30 and into the housing 28. The feed port 15 extends directly from the housing 28 to the normally closed water valve 20.
A fixed water flow control shaped like a piston plug 34 is inserted, fixed, retained, in and sealed to the housing 28. Piston 34 is retained in housing 28 by retaining means 35. The combined structure of the piston 34 and cylindrical inner surface 30 is the important structural feature of this invention and is important structure in the practice of the method of the present invention.
The piston 34 has precisely sized outer diametric surface 36 loosely slip-fitted within the cylindrical inner surface 30. A preferred specific diameter of the diametric piston surface 36 is 0.823±0.001 inches (20.9±0.025 mm) and a preferred specific diameter of the cylindrical inner surface 30 is 0.842±0.002 inches 21.4±0.05 mm). The annular clearance between the surfaces 30, 36 is in the range of 0.005-0.015 inches (0.125-0.375 mm) and a specific preferred clearance is 0.010±0.002 inches (0.25±0.05 mm). A toroidal carbonated water decompression chamber 38 is formed between the surfaces 30, 36 and O-rings 39, and is the annular clearance just specifically identified. A carbonated water flow port 40 extends upward from the bottom of the piston 34 and fluidly branches off into a single outlet 42 which interacts with and through the piston diametric surface 36 into the chamber 38.
A preferred diameter of the flow port 40 and its outlet 42 is 0.125 inch (3.18 mm) diameter. A radial index indicator 44 is provided on the outer end of the piston 36. The indicator 44 has a fixed radial location with respect to the flow port outlet 42 for selective and predetermined radial orientation of the single outlet 42 within the housing 28. The preferred orientation of the outlet 42 is directly opposite to the feed port 15.
Opposite orientation provides a parallel flow path in the decompression chamber 38. The flow path extends from the outlet 42 around both sides of the piston 34 to the feed port 15. In the bottom of the piston 34 and at the inlet of the flow port 40 is a fixed rate elastomeric volumetric flow control washer 46. The washer 46 is held captive in the piston 34 by a snap fit retainer cap 48. The flow washer 46 is preferably non-adjustable and is always upstream of the decompression chamber 38. The decompression chamber 38 is of a precise predetermined size and is not adjustable.
The cross sectional areas of the various section of the water passageway is quite critical. The water inlet port 14 has a relatively quite large cross sectional area. The water 15, and water valve 20 and water outlet port 26 have a minimum diameter of 0.160 inches (4.06 mm) and therefore a minimum cross sectional area of 0.020 square inches. The inlet port 14 is preferably larger than the feed port 15. The flow port 40 has a cross sectional area of 0.012 square inches and is smaller in cross section through the feed port 15. The decompression chamber 38 has a preferred height of 0.265 inches (6.7 mm) and has a singular cross sectional flow pathway area of 0.0065 square inches and a parallel double flow pathway area of 0.013 square inches. The cross sectional area of the decompression chamber is always smaller than the smallest cross sectional area in the feed port 15, open water valve 20, outlet port 26 or nozzle 24. The flow port 40 has a larger cross-sectional area than the decompression chamber 38 but smaller than any cross sectional area downstream of the decompression chamber 38.
In the use of the dispensing head 10 and the beverage dispensing system as described, and in the practice of the method of the present invention, carbonated water under a predetermined propellant pressure is provided at the inlet connecting end 14a. When the water valve 20 is normally closed, full propellant pressure is hydrostatically applied all the way through the water passageway ports 14 and 15 to the water valve 20. During dispensing the water valve 20 is solely opened to dispense only carbonated water, and both valves 20, 22 are opened to dispense a complete soft drink. Syrup flows through the syrup passageway 16 and into and out of the nozzle 24 in conventional fashion.
The carbonated water however, flows firstly through the flow washer 46 wherein the volumetric flow rate is controlled. Specific preferred predetermined carbonated water flow rates are 1.25 oz./sec. regular flow and 2.50 oz./sec. high flow. The carbonated water leaves the flow washer 46 and enters and goes through the reduced cross section flow port 40 and through the piston 34. An initial partial pressure reduction is made in the flow port 40. The carbonated water then exits out of the flow port 40 and into the highly restrictive decompression chamber 38. The flow of carbonated water through the chamber 38 is laminar & non-turbulent, and provides the greatest pressure drop experienced by the carbonated water, specifically the carbonated water is depressurized down to just above atmospheric. The carbonated water then is fed out the feed port 15, and through the valve 20 and the outlet feed port 15, and through the valve 20 and the outlet port 26 to the nozzle 24 and then into the receptacle. The pressure drop downstream of the decompression chamber 38 is negligible.
It has been found, in actual testing, that whereas the original dispensing valve us U.S. Pat. No. 4,549,675 with the high efficiency nozzle of U.S. Pat. No. 4,509,690, would put a beverage into a cup with 3.6 volumes of carbonation. The improved dispenser head 10 and the method herein described provide a dispensed fountain beverage into a cup which consistently measures to have 4.2 volumes of carbonation with less foaming of the beverage during dispensing. The dispensed carbonated water per se without syrup likewise has a higher carbonation in the cup.
Although other advantages may be found and realized and various modifications may be suggested by those versed in the art, it should be understood that I wish to embody within the scope of the patent warranted hereon, all such embodiments as reasonable and properly come within the scope of my contribution to the art.
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A beverage dispensing head and a method of dispensing that provides increased carbonation in a dispensed fountain beverage. The dispensing head has a discrete carbonated water decompression chamber in-between an upstream volumetric flow control body and a downstream normally closed valve. The method includes the steps of propelling carbonated water through a flow control body and then decompressing the carbonated water before it reaches the normally closed valve.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention refers to a method and an apparatus for removing noise spikes from an electrical signal having an AC component.
2. Description of the Related Art
Electrical signals can comprise noise spikes causing disturbance during processing or use of the electrical signal. One example are noise spikes introduced by car engine's electronic interference to radio amplitude modulated (AM) signals. Such noise spikes disturb the output signal of loudspeakers cooperating with an AM car radio.
In many applications it is desired to remove noise spikes.
U.S. Pat. No. 4,965,800 discloses a digital signal fault detector using a low voltage threshold and a high voltage threshold for discriminating binary low states and binary high states, respectively, and comprising a spike detector for detecting signal faults caused by spikes. It is assumed that typical non-spike pulses have a pulse time which is longer than a spike time. The spike detector comprises a low voltage threshold and a high voltage threshold for identifying the state of the input signal as low or high, a means for measuring the continuous duration in the low or the high state and for comparing it with the predetermined spike time, and a means for communicating the occurrence of a spike when the continuous duration of the signal in the low state or the high state is less than the spike time. The spike detector disclosed in U.S. Pat. No. 4,965,800 is not able to react on changes as regards the strength of the input signal. As a consequence, a weak input signal might be discriminated incorrectly and spikes might not be detected.
Such problems might be less serious in case of processing digital input signals which are to be discriminated as to having the low or the high state, only. The problem is, however, much more serious in case of amplitude modulated analog signals, e.g., AM radio signals.
SUMMARY OF THE INVENTION
Embodiments of the present invention aim at removing noise spikes from signals having variable strength, in particular from amplitude modulated analog signals.
Under a first aspect, the invention provides a method for determining the actual rms value of the input signal, low pass filtering the input signal, producing a variable offset, said variable offset being a function of the actual rms value, forming a variable threshold by superimposing the variable offset to the low pass filtered signal, comparing the input signal to the variable threshold, creating a spike detection signal when the input signal passes the variable threshold, and blanking the input signal during the occurrence of the spike detection signal.
By using a variable offset which is dependent on the actual rms value of the input signal and by forming a variable threshold obtained by superimposing the variable offset to a low pass filtered version of the input signal, the threshold and, in turn, the spike detection performance is adapted to a varying strength of the input signal. The threshold approximately follows the amplitude of the input signal with a certain distance therefrom, that does not follow spikes introduced to the input signal because of superimposing the variable offset not to the input signal itself but to the low pass filtered input signal. As a result, different from using a non-variable threshold, spikes can be safely detected irrespective of whether the actual strength of the input signal is high or low.
The removal of a detected noise spike is obtained by blanking the input signal during the occurrence of the spike detection signal.
Under a second aspect, the invention provides an apparatus for removing noise spikes from an electrical input signal having an AC component, comprising means designed for determining the actual rms value of the input signal, a low pass filter low pass filtering the input signal, an offset generator designed for producing a variable offset as a function of the actual rms value, superimposition means designed for forming a variable threshold by superimposing the variable offset to the low pass filtered signal, comparator means adapted for comparing the input signal to the variable threshold and for creating a spike detection signal when the input signal passes the variable threshold, and blanking means designed for blanking the input signal during the occurrence of the spike detection signal.
In an embodiment of the invention, the blanking time is made dependant on the actual rms, i.e. the actual strength of the input signal. Assuming that a spike has a shape which is independent from the shape and the strength of the input signal, the time period during which a detected spike is above (in case of positively directed spikes) or below (in case of negatively directed spikes) the input signal is larger for a weak input signal and is smaller for a strong input signal. This effect can be taken into consideration by making the blanking time dependant on the actual strength of the input signal.
In an embodiment of the invention, the blanked part of the input signal is replaced with an interpolated replacement signal, wherein the interpolated signal is obtained by taking the last input signal value before the blanking time and the first input signal value after the blanking time and by forming a ramp connecting these two input signal values.
If positive spikes are to be expected only, merely a high variable threshold is formed by adding to the input signal a positive variable offset and creating the spike detection signal when the input signal is above the variable high threshold. If negative spikes are to be expected only, merely a low variable threshold is formed by subtracting from the input signal a negative variable offset and creating the spike detection signal when the input signal is below the variable low threshold. If positive and negative spikes are to be expected, a high variable threshold as well as a low variable threshold are formed and the spike detection signal is created when the input signal is above the high variable threshold or below the low variable threshold.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)
Advantages and features of the present invention will become more fully apparent from the following description of embodiments in conjunction with the accompanying drawings.
FIG. 1 shows a weak input signal with an interfering spike;
FIG. 2 shows a strong input signal with the same interfering spike;
FIG. 3 shows a first embodiment of a spike detection and spike cancellation circuitry of the present invention;
FIG. 4 shows an amplitude modulated signal and its envelope, high and low variable thresholds, a positive spike, and a negative spike;
FIG. 5 shows a second embodiment of a spike detection and spike cancellation circuitry of the present invention;
FIG. 6 shows a graph depicting the dependencies of the variable offsets and the blanking time on rms and Vp;
FIG. 7 shows a third embodiment of a spike detection and spike cancellation circuitry of the invention;
FIG. 8 shows
( a ) an AM signal with spikes,
( b ) trigger pulses fox starting blanking tunes, and
( c ) AM signals after removal of spikes and interpolation;
FIG. 9 shows the same signals as FIG. 8, however with higher resolution as to the time axis;
FIG. 10 shows signals measured at circuit points indicated in FIG. 7; and
FIG. 11 shows the result of noise measurements.
FIG. 12 is a block diagram of an embodiment of the invention employing a digital divider.
DETAILED DESCRIPTION OF THE INVENTION
In an embodiment of the invention shown in FIG. 12, the input signal is digitized by an analog/digital converter 200 into a sequence of pulses which is divided by a divider 202 into blocks each having a predetermined number of pulses, e.g., 128 pulses. In this embodiment, the actual rms of each block is calculated by an RMS calculator 204 by means of the following formula: rms = ∑ l = 1 n x i 2 n ( 1 )
As it is difficult and time consuming for usual microprocessors to calculate square roots, processing according to the following formula is carried out: rms ~ ∑ l = 1 n x i 2 n ( 2 )
In an embodiment of the invention, the sequence of pulses is transmitted through a digital delay line having taps for tapping pulses traveling through the delay line. Upon occurrence of a spike detection signal, the pulses occurring before the beginning and after the end of the blanking time are tapped from the delay line and the blanked part of the input signal pulses is replaced with pulses obtained by means of an interpolation between the pulses occurring before the beginning and after the end of the blanking time.
The present invention can be used for removing spikes from a demodulated signal obtained by amplitude demodulating an amplitude modulated signal, in particular for removing spikes from an AM audio signal, e.g. of an AM radio signal, where spikes are introduced by the electronic of a car engine, for example. In an embodiment of the invention for removing noise spikes from a radio AM signal, the AM-IF signal (intermediate frequency signal of the AM radio signal) is supplied to a spike detector path and the demodulated AM audio signal is supplied to a spike cancellation path of the invention. In the spike detection path, an envelope signal is generated from the envelope of the amplitude modulated signal, the actual rms value and a local peak value of the envelope signal are calculated, the envelope signal is low pass filtered, the variable offset is produced as a function of the actual rms value and the local peak value, a variable threshold is formed by superimposing the variable offset to the low pass filtered envelope signal, the envelope signal is compared to the variable threshold, and a spike detection signal is created when the envelope signal passes the variable threshold. In the spike cancellation path, the demodulated signal is blanked during the occurrence of a spike detection signal and the blanked part of the demodulated signal is replaced with an interpolated signal.
Because the variable offset is a function of the actual rms value and the actual peak value of the envelope signal, and because the variable threshold is formed by superimposing the suchlike obtained variable offset to the low pass filtered envelope signal, the threshold is made dependent on the signal strength and the signal amplitude, on the one hand, and follows the envelope of the amplitude modulated signal with a certain distance without following peaks, on the other hand.
In an embodiment of the invention, the blanking time is made dependent on the local peak value. This takes into consideration that the peak value of a spike is independent from the peak value of the modulated signal so that the time the envelope signal is masked by a spike is larger for low peak values of the envelope, and is smaller for high peak values of the envelope.
There are further applications for the invention besides the above-mentioned removal of the spikes from an AM radio signal:
Scratches or dust particles on long play vinyl discs cause spikes in the electrical audio signal obtained from the pick-up of a long play disc player, to be heard as clicks. Such spikes can be removed by means of the present invention.
Sensors for controlling hard disc drives generate output signals which can be disturbed by noise such as spikes. Such spikes can also be removed by use of the present invention because the normal spike frequency range is different from the frequency range of the sensor head signal.
FIGS. 1 and 2 shows an electrical signal s having an AC component and being disturbed by an interfering spike, the electrical signal s being weak in FIG. 1 and strong in FIG. 2 . The time period ti during which the spike exceeds the electrical signal s is larger for the weak signal in FIG. 1 and smaller for the strong signal in FIG. 2 .
FIG. 3 shows a first embodiment of the present invention comprising a spike detection path (upper path) and a spike cancellation path (lower path).
An input IN common to the spike detection path and the spike cancellation path receives the electrical signal s.
The spike detection path comprises an rms calculator 11 , an offset generator 13 , a low pass filter 15 , a summing circuit 17 and a comparator 19 . The comparator 19 comprises a signal input Is and a threshold input Ith. The rms calculator 11 passes the input signal s to an input of low pass filter 15 and to the signal input Is of the comparator 19 . The rms calculator 11 calculates from the electrical signal s a actual rms value which is supplied to an input of the offset generator 13 generating a variable offset which is dependent on the actual rms value. The low pass filter 15 has such a filter characteristic that the AC component of the electrical signal s is substantially not changed whereas spikes are substantially suppressed. The low pass filtered signal from low pass filter 15 and the variable offset from offset generator 13 are supplied to summing circuit 17 where the low pass filtered signal and the variable offset are accumulated to a variable threshold supplied to the threshold input Ith of the comparator 19 . Comparator 19 compares the unchanged signal s to the variable threshold and outputs a spike detection signal when the electrical signal s is above the variable threshold.
The spike cancellation path comprises a delay line 21 , a linear interpolator 23 , a switch 25 , and a low pass filter 27 . The delay line 21 receives the electrical signal s and passes the signal s to a first input SWi 1 of the switch 25 . An output SWo of the switch 25 is connected to an input of the low pass filter 27 , the output of which forms the output OUT of the cancellation path.
The delay line 21 has tabs (three in the embodiment shown in FIG. 3) for supplying to the interpolator 23 amplitude values of the signal s occurring at different times. The linear interpolator 23 further receives the actual rms value from the rms calculator 11 and the spike detection signal spds from the comparator 19 . An output of the linear interpolator 23 is connected to a second input SWi 2 of the switch 25 . The switching states of switch 25 are controlled by the spike detection signal spds from the output of the comparator 19 and by an output signal bte from the interpolator 23 , signaling the end of the blanking time.
The embodiment of FIG. 3 is designed for detection and cancellation of positive spikes only. It can easily be modified for detection and cancellation of negative spikes or for detection and cancellation of positive as well as negative spikes. If to be modified for the detection and cancellation of negative spikes, the only change to be made with respect to FIG. 3 is that the offset from offset generator 13 is not added to but subtracted from the low pass filtered signal from low pass filter 15 and that the signal input Is and the threshold Ith of the comparator 19 are changed.
If the embodiment of FIG. 3 is to be modified for detection and cancellation of positive and negative spikes, a second offset generator 13 , a second low pass filter 15 , a second summing circuit 17 , a second comparator 19 and an OR gate would have to be added, as shown and explained below in context with the embodiment shown in FIG. 5 .
The operation of the embodiment of FIG. 3 is now explained with reference to FIGS. 1 and 2. For simplification, it is assumed that the electrical signal s after being low pass filtered by means of low pass filter 15 has the same form which the electrical signal s would have if there were no spikes.
The rms calculator 11 calculates actual rms values of rms (t) from the signal course of the electrical signal s during actual time periods of a predetermined time duration. The offset generator 13 generates high offset values for high actual rms values and generates low offset values for low rms values. For that reason, the distance of the variable threshold th from the electrical signal s is shown to be smaller in FIG. 1 and is shown to be larger in FIG. 2 .
When no spike is detected, the switch 25 is in the state in which its output SWo is connected to its input Swi 1 so that the electrical signal, after passing the delay line 21 , is supplied via the switch 25 to the low pass filter 27 and then to the output OUT.
When the input signal s comprising the spike goes above the variable threshold th and the comparator 19 outputs a spike detection signal spds, the switch 25 is switched into the state in which SWo is connected to SWi 2 so that the output signal of the linear interpolator 23 is supplied to the low pass filter 27 and then to the output OUT.
The linear interpolator 23 has several functions. First, the interpolator 23 generates a blanking time tb as a function of the actual rms value received from the rms calculator 11 . The blanking time tb generated by the interpolator 23 is larger for a weak electrical signal s, i.e., for smaller current actual rms, and is smaller for a strong electrical signal s, i.e., for higher actual rms values because the time during which the spike exceeds the signal s is the larger the weaker the signal s is. Second, the interpolator 23 controls the switch 25 to fall back to the state in which SWo is connected to SWi 1 , at the end of the blanking time tb. Third, the interpolator 23 selects from the delay line 21 the actual amplitude value of the signal s related to the point of time just before the beginning of the blanking time tb, and the actual amplitude value of the signal s related to the point of time just after the end of the blanking time tb. On the basis of these two selected amplitude values, the interpolator 23 generates an interpolated section of the signal and replaces the detected spike with the interpolation signal section resulting in a cancellation of the spike from the electrical signal s.
Use of the invention for cancellation of noise spikes from AM radio signals is now explained with reference to FIGS. 4 to 11 .
FIG. 4 depicts an IF (intermediate frequency) of an AM radio signal, an envelope e of the IF AM signal, a low threshold th-lo, a high threshold th-hi, an rms value, a positive spike, and a negative spike. For simplification, it is assumed in FIG. 4 that rms does not change during the time shown in FIG. 4 and that, therefore, the distances of th-lo and th-hi from e are constant during the time shown in FIG. 4 .
An embodiment of the invention for spike detection and spike cancellation in connection with an AM radio signal is shown in FIG. 5 . It is assumed that positive spikes as well as negative spikes can occur so that a positive variable threshold as well as a negative variable threshold are generated, as shown in FIG. 4 .
In the embodiment of FIG. 5, the spike detection path receives the AM-IF signal whereas the spike cancellation path receives the demodulated AM audio signal. The AM-IF signal is supplied to an envelope follower 31 which produces an envelope signal e of the positive envelope of AM-IF.
Elements in FIG. 5 having the same function as elements in FIG. 3 have the same reference numerals as in FIG. 3 . The spike detection path of FIG. 5 has elements related to the detection of positive spikes, the reference signs of which comprise a letter h (like high), and elements related to the detection of negative spikes, the reference signs of which comprise a letter l (like low). For instance, the offset generators for generating a variable high offset and for generating a variable low offset have the reference signs 13 h and 13 l, respectively. The spike cancellation path of FIG. 5 is identical to that of FIG. 3 .
Summing circuit 17 h of FIG. 5 adds the variable offset from offset generator 13 h to the low pass filtered signal from low pass filter 15 h, as in FIG. 3, whereas summing circuit 17 l subtracts the low variable offset from offset generator 13 l from the low pass filtered signal from low pass filter 15 l. The circuitry in FIG. 5 comprises an OR gate 29 performing an OR function with respect to the outputs of both comparators 19 h and 19 l.
The envelope following signal e is passed through the rms calculator 11 and through a Vp calculator 33 before it is supplied to the low pass filters 15 h and 15 l and to the signal inputs Ish and Isl of the comparators 19 h and 19 l, respectively.
The Vp calculator 33 calculates the local peak value Vp of the envelope following signal e and supplies the actual Vp value to second inputs of the offset generators 13 h and 13 l and to a further input of the linear interpolator 23 . Thus, the variable high offset and the variable low offset and, as a consequence, the high threshold and the low threshold, and further the blanking time generated by the interpolator 23 , are made dependent not only on the actual rms value but also on the actual Vp value of the envelope following signal e.
The passing of one of the thresholds th-hi and th-lo by the envelope following signal e causes a pulse triggering of the switch 25 whose lasting (blanking time t-out) depends on the actual rms and Vp values as shown in FIG. 6 . According to FIG. 6, for rms values above a predetermined threshold rms th, there 1 s generated a high offset offs-hi (2), a low offset offs-lo (2) and a blanking time t-out (2). For rms values below rmsth and Vp values being above a Vp threshold Vpth, there are generated a high offset offs-hi (1), a low offset offs-lo (1) and a blanking time t-out (1). For rms values below rms th and Vp values below Vp th, there are generated a high offset offs-hi (0), a low offset offs-lo (0) and a blanking time t-out (0).
In a modification of the embodiment of FIG. 5, the low pass filters 15 h, 15 l are located between the summing circuits 17 h, 17 l and the comparators 19 h, 19 l.
In a modified embodiment, the thresholds rmsth and Vpth are not fixed but are variable depending on the current rms value and/or the current Vp value.
The effect of this modeling is the following: for high values of the field-strength (rms high) values (2) will be chosen for offset thresholds and blanking time. For low values of the field-strength (rms low), values (1) or (0) will be chosen according to the peak level Vp of the AM-IF signal which is related to the modulation depth. This makes the AM noise blanker routine adapting on the quality of the AM signal received. The idea is to have short blanking time and high offsets for high values of the field-strength, and longer blanking time and lower offsets for low values of the field-strength.
There are the following relationships:
offs-hi(2)>offs-hi(1)>offs-hi(0) (3)
offs-lo(2)>offs-lo(1)>offs-lo(0)
t-out(0)>t-out(1)>t-out(2) (5)
In a modified embodiment, fixed thresholds rmsth and Vpth are replaced with variable thresholds depending on the actual rms value and/or the actual value of Vp.
A trigger pulse occurring upon the detection of a spike causes the switching of the AM audio path into the blanking and interpolating state. At the end of the blanking time and, in turn, the interpolation, the AM audio path is switched back to the non-blanking state.
In a preferred embodiment shown in FIG. 7, the signal processing in the spike detection path and the pike cancellation path is made on a digital basis. This embodiment comprises all of the elements of FIG. 5 and additional elements required for the digital signal processing. Elements in FIG. 7 corresponding to elements in FIG. 5 have the same reference signs as in FIG. 5 .
As shown in FIG. 7, the envelope follower 31 comprises a rectifier diode so that the positive envelope following signal is generated only. The envelope following signal e is supplied to a first analog/digital converter (ADC 1 ) 34 digitizing the envelope following signal e into a sequence of pulses. The pulses from the ADC 1 are filtered by a low-pass filter 35 in order to avoid any aliasing. The low-pass filtered signal is supplied to a digital delay line (DLY 3 ) 37 having the function of elements 11 and 33 of FIG. 5 . The samples contained in the delay line 37 are used to calculate two values which are proportional to the actual rms value rms (t) and the local peak level Vp (t) of the AM-IF signal. Calculation of rms and Vp values by means of a delay line is known to the expert and is not needed to be explained in more detail here.
These two values are used to modify the variable high offset value offs-hi and the variable low offset value offs-lo used to generate the variable high threshold th-hi and the variable low threshold th-lo moving around the envelope following signal e.
In the embodiment of FIG. 7, a single offset generator 13 is used and the output thereof is supplied to both summing circuits 17 h and 17 l. The low pass filters 15 h and 15 l are arranged between the respective summing circuit 17 h, 17 l and the respective comparator 19 h, 19 l, in modification to the embodiment of FIG. 5 where the low pass filters 15 h and 15 l are arranged upstream the summing circuit 17 h and 17 l, respectively.
Further, the AM-IF path or spike detection path of FIG. 7 comprises a high pass filter (HP) 38 connected to the output of the first delay line 37 , and an automatic gain control (AGC) 40 controlling the signal from the high pass filter 38 in response to the actual rms value.
In the AM audio path or spike cancellation path, the samples coming from a second analog/digital converter (ADC 0 ) 39 are delayed by means of a second delay line (DLY 2 ) 41 and by a third delay line (DLY 3 ) 43 . The delay line 43 is designed to store a number of samples which correspond to the maximum blanking time to be expected. As already explained above in context with FIG. 5, the delay line 43 supplies to the linear interpolator 23 the last “good” sample before the blanking time and the first “good” sample after the blanking time so that the linear interpolator 23 can interpolate during the blanking time tb a sequence of samples which form a ramp between the last good sample before the blanking time and the first good sample after the blanking time.
When the trigger pulse or spike detection pulse is active, a linear interpolation between the last “good” sample before the trigger pulse and the first “good” sample after the blanking time is performed. Following the switch 25 is a steep low-pass filter 27 (called head filter) which removes all the spurious “clicks” introduced by the switching. The resulting pulse stream is passed to a digital signal processor DSPO which performs the audio processing.
FIGS. 8 and 9 show signals occurring at different locations of the AM noise blanker circuit of FIG. 7, with FIG. 9 showing the signals with a higher resolution than FIG. 8 . FIGS. 8 ( a ) and 9 ( a ) show the AM-IF signal having spikes. FIGS. 8 ( b ) and 9 ( b ) show trigger pulses at the output of OR gate 21 . FIGS. 8 ( c ) and 9 ( c ) show the AM audio signal after spike cancellation and interpolation during the blanking times.
FIG. 10 shows signals at circuit points P 1 to P 4 indicated in FIG. 7, with the signal at P 1 being the original audio AM signal, the signal at P 2 being the blanked audio AM signal, the signal at P 4 being the AM-IF envelope follower signal e, and the signal at P 3 being the AM-IF envelope follower signal after the analog-to-digital conversion by means of ADC 1 .
The ADC 1 converter 34 , due to its own structure, makes causes a phase inversion and a delay (approximately 1 ms), therefore the original positive spikes of the signal at P 4 are inverted at P 3 , and delayed of 1 ms.
FIG. 11 shows noise measurements. The x-line shows a noisy signal without noise blanking, the o-line shows a noisy signal with noise blanking, and the continuous line (the lowest line) shows a clean signal, i.e., a signal without noise. It can be seen from FIG. 11 that an implementation of the present invention such as shown in FIG. 7 results in a signal which is almost as free of noise as the clean signal at a lower range of the field-strength which is the range where AM signals are particularly sensitive to noise and noise spikes.
In an implementation of the embodiment of FIG. 7, the low pass filter 35 has a cut-off frequency of 20 KHz, the low-pass filter part of the envelope follower 31 has a cut-off frequency of 28 KHz, and the analog/digital converters 33 and 39 have a sampling frequency of 48.5 KHz. The delay line 41 is for compensating any difference in the behavior of the analog/digital converters 33 and 39 .
All of the above U.S. patents, U.S. patent application publications, U.S. patent applications, foreign patents, foreign patent applications and non-patent publications referred to in this specification and/or listed in the Application Data Sheet, are incorporated herein by reference, in their entirety.
From the foregoing it will be appreciated that, although specific embodiments of the invention have been described herein for purposes of illustration, various modifications may be made without deviating from the spirit and scope of the invention. Accordingly, the invention is not limited except as by the appended claims.
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The invention provides a method for removing noise spikes from an electrical input signal having an AC component, comprising the steps of determining the actual rms value of the input signal, low pass filtering the input signal, producing a variable offset, said variable offset being a function of the actual rms value, forming a variable threshold by superimposing the variable offset to the low pass filtered signal, comparing the input signal to the variable threshold, creating a spike detection signal when the input signal passes the variable threshold, and blanking the input signal during the occurrence of the spike detection signal.
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CROSS REFERENCE TO RELATED APPLICATIONS
This application is a division of copending application Ser. No. 08/993,684, filed Dec. 18, 1997.
BACKGROUND OF THE INVENTION
The present invention is directed to bicycle accessories and, more particularly, to an antitheft control device for a bicycle.
Bicycles, particularly recreational bicycles referred to as city cruisers, are inexpensive and are easy to ride, and are thus widely used to commute to work or school. This type of recreational bicycle is sometimes equipped with an internal gear shifter to ride at high speeds over flat terrain or to ride uphill with minimal exertion. Such internal gear shifters commonly use planet reduction mechanisms, which are compactly housed in the wheel hub.
Unfortunately, such recreational bicycles are often stolen from bike stands or the like in front of train stations, not out of any particular ill will, but as a kind of "quick borrow." Bicycles which are obviously equipped with internal gear shifters are a particular target of such thefts. To prevent this type of theft, bicycle locks such as box-shaped locks and horseshoe-shaped locks are attached to the front or back fork to lock the wheel. However, the simple structure of bicycle locks makes them easy to unlock and remove. Two bicycle locks are thus sometimes attached to the front and back forks. For example, a box-shaped lock is attached to the front fork, and a horseshoe-shaped lock or chain lock is attached to the back fork. When two bicycle locks are used, there is less of a probability of theft because it is more trouble for a potential thief to unlock and take off two locks than just one. On the other hand, it is a nuisance for the owner to lock and unlock them. Similarly, when a rider is in a hurry, it is a burden to lock two locks. And even when two locks are used, bicycles can still be pedaled away and stolen by unlocking and taking off the locks.
SUMMARY OF THE INVENTION
The present invention is directed to an antitheft device for a bicycle wherein the antitheft device can be easily activated or deactivated by the owner while also being very difficult for a thief to defeat. In one embodiment of the present invention, a bicycle antitheft device includes an antitheft mechanism switchable between an antitheft state and a release state, wherein the antitheft mechanism includes a first member that moves relative to a second member to move the bicycle forward and backward. A movement controlling mechanism hinders the first member from moving relative to the second member when the antitheft mechanism is in the antitheft state, and a selection mechanism is provided for selecting one of the antitheft state and the release state. Alternatively, the antitheft mechanism may include a sound generator for generating a sound when the first member moves relative to the second member and the antitheft mechanism is in the antitheft state. Furthermore, if desired, the movement controlling mechanism and the sound generator may be combined into a single antitheft mechanism. The movement controlling mechanism and/or sound generator may be installed inside of an internal transmission such as a hub or crank transmission, or they could be installed inside a handlebar control for the transmission.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side view of a bicycle in which a particular embodiment of an antitheft device according to the present invention may be employed;
FIG. 2 is an oblique view of a particular embodiment of a handlebar control mechanism used with an antitheft device according to the present invention;
FIG. 3 is a block diagram of a particular embodiment of an electronic control mechanism that may be used with the antitheft control device according to the present invention;
FIG. 4 is a partial cross sectional view of a bicycle hub transmission that incorporates a particular embodiment of an antitheft device according to the present invention;
FIG. 5 is a diagram showing the relationship between a first sun gear and drive pawls when the hub transmission shown in FIG. 4 is in a fourth gear;
FIG. 6 is a diagram showing the relationship between lock pawls, drive pawls and a third sun gear when the hub transmission shown in FIG. 4 is in the fourth gear;
FIG. 7 is a diagram showing the relationship between a first sun gear and drive pawls when the hub transmission shown in FIG. 4 is in a locked state;
FIG. 8 is a diagram showing the relationship between lock pawls, drive pawls and a third sun gear when the hub transmission shown in FIG. 4 is in the locked state;
FIG. 9 is a detailed cross-sectional view of a particular embodiment of a sound generating mechanism according to the present invention when the bicycle is in motion;
FIG. 10 is a detailed cross-sectional view of the antitheft device shown in FIG. 9 when the bicycle is in a locked state;
FIGS. 11(a)-11(c) are views showing the operation of the antitheft device of FIG. 9;
FIG. 12 is a flow chart of a particular embodiment of a main routine for shift processing in a shift control device that incorporates an antitheft device according to the present invention;
FIG. 13 is a flow chart showing overall password processing in a shift control device that incorporates an antitheft device according to the present invention;
FIG. 14 is a flow chart showing password registration processing in a shift control device that incorporates an antitheft device according to the present invention;
FIG. 15 is a flow chart showing automatic shift processing in a shift control device that incorporates an antitheft device according to the present invention;
FIG. 16 is a flow chart showing manual shift processing in a shift control device that incorporates an antitheft device according to the present invention;
FIG. 17 is a partial cross sectional view of a bicycle hub transmission that incorporates an alternative embodiment of an antitheft device according to the present invention;
FIG. 18 is a detailed cross-sectional view of a particular embodiment of the antitheft device shown in FIG. 17 when the bicycle is in motion;
FIG. 19 is a detailed cross-sectional view of the antitheft devce shown in FIG. 17 when the bicycle is in a locked state;
FIGS. 20(a)-20(b) are views showing the operation of the antitheft device of FIG. 17;
FIG. 21 is a front view of a lock ring used in the antitheft device of FIG. 17;
FIG. 22 is an oblique view of an alternative embodiment of a handlebar control mechanism used with an antitheft device according to the present invention;
FIGS. 23(a)-23(c) are cross sectional views of a particular embodiment of a locking mechanism used with the handlebar control mechanism shown in FIG. 22;
FIG. 24 is a partial cross sectional view of a bicycle hub transmission that incorporates another alternative embodiment of an antitheft device according to the present invention;
FIG. 25 is a partial cross sectional view of a front hub that incorporates an embodiment of an antitheft device according to the present invention;
FIG. 26 is a partial cross sectional view of a crank transmission that incorporates an embodiment of an antitheft device according to the present invention;
FIGS. 27(a)-27(c) are views showing the operation of the antitheft mechanism of FIG. 26;
FIG. 28 is an oblique view of another alternative embodiment of a handlebar control mechanism used with an antitheft device according to the present invention;
FIG. 29 is an oblique exploded view of a particular embodiment of a lock component used in the handlebar control mechanism shown in FIG. 28; and
FIGS. 30(a)-30(b) are views showing the operation of the antitheft mechanism of FIG. 29.
DETAILED DESCRIPTION OF THE EMBODIMENTS
FIG. 1 is a side view of a bicycle in which a particular embodiment of an antitheft device according to the present invention may be employed. The bicycle includes a frame 1 with a double-loop type of frame unit 2 and a front fork 3; a handle component 4; a drive component 5; a front wheel 6; a rear wheel 7 in which a four-speed internal shifting hub 10 is mounted; front and rear brake devices 8 (only the front brake device is shown in figure); and a shift control element 9 for conveniently operating the internal shifting hub 10. The drive component 5 has a gear crank 18 that is provided to the lower portion (bottom bracket portion) of the frame body 2, a chain 19 that is wrapped around the gear crank 18, and the internal gear hub 10.
Various components, including a saddle 11 and a handle component 4, are attached to the frame 1. A bicycle speed sensor 12 furnished with a bicycle speed sensing lead switch is mounted on the front fork 3. This bicycle speed sensor 12 outputs a bicycle speed signal by detecting a magnet 13 mounted on the front wheel 6. The handle component 4 has a handle stem 14 that is fixed to the upper portion of the front fork 3 and a handlebar 15 that is fixed to the handle stem 14. Brake levers 16 and grips 17 which constitute part of the brake devices 8 are mounted at either end of the handlebar 15. A shift control element 9 is mounted on the right-side brake lever 16.
As shown in FIG. 2, the shift control element 9 has a control panel 20 formed integrally with the right-side (front-wheel) brake lever 16, two control buttons 21 and 22 disposed next to each other to the left and right on the lower portion of the control panel 20, a control dial 23 disposed above the control buttons 21 and 22, and a liquid-crystal display component 24 disposed to the left of the control dial 23. The current riding speed is displayed on the liquid-crystal display component 24, as is the speed step selected at the time of the shift.
The control buttons 21 and 22 are triangular push buttons. The control button 21 on the left side is used to perform shifts to a higher speed step, while the control button 22 on the right side is used to perform shifts to a lower speed step. The control dial 23 is used to switch among two shifting modes and a parking mode (P), and it has three stationary positions: P,A, and M. Here, the shift mode comprises an automatic shift (A) mode and a manual shift (M) mode. The automatic shift mode is for automatically shifting the internal shifting hub 10 by means of a bicycle speed signal from the bicycle speed sensor 12, and the manual shift mode is for shifting the internal shifting hub 10 through the operation of the control buttons 21 and 22. The parking mode is for locking the internal shifting hub 10 and controlling the rotation of the rear wheel 7.
A shift control component 25 (FIG. 3) that is used to control shifting is housed inside the control panel 20. The shift control component 25 comprises a microcomputer consisting of a CPU, a RAM, a ROM, and an I/O interface. As shown in FIG. 3, the shift control component 25 is connected to the bicycle speed sensor 12, an actuation position sensor 26 composed of a potentiometer (for example, a potentiometer that senses the actuation position of the internal shifting hub 10), the control dial 23, and the control buttons 21 and 22. The shift control component 25 is also connected to a power supply 27 (consisting of a battery), a motor driver 28, the liquid-crystal display component 24, a memory component 30, and another input/output component. A shift motor 29 is connected to the motor driver 28. Various types of data, such as the password (PW) discussed below or the tire diameter, are stored in the memory component 30. The relation between the speed step and the speed during the automatic shift mode is also stored. The shift control component 25 controls the motor 29 according to the various modes, and also controls the display of the liquid-crystal display component 24.
As shown in FIG. 4, the internal gear hub 10 primarily has a hub axle 41 that is fixed to the rear portion of the bicycle frame 1, a driver 42 that is located around the outer periphery at one end of the hub axle 41, a hub shell 43 that is located around the outer periphery of the hub axle 41 and driver 42, a planet gear mechanism 44 for transmitting motive power between the driver 42 and the hub shell 43, and a sound-generating mechanism 100 for antitheft purposes. The planet gear mechanism 44 is made up of a total of four steps, one direct and three speed-increasing.
The driver 42 is a roughly cylindrical member, one end of which is rotatably supported by the hub axle 41 via balls 45 and a hub cone 46. A hub cog 47 is fixed as an input element around the outer periphery at one end. A notch 42a that expands outward in the radial direction from the space in the center is formed in the driver 42. Three of these notches 42a are formed at roughly equal angles in the circumferential direction.
The hub shell 43 is a cylindrical member having a plurality of steps in the axial direction, and the driver 42 is housed in a housing space 43a around the inner periphery thereof. One side of the hub shell 43 is rotatably supported around the outer periphery of the driver 42 via balls 50, and the other by the hub axle 41 via balls 51 and a hub cone 52. Flanges 53 and 54 for supporting the spokes 7a (FIG. 1) of the rear wheel 7 are fixed around the outer periphery at both ends of the hub shell 43. A cover 55 is fixed to the outer side wall at one side of the driver 42, and the distal end of the cover 55 extends so as to cover the outer peripheral surface at one end of the hub shell 43. A sealing member 56 is positioned between the inner peripheral surface at the distal end of the cover 55, and the outer peripheral surface of the hub shell 43.
The planet gear mechanism 44 is housed in the housing space 43a inside the hub shell 43, and has first, second, and third sun gears 60, 61, and 62, three planet gears 63(a-c) (only one planet gear is shown in the figures) that mesh with these, and a ring gear 64. The sun gears 60 to 62 are lined up in the axial direction around the inner periphery of the driver 42 and the outer periphery of the hub axle 41, and furthermore are allowed to rotate relative to the hub axle 41. The planet gears 63 are rotatably supported via a support pin 65 within the notches 42a in the driver 42. A first gear 63a, a second first gear 63b, and a third gear 63c are formed integrally with the planet gears 63. The first gear 63a meshes with the first sun gear 60, the second gear 63b meshes with the second sun gear 61, and the third gear 63c meshes with the third sun gear 62. The ring gear 64 is located on the outer peripheral side of the planet gears 63, and inner teeth are formed around the inner periphery. This ring gear 64 meshes with the second gear 63b of the planet gears 63.
As shown in FIGS. 5 to 8, a pair of stopping protrusions 41 a are formed at the locations where the sun gears 60 to 62 are disposed. Four housing spaces 60a to 62a are formed apart from each other in the peripheral direction around the inner periphery of the sun gears 60 to 62. The first sun gear 60 is depicted in FIGS. 5 and 7, whereas the third sun gear 62 is depicted in FIGS. 6 and 8. Between the hub axle 41 and the inner periphery of the sun gears 60 to 62 are positioned a selective clutch mechanism 70 for preventing the sun gears 60 to 62 from performing relative rotation in the forward direction or for allowing them to rotate relative to the hub axle 41, a lock mechanism 90 for preventing the third sun gear 62 from performing relative rotation in the opposite direction from the forward direction or for allowing it to perform relative rotation, and an actuation mechanism 91 for actuating the selective clutch mechanism 70 and the lock mechanism 90. These actuation mechanism 91, lock mechanism 90, and sound-generating mechanism 100 constitute an antitheft device.
The selective clutch mechanism 70 has a function whereby it selectively links one of the three sun gears 60 to 62 to the hub axle 41, and a function whereby it does not link any of the sun gears 60 to 62 to the hub axle 41. The selective clutch mechanism 70 has a plurality of drive pawls 71, 72, and 73 that are disposed in the housing spaces 60a to 62a of the sun gears 60 to 62, and the distal ends of which are able to mesh with the stopping protrusions 41a of the hub axle 41, and has annular wire springs 74, 75, and 76 for energizing the distal ends of the drive pawls 71 to 73 toward the hub axle 41. The drive pawls 71 to 73 are swingably supported at their base ends in the pawl housing spaces 60a to 62a where they face each other, and are able to mesh at their distal ends with the stopping protrusions 41a. When the drive pawls 71 to 73 are stopped by the stopping protrusions 41a of the hub axle 41 and thereby linked to the hub axle 41, the sun gears 60 to 62 are no longer able to rotate in the forward direction (clockwise in FIG. 5) in relation to the hub axle 41 but can perform relative rotation in the opposite direction (counterclockwise in FIG. 5). When the drive pawls are released, relative rotation is possible in both directions.
The lock mechanism 90, as shown in FIG. 6, has a pair of lock pawls 92 which are capable of meshing at their distal ends with the stopping protrusions 41a of the hub axle 41 at the inner surface of the third sun gear 62 and which are positioned in the pawl housing space 62a of the third sun gear 62. The distal ends of the lock pawls 92 are energized toward the hub axle 41 by the wire spring 76 that energizes the drive pawls 73. The lock pawls 92 are swingably supported at their base ends in another pawl housing space 62a opposite from the pawl housing space 62a in which the drive pawl 73 is housed, and they are capable of meshing at their distal ends with the stopping protrusions 41a on the opposite side from the drive pawls 73. When the lock pawls 92 are stopped by the stopping protrusions 41a of the hub axle 41 and thereby linked to the hub axle 41, the third sun gear 62 is no longer able to rotate relatively in the opposite direction from the forward direction (counterclockwise in FIG. 6), but is able to rotate relatively in the forward direction (clockwise in FIG. 6). When the lock pawls are released, relative rotation is possible in both directions.
The actuation mechanism 91 has a sleeve 77. The sleeve 77 is rotatably fitted over the outer periphery of the hub axle 41, and has a plurality of drive cam components 94a and lock cam components 94b at the locations where the drive pawls 71 to 73 and the lock pawls 92 are disposed on the outer periphery. When these drive cam components 94a strike any of the drive pawls 71 to 73, and the lock cam components 94b strike lock pawls 92, the struck pawls are raised, and the linkage between the hub axle 41 and the sun gears 60 to 62 is released by these pawls. An operator 78 is fixed to one end of the sleeve 77, and the sleeve 77 can be rotated by the rotation of the operator 78. The rotation of the sleeve 77 then causes the cam components 94 to selectively actuate the drive pawls 71 to 73 and the lock pawls 92, so that the linkage and locking of the sun gears 60 to 62 with the hub axle 41 are controlled.
As shown in FIG. 4, a reduction mechanism 95 is linked to the operator 78. The reduction mechanism 95 reduces the speed of rotation of the shift motor 29, and transmits rotation to the operator 78. The actuation position sensor 26, which is used to fix the sleeve 77 of the internal shifting hub 10 in one of the actuation positions VP (in one of the shift positions V1 to V4 of the speed steps or in the locked position PK), is disposed inside the reduction mechanism 95.
With a structure such as this, a large speed-increasing power transmission path with the largest speed increasing ratio is created when the drive pawl 71 strikes a stopping protrusion 41a of the hub axle 41, and the first sun gear 60 is selected; a medium speed-increasing power transmission path with the second-largest speed increasing ratio is created when the second sun gear 61 is selected; and a small speed-increasing power transmission path with the smallest speed increasing ratio is created when the third sun gear 62 is selected. If none of the sun gears has been selected, then a direct-coupled power transmission path is created. Also, when the lock pawls 92 strike the stopping protrusions 41a of the hub axle 41, rotation of the third sun gear 62 is locked in the opposite direction from the forward direction, and when another sun gear (such as the first sun gear 60) is linked with the hub axle 41 by the drive pawls, the internal shifting hub 10 is locked.
A first one-way clutch 80 is provided between the inner peripheral surface of the hub shell 43 and the outer peripheral surface at the other end of the driver 42. A second one-way clutch 81 is provided between the inner peripheral surface of the hub shell 43 and the outer peripheral surface of the ring gear 64. These one-way clutches 80 and 81 are both roller-type, one-way clutches, which reduces noise during idle running when a shift is made, softens the shock when a shift is made, and allows for smoother shifting.
The sound-generating mechanism 100 is provided to the left end (in FIG. 4) of the hub axle 41 within the hub shell 43. As shown in FIGS. 9 to 11, the sound-generating mechanism 100 has a spring washer 101 that rotates integrally with the sleeve 77, a noise-emitting cam 102 positioned on the hub axle 41 such that it is able to move in the axial direction but unable to rotate, a noise-emitting washer 103 that presses against the noise-emitting cam 102, and a noise-emitting spring 104 disposed in a compressed state between the noise-emitting washer 103 and the hub cone 52.
The spring washer 101 is a member that is nonrotatably stopped by the sleeve 77, and it has around its outer periphery an engagement tab 105 that strikes the noise-emitting cam 102. The noise-emitting cam 102 has a cylindrical cam body 106 and a stopping washer 107 that stops the cam body 106 and the hub axle 41 such that they can move in the axial direction but cannot rotate. A cam component 108 that strikes the engagement tab 105 is formed at the right end (in FIG. 11) of the cam body 106. The cam component 108 is formed such that the cam body 106 is moved axially to the left by the rotation of the sleeve 77 toward the locked position PK. A large number of noise-emitting grooves 109 are formed at regular intervals in the circumferential direction at the left end of the cam body 106. The noise-emitting grooves 109 are inclined in the forward direction.
The noise-emitting washer 103 has a disk-shaped washer body 110 and a ratchet pawl 111 that is swingably supported on the washer body 110. Numerous noise-emitting tabs 112 that engage with the noise-emitting grooves 109 are formed around the outer periphery of the washer body 110. The ratchet pawl 111 is able to mesh with ratchet teeth 113 formed in the inner peripheral surface of the hub shell 43 when the hub shell 43 rotates in the forward direction. This sound-generating mechanism 100 emits noise through the vibration of the noise-emitting washer 103 when the sleeve 77 is in the locked position and when the rear wheel 7 rotates in the forward direction.
Shifting and locking are performed by actuating the shift motor 29 through mode selection with the control dial 23 of the shift control element 9, through shift operation with the control buttons 21 and 22, and through rotating the sleeve 77 via the operator 78. FIG. 12 is a flow chart illustrating the actuation and control of the shift control component 25.
When the power is turned on, initialization is performed in step S1. Here, circumference data used for calculating speed is set to a diameter of 26 inches, and the speed step is set to second gear (V2). In step S2, a decision is made as to whether the control dial 23 has been set to the parking mode. In step S3, a decision is made as to whether the control dial has been set to the automatic shift mode. In step S4, a decision is made as to whether the control dial 23 has been set to the manual shift mode. In step S5, a decision is made as to whether some other processing, such as tire diameter input, has been selected.
When the control dial 23 is turned to position P and set to the parking mode, the flow goes from step S2 to step S10. In step S10, the dial P processing shown in FIG. 13 is executed. When the control dial 23 is turned to position A and set to the automatic shift mode, the flow goes from step S3 to step S11. In step S11, the automatic shift processing shown in FIG. 15 is executed. When the control dial 23 is turned to position M and set to the manual shift mode, the flow goes from step S4 to step S12. In step S12, the manual shift processing shown in FIG. 16 is executed. When other processing is selected, the flow goes from step S5 to step S13, and the selected processing is executed.
With the dial P processing in step S10, a decision is made as to whether 30 seconds has elapsed since the dial was turned to position P in step S21 in FIG. 13. In step S22, a decision is made as to whether the password PW has been registered. This decision is made on the basis of whether the password PW has already been stored in the memory component 30. If the password has already been registered, the flow moves on to step S23.
In step S23 a decision is made as to whether the left control button 21 has been operated. The purpose of operating the control buttons 21 and 22 here is to input the password for unlocking the locked internal shifting hub 10. In step S24 a decision is made as to whether the right control button 22 has been operated. In step S25 a decision is made as to whether the password LR inputted by operation of the two control buttons 21 and 22 matches the registered password PW. If there is no match, the flow moves on to step S26. In step S26 a decision is made as to whether the password still does not match after it has been inputted three times. If it has yet to be inputted three times, the flow returns to step S23, and the re-inputting of the password is permitted. If the password does not match the registered password PW after three inputs, the flow moves on to step S27. In step S27, the system waits for 10 minutes to pass, and when 10 minutes have elapsed, the flow returns to step S23, and the re-inputting of the password is permitted.
Once 30 seconds have elapsed since the dial was turned to the P position, the flow moves from step S21 to step S30. In step S30, the shift motor 29 is driven by the motor driver 28, and the actuation position VP is set to the locked position PK. As a result, the sleeve 77 is rotated via the operator 78, the drive pawl 71 is raised as shown in FIGS. 7 and 8 so that the first sun gear 60 and the hub axle 41 are locked in just the forward direction, and the lock pawls 92 are raised so that the third sun gear 62 and the hub axle 41 are nonrotatably locked in the opposite direction from the forward direction. When the two sun gears 60 and 62 are thus locked, if an attempt is made to rotate the driver 42 by rotating the crank gear 18, the system will try to make the largest upshift since the first sun gear 60 is locked in the forward direction, but since the third sun gear 62 cannot turn backward, the planet gear mechanism 44 is locked and cannot move. Accordingly, the bicycle cannot be pedaled away, making its theft more difficult.
If the bicycle is pushed by hand at this point, the one-way clutch 80 will allow it to move forward even if the planet gear mechanism 44 is locked. If, however, the sleeve 77 is rotated to the locked position PK, the cam body 106 of the sound-generating mechanism 100 will be pressed by the engagement tab 105 of the spring washer 101 that rotates along with the sleeve 77, and will move from the position indicated by (A) in FIGS. 9 and 11 to the positions indicated by (B) and (C) in FIGS. 10 and 11 (that is, will move to the left in the axial direction). As a result, the ratchet pawl 111 of the noise-emitting washer 103 meshes with the ratchet teeth 113 of the hub shell 43, and rotates integrally with the hub shell 43 only in the forward direction. At this point, the noise-emitting tabs 112 of the noise-emitting washer 103 go in and out of the noise-emitting grooves 109 of the noise-emitting cam 102, creating a loud impact sound. Consequently, a loud noise is produced when the bicycle is pushed by hand in a locked state, and this also deters theft.
If the password PW has not been registered, the flow moves from step S22 to step S31. In step S31, the code registration processing illustrated in FIG. 14 is executed. Here, a decision is made as to whether the control button 21 was operated in step S41 in FIG. 14. If the control button 21 was operated, the flow moves to step S42, and the left number L (a 10-digit number) is increased by one. In step S43 a decision is made as to whether the control button 22 was operated. The flow returns to step S41 until the control button 22 is pushed, and the left number L is increased by one. When the control button 22 is operated, the flow moves to step S44, and the right number R (a 1-digit number) is increased by one. In step S45 a decision is made as to whether the control button 21 was operated again. The flow returns to step S43 until the control button 21 is operated, and the right number R is increased by one. When the control button 21 is operated, the flow moves to step S46, and the inputted number LR is stored as the password PW in the memory component 30. A password PW is thus registered after being selected from among 100 two-digit numbers LR ranging from "00" to "99."
In step S23, if it is decided that the control button 21 was operated during unlocking, the flow moves on to step S32. In step S32 the left number L is increased by one, just as when the password was registered. If it is decided that the control button 22 was operated, the flow moves from step S24 to step S33. In step S32, the right number R is increased by one, just as when the password was registered. If the inputted number LR matches the password PW in step S25, the flow moves to step S34, and the actuation position VP is set to first gear V1. As a result, the sleeve 77 is rotated by the shift motor 29 and positioned at the first gear V1, the lock pawl 92 of the third sun gear 62 comes out, and all of the drive pawls 71 to 73 come out. This means that all of the sun gears 60 to 62 are free to rotate with respect to the hub axle 41. As a result, when the bicycle is pedaled, the rotation of the driver 42 is transmitted directly to the hub shell 43 via the first one-way clutch 80.
With the automatic shift processing of step S11, the actuation position VP is set to a speed step corresponding to the bicycle speed SP. When the position is different from this, shifts are made one gear at a time toward this. Here, in step S51 in FIG. 15, a decision is made as to whether the bicycle speed SP is at or below the speed S1 on the basis of the speed signal from the bicycle speed sensor 12. In step S52 a decision is made as to whether the bicycle speed SP is over the speed S1 and at or below the speed S2. In step S53 a decision is made as to whether the bicycle speed SP is over the speed S2 and at or below the speed S3 In step S54 a decision is made as to whether the bicycle speed SP is over the speed S3.
When the bicycle speed SP is low (at or below the speed S1), the flow moves from step S51 to step S55. In step S55 a decision is made as to whether the current actuation position VP is first gear V1. If the actuation position VP is not first gear V1, the flow moves on to step S56, and the actuation position VP is adjusted to first gear V1 one speed step at a time. If the bicycle speed SP is medium low (over the speed S1 and at or below the speed S2), the flow moves from step S52 to step S57. In step S57 a decision is made as to whether the current actuation position VP is second gear V2. If the actuation position VP is not second gear V2, the flow moves on to step S58, and the actuation position VP is adjusted to second gear V2 one speed step at a time. If the bicycle speed SP is medium high (over the speed S2 and at or below the speed S3), the flow moves from step S53 to step S59. In step S59 a decision is made as to whether the current actuation position VP is third gear V3. If the actuation position VP is not third gear V3, the flow moves on to step S60, and the actuation position VP is adjusted to third gear V3 one speed step at a time. If the bicycle speed SP is high (over the speed S3), the flow moves from step S54 to step S61. In step S61 a decision is made as to whether the current actuation position VP is fourth gear V4. If the actuation position VP is not fourth gear V4, the flow moves on to step S62, and the actuation position VP is adjusted to fourth gear V4 one speed step at a time.
Here, when the first sun gear 60 and the hub axle 41 are linked by the shift motor 29, the bicycle is in fourth gear V4, the rotation inputted from the chain wheel to the driver 42 is increased by the largest gear ratio determined by the number of teeth on the first sun gear 60, the first gear 63a and second gear 63b of the planet gears 63, and the ring gear 64, and this rotation is transmitted to the hub shell 43 via the second one-way clutch 81. When the second sun gear 61 is selected and linked to the hub axle 41, the bicycle is in third gear V3, the rotation of the driver 42 is increased by a medium (the second largest) gear ratio determined by the number of teeth on the second sun gear 61, the second gear 63b of the planet gears 63, and the ring gear 64, and this rotation is transmitted to the hub shell 43 via the second one-way clutch 81. When the third sun gear 62 is selected and linked to the hub axle 41, the bicycle is in second gear V2, the rotation of the driver 42 is increased by the smallest gear ratio determined by the number of teeth on the third sun gear 62, the second gear 63b and third gear 63c of the planet gears 63, and the ring gear 64, and this rotation is transmitted to the hub shell 43 via the second one-way clutch 81. If none of the sun gears 60 through 62 is selected, first gear V1 is engaged, and the rotation of the driver 42 is transmitted directly to the hub shell 43, as above. Unselected sun gears perform relative rotation in the opposite direction from the forward direction with respect to the hub axle 41. When any one of the sun gears is selected and speed is stepped up by the planet gear mechanism 44, the driver 42 and the hub shell 43 perform relative rotation in the direction in which meshing with the first one-way clutch 80 is released.
With the manual shift processing of step S11, gear shifts are made one at a time by operation of the control buttons 21 and 22. In step S71 in FIG. 16 a decision is made as to whether the control button 21 was operated. In step S72 a decision is made as to whether the control button 22 was operated. When the control button 21 is operated, the flow moves from step S71 to step S73. In step S73 a decision is made as to whether the current actuation position VP is fourth gear V4. If the current actuation position VP is fourth gear V4, the flow moves on to step S74, and fourth gear V4 is maintained without a shift being made. If the current actuation position VP is not fourth gear V4, then the flow moves to step S75, and the actuation position VP is moved one speed step higher. When the control button 22 is operated, the flow moves from step S71 to step S73. In step S73 a decision is made as to whether current actuation position VP is first gear V1. If the current actuation position VP is first gear V1, the flow moves on to step S77, and first gear V1 is maintained without a shift being made. If the current actuation position VP is not first gear V1, the flow moves to step S78, and the actuation position VP is moved one speed step lower. During these shifts, the sensing results from the actuation position sensor 26 are compared with the positional data for each actuation position stored ahead of time in the memory component 30, the results of which are used to perform positioning control of the shift motor 29.
Thus, according to this embodiment, entering the parking mode with the aid of the control dial 23 allows this mode to be maintained as long as the entered password does not match the registered password, and hence impedes the unlocking of the antitheft device containing the lock mechanism 90. In addition, entering the parking mode with the aid of the control dial 23 allows the planetary gear mechanism 44 to be locked by the lock mechanism 90 and the sound-generating mechanism 100 to produce a sound, making it impossible for an unauthorized person to pedal the bicycle away and generating a sound when the bicycle is pushed. This arrangement can minimize bicycle theft.
In the above-described embodiment, a lock mechanism 90 was provided between a hub axle 41 and a sun gear 62 that performed relative rotation, and a sound-generating mechanism 100 was separately provided between the hub axle 41 and the hub shell 43 to prevent theft. It is also possible, however, to position an antitheft device 85 endowed with sound-generating and locking functions between the hub axle 41 and the hub shell 43, that is, to provide the device to a running component that performs relative rotation as shown in FIG. 17.
As shown in FIG. 17, an internal shifting hub 10a has an antitheft device 85 in which the sound-generating mechanism 100 in FIG. 4 is endowed with a locking function in addition to a sound-generating function. The sun gear 62 is therefore devoid of any lock pawls. Except for the presence of the antitheft device 85, this embodiment has the same structure and operation as embodiment shown in FIG. 4, and the corresponding description will therefore be omitted.
The antitheft device 85 is provided to the left end (in FIG. 17) of the hub axle 41 within the hub shell 43. As shown in FIGS. 18 through 20, the antitheft device 85 has a spring washer 101a that rotates integrally with the sleeve 77, a moving cam 102a, a moving member 103a, a moving spring 104a, and a lock ring 114. The moving cam 102a is nonrotatably installed while allowed to move axially in relation to the hub axle 41. The moving member 103a presses against the moving cam 102a, the moving spring 104a is disposed in a compressed state between the moving member 103a and a hub cone 52, and the lock ring 114 is pressed against the moving member 103a.
The spring washer 101a is a member that is nonrotatably stopped by the sleeve 77, and it has around its outer periphery an engagement tab 105a that strikes the moving cam 102a. The moving cam 102a has a cylindrical cam body 106a and a stopping washer 107a that stops the cam body 106a and the hub axle 41 such that they can move in the axial direction but cannot rotate. A cam component 108a that strikes the engagement tab 105a is formed at the right end (in FIG. 20) of the cam body 106a. The cam component 108a is formed such that the cam body 106a is moved axially to the right by the rotation of the sleeve 77 toward the locked position PK.
The moving member 103a has a disk-shaped flange component 115 and a cylindrical component 116 integrally formed along the inner periphery of the flange component 115. A step 115a is formed on the flange component 115 in its midportion as viewed in the radial direction. A lock ring 114 is rotatably supported by the step 115a. As shown in FIG. 21, respective radial irregularities 114a (only those located on the side of the lock ring 114 are shown) are formed on the surface of the flange component 115 facing the lock ring 114 and on the surface of the lock ring 114 facing the flange component 115. The presence of such irregularities 114a increases the frictional force between the lock ring 114 and the moving member 103a and causes these components to vibrate and to produce sound during relative rotation. Serration teeth 114b are formed in the outer peripheral portion of the lock ring 114, as shown in FIG. 21. These serration teeth 114b can engage with serration teeth 113a formed in the inner peripheral surface of the hub shell 43.
Four protrusions 116a are formed on the inner peripheral surface of the cylindrical component 116 as shown in FIG. 21. The protrusions 116a engage four grooves 41c formed in the outer peripheral surface of the hub axle 41. As a result of this arrangement, the moving member 103a is nonrotatably supported by the hub axle 41 while allowed to move in the axial direction. A thread and a stopping groove are formed in the outer peripheral surface of the cylindrical component 116. A pressure ring 117 is mounted around the outside of the cylindrical component 116 as shown in FIG. 18. The pressure ring 117, which is nonrotatably supported on the cylindrical component 116 while allowed to move in the axial direction, is allowed to come into contact with the lock ring 114. In addition, a pressure nut 118 is screwed on the outer periphery at the right end of the cylindrical component 116. A coned disk spring 119 is disposed between the pressure nut 118 and the pressure ring 117.
The pressure exerted by the coned disk spring 119 can be adjusted by adjusting the fastening of the pressure nut 118; the frictional force between the lock ring 114 and the flange component 115 of the moving member 103a can be adjusted via the pressure ring 117; and the rotation of the hub shell 43 can be controlled arbitrarily. For example, maximizing the frictional force produced by the coned disk spring 119 makes it possible to bring the system into a locked state with minimal rotation of the hub shell 43. Furthermore, reducing the frictional force weakens the force with which the rotation of the hub shell 43 is controlled and allows the hub shell 43 to rotate in relation to the hub axle 41. In this case as well, a frictional force is generated when the coned disk spring 119 is energized, and the rotation is controlled, unlike in a free-rotating state. This embodiment allows the rotation of the hub shell 43 (that is, the rotation of the rear wheel 7) to be freely controlled by adjusting the energizing force of the coned disk spring 119 within a range that extends essentially from the locked state to the free-rotating state.
In the antitheft device 85 thus configured, the engagement tab 105a of the spring washer 101a rotating along the sleeve 77 moves into the cam component 108a when the sleeve 77 is rotated from a shift position to the locked position PK. When the engagement tab 105 moves into the cam component 108a, the moving cam 102a and the moving member 103a energized by the moving spring 104a move to the right from the position designated as (A) in FIGS. 18 and 20 to the position designated as (B) in FIGS. 19 and 20. As a result of this, the serration teeth 114b of the lock ring 114 engage with the serration teeth 113a of the hub shell 43, and the rotation of the hub shell 43 is controlled by the force of friction between the lock ring 114 and the moving member 103a. The corresponding frictional force can be altered as needed by adjusting the energizing force of the coned disk spring 119 through the tightening of the pressure nut 118. Therefore, pedaling fails to rotate the rear wheel 7 or rotates it only slightly.
At this time, an attempt to forcefully turn the hub shell 43 results in the relative rotation of the moving member 103a and the lock ring 114 and causes the lock ring 114 and the moving member 103a to vibrate and to emit a loud vibrating noise under the action of the irregularities 114a. Thus, loud noise is produced when the bicycle is pressed by hand or the pedals are pressed and the hub shell 43 is rotated in the locked state, making the bicycle more difficult to steal. Another feature is that even when the sleeve 77 is mistakenly placed in the locked position by an accidental action during riding, the rear wheel 7 is still prevented from being locked abruptly because the rotation of the rear wheel 7 is controlled by friction.
In the first embodiment described above, the sun gears are locked to prevent the bicycle from being pedaled away when the sleeve 77 is in the locked position. However, the bicycle can still be moved by pushing. By contrast, this embodiment entails directly coupling the hub shell 43 with the hub axle 41 to achieve locking. This controls the rotation of the hub shell 43 (and rear wheel 7) even when an attempt is made to push the bicycle, making it more difficult to push the bicycle and reducing the likelihood of a theft.
Although the two embodiments described above referred to internal shifting hubs 10 and 10a in which an operator 78 was actuated by a motor, it is also possible to rotate a sleeve and to perform shifting and antitheft locking by linking a shift control element and an operator with the aid of a shifting cable, and by mechanically operating the shift control element. For example, in FIG. 22 the shift control element 9a has a body unit 160 formed integrally with the right-side brake lever 16 and a control element 161 rotatably mounted on the body unit 160. The body unit 160 has a circular display component 162 for displaying a shift position or the parking position and a lock component 163 for maintaining the control element 161 in the parking position when this position has been reached.
The display component 162 has a transparent dial 164 on which numbers indicating shift positions 1 through 4 and a letter indicating parking position P are marked at regular intervals in the circumferential direction, and an indicator 165 that rotates in conjunction with the rotation of the control element 161 on the reverse side of the dial 165. The indicator 165 points to one of the five positions comprising a parking position and four shift positions.
As shown in FIG. 23, the lock component 163 has a cylindrical lock 170, a lock cam 171 that rotates in conjunction with the cylindrical lock 170, a lock body 172 actuated by the lock cam 171, and a leaf spring 173 for energizing the lock body 172 to the right in FIG. 23.
The lock cam 171 is an oval member that is rotated by the rotating cylindrical lock 170, assuming a normal position achieved during shifting and shown in FIG. 23A as a straight-up position, an open position achieved by a 45-degree turn to the left from the normal position and shown in FIG. 23B, and a locked position achieved by a 90-degree turn to the right from the normal position and shown in FIG. 23C.
The lock body 172 is a rectangular member provided with a rectangular opening 172a in the center and supported while allowed to move to the left and right in FIG. 23 inside a rectangular opening 160a formed within the body unit 160. The outer peripheral surface of the lock cam 171 presses against the inner peripheral surface of the opening 172a in the lock body 172. The vertical dimension of the opening 172a [is] considerably greater than the lengthwise dimension of the lock cam 171. In addition, the transverse dimension is slightly greater than the medium lengthwise dimension of the lock cam 171 so that the lock body 172 cannot move in any significant way to the right or left when the lock cam 171 is in the locked position. A rectangular stopping protrusion 174 is formed on the lateral surface of the lock body 172 facing the control element 161.
The end face of the control element 161 facing the body unit is provided with a stopping groove 166 that is stopped by the stopping protrusion 174 in the locked position and with a movement groove 167 that faces the stopping protrusion 174 in the normal position. A protrusion 168 between the movement groove 167 and the stopping groove 166 functions as a stopper for preventing the system from leaving a shift position and moving to the parking position in the normal running state even when the control element 161 is actuated by striking the stopping protrusion 174.
The control element 161 is supported by the body unit 160 while allowed to be placed in five positions: a parking position and four shift positions. The shift positions can be changed by the rotation of the control element 161 with the thumb and the index finger. The control element 161 is linked to a cable winder (not shown) provided to the body unit 160, and the inner cable of a shifting cable 180 whose tip is fixed to the cable winder is taken up or paid out by rotation. The tip of the inner cable of the shifting cable 180 is linked to the operator 78.
When the shift control element 9a is in the normal position (FIG. 23A), that is, when the cylindrical lock 170 is not engaged, the control element 161 can be turned to one of the four shift positions because the stopping protrusion 174 is positioned in the movement groove 167. When a key is inserted into the cylindrical lock and turned 45 degrees to the left, the lock cam 171 is rotated in the same manner, and the open position is reached. At this time, the lock body 172 is allowed to move to the left in FIG. 23 in opposition to the energizing force of the leaf spring 173 (FIG. 23B). This releases the stopped state formed by the striking of the protrusion 168 and the stopping protrusion 174, and allows the control element 161 to rotate to the parking position. The stopping protrusion 174 faces the stopping groove 166 when the control element 161 is rotated to the parking position. When the key is turned 135 degrees to the right from the open position in this state, the lock cam 171 is rotated in the same manner and is moved to the locked position. At this time, the lock body 172 is moved to the left in FIG. 23 by the energizing force of the leaf spring 173 (FIG. 23C). As a result, the stopping protrusion 174 engages the stopping groove 166, and the control element 161 is nonrotatably locked. The lock cam 171 is maintained in the parking state in the locked position if the key is removed from the cylindrical lock 170 in this state.
Conversely, to release the parking state the key is inserted into the cylindrical lock 170 and turned 135 degrees to the left, placing the lock cam 171 in the open position. When this is done, the lock body is moved to the left, allowing the control element 161 to be rotated. The lock cam 171 is placed in the normal position when the key is turned 45 degrees to the right after the control element 161 has been placed in one of the shift positions. In this state, the lock body 172 is moved to the right by the energizing force of the leaf spring 173, and the stopping protrusion 174 is placed into the movement groove 167. In this state, the control element 161 can move solely among the four shift positions, as described above. As a result, the parking position cannot be engaged even by mistake. In this state, the key is removed and riding is started.
As shown in FIG. 24, an internal shifting hub 10b has essentially the same structure as the one shown in FIG. 17, the difference being that a shifting cable is directly linked to the operator 78. The embodiment shown in FIG. 17 contemplates an arrangement in which the operator 78 is turned by the motor 29, whereas the embodiment shown in FIG. 24 contemplates an arrangement in which the operator 78 is turned by the shifting cable. In all other respects the structure is the same as in the embodiment shown in FIG. 17, and the corresponding description will therefore be omitted.
This embodiment contemplates an arrangement in which rotating the control element 161 of the shift control element 9a into the parking position results in the rotation of the operator 78, in the corresponding rotation of the sleeve 77 to the locked position PK, and in the controlled rotation of the internal shifting hub 10b so that a sound is produced when the hub shell 43 is rotated. As a result, the likelihood of a theft is reduced and bicycle theft is prevented in the same manner as in the two embodiments described above. In addition, placing the control element 161 in the parking position makes it possible for this state to be maintained by the cylindrical lock 170, so a return to a shift position is impossible until the cylindrical lock 170 is unlocked. This impedes the unlocking of the antitheft device 85 in the antitheft position and makes theft less likely.
Although the three embodiments described above referred to an internal shifting hub for a rear wheel 7, it is also possible to mount the antitheft device 85 inside a front hub 120 for a front wheel 6 as shown in FIG. 25. In this embodiment the front hub 120 has a hub axle 41b and a hub shell 43b rotatably supported on the hub axle 41b. Serration teeth 113b are formed in the inner peripheral surface of the hub shell 43b. A sleeve 77a is rotatably mounted around the outside of the hub axle 41b, and a lock lever 121 is rotatably mounted in the base-end portion of the sleeve 77a. The structure of the antitheft device 85 is the same as in the second embodiment above, and the corresponding description will therefore be omitted.
In this embodiment, a lock control element is disposed, for example, on the handlebar 15. This lock control element may have essentially the same structure as the shift control element 9a. Specifically, the lock control element may be equipped with a body unit and a control element. The control element may move among the parking position and riding positions. These riding positions correspond to the plurality of shift positions. The lock control element is provided with a means that allows a cylindrical lock or the like to be locked with a key in the parking position and that prevents a return from the parking position to a riding position unless a numeric password has been inputted, a key inserted, or another such unlocking operation performed. It is possible to link such a lock control element and the lock lever 121 with the aid of a cable, to allow the lock control element to rotate the sleeve 77a, and to move the moving member between a locked position and an unlocked position.
Although the embodiments described above involved providing a wheel hub with an antitheft device, it is also possible to mount the antitheft device 85a inside the internal shift crank 130 of a drive component 5, as shown in FIG. 26. In this embodiment the internal shift crank 130 can be locked or shifted between two steps (high and low). The internal shift crank 130 has a bottom bracket 132 (which has a crank axle 131 that is mounted on the bottom bracket component 2a of the bicycle frame body 2), left and right crank arms 133a and 133b, a planetary gear mechanism 134, a crank gear 135 linked to the planetary gear mechanism 134, and an antitheft device 85a provided to the planetary gear mechanism 134.
The crank axle 131 is rotatably supported on the cylindrical bottom bracket 132, and the crank arms 133a and 133b are nonrotatably mounted at both ends with the aid of a mounting bolt 140. The bottom bracket 132 has a cylindrical bracket body 141 for supporting the crank axle 131, a case component 142 integrally formed at the right end of the bracket body 141, and an attaching bolt 143 mounted on the left end of the bracket body 141. The bottom bracket 132 is mounted on the bottom bracket component 2a by tightening, with the aid of the attaching bolt 143, the bracket body 141 inserted into the bottom bracket component 2a, and is nonrotatably stopped in relation to the frame body 2 by a fixing arm 144 mounted on the case component 142. The case component 142, which is designed to house the planetary gear mechanism 134 in its interior, has a disk component 142a disposed at the right end of the bracket body 141 and a cylindrical component 142b extending to the right in FIG. 26 away from the outer peripheral portion of the disk component 142a.
As shown in FIG. 27, the planetary gear mechanism 134 has a ring gear 145 formed on the inner peripheral surface of the cylindrical component 142b, three planetary gears 146 (only one is shown in FIG. 27) that mesh with this ring gear 145, and a sun gear 147 that meshes with the planetary gears 146.
The planetary gears 146 are arranged at regular intervals in the circumferential direction around an annular frame body 148 fixed to the crank gear 135, and they are rotatably supported on the frame body 148. The frame body 148 is rotatably supported by a crank arm 133b and the case component 142, and a swingable drive pawl 155 is disposed around the inside of this frame body. Only the forward rotation of the crank axle 131 is transmitted by the drive pawl 155 to the frame body 148.
The frame body 148 can be rotated by the drive pawl 155 only in the forward direction integrally with the crank axle 131. In addition, a large number of stopping grooves 148a are radially formed in the left-side surface of the frame body 148. The planetary gears 146 have a large gear tooth 146a and a small gear tooth 146b. The large gear tooth 146a meshes with the ring gear 145, and the small gear tooth 146b meshes with the sun gear 147.The sun gear 147 is rotatably mounted on the crank axle 131. A drive pawl 149 is disposed inside the sun gear 147, which is rotated by the drive pawl 149 in conjunction solely with the forward rotation of the crank axle 131.
A switching disk 151 is nonrotatably mounted around the inside of the cylindrical component 142b of the case component 142 while allowed to move in the axial direction. The switching disk 151 is axially moved by the turning of a switching lever 152. The switching disk 151 is also energized to the left in FIG. 27 by an energizing means (not shown). The switching lever 152 is swingably supported by the case component 142, an inclined cam (not shown) is formed on the lateral surface that strikes this switching disk 151, and the switching disk 151 is moved in the axial direction by turning. A shifting cable is mounted on the upper end. The shift control element has, for example, three positions (high-speed position, low-speed position, and parking position) and can be locked in the parking position to allow this position to be preserved. This shift control element may be essentially the same as that disclosed in relation to the third embodiment.
A radial stopping groove 151a capable of meshing with the stopping grooves 148a formed in the frame body 148 are formed in the right-side surface of the switching disk 151. Together with the switching disk 151, these stopping grooves 148a and 151a constitute the antitheft device 85a. In addition, a switching pawl 151b designed to turn the drive pawl 155 without driving is formed at the right end around the inside of the switching disk 151. Furthermore, a tooth component 151c for meshing with the cylindrical component 142b is formed around the outside of the switching disk 151.
The crank gear 135 rotates integrally with the frame body 148. The crank gear 135 is rotatably supported by the crank arm 133b and the case component 142 via the frame body 148. When the shift control element is turned to the high-speed position in the internal shift crank 130 thus configured, the switching lever 152 is turned via the shifting cable (as shown in FIG. 27A), and the switching disk 151 is moved to the high-speed position on the left side. In this state, the frame body 148 and the crank axle 131 are linked by the drive pawl 155. As a result, the forward rotation of the crank axle 131 is directly transmitted to the frame body 148, and the crank gear 135 is rotated at the same rotational speed as the crank axle 131.
When the shift control element is turned to the low-speed position, the switching lever 152 is turned via the shifting cable as shown in FIG. 27B, and the switching disk 151 is moved to the low-speed position in the center. In this state, the drive pawl 155 is turned by the switching pawl 151b of the switching disk 151, and the drive pawl 155 cannot perform driving. As a result, the link between the frame body 148 and the crank axle 131 is released. When this is done, the forward rotation of the crank axle 131 is transmitted to the sun gear 147 via the drive pawl 149. When the sun gear 147 is rotated in the forward direction, the planetary gear 146 rotates around its axis in the opposite direction and revolves around the sun gear in the forward direction at a reduced speed. As a result, the crank gear 135 rotates at a reduced speed via the frame body 148.
When the shift control element is turned to the parking position, this state is preserved by the input of a password, the use of a key, or the like. When the shift control element is placed in this parking position, the switching lever 152 is turned via the shifting cable, and the switching disk 151 is placed in the locked position on the right, as shown in FIG. 27C. In this state, the drive pawl 155 is turned by the switching pawl 151b of the switching disk 151, and cannot be driven any longer. In addition, the stopping groove 151a and the stopping grooves 148a engage with each other, and the frame body 148 is linked to the case component 142 and locked via the switching disk 151. Consequently, the crank axle 131 is locked and the crank gear 135 does not rotate when an attempt is made to rotate the crank arms 133a and 133b in the forward direction. When, however, the crank arms 133a and 133b are caused to rotate in the backward direction, the drive pawl 149 disengages from the sun gear 147, and the crank axle 131 is able to rotate even if the frame body 148 has been locked. However, the rotation of the crank axle 131 is not transmitted to the crank gear. Consequently, the bicycle cannot be pedaled away in this locked state, making its theft less likely.
It is also possible for the switching disk to be energized by a suitable energizing means from the left side in FIG. 27, and for the switching disk and the frame body 148 to perform relative rotation in the locked position. In this case, the rotation is controlled, and sound is produced by relative rotation.
FIG. 28 depicts another embodiment, which is a modification of the third embodiment described above. In this embodiment, as with the third embodiment, a shift control element 9b is locked in the parking position by a key 181.
In FIG. 28, the shift control element 9b has a body unit 160b formed integrally with the right-side brake lever 16 and a control element 161 a rotatably mounted on the body unit 160b. The body unit 160b has a circular display component 162a for displaying a shift position or the parking position and a lock component 163a for maintaining the control element 161a in the parking position when this position has been reached. The display component 162a is rotatably supported on the body unit 160b, and is allowed to rotate in conjunction with the control element 161a. An indicator 165a for displaying [I] numbers indicating the four shift positions 1 through 4 drawn on the body unit 160b and [ii] a letter indicating parking position P is mounted on the surface of the display component 162a. The indicator 165a points to the parking position or to one of the shift positions (four operating positions).
As shown in FIGS. 29 and 30, the lock component 163a has a cylindrical lock 170a that can be rotated with the key 181, a lock member 172b that moves rectilinearly in conjunction with the cylindrical lock 170a, and a coil spring 173a for energizing the lock member 172b to the right in FIG. 29. The cylindrical lock 170a is used, for example, in a bicycle horseshoe-shaped lock, and contains in its interior a cylindrical component 170b rotatable by the key 181. This cylindrical component 170b can be rotated by the insertion of the key 181 between the first horizontal position shown in FIG. 28 and a second position (shown in FIG. 29) obtained by turning the key 90 degrees counterclockwise from the first position. A protruding pin 171a extends into the back surface (reverse surface in relation to the key-insertion surface) of the cylindrical component 170b of the cylindrical lock 170a.
The lock member 172b, which is a channel steel shape, is supported by the body unit 160b while allowed to move in the axial direction of the handle assembly. A slot 172c for stopping the protruding pin 171a of the cylindrical component 170b is formed in the lateral surface of the lock member 172b facing the cylindrical lock. Due to the stopping of the protruding pin 171a by the slot 172c, the lock member 172b is advanced to or retracted from [I] the forward position shown in FIG. 30A and [ii] the unlocking position shown in FIG. 30B (and reached by retraction from the forward position) by the rotation of the cylindrical component 170b between the first and second positions.
The coil spring 173a, which is stopped by a stopping tab 160c whose base portion is disposed on the body unit 160b and by a stopping tab 172d whose tip is disposed on the lock member 172b, energizes the lock member 172b in the direction of the control element 161a. The end face of the control element 161a that is opposite the body unit 160b is provided with a stopping groove 166a that faces the tip of the lock member 172b when the control element 161a has been moved to the parking position, and with a moving groove 167a that faces the tip of the lock member 172b when the shift positions of gears 1 to 4 have been reached. The stopping groove 166a has a C-shape to enable the tip of the lock member 172b to be stopped in accordance with the parking position, and the moving groove 167a has a fan shape in accordance with the shift positions of gears 1 to 4. A wall component 168a between the moving groove 167a and the stopping groove 166a presses against the tip of the lock member 172b in a normal riding state, and thus functions as a stopper for preventing the system from being switched from a shift position to the parking position or vice versa by the operation of the control element 161a.
The control element 161a is supported by the body unit 160b while allowed to be placed in five positions: four shift positions and a parking position. The operating positions can be changed by the grasping and rotation of the control element 161a with the thumb and the index finger. The control element 161a is linked to a cable winder (not shown) provided to the body unit 160b, and the inner cable of a shifting cable 180 whose tip is fixed to the cable winder is taken up or paid out by rotation. The tip of the inner cable of the shifting cable 180 is linked to the operator 78 of the internal shifting hub 10b (FIG. 24).
When the key 181 is inserted into the cylindrical lock 170a of the shift control element 9b, the coil spring 173a energizes the lock member 172b in the direction of the control element 161a, so the cylindrical component 170b is also placed in the first position (FIG. 30A). The result of this is that when the control element 161a is placed in one of the four shift positions, the tip of the lock member 172b protrudes into the moving groove 167a, and the control element 161a can be rotated solely among the shift positions of gears 1 to 4. When the control element 161a is in the parking position, the tip of the lock member 172b protrudes into the stopping groove 166a, and the control element 161a is locked in the parking position.
Inserting the key 181 into the cylindrical lock 170a turns the cylindrical component 170b 90 degrees from the first position to the second position (shown in FIG. 30B) when the system is moved from the parking position to a shift position or vice versa. As a result, the lock member 172b retracts in opposition to the energizing force of the coil spring 173a, and the tip of the lock member 172b disengages from the moving groove 167a or the stopping groove 166a. This arrangement allows the control element 161a to be rotated among the shift positions and the parking position. The control element 161a can therefore be moved from the parking position to a shift position or vice versa when, for example, the control element 161a is turned with the right hand while the key 181 is held in the left hand and the cylindrical component 170b is turned to the second position. When the force exerted by the left hand is released after the operation of the control element 161a has been completed, the lock member 172b is advanced by the energizing force of the coil spring 173a, and the cylindrical component 170b turns from the second position to the first position. The tip of the lock member 172b is thus stopped by the moving groove 167a or the stopping groove 166a, and the control element 161a is rotated solely among the four shift positions or is locked in the parking position.
The key 181 is removed from the cylindrical lock 170a in the normal riding state, and the key 181 is inserted into the cylindrical lock 170a (and the cylindrical component 170b is turned from the first position to the shift position) only when the bicycle is locked during parking or is unlocked at the start of riding. This arrangement makes it possible to retract the lock member 172b and to turn the control element 161a from a selected state to the parking state or vice versa. When the control element 161a is turned to the parking position, the operator 78 linked to an inner cable is rotated, the sleeve 77 is turned to the locked position PK in a corresponding manner, the rotation of the internal shifting hub 10b is controlled, and the hub shell 43 rotates and produces sound. As a result, theft can be impeded and bicycle theft prevented in the same manner as in the embodiments described above. In addition, this state is maintained when the control element 161a is placed in the parking position, making a return to a shift position impossible as long as the lock member 172b is not retracted by the cylindrical lock 170a. This impedes the unlocking of the antitheft device 85 in the antitheft position and makes theft less likely.
In addition, the key 181 is not used during riding and should be inserted into the cylindrical lock 170a solely during locking or unlocking, making it possible to keep this key in a key holder together with the bicycle lock key inserted into the lock during riding, and thus reducing the likelihood of the key 181 being lost.
While the above is a description of various embodiments of the present invention, further modifications may be employed without departing from the spirit and scope of the present invention. For example, the size, shape, location or orientation of the various components may be changed as desired. The functions of one element may be performed by two, and vice versa. In the embodiments described above, the antitheft device was provided to an internal shifting hub, a front hub, or a crank, but the present invention is not limited to these options alone, and the antitheft device may be provided to any component as long as this component can rotate during riding. Four-step gear shifters were used in the embodiments described above, but the gear shifter having a plurality of speed steps also encompasses continuously variable gear shifters. Thus, the scope of the invention should not be limited by the specific structures disclosed. Instead, the true scope of the invention should be determined by the following claims.
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A bicycle antitheft device includes an antitheft mechanism switchable between an antitheft state and a release state, wherein the antitheft mechanism includes a first member that moves relative to a second member to move the bicycle forward and backward. A movement controlling mechanism hinders the first member from moving relative to the second member when the antitheft mechanism is in the antitheft state, and a selection mechanism is provided for selecting one of the antitheft state and the release state. Alternatively, the antitheft mechanism may include a sound generator for generating a sound when the first member moves relative to the second member and the antitheft mechanism is in the antitheft state. The movement controlling mechanism and the sound generator may be combined into a single antitheft mechanism. The movement controlling mechanism and/or sound generator may be installed inside of an internal transmission such as a hub or crank transmission, or they could be installed inside a handlebar control for the transmission.
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This is a continuation of U.S. patent application Ser. No. 833,706, filed Feb. 11, 1992, now U.S. Pat. No. 5,166,760, issued Nov. 24, 1992, which is a continuation of U.S. patent application Ser. No. 660,872, filed Feb. 26, 1991, now U.S. Pat. No. 5,101,244 issued Mar. 31, 1992.
BACKGROUND OF THE INVENTION
The present invention relates to a high-speed diode having a small reverse recovery current and a device produced by application of the diode. In particular, it relates to a semiconductor device and a method of producing the same, in which it is possible to make a diode high in withstanding voltage, high in reliability and simple in manufacturing.
FIG. 9 shows current and voltage waveforms of a general diode in which the state thereof changes from a current conductive state in the forward direction (hereinafter referred to as "forward current-conductive state") into a current blocking state in the reverse direction (hereinafter referred to as "reverse current-blocking state"). When a current with a current density J F is passed in the forward direction and then a voltage V R is instantaneously applied in the reverse direction, a reverse recovery current flows. It is necessary to reduce the peak value of the reverse recovery current density J RP at this time to be as small as possible, because a power loss is generated proportionally to the peak value of the current density J RP . Furthermore, the peak value of the current density J RP acting as a noise source becomes a cause of a faulty operation in a circuit using the diode, in particular, an integrated circuit using the diode. From this point of view, a diode structure for reducing the current density J RP as shown in FIG. 10 has been discussed in the papers of IEEE International Electron Devices Meeting, pages 658-661, 1987. In this structure, a p layer 113 separated into parts is formed in an n - layer 112 which is formed on one surface of an n + substrate 111 by a technique such as a crystal growing technique. An electrode 121 is disposed so as to be in ohmic contact with the p layer 113 and forms a Schottky junction with exposed portions of the n - layer 113 where the p layer 113 is not formed, that is, exposed portions of the n - layer 112 which are respectively disposed between the separation parts of the p layer 113. The electrode 121 is formed so as to extend onto an oxidized film 131 in the peripheral portions thereof, so that the electrode 121 serves as a field plate for relaxing the electric field in the peripheral portions thereof. An opposite electrode 122 is disposed so as to be in low ohmic contact with the n + layer 111. When a current is passed through the diode from the electrode 121 to the electrode 122, holes are injected through the pn junction portions, that is, from the p layer 113 to the n - layer 112, so that excess carriers are accumulated in the n - layer 112. However, only a very small number of holes are injected through the Schottky junction portions from the electrode 121 to the n - layer 112. Accordingly, the concentration of carriers accumulated in the vicinity of the interface between the pn junction and the Schottky junction is reduced compared with the conventional diode having only pn junctions. Consequently, as is obvious from FIG. 9, the diode of FIG. 10 has an advantage in that it is effective for reduction of the current densit J RP , because the current density J RP at the instance when the reverse bias V R is applied is produced by the carriers accumulated in the vicinity of the pn junctions. Furthermore, in a reverse current-blocking state, because a depletion layer extending from the pn junctions which are formed between the p layer 113 and the n - layer 112 and disposed on the both sides of the Schottky junction reaches through under the Schottky junction so that the electric field applied to the Schottky junction can be relaxed. Accordingly, the diode has another advantage in that a leakage current can be reduced compared with the conventional diode having only Schottky junctions.
On the other hand, a diode structure for reducing the current density J RP as shown in FIG. 11 has been disclosed in Japanese Patent Unexamined Publication No. Sho-58-60577. The diode of FIG. 11 is different from the diode of FIG. 10 in that a p layer 114 having a carrier concentration lower than that of the p + layer 113 is provided on the exposed surface portions of the n - layer 112 which are located between separated parts of the p + layer 113. The electrode is disposed so as to be in ohmic contact with the p + layer 114. Accordingly, because a current is mainly passed through the pn junctions between the p layer 114 and the n - layer 112 which is small in diffused potential when the diode is in a forward current-conductive state, the diode has an advantage in that a forward voltage drop can be reduced compared with the diode having only the pn junctions between the p + layer 113 and the n - layer 112. Furthermore, because the carrier concentration in the p layer 114 is low, the quantity of carriers injected from the player 114 can be reduced. Accordingly, the diode has another advantage in that the current density J RP can be reduced. Furthermore, because a metal-semiconductor interface such as a Schottky junction is not used, the diode is little affected by factors such as contamination at the semiconductor surface. Accordingly, the diode has a further advantage in that the diode has stable characteristics. Of course, the diode of FIG. 11 has the same effect as the diode of FIG. 10 in that the electric field applied to the pn junctions between the p layer 114 and the n - layer 112 can be relaxed by the depletion layer extending from both the deep p + layer 113 and the n - layer 112 to thereby reduce a leakage current.
SUMMARY OF THE INVENTION
The diode as shown in FIG. 10 has a problem in that, by the bonding of a wire 141 to the electrode 121, a leakage current is increased to deteriorate the withstanding voltage. The cause of this problem is conjectured as follows.
When the wire 141 is bonded to the electrode 121, a defect may be produced in an interface between the electrode 121 and the n - layer 112 by the pressure applied to the electrode 121 and the wire 141. Because the defect forms a recombination center, electrons in a conduction band flow into the defect so that a leakage current increases. In particular, because the thickness of the Schottky barrier decreases as the strength of the electric field applied to the interface between the electrode 121 and the n - layer 112 increases in a reverse bias state, the probability that electrons transit into the recombination center in the form of a tunnel current increases. It happens therefore that the leakage current increases remarkably and, accordingly, the withstanding voltage deteriorates.
On the other hand, the diode as shown in FIG. 11 has a problem in that the current density J PR becomes larger than that of the diode of FIG. 10 because there exists carrier injection from the p layer 114. Although it is possible to reduce the carrier concentration in the p layer 114 to thereby reduce the current density J PR , it has a disadvantage in that the withstanding voltage deteriorates when the carrier concentration of the p layer 114 is too small. The presumed cause of the disadvantage is as follows. When the carrier concentration in the p layer 114 is too small, a depletion layer is punched through the electrode 121 so that the withstanding voltage deteriorates. The diode of FIG. 11 has another problem in that the steps of the producing process for forming the p layer 114 are increased in number compared with the diode of FIG. 10.
As described above, because there is no consideration in the prior art upon the deterioration of the withstanding voltage in a structure to attain a small current density J RP , a problem arises in that reduction of the current density J RP is incompatible with security of the withstanding voltage.
An object of the present invention is therefore to provide a semiconductor device which has a small current density J RP and a stable withstanding voltage, which can be produced easily, and which is excellent in stability, as well as to provide a method of producing the same.
To attain the foregoing object, the semiconductor device according to the present invention has a feature that a first diode having a pn junction and a second diode having a combination of a Schottky barrier and a pn junction in a current-conductive direction are arranged in a direction perpendicular to the current-conductive direction. More specifically, the feature is in that when a forward current with a current density J F is passed into the second diode, the relation ##EQU1## is established in a forward voltage V F range of 0.1 (V) to 0.3 (V), where k represents the Boltzmann constant (≈1.38×10 -23 J/K), T represents the absolute temperature, and q represents the quantity of electron charges (≈1.6×10 -19 C) As a specific example of the configuration thereof, the first diode is constituted by a first semiconductor region of one conductive type and a second semiconductor region of the other conductive type which is provided so as to be adjacent to the first semiconductor region to form a pn junction therebetween, so as to be in ohmic contact with one main electrode, and so as to have an impurity concentration higher than that of the first semiconductor region, and the second diode is constituted by the first semiconductor region of the one conductive type and a third semiconductor region of the other conductive type which is provided so as to be adjacent to the first semiconductor region to form a pn junction therebetween, so as to be in contact through a Schottky barrier with the one main electrode, and so as to have an impurity concentration higher than that of the first semiconductor region. In this case, it is preferable that the third semiconductor region has the carrier concentration of not larger than 1×10 14 cm -2 and has a thickness of not larger than 10 nm. As a whole configuration of the semiconductor device, it is ideal that the second diodes are enclosed by the first diodes respectively.
Furthermore, in order to attain the foregoing object, the method of producing a semiconductor device according to the present invention comprises: a first step of forming, on one main surface of a first semiconductor region of one conductive type, a second semiconductor region of the other conductive type to extend from the one main surface into the inside of the first semiconductor region so as to have a plurality of small areas and an annular area surrounding the small areas when seen from the one main surface and so as to have an impurity concentration higher than the first semiconductor region; a second step of forming, on the one main surface, a metal layer containing impurities of the other conductive type on the second semiconductor region and portions of the first semiconductor region which are exposed among the small and annular areas of the second semiconductor region; and a third step of bringing the metal metallic layer into ohmic contact with the second semiconductor region and diffusing impurities of the metal layer into the first semiconductor region to form a third semiconductor region of the other conductive type which is thinner than the second semiconductor region, and performing a heat treatment so as to form a Schottky barrier between the metallic layer and the third semiconductor region.
Preferably, the above-mentioned metal layer is constituted by a material containing aluminum as a main component, and the heat treatment in the above-mentioned third step of carried out at a temperature in a range of 430 to 577° C.
In the present invention, a pn junction is formed under a Schottky barrier. Accordingly, because the pn junction can prevent the increase of a leakage current caused by a tunnel current or the like even when a defect at wire bonding or the like arises in a Schottky barrier interface, the withstanding voltage can be prevented from lowering.
Furthermore, because the injection of holes into the n - layer from the p layer under the Schottky barrier can be suppressed by establishing the value of n to be a range of 1.00≦n≦1.15, the excess carriers accumulated on the pn junction interface can be reduced and, accordingly, the reverse recovery current density J RP can be reduced.
Furthermore, because a p layer can be formed under the Schottky barrier by making an electrode contain p-type impurities and diffusing the p-type impurities into a semiconductor, there is no necessity of providing a new process for forming a p layer by ion implantation or other technique and, accordingly, the production is made easy.
In the semiconductor device according to the invention, not only a reverse recovery current can be reduced to prevent the deterioration of the withstanding voltage but also the producing process can be simplified. Consequently, there arise effects of the reduction of noises, the improvement of reliability, the facilitation of production, etc.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1A and 1B are a sectional view and a plan view of a semiconductor device as an embodiment of the present invention;
FIGS. 2A and 2B and FIG. 3 are explanatory views for explaining the effect of the invention;
FIGS. 4A through 4C are sectional views showing a method for producing a semiconductor device according to the invention;
FIG. 5 is an explanatory view showing a producing condition according to the invention;
FIGS. 6A, 6B, 7 and 8 are sectional views and a circuit diagram showing applications of the invention;
FIG. 9 is an explanatory view for explaining the reverse recovery characteristic of a diode; and
FIGS. 10 and 11 are sectional views of conventional semiconductor devices.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to the drawings illustrating embodiments of the invention, the present invention will be described in detail hereunder.
FIGS. 1A and 1B are a sectional view and a plan view of an embodiment 6 of the semiconductor device according to the present invention. In FIGS. 1A and 1B, the reference numeral 1 designates a semiconductor substrate having a pair of main surfaces 11 and 12 disposed in opposition to each other. The semiconductor substrate 1 is composed of an n + layer 13 disposed so as to be adjacent to one main surface 11, an n - layer 14 disposed so as to be adjacent to both the n + layer 13 and the other main surface 12 and having an impurity concentration lower than that of the n + layer 13, a p layer 15 extending from a plurality of selected portions of the other main surface 12 into the inside of the n - layer 14 and having an impurity concentration higher than that of the n - layer 14, and a p layer 16 extending from the other main surface 12 into the inside of the n - layer 14 so as to be located between separated portions of the p layer 15 and having an impurity concentration higher than that of the n - layer 14 and having a depth thinner than that of the p layer 15. The p layer 15 is composed of a plurality of small areas 151, and an annular area 152 for surrounding the small areas 151. The reference numeral 2 designates one main electrode which is provided so as to be in ohmic contact with the n + layer 13 at the one main surface 11, 3 designates the other main electrode which is provided so as to be in ohmic contact with the p layer 15 at the other main surface 12 and which forms a Schottky barrier between the other main electrode 3 and the p layer 16, and 4 designates an oxidized film formed so as to partially cover the n - layer 14 and the p layer 15 in the peripheral portions of the other main surface 12. The other main electrode 3 extends so as to partially cover the oxidized film 4. Thus, between the main surfaces 11 and 12 in pair, there is provided a diode structure composed of a first diode which is constituted by the n + layer 13, the n - layer 14 and the p layer 15, and a second diode which is constituted by the n + layer 13, the n - layer 14, the p layer 16 and the Schottky barrier.
The embodiment of the present invention as illustrated in FIGS. 1A and 1B is different from the conventional example shown in FIG. 11 in that a Schottky barrier is provided between the p layer 16 and the main electrode 3. The effect of the invention will be described with reference to FIGS. 2A and 2B. The diagram of FIG. 2A shows the energy band structure of a Schottky barrier region formed between the electrode 121 and the n - layer 112 in the conventional example of FIG. 10. The diagram of FIG. 2B shows the energy band structure of a Schottky barrier region formed between the main electrode 3, the p layer 16 and the n - layer 14 in the invention of FIG. 1A. In the conventional structure shown in the diagram of FIG. 2A, it is supposed that when a defect is produced in the Schottky barrier interface by wire bonding or the like as described previously, electrons in a conduction band in a reverse bias state flow into the recombination center produced by the defect to thereby increase a leakage current and, accordingly, the withstanding voltage deteriorates. In the embodiment of the present invention shown in diagram of FIG. 2B, on the other hand, the probability that electrons in a conduction band transit into the defect in the form of a tunnel current can be remarkably reduced even when a defect is produced in the Schottky barrier interface because the width W of the barrier is enlarged by the p layer 16. When, for example, the width of the p layer 16 exceeds 100 Å, there is little transition of electrons by tunneling effect. Accordingly, the leakage current is reduced to attain an improvement in the withstanding voltage. Furthermore, because a Schottky barrier is formed between the p layer 16 and the main electrode 3, the invention has an advantage in that the deterioration of the withstanding voltage as in the conventional diode of FIG. 11 is prevented even when the depletion layer caused by the pn junction is punched through to the main electrode 3. Further, the height φ Bn of the barrier against electrons, being innate in metal, can be increased by Δφ Bn by the p layer 16. Accordingly, the leakage current flowing over the barrier (φ Bn +Δφ Bn ) in a reverse current blocking state can be also reduced. For example, the leakage current at 150° C. can be reduced by about the order of one figure by increasing the Δφ Bn by 0.1 eV. Because the P layer 15 is formed more deeply than the p layer 16, it is a matter of course that there arises an effect that the electric field applied to the pn junction of the p layer 15 can be relaxed by the depletion layer extending from the pn junctions of the p layer 15. Further, the supply of holes into the p layer 16 can be suppressed by the barrier φ BP against holes in the p-type Schottky barrier. As described previously, in the diode of FIG. 11 in which the p layer 114 is in ohmic contact with the electrode 121, holes are supplied from the electrode 121 to the p layer 114 and then injected from the p layer 114 into the n - layer 112. On the contrary, in the diode 1 of FIGS. 1A and 1B, the supply of holes to the p layer 16 is suppressed by φ BP , so that the injection of holes from the p layer 16 into the n - layer can be reduced. As a result, carriers accumulated in the vicinity of the pn junctions can be reduced, so that the current density J RP can be reduced. In the more preferred p layer 16, the current density J RP can be reduced more remarkably because the injection of holes can be reduced extremely be depleting the p layer on the basis of built-in potentials both the pn junction and the Schottky junction.
In addition, because the p layer 15 and the n - layer 14 are more biased in the forward direction by the increase Δφ Bn of the height of the barrier due to the p layer 16, there arises an effect that the forward voltage drop can be reduced. That is, as described previously, in the diagram of FIG. 2A, electrons injected from the n + layer 13 are mainly passed through the Schottky junction to make it difficult to promote the injection of holes from the p layer efficiently. On the contrary, in the diagram of FIG. 2B, the p layer 15 and the n - layer 14 are more biased in the forward direction by the higher voltage corresponding the value Δφ Bn to thereby increase the quantity of hole injection from the p layer 15, so that the forward voltage drop in the diode can be reduced.
FIG. 3 shows a result of an experiment in which the electrical characteristic of the diode has been examined in detail at a room temperature in the case where various types of p layers 16 are applied to the diode 1 of FIG. 1. The graph of FIG. 3 shows the relationship between the value of n (the axis of abscissas) expressed by the formula ##EQU2## and the value of J RP /JF which is a ratio of a reverse recovery current density to a forward current density (the axis of ordinates) in a region in which a linear relationship exists between the value of a forward voltage V F which is in a range of about 0.1 to about 0.3 V and the value of lnJ F when a current with the current density J F is made to flow through the diode in the forward direction. The relationship shown in the graph of FIG. 3 shows that the majority carriers occupy the main current as the value of n approaches to 1, and that the current used for recombination with injected minority carriers becomes large as the value of n approaches to 2. As a result of examination of the ratio J RP /J F of the reverse recovery current density J RP to the forward current density J F , it has been found that the relationship of FIG. 3 is established. It has been found that the ratio J RP /J F can be reduced by establishing the value of n to be in a range of 1.00 to 1.15. This shows that the reverse recovery current density J RP can be reduced by reducing the injection of the minority carriers (that is, by reducing the value of n) even when the p layer 16 is provided.
In respect to the condition for the p layer 16, it is preferable that the quantity of injected ions is not larger than about 1×10 14 cm in the case where the p layer 16 is formed by implantation of B (boron) ions. If the quantity of injected ions is larger than 1×10 14 cm -2 , the relation between the p layer 16 and the main electrode 2 approaches to ohmic contact and, at the same time, the concentration of the p layer 16 increases, so that holes are injected easily from the p layer 16 into the n - layer to thereby increase the reverse recovery current density J RP .
FIGS. 4A through 4C show a method of producing a semiconductor device as a preferred embodiment of the present invention. First, an n - layer 14 having a specific resistance and a thickness necessary for attaining desired a withstanding voltage is prepared. From one surface of the n - layer 14, p-type impurities are partially introduced by ion implantation or diffusion. Here, the p-type impurities are diffused by a heat treatment to a desired depth, for example, 1 to 10 μm in the case of a diode of 600V, thereby forming a p layer 15 (FIG. 4A). Then, an electrode 3 containing p-type impurities is piled on the surface of the p layer 15 and the surface of the n - layer 14 enclosed by the p layer 15 (FIG. 4B). Here, the p-type impurities in the electrode 3 are diffused into the surface of the n - layer 14 by a heat treatment, thereby forming a p layer 16 (FIG. 4C). By applying the aforementioned technique, it is possible to omit the step of forming the p layer 16 by using such as ion implantation which was necessary in the conventional case of FIG. 11. In this case, because the junction depth of the p layer 16 is very small, that is, not larger than about 100 nm, it is preferable that the final end p layer 15 is connected to the other final end p layer 16 for the double purpose of relaxing the electric field in the periphery and securing the withstanding voltage. In the case where any suitable shape in plan, for example, a stripe shape, a circular shape, a polygonal shape, may be used as the shape of the p layer 15, the effect of the invention can be attained. It is a matter of course that the electrode for forming a Schottky barrier and the electrode for forming an ohmic junction may be formed of different materials and may be short-circuited electrically with each other.
FIG. 5 shows a result of an experiment for examination of a more preferred example of the electrode 3 in the case where a material containing aluminum is used for the electrode 3. As an experimental result by the inventors, it has been found that the p layer 14 is formed when the temperature for the heat treatment is higher than 430° C. However, if the temperature is made to be not lower than 577° C. which is an eutectic point for aluminum and silicon, there occur both wire breaking in the electrode 3 and unevenness in the p layer 14 caused by condensation of aluminum. Accordingly, it is not preferable that the temperature for the heat treatment is made to be equal to or higher than the eutectic point. From the result, there arises an effect the silicon-containing aluminum widely used in the semiconductor process can be applied to the electrode 3 and can be applied to the semiconductor producing process. In the case where the amount of silicon added to aluminum is small, that is, in a range of 2 to 3%, the barrier height may be reduced to about 0.79 eV by elution of silicone in a silicon wafer at 550° C. but the barrier height can be increased by 0.1 eV to thereby reduce the leakage current by the order of about one figure compared with the barrier height of 0.69 eV in the case where no pn junction is provided. In this case, the barrier height of Schottky junction annealed at 430-500° C. is about 0.89 eV, 0.1 eV higher than that at 550° C. the leakage current for the 0.89 eV device is still one figure lower than that for the 0.79 eV device.
FIGS. 6A and 6B show applications of the present invention in which a power MOSFET and the semiconductor device according to the invention are used in combination. The power MOSFET is composed of a p-type well layer 17 formed in the n - layer 14, an n-type source layer 18 formed in the inside of the well layer 17, an gate electrode 4, and drain and source electrodes formed by extending the electrodes 2 and 3. The reference numeral 6 designates a bonding wire for providing the diode on the electrode 3. As a result, a main current can be passed into the power MOSFET through the built-in diode composed of an n + layer 13, an n + layer 14, a p layer 15 and another p layer 16, so that not only the deterioration of the withstanding voltage caused by the bonding of the wire 6 can be prevented but also the reverse recovery current density J RP can be reduced. Further, as shown in FIG. 6B, the semiconductor device according to the present invention may be provided in the electrically conductive region of the power MOSFET. Accordingly, the present invention can be applied to the electrically conductive region occupying a large area in the power MOSFET to form a composite device so that a larger diode current can be taken out. It is a matter of course that the diode according to the present invention may be applied to another transistor having an n + substrate such as a bipolar transistor to form a composite device.
FIG. 7 shows an example in which the present invention is applied to a dielectric isolated substrate 7 used in power ICs and the like. The diode according to the present invention is formed in the inside of a single crystal island 73 formed through an insulating film 72 in a substrate of a multicrystal semiconductor 71. The electrodes 2 and 3 are exposed at one and the same surface. By applying the semiconductor device according to the present invention to a power IC using the dielectric separating substrate, not only a bonding pad can be provided on the electrode 3 but also the reverse recovery current density J RP can be reduced without spoiling the characteristics of other elements of a power IC. Furthermore, because the p layer 16 can be constituted by an electrode containing aluminum as a main component, there is no necessity of addition of a new process.
FIG. 8 shows an example in which the present invention is applied to a feedback diode D F included in a transistor module. The circuit shown in FIG. 8 is a three-phase inverter module using IGBT (integrated gate bipolar transistor). In particular, in the module using IGBT which is remarkably improved in high-speed switching, the turning-on speed thereof is so high that when an IGBT connected to an E terminal turns on, a diode D F connected to a C terminal just above the IGBT is biased reversely so that a reverse recovery current J RP is generated. There arises a disadvantage, therefore, in that the reverse recovery current acts as a noise source to make a gate circuit of an off-state parallel-connected IGBT maloperate to thereby turn on the IGBT. As a result, the C and E terminals are short-circuited, so that the IGBT may be destroyed in the worst case. When the diode according to the invention is applied to the module, the reverse recovery current J RP is so small that not only noise generation can be suppressed to prevent the maloperation of the circuit but also a defect in the withstanding voltage, of the diode requiring a large number of bondings in the module can be reduced to improve the yield thereof.
It is a matter of course that the same effect can be attained in the case the lifetime of the minority of carriers in the semiconductor device according to the present invention may be shortened by a technique such as radiation of electron rays or in the case where the p-type and n-type semiconductor layers in the semiconductor device according to the invention may be replaced by each other.
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A semiconductor device includes a diode having a Schottky barrier and a MOS transistor integrally formed in one and the same semiconductor substrate in which the diode and MOS transistor have their main electrode in common use. The diode has a first diode portion having a pn junction in a current-passing direction and a second diode portion having a combination of the Schottky barrier and another pn junction in the current passing direction.
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TECHNICAL FIELD
This invention relates to large diameter flexible pipes of for drilling and oil production, which are able to withstand high pressure while maintaining great flexibility.
STATE OF THE ART
In oil field production, flexible pipes are used in various applications such as the pipeline. A flexible pipe is herein defined as a pipe which during its transport and its installation is sufficiently flexible along its longitudinal axis to accept a minimum radius of curvature of at least 10 times smaller than that of the rigid tube of the same dimensions. These flexible pipes must be able to withstand high internal pressures that can reach 5,000 to 10,000 psi (35 MPa to 70 MPa). In underwater production utilisation, they must support collapse due to external pressures as well as tension loads during their installation.
Patent EP 871,831 describes a monolithic flexible device comprising a single metallic tubular structure associated to sealed means containing the transported fluid through this tubular structure. The tubular structure is comprised of at least two sets of slits extending along the wall to provide flexibility. Each slit extend in a substantially circumferential direction on an arc smaller than 180°. The space between the set of slits defines at least two tension bands that extend along the tubular structure of the pipe. The set of slits and the bands extend along helix. The arches generated by the slits are also on helixes, but in the opposite direction with a greater helix angle with regard to the axis of the flexible pipe.
The monolithic flexible pipes gain in simplicity compared to the other flexible devices of large diameter available based on the cable technique but the presence of the two bands of tension diametrically opposed on the same monolithic tubular structure generates important plastic deformations in the small pitch arches which links the tension bands in particular when reeled and unreeled for transportation and installation This is due to the small length of these arches, which from the design of the monolithic flexible device cannot exceed a half circumference. Use of this flexible pipe is thus limited to few cycles of reeling/unreeling and must thus be kept to applications known as static where there are none or few alternatives bending in service. The piping interconnexion between oil production components on the seafloor illustrates a static or quasi-static example of flexible pipes where the flexible capability of the pipe is needed only to facilitate its transport, its installation and connections on the seafloor.
Nevertheless, there are needs in particular in riser and the links between the seafloor and the surface where a flexible pipe must be able to support alternate flexion during service that can exceed 15 years. It is thus desirable to improve the monolithic tubular structure described in the patent EP 871,831 to give it acceptable fatigue performances when subject to alternative flexing.
SUMMARY OF THE INVENTION
The object of the invention is to provide a pipe for the fluid transport with a flexibility in the elastic range of the component's material that is greatly improved in order to be able to support alternative flexing while subject to high pressures.
The object of the invention is thus a multi-structure pipe intended to transport a fluid, used, in particular in oil production, including an assembly of tubular structures concentric to the pipe axis and means to contain the transported fluid, the assembly of tubular structures including a first hollow and closed structure having a set of substantially circumferential slits, each slit extending on an arc of more than 180° and defining a tension band extending with a helix shape along the first tubular structure, and at least a second tubular structure having also at least a tension band also with a helix shape of same direction and same pitch that the tension band of the first tubular structure, and the tension bands of the first and second tubular structure are maintained to a fix distance from one another by support between the second tension band on the first tubular structure to provide the capacity in tension of the pipe.
According to a first embodiment of the invention, the flexible pipe is comprised of two concentric tubular structures with slits and the means to contain the transported fluid is a sealed envelope located between the two tubular structures. This sealed envelope can be a metal pipe with a corrugated wall located between the two tubular structures with slits.
According to a second embodiment, the external structure is a tension band, which could be comprised, of several wires on which a low pitch winded tubular structure provides a burst resistance of the flexible pipe.
Last of all according to a third embodiment, the external structure is only a tension band and the means to contain the fluid is located inside the first internal tubular structure. The means to seal is obtained by a thin metal pipe corrugated in helix which can be reinforced for higher external pressure by a carcass of reinforcing profiled wire inserted inside the inside helix groove formed by the corrugations.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a perspective view illustrating a flexible portion of pipe constructed in accordance to a first embodiment of the invention.
FIG. 2 is a sectional view of the flexible pipe of FIG. 1 .
FIG. 3 is a perspective view of a flexible pipe according to a second embodiment of the invention.
FIG. 4 is a sectional view of a flexible pipe according to a third embodiment of the invention.
FIG. 5 is a perspective view illustrating a flexible pipe shown in a sectional view on FIG. 4
DETAILED DESCRIPTION OF THE INVENTION
While referring to FIG. 1 , the flexible pipe 1 A has a first internal tubular structure 3 made from a monolithic metal pipe. The tubular structure 3 is cylindrical and comprises a set of parallel slits 5 . Each slit 5 has a circumferential length defined by a first end 5 a and another opposed end 5 b. The length extends substantially more than 180° and preferably between 200° and 300°. The set of slits 5 defines a band 7 that is solid with no slit 5 . This band 7 forms a helix with high pitch and small angle of about 10 to 30°. The width of the band 7 is uniform and constant along the central portion of the tubular structure 3 . The width of the band 7 extends out on 25 to 45% of the circumference whereas the width of the set of slits 5 covers the remaining portion of the circumference. Arches 9 delimited by slits 5 are preferably on parallel helixes with opposite direction of the helix of band 7 . The helix pitch of the arches is low with an angle preferably ranging between 70 and 85°.
In the illustrated embodiment, a sealed envelope 4 surrounds the internal tubular structure 3 . This envelope 4 can be made by continuous extrusion of a polymer pipe. An external tubular structure 2 made also from of a monolithic metal tube surrounds the sealed envelope 4 . The tubular structure 3 is cylindrical and also comprises a set of parallel slits 5 . Each arch 8 also has a circumferential length defined by a first end 8 a and another opposed end 8 b . The length extends also substantially more than 180° and preferably between 200° and 300°. The ends of arches 8 are linked by a tension band 6 that is solid and has no slits 5 . This band 6 forms a high pitch helix parallel and of same angle that band 7 . As band 7 , the width of the band 6 is uniform and constant along the tubular structure 2 . The width of the band 7 also covers 25 to 45% of the circumference whereas the width of the set of slits 5 covers the portion of remaining circumference. This width can be different to the width of the tubular structure 3 but preferably the band 6 section measured on a transversal section to the tubular structure 2 must be substantially equal to the band 7 section measured on a transversal section to the tubular structure 3 .
One thus obtains a flexible pipe 1 able to withstand compression or tension loads along its longitudinal axis 1 ′ by interaction of the tension bands 6 and 7 between themselves. Indeed, on FIG. 2 one notes that the tension bands 7 and 6 that have parallel helix are diametrically opposed in order to compensate for the imbalance induced in first tubular structure 3 by the offset of tension band 7 . When the flexible pipe 1 is subjected to a tension, this interaction is carried out by contact through the sealed envelope 4 of the interior face 6 a of the tension band 6 of the external tubular structure 2 on the arches 9 of the internal tubular structure 3 which are connected to the tension band of tension 7 of the internal tubular structure 3 . When the tube is subjected to compression, it is then the outside 7 b of the tension band 7 that enters in contact with the arches 8 , through the sealed envelope 4 , which are connected to the tension band 7 of the internal tubular structure 3 . One notes as well as the tension bands 6 and 7 are free to move from one another longitudinally, which gives its flexibility to pipe 1 but are able to maintain a radial interaction in order to avoid a crushing of the tubular structure under simple tension or the buckling of this one when the flexible pipe is subjected to compression. Due to the location of the sealed envelope 4 between the two tubular structures 2 and 3 , this envelope is supported on arches 8 when it is subjected to a fluid internal pressure and is supported on arches 9 when it is subjected to a fluid external pressure.
On FIG. 3 , a second embodiment of the invention is shown. This embodiment is preferred in the case the flexible pipe, according to the invention, will be subjected to very high tension as in the case of flexodrilling drill string. The flexible pipe 10 includes a first tubular structure 12 that comprises a tension band 11 and arches 17 of opposed direction helixes with high and small pitch as for the tubular structure 3 . The originality comes from the fact that the tension band 11 is thick in order to be able to support a strong tension although it is of a small diameter. As in the first embodiment, one finds a sealed envelope 14 that is preferably of metal impermeable to fluid and features a corrugated wall 18 . Corrugations 18 are preferably on helixes with multiple starts. The external tubular structure is substantially different from the one on the first embodiment of the invention, due to the fact that it does not comprise a monolithic tubular structure. In fact, this one comprises one or more metal wires 13 a, b, c having a total section 13 which will be balanced with section 11 of the tension band of internal tubular structure 12 as it has been previously explained. This tension band 13 is combined with a rectangular wire winding 15 wrapping the tubular structure with the same helix direction that arches 17 of the internal tubular structure 12 . These wires 15 can be either metal or high performance reinforcing fibbers (glass, aramid, carbon) in a hollow metal envelope. These wires can be connected between themselves and possibly to the tension band 13 at the location 16 .
Thus, one obtains a tubular structure with high performance easy to produce, on continuous line, by winding and welding the edges of a sealing band 14 with a very high pitch on the internal tubular structure 12 , then winding the tension band(s) 13 with the same high pitch with the same direction as the tension band 11 followed at last by the winding of the wire mesh 15 resistant in hoop with small pitch and in the opposite direction of the tension band 11 . Since the configuration of the sealed envelope 14 again between the two tubular structures 12 and 13 - 15 , this envelope is supported by the winding of wire 15 when subjected to a fluid internal pressure and is supported on the arches 17 of the internal tubular structure 12 when subjected to a fluid external pressure.
FIGS. 4 and 5 illustrate a third embodiment of the invention, which will be preferred for, cost saving reasons when external pressure or compression services are low. Nevertheless, one finds the first monolithic tubular structure 22 with its single tension band 21 and its arches 27 . On the other hand, the sealed envelope, preferably out of corrugated thin pipe 24 is laid out inside the first tubular structure 22 . This makes it possible to use arches 27 to resist the external pressure and to avoid having to wind another structural mesh to take care of this as per the two preceding embodiments. It is now necessary to have only one or more tension band(s) 23 to balance the flexible pipe. To avoid lateral displacement of the tension band 23 when sliding, stops 28 are located on arches 27 of the first tubular structure. An outer jacket 29 is installed to isolate the tubular structure from the external environment.
To improve the resistance in external pressure of the corrugated thin metal envelope 24 , a reinforcing helix shaped wire 25 can be inserted inside the helix fold formed by the corrugations.
The invention offers significant improvements for the tubular structure of flexible pipes. The first tubular structure is monolithic but is comprised only of a single tens ion band in order to give maximum flexibility to the arches, which closes the tubular structure around this tension band. This tubular structure, being unbalanced from the radial offset of the single tension band, is rebalanced by the winding of one or more wires with the same pitch and same direction as the tension band of the monolithic tubular structure making contact with the arches directly or indirectly of the monolithic tubular structure to be able to withstand substantial tension loads.
It is also possible to seal the first tubular structure by vulcanising an elastomer in the slits. In this case the slits can have a no rectilinear form to increase the surface of contact and thus the width of shearing of the elastomer.
One can also form the first tubular structure by welding in spiral a thick band comprising slits of which the length is smaller than the width of the band laid out substantially perpendicular to the direction of the band. In this case it is advantageous to carry out the sealing by welding on the two edges, a corrugated thin sheet band having corrugation on a length smaller than the width of the band covering the slits area, on the thick band.
Finally one can conceive to carry out the first tubular structure by welding in spiral a single band on which corrugation folds have been formed by stamping directly the thick band and pushing the material along lines substantially perpendicular to the direction of the band but without going through the band.
Whereas this invention was illustrated by the three embodiments, it will appear to the man skilled in the art that it is not thus limited, but is likely to accept variations within the extent of the protection conferred by the claims.
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A multi-structure pipe intended to transport a fluid, used in particular in oil production, including a first hollow and closed tubular structure having a set of substantially circumferential slits, each slit extending on an arc of more than 180° and defining a tension band extending with a helix shape along the said first tubular structure, and at least a second tubular structure having also at least a tension band also in helix shape of the same direction and pitch as the first tubular structure, and the tension bands of the first and second tubular structure being maintained at a fix distance from one another by support of the second tension band on the first tubular structure to provide the tension capacity of the pipe.
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CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of U.S. Provisional Application Ser. No. 60/694,401, filed Jun. 27, 2005, the entire contents of which are hereby incorporated herein by this reference.
BACKGROUND
[0002] Intravenous fluids are administered in almost all situations where invasive procedures are performed, where patients require repeated doses of injectable medications, where fluids or blood products are administered, and where a variety of tests are performed, as well as elsewhere. In order to regulate the volume of intravenous fluids that flow into a patient over a given period of time, thumb-wheel compression regulators are universally used. These thumb-wheel regulators (TWR) are manufactured in all intravenous fluid system tubing sold in the United States. Though the TWR is effective in controlling the rate of fluid infusion, it also acts as a restrictor when fluids need to be given rapidly. Though the TWR may be dialed “open” during this period, it may be cumbersome, especially when only an acute “bolus” of fluid is required, e.g., fluid used to flush an emergency drug into the patient.
[0003] Standard intravenous lines typically include: a) a proximal “spike and drip chamber” which is used to puncture a latex (or latex like) diaphragm on an intravenous fluid bag or bottle, or on a medication bottle, b) a length of PVC tubing, c) a TWR which is used to regulated the flow of fluid from the raised bag or bottle, and d) a distal connector which may be attached to a compatible intravenous catheter, or other components.
[0004] These systems allow the administration of fluids and drugs at a relative rate. The rate of fluid flow will depend on a) the height of the intravenous bag or bottle above the patient (e.g., gravity dependent), b) the set point of the TWR, c) the internal diameter of the intravenous catheter and d) resistance at the catheter-patient interface. Maximal flow will occur with the intravenous bag or bottle raised as high as the tubing and extension tubing will allow, a completely disengaged TWR, a large diameter intravenous catheter and a zero resistance catheter-patient interface.
[0005] Because of the limit of the length of tubing, the availability of large veins to accept large diameter catheters and non-zero resistance at the catheter-patient interface as flow through these systems may be slow. When flow is too rapid, the TWR is used to apply a restriction to flow.
[0006] When a drug must be delivered to the patient via the intravenous system, it is typically injected into an intravenous port or at the three-way stop cock. Once within the intravenous line, the rate of fluid flow of fluids from the intravenous bag or bottle will determine how rapidly the medication reaches the patient. This rate may not be rapid enough for the clinical situation. If the TWR is restricting flow, the caregiver may disengage the TWR, and then reengage it after he or she believes enough fluid flow has carried the medication into the patient. Often, and especially if flow in the system remains restricted after the disengagement of the TWR, a syringe is used at the injection port or three-way stop cock, to withdraw fluid (with negative pressure applied to the syringe) from the intravenous bag or bottle, which is then injected into the patient in order the “bolus” the medication to the patient (this is virtually impossible if the TWR is partially or fully engaged). Another way that flow may be increased is by squeezing the intravenous bag, creating a positive pressure force. If the TWR is not reengaged, the patient will continue to receive increased fluids, which, in some circumstances, may be detrimental.
[0007] In the neonate and infant population fluids are carefully regulated. Failure to reengage a TWR after a drug delivery can be devastating. Additionally, in this patient population, small boluses of fluid (e.g., 5 to 10 cc) may be used therapeutically (e.g., for hypotension). This requires constant disengage-reengagement of the TWR. Again, an error here may be devastating.
SUMMARY
[0008] The present disclosure describes a system for bypassing the TWR to allow rapid fluid (liquid) bolus injection. The system may allow an operator to withdraw (from an intravenous fluid bag) and inject a small amount of fluid through the intravenous line, without adjusting the TWR, to aid in medication delivery, improve patient care and save the caregivers time and energy.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 depicts a generic intravenous administration set.
[0010] FIG. 2 depicts a generic intravenous administration set with add on components.
[0011] FIG. 3 depicts an exemplary embodiment of a bypass valve having a ball bearing and spring mechanism.
[0012] FIG. 4 depicts an intravenous administration set that includes a bypass valve.
[0013] FIG. 5 depicts an exemplary embodiment of a bypass valve as an add on component to a generic intravenous administration set.
[0014] FIG. 6 depicts an exemplary embodiment of a bypass valve as an integral part of an intravenous administration set.
[0015] FIG. 7 depicts an exemplary embodiment of a one-way pressure-operated valve separate from a thumb-wheel regulator.
[0016] FIG. 8 depicts an alternative exemplary embodiment of a bypass valve with a plunger and spring mechanism.
[0017] FIG. 9 depicts an exemplary embodiment of a bypass valve with a clip applied to the proximal annular ring.
[0018] FIG. 10 shows a top view of the proximal annular PVC ring with the ball bearing in place.
[0019] FIG. 11 shows a top view of the proximal annular PVC ring with the ball bearing in place, with the clip distorting the shape of the annular ring.
DETAILED DESCRIPTION
[0020] The present disclosure provides a system for acutely bypassing the flow restriction of the universally used thumb-wheel regulator (TWR) on intravenous fluid administration lines. This bypass may be required when an emergency medication is administered to the patient via an established intravenous infusion line, as well as when non-emergency medications are given, or in other circumstances in which the administration of a bolus is desired.
[0021] The Intravenous Fluid Bypass Valve (IVFBV) is an integral TWR-valved conduit. The IVFBV may function as a TWR in its neutral state. When a significant negative pressure is applied distal to the IVFBV (e.g., by a syringe attached to the intravenous port or three-way stopcock), the conduit valve opens and allows free flow of fluid past the TWR portion. When negative pressure ceases, the valve closes and the TWR once again functions to restrict flow. When positive pressure is applied to the valve (e.g., by the squeezing of the intravenous bag) the valve opens, allowing increased flow. The valve closes when positive pressure is released. Flow may then resume at the rate set by the TWR without having to re-set the TWR.
[0022] In one exemplary embodiment, a bypass valve may include: a) a Y-split in the intravenous tubing, b) an opaque or clear housing split by a septum into two longitudinal chambers, c) a TWR wheel on the lateral surface of one chamber, which progressively restricts flow in the intravenous tubing as its position is changed, d) a one-way, pressure operated valve in the second chamber (detailed below), and e) Y-rejoining of the intravenous tubing as it leaves the chamber.
[0023] The one-way valve may be selected, constructed, and/or arranged so that it will not open below a threshold pressure difference across the valve. The threshold pressure difference may be so selected as to exceed the normal pressure difference across the valve created by the fluid in the tubing and bag above the valve. In this way, the pressure of ordinary flow will not be sufficient to open the valve; instead, additional pressure must be applied to open the valve. The additional pressure may be supplied, for example, by squeezing the W bag proximal to the valve or by suctioning using a syringe distal to the valve.
[0024] The one-way, pressure operated valve may reside completely within a length of intravenous like PVC tubing, within the second chamber of the housing. This tubing is of larger diameter than the remaining tubing of the intravenous system to allow for flow restriction caused by the valve mechanism. The proximal and distal ends of the valve are demarcated by annular rings of PVC (molded as part of the valve tubing). The centers of these annular rings are the lumens of fluid flow into and out of the valve. A ball bearing made of stainless steel, plastic, or other material sits beneath the proximal (intravenous bag/bottle side) ring, obstructing the lumen in the neutral state. Beneath the ball bearing is a spring, holding the ball bearing into the lumen of the proximal annular ring. The distal end of the spring is held in place on the distal annular ring.
[0025] Regardless of the position of the TWR, as negative pressure is applied to the distal system (via a syringe at the distal injection port or stopcock), or as positive pressure is applied to the proximal system (via pressure on the intravenous bag), the valve opens and flow is momentarily increased. Once negative or positive pressure is relieved, the valve closes, and the system is once again regulated by the position of the TWR. The rate of fluid flow is immediately returned to the rate which had been set by the TWR previously.
[0026] The IVFBV may be an integral part of an intravenous administration system, acting as the TWR for the system. The IVFBV may also be used as an “add-on” device between the intravenous administration system and the patient (then used as an add-on the TWR of the intravenous administration system would be disengaged at all times.
[0027] Additional components which may be added include a) a one way flow valve, b) an injection port for medication administration, c) a stop-cock, such as a three-way stop-cock, or d) extension tubing.
[0028] The tubing distal to the IVFBV may include a sideport for receiving a needle or needleless syringe for addition of fluid to the intravenous line.
[0029] In some embodiments, the bypass valve need not be enclosed by a housing.
[0030] In some embodiments, a bypass valve may include a one-way pressure-operated valve as described connected to proximal and distal lengths of tubing. The proximal tubing may connect to one branch of a proximal Y-split, with the stem of the proximal Y-split having a spike for introducing into a fluid bag. The other branch of the proximal Y-split may be configured to receive the tubing of a generic intravenous set that would normally be attached directly to the fluid bag. The distal tubing may incorporate or connect to a distal connector, such as a Y-split, a stopcock, or other connector, that engages a downstream device, such as a catheter, injection port, etc. The connector may be, for example, a luer lock or a needle, among other things. The distal connector may also receive the tubing of a generic intravenous set that would normally be attached to the downstream device. This arrangement may be well-suited for “retrofitting” existing generic intravenous sets with a bypass valve.
[0031] An alternative configuration of the IVFBV employs a plunger-shaped valve stop. The annular PVC rings and spring are similar to that described above. The plunger handle faces downwards within the spring. The plunger head sits on top of the spring and, in the neutral position, seals against the underside of the proximal annulus. Other valves may be used in place of the ball- and plunger-valves described, such as disc valves, check valves, and flapper valves, among others.
[0032] In some embodiments, the IVFBV may include a clip mechanism that pinches and distorts the proximal PVC annular ring from a circular to an oval opening. This clip would allow for the conduit chamber to fill with fluid when the W fluid bag is spiked, in order to rid the entire system of air before connecting the system to the patient. The IVFBV may also include an air vent to facilitate purging the line of air when it is hooked to an IV bag. The vent may be a one-way valve that permits air to leave the system but not to enter it. The IVFBV may also include a bulb pump to facilitate drawing up and administering a bolus.
[0033] Other examples of one-way valves include a duck valve and a one-way flap valve.
[0034] FIG. 1 shows a standard intravenous administration system. Universally, these include a fluid bag 1 spike and drip chamber 2 , intravenous tubing 3 , TWR 4 , and an adaptor 5 for a compatible intravenous catheter.
[0035] FIG. 2 shows the additional components that are commonly added to the standard intravenous administration set, including a three-way stopcock 6 , injection port 7 , extension tubing 8 , and intravenous catheter 9 .
[0036] FIG. 3 shows the IVFBV with the Y-split in the N tubing 11 , the housing 12 , including a septum 13 within the housing, the conduit bypass valve 10 , which includes the two PVC rings 14 , a ball bearing 15 , and spring 16 . The TWR 4 adjusts the flow of fluid in a parallel tubing. An air vent 22 provides a route for air to leave the system as the tubing fills with fluid.
[0037] FIG. 4 depicts an intravenous administration set that includes a bypass valve 10 .
[0038] FIG. 5 shows the IVFBV as it might be used as an add-on component to a standard intravenous administration set.
[0039] FIG. 6 shows the IVFBV manufactured as an integral part of an intravenous administration set, with a syringe 17 attached to the stopcock 6 .
[0040] FIG. 7 depicts a bypass valve in which the one-way pressure-operated valve 30 is separate from the TWR 4 . The pressure-operated valve is attached to proximal tubing 31 which is connected to one branch of proximal Y-split 32 . The stem of the proximal Y-split is inserted in an IV fluid bag. The pressure-operated value is also attached to distal tubing 33 which is connected to distal connector 34 (shown as a stopcock). A traditional N set extends from the other branch of the proximal Y-split to the distal connector.
[0041] FIG. 8 demonstrates an alternative embodiment with annular PVC rings and the spring in a position similar to that described above. The plunger handle 18 faces downwards within the spring. The plunger head 19 sits on top of the spring and, in the neutral position, seals against the underside of the proximal annulus.
[0042] FIG. 9 demonstrates the IVFBV with a clip 20 applied that distorts the shape of the proximal annular PVC ring.
[0043] FIG. 10 shows a top view of the proximal annular ring, which is in the shape of a doughnut 14 and the ball bearing underneath the ring 15 , shown here in a dotted line. The housing 12 contains the septum 13 on the side of the annular ring.
[0044] FIG. 11 shows the annular ring 14 distorted with the clip 20 in place, which allows fluid to enter the valve without pressure applied (either positive or negative). The tab 21 coming off the clip holds the clip in place on the housing 12 , and the clip can be removed by detaching the tab from the housing.
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An intravenous fluid administration apparatus may include a proximal conduit having a spiked first end for attaching to a reservoir of fluid and a second end, a distal conduit, an intermediate conduit network providing fluid communication from the proximal conduit's second end to the distal conduit and including first and second constituent conduits that provide parallel paths from the proximal conduit to the distal conduit, a flow regulator so engaged with the first constituent conduit as to enable control of fluid flow therethrough, and a pressure-responsive valve so interposed in the second constituent conduit as to permit flow from the proximal conduit to the distal conduit through the second constituent conduit when a fluid pressure difference across the valve exceeds a threshold and to prevent such flow when the difference does not exceed the threshold.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. provisional application No. 60/718,298 filed on Sep. 20, 2005 and U.S. provisional application No. 60/742,516 filed on Dec. 6, 2005. The aforementioned applications are herein incorporated by this reference in its entirety.
ACKNOWLEDGEMENT OF GOVERNMENT SUPPORT
[0002] This work was supported by NARSAD grant “Allosteric Potentiators of mGIuR5 as a Novel Approach for Treatment of Schizophrenia,” NIH/NIMH R01 MH062646-“Regulation of Signaling by mGluR5,” and NIH grant F32 NS049865. The government has certain rights in the invention.
FIELD OF THE INVENTION
[0003] The present invention relates to new compounds and their pharmaceutical uses based on their having partial, non-competitive antagonistic activity at the metabotropic glutamate receptors (mGluR5).
BACKGROUND OF THE INVENTION
[0004] Glutamate is the major excitatory neurotransmitter in the central nervous system, exerting its effects through both ionotropic and metabotropic glutamate receptors (mGlu receptors). The mGlu receptors are members of the family C G protein-coupled receptors (GPCRs), distinguished from other families of GPCRs by a large extracellular N-terminal agonist binding site (see Conn P J and Pin J P (1997) Pharmacology and functions of metabotropic glutamate receptors, Annu Rev Pharmacol Toxicol37:205-37 and Pin J P and Acher F (2002). The metabotropic glutamate receptors: structure, activation mechanism and pharmacology, Curr Drug Targets CNS Neurol Disord 1:297-317 for reviews). The mGlu receptors provide a mechanism by which glutamate can modulate or fine tune activity at the same synapses at which it elicits fast synaptic responses. There are eight known members of the mGlu family, divided into three groups based on sequence homology, pharmacology and coupling to intracellular signaling pathways. Group I mGlu receptors (mGlu I and mGluR5) are primarily localized at postsynaptic sites and couple to Gαq and increases in intracellular calcium. Group II (mGlu2 and mGlu3) and group III (mGlu4, mGlu6, mGlu7 and mGlu8) mGlu receptors are predominantly localized presynaptically, and couple to Gαi/o and associated effectors such as inhibition of adenylyl cyclase and various ion channels.
[0005] The group I receptor mGluR5 has been implicated in a number normal physiological processes in the central nervous system (CNS) and previous studies suggest that selective agonists and antagonists of mGluR5 could have utility for treatment of a number of CNS disorders, including pain (Varney M A and Gereau R W (2002) Metabotropic glutamate receptor involvement in models of acute and persistent pain: prospects for the development of novel analgesics. Curr Drug Target CNS Neurol Disord 1 :283-96), anxiety disorders (Swanson C J, Bures M, Johnson M P, Linden A M, Monn J A and Schoepp D D (2005) Metabotropic glutamate receptors as novel targets for anxiety and stress disorders. Nat Rev Drug Discov 4: 131-44. Spooren W and Gasparini F (2004) mGluR5 receptor antagonists: a novel class of anxiolytics? Drug News Perspect 17:251-7), Parkinson's disease (Marino M J and Conn J P (2002) Modulation of the basal ganglia by metabotropic glutamate receptors: potential for novel therapeutics. Curr Drug Target CNS Neurol Disord 1 :23950), addiction (Kenny P J and Markou A (2004) The ups and downs of addiction: role of metabotropic glutamate receptors. Trends Pharmacol Sci 25:265-72) and schizophrenia (Marino M J, Wittmann M, Bradley S R, Hubert G W, Smith Y and Conn P J (2001) Activation of group I metabotropic glutamate receptors produces a direct excitation and disinhibition of GABAergic projection neurons in the substantia nigra pars reticulata. J Neurosci 21:7001-12; Moghaddam B (2004) Targeting metabotropic glutamate receptors for treatment of the cognitive symptoms of schizophrenia. Psychopharmacology (Berl) 174:39-44).
[0006] Unfortunately, it has been difficult to develop compounds that act as selective ligands at the orthosteric glutamate binding site of mGluR5 or other individual mGlu subtypes that have properties that are likely to be suitable for development of therapeutic agents.
[0007] It is an object of the invention to provide novel partial mGIuR5 antagonist compounds that do not suffer from disadvantageous side-effects, but which still offer therapeutic activity.
SUMMARY OF THE INVENTION
[0008] The above and other objects are realized by the present invention, one embodiment of which relates to partial, non-competitive mGluR5 antagonist compounds, excluding 2-(2-(3-methoxyphenyl)ethynyl)-5-methyl pyridine (M-5MPEP) and 2-(2-(5-bromopyridin-3-yl)ethynyl)-5-methylpyridine (Br-5MPEPy), effective for the treatment of conditions and disorders for which full mGluR5 antagonists may be effective, such as, e.g., anxiety, epilepsy, schizophrenia and other psychotic disorders, Parkinson's disease, addictive disorders, and the like.
[0009] In a further embodiment the partial non-competitive mGluR5 antagonist compounds exclude N-(1,3-diphenyl-IH-pyrazol-5yl)benzamides; N-[4-chloro-2-[(1,3-dioxo-1,3-dihydro-2H-isoindol-2-yl)methyl]phenyl]-2hydroxybenzamide (CPPHA); 3,3′-difluorobenzaldazine (DFB); 2-methyl-6-(phenylethynyl)-pyridine (MPEP); and 3-[(2-methyl-1,3-thiazol-4-yl)ethynyl]pyridine (MTEP).
[0010] Specific examples of partial MgluR5 antagonists of the invention include those compounds having the formula:
[0011] wherein:
[0012] Z is, independently N or —CH—, provided that one, and only one Z is N;
[0013] R is halogen (e.g., Br, F and the like), alkyl (e.g., methyl), alkenyl (e.g., CH═CH2, aryl (e.g., phenyl), heterocyclic (e.g., thiophenyl).
[0014] A further embodiment of the invention provides the use of the above partial, non-competitive mGluR5 antagonist compounds of the invention for the treatment of conditions and disorders for which full mGluR5 antagonists are potentially effective, such as, e.g., anxiety, epilepsy, schizophrenia and other psychotic disorders, Parkinson's disease, addictive disorders, and the like.
[0015] A still further embodiment of the invention concerns the use of the partial, non-competitive mGluR5 antagonist compounds of the invention in the manufacture of a pharmaceutical composition for the treatment of any of the above-described conditions and disorders.
[0016] An additional embodiment of the invention provides a method of treating any of the above-described conditions and disorders in a subject in need of such treatment, comprising administration to such subject of a therapeutically effective amount of a partial, non-competitive mGluR5 antagonist compound of the invention.
[0017] In a further embodiment of the methods and uses related to treating the disorders disclosed herein, examples of partial MgluR5 antagonists of the invention include compounds having the formula:
[0018] wherein
[0019] R 1 is a halogen (e.g., F), alkyl group (e.g., methyl), alkenyl group (e.g., CH═Ch 2 , aryl group (e.g., phenyl), heterocyclic group (e.g., thiophenyl), and the like.
[0020] R 2 is an alkyl group and Hal is a halogen.
[0021] Another embodiment of the invention relates to a pharmaceutical composition incorporating as active agent an effective amount of a partial, non-competitive mGluR5 antagonist compound of the invention for use in the treatment of any of the above-described conditions and disorders.
[0022] A further embodiment of the invention concerns an article of manufacture comprising packaging material and a pharmaceutical agent contained within the packaging material, wherein the pharmaceutical agent is effective for the treatment of a subject suffering from any of the above-described conditions and disorders, and wherein the packaging material comprises a label which indicates that the pharmaceutical agent can be used for ameliorating the symptoms associated with the condition or disorder, and wherein the pharmaceutical agent is a partial, non-competitive mGluR5 antagonist compound, excluding 2-(2-(3-methoxyphenyl)ethynyl)-5-methyl pyridine (M-5MPEP) and 2-(2-(5-bromopyridin-3-yl)ethynyl)-5-methylpyridine (Br-5MPEPy), effective therefor.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] FIG. 1 . Chemical structures of allosteric ligands of mGluR5.
[0024] FIG. 2 . MPEP analogs do not fully antagonize the mGluR5 receptor response to glutamate in rat cortical astrocytes. (A) Representative traces show mGluR5 response induced by glutamate in the presence of MPEP and MPEP analogs. Compounds (10 μM) were added to cells loaded with a calcium sensitive dye and incubated for 5 min. A nearly maximal concentration of glutamate was added and the calcium response measured by the FDS S plate reader. (B) Bar graph illustrates the means of three independent experiments plotted as a percentage of the maximum response to glutamate. Error bars represent SEM.
[0025] FIG. 3 . MPEP analogs inhibit the binding of [3H]methoxyPEPy to membranes from cells expressing mGluR5. Membranes prepared from rat mGluR5 HEK293a cells (10 μg/well) were incubated with radiolabeled MPEP analog [3H]methoxyPEPy (2 nM) in the presence of varying concentrations of MPEP analogs for 60 min at room temperature. Samples were filtered through glass fiber filters and washed extensively. Non-specific binding was estimated with 5 μM MPEP. Concentration response curves were generated from the means of three separate experiments. Error bars represent SEM.
[0026] FIG. 4 . 5MPEP does not antagonize the mGluR5 receptor response to glutamate in rat cortical astrocytes. Varying concentrations of MPEP and MPEP analogs were added to calcium sensitive dye loaded cells and incubated for 5 min. A nearly maximal concentration of glutamate was added and the calcium response measured by the FDSS plate reader. Concentration response curves were generated from the mean data of three experiments. Data are plotted as a percentage of the maximum response to glutamate. Error bars represent SEM.
[0027] FIG. 5 . 5MPEP does not alter the concentration response relationship of mGluR5 to glutamate. MPEP analogs (10 μM) were added to calcium sensitive dye loaded cells and incubated for 5 min. A range of glutamate concentrations was added and the calcium response measured by the FDSS plate reader. Concentration response curves were generated from the mean data of at least three experiments. Data are plotted as a percentage of the maximum response to 100 M glutamate. Error bars represent SEM.
[0028] FIG. 6 . 5MPEP reduces allosteric inhibition of mGluR5 by MPEP in a concentration dependent manner. Varying concentrations of (A) 5MPEP, (B) M-5MPEP and (C) Br-5MPEPy were added to calcium sensitive dye loaded cells followed 1 min later by addition of a single concentration of MPEP (50 nM). After a 5 min incubation, a nearly maximal concentration of glutamate was added and the calcium response measured by the FDSS plate reader. For comparison, the concentration response relationship of each compound on the response to glutamate alone is shown. Concentration response curves were generated from the mean data of three experiments. Data are plotted as a percentage of the maximum response to glutamate. Error bars represent SEM.
[0029] FIG. 7 . 5MPEP reduces allosteric inhibition by MPEP in a competitive manner. (A) Multiple concentrations of 5MPEP (3, 10 or 30 μM) were added to calcium sensitive dye loaded cells followed I min later by addition of varying concentrations of MPEP. After a 5 min incubation, a nearly maximal concentration of glutamate was added and the calcium response measured by the FDSS plate reader. Concentration response curves were generated from the mean data of three experiments. Data are plotted as a percentage of the maximum response to glutamate. Error bars represent SEM. (B) Schild analysis of results indicates inhibition of MPEP by 5MPEP is competitive (slope=1.076±0.0094, x-intercept=−6.249).
[0030] FIG. 8 . (A) DFB and CDPPB, two structurally distinct classes of mGluR5 potentiatiors. (B) 5MPEP reduces allosteric potentiation of mGluR5 response by DFB and CDPPB. Either CDPPB (3 μM) or DFB (30 μM) was added to calcium sensitive dye loaded cells and incubated for 5 min. A suboptimal concentration of glutamate was added and the calcium response measured by the FDSS plate reader. For neutral ligand experiments, 5MPEP (30 μM) was added to calcium sensitive dye loaded cells followed 1 min later by addition of a single concentration of CDPPB (3 μM) or DFB (30 μM). After a 5 min incubation, a suboptimal concentration of glutamate was added and the calcium response measured by the FDSS plate reader. The bar graph represents the mean data of three experiments. Data are plotted as a percentage of the maximum response to 100 μM glutamate. (C) 5MPEP reduces allosteric potentiation of mGluR5 response by CDPPB in a concentration dependent manner. Experiments were performed as described in (B). The concentration response curve was generated from the mean data of four experiments. Data are plotted as a percentage of the maximum potentiation of a suboptimal glutamate response. Error bars represent SEM.
[0031] FIG. 9 . 5MPEP inhibits the effects of MPEP on mGluR5 receptor responses in STN neurons. (A) Representative traces show depolarization of STN neurons by application of DHPG (100 μM); effect of MPEP (10 μM) on DHPG-induced depolarization; and DHPG-induced depolarization of STN neurons in the presence of MPEP (10 μM) and 5MPEP (100 μM). (B) Bar graph (Mean±SEM) illustrates depolarization of STN neurons by DHPG (n=8 cells), DHPG plus MPEP (n=12 cells), and DHPG in the presence of 5MPEP plus MPEP (n=9 cells). *p<0.01; Student's t test.
[0032] FIG. 10 . 5MPEP inhibits the effects of CDPPB on mGluR5 receptor responses in STN neurons. (A) Representative traces show depolarization of STN neurons induced by DHPG (10 μM); potentiation effect of CDPPB (10 μM) on DHPG-induced depolarization; and DHPG-induced depolarization of STN neurons in the presence of CDPPB (10 μM) and 5MPEP (100 μM). (B) Bar graph (Mean±SEM) illustrates depolarization of STN neurons by DHPG (n=6 cells), DHPG plus CDPPB (n=8 cells), and DHPG in the presence of 5MPEP plus CDPPB (n=10 cells).*p<0.01; Student's t test.
[0033] FIG. 11 similarly to the figures above, demonstrates a range of partial activities for several of the compounds depicted below; YP260, YP561, YP562, YP563, YP564, YP565, YP566, YP567.
DETAILED DESCRIPTION OF THE INVENTION
[0034] The present invention is predicated on the discovery that compounds that function as partial mGluR5 antagonists, excluding 2-(2-(3-methoxyphenyl)ethynyl)-5-methyl pyridine (M-5MPEP) and 2-(2-(5-bromopyridin-3-yl)ethynyl)-5-methylpyridine (Br-5MPEPy), that bind to the MPEP site on mGluR5 but have only partial inhibition effects on the mGluR5 response are useful for the treatment of the same conditions and disorders for which full mGluR5 antagonists are useful, but do not suffer from the same disadvantages associated with the latter. Exemplary of these compounds are compounds provided below which act as “partial antagonists” of mGluR5 in that they only partially inhibit the response of this receptor to glutamate. These are clearly distinct from partial agonists at orthosteric sites in that they do not activate the receptor.
[0035] It will be appreciated by those skilled in the art that the above-described specific compounds and classes of compounds are merely exemplary of the compounds of the invention and that the invention includes any compound which is a partial mGluR5 antagonist.
[0036] “A partial mGluR5 antagonist” of the invention can be an antagonist that exhibits a statistically significant antagonist activity that is statistically significantly less than the antagonist activity, for example, of MPEP.
[0037] The “partial mGluR5 antagonists” of the invention are useful for the treatment of anxiety and other related nervous system disorders, such as those mentioned above which provide the benefits of mGluR5 antagonists without the adverse side-effects and/or the development of tolerance.
[0038] Anxiety is a fear, apprehension, or dread of impeding danger often accompanied by restlessness, tension, tachycardia, and dyspnea. Other symptoms commonly associated with anxiety include depression, dysthymic disorder, panic disorder, agoraphobia, and other specific phobias, eating disorders, and many personality disorders. In many clinical cases, anxiety is not associated with a clearly defined and treatable primary illness. While in other cases in which a treatable primary disorder is identified, it can be desirable to treat anxiety at the same time as the primary illness. Benzodiazepines are the most commonly prescribed anti-anxiety drugs for the treatment of generalized anxiety disorder and severe anxiety accompanied with panic attacks. However, benzodiazepines produce dose-limiting side effects, including impairment of motor functions and normal cognition, particularly in the elderly, that often result in confusion, delirium and falls with fractures. Sedatives are also commonly used for the treatment of generalized anxiety disorders; while azapirones, such as buspirone, are often prescribed for the treatment of moderate anxiety conditions. Sedatives and azapirones are also associated with dose-limiting impairments in motor function and cognition (Tatarczynska et al., (2001) Br. J. Pharmacol. 132(7):1423-1430; Will et al., (2001) Trends in Pharmacological Sciences 22(7):331-337).
[0039] Thus, there is a need for novel methods for the treatment of generalized anxiety disorder and other nervous system disorders that provide efficacy within a dose range that does not produce corresponding motor and/or cognitive side effects.
[0040] Within the mammalian central nervous system, glutamate is the primary excitatory neurotransmitter and is responsible for the generation of fast excitatory synaptic responses at most CNS synapses. Ionotropic glutamate receptors (iGluRs), including the N-methyl-D-aspartate (NMDA) receptor subtype, are a well characterized family of glutamate receptor cation channels that are responsible for mediating fast synaptic responses at glutamatergic synapses. In addition, glutamate activates metabotropic glutamate receptors (mGluRs), which are coupled to effector systems, through GTP-binding proteins. Group I mGluRs, include mGIuR1 and mGluR5, which couple primarily to increases in phosphoinositide hydrolysis in expression systems whereas group II (mGluRs 2 and 3) and group III (mGluRs 4, 6, 7, and 8) mGluRs couple primarily to inhibition of adenylyl cyclase when expressed in cell lines. Modulation of mGluR subtypes provides a mechanism by which glutamate can modulate or fine tune activity at the same synapses at which it elicits fast synaptic responses. In particular, the modulation of group I receptor mGluR5 has been implicated in a number of pathological CNS conditions including chronic pain, anxiety, Parkinson's disease, addiction and schizophrenia.
[0041] Previous studies have demonstrated that two selective and non-competitive antagonists for mGluR5, 2-methyl-6-(phenylethynyl)pyridine (MPEP) and 3-[(2-methyl-1,3-thiazol-4-yl)ethynyl]pyridine (MTEP) produce anxiolytic-like effects in a number of preclinical assays of stress and anxiety in rodents, which are similar in magnitude to the effects observed using clinically available anxiolytic drugs, including benzodiazepines. However, chronic administration of mGluR5 antagonists produced adverse effects and the development of tolerance to the potentially beneficial effects of these compounds.
[0042] The present invention is predicated on the modulation of mGluR5 through partial antagonism of this receptor. It represents a novel mechanism for producing anxiolytic-like effects and other desirable CNS effects without subsequent dose-limiting side effects including sedation, motor impairment, and the development of tolerance. More particularly, the novel compounds of the invention have been shown to partially antagonize the mGluR5 response to glutamate in rat cortical astrocytes ( FIG. 2 ). In addition, both M-5MPEP and Br-5MPEPy fully inhibited the binding of the MPEP analog [3H]methoxyPEPy to mGluR5 membranes obtained from HEK cells stably expressing the receptor with inhibition constants of 145+60 and 182±50 nM, respectively ( FIG. 3 ).
[0043] To further characterize the partial antagonist properties of M-5MPEP and Br-5MPEPy, both compounds were tested for antagonism of mGluR5-mediated increases in intracellular calcium across a wide range of concentrations. The concentration response curves of M-5MPEP and Br-5MPEPy were both shifted to the right approximately 10-fold when compared to MPEP, while the maximal inhibition of both compounds was approximately 50% that of MPEP ( FIG. 4 ). Moreover, M-5MPEP and Br-5MPEPy blocked the mGluR5 response to glutamate and induced a rightward and partial downward shift of the glutamate concentration response curve, indicating they behave as partial non-competitive antagonists ( FIG. 5 ). In FIG. 6 , the inhibitory activity of MPEP on the glutamate response was only partially blocked by both M-5MPEP and Br-5MPEPy. Taken together the observed partial non-competitive antagonist effects of M-5MPEP and Br-5MPEPy result in subsequent anxiolytic-like effects in preclinical models of stress and anxiety in rodents, similar in magnitude to previously reported anxiolytic-like effects observed using benzodiazepines and MPEP but without the development of tolerance or dose-limiting side effects. In addition, these compounds will have beneficial effects in multiple other disorders of the nervous system where mGluR5 antagonists have been shown to be effective.
[0044] In the following Examples, MPEP and DFB were obtained from commercial sources (Tocris). CDPPB and 5MPEP were synthesized as previously described (Lindsley et al and Alagille et al, supra). M-5MPEP and Br-SMPEPy and their precursor were synthesized as follows:
EXAMPLE 1
5-Methyl-2-trimethylsilanylethynyl-pyridine
[0045] To a solution of 2-bromo-5-methylpyridine (17.4 mmol) in 50 mL of degassed Et3N was added trimethylsilylacetylene (19.1 mmol), CuI, (1.74 mmol) and trans-dichlorobis(triphenylphosphine)palladium (1.74 mmol). The resulting solution was stirred at RT overnight under N2 atmosphere. The black solution was then hydrolyzed with 30 mL of H2O and extracted with Et20 (3×30 mL). Purification of the residue by column chromatography (hexane/Et2O 9/1) provided the desired compound in 81% yield as brown oil. 1H NMR (CDCI3) δ ppm: 0.08 (s, 9H, CH3); 2.30 (s, 3H, CH3); 7.41 (d, 1H, J=7.5 Hz, CHAT), 7.59 (d, 1H, J=7.5 Hz, CHAr); 8.41 (s, 1H, CHAr). 13C NMR (CDCl3) δ ppm: 0.0 (3C, CH3); 18.9 (1C, CH3); 94.0 (1C, C═C); 104.7 (1C, C═C); 126.1 (1C, CHAr); 132 (1C, Cq); 135.2 (1C, CHAr); 141.6 (1C, Cq); 150.7 (1C, CHAr).
EXAMPLE 2
2-(3-Methoxyphenylethynyl)-5-methylpyridine (M-5MPEP)
[0046] To a solution of 5-methyl-2-trimethylsilanylethynylpyridine (5.32 mmol) in 25 mL degassed N,N-dimethylformamide was added successively 3-bromoanisole (6.96 mmol), CuI (0.57 mmol), Et3N (21.2 mmol) and trans-dichlorobis(triphenylphosphine)palladium (29 mmol). The resulting mixture was warmed to 70° C., Bu4NF (5.85 mmol) was added drop-wise, and the reaction was stirred at this temperature 2 h. After cooling, 20 mL of H2O was added and the resulting solution was extracted with EtOAc (4×20 mL). The organic layer was washed with saturated NaCl (3×20 mL), dried over Na2SO4 and evaporated to dryness. Purification of the residue by column chromatography provided M-5MPEP in 52% yield as a yellow oil. HCl salts were prepared by adding 2 M HCl/Et2O to a solution of free base in EtOAc and isolated by suction filtration. 1H NMR (CDC13) δ ppm: 2.20 (s, 3H, CH3); 3.67 (s, 3H, CH3); 6.79 (ddd, 1H, J=8.5, 2.5, 1.0 Hz, CHAr); 7.01-7.02 (m, 1H, CHAr); 7.07 (dt, 1H, J=8.5, 1.0 Hz, CHAr); 7.13 (t, IH, J=8.5 Hz, CHAr); 7.29 (d, 1H, J=7.5 Hz, CHAr); 7.33 (dd, 1H, J=7.5, 2.5 Hz, CHAr); 8.32 (s, 1H, CHAr). 13C NMR (CDCh) δ ppm: 18.8 (1C, CH3); 55.6 (1C, CH3); 88.8 (1C, C═C); 88.9 (1C, C═C); 115.9 (1C, CHAr); 116.9 (1C, CHAr); 123.8 (1C, Cq); 124.6 (1C, CHAr); 127.0 (1C, CHAr); 129.6 (1C, CHAr); 133.1 (1C, Cq); 137.0 (1C, CHAr); 140.8 (1C, Cq); 150.9 (1C, CHAr); 159.6 (1C, Cq). HCl salt mp 171-172° C. Anal. C 15H13NO HC1 0.2H20) C, H, N.
EXAMPLE 3
3-(6-Methylpyridin-2-ylethynyl)-5-bromopyridine (Br-5MPEPy)
[0047] To a solution of 5-methyl-2-trimethylsilanylethynylpyridine (5.32 mmol) in 25 mL degassed N,N-dimethylformamide was added successively 3,5-dibromopyridine (6.96 mmol), CuI (0.57 mmol), Et3N (21.2 mmol) and trans-dichlorobis(triphenylphosphine) palladium (29 mmol). The resulting mixture was warmed to 70° C., Bu4NF (5.85 mmol) was added drop-wise, and the reaction was stirred at this temperature 2 h. After cooling, 20 mL of H2O was added and the resulting solution was extracted with EtOAc (4×20 mL). The organic layer was washed with saturated NaCl (3×20 mL), dried over Na2SO4 and evaporated to dryness. Purification of the residue by column chromatography provided Br-5MPEPy in 41% yield as a clear oil. HCl salt was prepared by adding 2 M HCl/Et2O to a solution of free base in EtOAc and isolated by suction filtration. 1H NMR (CDCh) δ ppm: 2.24 (s, 3H, CH3); 7.32 (d, 1H, J=7.5 Hz, CHAr); 7.38 (dd, 1H, J=7.5, 2.5 Hz, CHAr); 7.86 (t, 1H, J=2.5 Hz, CHAr); 8.34 (s, IH, CHAr); 8.50 (d, 1H, J=2.5 Hz, CHAr); 8.59 (d, IH, J=2.5 Hz, CHAT) 13c NMR (CDCh) δ ppm: 18.9 (1C, CH3); 83.6 (1C, C═C); 93.3 (1C, C═C); 120.3 (1C, Cq); 121.4 (1C, Cq); 127.2 (1C, CHAr); 133.9 (1C, Cq); 137.0 (1C, CHAr); 139.6 (1C, Cq); 141.2 (1C, CHAr); 150.4 (1C, CHAT); 150.7 (1C, CHAr); 151.1 (1C, CHAr). HCl salt mp 166-168° C. Anal. (C13H9N2-HCl-0.6H20) C, H, N.
EXAMPLE 4
Rat Cortical Astrocytes
[0048] Rat cortical astrocytes were prepared as described by Peavy et al. ((2001)
[0049] Metabotropic glutamate receptor 5induced phosphorylation of extracellular signal-regulated kinase in astrocytes depends on transactivation of the epidermal growth factor receptor. J Neurosci 21:9619-28). In brief, neocortices from 2-4 day old Sprague Dawley rat pups were dissected and dissociated in DMEM by trituration with 1 ml pipette tips. The cells were then centrifuged and resuspended in DMEM (containing 1 mM sodium pyruvate, 2 mM L-glutamine, PenStrep) supplemented with 10% FBS in T75 tissue culture flasks; the medium was changed the next day. Cell cultures were maintained at 37° C. in an atmosphere of 95% air/5% CO2 for 6-8 days. Cells were shaken overnight (280-310 rpm) to remove oligodendrocytes and microglia.
EXAMPLE 5
Calcium Fluorescence Assay
[0050] Secondary astrocytes were trypsinzed and replated into poly-D-Lysine coated 384 well plates (Greiner) at 10K cells/well in 20 μL growth medium (DMEM containing 10% FBS, 20 mM HEPES, 2 mM L-glutamine and antibiotic/antimycotic). The second day the medium was changed to growth medium and G-5 supplement (Invitrogen) containing EGF (10 ng/ml), basic fibroblast growth factor (5 ng/ml), insulin (5 μg/ml), and other factors. The cells were nearly confluent within 2 days and resembled the polygonal astrocytic appearance in vivo. The fourth day, approximately 20 hours before experiments, the medium was changed to glutamine free DMEM containing 5% dialyzed FBS, 20 mM HEPES and antibiotic/antimycotic. On day five medium was removed from the plate and the cells incubated with 20 μL of 1 μM Fluo-4AM (Molecular Probes) in assay buffer (Hank's balanced salt solution, 20 mM HEPES and 2.5 mM Probenecid) for 1 h at 37° C. Dye was removed and 20 μL assay buffer was added. Ca2+ flux was measured using the Functional Drug Screening System (FDSS6000 by Hamamatsu).
[0051] Compounds were diluted into assay buffer to a 5× stock which was applied to the cells. For neutral measurements, cells were preincubated with the test compounds for 1 min, potentiator or antagonist was added, and the cells incubated for an additional 5 min. Cells were then stimulated for 2 min with an appropriate concentration of glutamate. For potentiator and antagonist measurements, cells were preincubated with the test compounds for 5 min and then stimulated for 2 min with an appropriate concentration of glutamate. Data were collected at ¼ Hz during the preincubation period and at 1 Hz during the glutamate addition phase of the experiment.
[0052] Raw data were normalized in a three step process: (1) Cell number and non-uniform illumination/imaging were controlled for based on the initial readings for the well, (2) the signal amplitude for the data point immediately preceding the agonist addition was subtracted from each point on the trace, (3) data were normalized to the maximal response for each experiment. Concentration response curves were generated using Prism 4.0 (GraphPad).
EXAMPLE 6
Radioligand Binding Assays
[0053] The allosteric antagonist MPEP analog [3H]methoxyPEPy (Cosford et al., [3H]-methoxymethyl-MTEP and [3H]-methoxy-PEPy: potent and selective radioligands for the metabotropic glutamate subtype 5 (mGluR5) receptor. Bioorg Med Chem Lett 13:351-4, 2003) was used to evaluate the interaction of the test compounds with the allosteric MPEP site on mGluR5. Membranes were prepared from HEK293A cells stably expressing rat mGluR5. Compounds were diluted into assay buffer (50 mM Tris/0.9% NaCl, pH 7.4) to a 5× stock and 20 μL test compound added to each well of a 96 well assay plate. 60 μL aliquots of membranes diluted in assay buffer (10 μg/well) were added to each well. 20 μL [3H]methoxyPEPy (2 nM final concentration in assay buffer) was added and the reaction incubated at room temperature for 60 min with shaking. After the incubation period, the membrane-bound ligand was separated from free ligand by filtration through glass-fiber 96 well filter plates (Unifilter-96, GF/B by Perkin Elmer). The contents of each well was transferred simultaneously to the filter plate and washed 4 times with assay buffer (Brandel Cell Harvester). 30 μL scintillation fluid was added to each well and the membrane-bound radioactivity determined by scintillation counting (TopCount by Perkin-Elmer). Non-specific binding was estimated using 5 μM MPEP.
EXAMPLE 7
Electrophysiology in STN Neurons
[0054] Midbrain slices were prepared from 12 to 15 day old Sprague-Dawley rats as previously described (Awad H, Hubert G W, Smith Y, Levey A I and Conn P J (2000). Activation of metabotropic glutamate receptor 5 has direct excitatory effects and potentiates NMDA receptor currents in neurons of the subthalamic nucleus. J Neurosci 20:7871-9 and Marino M J and Conn P J (2002) Direct and indirect modulation of the N-methyl D-aspartate receptor. CUIT Drug Target CNS Neurol Disord 1: 1-16). After decapitation, brains were rapidly removed and submerged in an ice-cold choline replacement solution containing (in mM): choline chloride 126, KCl 2.5, NaH2PO4 1.2, MgCl2 1.3, MgSO4 8, glucose 10, and NaHCO3 26, equilibrated with 95% 02/5% CO2. The brain was glued to the chuck of a vibrating blade microtome (Leica Microsystems, Nussloch GmbH) and 350 μM thick slices were obtained. Slices were transferred to a holding chamber containing normal artificial cerebrospinal fluid (ACSF) (in mM): 124 NaCl, 2.5 KC1, 1.3 MgSO4, 1.0 NaH2PO4, 2 CaCl2, 20 glucose, and 26 NaHCO3, equilibrated with 95% 02/5% CO2 that was maintained at room temperature. In all experiments 5 μM glutathione, 500 μM pyruvate, and 250 μM kynurenic acid were included in the choline chloride buffer and in the holding chamber ACSF to increase slice viability.
[0055] Slices were transferred to the stage of a brain slice chamber and continually perfused with ACSF (≈3 ml/min). Neurons in the STN were visualized by the 40 × water immersion lens with Hoffman modulation contrast microscope. Patch electrodes were pulled from borosilicate glass on a Narashige vertical patch pipette puller and filled with internal solution (in mM): potassium gluconate 125, NaCl 4, NaH2PO4 6, CaCl2 1, MgSO4 2, BAPTA-tetrapotassium salt 10, HEPES 10, Mg-ATP 2, Na2-GTP 0.3; pH adjusted to 7.3 with 0.5 N KOH. Electrode resistance was 3-7 MS2. All whole cell patch clamp recordings were performed using an Axon MultiClamp 700B amplifier, data were digitized with DigiDatal 322A , filtered (2 kHz) and acquired by the pClamp 9.2 program. After formation of a whole-cell configuration, the recorded neurons were current clamped to −60 m V. Membrane potentials of STN neurons were recorded and the response to mGluR5 receptor activation monitored input resistance was monitored. All compounds were added by addition to the perfusion solution.
[0056] A broad range of compounds based on the MPEP scaffold ( FIG. 1 ) were synthesized. Most of the compounds in this series fully inhibit activation of mGluR5 by glutamate. However, it was unexpectedly found that a subtle change in the position of the pyridyl methyl group of MPEP to form 5MPEP ( FIG. 1 ) results in a compound that is completely inactive in inhibiting mGluR5 receptor responses. See Published US Application 2001/0056084. It was surprising that such a close structural analog of MPEP had no inhibitory effect on the mGluR5 response to glutamate. Thus, two related compounds, M-5MPEP and Br-5MPEPy, were synthesized, derived from the potent mGluR5 antagonists M-MPEP and Br-MPEPy containing similar structural changes, to determine whether this lack of effect was unique to 5MPEP or whether changing the position of this methyl group would also impact activity of related compounds. In addition, the previous studies were performed in CHO cells that had been transfected with mGluR5 and it was desired to verify that 5MPEP is inactive as an mGluR5 receptor antagonist in a native system. To accomplish this 5MPEP, M-5MPEP and Br-5MPEPy were tested for their ability to inhibit mGluR5 receptor-mediated calcium transients in cortical astrocytes. Cortical astrocytes were chosen for these studies because they provide a native system that endogenously expresses high levels of mGluR5 but not of other mGlu receptor subtypes (Peavy R D, Sorensen S D and Conn P J (2002) Differential regulation of metabotropic glutamate receptor 5-mediated phosphoinositide hydrolysis and extracellular signal-regulated kinase responses by protein kinase C in cultured astrocytes. J Neurochem 83: 110-8). Consistent with this, the mGlu receptor agonist glutamate induced a robust calcium mobilization response in these cells and this response was fully blocked by 10 μM MPEP ( FIG. 2 ). Consistent with previous studies in a recombinant system, 5MPEP (10 μM) had no inhibitory effect on the mGluR5 response to glutamate. M-5MPEP and Br-5MPEPy partially inhibited glutamate-induced calcium transients in these cells ( FIG. 2 ).
[0057] The most obvious explanation for the lack of activity of 5MPEP in inhibiting mGluR5 is that this structural change reduces affinity for the MPEP site on this receptor so that 10 μM does not bind to mGluR5. Likewise, a plausible explanation for the relatively small effect of single concentrations of M-5MPEP and Br-5MPEPy is that the affinities of these compounds are drastically reduced so that 10 μM only partially occupies the MPEP site. However, it is unusual for such a subtle structural change to have such a drastic effect on affinity of a ligand for its site. Thus, the affinities of each of these compounds at the allosteric antagonist site for MPEP were detetinined by measuring their ability to displace binding of a close analog of MPEP, [3H]methoxyPEPy, to membranes prepared from HEK293A cells stably expressing rat mGluR5 ( FIG. 3 ). Interestingly, all three analogs fully inhibited the binding of the MPEP analog to mGluR5 membranes at concentrations in the high nM range. The binding affinities of M-5MPEP and Br-5MPEPy (K;=145±60 and 182±50 nM) were slightly higher than that of 5MPEP (K;=388±48 nM), while all three compounds bound to the receptor binding site with a lower affinity than MPEP (K;=4.72±1.50 nM). MPEP (5 μM) was used to estimate non-specific binding (8% of total binding).
[0058] We next determined the effects of a wide range of each of the MPEP analogs on mGluR5 receptor-mediated increases in intracellular calcium ( FIG. 4 ). 5MPEP was inactive as an antagonist of mGluR5 across a range of concentrations that should span the occupancy range for this compound at the MPEP site. Interestingly, M-5MPEP and Br-5MPEPy displayed partial antagonist activity and induced a maximal reduction of the response to glutamate of approximately 50%. The IC50 values of these compounds at inhibiting mGluR5 receptor responses were approximately 300 nM, which is consistent with their affinities at the [3H]methoxyPEPy site. It is an interesting finding from the research on the present invention that 5MPEP does not alter the mGluR5 concentration response relationship to glutamate. MPEP and other full allosteric mGluR5 receptor antagonists induce an insurmountable inhibition of the mGluR5 glutamate concentration response curve and completely inhibit the response to glutamate. Thus, MPEP shifts the glutamate concentration response curve to the right and downward. In contrast, allosteric potentiators of mGluR5 induce a parallel shift of the glutamate concentration response curve to the left. Based on this and the finding that M-5MPEP and Br-5MPEPy are partial antagonists of mGluR5, it was predicted that they would be expected to shift the glutamate concentration response curve to the right and decrease in maximal response. However, they would not be expected to flatten the concentration response relationship of glutamate as is the case for MPEP. Consistent with this prediction, maximally effective concentrations of M-5MPEP and Br-5MPEPy induced a rightward and downward shift of the glutamate concentration response curve, suggesting they behave as partial non-competitive antagonists ( FIG. 5 ).
[0059] The finding that 5MPEP does not block the response to a near maximal concentration of glutamate suggests that this compound should not shift the glutamate concentration response curve to the right. However, it is possible that 5MPEP could act as an allosteric potentiator and shift the curve to the left. Interestingly, 5MPEP had no effect on the glutamate concentration response curve, suggesting that it is neither an allosteric antagonist nor potentiator of mGluR5.
[0060] It was a further interesting finding that 5MPEP blocks MPEP inhibition of mGluR5 induced calcium mobilization. The finding that 5MPEP binds to the MPEP site but does not alter the glutamate concentration response relationship suggests that this compound must be a neutral or silent ligand at this site. If this is the case, 5MPEP would be expected to competitively block the allosteric antagonist response to MPEP. Based on this hypothesis, it was predicted that 5MPEP would bind to the MPEP site of mGluR5 and compete with MPEP, thereby blocking the inhibitory effects of the allosteric antagonist. In a similar manner, if M-5MPEP and Br-5MPEPy are “partial antagonists” at this site, they should also compete with MPEP for binding and block its effects. However, since M-5MPEP and Br-5MPEPy partially inhibit the response to glutamate, they should only partially block the inhibitory response to MPEP. FIG. 6 shows the effects of multiple concentrations of each of these compounds on the calcium mobilization response to glutamate when added alone and in the presence of MPEP. MPEP (50 nM) induces a robust inhibition of the calcium response of mGluR5 to a nearly maximal concentration of glutamate. The concentration response relationship of modulators 5MPEP, M-5MPEP and Br-5MPEPy for blocking the inhibitory activity of MPEP on the glutamate response was determined. For comparison, the concentration response relationship of each compound on the response to glutamate alone is shown. As predicted, each compound induced a concentration-dependent reduction in MPEP induced inhibition of mGluR5. M-5MPEP and Br-5MPEPy only partially blocked the response to MPEP to the level observed with each compound alone. In contrast, 5MPEP fully blocked the response to MPEP in a concentration-dependent manner with an EC50=2.32±0.21 M. As hypothesized, 5MPEP acts as a neutral allosteric ligand by having no impact on the mGluR5 response alone but being capable of blocking the effects of the antagonist MPEP.
[0061] It was also found that 5MPEP blocks MPEP inhibition of mGluR5 activity in a competitive manner. The binding data indicate that 5MPEP competes with [3H]methoxyPEPy for the MPEP binding site and the functional data demonstrate that 5MPEP blocks the inhibitory effects of MPEP on mGluR5 activity. If 5MPEP blocks MPEP action by competitive interaction with a single allosteric site, 5MPEP should induce a parallel shift in the MPEP concentration response curve to the right. FIG. 7 shows the effects of increasing concentrations of 5MPEP (3, 10 and 30 μM) on the MPEP concentration response relationship. As can be seen, each concentration of 5MPEP induced a parallel rightward shift in the MPEP concentration response curve. Furthermore, a Schild analysis of the effects of 5MPEP on the MPEP concentration response yielded a linear regression with a slope of 1.076±0.01 (r2=0.99) indicating the relationship between 5MPEP and MPEP to be competitive. Extrapolation of the line to the x-intercept established a Ki of 560 nM, a result consistent with the Ki value for 5MPEP at the [3H]methoxyPEPy site as determined by radioligand binding. The Schild regression data combined with radioligand binding data led to the conclusion that 5MPEP binds to the MPEP site and blocks MPEP inhibition of mGluR5 induced calcium mobilization in a competitive manner.
[0062] Also surprisingly, it was found that 5MPEP blocks potentiation of mGluR5 induced calcium mobilization by multiple structural classes of potentiators. DFB and CDPPB are allosteric potentiators of mGluR5 derived from two different structural scaffolds, both of which are distinct from the MPEP scaffold ( FIG. 8A ). However, both of these compounds displace [3H]methoxyPEPy binding, leading to the hypothesis that their allosteric potentiator activity is mediated by binding to the same allosteric site as that of MPEP. If this is the case, then the neutral allosteric site ligand 5MPEP should inhibit the allosteric potentiator responses to DFB and CDPPB. Consistent with previous reports in recombinant systems, mGluR5-mediated increases in intracellular calcium in response to a suboptimal concentration of glutamate were potentiated by DFB and CDPPB in rat cortical astrocytes ( FIG. 8B ). Concentrations of DFB (30 μM) and CDPPB (3 tM) used for this experiment were chosen based on a minimum concentration of each required to elicit a maximal potentiator response. 5MPEP (30 μM) does not alter the mGluR5 response to glutamate alone, but completely blocks the allosteric potentiator responses to both DFB and CDPPB ( FIG. 8B ). The concentration response relationship of 5MPEP for blocking the potentiator activity of CDPPB was then determined. CDPPB is the more potent potentiator of the two classes, on the glutamate response relationship ( FIG. 8C ). Inhibition of the potentiator response was found to be concentration-dependent, blocking the response with an IC50=1.71±0.32 M. This is consistent with the concentration response relationship of 5MPEP at blocking the response to MPEP ( FIG. 6 ).
[0063] It was also found that 5MPEP blocks the effects of CDPPB and MPEP on mGluR5 receptor responses in STN neurons. Discovery of 5MPEP as a neutral ligand with sub-μM affinity at the MPEP site on mGluR5 suggests that this compound could provide a valuable tool for evaluating functional responses to allosteric mGluR5 receptor antagonists and potentiators. Thus, any responses to MPEP or CDPPB that are mediated by actions of these compounds on mGluRS should be blocked by 5MPEP. It was previously found that MPEP blocks DHPG-induced depolarization of neurons in the subthalamic nucleus (STN) leading to the suggestion that mGluR5 is important for depolarization of these neurons. Thus, the effect of 5MPEP on STN neurons was determined to discover whether this compound has effects in these cells that are consistent with neutral allosteric site activity. Whole-cell recordings were performed from STN neurons in rat midbrain slices in the presence of TTX (500 nM), which block action potential firing. As reported previously, bath application of DHPG (100 μM) induced a robust depolarization in these cells (14.82+2.21 mV; n=8) ( FIGS. 9A, 9B ). Also, consistent with previous findings, the DHPG-induced response was inhibited by the mGluR5 receptor-selective antagonist MPEP (10 μM) (6.15+0.82 mV; n=12) ( FIGS. 9A, 9B ), suggesting that it is mediated by activation of the mGluR5. Interestingly, 5MPEP had no effect on membrane potential of STN neurons and did not alter the response to glutamate ( FIG. 9A ). However, preincubation with 5MPEP (100 pM) for 10 min completely blocked the inhibitory effect of MPEP on DHPG-induced response (14.28±2.1 mV; n=9) ( FIGS. 9A, 9B ).
[0064] The effect of the allosteric potentiator CDPPB on the response to a lower concentration of DHPG (10 μM) that induces a submaximal depolarization of STN neurons (6.89+1.22 mV; n=6) was next determined ( FIGS. 10A, 10B ). Consistent with the allosteric potentiator effects of CDPPB on mGluR5 in recombinant systems and cortical astrocytes, CDPPB (10 μM) induced a robust potentiation of depolarization of STN neurons by DHPG (10 μM) (13.39±1.66 mV; n=8) ( FIGS. 10A, 10B ). Furthermore, the potentiator response to CDPPB was completely blocked by preincubation with 100 μM 5MPEP (7.05±0.82 mV; n=10). These data provide convincing evidence that CDPPB potentiates electrophysiological responses to mGluR5 receptor activation in STN neurons and indicate that 5MPEP acts as a neutral ligand of mGluR5 in both cortical astrocytes and STN neurons.
[0065] 5MPEP can be characterized as a novel neutral allosteric site ligand of mGluR5. This compound interacts with the allosteric site on mGluR5 in a manner that is directly analogous to that of a neutral antagonist at an orthosteric neurotransmitter binding site. This is also similar to activity that was recently reported for DCB, an analog of DFB that acts as a neutral ligand at this site. However, unlike 5MPEP, DCB did not have sufficient potency and solubility to allow rigorous characterization or use in more complex systems such as brain slice preparations that are reported for 5MPEP. In addition, M-5MPEP and Br-5MPEPy have been identified as two novel compounds that act as “partial antagonists” at the same allosteric site on mGluR5. While these compounds have some similarities to partial agonists at orthosteric sites, they have actions at a functional level that are fundamentally different from those of partial agonists.
[0066] Neutral antagonists at orthosteric sites of GPCRs are similar to 5MPEP in that they bind silently to the orthosteric site and do not activate or decrease constitutive activity of the receptor. However, neutral orthosteric site ligands block the effects of agonists or inverse agonists. Extension of this concept to allosteric sites on GPCRs and the use of this 5MPEP to characterize the pharmacological properties of this allosteric site on mGluR5 provide important insights into the nature of this allosteric site and suggests that ligand interactions with the allosteric site on the mGluR5 receptor follow the same rules of traditional receptor theory that were established with ligand interactions at orthosteric binding sites. Thus, 5MPEP binds to mGluR5 but neither potentiates nor inhibits the response to glutamate when added alone. However, 5MPEP blocks the allosteric antagonist activity of MPEP and the allosteric potentiator activity of CDPPB and DFB. Furthermore, analysis of the effect of 5MPEP on the MPEP concentration response relationship reveals that these ligands regulate functional responses of the receptor in a competitive manner. Thus, analysis of these data using a Schild analysis (Arunlakshana, et al (1959) Some quantitative uses of drug antagonists. Br J Phannacol 14:48-58) suggests a competitive interaction and provides an estimate of the K; value of the neutral ligand that is consistent with that determined by measuring displacement of a radiolabeled ligand to the allosteric site. While analogous to neutral orthosteric ligands, neutral ligands at an allosteric site are fundamentally different in that they are not receptor antagonists. Thus, they do not inhibit the response of mGluR5 to glutamate.
[0067] In addition to providing insights into the pharmacological properties of allosteric sites on GPCRs, discovery of 5MPEP provides a valuable tool and expands the toolbox of ligands available for increasing the understanding of the physiological significance of allosteric modulation of GPCRs. While marked progress in the field of allosteric modulation of mGlu receptors and other GPCRs has recently been made, a true understanding of the mechanism by which these ligands regulate receptor function has yet to be established. Also, there exist few tools that allow one to assess the effects of allosteric agonists and antagonists in native systems. Allosteric potentiators and antagonists such as CDPPB and MPEP are playing a central role in developing an understanding of the functional roles of mGluR5 and other GPCRs. By selectively blocking the effects of a potentiator or antagonist while having no effects on the targeted receptor itself, neutral allosteric ligands such as 5MPEP provide exciting new tools that make it possible to evaluate whether a functional response to an allosteric antagonist or potentiator is actually mediated by the targeted receptor. Continued development of neutral ligands will have a major impact on the forward progress of in vivo studies of allosteric modulators of GPCRs and hence, the understanding of their mechanism or action.
[0068] In addition to blocking effects of exogenously applied or administered allosteric potentiators or antagonists, 5MPEP provides an exciting tool to aid in studies aimed at deteiniining whether endogenous ligands exist for the allosteric site on mGluR5. While tremendous progress has been made in identifying synthetic compounds that act at allosteric sites on GPCRs, the question as to whether endogenous ligands for these sites remains open. Because 5MPEP is inactive in the absence of an allosteric potentiator or antagonist, it will be of interest to determine whether physiological effects of this compound can be observed under some settings. The present research has found that 5MPEP has no effect on mGluR5 in astrocytes or STN neurons when added alone.
[0069] Discovery of the “partial antagonists” of mGluR5 of the present invention also has important implications for the range of activity possible for allosteric site ligands and the potential utility of compounds that interact with the allosteric site. The partial antagonist activity of the compounds of the invention is in some ways analogous to the activity of orthosteric site partial agonists. For both partial antagonists and partial agonists, these compounds will partially block the response of a GPCR to its natural orthosteric ligand. However, unlike partial agonists, M-5MPEP and Br-5MPEPy do not partially activate mGluR5 when added alone. Furthermore, these compounds only partially inhibit the receptor. Such partial antagonists would be useful in settings where there is a need to maintain some level of receptor activity but inhibit effects of excessive receptor activation. This partial antagonist activity is unique to the novel compounds described here and could only be achieved with allosteric site ligands. Thus, this illustrates another important property of ligands at allosteric sites on GPCRs that could not be achieved with orthosteric site ligands and could be useful in discovery of novel therapeutic agents.
[0070] A final important point is that previous studies of the action of allosteric potentiators of mGluR5 have been largely restricted to studies in cell lines in which mGluR5 is overexpressed. The present findings in cortical astrocytes and STN neurons suggest that allosteric potentiators of mGluR5 have effects in these native systems that are virtually identical in nature to those previously described in recombinant systems. Furthermore, inhibition of these responses by 5MPEP, which is structurally dissimilar from either DFB or CDPPB, provides strong evidence that these effects of the allosteric potentiators are mediated by mGluR5. These exciting data provide strong support for the potential utility of allosteric potentiators of mGluR5 for increasing activity of this receptor in a range of cells that natively express this receptor.
[0071] Thus, it will be apparent to those skilled in the art that the partial mGluR5 antagonists of the invention, of which the above-described specific compounds are only exemplary, are useful for the treatment of any condition or disorder for which the full mGluR5 antagonists are useful.
ABBREVIATIONS USED HEREIN
[0072] CNS, central nervous systems; mGlu, metabotropic glutamate receptor; MPEP, 2-methyl-6-(phenylethynyl)-pyridine; methoxy-PEPy, 3-methoxy-5-(2-pyridinylethynyl)pyridine; mGlu, metabotropic glutamate receptor; 5MPEP, 5-methyl-2-phenylethynyl-pyridine; M-5MPEP, 2-(3-methoxyphenyl ethynyl)-5-methylpyridine; Br-5MPEPy, 3-(6-methylpyridin-2-ylethynyl)-5-bromopyridine; CDPPB, 3-cyano-N-(I,3-diphenyl-1 H-pyrazol-5-yl)benzamide; DFB, 3,3′-di fluorobenzaldazine; DCB, 3,3′-dichlorobenzaldazine; DMEM, Dulbecco's modified Eagle's medium; DMSO, dimethyl sulfoxide; FBS, fetal bovine serum; GPCR, G protein-coupled receptor; LBD, ligand binding domain; HEK293A, human embryronic kidney cells; PEI, polyethyleneimine.
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[0076] Marino M J, Conn P I. Related Articles, Links Direct and indirect modulation of the N-methyl D-aspartate receptor. Cun Drug Targets CNS Neurol Disord. 2002 February; 1(1): 1-16. review.
[0077] Marino M J, Conn J P. Related Articles, Links Modulation of the basal ganglia by metabotropic glutamate receptors: potential for novel therapeutics. Curr Drug Targets CNS Neurol Disord. 2002 June;1(3):239-50. Review. Erratum in: Curr Drug Target CNS Neurol Disord. 2002 August; 1 (4):449.
[0078] Varney M A, Gereau R W 4th. Related Articles, Links Metabotropic glutamate receptor involvement in models of acute and persistent pain: prospects for the development of novel analgesics. Curr Drug Targets CNS Neurol Disord. 2002 June;1(3):283-96. Review.
[0079] Moghaddam B. Related Articles, Links Targeting metabotropic glutamate receptors for treatment of the cognitive symptoms of schizophrenia. Psychopharmacology (Berl). 2004 June; 174(1):39-44. Epub 2004 Feb. 19. Review
[0080] Gasparini F, Kuhn R, Pin J P. Related Articles, Links Allosteric modulators of group I metabotropic glutamate receptors: novel subtype-selective ligands and therapeutic perspectives. Curr Opin Pharmacol. 2002 February;2(1):43-9. Review.
[0081] Spooren W P, Gasparini F, Salt T E, Kuhn R. Related Articles, Links Novel allosteric antagonists shed light on mglu(5) receptors and CNS disorders. Trends Pharmacol Sci. 2001 July;22(7):33 1-7 Review.
[0082] Alagille D, Baldwin R M, Roth B L, Wroblewski J T, Grajkowska E, Tamagnan G D. Related Articles, Links Functionalization at position 3 of the phenyl ring of the potent mGluR5 noncompetitive antagonists MPEP. Bioorg Med Chem Lett. 2005 Feb. 15;15(4):945-9. PMID: 15686891
[0083] Alagille D, Baldwin R M, Roth B L, Wroblewski J T, Grajkowska E, Tamagnan G D. Related Articles, Links Synthesis and receptor assay of aromatic-ethynyl-aromatic derivatives with potent mGluR5 antagonist activity. Bioorg Med Chem. 2005 Jan. 3;13(1):197-209.
[0084] Cosford N D, Roppe J, Tehrani L, Schweiger E J, Seiders T J, Chaudary A, Rao S, Varney M A. [3H]-methoxymethyl-MTEP and [3H]-methoxy-PEPy: potent and selective radioligands for the metabotropic glutamate subtype 5 (mGluR5) receptor. Bioorg Med Chem Lett. 2003 Feb. 10;13(3):351-4.
[0085] Marino et al., 2001. M. J. Marino, M. Wittmann, S. R. Bradley, G. W. Hubert, Y. Smith and P. J. Conn, Activation of group I metabotropic glutamate receptors produces a direct excitation and disinhibition of GABAergic projection neurons in the substantia nigra pars reticulata. Journal of Neuroscience 21 (2001), pp. 7001-7012.
[0086] Awad et al., 2000. H. Awad, G. W. Hubert, Y. Smith, A. I. Levey and P. J. Conn, Activation of metabotropic glutamate receptor 5 has direct excitatory effects and potentiates NMDA receptor currents in neurons of the subthalamic nucleus. Journal of Neuroscience 20 (2000), pp. 7871-7879.
[0087] Arunlakshana 0, Schild H O. Some quantitative uses of drug antagonists. 1958. Br J Phalinacol. 1997 February;120(4 Suppl).151-61.
[0088] The entire contents and disclosures of each and every reference, including patents, published patent applications and articles are incorporated herein by reference.
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Provided is a method of treating conditions and disorders for which full mGluR5 antagonists are potentially effective, such as, e.g., anxiety, epilepsy, schizophrenia and other psychotic disorders, Parkinson's disease, addictive disorders, and the like in a subject in need of such treatment, comprising administration to such subject of a therapeutically effective amount of a partial, non-competitive mGluR5 antagonist compound of the invention. Specific examples of partial MgluR5 antagonists provided include those compounds having the formula:
wherein: Z is, independently N or —CH—, provided that one, and only one Z is N; R is halogen (e.g., Br, F and the like), alkyl (e.g., methyl), alkenyl (e.g., CH═CH2, aryl (e.g., phenyl), heterocyclic (e.g., thiophenyl).
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FIELD OF THE INVENTION
The present invention pertains to ball and seat valves. More particularly, the present invention pertains to ball and seat valves designed to yield an increased resistance to failure of the seat when the seat is subjected to high stress.
BACKGROUND OF THE INVENTION
Ball and seat valves for a wide variety of applications have been utilized for a number of years. The seat typically includes a bore adapted to receive and engage the ball, the bore constituting an inlet/outlet for a liquid medium. When the pressure behind the ball is higher than the pressure on the opposite side of the seat, the ball is forced into the bore thereby shutting off the flow of liquid through the valve. When the pressure behind the ball becomes lower than the pressure on the opposite side of the seat, the ball tends to disengage from the seat bore and the liquid can flow freely through the bore. Other factors may affect the circumstances under which the ball engages and seals the bore, such as gravity and buoyancy of the liquid medium.
Many industries have begun to realize a need for ball and seat valves that can withstand both higher pressures and more corrosive environments. For example, subsurface pumps utilized to extract oil from subterranean formations rely on ball and seat valves for efficient extraction of the oil. The operating pressure and environment are very severe, and the failure of a ball and seat valve will cause the pump system to completely cease operation, resulting in costly repair, downtime, and production loss.
Ball and seat valves utilized in the petroleum industry and other industries can be subjected to environments that include very corrosive chemicals such as hydrogen sulfide, carbon dioxide and salt water, for extended periods of time. Often to alleviate some of the problems associated with utilizing ball and seat valves in such environments, ball and seat valves have been manufactured from a variety of materials, typically metallic in nature. For example, stainless steel, nickel-copper alloys, bronze, and other materials such as cemented carbides have been utilized. However, the wear resistance of many of these materials has been found to be insufficient for many applications. The metallic materials tend to wear down and degrade after a period of time, particularly in highly corrosive environments. In the petroleum industry, the valves must often be replaced on a monthly basis.
In some applications, attempts have been made to utilize ceramic materials to alleviate some of these problems. Ceramics are known to be highly resistant to many corrosive environments, such as acids and salt solutions.
U.S. Pat. No. 4,795,133 by Berchem et al., issued Jan. 3, 1989, discloses a ball valve having a valve seat including two sintered ceramic seat rings and a ceramic valve ball. Berchem et al. disclose that the ball valve is especially useful for fluids containing solvents and/or abrasive solids. Similar ceramic ball and seat valves are disclosed by Berchem in U.S. Pat. No. 4,815,704, issued Mar. 28, 1989, and Berchem et al. in U.S. Pat. No. 4,771,803, issued Sep. 20, 1988.
The inherent brittleness of ceramics has severely limited their use in high pressure applications. With ductile metals, localized stresses that exceed the yield point are relieved by local plastic deformation that redistributes the stress into a wider area, preventing fracture.
Ceramics, however, have no such yield point and fail catastrophically when localized stresses exceed the material strength. Ceramics typically have a higher modulus of elasticity than metals which results in fracture at relatively small strains, which compounds the problem. The result is that when the stress on a ceramic seat exceeds the material strength, the seat will fail catastrophically and crack or break apart. The ball and seat valve is then completely useless and must be replaced, resulting in down-time and consequential economic loss.
Attempts have been made to alleviate this particular problem by placing the seat portion of the ball and seat valve in compression. See, for example, "Downhole Products," a sales brochure distributed by Coors Ceramics Company. By placing the seat in compression, tensile force applied by the striking ball would have to overcome the compressive forces to fracture the ceramic. The "Downhole Products" brochure discloses a tightly wrapped stainless steel ring around the seat to place the seat in a compressed state. However, this design is not completely satisfactory since the ceramic seat is still subject to fracturing during assembly and use. Fracture during use can occur primarily because the seating and sealing occurs on two flat, parallel surfaces.
There exists a need in many industries to utilize ball and seat valves in high pressure and highly corrosive environments. A ball and seat valve constructed from a corrosion resistant material, such as a ceramic, would be beneficial. It would be extremely beneficial if the ball and seat valve was designed so that the ceramic is able to withstand a maximum amount of stress without failing catastrophically. It would also be beneficial if this could be achieved without significantly altering the design of present ball and seat valves.
SUMMARY OF THE INVENTION
In accordance with the present invention, an improved design for a ball and seat valve leads to increased reliability and increased resistance to fracture of the seat.
The ball and seat valve includes a spherical ball and a seat wherein the seat includes a beveled surface contiguous with its outer circumference, wherein the beveled surface is adapted to engage and seal against a receiving wall. In one embodiment, the seat is made from a ceramic material. Preferably, the ceramic material is selected from the group consisting of toughened zirconia, alumina, silicon carbide, silicon nitride, and whisker-reinforced composites thereof. The ball may also be made from a ceramic material.
Preferably, the beveled surface on the seat forms an angle with the central axis of the seat of between about 40° and about 50°. More preferably, the angle is about 45°. In one embodiment, the seat includes two beveled surfaces so that the seat may be inserted into a receiving cage in either direction.
In accordance with another aspect of the present invention, a cage assembly includes a ball and seat valve wherein the seat has a beveled surface contiguous with the outer circumference of the seat and a cage is adapted to receive the seat such that the beveled surface contacts and engages the inner surface of the cage, and the seat is forced against the inner surface, such that compressive forces are transmitted inwardly to the bore of the seat by the force exerted on the beveled surface. The assembly is particularly useful in a down hole sucker rod assembly for the extraction of oil from subterranean formations.
The present invention also provides a method for exerting a compressive force on the inner bore of a seat in a ball and seat valve, by providing the seat with a beveled surface on at least one edge, placing the seat in a receiving cage having an inner surface adapted to contact the beveled surface, and applying pressure to the seat to force the beveled surface against the inner surface to create a compressive force component directed toward the inner bore. Preferably, the beveled surface forms an angle with the central axis of the seat of from about 40° to about 50°.
According to another aspect of the invention, a method for extending the useful life of a ball and seat valve by exerting a compressive force toward the inner bore is provided. The compressive force is adjustable by altering the axial force exerted on the seat to change the compressive force exerted by a beveled surface located on the edge of the seat, preferably by adjusting the torque on a threaded plug that pushes against the seat.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows an embodiment of a ball and seat valve in accordance with the present invention.
FIG. 2 shows a cross section of a seat in accordance with the present invention.
FIG. 3 shows an embodiment of a cage assembly including a ball and seat valve in accordance with the present invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
According to the present invention, the outer surface of the seat in a ball and seat valve includes at least one beveled edge. The beveled edge provides improvements in the utility and effectiveness of the ball and seat valve.
One advantage provided by the ball and seat valve of the present invention is an improvement in the strength and resistance to fracture of the seat. When the seat is firmly engaged in a receiving assembly, as discussed hereinbelow, the beveled edge engages the receiving assembly and compressive forces are thereby transmitted inwardly toward the bore of the seat. These compressive forces negate at least a portion of the tensile forces that are created when the ball strikes the bore of the seat.
The ball and seat design of the present invention increases the reliability and strength of a ball and seat valve made from any material. For example, the ball and seat valve may be fabricated from materials such as stainless steel, bronze, hardened alloys, cemented carbides such as titanium carbide or tungsten carbide, oxide ceramics, or non-oxide ceramics. While it is preferred that the ball and seat be constructed from substantially the same type of material, it may be advantageous for some applications to provide a ball and seat that are fabricated from different types of material.
The present invention is particularly useful when the seat is fabricated from a ceramic material. Ceramics are desirable in many ball and seat valve applications due to their inherent high resistance to chemical attack and corrosion. However, ceramics are known to fail catastrophically when subjected to tensile forces. By creating a compressive force component on the bore of the seat the tensile forces created when the ball strikes the seat can be significantly reduced.
A wide variety of ceramic materials may be useful in practicing the present invention. Preferably, the ceramic material has a high strength and a high toughness. For example, toughened zirconia, alumina, silicon carbide, and silicon nitride may be advantageously utilized. Any of the ceramic materials may have an increased toughness through the addition of whiskers or fibers, to create a whisker- or fiber-reinforced composite.
In a more preferred embodiment, the seat is manufactured from transformation-toughened zirconia. Transformation-toughened zirconia includes zirconia that is stabilized with, for example, additions of magnesia, calcia or yttria and also includes zirconia toughened alumina. One type of toughened zirconia available from the Coors Ceramics Company, Golden, Colo., has a flexural strength of about 620 MPa (ASTM test FA17-78), a compressive strength of about 1750 MPa (ASTM test C773-82), a hardness of about 12 GPa, and a fracture toughness of about 11 MPam 1/2 .
Additionally, the beveled edge on the seat of the present invention also forms a sealing surface when the seat is placed into a receiving cage assembly. The beveled edge increases the area of the sealing surface over prior designs, providing an improved seal between the seat and the cage assembly. Thus, the leakage of fluids around the seat is substantially minimized. This is particularly advantageous when the fluid exerts high pressure on the seat.
Additionally, the beveled edge design gives a "self-centering" or aligning affect to the seat. That is, the edge self-aligns the seat in the receiving cage when placed therein.
Referring now to FIG. 1, a ball and seat valve 10 is shown. The ball 14 is substantially spherical and is adapted to engage the seat 18 by sealing against the inner sealing surface 30.
Referring to FIG. 2, the seat 18 includes an inner bore 34 and a outer circumference 46. A beveled edge 22 connects the surface of the outer circumference 46 and a top surface 38. The beveled edge 22 forms an acute angle with the central axis of the seat. Preferably, the angle is between about 40° and about 50°, and more preferably is about 45°.
When the seat 18 is placed into a receiving cage assembly, as discussed hereinbelow, the forces acting on the beveled edge 22 create a compressive force component exerting inwardly toward the bore 34 and, in particular, toward the inner sealing surface 30. Additionally, the surfaces of the beveled edge 22 and the top edge 38 form a large contact area for a sealing surface when engaged in a cage assembly. This increased sealing surface leads to a better seal and a reduction in leakage of fluid around the outside of the seat when compared to seats that have only a single sealing surface. The sealing surface area according to the present invention is the sum of the area of the top surface and the area of the beveled edge.
In the embodiment illustrated in FIGS. 1 and 2, the seat 18 includes a beveled edge on both the top 22 and bottom 26. In this way, the seat can be symmetrical and the direction in which is inserted into its receiving cage is not critical.
Referring to FIG. 3, a cage assembly 50 including a ball and seat valve that is particularly useful for a down hole sucker rod pump assembly is illustrated. Such assemblies are useful for drawing fluids such as oil from subterranean formations.
The downhole cage assembly 50 includes a cylinder 54 for enclosing the ball 14 and seat 18 within the assembly. The cylinder 54 is typically constructed from a metal such as 440 stainless steel or a nickel-copper alloy such as MONEL™ (Huntington Alloy Products Div., International Nickel Co., Inc., Huntington, W. Va.). A plug 58, or other adaptive device such as a connector or plunger, engages the cylinder 54 on the side of the seat 18 opposite the ball 14. Engagement means, such as threads 62, hold the plug 58 into the cylinder 54. The engagement means also maintain the plug 58 forcibly against the seat 18 to push the seat 18 against the inner wall of the cylinder 54. By exerting a force on the seat 18 along the central axis 70, the beveled edges 22 exert an inward force on the seat 18.
The inner wall of the cylinder 54 is adapted to engagedly receive the seat member 18. The cylinder 54 includes a cage element 67 having a first first diameter 66 which is adapted to receive the ball 14. The first diameter 66 is preferably slightly larger than the diameter of the ball 14 so that the ball 14 is not substantially restricted from movement along the central axis 70 of the cage assembly 50.
The cylinder 54 also includes an inner second diameter 74 that is larger than the first diameter 66. The inner diameter 74 is adapted to receive the outer circumference 46 of the seat 18. Thus, when the seat 18 is placed into the second diameter 74, the outer circumference 46 is substantially contiguous with the inner diameter 74 of the cylinder 54.
Between the first diameter 66 of the cage element 67 and inner diameter 74 of the cylinder 54, is a third surface 78 sloped relatively inward toward the central axis 70 of the cylinder 54. This sloped surface 78 is adapted to engagedly receive the beveled edge 22 of the seat 18 and seal the beveled edge 22 against the sloped surface 78.
A force is exerted on the opposite side of the seat 18 by the plug 58 when the plug 58 is affixed into the cylinder 54. The amount of force against the seat 18 can preferably be adjusted by, for example, the torque applied to the plug 58.
Thus, the force exerted on the seat 18 is transferred to the bore of the seat as a compressive force. The state of compression created is useful for improving the fracture resistance of the seat. Additionally, the beveled edge increases the area of the sealing surface for improved resistance to leakage of fluid around the seat. Also, the beveled edge helps the seat properly align in the cage assembly when placed therein.
While various embodiments of the present invention have been described in detail, it is apparent that modifications and adaptations of those embodiments will occur to those skilled in the art. However, it is to be expressly understood that such modifications and adaptations are within the spirit and scope of the present invention.
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The present invention relates to a ball and seat valve having an improved design that increase the reliability and fracture resistance of the seat. The fracture resistance of the seat is increased by providing the seat with a beveled edge. When a force is exerted on the seat along its central axis, the beveled edge creaes a compressive component of force on the inside of the seat. The ball and seat valve is particularly useful when the seat is fabricated from a ceramic material. The ball and seat valve is useful in industries where it is subjected to a highly corrosive environment, such as the oil pumping industry.
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FIELD OF THE INVENTION
The present invention relates to a process for producing semiconductor chips from a semiconductor wafer and, more specifically, to a process for producing a large number of semiconductor chips from a semiconductor wafer having a large number of rectangular areas defined by streets arranged on the surface in a lattice form, semiconductor circuits being formed in the respective rectangular areas.
DESCRIPTION OF THE PRIOR ART
As known to people of ordinary skill in the art, in the production of semiconductor chips, streets are arranged on the surface of a semiconductor wafer in a lattice form to define a large number of rectangular areas, and semiconductor circuits are formed in the respective rectangular areas. Then, the back surface of the semiconductor wafer is ground to reduce the thickness of the semiconductor wafer to a predetermined value. Thereafter, the semiconductor wafer is cut along the streets to separate the rectangular areas from one another to obtain semiconductor chips.
The production of semiconductor chips in the prior art, however, has the following problems to be solved. That is, the grinding of the back surface of the semiconductor wafer is generally carried out by applying a rotary grinding wheel to the back surface of the semiconductor wafer. The rotary grinding wheel comprises a grinding means containing diamond grains, and this grinding means has a substantially flat grinding surface which is pressed against the back surface of the semiconductor wafer. When the back surface of the semiconductor wafer is ground, a cooling liquid such as pure water is jetted over the area to be ground. However, since the grinding surface of the grinding means is substantially flat, the cooling liquid cannot be jetted over the area to be ground sufficiently, and an undesired burn may be formed on the ground back surface of the semiconductor wafer. Further, chippings may not be discharged well from the area to be ground, thereby causing reduction of grinding efficiency.
Further, the cutting of the semiconductor wafer along the streets is generally carried out by applying the rotary cutting blade to the front surface of the semiconductor wafer. At this time, fine chippings may be formed on the back surface of the semiconductor.
SUMMARY OF THE INVENTION
It is therefore the principal object of the present invention to enable to grind the back surface of a semiconductor wafer fully effectively by preventing and suppressing the formation of a burn on the back surface.
It is another object of the present invention to prevent and suppress the formation of chippings on the back surface of the semiconductor chip when a rotary cutting blade is applied to the front surface of the semiconductor wafer to cut the semiconductor wafer along the streets.
According to the present inventor, the above principal object can be attained by a process for producing a large number of semiconductor chips from a semiconductor wafer having a large number of rectangular areas defined by streets arranged on the surface in a lattice form, a semiconductor circuit being formed in each of the rectangular areas, wherein
a plurality of grooves having a predetermined depth are formed in the back surface of the semiconductor wafer, then
the back surface of the semiconductor wafer is ground to be reduced the thickness of the semiconductor wafer to a predetermined value, and thereafter,
the semiconductor wafer is cut along the streets to separate the rectangular areas from one another to obtain semiconductor chips.
In a preferred embodiment of the present invention, the grooves are formed by cutting the semiconductor wafer to a predetermined depth from the back surface with the rotary cutting blade, a grinding means having a substantially flat grinding surface is applied to the back surface of the semiconductor wafer to grind the back surface of the semiconductor wafer, and a rotary cutting blade is applied to the front surface of the semiconductor wafer to cut the semiconductor wafer along the streets. The another object is attained by forming the grooves corresponding to the streets in such a manner that the grooves have a depth larger than the grinding depth of the back surface of the semiconductor wafer and the grooves are still existent even after the back surface of the semiconductor wafer is ground. The width of the grooves is preferably larger than the cutting width at the point when the semiconductor wafer is cut along the streets.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view showing a typical example of a semiconductor wafer to which the present invention is applied;
FIG. 2 is a sectional view for explaining how to form grooves in the back surface of the semiconductor wafer of FIG. 1;
FIG. 3 is a bottom view of the semiconductor wafer having grooves formed in the back surface;
FIG. 4 is a sectional view for explaining how to grind the back surface of the semiconductor wafer having grooves formed in the back surface;
FIG. 5 is a perspective view showing a state that a semiconductor wafer which has grooves in the back surface and whose back surface has been ground is mounted on a frame through a mounting tape; and
FIG. 6 is a sectional view showing how to cut the semiconductor wafer which has grooves formed in the back surface and whose back surface has been ground, along streets.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Preferred embodiments of the present invention will be described in detail hereinafter with reference to the accompanying drawings.
FIG. 1 shows a typical example of a semiconductor wafer to which the present invention is applied. The illustrated semiconductor wafer 2 that has a known per se shape has a substantially disk-like shape as a whole, and its peripheral edge includes a circular arc main portion 4 and a straight portion 6 which is relatively short and called “orientation flat”. Streets 8 are arranged on the front surface of the semiconductor wafer 2 in a lattice form to define a large number of rectangular areas 10 . A semiconductor circuit (its detailed illustration is omitted) is formed in each of the rectangular areas 10 .
Describing with reference to FIG. 2 together with FIG. 1, in the process of the present invention, a plurality of grooves 12 are formed in the back surface of the semiconductor wafer 2 . The formation of the grooves 12 can be carried out advantageously as shown in FIG. 2 . Prior to the formation of the grooves 12 , a protective film 14 which may be an appropriate synthetic resin film is bonded to the front surface of the semiconductor wafer 2 . The semiconductor wafer 2 having the protective film 14 bonded to its front surface is turned upside down (that is, the back surface faces up) and secured on a chuck 16 . A rotary cutting blade 18 which is caused to rotate on a center axis extending substantially in a horizontal direction at a high speed is applied to a predetermined depth D 1 from the back surface of the semiconductor wafer 2 , and the chuck 16 and the rotary cutting blade 18 are moved substantially horizontally in a predetermined direction relative to each other. Preferably, the chuck 16 has a vacuum suction groove or hole in the front surface so as to vacuum adsorb the semiconductor wafer 2 to its front surface. The rotary cutting blade 18 preferably may be a thin disk shaped blade that is formed by incorporating diamond grains into an electrodeposited metal. As shown in FIG. 3, it is desirable that the grooves 12 formed in the back surface of the semiconductor wafer 2 are arranged in a lattice form so as to fully precisely correspond to the streets 8 arranged on the front surface of the semiconductor wafer 2 in a lattice form. In order to form the grooves 12 corresponding to the streets 8 , it is necessary to detect with high accuracy the positions of the streets 8 arranged on the front surface of the semiconductor wafer 2 which is fixed on the chuck 16 and turned upside down. For example, the positions of the streets 8 can be detected with high accuracy by imaging the semiconductor wafer 2 on the chuck 7 with an infrared camera (not shown) and analyzing the image.
The above step of forming the grooves 12 in the back surface of the semiconductor wafer 2 can be advantageously carried out by a dicing saw which is marketed by Disco Corporation which is located in Tokyo, Japan under the trade name of DFD641 or DFD681.
In the process of the present invention, after the grooves 12 are formed in the back surface of the semiconductor wafer 2 , the back surface of the semiconductor wafer 2 is ground to reduce the thickness of the semiconductor wafer 2 to a predetermined value. This grinding can be advantageously carried out as shown in FIG. 4 . The semiconductor wafer 2 having the protective film 14 bonded to the front surface is turned upside down and fixed on the chuck 20 . Preferably, the chuck 20 vacuum adsorbs the semiconductor wafer 2 to its front surface. While the chuck 20 is turned on the center axis extending substantially vertically, the grinding means 24 of a grinding wheel 22 which is rotated on a center axis extending substantially vertically at a high speed are pressed against the back surface of the semiconductor wafer 2 held on the chuck 20 and gradually lowered to grind the back surface of the semiconductor wafer 2 . The grinding wheel 22 includes an annular support member 26 , and a plurality of grinding means 24 extending in an arc form and fixed to the undersurface of the support member 26 . The plurality of grinding means 24 is from a ring as a whole. In place of the plurality of grinding means 24 fixed to the undersurface of the support member 26 , an annular grinding means extending continuously in a circumferential direction may be fixed to the undersurface of the support member 26 . The cross sectional form of each of the grinding means 24 is substantially rectangular and has a substantially flat undersurface, that is, grinding surface. The grinding means 24 are advantageously formed by bonding diamond grains by an appropriate bonding material such as a resin bond. The grinding depth (i.e., thickness removed by grinding) D 2 of the back surface of the semiconductor wafer 2 is somewhat smaller than the depth D 1 of the grooves 12 formed in the back surface of the semiconductor wafer 2 . Therefore, even after the back surface of the semiconductor wafer 2 is ground, the grooves 12 are preferably still existent in the back surface of the semiconductor wafer 2 . For example, when the semiconductor wafer 2 having a thickness of 300 μm is to be ground by a thickness of 100 μm, the depth of the grooves 12 may be about 110 to 120 μm.
Heretofore, the back surface of the semiconductor wafer 2 has been ground without forming the grooves 12 in the back surface of the semiconductor wafer 2 . In this case, a cooling liquid such as pure water to be jetted at the time of grinding could not fully go into the grinding area due to the substantially flat grinding surface of the grinding means 24 , whereby an undesired burn was liable to be formed on the ground back surface of the semiconductor wafer 2 . Further, chippings formed by grinding could not be discharged well from the grinding area, thereby causing reduction of grinding efficiency. In contrast to this, in the process of the present invention, prior to the grinding of the back surface of the semiconductor wafer 2 , a plurality of grooves 12 are formed in the back surface of the semiconductor wafer 2 . The existence of the grooves 12 prevents or suppresses the formation of the undesired burn and promotes the discharge of chippings.
The above-mentioned step of grinding the back surface of the semiconductor wafer 2 can be advantageously carried out by a surface grinder which is marketed by Disco Corporation under the trade name of DFG841.
After the grinding of the back surface of the semiconductor wafer 2 , the semiconductor wafer 2 is cut along the streets 8 arranged on the front surface to separate the rectangular areas from one another to produce semiconductor chips. Preferably, it is advantageous that prior to the cutting of the semiconductor wafer 2 , as shown in FIG. 5, the protective film 14 is peeled off from the front surface of the semiconductor wafer 2 and the semiconductor wafer 2 is required. The frame 30 which can be formed from a synthetic resin or a metal plate has a relatively large circular opening 32 in the center. The semiconductor wafer 2 is positioned in the opening 32 of the frame 30 and the tape 28 extending across the opening 32 of the frame 30 is affixed to the back surface of the frame 30 and the back surface of the semiconductor wafer 2 to mount the semiconductor wafer 2 on the frame 30 . The cutting of the semiconductor wafer 2 can be advantageously carried out as shown in FIG. 6 . The semiconductor wafer 2 mounted on the frame 30 through the tape 28 is held on the chuck 34 . The rotary cutting blade 36 which is rotated on the center axis extending substantially horizontally at a high speed is applied to a depth somewhat larger than the thickness T of from the front surface of the semiconductor wafer 2 to the. bottom surface of the groove 12 formed in the back surface, and the chuck 34 and the rotary cutting blade 36 are moved along the streets 8 relative to each other. The cutting width W 2 of the rotary cutting blade 36 is preferably somewhat smaller than the width W 1 of the groove 12 . For instance, when the cutting width W 2 is 15 μm, the width W 1 of the groove 12 is preferably about 30 μm. Preferably, the chuck 34 vacuum adsorbs the semiconductor wafer 2 to its front surface. The rotary cutting blade 36 preferably may be a thin disk-shaped blade that is formed by incorporating diamond grains into an electrodeposited metal. In the illustrated embodiment, even when the semiconductor wafer 2 is cut along the streets 8 to separate the rectangular areas 10 from one another, the tape 28 is not cut and hence, each rectangular area, that is, the semiconductor chip is affixed to the tape and kept mounted on the frame 30 .
When the semiconductor wafer 2 is cut along the streets 8 as described above after the grooves 12 corresponding to the streets 8 arranged on the front surface of the semiconductor wafer 2 are formed in the back surface of the semiconductor wafer 2 , as shown in FIG. 6, it has been ascertained that the formation of chippings formed on the back surface of the semiconductor wafer 2 can be prevented and suppressed effectively. When the semiconductor wafer 2 is to be cut along the streets 8 , the rotary cutting blade 36 does not need to be contacted to or brought close to the top surface of the tape 28 , whereby the adhesion of an adhesive applied to the front surface of the tape 28 to the rotary cutting blade 36 can be prevented without fail. When the adhesive is stuck to the rotary cutting blade 36 , the rotary cutting blade 36 may be deteriorated in a short period of time.
The above step of cutting the semiconductor wafer 2 along the streets 8 can be advantageously carried out by a dicing saw which is marketed by Disco corporation under the trade name of DFD641 or DFD681, like the aforesaid step of forming the grooves.
While preferred embodiments of the invention have been descried in detail with reference to the accompanying drawings, it should be understood that the invention is not limited thereto and can be changed or modified without departing from the spirit and scope of the invention.
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A process for producing a large number of semiconductor chips from a semiconductor wafer having a large number of rectangular areas defined by streets arranged on the front surface in a lattice form, semiconductor circuits being formed in the respective rectangular areas. This process comprises the steps of forming a plurality of grooves having a predetermined depth in the back surface of the semiconductor wafer, grinding the back surface of the semiconductor wafer to reduce the thickness of the semiconductor wafer to a predetermined value and thereafter, cutting the semiconductor wafer along the streets to separate the rectangular areas from one another to obtain semiconductor chips.
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This application is a continuation of co-pending application Ser. No. 10/467,414 filed on Aug. 8, 2003, which is the 35 U.S.C. §371 national stage of International PCT/IB02/00786 filed on Mar. 13, 2002, which claims priority to Swiss Application No. 0473/01 filed on Mar. 15, 2001. The entire contents of each of the above-identified applications are hereby incorporated by reference. Any disclaimer that may have occurred during prosecution of the above referenced applications is hereby expressly disclaimed.
BACKGROUND OF THE INVENTION
The present invention relates to automatic mechanical car parks. Such car parks generally consist of a containment building, with a reinforced-concrete or steel structure, installed in which are the necessary handling systems and machinery, with automatic collection from the entrance bay, where the user leaves the motor vehicle, and automatic return to the user at the exit bay, of motor vehicle which are contained within the said building throughout the parking period. To be specific, the present invention relates to one of the systems normally used in handling motor vehicles in this field, namely a carriage for the horizontal transfer of the motor vehicles from the parking bay (or from the entrance bay) to a handling platform, the function of which is to transport the carriage, with or without a motor vehicle, between the parking bay and the entrance and exit bays, or from a handling platform to the parking bay (or to the exit bay). During transfer of the vehicle, the handling platform, on which the carriage is normally parked, and the parking bay (or the entrance or exit bay) involved in the transfer, lie in the same plane and their respective longitudinal axes, in the line of the transfer movement, are aligned.
As regards known carriages and accessory systems, the following may be cited as the more significant of the prior art: EP 430892, EP 236278, EP 875644, EP 933493, WO 96/05390, WO 88/04350, DE 3820891, DE 19741638, U.S. Pat. No. 5,148,752, U.S. Pat. No. 3,159,293, U.S. Pat. No. 2,890,802.
None of these satisfactorily solves all of the problems connected with reliable transfer of the motor vehicle, speed of transfer, minimization of the space necessary for transferring and parking the motor vehicle, and minimization of the combined cost of the carriage and associated systems for transferring and parking the motor vehicle.
SUMMARY OF THE INVENTION
The object of the present invention is therefore to solve all of these problems in such a way as to provide a carriage that is innovative in the sum of the distinguishing characteristics which make it optimal for carrying out its functions and for overcoming the limits of the prior art.
These distinguishing characteristics are as follows:
Reliability of transfer of the motor vehicle: Critical is the method of locking on to the motor vehicle which, according to the present invention, is lifted only via its wheels from beneath, so as to reproduce as far as possible its normal operating condition. The wheels of the motor vehicle are locked by the carriage during the transfer in such a way that it does not matter whether or not the handbrake and any gear are or are not engaged, no problems of any kind arising from this during transfer of the motor vehicle. The mass to be transferred is automatically limited by the carriage in order to avoid damage or malfunction caused by vehicles that may be too heavy. When the carriage is transferring the motor vehicle from the entrance bay, as it positions itself underneath the motor vehicle there is a risk that, if the motor vehicle has been left by the user with its longitudinal axis very far from the longitudinal axis of the carriage and if the vehicle has not first been centered by means independent of the carriage, it may interfere, in its movement, with a wheel of the vehicle and get stuck against the tyre; for which reason the width of the carriage of the present invention or at any rate the width of that part of the carriage which rises above the height of the bottoms of the wheels of the vehicle, is made very small so as to allow a generous tolerance of displacement of the longitudinal axis of the motor vehicle from that of the carriage. Systems are also provided to help the user to position the motor vehicle in the entrance bay so that its longitudinal axis is as closely as possible aligned with the longitudinal axis of the carriage. Speed of transfer of the motor vehicle: Given the same acceleration and speed of translational movement of the carriage—which however, within certain limits, can be greater the more securely the vehicle is clamped to the carriage, —the overall speed of transfer is greater if the method of lifting the motor vehicle is such as to minimize this time, and therefore, according to the present invention, this lifting action is carried out simultaneously on all four wheels of the vehicle, following positioning of the carriage underneath the vehicle in one step, rather than first on the two wheels of one axle and then on the two wheels of the other. The shorter the vertical lifting stroke permitted by the design of the carriage, the less time is needed to carry out this function, and therefore, in the carriage of the present invention, the vertical stroke is minimized. The time required to centre the motor vehicle in the carriage of the present invention is superimposed on the time used for another function of the cycle of the carriage. This reduces the total cycle time and increases the speed of transfer of the motor vehicle. Minimization of the amount of space required for transferring and parking the motor vehicle: For the same maximum dimensions of motor vehicles to be stored, the carriage of the present invention allows the parking bays to be very small. On this subject: The width is minimized by the longitudinal alignment of the motor vehicle in the line of the transfer movement (centering). To minimize the length, the carriage is designed to allow the vehicle to be released in the parking bay in a variable position depending on the length of the vehicle itself. To minimize the height, the carriage is the lowest it can be for the vehicle to be able to park, when the carriage is inserted beneath it, with its four wheels resting on a surface only slightly higher than the surface supporting the carriage or supporting the systems that will be carrying it; also, the design of the carriage is such as to allow a very small vertical travel when lifting the four wheels of the motor vehicle off the surface on which they are standing. Minimization of the combined cost of the carriage and associated systems for transferring and parking the motor vehicle: There are functions, such as for example that of centering or that of limiting the load, which at present are performed by dedicated systems, separate from the carriage, but obviously with the increased costs of providing housings and additional supports. It is therefore advantageous that the carriage according to the present invention is able as far as possible autonomously to perform not only its own functions, i.e. transferring the vehicle, but the accessory functions as well. In addition, the biggest cost is represented by the systems that park the vehicles in the parking bays, which, although being “other” than the carriage, must be regarded as a consequence of the design of the carriage itself; and the latter is therefore designed, in the present invention, in such a way as also to minimize the cost of these systems.
The present invention possesses all the optimal characteristics indicated above and is advantageous when compared with all the known inventions cited.
In particular, compared with EP 430892, it has the advantage of greater reliability in the transfer of the motor vehicle because it limits the mass of this motor vehicle and includes the systems for helping the user to position the motor vehicle more accurately in the entrance bay; the advantage, too, of a faster transfer because, without modifying any of the other conditions influencing the length of time required for the transfer cycle to be carried out, it allows a shorter vertical lifting stroke; then, too, the advantage of making it possible for the motor vehicle parking bays to be shorter because it includes systems for sensing the size of the conveyed motor vehicle and for sensing the translational position of the carriage in order that the vehicle can be released in a variable position depending on the length of the vehicle, as well as for the height of the motor vehicle parking bays to be lower due to the design of the carriage which allows lowering of the height, relative to the floor of the parking bay, to which the wheels of the motor vehicle are lifted during the transfer; and lastly, the advantage of a lower combined cost of the carriage and associated systems for transferring and parking the motor vehicle, in that the systems for parking vehicles in the parking bays, which in EP 430892 are highly complicated and expensive, being unable simply to be stood on the floor of the parking bay but having to work cantilever-fashion, can be much simpler and less expensive because they simply stand on the floor of the parking bay.
These and other advantages will be evident from the description of the preferred form of construction and from the characteristics listed in the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
The preferred, but not limiting, form of construction of the invention is described below with reference to the accompanying drawings, in which:
FIG. 1 is a plan view of the transfer carriage according to the invention, positioned on a handling platform 52 with the means 58 and 59 for supporting the wheels of the motor vehicle in the retracted position inside the carriage itself.
FIG. 2 is a plan view of an entrance bay.
FIG. 3 is a plan view of the carriage positioned in the entrance bay with the means for supporting the wheels of the motor vehicle in the extended position.
FIG. 4 is a plan view of an enlargement of one part of the carriage.
FIG. 5 is a cross section through the carriage positioned in the entrance bay with the means for supporting the wheels of the motor vehicle in the retracted position inside the carriage itself.
FIG. 6 is a cross section through the carriage positioned in the entrance bay with the means for supporting the wheels of the motor vehicle in a partially extended position and not raised.
FIG. 7 is a cross section through the carriage positioned in the entrance bay with the means for supporting the wheels of the motor vehicle in the extended position, that is after the vehicle has been centered, and not raised.
FIG. 8 is a cross section through the carriage positioned in the entrance bay with the means for supporting the wheels of the motor vehicle in the extended and raised position.
FIG. 9 is a side view, partially in longitudinal section, of one part of the carriage.
FIG. 10 is a cross section through a system, fitted to the carriage, for limiting the mass that is to be transferred, according to the invention.
FIG. 11 is a plan view of the transfer carriage according to the invention, positioned in a parking bay, in the course of depositing or collecting the motor vehicle.
DESCRIPTION OF PREFERRED EMBODIMENTS
Referring to the drawings, the carriage consists of an articulated frame 1 with hinges and hinge pins 2 to permit relative rotation between the front and rear parts into which the said frame 1 is divided. The front part has four wheels 3 , two of which are driving wheels driven by a motor/speed reducer assembly 4 via a shaft 5 and a chain and toothed wheel system 6 , while the rear part has two driving wheels 3 driven as described above.
The said frame 1 is guided by four rollers 7 acting on the two sides of the trench 53 which is sunk into the entrance and exit bays, the handling platform, and the parking bays.
Electrical power and the signals are supplied to the carriage via a suitable electrical cable 48 which is wound onto a cable reel 50 installed on the handling platform 52 , and is attached to the carriage by a shaped support 51 and guided by pulleys 49 .
The instantaneous position of the carriage, in the direction of longitudinal translation, is known by means of a rotating electronic system 47 mounted on the handling platform 52 to decode the linear displacement of a rope 45 attached to the frame 1 and guided by the pulleys 46 .
This system may conveniently be replaced with other electronic systems suitable for the purpose, e.g. one or more laser signal emitters installed on the carriage and aimed at a fixed reflective surface so as to measure the instantaneous distance between the emitting surface and the reflecting surface.
On each of the front and rear parts of the frame 1 is a frame 8 that can be moved vertically with respect to the frame 1 . Acting via the toothed wheel 13 , the deflecting toothed wheels 13 ′ and the chain 14 , the motor/speed reducer assembly 12 simultaneously turns the toothed wheels 15 and hence the axial cams 16 , of which there are three and which are positioned on the longitudinal axis of the carriage and are capable of lifting both frames 8 , which are borne by the cams, via pairs of arms 9 and steel wheels on roller bearings 17 .
The said cams 16 each have two identical straight helical surfaces rotated through 180°, on which, as the cams rotate, the three pairs of wheels 17 connected to the arms 9 roll and are raised or lowered. The arms 9 , being positioned symmetrically at a certain distance from the longitudinal axis of the carriage, provide stability to the frames 8 .
In order partly to further stabilize the frames 8 against potential loads that may be eccentric with respect to the longitudinal axis of the carriage, and partly to connect the frames 8 one-to-one with the frame 1 , two pins 11 are fixed to the frame 1 , and two bronze bushes 11 ′ integral with the front frame 8 run vertically on these.
A pair of opposing frames 58 are positioned on the two frames 8 to support the wheels 22 and 22 ′ of the front axle of the motor vehicle, and similarly a pair of opposing frames 59 to support the wheels 23 and 23 ′ of the rear axle of the motor vehicle.
Each frame of these pairs of frames 58 and 59 is made up of a centering bar 18 or 18 ′ designed to act horizontally against the inner side wall of the wheels 22 , 23 or 22 ′, 23 ′.
Each bar 18 , 18 ′ has metal supports 19 , 19 ′ situated beneath and perpendicular to the said bar so as to raise the wheels 22 , 23 and 22 ′, 23 ′, respectively, by engaging them from beneath.
Each frame of these pairs 58 and 59 is moved horizontally, symmetrically with respect to the longitudinal axis of the carriage with the opposite frame, by means of the racks 20 , 20 ′, the toothed wheels 30 , the motor/speed reducer assembly 31 and the chain 32 .
The said frames are also equipped with balancing bars 24 and 24 ′ which engage with the guide 10 of the frame 8 via the rollers 25 , 26 and 25 ′, 26 ′ to give stability and guided movement to the frames.
Referring to FIG. 2 , when the dividing door 35 between the entrance bay and the multistorey car park is closed, the user drives the vehicle onto the entrance bay.
The photocells 33 , together with the reflective mirrors 34 , are positioned symmetrically and at a predefined distance relative to the longitudinal axis of the carriage in such a way that, when one of the wheels 22 , 22 ′, 23 and 23 ′ of the motor vehicle comes too close to the said axis, the signal of one of the photocells is interrupted.
While a motor vehicle is moving in, whenever a photocell 35 is cut off the system control activates a light signal indicating to the user that he must modify the direction in which the motor vehicle is moving.
When the wheels, 22 , 22 ′ are positioned on the rest 55 , the sensor 54 enables the stop signal.
As the vehicle is entering, the direction signalling made possible by the photocells 33 helps the user, while after the vehicle has come to a stop, the blocking of the rays of the photocells by one or more wheels is used as a safety lock for the carriage which, if it tried to position itself underneath the motor vehicle to transfer it, would hit one of the wheels of the vehicle.
Referring to FIGS. 3 to 8 , after the motor vehicle has been correctly positioned in the entrance bay and the user has left the vehicle and initiated the parking operation, the doors 35 are opened and the carriage starts the cycle of transferring the motor vehicle by travelling from the handling platform to the entrance bay in the guide trench 53 .
The position at which the carriage stops in the entrance bay is determined in such a way that the axis of the pair of supporting means 58 of the front wheels 22 and 22 ′ of the motor vehicle coincides with the axis of the rests 54 on which the said wheels 22 and 22 ′ have been positioned by the user.
Because the rear wheels 23 and 23 ′ of the motor vehicle may be nearer to or further from the front wheels 22 and 22 ′ depending on the wheelbase of the motor vehicle, the pair of supporting means 59 of the rear wheels 23 and 23 ′ is made elongate in the direction of the longitudinal axis of the vehicle so that it can support the wheels 23 and 23 ′ of the rear axle within the range of variations of the wheelbases of motor vehicles on the market.
Despite the use of signals to minimize the misalignment of the motor vehicle with respect to the longitudinal axis of the carriage as the user is driving in, the front left wheel 22 , referring to the direction of movement of the vehicle, will undoubtedly be at a different distance from the longitudinal axis of the carriage than the front right wheel 22 ′ and the same will go for the rear left wheel 23 as compared with the rear right wheel 23 ′.
The two pairs of wheel supporting means 58 and 59 begin the horizontal outward symmetrical movement.
The metal supports 19 and 19 ′ fit underneath the wheels 22 , 22 ′, 23 and 23 ′ into the free spaces between the fixed supports 28 of the wheels.
Continuing the horizontal outward movement, one of the centering bars 18 or 18 ′—bar 18 in FIG. 6 —meets the side wall of the tyre of the corresponding wheel and pushes it out.
This operation is facilitated by the presence of the rollers 29 inserted in the fixed supports 28 , which minimize the resistance to displacement of the wheel.
Continuing the horizontal outward movement, as shown in FIG. 7 , the centering bar 18 ′ which has hitherto not made contact, now meets the side wall of the tyre of the wheel 22 ′, 23 ′ of the motor vehicle.
At this point the longitudinal axis of the motor vehicle coincides with that of the carriage: the car has been “centered” by the same movement as enabled the wheel supporting means 58 and 59 to position the metal supports 19 and 19 ′ beneath the four wheels 22 , 22 ′, 23 and 23 ′ of the motor vehicle.
The horizontal outward movement of the motor vehicle wheel supporting means 58 and 59 stops when the vehicle is central, that is aligned with the longitudinal axis of the carriage, and this condition occurs when the pressure-sensitive tapes of variable-resistance conductive rubber 21 and 21 ′ applied to the surface of each centering bar 18 and 18 ′ that comes into contact with the motor vehicle tyre are simultaneously compressed, making them electrically conductive, thus enabling the said movement to be stopped.
The amount of horizontal outward movement of the motor vehicle wheel supporting means 58 and 59 is variable as a function of the inside tracks of the two wheels of each axle of the motor vehicle and, when this movement stops, the distance between the pressure-sensitive tapes 21 and 21 ′ applied to the centering bars 18 and 18 ′ is equal to the inside track of the wheels of the corresponding axle of the vehicle.
At this point the motor vehicle wheel supporting means 58 and 59 , extended as described above and pressed against the tyres so as to clamp the wheels 22 , 22 ′, 23 and 23 ′ and prevent them moving on their resting surface, are lifted by the rising of the frames 8 .
To avoid transferring a vehicle whose mass is too great, unacceptable for example on the handling platform, the system shown in FIG. 10 is used to limit the amount of mass that can be lifted by limiting the force transmissible through the chain 14 .
On the output shaft 39 of the lifting speed reducer 12 , the toothed wheel 13 , which passes the torque of the speed reducer 12 to the chain 24 , is housed, by the friction rings 40 , between a hub and an axially movable anchor 41 pressed via the spring 42 by a disc 43 which compresses the spring 42 by a controlled amount adjusted by means of the screw 44 .
Depending on the force exerted by the spring 42 and the coefficient of friction of the friction rings 40 , the toothed wheel 13 can transmit a variable force to the chain 14 to limit how much mass can be raised.
Once the vehicle is raised, the carriage can transfer it to the handling platform.
The job of the sensor 38 is to detect the presence or absence of the motor vehicle on the carriage.
Since the position of the wheels 22 and 22 ′ of the front axle of the motor vehicle is stationary on the carriage, the sensors 36 positioned on the carriage on the longitudinal axis at predefined distances from the axle of the front wheels make it possible to determine whether the distance between the front axle and the front end of the motor vehicle is greater or less than certain preset values.
In the same way, the sensors 37 make it possible to determine whether the distance between the front axle and the back end of the motor vehicle is greater or less than certain preset values.
On the basis of the state of the sensors 36 and 37 and the data from the rotating electronic system 47 , the system control can deposit the motor vehicle, as shown in FIG. 11 , in a variety of positions, and in particular, if the distance between the front axle of the car and the front end is short, it can deposit the motor vehicle in such a way that its front axle coincides with the axis 56 , whereas if this distance is large, it can deposit the motor vehicle in such a way that its front axle coincides with the axis 57 .
The vehicle is deposited by lowering the wheel supporting means 58 and 59 , by lowering the frame 8 , in such a way that the metal supports 19 and 19 ′ fit into the spaces between the fixed supports 28 of the frames 60 installed in the parking bays, allowing the wheels 22 , 22 ′, 23 and 23 ′ to rest on the said fixed supports 28 , after which the supporting means 58 and 59 can be withdrawn horizontally into the carriage in the rest position.
On the basis of the state of the sensor 38 , the data of the rotating electronic system 47 and the lifting or lowering function of the motor vehicle wheel supporting means 58 and 59 , the system control writes to memory whether the parking bay is empty or full.
In other words when the motor vehicle is present on the carriage and the carriage is inside a parking bay, in the right position for releasing or gripping the motor vehicle, the operation of lifting the frames 8 is always interpreted by the control as a collecting operation and hence the parking bay is stored in memory as empty, while the operation of lowering the frames 8 is always interpreted by the control as a depositing operation and hence the parking bay is stored in memory as full.
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Self-propelled carriage on wheels includes:
one or two pairs of supporting elements for the wheels of either or both of the axles of the motor vehicle, these elements being movable symmetrically and perpendicularly with respect to the longitudinal axis of the carriage and designed to center, immobilize and lift from beneath the wheels; elements for limiting the mass to be transferred; elements for sensing, continuously during the transfer, the translational position of the carriage; elements for sensing the presence of the motor vehicle on the carriage and measuring the front and rear lengths of the motor vehicle relative to its front axle; and
elements for sensing excessive displacement of the longitudinal axis of the motor vehicle relative to the longitudinal axis of the carriage when the motor vehicle is being positioned by the user in the entrance bay.
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BACKGROUND OF THE INVENTION
The present invention relates to a data processing method and system for an input/output processing unit which executes retrieval processing, compare operations and set operations of a database management system (DBMS) at a high speed.
Conventionally, control unit and input/output unit such as a disk storage device are respectively assigned a unit address which is a unique identifier thereof. When a unit address is broadcasted together with an access request from a central processing unit, input/output unit, whose unit address is equal to the address, fetches the access request and performs processing. These unit addresses are assigned with hardware configuration definition for input/output units at system generation in a computer system.
For effectively utilizing information, the user requires that a database system provides better functions for (1) easy-learning, (2) use-friendly interface, or (3) high-performance.
A relational database (RDB) meets the above requirements (1) and (2) because of its simple table-type logical data structure.
Conventionally, database machines are often placed behind a host computer or a central processing unit so as to distribute loads of the central processing unit. However, such a structure causes heavy communication overhead between the database machine and the host computer. Also, the database machine has to provide a lot of complicated functions for database processing. A technique related to a CPU built-in type database processor for enhancing the processing speed of a relational database is proposed, for example, in "Nikkei Electronics", No. 414, pp. 185-206 (Feb. 9, 1987).
On the other hand, there has been proposed another configuration in which a data processing unit is disposed between a general-purpose host computer and a disk control unit. The data processing unit performs editing of pages (data) read out from a database efficiently. This data processing unit processes data-base access requirements for data stored in storage devices under the control unit. This configuration requires to define the data processing unit with hardware configuration definition and assign its unit address at system generation. Also, when a processing program in the host computer utilizes functions of the data processing unit, the processing program has to check the hardware configuration to confirm that a disk storage device to be accessed is connected to the data processing unit via disk control unit, and then issue access requests with the address of the data processing unit.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a data processing method and system which are capable of connecting a data processing unit at an arbitrary time without making a processing program which issues an access request take into account a connection condition of an input/output unit.
The above-mentioned object is based on the following problems which have been recognized with respect to the prior art:
As described above, the configuration of placing a data processing unit between a host computer and a control unit implies problems in the following aspects:
(a) Since it is necessary to previously define a connection configuration of the data processing unit and a unit address thereof, an operating system (OS) must be generated every time the data processing unit is introduced and is cut from the configuration.
(b) A processing program utilizing functions of the data processing unit first determines whether or not data to be accessed is stored in a disk storage device under the control unit connected to the data processing unit, so that it is necessary to check a connection relation of the input/output unit which was defined at the stage of the system generation.
(c) A processing program when utilizing functions of a data processing unit, designates the address of the data processing unit, and designates the address of a control unit when not utilizing the same, so that it is necessary to change the address depending on a unit to be utilized by the processing program, even if identical data is to be accessed.
To achieve the aforementioned object, the data processing unit is connected to the control unit, not to the host computer in a preferred embodiment of the present invention. On the assumption of such a configuration:
(1) The control unit includes a connection control module which permits the control unit to be connected with the data processing unit at an arbitrary time. The control unit, when receiving a data access request from a processing program of the host computer, requests the data processing unit to execute processing if the data processing unit is connected to the control unit. The data processing unit reads pages from a disk of an input/output unit connected to the control unit, selects records (data) required by the processing program and transfers the selected records to the processing program. When the data processing unit is not connected to the control unit, the control unit transfers pages to the host computer;
(2) The data processing unit includes a page edit module which manages information indicating that the data processing unit processes this page, and information indicative of the presence or absence of records requested by the processing problem in each page; and
(3) The host computer includes a record interface module which examines a page transferred from the control unit, and extracts records requested by the processing program from the transferred page and delivers the extracted records to the processing program when it is detected that the transferred page has been edited by the page edit module provided in the data processing unit.
The present invention achieves its object by means of a collaboration of the connection control module in the control unit, the page edit module in the data processing unit and the record interface module in the host computer. More specifically, (1) the connection control module in the control unit permits the control unit to be connected with the data processing unit at an arbitrary or optional manner. Then, in response to a request from a processing program, the control unit requests the data processing unit to perform processing if the data processing unit is connected to the control unit, whereas the control unit transfers data in page units to the host computer if the data processing unit is not connected thereto.
(2) The page edit module in the data processing unit, when receiving a processing request after the data processing unit is connected with the control unit, selects records requested by a processing program, stores information indicative of the presence or absence of the requested records in a page, and transfers the page to the control unit.
(3) The record interface module in the host computer examines a page transferred from the control unit, and extracts records requested by the processing program from the transferred page and delivers the extracted records to the processing program based on information stored by the page edit module in the data processing unit.
Thus, even if the data processing unit is connected or disconnected at an arbitrary time, a data access request can be normally processed, whereby the user need not pay attention to the connecting condition of the data processing unit.
BRIEF DESCRIPTION OF THE DRAWINGS
The objects and features of the invention will best be understood from a detailed description of preferred embodiments thereof, selected for purposes of illustration and shown in the accompanying drawings, in which:
FIG. 1 is a block diagram showing a data processing system according to a first embodiment of the present invention;
FIGS. 2A and 2B are diagrams showing the structures of page data processed by the system of FIG. 1;
FIG. 3 is a functional diagram of the control unit and the data processing unit shown in FIG. 1;
FIG. 4 is a diagram roughly showing an operation of a physical address generator;
FIG. 5 is a diagram showing a data format of a channel command word;
FIG. 6 is a diagram roughly showing the operation of a channel command generator;
FIG. 7 is a flowchart showing the processing of a channel interface of the first embodiment;
FIG. 8 is a flowchart showing the processing of a connection controller of the same;
FIG. 9 is a flowchart showing processing of an input/output selector;
FIG. 10 is a flowchart showing processing of a disk interface;
FIG. 11 is a functional block diagram of a data processing system according to a second embodiment of the present invention;
FIG. 12 is a functional block diagram of a DBMS and a data access program used in the system shown in FIG. 11;
FIG. 13 is a functional block diagram of a control unit and a data processing unit used in the system shown in FIG. 11;
FIG. 14 is a diagram showing the structure of data stored in a disk;
FIG. 15 is a diagram showing the structure of data stored in an input buffer arranged in the data processing unit;
FIG. 16 is a diagram roughly showing the operation of an operation request generator;
FIG. 17 is a flowchart showing the basic operation of the DBMS;
FIG. 18 is a flowchart showing the processing of the operation request generator;
FIG. 19 is a diagram roughly showing the operation of a relative byte address generator;
FIG. 20 is a flowchart showing the processing of the relative byte address generator;
FIG. 21 is a flowchart showing the processing of a reception area assigning unit;
FIG. 22 is a diagram roughly showing the operation of the reception area assigning unit;
FIG. 23 is a flowchart showing the processing of a data access program;
FIG. 24 is a flowchart showing the processing of the physical address generator;
FIG. 25 is a diagram roughly showing the operation of a channel command generator;
FIG. 26 is a flowchart showing the processing of the channel command generator;
FIG. 27 is a diagram showing a format of a unit address;
FIG. 28 is a table showing the relationship between data movements and inputted signals;
FIG. 29 is a flowchart showing the processing of the channel interface;
FIG. 30 and FIGS. 31A and 31B are flowcharts showing the processing of a data control unit controller;
FIG. 32 is a flowchart showing the processing of a disk controller;
FIG. 33 is a flowchart showing the processing of an input/output selector;
FIGS. 34, 35 and 36 are timing charts showing the operations of respective units used in the data processing system;
FIG. 37 is a diagram roughly showing an operation unit;
FIG. 38 is a diagram roughly showing the operation of a record selector;
FIG. 39 is a diagram roughly showing the operation of a record editor;
FIG. 40 is a flowchart showing the processing of a page determining unit;
FIG. 41 is a flowchart showing the processing of the record selector;
FIG. 42 is a flowchart showing the processing of the record editor;
FIG. 43 is a processing flowchart of a channel command generator showing a third embodiment of the present invention;
FIGS. 44A and 44B are flowcharts showing the processing of a channel interface used in the third embodiment;
FIGS. 45A and 45B are flowcharts showing the processing of a data processing unit controller used in the third embodiment;
FIG. 46 is a flowchart showing the processing of a disk controller used in the third embodiment;
FIG. 47 is a flowchart showing the processing of an input/output selector used in the third embodiment; and
FIGS. 48, 49 and 50 are timing charts showing the operations of respective units used in the data processing system of the third embodiment.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Embodiments of the present invention will hereinbelow be explained in detail with reference to the accompanying drawings.
FIG. 1 shows the whole configuration of a data processing system of a first embodiment.
In FIG. 1, reference numeral 5 designates a general-purpose host computer (a central processing unit), 1 a channel connected to the host computer 5, 2 a control unit connected to a disk (databases) 4 for controlling the disk 4 as well as input/output of data, 3 a data processing unit connected to the control unit 2, and 4 the disk for storing databases. Arrows illustrated between respective units indicate data paths while single lines indicate paths through which commands and control information are transferred.
In this embodiment, the host computer 5 includes a database management system (DBMS) 6 for issuing a data operation request to the data processing unit 3 and executes a processing program 20 for issuing a data processing request to the DBMS 6.
The DBMS 6 comprises a record selector 6g, a record editor 6h and a record interface 6i. The control unit 2 comprises a connection controller 2f, while the data processing unit 3 comprises a page editor 3e.
The DBMS 6 receives a data processing request from the processing program 20, analyzes the data processing request, and generates search condition information (conditions for record selection) and an edit condition information (directions for editing the selected records). Next, the DBMS 6 calculates the physical address of data in the database (the address of each page to be read) and generates physical address information (address). The DBMS 6 also reserves a buffer area necessary for reading the data and generates a buffer list including buffer addresses. Subsequently, the DBMS 6 issues a data operation request to the control unit 2 with the search condition information, the physical address information and the buffer list described above. The control unit 2 read pages from the disk 4.
The connection controller 2f of the control unit 2 transfers each page from the disk 4 to the data processing unit 3 if the data processing unit 3 is connected to the control unit 2. If the data processing unit 3 is not connected to the control unit 2, the connection controller 2f transfers the pages to the DBMS 6 directly.
The page editor 3e of the data processing unit 3, when receiving the page that includes records from the control unit 2, invalidates the records which do not satisfy the search condition describing which records are to be selected. The page editor 3e also writes in the page information indicating that the data processing unit 3 process this page, and stores the page in the buffer pointed by each entry of the buffer list through the control unit 2. If all records in the page do not satisfy the search condition, the page editor 3e writes in the page information indicating that requested data does not exist in this page to prevent DBMS 6 from processing records in this page later again.
The record interface 6i of the DBMS 6 examines the page stored in the buffer, and determines whether this page is edited (records which do not satisfy the search condition have been selectively invalidated) by the page editor 3e or not. The record interface 6i delivers the page to the record editor 6h, if the page has been edited. If it has not been edited, the record interface 6i delivers it to the record selector 6g. If the edited page does not include records that satisfy the search condition, the record interface 6i proceeds to process the next page (a page stored in the next buffer). The record selector 6g, when receiving the page from the record interface 6i, invalidates records which do not satisfy the search condition in the page, and delivers the page to the record editor 6h. The record editor 6h, when receiving the page from the record interface 6i or the record selector 6g, edits selected records stored in the received page in accordance with an edit condition information, and delivers the result to the processing program 20.
By the above-mentioned operation, the processing program 20 need not pay attention to whether or not the data processing unit 3 is connected to the control unit 2 at issuing a data processing request.
The page editor 3e may mark records for indicating that they satisfy the search condition. But, in the present embodiment, we assume that the page editor 3e invalidates records that do not satisfy the search condition.
FIGS. 2A and 2B are explanatory diagrams of a page configuration and the processing performed by the page editor 3e of the data processing system of the present embodiment.
In FIG. 2A, reference 5a designates a page, 5b a control information field for managing the use of the page 5a, 5c records, and 5d slots for pointing the records 5c.
Suppose that five records L1, L2, L3, L4 and L5 are stored in the page 5a, as shown in the drawings and that the records L2 and L4 do not satisfy the search condition. The page editor 3e, as shown in FIG. 2A, sets slots pointing the records L2 and L4 to an unused state, changes the control information field 5b to indicate that this page is edited (cutting the corner), and transfers the page 5a to the DBMS 6 through the control unit 2. If no records satisfy the search condition, the page editor 3e changes the control information field 5b to indicate that requested records do not exist in the page (cutting both corners) as shown in FIG. 2B.
The record interface 6i determines whether the transferred page 5a is a page edited by the data processing unit 3, and whether it includes requested records by referring the control information field 5b, and delivers the page 5a to the record selector 6g or the record editor 6h.
FIG. 3 shows in detail the control unit 2 and the data processing unit 3 appearing in FIG. 1.
Here, a detailed description will be given of the feature of the invention that the data processing unit 3 can be connected to the control unit 2 at an arbitrary time. The control unit 2 is composed of (a) the connection controller 2f, (b) a channel interface 2c for receiving a channel command, (c) a disk interface 2g for accessing data by driving the disk 4, (d) the input/output selector 2d for switching input/output of data in accordance with a connecting state of the data processing unit 3 (connected or disconnected), and (e) a physical address buffer 2e for storing physical address information of data.
The data processing unit 3 is composed of (a) the page editor 3e, (b) an input buffer 3b, (c) an output buffer 3d for storing the edited result, (d) a condition buffer 3c for keeping conditions necessary to edit, and (e) control unit interface 3f for controlling data inputted to and outputted from the respective buffers.
In FIG. 3, data paths between the above-mentioned elements are represented by thick lines and control paths by thin lines.
FIG. 5 shows the structure of a channel command word which is issued by the channel 1 to the control unit 2 shown in FIG. 1.
A channel command word 10 is composed of a command code 10d, a data address field 10e and a count field 10f.
FIG. 6 illustrates how a channel command word chain is generated by a channel command generator 7a (not shown in FIG. 1) disposed between the DBMS 6 and the channel 1 shown in FIG. 1.
The channel command generator 7a, upon receiving an input/output request from the DBMS 6, generates a channel command word chain and delivers this chain to the channel 1. More specifically, the channel command generator 7a receives search condition information 11b, physical address information 13 and an assigned buffer list 14, generates a search condition transfer command 10a for transferring the search condition information 11b, a physical address transfer command 10b for transferring the physical address information 13, and a data input command 10c, and forms a chain of these commands in the order shown in FIG. 6. In this example, the chain includes three data input commands 10c. The command chain word 10a positioned at the head of the chain is the search condition transfer command 10a for transferring the search condition information. The channel interface 2c, upon receiving this command, starts the connection controller 2f in a search condition information transfer mode.
FIG. 7 is a flowchart showing the operation of the channel interface 2c provided in the control unit 2 while FIG. 8 a flowchart showing the operation of the connection controller 2f.
The channel interface 2c, upon receiving the search condition information command 10a for transferring the search condition information, first analyzes the command (step 301), starts the connection controller 2f (step 302), and waits for the connection controller 2f to complete its operation (step 303), as shown in FIG. 7.
The connection controller 2f examines whether or not the data processing unit 3 is connected to the control unit 2 (step 314) as shown in FIG. 8. If it is connected (step 315), the connection controller 2f starts the control unit interface 3f and the input/output selector 2d of the data processing unit 3 in a search condition information transfer mode (steps 316, 317). Then, the connection controller 2f waits for a report from the data processing unit 3 (step 318), and informs the channel interface 2c that a condition transfer has been completed (step 319). On the contrary, if the data processing unit 3 is not connected to the control unit 2 (step 315), the connection controller 2f starts the input/output selector 2d in an unconnected mode (step 320), and informs to the channel interface 2c that a condition transfer has been completed (step 312).
FIG. 9 is a flowchart showing the operation of the input/output selector 2d disposed in the control unit 2, and FIG. 10 the operation of the disk interface 2g.
The input/output selector 2d transfers data from the channel 1 to the data processing unit 3 (step 332) if in the search condition information transfer mode (step 330), and abandons the search condition information 11b from the channel 1 (step 333) if in the unconnected mode. Then, after informing the connection controller 2f of a data transfer (step 336), the connection is released (step 337). By the above-mentioned operation, if the data processing unit 3 is connected to the control unit 2, the search condition information is transferred to the condition buffer 3c, whereas if it is not connected, the search condition information is abandoned at the input/output selector 2d.
Turning back to FIG. 6, the physical address transfer command 10b, which is the next channel command word, is generated to transfer the physical address information 13, so that the channel interface 2c, upon receiving this command (step 301), starts the connection controller 2f and the disk interface 2g in a physical address transfer mode, as shown in FIG. 7 (steps 304, 305).
The connection controller 2f starts the input/output selector 2d in the physical address transfer mode and transfers the physical address information to the physical address buffer 2e, as shown in FIG. 8 (steps 313, 322). The input/output selector 2d couples the channel 1 with a data path to the physical address buffer 2e (steps 330, 334) and informs the connection controller 2f of a data transfer (step 336), as shown in FIG. 9.
When a transfer of the physical address information has been completed, the disk interface 2g issues a data transfer request to the disk 4 (step 339) with reference to the physical address buffer 2e, positions a read head of the disk (step 339), and informs that the positioning has been terminated (step 340), as shown in FIG. 10.
Turning back again to FIG. 6, the data input command 10c is transferred from the channel 1 to the channel interface 2c of the control unit 2. The channel interface 2c, when receiving the page input command 10c, which is the next channel command word (step 301), once releases the coupling with the channel (step 306) and waits for an inform of positioning termination from the disk 4 (step 307), as shown in FIG. 7. Then, the channel interface 2c, when receiving the inform of positioning termination from the disk 4, starts the connection controller 2f (step 308), waits for the connection controller 2f to complete its operation (step 309), couples again the channel 1 (step 310), and transfers data (step 311). By performing this operation, the disk interface 2g is coupled again to the channel 1 and informs the channel interface of the completion of positioning (steps 338, 341), as shown in FIG. 10. In this event, if the data processing unit 3 is not connected to the control unit 2, the connection controller 2f starts the input/output selector 2d in a normal mode (step 324). On the contrary, if the data processing unit 3 is connected to the control unit 2, the connection controller 2f starts the control unit interface 3f and the input/output selector 2d in a data input mode (steps 326, 327), receives an inform of page edit completion from the data processing unit 3 (step 328), and informs the channel interface 2c of the page edit completion (steps 325, 329). Thus, if the data processing unit 3 is connected, the page is once delivered to the data processing unit 3 for edit and then transferred to the channel 1, whereas, if the data processing unit 3 is not connected, the page is directly transferred from the disk 4 to the channel 1.
Also, if the data processing unit 3 is connected in course of executing a channel command word chain, the connection controller 2f stores a connecting state of the data processing unit 3 when it receives a search condition transfer command 10a, and inhibits a page from being transferred to the data processing unit 3 until the channel command word chain is terminated. On the contrary, when the data processing unit 3 is to be disconnected, the connection controller 2f recognizes a disconnect request and inhibits a page from being transferred to the data processing unit 3 after receiving the disconnect command even if the data processing unit 3 is connected to the control unit 2. If the connection controller 2f receives a request for disconnecting the data processing unit 3 in course of executing a channel command word chain, it outputs a message for delaying the disconnection until the execution of the channel command word chain is terminated. It is thought that the disconnection request is transmitted from a console through the host computer 5 to the connection controller 2f of the control unit 2 and the data processing unit 3 is disconnected by means of a switch arranged on the frame of the control unit 2, or the disconnection request is transmitted from the control unit interface 3f to the connection controller 2f and the data processing unit 3 is disconnected by means of a switch arranged on the frame of the data processing unit 3. Either of these methods may be employed. Thus, the data processing unit 3 can be connected to and disconnected from the control unit 2 at any time.
Next, a second embodiment of the present invention will be explained.
FIG. 11 is a block diagram showing a general configuration of a data processing system according to the second embodiment of the invention.
In the second embodiment, the processing of a host computer 5 and a DBMS 6 will be described.
Here, the DBMS (database management system) 6 is exemplified as a program which issues a data operation request to a data processing unit 3.
In FIG. 11, reference numeral 5 designates the host computer (central processing unit), 1 a channel disposed on the host computer side for performing input/output control, 7 a data access program, 3 the data processing unit, 4 a disk for storing a database, 2 a control unit for controlling the disk 4 to input and output data to and from the disk 4, 8 a directory information file provided for the DBMS 6 to manage the database, and 9 an extent information file provided for the data access program to manage pages stored in the disk 4. The DBMS 6 is also provided with a page determining unit 6a, the data access program 7 with a channel command generator 7a, and the control unit 2 with a data processing unit controller 2a.
FIG. 12 is a functional block diagram of the DBMS and the data access program, and FIG. 13 is a block diagram showing the configurations and functions of the control unit and the data processing unit.
As shown in FIG. 12, the DBMS 6 is provided with an operation request generator 6b, a relative byte address generator 6c, a reception area assigning unit 6d, a record selector 6e and a record editor 6f, in addition to the above-mentioned elements. The data access program 7 in turn is provided with a physical address generator 7b, in addition to the above-mentioned elements.
The control unit 2, as shown in FIG. 13, is provided with a disk controller 2b, a channel interface 2c, an input/output selector 2d, and a physical address buffer 2e, in addition to the element mentioned above.
The data processing unit 3 is provided with an operation unit 3a, an input buffer 3b, an output buffer 3d and a condition buffer 3c.
An outline of the processing performed by the data processing unit 3 will be described with reference to FIG. 12. Upon receiving a search request 11 from the user, the operation request generator 6b of the DBMS 6 analyzes the search request 11 and as the results obtains search area information 11a describing which page is to be searched, search condition information describing which data is to be selected in the page, and edit condition information 11c describing in which form searched data is to be edited. The relative byte address generator 6c converts the search area information 11a to a list 12 of relative byte address which represents relative byte addresses expressed by logical addresses in a list form and indicates in which area of the disk is to be searched, with reference to directory information 8 describing the relationship between a relative address serving as an identifier of a page and a physical address on the disk 4. The reception area assigning unit 6d receives the list 12 of relative byte address generated by the relative byte address generator 6c, determines the number of reception areas to maintain necessary areas, and generates an assigned buffer list 14 for releasing unused areas after a data transfer has been completed. The page determining unit 6a determines, after a data transfer has been completed, determines from a transferred page whether or not the data processing unit 3 has operated. If it is determined that the data processing unit 3 has not operated, the record selector 6e and the record editor 6f are called to perform selection and edit. On the contrary, if it is determined that the data processing unit 3 has operated, the record editor 6f only is called.
FIG. 14 illustrates how a database is stored in the disk 4 shown in FIG. 13.
In the present embodiment, an SQL (Structured Query Language) is used as a search request 11. The SQL is a language which is specified as described in "An Introduction to Database Systems", C. J. Date, Vol. 1, Fourth Edition. FIG. 14 shows how the database is stored in the disk and how the database is processed by the SQL. A database is composed of a plurality of pages 41, each page 41 is composed of a plurality of records 41a, and each record 41a is composed of a plurality of columns 41b.
The search request 11 of this embodiment shows a case where all records in a table T1 are read from the disk records which include the value "F" (female) in third column C3 (SEX) are selected (based on the search condition), and the second (NAME), fourth (AGE) and sixth (SECTION) columns of the selected records are edited (based on the edit condition) and outputted.
Turning back to FIG. 12, the physical address generator 7b of the data access program 7 converts the list 12 of relative byte address from the DBMS 6 to physical address information 13 referring to extent information 9 describing mapping information between the relative byte addresses and the physical addresses. The channel command generator 7a generates from the search condition information 11b produced by the DBMS 6, the assigned buffer list 14 and the physical address information 13 generated by the physical address generator 7b a command (channel command word) which is to be transferred to the data processing unit 3.
In FIG. 13, the channel interface 2c of the control unit 2 starts the data processing unit controller 2a by a control signal generated from the channel 1 and returns the control to the channel 1 by an inform of termination from the data processing unit controller 2a. The data processing unit controller 2a in turn starts the disk controller 2b, the input/output selector 2d, and the operation unit 3a of the data processing unit 3 by a starting signal generated from the channel interface 2c to perform the control of the data processing unit 3.
The disk controller 2b controls the disk 4 by a starting signal generated from the data processing unit controller 2a. The input/output selector 2d selects a data path by a starting signal generated from the data processing unit controller 2a.
The operation unit 3a of the data processing unit 3, by a starting signal generated from the data processing signal controller 2a, processes data transferred to the input buffer 3b with reference to the condition buffer 3c and transfers the thus processed data to the output buffer 3d.
FIG. 16 illustrates an outline of the processing performed by the operation request generator 6b of FIG. 12, and FIGS. 17 and 18 are flowcharts of processing performed by the DBMS and the operation request generator, respectively.
As shown in FIG. 16, upon receiving a search request 11 from the user, the operation request generator 6b of the DBMS 6 converts the received search request 11 to the search area information 11a, the search condition information 11b and the edit condition information 11c.
In the example shown in FIG. 16, it is assumed that the search request 11 has been issued to search a table T1, select records in which "F" is written in the third column C3 thereof, and edit the second, fourth and sixth columns C2, C4 and C6 from these searched records. Then, a formula C3=`F` is produced as the search area information 11b while C2, C4 and C6 are produced as the edit condition information 11c.
This operation is shown in FIG. 17 as the processing performed by the operation request generator at step 101 and corresponds to processing at step 106 for resolving a search request into phrases and paragraphs and processing at step 107 for generating search area information and search condition information, both performed by the operation request generator as shown in FIG. 18.
Next, the DBMS 6 transfers the control to the relative byte address generator 6c for converting the search area information 11a generated by the operation request generator 6b to the list 12 of relative byte address. The relative byte address generator 6c refers to the directory information 8, generated when the DBMS 6 produces a database, for managing mapping information between a table and a logical address to convert the search area information 11a to the list 12 of relative byte address.
FIG. 19 illustrates an outline of the processing performed by the relative byte address generator 6c shown in FIG. 12.
It is assumed in this embodiment that each address in the list 12 of relative byte address is given by RBA (Relative Byte Address) which represents a relative position from the first record of data, and tables T1 and T2 have been produced on the database.
When the table T1 is inputted as the search area information 11a, RBA1, RBA2 and RBA3 are extracted to an address list field 12b in the list 12 of relative byte address, and the number of addresses in the list or "3" in this case is inputted to a list count field 12a. This operation is shown in FIG. 17 as the processing performed by the relative byte address generator at step 102 which corresponds to processing at steps 108 to 113 in FIG. 20.
More specifically, the relative byte address generator, started at step 102, inputs the search area information (step 108) and searches the directory information (step 109) to determine whether or not the directory information has been completely examined (step 110). If it is determined that the directory information has been examined, the processing is terminated. If the table information column is coincident with the table name (step 111), the RBA written in the RBA column is registered in the list of relative byte address (step 112), and the next table information column is examined (step 113).
FIG. 22 illustrates an outline of the processing performed by the reception area assigning unit shown in FIG. 12.
The DBMS 6 transfers the control to the reception area assigning unit 6d for assigning a reception area necessary for executing a search request. The reception area assigning unit 6d first sets the number of assigned buffers to the same number as that of addresses registered in the list 12 of relative byte address by referring to the list count field 12a (see FIG. 19) of the list 12 of relative byte address. Next, a request number 16 is designated which is unique in the DBMS as an identifier of the search request 11. Then, referring to a buffer manage table 15, a number of buffers, determined by unassigned buffers, are reserved, and the addresses of the reserved buffers are extracted to the assigned buffer list 14.
In FIG. 22, there are prepared ten buffers, wherein the first, third and fifth buffers have been assigned to the request number 1 while the sixth, eighth and tenth buffers have been assigned to the request number 2, and the request number 3 is requesting three buffers. As a result, by searching the buffer manage table 15 from the top as shown in FIG. 22, unassigned second, fourth and seventh buffers are assigned to the request number 3, buffer addresses AD2, AD4 and AD7 are stored in the address list field 14b of the assigned buffer list 14, and the number of assigned buffers is stored in the list count field 14a.
The above-mentioned operation corresponds to the processing at steps 114 to 119 performed by the reception area assigning unit started at step 103 in FIG. 21. More specifically, in FIG. 21, the reception area assigning unit receives the reserved number of buffers for storing the request IDs 16 (step 114), determines whether or not the designated number of buffers have been reserved (step 115), and further determines whether or not an assigned ID field in the buffer manage table is zero (step 116) if it is determined at step 115 that the designated number of buffers have not been reserved. If zero is stored the assigned ID field in the buffer manage table, the request ID is stored therein (step 118), and then the address in the buffer address field is written into the assigned buffer list 14. On the contrary, if the assigned ID field contains a number other than zero (step 116), the next ID is searched (step 117).
The DBMS 6 thereafter issues a search request to the data access program 7, which is processing shown in FIG. 17 as "issue of I/O" at step 104.
The data access program 7, upon receiving the search request from the DBMS 6, transfers the control to the physical address generator 7b.
FIG. 4 illustrates an outline of the processing performed by the physical address generator 7b shown in FIG. 12.
The physical address generator 7b converts the list 12 of relative byte address generated by the DBMS 6 to physical address information 13 where each relative byte address in the list 12 is converted to a corresponding physical address on the basis of the extent information 9.
In the example shown in FIG. 4, it is assumed that three RBA1, RBA2 and RBA3 are inputted as relative byte addresses stored in the list 12, and physical addresses corresponding to these relative byte addresses CCHHR1, CCHHR2 and CCHHR3 are generated.
FIG. 23 illustrates a processing flow of the data access program, and FIG. 24 that of the physical address generator.
In FIG. 23, the data access program, after completing the processing of the physical address generator (step 135), executes the processing of the channel command generator 136. Here, the step 135 relates to the physical address generation processing.
In FIG. 24, it is determined whether or not the RBA still exists in the list 12 of relative byte address (step 137). If the RBA exists, it is extracted (step 130). Then, the next RBA is examined (step 140).
The data access program 7 next transfers the control to the channel command generator 7a which generates a data operation request command group for starting the control unit 2 (step 136), as shown in FIG. 23.
FIG. 25 illustrates an outline of the processing performed by the channel command generator 7a shown in FIG. 12.
The channel command generator 7a receives the physical address information 13 generated by the physical address generator 7b, the search condition information 11b received from the DBMS 6 and the assigned buffer list 14 to produce a group of data operation request commands.
In the example shown in FIG. 25, it is assumed that the channel command generator 7b receives all of the physical address information 13, the search condition information 11b and the assigned buffer list 14, where three buffers are assigned as shown in FIG. 22 and AD2, AD4 and AD7 are stored in the assigned buffer list 14 as the addresses of the assigned buffers.
FIG. 26 is a flowchart of the processing performed by the channel command generator.
The processing of the channel command generator shown as the step 136 in FIG. 23 is composed of, as shown in FIG. 26, generating a search condition transfer command from the search condition information (step 141), determining whether or not all the physical address information has been processed (step 142), and generating the physical address transfer command from the physical address information if all the physical address information has not been processed (step 144). If all the physical address information has been processed, the processing is terminated.
As the data operation request command, the channel command word (CCW) is employed in this embodiment. As described above, FIG. 5 shows the data format of the channel command word 10 which is composed of the command code 10d, the data address field 10e and the count field 10f.
Next, explanation will be given of the collective operations of the channel 1, the control unit 2, the data processing unit 3 and the disk 4.
First, the interface between the channel 1 and the control unit 2 will be described in detail. The channel 1, upon receiving a channel command word group from the data access program, transfers the unit address 12 to the control unit 2 as a starting signal.
FIG. 27 is a format of the unit address 12; FIG. 28 a table showing the relationship between signals inputted to the input/output selector and movement and type of data; FIG. 29 is a flowchart of the operation performed by the channel interface; FIGS. 30, 31A and 31B flowcharts of the operation performed by the data processing unit controller; FIG. 32 a flowchart of the operation performed by the disk controller; and FIG. 33 a flowchart of the operation performed by the input/output selector.
The unit address 12, as shown in FIG. 27, is composed of a control unit address 12a and an address 12b of a disk which records data to be extracted.
Control unit 2 first checks the control unit address 12a (step 145 shown in FIG. 29), further checks the disk address 12b (step 146), and is coupled to the channel 1 if both addresses are coincident (step 147). The channel 1, when coupled to the control unit 2, transfers a command code 10a as a start signal to the control unit 2.
When the channel 1 is coupled to the control unit 2 by the above procedure (step 147), the channel interface 2c is set into a command input waiting state (step 148).
The channel command word group inputted from the channel 1 is composed of a search condition transfer command 10a, a physical address transfer command 10b and a data input command 10c, and these commands are started by the channel 1 in this order.
(i) First, the channel interface 2c, when recognizing the search condition transfer command 10a (step 149 shown in FIG. 29), starts the data processing unit controller 2a in a condition transfer mode (step 153).
The data processing unit controller 2a checks the connection of the data processing unit 3 (step 164 shown in FIG. 30), and if the data processing unit 3 is connected to the control unit 2, the data processing unit controller 2a starts the operation unit 3a and the input/output selector 2d in the condition transfer mode (steps 165, 166), and waits for informs from the operating unit 3a and the input/output selector 2d (steps 167, 168).
The input/output selector 2d, on the other hand, when the search condition is transferred thereto (steps 195, 198), informs the data processing unit controller 2a of a search condition (step 197), while the operation unit 3a recognizes that the search condition has been transferred to the condition buffer 3c and informs a receipt of a search condition. This is the operation performed by the input/output selector 2d when a condition output signal is inputted, as shown in FIG. 28.
The data processing unit controller 2a receives the informs from the input/output selector 2d and the operating unit 3 (steps 16, 168 shown in FIG. 30), and informs the channel interface 2c of an output of the search condition (step 169 in FIG. 30 and steps 154, 155 in FIG. 29).
If it is detected that the data processing unit 3 is not connected to the control unit 2 (steps 163, 164 shown in FIG. 30), the data processing unit controller 2a starts the input/output selector 2d in the condition transfer mode (step 170) and waits for an inform from the input/output selector 2d (step 171).
The input/output selector 2d, when the search condition is transferred thereto, informs the data processing unit controller 2a of a search condition (steps 195, 198, 199, 197 shown in FIG. 33). This is the operation performed by the input/output selector 2d when the condition output signal is inputted, as shown in FIG. 28.
The data processing unit controller 2a, upon receiving the inform from the input/output selector 2d, informs the channel interface 2c of the search condition output (steps 171, 169 in FIG. 30 and steps 54, 155 in FIG. 29).
(ii) Next, the channel interface 2c, when recognizing the physical address transfer command 10b, starts the data processing unit 2a in a physical address transfer mode (steps 148, 149, 150 shown in FIG. 29).
The data processing unit controller 2a starts the input/output selector 2d in the physical address transfer mode and waits for an inform from the input/output selector 2d (step 163 in FIG. 30 and steps 186, 187 in FIG. 31).
The input/output selector 2d, when the physical address information is transferred thereto, informs the data processing unit controller 2a of a physical address information transfer (steps 195, 198, 200, 201, 197 shown in FIG. 33). This is the operation performed by the input/output selector 2d when a physical address signal is inputted, as shown in FIG. 28.
The data processing unit controller 2a, upon receiving the inform of physical address information transfer, starts the disk controller 2b (steps 187, 188 shown in FIG. 31B).
The disk controller 2b controls the disk 4 to position a read head (steps 191, 192 shown in FIG. 32), and then, when receiving an inform of read head positioning termination, informs the data processing unit controller 2a of a positioning termination (step 189).
The data processing unit controller 2a, upon receiving the inform from the disk controller 2b (step 189 in FIG. 31B), informs the channel interface 2c of the positioning termination (step 190 in FIG. 31B and steps 151, 152 in FIG. 29).
(iii) Next, the channel interface 2c, when recognizing the data input command 10c (steps 148, 149 shown in FIG. 29), starts the data processing unit controller 2a in a data input mode (step 156).
The data processing unit controller 2a checks the connection of the data processing unit 3 (steps 163, shown in FIG. 30), and if the data processing unit 3 is connected to the control unit 2, the data processing unit controller 2a starts the operation unit 3a, the input/output selector 2d and the disk controller 2b in the data input mode and waits for informs from the operation unit 3a and the input/output selector 2d and the disk controller 2b (steps 173, 174, 174-1, 175, 176 shown in FIG. 10).
The input/output selector 2d, when data is inputted thereto (steps 195, 198, 200, 202 shown in FIG. 33), informs the data processing unit controller 2a of a data input (step 197). This is the operation performed by the input/output selector 2d when a data input signal is inputted, as shown in FIG. 28.
The operation unit 3a recognizes that the data has been transferred to the input buffer 3b. Next, if a search condition has been inputted to the condition buffer 3c, the operation unit 3a selects data stored in the input buffer 3b in accordance with the search condition and transfers the result to the output buffer 3d. If the condition buffer 3c is not loaded with a search condition, data stored in the input buffer 3b is transferred as it is to the output buffer 3d, and the operation unit 3a informs the data processing unit controller 2a of a search termination. Thus, even if the data processing unit 3 is connected to the control unit 2 at an arbitrary time, a page transfer request can be normally performed.
The data processing unit controller 2a, upon receiving the informs from the input/output selector 2d and the operation unit 3a (steps 175, 176 as shown in FIG. 30), starts the input/output selector 2d in a data output mode (step 177) and waits for an inform of termination from the input/output selector 2d (step 178).
The input/output selector 2d recognizes the data output (steps 195, 198, 200, 202) and informs the data processing unit controller 2a of an data output (steps 204, 197). This is the operation performed by the input/output selector 2d when a data output signal is inputted, as shown in FIG. 28. The data processing unit controller 2a thus informs the channel interface 2c of the data output (steps 178, 179 in FIG. 30 and steps 157, 158 in FIG. 29). On the contrary, if the data processing unit 3 is not connected to the control unit 2 (steps 183, 184 shown in FIG. 30), the data processing unit controller 2a starts the input/output selector 2d without input signal and waits for an inform from the input/output selector 2d (steps 183, 184 shown in FIG. 31A).
The input/output selector 2d, when data is transferred, informs the data processing unit controller 2a of a data output (steps 195-197 shown in FIG. 33). This is the operation performed by the input/output selector 2d when no signal is inputted, as shown in FIG. 28.
The data processing unit controller 2a, upon receiving the inform from the input/output selector 2d (step 184 shown in FIG. 31A), informs the channel interface 2c of the data output (step 185 in FIG. 31A and steps 157, 158 in FIG. 29).
(iv) The above described processing (ii) and (iii) are respectively repeated twice.
FIGS. 34, 35 and 36 are timing charts of the control unit and the data processing unit in respective starting conditions. More specifically, FIG. 34 shows a case where the starting condition is a condition output, wherein the operation unit 3a and the input/output selector 2d are both started when the data processing unit 3 is connected to the control unit 2 while the input/output selector 2d is solely started when it is not connected. FIG. 35 shows a case where the starting condition is a physical address transfer, wherein the input/output selector 2d is started when the data processing unit 3 is connected while the disk controller 2b is started when it is not connected. Further, FIG. 36 shows a case where the starting condition is a data input, wherein the operation unit 3a, the input/output selector 2d and the disk controller 2b are all started when the data processing unit 3 is connected to the control unit while the input/output selector 3d is solely started when it is not connected.
By thus controlling the operation unit 3a, the input/output selector 2d and the disk controller 2b, it is possible to request the data processing unit 3 to perform processing when the data processing unit 3 is connected to the control unit 2 and only perform a page transfer when it is not connected.
Next, the processing of the operation unit 3a provided in the data processing unit 3 will be described in detail.
FIG. 15 illustrates a page structure of data stored in the input buffer of the data processing unit, and FIG. 3 an outline of the processing performed by the operation unit 3a.
Data stored in the input buffer 3b has a page structure as shown in FIG. 15 such that a record 41a can be traced by a slot 41d which indicates an offset value from the head of a page 41. The slot 41d is positioned in front of a control block 41c positioned at the end of the page 41 for managing information in the page.
As shown in FIG. 37, the operation unit 3a, when started by the data processing unit controller 2a of the controller 2, takes out a search condition from the condition buffer 3c and selects records in the page stored in the input buffer 3b. In the example shown in FIG. 37, there exist four records in the page, three of which are records of man and only one of which is a record of woman. The search condition in the condition buffer 3c is C3=`F`, that is, the third column indicates that the record is of woman. Therefore, the first, third and fourth slots 41d are deleted, and the second record only remains, as shown in the drawing. Also, a search termination flag 41e in the control block 41c is set to "on" for informing the DBMS that the data processing unit 3 has operated.
Next, the processing of the DBMS 6 after a data transfer has been completed will be described in detail.
FIGS. 38 and 39 illustrate outlines of the processing performed by the record selector and the record editor shown in FIG. 12, respectively, and FIGS. 40, 41 and 42 are flowcharts respectively showing the processing performed by the page determining unit, the record selector and the record editor provided in the DBMS also shown in FIG. 12.
After data has been transferred, the control is given to the page determining unit 6a (step 105 shown in FIG. 17). The page determining unit 6a examines the assigned buffer list 14 (step 120 shown in FIG. 40) and refers to the search termination flag 41e included in the control block 41c in a page transferred to the buffer (steps 121, 122). If the search termination flag 41e is on, indicating that the data processing unit 3 has operated, the page determining unit 6a only starts the record editor 6f (step 124) and examines the next assigned buffer list (step 125). On the contrary, if the search termination flag is off (step 122), indicating that the data processing unit 3 has not operated, the page determining unit 6a calls the record selector 6g and the record editor 6f (steps 123, 124) and examines the next buffer list (step 125).
As shown in FIG. 38, the record selector 6e performs the same processing as that of the operation unit 3a shown in FIG. 37 (steps 123-130 shown in FIG. 41).
The record editor 6f, as shown in FIG. 39, refers to the edit condition information 11c and edits selected records in accordance with the edit condition information 11c (steps 132, 133 shown in FIG. 42) to accumulate search and edit results. In the example shown in FIG. 39, the edit condition information 11c includes C2, C4 and C6, which indicates the extraction of the second, fourth and sixth columns.
The above described operation enables the DBMS 6 to perform data search and edit without paying attention to whether or not the data processing unit 3 is connected to the control unit 2.
Next, a third embodiment of the present invention will be described.
The third embodiment differs from the second embodiment in that the latter comprises the channel command word interface which positions the read head every time a page is inputted while the former is provided with an interface which allows pages to be inputted in bulk such that a plurality of pages can be sequentially read out.
Such feature and operation of the third embodiment will be explained in detail with reference to FIGS. 16, 17 and 18 as well as FIG. 19 roughly illustrating the operation of the relative byte address generator, FIG. 20 illustrating the processing flowchart of the relative byte address generator, FIG. 21 illustrating the processing flow of the reception area assigning unit, and FIG. 22 roughly illustrating the operation of the reception area assigning unit.
The operation request generator 6b of the DBMS 6, when receiving a search request from the user, converts the search request to search area information 11a, search condition information 11b and edit condition information 11c (step 101 shown in FIG. 17). Next, the DBMS 6 transfers the control to the relative byte address generator 6c for converting the search area information 11a generated by the operation request generator 6b to the list 12 of relative byte address (step 102 shown in FIG. 17).
The relative byte address generator 6c examines directory information 8 generated when the DBMS 6 produces a database for managing mapping information between a table and a logical address as shown in FIG. 19 to convert the search area information 11a to the list 12 of relative byte address.
The DBMS 6 next transfers the control to the reception area managing unit 6d for assigning reception areas necessary to execute the search request (step 103 shown in FIG. 17). The reception area managing unit 6d, as shown in FIG. 22, first refers to a list count field 12a in the list 12 of relative byte address to prepare the same number of buffers as the number written therein. Next, the reception area managing unit 6d determines a request number 16, unique in the DBMS 6, as the identifier for this search request 11 (steps 116, 117 shown in FIG. 21). Then, referring to a buffer managing table 15, a number of buffers, determined by unassigned buffers, are reserved (steps 114, 115), and the addresses of the reserved buffers are extracted to the assigned buffer list 14 (steps 118, 119). The DBMS 6 thereafter issues a search request to the data access program 7 (step 104 shown in FIG. 17).
The above-mentioned operation will be further described in detail with reference to FIGS. 23 and 24 respectively illustrating the processing flow of the data access program and the physical address generator and FIG. 4 roughly illustrating the operation of the physical address generator.
The data access program 7, upon receiving the search request from the DBMS 6, transfers the control to the physical address generator 7b (step 135 shown in FIG. 23).
The physical address generator 7b, as shown in FIG. 4, converts the list 12 of relative byte address generated by the DBMS 6 to physical address information 13 where each relative byte address in the list 12 is converted to a corresponding physical address by extent information 9 (steps 135-140 shown in FIG. 24).
The data access program 7 next transfers the control to the channel command generator 7a which generates an operation request command group for starting the control unit 2 (step 136 shown in FIG. 23).
The operation performed by the channel command generator will be described with reference to FIG. 25 roughly illustrating the operation of the channel command generator and FIG. 26 illustrating the processing flow of the channel command generator.
The channel command generator 7a, as shown in FIG. 25, receives the physical address information generated by the physical address generator 7b, the search condition information received from the DBMS 6 and the assigned buffer list 14 to generate a data operation request command group from these received information (steps 141-144 shown in FIG. 26). In the example shown in FIG. 25, it is assumed that the channel command generator 7a receives all of the physical address information 13, the search condition information 11b and the assigned buffer list 14, assigns four buffers to the assigned buffer list 14 as shown in FIG. 22, and designates AD2, AD4 and AD6 to the assigned buffer addresses.
Next, outlines of the channel 1, the control unit 2, the data processing unit 3 and the disk 4 will be explained.
FIGS. 44A and 44B illustrate the processing flow of the channel interface provided in the control unit, FIGS. 45A and 45B that of the data processing unit controller, FIG. 46 that of the disk controller, and FIG. 47 that of the input/output selector.
First, the interface between the channel 1 and the control unit 2 will be described. The channel 1, upon receiving a channel command word group from the data access program 7, transfers a unit address 12 to the control unit 2 as a starting signal.
The unit address 12 is composed of a control unit address 12a and an address 12b of a disk which records data to be extracted. The channel interface of the control unit 2, as shown in FIG. 44A, first checks the control unit address 12a (step 205), further checks the disk address 12b (step 206), and is coupled to the channel 1 if both addresses are coincident (step 207). The channel 1, when coupled to the control unit 2, transfers a command code 10a as a start signal to the control unit 2. The channel command word group inputted from the channel 1 is composed of a search condition transfer command 10a, a physical address transfer command 10b and a data input command 10c, and these commands are started by the channel 1 in this order.
(i) First, the channel interface 2c, when recognizing the search condition transfer command 10a, starts the data processing unit controller 2a in a condition transfer mode (steps 208, 209, 210 shown in FIG. 44A).
The data processing unit controller 2a, as shown in FIG. 45B, checks the connection of the data processing unit 3 (step 237), and if the data processing unit 3 is connected to the control unit 2, the data processing unit controller 2a starts the operation unit 3a and the input/output selector 2d in the condition transfer mode (steps 238, 239), and waits for informs from the operation unit 3a and the input/output selector 2d.
The input/output selector 2d, on the other hand, when the search condition is transferred thereto (steps 260, 261), informs the data processing unit controller 2a of a search condition (step 269), while the operation unit 3a recognizes that the search condition has been transferred to the condition buffer 3c and informs the data processing unit controller 2a of a receipt of a search condition, as shown in FIG. 47.
The data processing unit controller 2a, as shown in FIG. 45A, receives the informs from the input/output selector 2d and the operation unit 3a and informs the channel interface 2c of a search condition output (steps 227, 228, 229 in FIG. 45A and steps 211, 212 in FIG. 44A). If the data processing unit 3 is not connected to the control unit 2, the data processing unit 2a starts the input/output selector 2d in the condition transfer mode and waits for an inform from the input/output selector 2d (steps 223, 224, 230, 231 shown in FIG. 45A).
The input/output selector 2d, when the search condition is transferred thereto (steps 260, 261), informs the data processing unit controller 2a of a condition transfer (step 269). The data processing unit controller 2a, upon receiving the inform from the input/output selector 2d, informs the channel interface 2c of the search condition output (steps 211, 212 in FIG. 44A and steps 231, 229 in FIG. 45A).
(ii) Next, the channel interface 2c, when recognizing the physical address transfer command 10b (steps 208, 209 shown in FIG. 44A), starts the data processing unit controller 2a in a physical address transfer mode (step 213).
The data processing unit controller 2a starts the input/output selector 2d in the physical address transfer mode and waits for an inform from the input/output selector 2d (steps 223, 232 shown in FIG. 45A).
The input/output selector 2d, when the physical address information is transferred thereto, informs the data processing unit controller 2a of a physical address information transfer (steps 260, 262, 263, 269 shown in FIG. 47).
The data processing unit controller 2a, upon receiving the inform of physical address information transfer, starts the disk controller 2b (steps 233, 234 shown in FIG. 45A).
The disk controller 2b controls the disk 4 to position a read head (steps 252, 253 shown in FIG. 46), and then, when receiving an inform of read head positioning termination (step 254), informs the data processing unit controller 2a of a positioning termination (step 255).
The data processing unit controller 2a, upon receiving the inform from the disk controller 2b, informs the channel interface 2c of the positioning termination (steps 214, 215 in FIG. 44A and steps 235, 236 in FIG. 45A).
(iii) Next, the channel interface 2c, when recognizing the data input command 10c, starts the data processing unit controller 2a in a data input mode (steps 208, 209, 216 shown in FIG. 44A).
The data processing unit controller 2a checks the connection of the data processing unit 3, and if the data processing unit 3 is connected to the control unit 2, the data processing unit controller 2a starts the operation unit 3a, the input/output selector 2d and the disk controller 2b in the data input mode and waits for informs from the operation unit 3a, the input/output selector 2d and the disk controller 2b (steps 223, 237-240 shown in FIGS. 45A and 45B).
The disk controller 2b controls the disk 4 to request a data input (steps 252, 256 shown in FIG. 46), and examines whether or not physical address information exists in the physical address buffer 2e upon receiving the inform of data transfer termination (steps 256-1, 257). If it is detected that the next physical address information exists, the disk controller 2b performs an input operation for the next page. For thus inputting the next page, if the next physical address information is sequential to the previous physical address, the disk controller 2b waits for an inform of correct block number from the disk 4. Contrarily, if it is not sequential, the disk controller 2b controls the disk 4 to position the head and then waits for the inform of correct block number from the disk 4 (steps 252, 256, 257, 258, 253, 254). This operation enables the disk controller 2b to perform a read head positioning in a reduced time when the physical addresses are sequential.
The input/output selector 2d, when data is inputted thereto, informs the data processing unit controller 2a of a data input (steps 260, 262, 264, 269 shown in FIG. 47).
The operation unit 3a recognizes that the data has been transferred to the input buffer 3b. Next, if a search condition has been inputted to the condition buffer 3c, the operation unit 3a selects data stored in the input buffer 3b in accordance with the search condition and transfers the result to the output buffer 3d. If the condition buffer 3c is not loaded with a search condition, data stored in the input buffer 3b is transferred as it is to the output buffer 3d, and the operation unit 3a informs the data processing unit controller 2a of a search termination. Thus, even if the data processing unit 3 is connected to the control unit 2 at an arbitrary time, a page transfer request can be normally performed.
The data processing unit controller 2a, upon receiving the informs from the input/output selector 2d and the operation unit 3a, starts the input/output selector 2d in a data output mode and waits for informs of termination from the input/output selector 2d and the disk controller 2b (steps 241, 242, 243 shown in FIG. 45B).
The input/output selector 2d, when recognizing the data output, informs the data processing unit controller 2a of a data output (steps 260, 262, 264, 266, 267, 269 shown in FIG. 47).
The disk controller 2b, upon receiving the inform of correct block number from the disk 4, informs the data processing controller 2a of the positioning termination (steps 254, 255 shown in FIG. 46). Following this operation, the data processing unit controller 2a informs the channel interface 2c of the data output (steps 244-246 in FIG. 45B and steps 217, 218 in FIG. 44A).
When the data processing unit 3 is not connected to the control unit 2, the data processing unit controller 2a starts the input/output selector 2d and the disk controller 2b without input signal and waits for informs from the input/output selector 2d and the disk controller 2b (steps 223, 237, 247, 248 shown in FIGS. 45A and 45B).
The input/output selector 2d, when data is transferred thereto, informs the data processing unit controller 2a of a data output (steps 260, 262, 264, 266, 268, 269 shown in FIG. 47).
On the other hand, the disk controller 2b, when receiving an inform of correct block number from the disk 4, informs the data processing unit controller 2a of a positioning termination (steps 254, 255 shown in FIG. 46). The data processing unit controller 2a, responsive to this, informs the channel interface 2c of the data output (steps 244-246 in FIG. 45B and steps 217, 218 in FIG. 44A).
(iv) The above described processing is repeated in the same manner. The coupling with the channel is released when the disk controller 2b, upon receiving the starting signal in the data input mode, examines the physical address buffer after issuing a data input request and it is detected that the next physical address does not exist. In this event, the disk controller 2b informs the data processing unit controller 2a of a physical address termination (steps 252, 256, 256-2, 257, 259 shown in FIG. 46).
The data processing unit controller 2a, upon receiving the inform of the physical address termination from the disk controller 2b, informs the channel interface 2c of the physical address termination, followed by releasing the coupling with the channel (steps 245, 246 in FIG. 45B and steps 217, 218, 208 in FIG. 44A).
FIGS. 48, 49 and 50 are timing charts of the control unit and the respective controllers in the data processing unit in respective starting conditions. More specifically, FIG. 48 shows a case where the starting condition is a condition output, FIG. 49 a case where the starting condition is a physical address transfer, and FIG. 50 a case where the starting condition is a data input. By thus classifying the starting condition, it is possible to request the data processing unit 3 to perform processing when the data processing unit 3 is connected and only perform a page transfer when it is not connected.
Next, the processing of the operation unit 3a included in the data processing unit 3 will be described.
Data stored in the input buffer 3b has a page structure as shown in FIG. 15 such that a record 41a can be traced by a slot 41d which indicates an offset value from the head of a page 41. The slot 41d is positioned in front of a control block 41c positioned at the end of the page 41 for managing information on free spaces and the number of records in the page.
An outline of the processing performed by the operation unit will be explained with reference to FIG. 37. The slot 41d in the page 41 points the respective records 41a having contents of male (M), female (F) and so on. The operation unit 3a maintains pointers pointing records which conform to a search request, deletes other pointers and records the search termination flag 41c.
Next, the processing performed by the DBMS 6 after a data transfer has been completed will be explained.
The processing flow of the DBMS shown in FIG. 17, and the processing flow of the page determining unit shown in FIG. 37 serve as they are for explaining the third embodiment.
After transferring data, the control is given to the page determining unit 6a in the DBMS 6. The page determining unit 6a examines the assigned buffer list 14 and refers to the search termination flag 41e included in the control block 41c in a page transferred to the buffer. If the search termination flag 41e is on, which indicates that the data processing unit 3 has operated, the page determining unit 6a only starts the record editor 6f and examines the next assigned buffer list (step 105 in FIG. 17 and steps 120-125 in FIG. 40).
The outline of the processing of the record selector shown in FIG. 39 and the processing flow of the record selector shown in FIG. 41 also serve as they are for explaining the third embodiment.
The record selector 6e performs processing similar to that of the operation unit 3a which is carried out at step 123 in FIG. 40 and steps 126-130 in FIG. 41.
The outline of the processing of the record editor shown in FIG. 39 and the processing flow of the record editor shown in FIG. 42 further serve as they are for explaining the third embodiment.
The record editor 6f refers to edit condition information 11c, edits selected records in accordance with the edit condition information 11c, and accumulates the edited records in the search and edit results. In the example shown in FIG. 39, the edit condition information 11c includes C2, C4 and C6, which indicates the extraction of the second, fourth and sixth columns.
As described above, the third embodiment also enables the DBMS 6 to perform data search and edit without paying attention to whether or not the data processing unit 3 is connected to the control unit 2.
The meritorious effects produced by the above described third embodiment may be summarized as follows:
(1) The data processing unit can be connected to the control unit at an arbitrary time. In this event, if a page transfer request is received, the data processing unit is requested to perform the processing when it is connected to the control unit while a page transfer is solely performed when it is not connected. This operation allows a page transfer to be normally processed even if the data processing unit is connected to the control unit at an arbitrary time, whereby the user need not pay attention to the connection of the data processing unit.
(2) The data processing unit stores in a page the fact that the processing program has performed a requested record search and the existence of records requested by the processing program, whereby the DBMS can know whether the data processing unit has performed the record search on the page, which record in the page the record search has been performed, and so on.
(3) The page determining unit of the DBMS examines whether or not a transferred page has been edited by the data processing unit, extracts edited records from the page when it has been edited by the data processing unit and delivers the same to the processing program, thereby preventing a single page from being searched twice.
As explained above, according to the present embodiment, it is possible to connect the data processing unit to the control unit at an arbitrary time and normally perform a page transfer request even if the data processing unit is connected to the control unit at any time, which allows the user to issue a processing request without paying attention to the connection of the data processing unit.
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A data processing system capable of searching for desired data requested by a computer from a memory unit. To obviate a disadvantage that the computer has read data partially including desired data from the memory unit and selected the desired data from the read data, the data processing system is provided with a data processing unit connected to a control unit for controlling a memory unit. Desired data is selected by this data processing unit.
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CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims benefit of U.S. Provisional Patent Application Ser. No. 62/022,941, filed Jul. 10, 2014, which is herein incorporated by reference.
TECHNICAL FIELD
In various embodiments, the present invention relates to regulated voltage reference circuits, and in particular to integrated regulated voltage circuits made using only a single type of transistor.
BACKGROUND
Manufacture yield and rage of use by product users (power supply and temperature) for integrated circuits is enhanced by an ability to generate voltages that are relatively invariant with variation in power supply, temperature, and process. Evolution of improved art has included diode or zener clamps driven by a resistor, and then by current source to reduce variation in the current through the diodes. See Chapter 20 and 23 in CMOS Circuit Design, Layout and Simulation by Dr. R. Jacob Baker, 2 nd Edition, which is herein incorporated by reference herein in its entirety. While such circuits were often better than a resistor divider, the variation with temperature and even power supply were still substantial. These were further improved with the Widlar bandgap reference. See write-up about use of bipolar bandgap to create stable reference in U.S. Pat. No. 5,053,640, which is hereby incorporated by reference herein in its entirety. One conventional approach to providing a voltage reference has been to use temperature compensated zener diodes. Since the breakdown voltage of a zener diode is about 6 volts, however, this provides a lower limit on the input voltage employed in a voltage regulator circuit. Other disadvantages are also associated with zener diode voltage references, such as stability problems, process control problems and noise introduced into the circuit.
In another approach, the bandgap voltage of silicon is employed as an internal reference to provide a regulated output voltage. This approach overcomes many of the limitations of zener diode voltage references such as long-term stability errors and incompatibility with low voltage supplies. One such convention bandgap voltage reference is disclosed in R. Widlar, New Developments in IC Voltage Regulators, IEEE J. Solid-State Circuits, Vol. SC-6 (February 1971), which is hereby incorporated by reference herein in its entirety, and is illustrated generally in FIG. 1 . In this approach, a relatively stable voltage is established by adding together two scaled voltages having positive and negative temperature coefficients, respectively. The positive temperature coefficient is provided by the difference between the base-emitter voltages of two bipolar transistors Q 1 and Q 2 operating at different emitter current densities (referring to FIG. 1 ). Since these two transistors are operated at different current densities, a differential in the emitter-base voltages of the two devices is created and appears across R 3 . The negative temperature coefficient is that of the base-emitter junction of transistor Q 3 . Thus the basic bandgap cell requires three transistors, Q 1 , Q 2 and Q 3 to achieve the offsetting temperature coefficients. It can be shown that, for theoretically perfect device operation, if the sum of the initial base-emitter voltage of Q 1 and the base-emitter voltage differential of the two transistors Q 1 and Q 2 is made equal to the extrapolated energy bandgap voltage, which is +1.205V for silicon at T=0° K, then the resultant temperature coefficient equals zero. (The detailed derivation of this result may be found in the above-noted Widlar reference.)
However this approach uses bipolar devices, a process limitation for use with MOS and FET processes. Translating using beta-multiplier is shown in Dr. Baker's book, FIG. 23.13 with results at FIG. 23.13 . And trimming means are described as are familiar to those reasonably skilled in the art. Using parasitic bipolar junction transistors in the MOS process allows approximating band-gap operation with good results. Example circuits using the parasitic bipolar devices and results are shown in FIG. 23.25 and FIG. 23.26 . These approaches results in good references and are suitable for use in regulators. However, this approach requires providing the extra process step of the n-well (commonly associated with the CMOS or bi-cmos processes).
For high volume memory, especially cost sensitive commodity memory such as a Flash replacement, it is desirable to find way without these extra process steps or special transistor requirements to generate a reference. Such a preference should preferably have adequate performance to allow regulating internal nodes on the chip, such as the write voltage, by determining whether when the charge pump should be turned on and off to control the voltage generates that is above or below the power supply. And the reference can desirably be used as an input to a comparator for determining whether inputs to the chip are logic as 1s or 0s. And a regulator can be useful in the sense amp to determine memory state of signals from the memory array. Other uses may also be found by those reasonably familiar with the art for a reference and regulator generates by a lower cost process with fewer masks and process steps.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic circuit diagram.
FIG. 2 is an example plot of a simulation at 100 C. for typical process.
FIG. 3A is a circuit diagram.
FIG. 3B is a circuit diagram.
FIG. 3C is a circuit diagram.
FIG. 4 is a chart showing the simulated variation for temperature.
FIG. 5 is chart and graphs showing VREF optimization.
DETAILED DESCRIPTION
Referring to FIG. 1 schematic, the input is vdd (top right), normally forced in the range of 2.7-3.6V. The minimum voltage is determined by when the reference (VREF) is adequately within range of its desired output, for example 2.5V. The maximum voltage is determined by the maximum voltages allowed across the transistors or circuit, for example 4.3V for a 50 nm process. This voltage may be higher or lower for a different process, minimum L, minimum width, gate oxide thickness and other process variables as will be apparent to those reasonably skilled in the art. Circuit is active when enable input, EN, is logic high.
The output shown in FIG. 1 is VREF. For the configuration and sizes of transistors shown, the VREF may be relatively constant and at about 2.3V with little variation for changes in power supply and temperature, such as from 2.5-4V for the vdd input and for temperatures from −55 to 100 C. or even higher. The nominal 2.3V value for typical will change with variation in process, such as in Vt. For example at lower Vt, the VREF output will be about 2.15V, but still with little variation for changes in input power supply and temperature for Vdd >2.5V. And for higher Vt, the VREF output will be 2.5V, again with little variation for changes in power supply and temperature above about 2.7V. Examples in variation for different input, temperatures, and process (Fast, Typical, and Slow) are shown in FIG. 4 and FIG. 5 .
FIG. 2 is an example plot of a simulation at 100 C. for typical process. As the power supply, Vdd (labeled “vdd!), is varied from 0 to 5V, the output VREF rises with the increasing power supply until regulation begins and the output stays at about 2.3V as vdd! Increases. Also plotted is the bias voltage VBIAS, a self-adjusted node voltage created within the reference, which drives and biases the current sources—the transistors with gas to VBIAS and Source to drain of transistor N 10 (with gate tied to chip EN). As shown in FIG. 2 , current to operate the Reference circuit is about 90 ua for high Vdd at 100 C. When the Reference is not being used (such as when the chip is in standby), this current is eliminated by lowering the EN from high to low, which is desirable in standby to improve time between battery re-charge in a mobile device.
As can be seen in the FIG. 2 plot, the current (N 0 :d) increases smoothly as VREF comes alive and starts up towards its flat zone around 2.3V, where the current goes relatively flat also and stops increasing with increasing Vdd (above about 2.7V in this plot for the devices sizes chosen to regulate around 2.3V).
Considering FIG. 4 , the simulated variation for temperature from −20 to 100 C. for 3.6Vdd and Slow Process is 2.556−2.521=0.035V or about 1.4%. The variation for Vdd from 2.8V to 3.6V at room temp and Slow Process is 2.53−2.518=0.12V or 1%. And the variation from Slow to Fast Process at 3.6V and room temp is 2.53−2.165=0.365V or 14%. As is typical, most of the variation is for changes in process, but on a given chip for a given process, the change for temperature and voltage is far less. Accordingly, the regulator output can be adjusted by fuse or bonding adjustment to re-center the output if desired. Such adjustment in centering can be made, for example as shown in FIG. 3A , by opening or closing the connection to transistors N 18 , 21 , 22 , 25 - 30 or N 19 , 23 , 24 , 31 , 32 or by shorting or engaging resistors R 4 - 7 as will be apparent to those reasonably skilled in the art. Such re-centering can be done by simulating the process to determine best and most optimum adjustments to achieve desired centering, such as at nominal 3Vdd. As shown in FIGS. 3A-3C , such adjustments are made by metal options but the connections could be changed by fuse, anti-fuse, or bonding pads to high or low which are connected to transistors that open or short the connections shown, since the currents involved are small so higher impedance is not a significant issue.
As shown in FIG. 5 ′s bottom plot, the centering can be changed by changing device sizes. For that version of device sizes, the flat voltage is closer to 2.1V and variation is between 1.9-2.3V for different process conditions. Or in another version centered even lower, the variation is from 1.6-2.1V for the REFERENCE output VREF. For the choices made here in lower flat zone output VREF which results in it regulating at a lower Vdd, the results for process changes show a larger % variation . . . increasing to 10% in the top chart and 15% as shown in the charge below for the lower VREF output flat zone level. Further optimization at these lower VREF voltages is possible by varying not just the resistor and transistors adjusted with metal options but also other devices in the circuit, as will be apparent to one reasonably skilled in the art using incremental analysis on cause and effect.
As is shown in the first slide of FIG. 5 , optimizing the VREF can lower variation on a given process for variations in temperature . . . here from 10% to even <1% (for nominal 3.3Vdd). The variation due to Vdd can be significantly less than 5% total variation for a +/−10% variation in Vdd (from 2.8-3.6V, as is shown in the data of FIG. 4 ). The circuit continues to regulate well as Vdd is increased above 3.6V and tends to be limited by the Vmax allowed by the transistors in the circuit. Adaption of the circuit to tighter (such as 30 nm) or looser geometries (90 nm) relative to the 50 nm used for this REFERENCE will be apparent to one skilled in the art by varying all device sizes and simulating for cause and effect.
Feedback with gain is provided by the 3 gain stages rippling through true and compliment from the initial stage to the middle stage and then to the output gain stage, with current respectively from N 13 , N 12 , and N 8 . In turn the signal is developed in the 3 stages respectively across load transistors pairs: N 6 and N 7 , N 5 and N 4 , N 3 and R 0 . For the initial stage VBIAS and VRIGHT apply differential voltage across transistor gates N 9 and N 15 , with their drains driving the differential inputs to the middle stage: the gates of transistors N 10 and N 16 , with their drains in turn driving the transistor gates of the 3 rd gain stage: N 11 and N 17 . This final 3 rd stage has a load transistor N 3 with output unused but keeping the drain of differential transistor N 11 high. A resistor R 0 is used instead of a transistor to assist startup and initial gain as Vdd starts to exceed the flat zone VREF output voltage, though it is possible to also use transistor in place of R 0 . That is, the other load transistors can be replaced with resistors. And fewer or additional gain stages may be used, depending on results requires; where the additional stages can provide additional gain and less variation but at the possible negative of less stability and more tendency to oscillate depending on load (capacitance and resistance).
A basic feature of this regulator reference is current density different between the connections between VREF to VBIAS and between VREF and VRIGHT. N 2 produces one Vt drop down from VREF and similar transistor N 1 produce the other Vt drop. The source of N 1 drives VRIGHT directly and the source of N 2 drives VBIAS directly. However the loads on each of these “source followers” is different. Accordingly for VRIGHT to equal VBIAS, VREF must go to a voltage that produces the same current through each. However, the loads are different which allows VREF to find stable voltage or “operating point” as Vdd and temperature are varied. This is akin to the band-gap approach used in bipolar regulators.
Here, load on the source of N 2 is a resistance into a diode, D 1 made from an NMOS transistor wires with its gate connected to its drain which are the several larger diodes in parallel. Whereas the load on the source of N 1 is smaller diode with no resistance. Accordingly, with equal currents flowing, the voltage across the resistor, R, must offset the difference in voltage across the transistors due to the difference in size, and hence current density in each. For example, the transistors in the leg to VBIAS may be sized 50/1 u (by wiring 5 10/1 u transistors in parallel, as shown in FIG. 3A ) that are in series with the 4K resistor, R, from VBIAS. The other leg from VRIGHT has 3 transistors in parallel to ground that are sized 6/1 u+2/1 u+2/1 u to equal 10/1 u loading the N 1 source of the transistor from VREF to VRIGHT (as shown in FIG. 3B ). Thereby, at equal currents, the current density voltage difference is about 50 mV and the resistor is about 4K ohms, the current will be about 12 ua in each leg. These voltage differences and currents will vary with variations in temperature and process and Vdd.
Using a larger resistor for R 0 will result in larger gain but slower feedback, which can be adjusted for desired VREF variation and stability. Here, the loads on VREF and VBIAS and VRIGHT may be about 10 u×10 u transistors with gate to the respective node and source-drain to ground (a capacitive load on VRIGHT, omitted from FIG. 1 , would be the same as is shown for VREF in FIG. 3C ). Such load may be varied along with the actual circuit loading the VREF to obtain stable VREF that does not oscillate. Oscillation is desirably avoided or minimized since the swing may be asymmetrical so that average may shift and VREF will be different when the output is oscillating (unstable) versus stable, with the capacitor providing an averaging that allows use even if oscillating. Such loading capacitor may be made adjustable as is shown in FIG. 3C , here by metal option to open or close the connection to transistor N 33 , the load capacitance may be allowed to decrease or increase the load capacitance respectively.
The “come alive” voltage on Vdd is the Vdd voltage (VddMin) at which VREF is adequately close to its regulated value, which may be called the flat zone. This VddMin voltage is preferably lower in battery driven mobile applications where the battery can last longer if Vdd works lower. It is lowered by tying the current sources directly to Ground instead of scaling a resistor between the source of the current source transistors (gate to VBIAS) and Ground. Any drop across the source resistor will raise VddMin. Here shown is the version where the source connects to ground. As a variation, source resistor may be added to the current sources as will be apparent to those reasonably skilled in the art. Such resistors raise VddMin but improve yield since the transistors need not be so well matched.
Also, the Reference is preferably generated on a sub wire from ground so that current travels only within the REFERENCE circuit, and drops between transistors to ground are not the result of current passing along ground from one Reference circuit to another circuit on the trip. The current should preferably dead-end within the REFERENCE to improve stability and matching. Further, a separate pad and/or wire may be from Vdd to the Reference. Such separate pad can be bonded separately to the Vdd post in the package to reduce variation in Vdd to the REFERENCE. Such other techniques to improve stability and variation will be apparent to those reasonably skilled in the art.
The terms and expressions employed herein are used as terms and expressions of description and not of limitation, and there is no intention, in the use of such terms and expressions, of excluding any equivalents of the features shown and described or portions thereof. In addition, having described certain embodiments of the invention, it will be apparent to those of ordinary skill in the art that other embodiments incorporation the concepts disclosed herein may be used without departing from the spirit and scope of the invention. Accordingly, the described embodiments are to be considered in all respects as only illustrative and not restrictive.
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A method and system for generating a reference voltage are disclosed. The reference voltage is generated by generating a voltage VRIGHT using a first transistor and generating a voltage VBIAS using a second transistor. The gates of the two transistors are connected to a common node VREF, but the loads of the transistors have different resistances. At least one differential pair is used to detect a difference between voltages VRIGHT and VBIAS. VREF is forced to a value at which the source-drain currents in each of the transistors is equal. The transistors sued are NMOS transistors.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional of U.S. Ser. No. 13/190,797, filed Jul. 27, 2010, pending, and U.S. Ser. No. 13/190,797 claims the benefit of the filing date of U.S. Provisional Application Ser. No. 61/368,385, filed Jul. 28, 2010; the entire disclosures of both applications are incorporated by reference as if set forth fully herein.
FIELD OF INVENTION
[0002] The present invention relates to the use of siRNA.
BACKGROUND OF THE INVENTION
[0003] Angiogeneis is a physiological process that involves the growth of new blood vessels. An important part of this process is the production of vascular endothelial growth factor (“VEGF” or “VEGFA”), which is a chemical signal that is produced by cells and that stimulates the growth of new blood vessels.
[0004] The process is initiated when VEGFA is secreted by cells and binds to one or more cognate receptors such as the transmembrane protein kinase VEGFR1/FLT-1 and VEGFR2/FLK-1/KDR. After VEGFA binds to the transmembrane protein, a signal cascade is initiated that ultimately results in neovascularization.
[0005] Angiogeneis can be part of normal and vital body development and regulation. Unfortunately, it can also be associated with a number of undesirable conditions such as retinopathy, psoriasis, cancer, exudative age-related macular degeneration (ARMD), and rheumatoid arthritis. In these conditions, as well as in others, there are both high levels of VEGFA and concomitant increases in vascularization. Thus, the development of therapeutic strategies that focus on control of the production of VEGFA are being sought.
SUMMARY OF THE INVENTION
[0006] The present invention is directed to compositions and methods for the suppression of VEGFA expression, as well as to the treatment of conditions that are associated with the overexpression of VEGFA. Accordingly, the present invention provides kits, siRNAs and methods for introducing siRNA that suppress, in whole or in part, the production of VEGFA.
[0007] According to a first embodiment, the present invention provides a method for suppressing the expression of VEGFA. The method comprises administering in vivo (e.g., in a human) an siRNA that comprises a sequence that is a selected from the group consisting of: SEQ ID NOs: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76, 78, 80, 82, 84, 86, and 88 to an organism.
[0008] According to a second embodiment, the present invention provides a method for suppressing the expression of VEGFA. The method comprises administering in vitro an siRNA that comprises a sequence that is selected from the group consisting of: SEQ ID NOs: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76, 78, 80, 82, 84, 86, and 88.
[0009] According to a third embodiment, the present invention provides a method for suppressing expression of VEGFA. The method comprises administering an siRNA according to either of the first two embodiments, wherein the siRNA has one or more of the following modifications: 2′-O-alkyl (e.g., 2′-O-methyl) modifications of all C and U nucleotides within the sense strand as well as on the first two 5′ nucleotides of the sense strand, 2′ Fluoro modifications of all of the C and U nucleotides within the antisense strand and a 5′ phosphorylation of the nucleotide at position one of the antisense strand. In some embodiments the siRNA has 2′-O-alkyl modifications on all C and U nucleotides within the sense strand and at least one 2′-O-alkyl modification on the antisense strand. In some embodiments the siRNA has one or more overhangs of one to six nucleotides. In some embodiments all of the aforementioned modifications are present, and only those modifications are present, thus, all G and A nucleotides, other than those located at positions 1 and 2 of the sense strand have 2′-OH groups.
[0010] According to a fourth embodiment, the present invention provides a method for suppressing expression of VEGFA. The method comprises administering an siRNA according to any of the first three embodiments, wherein the siRNA has one or more of the following modifications: a cholesterol moiety attached by a C5 linker, and mismatches at one or more of positions 6, 13 and 19 of the sense strand where the sense strand is 19 nucleotides long and the antisense strand is also 19 nucleotides in length (excluding overhangs). The positions on the sense strand are measured from the 5′ end of the sense strand wherein the first 5′ nucleotide of the sense strand is identified as the 5′-most nucleotide that is base-paired with a nucleotide on the antisense strand. As such, by this definition, 5′ sense strand overhang nucleotides are not included in the counting scheme. In some of these embodiments there are no 5′ overhangs. In some of the embodiments there are one or two 3′ overhangs of 1 to 6 bases or there are no overhangs. In some embodiments, except for at positions 6, 13 and 19, within the duplex region, there is 100% complementarity.
[0011] According to a fifth embodiment, the present invention provides a pool of at least two siRNA selected from the group consisting of SEQ ID NOs: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76, 78, 80, 82, 84, 86 and 88.
[0012] According to a sixth embodiment, the present invention provides a pharmaceutical composition comprising a therapeutically effective amount of one or more of the siRNAs disclosed herein.
[0013] According to a seventh embodiment, the present invention provides a pharmaceutical composition comprising a therapeutically effective amount of an siRNA, wherein the siRNA consists of: (a) an antisense strand that is nineteen to thirty-six bases in length and that comprises a sequence selected from the group consisting of SEQ ID NOs: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76, 78, 80, 82, 84, 86, and 88; and (b) a sense strand that is nineteen to thirty-six bases in length, wherein the antisense strand and the sense strand form a duplex region of seventeen to thirty base pairs and within the duplex region there is at least 75% complementary. In the event that the duplex region of the siRNA is longer than 19 base pairs in length, additional (sense and antisense) sequences are added to the 3′ end of the antisense strand and 5′ end of the sense strand.
[0014] Through the use of the methods, siRNAs and pharmaceutical compositions described herein, one may efficiently and effectively silence VEGFA.
BRIEF DESCRIPTION OF THE FIGURES
[0015] FIGS. 1A and B demonstrate the in vivo silencing activities of two VEGFA siRNAs modified as Accell molecules and delivered by intravitreal (IVT) injection in rats.
[0016] FIG. 2 is a representation of a dose response curve for an siRNA, VEGFA 3.2 (modified as an Accell molecule).
[0017] FIGS. 3A and 3B are representations of dose response curves for another siRNA, VEGFA 3.7 (modified as an Accell molecule).
[0018] FIGS. 4A and 4B demonstrate a duration of action of up to eight weeks for an siRNA, VEGFA 3.7, modified as an Accell molecule and delivered by IVT injection in rats.
[0019] FIGS. 5A and 5B demonstrate inhibition of VEGFA expression and preretinal neovascularization in the rat oxygen-induced retinopathy (OIR) model by siRNA, VEGFA 3.7, modified as an Accell molecule.
DETAILED DESCRIPTION
Definitions
[0020] Unless stated otherwise or apparent from context, the following terms and phrases have the meanings provided below:
2′ Modification
[0021] A 2′ modification refers to a substitution of the hydroxyl group that is typically located at the 2′ position of a ribose sugar within a ribonucleotide, with another moiety, e.g., an —O-alkyl group such as —O-methyl, —O-ethyl, —O-n-propyl, —O-isopropyl etc., or another group such as a fluoro group. Where —O-alkyl modifications are present, in some embodiments the same —O-alkyl group is present on all O-alkyl-modified nucleotides. Other types of 2′ modifications are halogen groups, e.g., 2′ Fluoro, or 2′ bromo.
[0000] “Accell” siRNA
[0022] The term “Accell” refers to a preferred siRNA structure comprising the following: the sense strand is 19 nucleotides long and has: (1) 2′-O-methyl modifications on positions 1 and 2 (counting from the 5′ terminus); (2) 2′-O-methyl modifications on all Cs and Us; and (3) cholesterol conjugated to the 3′ terminus via a C5 linker. The antisense strand is 21 nucleotides in length, has a 5′ phosphate modification, contains a 2′ F modification on all Cs and Us, forms a 2 nucleotide overhang when paired with the sense strand, and contains phosphorthioate modification between (1) the two nucleotides of the overhang, and (2) between the 3′ most nucleotide of the duplexed region and the first nucleotide of the overhang. In addition, Accell molecules contain mismatches at positions 6, 13, and 19 (counting from the 5′ end of the sense strand). In all cases, these mismatches are generated by replacing the sense nucleotide with an alternative base. In this way, the antisense strand retains complete complementarity with the target molecule. For additional details, see US 2009/0209626 A1, the disclosure of which is incorporated by reference.
Complementary
[0023] The term “complementary” refers to the ability of polynucleotides to form base pairs with one another. Base pairs are typically formed by hydrogen bonds between nucleotide units in antiparallel polynucleotide strands. Complementary polynucleotide strands can base pair in the Watson-Crick manner (e.g., A to T, A to U, C to G), or in any other manner that allows for the formation of duplexes. As persons skilled in the art are aware, when using RNA as opposed to DNA, uracil rather than thymine is the base that is considered to be complementary to adenosine. However, when a U is denoted in the context of the present invention, the ability to substitute a T is implied, unless otherwise stated.
[0024] Perfect complementarity or 100% complementarity refers to the situation in which each nucleotide unit of one polynucleotide strand can hydrogen bond with a nucleotide unit of a second polynucleotide strand. Less than perfect complementarity refers to the situation in which some, but not all, nucleotide units of two strands can hydrogen bond with each other. For example, for two 20-mers, if only two base pairs on each strand can hydrogen bond with each other, the polynucleotide strands exhibit 10% complementarity. In the same example, if 18 base pairs on each strand can hydrogen bond with each other, the polynucleotide strands exhibit 90% complementarity. In some embodiments, within a duplex region, there is at least 75% complementarity, at least 80% complementarity, at least 90% complementarity, at least 95% complementarity or 100% complementarity.
Conjugate Moiety
[0025] Conjugate moieties of the disclosure (also referred to simply as “conjugates”) are moieties that are connected either directly or indirectly to a nucleotide and can target entry into a cell by a variety of means. For instance, conjugate moieties can be lipid in nature. As such, lipid based conjugate moieties can include cationic lipids, neutral lipids, sphingolipids, and fatty acids including stearic, oleic, elaidic, linoleic, linoleaidic, linolenic, and myristic acids. Alternatively, the conjugate moieties can be proteinaceous in nature including peptides that are membrane translocating (e.g., TAT, penetratin, MAP) or cationic (e.g., poly(lys), poly(arg), poly(his), poly (lys/arg/his), or protamine).
[0026] Alternatively, the conjugate moiety can be a small molecule that, for instance, targets a particular receptor or is capable of inserting itself into the membrane and being absorbed by endocytic pathways. Thus, small molecules based on adamantanes, polyaromatic hydrocarbons (e.g., napthalenes, phenanthrenes, or pyrenes), macrocyles, steroids, or other chemical scaffolds, are all potential conjugates for the disclosure.
[0027] In yet another alternative, conjugate moieties can be based on cationic polymers, such as polyethyleneimine, dendrimers, poly(alkylpyridinium) salts, or cationic albumin.
[0028] In some cases, the conjugate moieties are ligands for receptors or can associate with molecules that in turn associate with receptors. Included in this class are bile acids, small molecule drug ligands, vitamins, aptamers, carbohydrates, peptides (including but not limited to hormones, proteins, protein fragments, antibodies or antibody fragments), viral proteins (e.g., capsids), toxins (e.g., bacterial toxins), and more. Also included are conjugates that are steroidal in nature e.g., cholesterol, cholestanol, cholanic acid, stigmasterol, pregnelone, progesterones, corticosterones, aldosterones, testosterones, estradiols, ergosterols, and more. Preferred conjugate moieties of the disclosure are cholesterol (CHOL), cholestanol (CHLN), cholanic acid (CHLA), stigmasterol (STIG), and ergosterol (ERGO).
[0029] In yet another embodiment, the molecules that target a particular receptor are modified to eliminate the possible loss of conjugated siRNAs to other sources. For instance, when cholesterol-conjugated siRNAs are placed in the presence of normal serum, a significant fraction of this material will associate with the albumin and/or other proteins in the serum, thus making the siRNA unavailable for e.g., interactions with LDLs. For this reason, the conjugate moieties of the disclosure can be modified in such a way that they continue to bind or associate with their intended target (e.g., LDLs) but have lesser affinities with unintended binding partners (e.g., serum albumin).
Duplex Region
[0030] The phrase “duplex region” refers to the region in two complementary or substantially complementary polynucleotides that form base pairs with one another, either by Watson-Crick base pairing or any other manner that allows for a stabilized duplex between polynucleotide strands that are complementary or substantially complementary.
[0031] Examples of sizes of duplex regions include but are not limited to 17-30 base pairs, 17-25 base pairs, 17-23 base pairs, 18-30 base pairs, 18-25 base pairs, 18-23 base pairs, 19-30 base pairs, 19-25 base pairs and 19-23 base pairs. A duplex region may be defined by the length of base pairs, as well as the degree of complementarity over that range.
[0032] Thus, when the duplex region is formed from two separate strands of nucleotides, the antisense strand and the sense strand, it is important to note that each strand may contain nucleotides that are part of the duplex and nucleotides that are not part of the duplex at either the 5′ end or the 3′ end. An siRNA may be designed such that on the antisense strand, all nucleotides that are complementary to a target are part of the duplex region, and thus have complementary nucleotides on the sense strand. However, the siRNA may be also be designed such that the antisense strand also contains nucleotides at either its 3′ end and/or its 5′ end that although not having complementary nucleotides on the sense strand, are part of a continuous stretch of nucleotides within the antisense strand that have complementary nucleotides on the target.
[0033] By way of example, a sense strand may contain 19 nucleotides and an antisense strand may contain 21 nucleotides. All but the two 3′ most nucleotides of the antisense strand may be complementary to the 19 nucleotides on the sense strand, while the entire stretch of 21 nucleotides of the antisense strand may be complementary to a stretch of 21 nucleotides of the target. Alternatively, the two 3′ most nucleotides of the antisense strand may be selected so as not to be complementary to a portion of the target, or selected randomly or to facilitate processing such that one or both might or might not be complementary to the two nucleotides of the target that are adjacent to the nucleotides to which the other 19 nucleotides of the antisense strand are complementary.
[0034] Additionally, in different embodiments, within a duplex region there may for example be no mismatches, one mismatch, two mismatches, three mismatches, four mismatches, or five mismatches.
Mismatch
[0035] The term “mismatch” includes a situation in which Watson-Crick base pairing does not take place between a nucleotide of a sense strand and a nucleotide of an antisense strand. Examples of mismatches include but are not limited to an A across from a G, a C across from an A, a U across from a C, a U across from a G, an A across from an A, a G across from a G, a C across from C, and a U across from a U.
Linker
[0036] A linker is a moiety that attaches two or more other moieties. Though not wishing to be limited by definitions or conventions, in this application the length of the linker is described by counting the number of atoms that represents the shortest distance between the atom that joins the conjugate moiety to the linker and the oxygen atom of the terminal phosphate moiety associated with the oligonucleotide through which the linker is attached to the oligonucleotide. For example, in embodiments where the conjugate moiety is joined to the linker via a carbamate linkage, the length of the linker is described as the number of atoms that represents the shortest distance between the nitrogen atom of the carbamate linkage and the oxygen atom of the phosphate linkage. In cases where ring structures are present, counting the atoms around the ring that represent the shortest path is preferred.
[0037] Non-limiting examples of structures of the conjugate-linker that may be used in the compositions and methods of the disclosure include but are not limited to linkers/linker chemistries that are based on β-amino-1,3-diols, β-amino-1,2-diols, hydroxyprolinols, ω-amino-alkanols, diethanolamines, β-hydroxy-1,3-diols, β-hydroxy-1,2-diols, β-thio-1,3-diols, β-thio-1,2-diols, β-carboxy-1,3-diols, β-carboxy-1,2-diols, ω-hydroxy-alkanols, ω-thio-alkanols, ω-carboxy-alkanols, functionalized oligoethylene glycols, allyl amine, acrylic acid, allyl alcohol, propargyl amine, and propargyl alcohol.
[0038] In some embodiments a linker not only provides a site of attachment to the conjugate moiety, but also provides functional sites for attachment to the support and for initiation of oligonucleotide synthesis. Preferably, these sites are hydroxyl groups; most preferably, they are a primary hydroxyl group and a secondary hydroxyl group, to allow them to be chemically distinguished during synthesis of the conjugate-modified solid support. One hydroxyl group, preferably the primary hydroxyl group, is protected with a protecting group that can be removed as the first step in the synthesis of the oligonucleotide, according to methods well understood by those of ordinary skill in the art. Preferably, this protecting group is chromophoric and can be used to estimate the amount of the conjugate moiety attached to the solid support; most preferably, the group is chosen from triphenylmethyl (Tr), monomethoxytriphenylmethyl (MMTr), dimethoxytriphenylmethyl (DMTr) and trimethoxytriphenylmethyl (TMTr). Another hydroxyl group, preferably a secondary hydroxyl group, is derivatized with a functionalized tether that can covalently react with a functional group on the solid synthesis support, according to methods well understood by those of ordinary skill in the art. Preferable tethers are, by way of example, dicarboxylic acids such as succinic, glutaric, terephthalic, oxalic, diglycolic, and hydroquinone-0,0′-diacetic. One of the carboxylic acid functionalities of the tether is reacted with the hydroxyl to provide an ester linkage that is cleavable using basic reagents (hydroxide, carbonate or amines), while the other carboxylic acid functionality is reacted with the synthesis support, usually through formation of an amide bond with an amine functionality on the support. The linker may also confer other desirable properties on the oligonucleotide conjugate: improved aqueous solubility, optimal distance of separation between the conjugate moiety and the oligonucleotide, flexibility (or lack thereof), specific orientation, branching, and others.
[0039] Preferably, the chemical bond between the linker and the conjugate moiety is a carbamate linkage; however, alternative chemistries are also within the scope of the disclosure. Examples of functional groups on linkers that form a chemical bond with a conjugate moiety include, but are not limited to, hydroxyl, amine, carboxylic acid, carboxylic acid halide, carboxylic acid active ester, carbonyl, chlorocarbonyl, imidazolylcarbonyl, thiol, maleimide, haloalkyl, sulfonyl, allyl and propargyl. Examples of chemical bonds that are formed between a linker and a conjugate include, but are not limited to, those based on carbamates, ethers, esters, amides, disulfides, thioethers, phosphodiesters, phosphorothioates, phorphorodithioate, sulfonamides, sulfonates, sulfones, sulfoxides, ureas, hydrazide, oxime, photolabile linkages, C—C bond forming groups such as Diels-Alder cyclo-addition pairs or ring-closing metathesis pairs, and Michael reaction pairs. In general, the conjugate moiety will have an appropriate functional group either naturally or chemically installed; the linker will then be synthesized with a functional group chosen to efficiently and stably react with the functional group on the conjugate moiety.
[0040] Linkers that have the same length, but are capable of associating with two or more conjugates, are also specifically contemplated.
[0041] In another embodiment, the linker may be a nucleoside derivative. The nucleoside may be, for example, a ribonucleoside, 2′-deoxyribonucleoside, or 2′-modified-2′-deoxyribonucleoside, such as 2′-O-methyl or 2′-fluoro. The nucleoside may be, for example, an arabinonucleoside or a 2′-modified arabinonucleoside. Using methods well known to those of ordinary skill in the art, purine and pyrimidine nucleosides may be modified at particular sites on the base to provide linkers and functional groups for attachment of conjugate moieties. For example, pyrimidine nucleosides, such as uridine and cytidine, may be modified at the 5-position of the uracil or cytosine base using mercuric acetate, a palladium catalyst, and an allylic reagent such as allylamine, allyl alcohol, or acrylic acid. Alternatively, 5-iodopyrimidines may be modified at the 5-position with a palladium catalyst and a propargylic reagent such as propargyl amine, propargyl alcohol or propargylic acid. Alternatively, uridine may be modified at the 4-position through activation with triazole or a sulfonyl chloride and subsequent reaction with a diamine, amino alcohol or amino acid. Cytidine may be similarly modified at the 4-position by treatment with bisulfite and subsequent reaction with a diamine, amino alcohol or amino acid. Purines may be likewise modified at the 7, 8 or 9 positions using similar types of reaction sequences.
[0042] In preferred embodiments, the linker is from about 3 to about 9 atoms in length. Thus, the linker may be 3, 4, 5, 6, 7, 8, or 9 atoms in length. Preferably, the linker is 5, 6, 7 or 8 atoms in length. More preferably, the linker is 5 or 8 atoms in length. Most preferably the linker is a straight chain C5 linker i.e., there are 5 carbon atoms between the atom that joins the conjugate moiety to the linker and the oxygen atom of the terminal phosphate moiety associated with the oligonucleotide through which the linker is attached to the oligonucleotide. Thus, where the conjugate moiety is joined to a C5 linker via a carbamate linkage, there are 5 carbon atoms between the nitrogen atom of the carbamate linkage and the oxygen atom of the phosphate linkage.
[0043] In one preferred embodiment, the conjugate moiety is cholesterol and the linker is a C5 linker (a 5 carbon linker) attached to the cholesterol via a carbamate group, thus forming a Chol-C5 conjugate-linker. When attached via a phosphodiester linkage to the 5′ and/or 3′ terminus of a sense and/or antisense oligonucleotide of a duplex, the resulting conjugate-linker-oligonucleotide can have the structure:
[0000]
[0044] In another preferred embodiment, the conjugate moiety is cholesterol and the linker is a C3 linker attached to the cholesterol via a carbamate group, thus forming a Chol-C3 conjugate-linker. When attached via a phosphodiester linkage to the 5′ and/or 3′ terminus of a sense and/or antisense oligonucleotide, the resulting conjugate linker-oligonucleotide can have the structure:
[0000]
[0045] In another preferred embodiment, the conjugate moiety is cholesterol and the linker is a C8 linker (a 8 carbon linker) attached to the cholesterol via a carbamate group, thus forming a Chol-C8 conjugate-linker. When attached via a phosphodiester linkage to the 5′ and/or 3′ terminus of a sense and/or antisense oligonucleotide, the resulting conjugate-linker oligonucleotide can have the structure:
[0000]
[0046] In another preferred embodiment, the conjugate moiety is cholesterol and the linker is a PRO linker (a 4 carbon linker) attached to the cholesterol via a carbamate group, thus forming a Chol-PRO conjugate-linker.
[0047] In another preferred embodiment, the conjugate moiety is cholesterol and the linker is a PIP linker (a 6 carbon linker) attached to the cholesterol via a carbamate group, thus forming a Chol-PIP conjugate-linker. When attached via a phosphodiester linkage to the 5′ and/or 3′ terminus of a sense and/or antisense oligonucleotide, the resulting conjugate-linker-oligonucleotide can have the structure:
[0048] In another preferred embodiment, the conjugate moiety is cholesterol and the linker is a C6-HP (also referred to as “HP6”) linker (a 9 carbon linker) attached to the cholesterol via a carbamate group, thus forming a Chol-C6-HP conjugate-linker. When attached via a phosphodiester linkage to the 5′ and/or 3′ terminus of a sense and/or antisense oligonucleotide, the resulting conjugatelinker-oligonucleotide can have the structure:
[0000]
Nucleotide
[0049] Unless otherwise specified, the term “nucleotide” refers to a ribonucleotide or a deoxyribonucleotide or modified form thereof, as well as an analog thereof. Nucleotides include species that comprise purines, e.g., adenine, hypoxanthine, guanine, and their derivatives and analogs, as well as pyrimidines, e.g., cytosine, uracil, thymine, and their derivatives and analogs. In some embodiments, all nucleotides are selected from the group of modified or unmodified A, C, G or U.
[0050] Nucleotide analogs include nucleotides having modifications in the chemical structure of the base, sugar and/or phosphate, including, but not limited to, 5-position pyrimidine modifications, 8-position purine modifications, modifications at cytosine exocyclic amines, and substitution of 5-bromo-uracil; and 2′-position sugar modifications, including but not limited to, sugar-modified ribonucleotides in which the 2′-OH is replaced by a group such as an H, OR, R, halo, SH, SR, NH 2 , NHR, NR 2 , or CN, wherein R is an alkyl moiety. Nucleotide analogs are also meant to include nucleotides with bases such as inosine, queuosine, xanthine, sugars such as 2′-methyl ribose, non-natural phosphodiester linkages such as methylphosphonates, phosphorothioates and peptides.
[0051] Modified bases refer to nucleotide bases such as, for example, adenine, guanine, cytosine, thymine, uracil, xanthine, inosine, and queuosine that have been modified by the replacement or addition of one or more atoms or groups. Some examples of types of modifications that can comprise nucleotides that are modified with respect to the base moieties include but are not limited to, alkylated, halogenated, thiolated, aminated, amidated, or acetylated bases, individually or in combination. More specific examples include, for example, 5-propynyluridine, 5-propynylcytidine, 6-methyladenine, 6-methylguanine, N,N,-dimethyladenine, 2-propyladenine, 2-propylguanine, 2-aminoadenine, 1-methylinosine, 3-methyluridine, 5-methylcytidine, 5-methyluridine and other nucleotides having a modification at the 5 position, 5-(2-amino)propyl uridine, 5-halocytidine, 5-halouridine, 4-acetylcytidine, 1-methyladenosine, 2-methyladenosine, 3-methylcytidine, 6-methyluridine, 2-methylguanosine, 7-methylguanosine, 2,2-dimethylguanosine, 5-methylaminoethyluridine, 5-methyloxyuridine, deazanucleotides such as 7-deaza-adenosine, 6-azouridine, 6-azocytidine, 6-azothymidine, 5-methyl-2-thiouridine, other thio bases such as 2-thiouridine and 4-thiouridine and 2-thiocytidine, dihydrouridine, pseudouridine, queuosine, archaeosine, naphthyl and substituted naphthyl groups, any O- and N-alkylated purines and pyrimidines such as N6-methyladenosine, 5-methylcarbonylmethyluridine, uridine 5-oxyacetic acid, pyridine-4-one, pyridine-2-one, phenyl and modified phenyl groups such as aminophenol or 2,4,6-trimethoxy benzene, modified cytosines that act as G-clamp nucleotides, 8-substituted adenines and guanines, 5-substituted uracils and thymines, azapyrimidines, carboxyhydroxyalkyl nucleotides, carboxyalkylaminoalkyl nucleotides, and alkylcarbonylalkylated nucleotides. Modified nucleotides also include those nucleotides that are modified with respect to the sugar moiety, as well as nucleotides having sugars or analogs thereof that are not ribosyl. For example, the sugar moieties may be, or be based on, mannoses, arabinoses, glucopyranoses, galactopyranoses, 4′-thioribose, and other sugars, heterocycles, or carbocycles.
[0052] The term nucleotide is also meant to include what are known in the art as universal bases. By way of example, universal bases include but are not limited to 3-nitropyrrole, 5-nitroindole, or nebularine. The term “nucleotide” is also meant to include the N3′ to P5′ phosphoramidate, resulting from the substitution of a ribosyl 3′ oxygen with an amine group.
[0053] Further, the term nucleotide also includes those species that have a detectable label, such as for example a radioactive or fluorescent moiety, or mass label attached to the nucleotide.
Pharmaceutically Acceptable Carrier
[0054] The phrase “pharmaceutically acceptable carrier” means a pharmaceutically acceptable salt, solvent, suspending agent or vehicle for delivering a composition of the present disclosure to an organism such as an animal or human. The carrier may be liquid, semisolid or solid, and is often synonymously used with diluents, excipient, or salt. The phrase “pharmaceutically acceptable” means that any ingredient, excipient, carrier, diluent or component disclosed is one that is suitable for use with humans and/or animals without undue adverse side effects (such as toxicity, isolation and allergic response) commensurate with a reasonable benefit/risk ratio. See Remington's Pharmaceutical Science le edition, Osol, A. Ed. (1980).
Ribonucleotide and Ribonucleic Acid
[0055] The term “ribonucleotide” and the phrase “ribonucleic acid” (RNA), refer to a modified or unmodified nucleotide or polynucleotide comprising at least one ribonucleotide unit. A ribonucleotide unit comprises an hydroxyl group attached to the 2′ position of a ribosyl moiety that has a nitrogenous base attached in N-glycosidic linkage at the 1′ position of a ribosyl moiety, and a moiety that either allows for linkage to another nucleotide or precludes linkage.
Sense Strand/Antisense Strand
[0056] The phrase “sense strand” refers to a polynucleotide that comprises a sequence that is in whole or in part, the same as a target nucleic acid sequence such as messenger RNA or a sequence of DNA. The phrase “antisense strand” refers to a polynucleotide that comprises a sequence that is in whole or in part, the complement of a target nucleic acid sequence such as messenger RNA or a sequence of DNA.
[0057] When a sequence of an siRNA is provided, by convention, unless otherwise indicated it is of the sense strand, and the complementary antisense strand is implicit. In a duplex siRNA (formed from two separate strands) one strand may be the sense strand, and the other strand may be the antisense strand. If overhangs are present, the phrase “sense region” may refer to the nucleotide sequence portion of the sense strand other than overhang regions. Similarly, the phrase “antisense region” may refer to the nucleotide sequence portion of the antisense strand other than overhang regions. If the siRNA is a shRNA, there are not two separate strands, and the “sense region” is the portion of the duplex region that has a sequence that is in whole or in part the same as the target sequence, and the “antisense region” is the sequence of nucleotides that is in whole or in part complementary to the target sequence and to the sense region.
[0058] Examples of lengths of sense strands and antisense strands are 19-36 bases, 19-30 bases, 19-25 bases and 19-23 bases. These strand lengths include possible overhang regions.
[0000] siRNA
[0059] The term “siRNA” refers to small inhibitory RNA duplexes that induce the RNA interference (RNAi) pathway. As used herein, these molecules can vary in length (generally 17-30 base pairs plus overhangs) and contain varying degrees of complementarity to their target mRNA in the antisense strand. Some, but not all, siRNA have unpaired overhanging bases on the 5′ or 3′ end of the sense strand and/or the antisense strand. The term “siRNA” includes duplexes of two separate strands, and unless otherwise specified as well as single strands that can form hairpin structures comprising a duplex region, which is referred to as a shRNA.
[0000] siStable
[0060] The term “siStable” refers to a chemical modification pattern that is associated with a particular duplex. Specifically, siStable siRNA comprise the following structures: the sense strand is 19 nucleotides long and has (1) 2′-O-methyl modifications on positions 1 and 2 (counting from the 5′ terminus), and (2) 2′-O-methyl modifications on all Cs and Us. The antisense strand is 21 nucleotides in length, has a 5′ phosphate modification, contains a 2′ F modification on all Cs and Us, forms a 2 nucleotide overhang when paired with the sense strand, and contains phosphorthioate modifications between (1) the two nucleotides of the overhang, and (2) between the 3′ most nucleotide of the duplexed region and the first nucleotide of the overhang. For details, see US 2007/0269889 A1.
Target
[0061] The term “target” is used in a variety of different forms throughout this document and is defined by the context in which it is used. “Target mRNA” refers to a messenger RNA to which a given siRNA can be directed against. “Target sequence” and “target site” refer to a sequence within the mRNA to which the sense strand of an siRNA shows varying degrees of identity and the antisense strand exhibits varying degrees of complementarity. The phrase “siRNA target” can refer to the gene, mRNA, or protein against which an siRNA is directed. Similarly, “target silencing” can refer to the state of a gene, or the corresponding mRNA or protein.
Therapeutically Effective Amount
[0062] A “therapeutically effective amount” of a composition containing a sequence that encodes a VEGFA-specific siRNA (i.e., an effective dosage), is an amount that inhibits expression of the polypeptide encoded by the VEGFA target gene by at least 10 percent. Higher percentages of inhibition, e.g., at least 15, at least 20, at least 30, at least 40, at least 50, at least 75, at least 85, at least 90 percent or higher may be preferred in certain embodiments. The skilled artisan will appreciate that certain factors may influence the dosage and timing required to effectively treat a subject, including but not limited to the severity of the disease or disorder, previous treatments, the general health and/or age of the subject, and other diseases present. Moreover, treatment of a subject with a therapeutically effective amount of a composition can include a single treatment or a series of treatments. In some cases transient expression of the siRNA may be desired. When an inducible promoter is included in the construct encoding an siRNA, expression is assayed upon delivery to the subject of an appropriate dose of the substance used to induce expression.
[0063] Appropriate doses of a composition depend upon the potency of the molecule (the sequence encoding the siRNA) with respect to the expression or activity to be modulated. One or more of these molecules can be administered to an animal (e.g., a mammal such as a human or other primate, e.g., a chimpanzee, orangutan, ape, monkey etc., or dog, cat, horse, cow, rat, sheep, or mouse) to modulate expression or activity of one or more target polypeptides. A physician may, for example, prescribe a relatively low dose at first, subsequently increasing the dose until an appropriate response is obtained. In addition, it is understood that the specific dose level for any particular subject will depend upon a variety of factors including the activity of the specific compound employed, the age, body weight, general health, gender, and diet of the subject, the time of administration, the route of administration, the rate of excretion, any drug combination, and the degree of expression or activity to be modulated.
[0064] A therapeutically effective amount of a VEGFA-specific siRNA is useful for treating a condition, disease, or disorder associated with elevated expression of VEGFA, including, but not limited to, psoriasis, cancer, rheumatoid arthritis, ocular neovascularization, abnormal angiogenesis, retinal vascular permeability, retinal edema, diabetic retinopathy (particularly proliferative diabetic retinopathy), diabetic macular edema, exudative age-related macular degeneration, sequela associated with retinal ischemia, and posterior segment neovascularization.
Preferred Embodiments
[0065] The present invention will now be described in connection with preferred embodiments. These embodiments are presented in order to aid in an understanding of the present invention and are not intended, and should not be construed, to limit the invention in any way. All alternatives, modifications and equivalents that may become apparent to those of ordinary skill upon reading this disclosure are included within the spirit and scope of the present invention.
[0066] Furthermore, this disclosure is not a primer on compositions or methods for performing RNA interference. Basic concepts known to persons skilled in the art have not been set forth in detail.
[0067] According to a first embodiment, the present invention provides a method for decreasing expression of VEGFA, in vivo, comprising administering an siRNA to an organism, wherein the siRNA comprises a sequence selected from SEQ ID NO: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76, 78, 80, 82, 84, 86, and 88.
[0068] The subject may be any organism that possesses an RNAi pathway, including, but not limited to a mammal, bird or reptile. Examples of mammals include, but are not limited to humans, monkeys, apes, chimpanzees, dogs, cats, mice and rats.
[0069] In addition, the duplex formed by the sense strand and the antisense strand can comprise at least one overhang, each overhang comprising at least one nucleotide. The overhang(s) can for example be located:
[0070] at the 5′ end of the sense strand;
[0071] at the 3′ end of the sense strand;
[0072] at the 5′ and 3′ end of the sense strand;
[0073] at the 5′ end of the antisense strand;
[0074] at the 3′ end of the antisense strand;
[0075] at the 5′ and 3′ end of the antisense strand;
[0076] at the 5′ end of the sense strand and the 5′ end of the antisense strand; or
[0077] at the 3′ end of the sense strand and the 3′ end of the antisense strand.
[0078] In some embodiments, the overhang is six or fewer nucleotides in length, in preferred embodiments, an overhang is present at the 3′ end of the antisense strand, i.e., attached to the 3′ most nucleotides of the antisense regions. More preferably, the overhang on the 3′ end of the antisense strand is two nucleotides in length. The selection of the bases for nucleotides in the overhang may be made in an arbitrary manner i.e., the overhang nucleotides may or may not base pair with a target mRNA. For convenience and simplicity, a two nucleotide overhang is usually a UU overhang (although AA, GG, CC, AC, CA, AG, GA, GC, and CG di-nucleotide overhangs, and others, are also contemplated, see Vermeulen et al. (2005) RNA 11 (5): 674-682). Preferably, the linkage between the nucleotides of the overhang as well as the linkage between the terminal nucleotide of the duplex and the first nucleotide of the overhang are phosphorothioate linkages. In one particularly preferred embodiment, the antisense strand comprises a UU overhang located at the 3′ end of the antisense strand with a phosphorothioate linkage linking the 3′ terminal U to the second U nucleotide, and with a phosphorothioate linkage linking the second U nucleotide to the next nucleotide (in the 5′ direction) in the antisense strand.
[0079] In some embodiments, the 5′ end of the sense strand and/or the 3′ end of the sense strand and/or the 5′ end of the antisense strand and/or the 3′ end of the antisense strand comprises a terminal phosphate. Preferably, a terminal phosphate is located at the 5′ end of the antisense strand.
[0080] In some embodiments there are no modified nucleotides (i.e., the 2′ position of each of the ribose sugars has an OH moiety). In other embodiments there are one or more than one chemical modifications. For example, there may be one or more or all of:
(1) 2′-O-alkyl modifications of positions 1 and 2 and all C nucleotides, and all U nucleotides of the sense strand (e.g., O-methyl, O-ethyl, O-n-propyl, O-isopropyl, etc.); (2) a conjugate moiety wherein the conjugate moiety is comprised of, consists essentially of or consists of a linker and a conjugate moiety such as a cholesterol moiety and the linker is attached to the 3′ position of the last nucleotide of the sense strand; (3) 2′ Fluoro modifications of all C and U nucleotides of the antisense strand or at least one 2′-O-alkyl modification on the antisense strand; (4) phosphorylation at the 5′ position of the first nucleotide of the antisense strand and all other nucleotides may in some embodiments be unmodified; (5) one or more overhangs; and (6) one or more phosphorothioate modifications associated with the nucleotides of any overhang on either strand.
[0087] In some embodiments, where overhangs are present, 2′-O modifications may appear in the Cs and Us of the overhangs on the sense strand and 2′-fluoro modifications may appear in the Cs and Us of on the antisense strand. In other embodiments the 2′-O modifications and 2′-fluoro only appear within nucleotides in the duplex region. Additionally, in some embodiments it may be desirable to have all of the aforementioned 2′ Cs and Us modified in each strand (either including or excluding in any overhang regions if present). However, in other embodiments it may be desirable to have fewer than all of the C and Us on each or either strand contain the aforementioned modifications. When fewer than all Cs and Us are modified, the total number of C and U modifications may be chosen by for example, an absolute number, for example 1-8 or 2-7 or 3-6 are modified or it may for example be defined in terms of the number that are not modified, e.g., all but 1, all but 2, all but 3, all but 4, all but 5, all but 6, all but 7, all but 8 of the Cs or Us are unmodified. In other embodiments, it may be preferable to omit a 2′ modification at one or more specific positions, e.g., at one or more of positions 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, and if present, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29 or 30. As a person of ordinary skill in the art will recognize preferably each strand contains at least one C or U nucleotide. Additionally, in some embodiments on the antisense strand it may be preferable to have 2′ fluoro groups on 0-30 or 0-25 or 0-23 or 0-19 or 1-30 or 1-25 or 1-23 or 1-19 or 3-30 or 3-25 or 3-23 or 3-19 or 5-30 or 5-25 or 5-23 or 5-19 or 7-30 or 7-25 or 7-23 or 7-19 or 10-30 or 10-25 or 10-23 or 10-19 or 8-15 or 10-12 nucleotides. The modified nucleotides may all be pyrimidines, all be purines or be a combination of purines and pyrimidines. In some embodiments all nucleotides on the antisense strand have 2′ fluoro groups and this strand may have at least one pyrimidine, at least one purine, all pyrimidines, all purines or a combination of purines and pyrimidines. Further in some embodiments the 2′ fluoro groups are on any overhang nucleotides if present while in other embodiments, the overhang nucleotides do not include these modifications. Similarly, in some embodiments on the sense strand it may be preferable to have 2′-O-alkyl (e.g., 2′-O-methyl) groups on 0-30 or 0-25 or 0-23 or 0-19 or 1-30 or 1-25 or 1-23 or 1-19 or 3-30 or 3-25 or 3-23 or 3-19 or 5-30 or 5-25 or 5-23 or 5-19 or 7-30 or 7-25 or 7-23 or 7-19 or 10-30 or 10-25 or 10-23 or 10-19 or 8-15 or 10-12 nucleotides. The modified nucleotides may all be pyrimidines, all be purines or be a combination of purines and pyrimidines. In some embodiments all nucleotides on the sense strand have 2′-O-alkyl groups and this strand may have at least one pyrimidine, at least one purine, all pyrimidines, all purines or a combination of purines and pyrimidines. Further in some embodiments the 2′-O-alkyl groups are on any overhang nucleotides if present while in other embodiments, the overhang nucleotides do not include these modifications.
[0088] In embodiments that have at least one 2′-O-alkyl modification on the antisense strand, there may for example be, from one to ten, one to eight, one to six, one to five, one to four, one to three, or one to two modifications. In other embodiments, there may be exactly one, two, three, four, five, six, seven, eight, nine or ten such modifications. These at least one modifications may for example be located in a 3′ antisense overhang region and/or at one or more of positions one to eight, one to seven, one to six, one to five, one to four, one to three, or one to two of the antisense strand as measured from the 5′ end of that strand and within the duplex region.
[0089] By way of non-limiting examples, there may be a single 2′-O-alkyl modification (e.g., methyl) at any of positions 1, 2, 3, 4, 5, 6, 7 or 8 of the antisense strand. Alternatively, there may be a single 2′-O-alkyl modification in one of the two nucleotides in a UU overhang or in both of those nucleotides. Other combinations of 2′-O-alkyl modifications include but are not limited to at positions 1 and 2, 1 and 3, 1 and 4, 1 and 5, 1 and 6, 1 and 7, 1 and 8, 2 and 3, 2 and 4, 2 and 5, 2 and 6, 2 and 7, 2 and 8, 3 and 4, 3 and 5, 3 and 6, 3 and 7, 3 and 8, 4 and 5, 4 and 6, 4 and 7, 4 and 8, 5 and 6, 5 and 7, 5 and 8, 6 and 7, 6 and 8, 7 and 8, 1 and one of the two nucleotides in a UU overhang or in both of those nucleotides, 2 and one of the two nucleotides in a UU overhang or in both of those nucleotides, 3 and one of the two nucleotides in a UU overhang or in both of those nucleotides, 4 and one of the two nucleotides in a UU overhang or in both of those nucleotides, 5 and one of the two nucleotides in a UU overhang or in both of those nucleotides, 6 and one of the two nucleotides in a UU overhang or in both of those nucleotides, 7 and one of the two nucleotides in a UU overhang or in both of those nucleotides, or 8 and one of the two nucleotides in a UU overhang or in both of those nucleotides.
[0090] Furthermore, in some embodiments in which there is at least one 2′-O-alkyl modification present on the antisense strand the position is selected such that only A or G bases contain the modification, thereby allowing for all C and U bases to be modified with fluoro groups. In other embodiments, one or more C or U bases contain the 2′-O-alkyl modification. In those cases, the siRNA may be designed such that any C and U base that does not have a 2′-O-alkyl modification has a 2′ fluoro modification.
[0091] In some embodiments, the siRNA contains a duplex region that is 17-30 base pairs long or 18-30 base pairs long or 19-30 base pairs long or 19-23 base pairs long or 19-21 base pairs long or 18-23 base pairs long. When a duplex region is 17 base pairs long and a 19-mer antisense sequence is provided, it may be that two bases at the 3′ end of the antisense 19-mer form an overhang.
[0092] Within the duplex region there may be 100% complementarity or less than 100% complementarity, e.g., at least 80% complementarity, at least 85% complementarity, at least 90% complementarity, or at least 95% complementarity. In one embodiment, there is 100% complementarity except at sense strand position 6 or at position 13, or at position 19, or at positions 6 and 13 or at positions 13 and 19 or positions 6 and 19, or at positions 6, 13 and 19. In this example, at the designated position(s) there is a mismatch. Mismatches are introduced into the duplex by altering the identity of a nucleotide in the sense strand. In this way, the antisense strand retains 100% complementarity with the region of the target mRNA. Furthermore, as used herein, a position number within a strand refers to the location of that nucleotide relative to the first, i.e., 5′ most, nucleotide of the duplex region. Thus, position 1 of the sense strand is the 5′ most position of the sense strand, while position 1 of the antisense strand is the 5′ most position of the antisense strand. Position 2 is the position immediately downstream (or 3′) of position 1 of the respective strand.
[0093] As stated above, in some embodiments, a mismatch is introduced into the sense strand. In some cases, the nucleotides introduced at the positions of mismatch have the same identity or chemical nature as the nucleotide in the antisense strand that normally binds to that particular sense strand nucleotide. Thus, for example, if one has a double stranded molecule containing 19 nucleotides in the sense strand and 19 nucleotides in the antisense strand with no overhangs on either strand, if a mismatch is introduced at position 6 of the sense strand (counting from the 5′ end of the strand), the nucleotide at that position of the sense strand does not pair in a Watson-Crick fashion with the nucleotide at position 14 of the antisense strand. Furthermore, if the nucleotide at position 14 of the antisense strand is e.g., a “C”, then the mismatch would be achieved by introducing a “C” at position 6 of the sense strand. As a result of these changes, the nucleotide at position 6 of the sense strand no longer has identity with the corresponding nucleotide in the target region of e.g., the mRNA. However, the antisense nucleotide at e.g., position 14 would retain complementarity to the nucleotide on the target region.
[0094] The position of the conjugate-linker on the duplex oligonucleotide complex can vary with respect to the strand or strands that are conjugated (e.g., the sense strand, the antisense strand, or both the sense and antisense strands), the position or positions within the strand that are modified (i.e., the nucleotide positions within the strand or strands), and the position on the nucleotide(s) that are modified (e.g., the sugar, the base). Conjugate-linkers can be placed on the 5′ and/or 3′ terminus of one or more of the strands. For example, a conjugate-linker can be placed on the 5′ end of the sense strand and/or the 3′ end of the sense strand and/or the 3′ end of the antisense strand. A conjugate-linker can be attached at the 5′ and/or 3′ end of a strand via a phosphodiester bond. In preferred embodiments, a conjugate-linker is attached to the one or both ends of the sense strand via a phosphodiester bond, more preferably to the 3′ end of the sense strand.
[0095] A conjugate-linker can also be attached to internal positions of the sense strand and/or antisense strand. In addition, multiple positions on the nucleotides including the 5-position of uridine, 5-position of cytidine, 4-position of cytidine, 7-position of guanosine, 7-position of adenosine, 8-position of guanosine, 8-position of adenosine, 6-position of adenosine, 2′-position of ribose, 5′-position of ribose, and 3′-position of ribose, can be employed for attachment of the conjugate to the nucleic acid.
[0096] In another embodiment, the present invention provides a method of gene silencing, comprising introducing into a cell in vitro at least one siRNA that comprises a sequence that is selected from SEQ ID NOs: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76, 78, 80, 82, 84, 86, and 88. The siRNA can be introduced by allowing passive uptake of siRNA, or through the use of a vector.
[0097] Any of the methods and kits disclosed herein can employ either unimolecular siRNAs, siRNAs comprised of two separate polynucleotide strands, or combinations thereof. Furthermore, any of the methods disclosed herein can be used in gene silencing using a variety of different protocols. In one non-limiting example, two or more siRNAs targeting the same gene can be administered simultaneously. As is the case with individual siRNAs, the two or more siRNA can be administered in a single dose or single transfection, in multiple doses, or as the case may be.
[0098] In one embodiment the invention provides the use of a compound that inhibits the expression and/or activity of a VEGFA gene for the manufacture of a medicament for treatment of a disorder associated with over-expression of VEGFA. The medicaments may, for example, be administered orally, parenterally (including subcutaneously, intramuscularly, or intravenously), rectally, transdermally, buccally, or nasally. The medicaments may comprise any one or more of the compounds described herein.
[0099] Interfering RNA may be delivered directly to the eye by ocular tissue injection such as periocular, conjunctival, subtenon, intracameral, intravitreal, intraocular, subretinal, subconjunctival, retrobulbar, or intracanalicular injections; by direct application to the eye using a catheter or other placement device such as a retinal pellet, intraocular insert, suppository or an implant comprising a porous, non-porous, or gelatinous material; by topical ocular drops or ointments; or by a slow release device in the cul-de-sac or implanted adjacent to the sclera (transscleral) or in the sclera (intrascleral) or within the eye. Intracameral injection may be through the cornea into the anterior chamber to allow the agent to reach the trabecular meshwork. Intracanalicular injection may be into the venous collector channels draining Schlemm's canal or into Schlemm's canal.
[0100] For ophthalmic delivery, an interfering RNA may be combined with ophthalmologically acceptable preservatives, co-solvents, surfactants, viscosity enhancers, penetration enhancers, buffers, sodium chloride, or water to form an aqueous, sterile ophthalmic suspension or solution. Solution formulations may be prepared by dissolving the interfering RNA in a physiologically acceptable isotonic aqueous buffer. Further, the solution may include an acceptable surfactant to assist in dissolving the interfering RNA. Viscosity building agents, such as hydroxymethyl cellulose, hydroxyethyl cellulose, methylcellulose, polyvinylpyrrolidone, or the like may be added to the compositions of the present invention to improve the retention of the compound.
[0101] In order to prepare a sterile ophthalmic ointment formulation, the interfering RNA is combined with a preservative in an appropriate vehicle, such as mineral oil, liquid lanolin, or white petrolatum. Sterile ophthalmic gel formulations may be prepared by suspending the interfering RNA in a hydrophilic base prepared from the combination of, for example, CARBOPOL®-940 (BF Goodrich, Charlotte, N.C.), or the like, according to methods known in the art. VISCOAT® (Alcon Laboratories, Inc., Fort Worth, Tex.) may be used for intraocular injection, for example. Other compositions of the present invention may contain penetration enhancing agents such as cremephor and TWEEN® 80 (polyoxyethylene sorbitan monolaureate, Sigma Aldrich, St. Louis, Mo.), in the event the interfering RNA is less penetrating in the eye.
[0102] The present invention also provides pharmaceutical compositions that comprise an siRNA of the present invention in a pharmaceutically acceptable carrier. Thus, in another embodiment, the present invention is directed to a pharmaceutical composition comprising a therapeutically effective amount of an siRNA, wherein the siRNA consists of: (a) a sense strand and an antisense strand that form a duplex region, wherein the duplex region is 17-30 base pairs in length and comprises an antisense region that has a sequence selected from the group consisting of SEQ ID NOs: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76, 78, 80, 82, 84, 86 and 88; and (b) a sense region that is 100% complementary to the antisense region or has mismatches at one or more positions. In one example, the molecule consists of a sense strand and an antisense strand that form a 19 base double stranded complex and mismatches that are located at positions 6, 13 or 19 of the sense region, wherein said positions are defined relative to the 5′ most nucleotide of the sense strand that is part of the duplex region. For all of the descriptions relayed above, the following modifications can be adopted: sense region positions 1 and 2 and all Cs and Us have 2′-O-Me modifications, and all other 2′ positions of the sense region have 2′-OH groups, and wherein all Cs and Us of the antisense region are 2′-F modified, all other nucleotides of the antisense region have 2′-OH groups, and the nucleotide at position 1 of the antisense region is phosphorylated and there is a UU overhang attached to the 3′ end of the antisense region, wherein the internucleotide bond between the two nucleotides of the overhang as well as the first nucleotide of the overhang and the 3′ most antisense nucleotide of the duplexed region of the antisense strand is a phosphorothioate linkage; and a cholesterol moiety is attached to the 3′ end of the sense region by a C5 linker. In yet another embodiment, the siRNA has the same features as the aforementioned but the antisense strand has at least one 2′-O-Me modification instead of a 2′-F modification.
[0103] The pharmaceutically acceptable carrier may comprise one or more of excipients, such as vehicles adjuvants, pH adjusting and buffering agents, tonicity adjusting agents, stabilizers and wetting agents. Furthermore, in some embodiments, the siRNA is delivered in microcapsules, for example by coacervation techniques or by interfacial polymerization (e.g., hydroxymethylcellulose or gelatin-microcapsules and poly-(methylmethasylate) microcapsules, respectively) in colloidal drug delivery systems (for example, liposomes, microspheres, microemulsions, nano-particles, and nanocapsules or microemulsions).
[0104] The siRNA may be introduced into a cell or organism by any method that is now known or that comes to be known and that from reading this disclosure, persons skilled in the art would determine would be useful in connection with the present invention in enabling siRNA to cross the cellular membrane. These methods include, but are not limited to, any manner of transfection, such as, for example, transfection employing DEAE-Dextran, calcium phosphate, cationic lipids/liposomes, micelles, manipulation of pressure, microinjection, electroporation, immunoporation, use of vectors such as viruses, plasmids, cosmids, bacteriophages, cell fusions, and coupling of the polynucleotides to specific conjugates or ligands such as antibodies, antigens, or receptors, passive introduction, adding moieties to the siRNA that facilitate its uptake, and the like.
[0105] In another embodiment, the present invention features use of an siRNA that targets VEGFA in the manufacture of a medicament for treating, inhibiting or ameliorating one or more of the following conditions: psoriasis, cancer, rheumatoid arthritis, ocular neovascularization, abnormal angiogenesis, retinal vascular permeability, retinal edema, diabetic retinopathy (particularly proliferative diabetic retinopathy), diabetic macular edema, exudative age-related macular degeneration, sequela associated with retinal ischemia, and posterior segment neovascularization. Recipients of the siRNAs of the present invention may for example, be persons who are afflicted with one or more of the aforementioned disorders.
[0106] The dosage of the siRNA is preferably a therapeutically effective amount. A therapeutically effective amount will be determined at least in part by the age, weight and condition or severity of the affliction of the organism to be treated.
[0107] Examples of the siRNAs of the present invention may comprise an antisense sequence selected from SEQ ID NOs: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76, 78, 80, 82, 84, 86, and 88, and the corresponding sense strand in Table I.
[0000]
TABLE 1
shows the silencing activities of 42 unmodified siRNAs tested in
vitro as described in the Examples Section.
% VEGFA
% VEGFA
SEQ ID
Top: Sense Strand, 5′→3′
RNA
Protein
Seq. Ref.
NO:
Bottom: Antisense strand, 5′→3′
remaining
remaining
vegfa 2.1
1
UACUAAAUCUCUCUCCUUU
41.6
50.0
2
AAAGGAGAGAGAUUUAGUA
vegfa 2.2
3
ACAGAACGAUCGAUACAGA
22.5
20.6
4
UCUGUAUCGAUCGUUCUGU
vegfa 2.3
5
CGACAGAACAGUCCUUAAU
19.9
21.2
6
AUUAAGGACUGUUCUGUCG
vegfa 2.4
7
GAAGAGACACAUUGUUGGA
22.3
21.4
8
UCCAACAAUGUGUCUCUUC
vegfa 2.5
9
GUCACUAGCUUAUCUUGAA
13.6
31.6
10
UUCAAGAUAAGCUAGUGAC
vegfa 2.6
11
CAGCACACAUUCCUUUGAA
57.3
44.4
12
UUCAAAGGAAUGUGUGCUG
vegfa 2.9
13
GGAGACCACUGGCAGAUGU
24.1
37.5
14
ACAUCUGCCAGUGGUCUCC
VEGFA 2.11
15
GCUCGGUGCUGGAAUUUGA
51.0
35.1
16
UCAAAUUCCAGCACCGAGC
vegfa 2.12
17
GAAAGACAGAUCACAGGUA
20.8
27.8
18
UACCUGUGAUCUGUCUUUC
vegfa 2.14
19
CCAGAAACCUGAAAUGAAG
31
22.5
20
CUUCAUUUCAGGUUUCUGG
vegfa 2.15
21
GAGAAGAGACACAUUGUUG
36.6
20.5
22
CAACAAUGUGUCUCUUCUC
vegfa 2.17
23
CGACAAAGAAAUACAGAUA
40.8
40.0
24
UAUCUGUAUUUCUUUGUCG
vegfa 2.18
25
GGGCAAAUAUGACCCAGUU
12.2
39.8
26
AACUGGGUCAUAUUUGCCC
vegfa 2.19
27
GAAGAGAAGAGACACAUUG
43.3
21
28
CAAUGUGUCUCUUCUCUUC
vegfa 2.20
29
GAAACCAGCAGAAAGAGGA
47.6
44
30
UCCUCUUUCUGCUGGUUUC
vegfa 2.21
31
GAUCACAGGUACAGGGAUG
44.8
33.1
32
CAUCCCUGUACCUGUGAUC
vegfa 2.22
33
GGAAAGAGGUAGCAAGAGC
52
53.3
34
GCUCUUGCUACCUCUUUCC
vegfa 2.23
35
GAGAUGAGCUUCCUACAGC
88.5
14.7
36
GCUGUAGGAAGCUCAUCUC
vegfa 2.24
37
GAUCAAACCUCACCAAGGC
30.8
11.3
38
GCCUUGGUGAGGUUUGAUC
Vegfa 2.25
39
CAACAAAUGUGAAUGCAGA
22.0
5.52
40
UCUGCAUUCACAUUUGUUG
vegfa 3.1
41
AAAUGAAGGAAGAGGAGAC
16.2
9
42
GUCUCCUCUUCCUUCAUUU
vegfa 3.2
43
AAUGCAGACCAAAGAAAGA
25.3
11.5
44
UCUUUCUUUGGUCUGCAUU
vegfa 3.3
45
ACAUAGGAGAGAUGAGCUU
16.3
14.3
46
AAGCUCAUCUCUCCUAUGU
vegfa 3.4
47
ACGACAAAGAAAUACAGAU
32.6
52.4
48
AUCUGUAUUUCUUUGUCGU
vegfa 3.5
49
AGACACACCCACCCACAUA
17.6
26.1
50
UAUGUGGGUGGGUGUGUCU
vegfa 3.6
51
AGACAUUGCUAUUCUGUUU
31.4
25.7
52
AAACAGAAUAGCAAUGUCU
vegfa 3.7
53
AGAGAAAAGAGAAAGUGUU
23.4
9.8
54
AACACUUUCUCUUUUCUCU
vegfa 3.8
55
AGCACACAUUCCUUUGAAA
26.6
42
56
UUUCAAAGGAAUGUGUGCU
vegfa 3.9
57
CAAAUGUGAAUGCAGACCA
45.8
35.4
58
UGGUCUGCAUUCACAUUUG
vegfa 3.10
59
CACACAUUCCUUUGAAAUA
39.3
28.3
60
UAUUUCAAAGGAAUGUGUG
vegfa 3.11
61
CAGAACAGUCCUUAAUCCA
22.9
34.4
62
UGGAUUAAGGACUGUUCUG
vegfa 3.12
63
CAGAGAAAAGAGAAAGUGU
30.1
30.7
64
ACACUUUCUCUUUUCUCUG
vegfa 3.13
65
CCAGCACAUAGGAGAGAUG
34.7
22.3
66
CAUCUCUCCUAUGUGCUGG
vegfa 3.16
67
CGAGAUAUUCCGUAGUACA
32.8
61
68
UGUACUACGGAAUAUCUCG
vegfa 3.17
69
CUACUGUUUAUCCGUAAUA
40.9
55.2
70
UAUUACGGAUAAACAGUAG
vegfa 3.18
71
CUGAAAUGAAGGAAGAGGA
43.5
43
72
UCCUCUUCCUUCAUUUCAG
vegfa 3.19
73
GAAAUGAAGGAAGAGGAGA
42.7
48.3
74
UCUCCUCUUCCUUCAUUUC
vegfa 3.20
75
GAACAGUCCUUAAUCCAGA
25.9
30.9
76
UCUGGAUUAAGGACUGUUC
vegfa 3.21
77
GAGAGAUGAGCUUCCUACA
64.6
33
78
UGUAGGAAGCUCAUCUCUC
vegfa 3.22
79
GAGAUAUUCCGUAGUACAU
60.5
61.3
80
AUGUACUACGGAAUAUCUC
vegfa 3.23
81
GAGGCAGAGAAAAGAGAAA
26.9
32.4
82
UUUCUCUUUUCUCUGCCUC
vegfa 3.24
83
GAUAUUAACAUCACGUCUU
37.8
73.5
84
AAGACGUGAUGUUAAUAUC
vegfa 3.25
85
GCACACAUUCCUUUGAAAU
18.8
38.1
86
AUUUCAAAGGAAUGUGUGC
vegfa 3.26
87
GCGGAUCAAACCUCACCAA
30
33.5
88
UUGGUGAGGUUUGAUCCGC
[0000]
TABLE 2
shows the silencing activity of a selection of siRNAs in unmodified and siStable
modified formats. Specifically, data in columns D and E are derived from unmodified
molecules at 24 hours. Data in columns F, G, H, and I are derived from siStable
modified molecules at 72 hours. Data in columns F and G were derived when siRNA were
transfected into cells at 100 nM concentrations.
B
D
E
F
G
H
I
A
SEQ
C
RNA
protein
siStable
siStable
RNA
protein
Seq.
ID
Top: Sense Strand, 5′→3′
IC 50
IC 50
% RNA
% protein
IC 50
IC 50
Ref.
NO:
Bottom: Antisense strand, 5′→3′
(nM)
(nM)
remaining
remaining
(nM)
(nM)
vegfa
1
UACUAAAUCUCUCUCCUUU
0.31
0.51
17
41
4.78
2.35
2.1
2
AAAGGAGAGAGAUUUAGUA
vegfa
41
AAAUGAAGGAAGAGGAGAC
5.2
0.82
18
12
0.36
0.15
3.1
42
GUCUCCUCUUCCUUCAUUU
vegfa
43
AAUGCAGACCAAAGAAAGA
0.93
0.17
10
9
0.4
0.37
3.2
44
UCUUUCUUUGGUCUGCAUU
vegfa
45
ACAUAGGAGAGAUGAGCUU
0.43
0.59
11
10
0.82
0.77
3.3
46
AAGCUCAUCUCUCCUAUGU
vegfa
51
AGACAUUGCUAUUCUGUUU
0.81
0.94
28
31
23
3.17
3.6
52
AAACAGAAUAGCAAUGUCU
vegfa
53
AGAGAAAAGAGAAAGUGUU
1.3
0.46
10
10
0.26
0.46
3.7
54
AACACUUUCUCUUUUCUCU
vegfa
59
CACACAUUCCUUUGAAAUA
1.05
0.97
13
20
0.26
0.17
3.10
60
UAUUUCAAAGGAAUGUGUG
vegfa
63
CAGAGAAAAGAGAAAGUGU
4.6
1
10
15
0.11
0.21
3.12
64
ACACUUUCUCUUUUCUCUG
vegfa
75
GAACAGUCCUUAAUCCAGA
2
0.62
9
28
0.31
0.53
3.20
76
UCUGGAUUAAGGACUGUUC
vegfa
81
GAGGCAGAGAAAAGAGAAA
1.4
1.2
14
45
2.2
2.7
3.23
82
UUUCUCUUUUCUCUGCCUC
[0108] It is noted that the above recited duplexes do not contain mismatches. The present invention includes the specifically recited siRNAs as well as pharmaceutical compositions that contain them and methods for using them. The present invention also includes siRNAs that are similar to them but have a different base at position 6 or position 13 or position 19 of the sense strand or at both positions 6 and 13 or both of positions 13 and 19 or at both of positions 6 and 19 of the sense strand or at all three of positions, 6, 13 and 19 of the sense strand. Thus at any of those three positions, wherein in tables 1 or 2 there is an A complementary to a U, a U, C or G may be inserted, wherein in tables 1 or 2 there is an U complementary to an A, an A, C or G may be inserted, wherein in tables 1 or 2 there is a C complementary to a G, a U, A or G may be inserted, wherein in tables 1 or 2 there is a G complementary to a C, a U, C or A may be inserted. Still further, any of these siRNAs may contain overhang regions, e.g., a UU 3′ antisense overhang and/or a UU 3′ sense overhang.
[0109] By way of further example, in one embodiment, the present invention is directed to an siRNA from Table 2, or to an siRNA that differs from that of table 2 in that the sense strand has three mismatched nucleotides that are located at positions, 6, 13, and 19 with the opposite nucleotides on the antisense e.g., an siRNA that contains the sense and antisense sequences of vegfa 3.7, except that the sense strand has three mismatched nucleotides that are located at positions, 6, 13, and 19. In some embodiments the mismatches are selected such that one or more, for example, two or three of the mismatched bases are the same as the bases on the opposite strand and no other mismatched bases are present in the duplex. By way of a non-limiting example, for vegfa 3.7 a duplex may be
[0000]
SS-
5′ AGAGAUAAGAGAUAGUGUA 3′
(SEQ ID No: 91)
AS-
3′ UCUCUUUUCUCUUUCACAA 5′
(SEQ ID No: 54)
[0110] This duplex, as well as any other duplex disclosed herein, may contain 3′ overhangs on either the sense strand or the antisense strand. By way of a non-limiting example, there may be a dinucleotide overhangs, e.g., UU. This overhang may exist on the sense strand, but not the antisense strand; on the antisense strand but not the sense strand; on both strands or on neither strand. Each overhang may be constructed to have a standard internucleotide linkage between nucleotides of the overhang and a standard linkage to the 3′ end of the appropriate strand of the duplex, or in the overhang, the bond between the two nucleotides of the overhang as well as the first nucleotide of the overhang and the 3′ most antisense nucleotide of the duplexed region of the strand is a phosphorothioate linkage. Thus, e.g., in the vegfa 3.7 duplex of the preceding paragraph, SEQ ID No: 54 may contain a UU 3′ antisense overhang that does not contain a phosphorothioate linkage between the nucleotides of the overhang or between the overhang and the 3′ of SEQ ID No: 54, or there may be phosphorothioate linkages at one or both of those positions.
[0111] Unless otherwise specified, each of the features of each of the aforementioned embodiments may be used in connection with any of the other embodiments, unless such use is incompatible or inconsistent with that embodiment.
[0112] Having described the invention with a degree of particularity, examples will now be provided. These examples are not intended to and should not be construed to limit the scope of the claims in any way.
EXAMPLES
Example 1
General Techniques for In Vitro Studies
[0113] siRNA Selection for Study
[0114] A collection of siRNAs capable of targeting all the variants of VEGFA were identified (NM — 001025366, NM — 003376, NM — 001025367, NM — 001025368, NM — 001033756, NM — 001025369, NM — 001025370). Table 1 provides a list of the siRNAs along with the sense and antisense strand sequences (5′→3′).
[0115] To assess the relative functionality of each siRNA, sequences were synthesized using 2′ ACE chemistry (U.S. Pat. No. 6,008,400; U.S. Pat. No. 6,111,086; U.S. Pat. No. 6,590,093; Scaringe (2000) Methods in Enzymology 317:3-18; Scaringe (2001) Methods 23(3):206-217) and then transfected into HeLa cells (ATCC, #CCL-2) by lipid mediated transfection using the manufacturer's protocols (10,000 cells per well in a 96 well format, 100 nM siRNA, 0.2 μl DharmaFECT 1/well). Seventy-two hours post-transfection, overall cell viability and target knockdown at the mRNA and protein level was determined. All assays were performed in triplicate and for a select group of siRNAs, a dose curve (0.001, 0.01, 0.1, 1.0, 10.0, and 100 nM) was performed to ascertain the IC 50 for the siRNA/target mRNA pair. Positive and negative controls were included in all experiments and consisted of a non-targeting control (NTC #5 sense strand sequence: 5′-UGGUUUACAUGUCGACUAAUU-3′ (SEQ ID NO: 89)) and a positive control targeting PPIB (sense strand sequence: 5′-ACAGCAAAUUCCAUCGUGU-3′ (SEQ ID NO: 90)). Note: the positive control molecule used in these studies contains the following modifications: sense strand contains a 2′-O-methyl modification on the first two nucleotides counting from the 5′ end of the strand; antisense strand contains a 5′ phosphate group; both sense and antisense strands contain a 2 nucleotide UU overhang on the 3′ end.
[0116] Target mRNA and Protein Knockdown Analysis
[0117] Target mRNA knockdown was determined at 72 hour post-transfection using the branched DNA assay (QuantiGene Screen Kit, Panomics). The expression of PPIB was used as a reference mRNA and the targeted mRNA knockdown was further normalized to the corresponding non-targeting control (NTC). Protein expression was assessed by performing a VEGFA ELISA assay on supernatants from transfected cells at 72 hours post-transfection. The ELISA was performed according to the manufacturer's instructions using 50 μL of supernatant (Human VEGFA ELISA kit, Thermo Scientific). Absorbance was read on a spectrophotometer at 450 nM. Data was normalized to the corresponding NTC control.
[0118] Cell Viability Assay
[0119] Cell viability was assessed by a resazurin assay at 72 hours post-transfection. Resazurin was added directly into the culture media and the plates were incubated for 1-1.5 hours prior to measuring the fluorescence on a Wallac VICTOR 2 (Perkin Elmer Life Sciences) plate reader (Excitation 530 nm, Emission 590 nm and 1 second exposure). Data was normalized to the corresponding NTC control.
[0120] siRNA Designs for Study
[0121] siRNA configurations tested in the in vitro studies include (1) the standard unmodified design (19 base pairs duplex, UU overhangs on the 3′ end of both sense and antisense strands), and (2) the stabilized design (a 19 base pair duplex; sense strand modifications: 2′-O-methyl modifications on nucleotides 1 and 2 (counting from the 5′ end of the strand) plus 2′-O-methyl modifications on all Cs and Us; antisense strand modifications: a phosphate on the 5′ terminal nucleotide, 2′ F modifications on all Cs and Us, a 2 nucleotide (UU) overhang on the 3′ terminus, and a phosphorothioate internucleotide modification between the two nucleotides of the overhang and between the first (3′ most) nucleotide of the duplex and the first nucleotide of the overhang).
[0122] For in vivo studies, siRNAs included the following design:
a 19 bp duplex sense strand modifications
2′-O-methyl modifications on nucleotides 1 and 2 (counting from the 5′ end of the strand) 2′-O-methyl modifications on all Cs and Us cholesterol conjugated to the 3′ terminus using a C5 linker (see U.S. Pat. Pub. 2009/0209626, published Aug. 20, 2009 the disclosure of which is incorporated by reference as if set forth fully herein)
antisense strand modifications
5′ phosphate 2′ F on all Cs and Us a two nucleotide (UU) overhang on the 3′ terminus phosphorothioate internucleotide modifications between the two nucleotides of the overhang and between the first (3′ most) nucleotide of the duplex and the first nucleotide of the overhang.
[0133] In addition, mismatches at positions 6, 13, and 19 have been incorporated into molecules used in in vivo studies. In all cases, mismatches between the two strands of the siRNA are achieved by changing the nucleotide of the sense strand to have identity with the base (on the antisense strand) that typically pairs with that position. Thus, for instance, if the sense-antisense pair at sense strand position 6 is normally U-A, then the mismatch will be introduced by converting the pair to A-A. Similarly, if the sense-antisense pair at sense strand position 6 is G-C, then the mismatch will be C—C. In this way, a mismatch is incorporated into the duplex, but the antisense strand remains the reverse complement of the intended target.
Example 2
Results of In Vitro and In Vivo Studies
[0134] The performance of all the sequences tested in vitro is shown in Table 1. Multiple sequences were observed to provide greater than 70% gene knockdown at both the RNA and protein level including, for instance, Vegfa 2.2, 2.3, 2.4, 2.12, 3.1, 3.2, 3.3, 3.5, and 3.7. In addition, when a subset of the collection was tested with the stabilized design, overall performance was found to be equivalent or better than that observed in the unmodified state (see, for instance, vegfa 2.1, 3.2, 3.3). As Table 2 shows, in both the unmodified and modified states, IC 50 for RNA knockdown ranged from approximately 0.11→23 nM while IC 50 for protein knockdown ranged from ˜0.17→3.17 nM. Based on these results, two sequences, Vegfa 3.2 and 3.7, were re-synthesized using the in vivo design (referred to as “Accell”) described previously. The results of these experiments may be further demonstrated by reference to the accompanying figures.
[0135] FIGS. 1A and 1B illustrate the effect of intravitreal (IVT) injection of Accell VEGFA siRNAs on expression of VEGFA mRNA and protein, respectively, in the rat retina at 72 h post-injection. Lewis rats received 10 μg IVT injections (OD) of Accell VEGFA 3.2, Accell VEGFA 3.7 or Accell non-targeting control #1 (NTC1) siRNAs resuspended in 1× siRNA buffer (Dharmacon). The Accell NTC1 siRNA sense strand sequence is 5′-UGGUUAACAUGUCGACUAA-3′ (SEQ ID NO: 92); the Accell NTC1 siRNA antisense strand sequence is 5′-UUAGUCGACAUGUAAACCAUU-3′ (SEQ ID NO: 93). Contralateral eyes (OS) were not treated. Eyes were harvested at 72 h post-injection, and retinas were isolated by dissection. ( 1 A) Total RNA was extracted using Trizol (Invitrogen), and VEGFA and β-actin (ACTB) mRNA levels were determined by Taqman qRT-PCR assay (Applied Biosystems). VEGFA mRNA expression was normalized to β-actin expression. ( 1 B) Protein was extracted using RIPA buffer (Pierce), and rat VEGFA protein level was determined by ELISA (R&D Systems). VEGFA protein expression was normalized to total protein determined by BCA assay (Pierce). Data are presented as the mean (n=6)±standard deviation (error bars). *, P<0.001 versus NTC1. Both of the VEGFA siRNAs significantly reduced the expression of VEGFA mRNA; VEGFA 3.7 also significantly reduced VEGFA and protein. The NTC1 control siRNA had little, if any, effect on VEGFA expression.
[0136] FIG. 2 shows a comparison between the dose response curves for Accell VEGFA 3.2 siRNA and a control siRNA in the rat retina. Lewis rats received 1-25 μg IVT injections (OD) of Accell VEGFA 3.2 or Accell NTC1 control siRNAs resuspended in 1× siRNA buffer (Dharmacon). Contralateral eyes (OS) were not treated. Eyes were harvested at 72 h post-injection, and retinas were isolated by dissection. Total RNA was extracted using Trizol Plus (Invitrogen), and VEGFA and β-actin mRNA levels were determined by Taqman qRT-PCR assay (Applied Biosystems). VEGFA mRNA expression was normalized to β-actin mRNA. Data are presented as the mean OD:OS ratio (ratio of VEGFA level in the treated eye versus the non-treated eye) for normalized VEGFA mRNA expression (n=6)±standard deviation (error bars). *, P<0.05; **, P<0.01 versus Accell NTC1. Intravitreal injection of increasing amounts of Accell VEGFA siRNA 3.2 resulted in a dose response that reached essentially complete silencing of VEGFA mRNA expression at 25 μg.
[0137] FIGS. 3A and 3B shows a comparison between the dose response curves for Accell VEGFA 3.7 siRNA and a control siRNA in the rat retina. Lewis rats received 1-50 μg IVT injections (OD) of Accell VEGFA 3.7 siRNA or Accell VEGFA 3.7 cleavage site mismatch (CS MM) control siRNAs resuspended in 1× siRNA buffer (Dharmacon). The Accell VEGFA 3.7 CS MM control siRNA has the same sequence as Accell VEGFA 3.7 siRNA except for a 3-nucleotide mismatch to the VEGFA mRNA target sequence. The Accell VEGFA 3.7 CS MM siRNA sense strand sequence is 5′-AGAGAUAACUCAUAGUGUA-3′ (SEQ ID NO: 94); the Accell VEGFA 3.7 CS MM siRNA antisense strand sequence is 5′-AACACUUUGAGUUUUCUCUUU-3′ (SEQ ID NO: 95). Contralateral eyes (OS) were not treated. Eyes were harvested at 72 h post-injection, and retinas were isolated by dissection. ( 3 A) Total RNA was extracted using Trizol (Invitrogen), and VEGFA and β-actin mRNA levels were determined by Taqman qRT-PCR assay (Applied Biosystems). VEGFA mRNA expression was normalized to β-actin mRNA expression. ( 3 B) Protein was extracted using RIPA buffer (Pierce), and rat VEGF-A level was determined by ELISA (R&D Systems). VEGFA protein expression was normalized to total protein level determined by BCA assay (Pierce). Data are presented as the mean OD:OS ratio for normalized VEGFA mRNA or protein expression (n=6)±standard deviation (error bars). *, P<0.03; **, P<0.0002; #, P<0.005. Intravitreal injection Accell VEGFA 3.7 siRNA at doses as low as 5 μg caused a significant reduction in VEGFA expression at both the mRNA and protein levels. The Accell VEGFA 3.7 siRNA exhibited a dose response that reached >70% inhibition of VEGFA mRNA expression and approximately 80% inhibition of VEGFA protein expression at 25 μg siRNA. Non-RNAi-mediated inhibition of VEGFA expression was also observed with the control siRNA. This effect was less pronounced for VEGFA protein than for VEGFA mRNA.
[0138] FIGS. 4A and 4B show the time duration of action for the Accell VEGFA 3.7 siRNA. Lewis rats received 25 μg IVT injections (OD) of Accell VEGFA 3.7 siRNA or Accell NTC1 control siRNAs resuspended in 1× siRNA buffer (Dharmacon). Contralateral eyes (OS) were not treated. Eyes were harvested at 1, 3, 7, 14, 28, 42, and 56 d post-injection, and retinas were isolated by dissection. Expression of VEGFA mRNA ( 4 A) and VEGFA protein ( 4 B) was evaluated as described in the previous examples. Data are presented as the mean OD:OS ratio for normalized VEGFA mRNA or protein expression (n=6)±standard deviation (error bars). *, P<0.001; #, P<0.002 versus NTC1. Intravitreal injection of Accell VEGFA 3.7 siRNA caused significant inhibition of VEGFA mRNA and protein expression within 24 h. Inhibition persisted for several weeks.
[0139] FIGS. 5A and 5B show inhibition of VEGFA protein expression and preretinal neovascularization, respectively, in the rat oxygen-induced retinopathy (OIR) model (modified from Penn et al., Pediatr. Res. 36:724-731, 1994). Following 14 d of cycling between 50% and 10% O 2 , neonatal Sprague Dawley rats were exposed to room air (21% O 2 ) for 7 d (postpartum days 15-21, P15-P21). On days P15 and P18, animals received 25 μg IVT injections (OS) of Accell VEGFA siRNA 3.7 or Accell VEGFA 3.7 CS MM control siRNA resuspended in 1× siRNA buffer (Dharmacon). Contralateral eyes (OD) were treated with vehicle (1× siRNA buffer). Injection volume was 1 μl. Eyes were harvested on day P21, and retinas were isolated by dissection. ( 5 A) Protein was extracted using RIPA buffer (Pierce), and VEGFA protein level was determined by ELISA (R&D Systems). VEGFA protein expression was normalized to total protein level determined by BCA assay (Pierce). Data are presented as mean normalized VEGFA protein expression (n=7)±standard deviation (error bars). *, P<0.03. ( 5 B) Retinas were fixed in 10% neutral buffered formalin for 24 h, subjected to ADPase staining, and fixed onto slides as whole mounts. Images were acquired using a Nikon Coolscope®, and each of 12 sectors per retina was assessed for the presence or absence of neovascularization to obtain a clockhour score (n=6-8). #, P<0.05. The Accell VEGFA 3.7 siRNA caused a significant reduction in VEGFA protein expression (˜40%), resulting in an approximately 88% inhibition of preretinal neovascularization. The Accell VEGFA 3.7 CS MINI control siRNA did not have a significant effect on either VEGFA expression or neovascularization.
[0140] As persons of ordinary skill in the art are aware, extrapolating to humans, observations made in rats is well-known.
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Vascular endothelial growth factor A (VEGFA) is a chemical signal produced by cells that stimulates the growth of new blood vessels, and overexpression of VEGFA can lead to undesirable physiological conditions. Through the identification of new siRNA and modifications that improve the silencing ability of these siRNA in vivo, therapeutic compositions and methods have been invented to address the problems associated with this overexpression.
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[0001] This application is based on Applications No. 173149 filed in Japan on Jun. 7, 2001, and No. 153102 filed in Japan on May 27, 2002, the content of which is incorporated hereunto by reference.
BACKGROUND OF THE INVENTION
[0002] This invention relates to a low speed electron beam phosphor primarily for use in field emission displays (referred to as FEDs in this patent application).
[0003] A FED is a flat panel display which excites phosphor material with low speed electron beams, and is configured with an anode and corresponding cathode. A phosphor film established at the anode-side is excited by electrons emitted from the cathode to cause light emission. The electron beam for excitation at the anode is accelerated by voltages on the order of 0.1 KV to 10 KV. This is a low accelerating voltage in comparison to the several tens of KV typical for cathode ray tubes (CRTs). Therefore, special purpose phosphor material, which is excited by low speed electron beams, is used in FED applications.
[0004] Since the accelerating voltage of the electron beam for phosphor excitation in a FED is low compared to a television CRT, electron beam energy for phosphor excitation is low. Low excitation energy electrons cannot cause a phosphor to emit high luminance light. Therefore, compared to a CRT, a FED produces bright light emission by increasing the current density of the phosphor exciting electron beam. If a CRT phosphor is used at high current densities, its lifetime is significantly reduced. Consequently, although various colors of phosphors for use with televisions have been tried, almost none have been usable for FED applications.
[0005] (Y, Ce) 2 O 3 .SiO 2 phosphor has been developed as a phosphor for FED applications allowing high current densities. This phosphor emits blue light. The raw material for a phosphor of this composition is formed by incorporating SiO 2 particulates in a mixture of yttrium oxide (Y 2 O 3 ) and cerium dioxide (CeO 2 ). Phosphor is produced by firing the raw material in a crucible. Phosphor raw material is mixed and fired to result in (Y, Ce) 2 O 3 and SiO 2 with a mole ratio of 1, namely with a stoichiometric mixture.
[0006] (Y, Ce) 2 O 3 .SiO 2 phosphor fired in this fashion cannot be formed with a uniform distribution of constituents at the surface and internally. The fired phosphor has excessive SiO 2 near the surface of phosphor particles. This is because yttrium oxide (Y 2 O 3 ) and cerium dioxide (CeO 2 ) form the core of a phosphor particle and SiO 2 gradually permeates inward from the surface with firing. Excess surface SiO 2 is the cause of electron beam induced luminance degradation for (Y, Ce) 2 O 3 .SiO 2 phosphor fired in this fashion. A phosphor with high luminance degradation characteristics does not only mean lifetime is shortened when the phosphor is used alone. When used together with other phosphors, it can cause changes in emission colors, For example, (Y, Ce) 2 O 3 .SiO 2 blue phosphor is used together with (Y, Tb) 2 SiO 5 green phosphor and (Y, Eu) 2 O 3 red phosphor as a white phosphor material. However, luminance and lifetime characteristics of (Y, Ce) 2 O 3 .SiO 2 blue phosphor are not the same as those of red and green phosphors such as these. As a result, a monochromatic phosphor formed by mixing these kinds of phosphors has the drawback that emission color changes over use.
[0007] The present invention was developed to resolve these drawbacks. It is thus a primary object of the present invention to provide a (Y, Ce) 2 O 3 .SiO 2 phosphor for use with low speed electron beams which has superior lifetime and luminance characteristics.
[0008] The above and further objects and features of the invention will more fully be apparent from the following detailed description with accompanying drawings.
SUMMARY OF THE INVENTION
[0009] The phosphor for use with low speed electron beams of this invention is represented by the following general composition formula.
(Y, Ce) 2 O 3 .nSiO
[0010] Here, the value of n is in the range 0.4≦n<1.0. The value of n in this formula determines the lifetime characteristics of the (Y, Ce) 2 O 3 .SiO 2 phosphor. A phosphor with a small value of n has improved lifetime characteristics, and a phosphor with large n has worse lifetime characteristics. To improve lifetime characteristics, the value of n should be made small. However, the value of n also affects emission luminance, and values below 0.4 decreases luminance. Consequently, the above mentioned range of n is established considering luminance and lifetime characteristics, and more preferably the range of n is 0.5≦n≦0.9.
[0011] Further, the phosphor for use with low speed electron beams of this invention can also be represented by the following general composition formula, and the range of values for a and n are given by the expressions below.
(Y 1−a , Ce a ) 2 O 3 .nSiO 2
0.001≦a≦0.05
0.4≦n< 1 . 0
[0012] The value of a in the formula affects the phosphor's emission luminance and color. If a is either too large or too small, the phosphor's emission luminance drops off. This is because luminance improvement due to Ce inclusion is ineffective below 0.001, and because optical quenching due to high concentrations occurs above 0.05. The value of a in the composition formula is set considering phosphor luminance and color, preferably in the above mentioned range. A still more preferable range is 0.005≦a≦0.04.
[0013] The (Y, Ce) 2 O 3 .SiO 2 phosphor for use with low speed electron beams described above is characterized by significant Improvement in lifetime characteristics compared to related art phosphors. This is because excessive SiO 2 at the phosphor surface, which causes luminance degradation, is reduced by making the SiO 2 to (Y, Ce) 2 O 3 ratio less than 1. The exceptional lifetime characteristics of the (Y, Ce) 2 O 3 .SiO 2 phosphor described above are shown in Table 1. For example, luminance after 1000 hrs was 45% to 70% of initial luminance for embodiment phosphors. This is radical improvement compared to 30% to 35% for prior art phosphors. In addition, superior emission luminance over prior art phosphors is also shown in Table 1. When luminance of the phosphor of comparison example 1 is taken to be 100%, luminance of embodiments 1 through 35 are considerably improved at 100% to 145%.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] [0014]FIG. 1 is a graph showing residual ratio of luminance while varying n in the general composition formula, and where the value of a is 0.010. Here, residual ratio of luminance for the phosphors of embodiments 1 through 5 are shown.
[0015] [0015]FIG. 2 is a graph showing relative luminance compared to the phosphor of comparison example 1 while varying n in the general composition formula, and where the value of a is 0.010. Here, relative luminance for the phosphors of embodiments 1 through 5 are shown.
[0016] [0016]FIG. 3 is a graph showing relative luminance compared to the phosphor of comparison example 1 while varying n in the general composition formula, and where the value of a is 0.020. Here, relative luminance for the phosphors of embodiments 6 through 10 are shown.
[0017] [0017]FIG. 4 is a graph showing relative luminance compared to the phosphor of comparison example 1 while varying n in the general composition formula, and where the value of a is 0.030. Here, relative luminance for the phosphors of embodiments 11 through 15 are shown.
[0018] [0018]FIG. 5 is a graph showing residual ratio of luminance while varying n in the general composition formula, and where the value of a is 0.040. Here, residual ratio of luminance for the phosphors of embodiments 16 through 20 are shown.
[0019] [0019]FIG. 6 is a graph showing relative luminance compared to the phosphor of comparison example 1 while varying n in the general composition formula, and where the value of a is 0.040. Here, relative luminance for the phosphors of embodiments 16 through 20 are shown.
[0020] [0020]FIG. 7 is a graph showing relative luminance compared to the phosphor of comparison example 1 while varying n in the general composition formula, and where the value of a is 0.001. Here, relative luminance for the phosphors of embodiments 21 through 25 are shown.
[0021] [0021]FIG. 8 is a graph showing residual ratio of luminance while varying n in the general composition formula, and where the value of a is 0.005. Here, residual ratio of luminance for the phosphors of embodiments 26 through 30 are shown.
[0022] [0022]FIG. 9 is a graph showing relative luminance compared to the phosphor of comparison example 1 while varying n in the general composition formula, and where the value of a is 0.005. Here, relative luminance for the phosphors of embodiments 26 through 30 are shown.
[0023] [0023]FIG. 10 is a graph showing relative luminance compared to the phosphor of comparison example 1 while varying n in the general composition formula, and where the value of a is 0.050. Here, relative luminance for the phosphors of embodiments 31 through 35 are shown.
[0024] [0024]FIG. 11 is a graph showing relative luminance compared to the phosphor of comparison example 1 while varying a in the general composition formula, and where the value of n is 0.9. Here, relative luminance for the phosphors of embodiments 1, 6, 11 16, 21, 26, and 31 are shown.
[0025] [0025]FIG. 12 is a graph showing relative luminance compared to the phosphor of comparison example 1 while varying a in the general composition formula, and where the value of n is 0.8. Here, relative luminance for the phosphors of embodiments 2, 7, 12, 17, 22, 27 and 32 are shown.
[0026] [0026]FIG. 13 is a graph showing relative luminance compared to the phosphor of comparison example 1 while varying a in the general composition formula, and where the value of n is 0.7. Here, relative luminance for the phosphors of embodiments 3, 8, 13, 18, 23, 28 and 33 are shown.
[0027] [0027]FIG. 14 is a graph showing relative luminance compared to the phosphor of comparison example 1 while varying a in the general composition formula, and where the value of n is 1. Here, relative luminance for the phosphors of embodiments 1 through 3 are shown.
DETAILED DESCRIPTION OF THE INVENTION
Embodiments
[0028] [Embodiment 1]
[0029] (1) The following raw materials are prepared.
[0030] co-precipitate oxides formed by the method below 100 g
[0031] micro-silica (SiO 2 ) 23.9 g
[0032] Co-precipitate oxides, Y 0.99 , Ce 0.01 ) 2 O 3 , are produced by the following process steps.
[0033] 1) 111.8 g of Y 2 O 3 and 1.7 g of CeO 2 are dissolved in an aqueous solution of HNO 3 ,
[0034] 2) An aqueous solution of 500 g of oxalic acid is added to the solution from 1) while stirring. The precipitate formed is separated by Nutsche funnel and washed in water.
[0035] 3) Oxalate formed from 2) is put in a quartz crucible, covered, and fired for 15 hrs at 900° C. to produce the co-precipitate oxides, (Y 0.99 , Ce 0.01 ) 2 O 3 .
[0036] (2) The co-precipitate oxides, micro-silica (SiO 2 ), 200 ml of ethanol, and 200 g of aluminum balls are put together in a magnetic pot and milled for 2 hrs.
[0037] (3) Raw materials are removed from the magnetic pot, transferred to a vat, heat treated at 105° C., and dried. The mixed phosphor raw materials are obtained in this process step.
[0038] (4) The mixed raw materials are inserted in an aluminum crucible. The crucible is covered and fired for 3 hrs at 1500° C.
[0039] (5) After cooling, the fired contents of the crucible are removed, inserted into a polyvinyl jar with 400 ml of water and 200 g of beads, and the polyvinyl jar is rotated to grind the fired material, Next, the contents are removed from the polyvinyl jar and passed through a 200 mesh nylon filter to remove large phosphor particles. Finally, fluid is decanted, and after drying and further filtering, phosphor material with the following composition is obtained.
(Y 0.990 , Ce 0.010 ) 2 .0.9SiO 5
[0040] [Embodiments 2 through 35]
[0041] Phosphors with composition shown in Table 1 are produced in the same manner as embodiment 1 except the composition of co-precipitate oxides and the amount of added micro-silica (SiO 2 ) are changed.
COMPARISON EXAMPLE 1
[0042] A phosphor with the following composition is produced in the same manner as embodiment 1 except the amount of micro-silica (SiO 2 ) added and mixed with 100 g of co-precipitate oxides is 26.59 instead of 23.9 g.
Y 0.995 , Ce 0.010 ) 2 .SiO 5
COMPARISON EXAMPLE 2
[0043] A phosphor with the following composition is produced in the same manner as comparison example 1 except the co-precipitate oxides are (Y 0.995 , Ce 0.005 ) 2 O 3 instead of (Y 0.990 , Ce 0.010 ) 2 O 3.
(Y 0.995 , Ce 0.005 ) 2 .SiO 5
COMPARISON EXAMPLE 3
[0044] A phosphor with the following composition is produced in the same manner as comparison example 1 except the co-precipitate oxides are (Y 0.960 , Ce 0.040 ) 2 O 3 instead of (Y 0.990 , Ce 0.010 ) 2 O 3
(Y 0.960 , Ce 0.040 ) 2 .SiO 5 TABLE 1 General formula (Y 1.a , Ce a ) 2 O 3 .nSlO 2 Relative Residual Ratio of Luminance Luminance a N (%) (%) embodiment 1 0.010 0.9 115 45 embodiment 2 0.010 0.8 120 65 embodiment 3 0.010 0.7 115 70 embodiment 4 0.010 0.6 110 70 embodiment 5 0.010 0.5 105 70 embodiment 6 0.020 0.9 140 45 embodiment 7 0.020 0.8 145 65 embodiment 8 0.020 0.7 140 70 embodiment 9 0.020 0.6 135 70 embodiment 10 0.020 0.5 130 70 embodiment 11 0.030 0.9 140 45 embodiment 12 0.030 0.8 145 65 embodiment 13 0.030 0.7 140 70 embodiment 14 0.030 0.6 135 70 embodiment 15 0.030 0.5 130 70 embodiment 16 0.040 0.9 115 45 embodiment 17 0.040 0.8 110 65 embodiment 18 0.040 0.7 105 70 embodiment 19 0.040 0.6 103 70 embodiment 20 0.040 0.5 100 70 embodiment 21 0.001 0.9 100 45 embodiment 22 0.001 0.8 110 65 embodiment 23 0.001 0.7 105 70 embodiment 24 0.001 0.6 103 70 embodiment 25 0.001 0.5 100 70 embodiment 26 0.005 0.9 105 45 embodiment 27 0.005 0.8 110 65 embodiment 28 0.005 0.7 110 70 embodiment 29 0.005 0.6 105 70 embodiment 30 0.005 0.5 103 70 embodiment 31 0.050 0.9 100 45 embodiment 32 0.050 0.8 110 65 embodiment 33 0.050 0.7 105 70 embodiment 34 0.050 0.6 103 70 embodiment 35 0.050 0.5 100 70 comparison 0.010 1.0 100 35 example 1 comparison 0.005 1.0 80 30 example 2 comparison 0.040 1.0 90 35 example 3
[0045] Measurement conditions for Table 1 are 3 kV electron beam accelerating voltage for phosphor excitation and 1.5 mA/cm 2 current density, which are representative of measured values for actual FED devices.
[0046] As this invention may be embodied in several forms without departing from the spirit of essential characteristics thereof, the present embodiment is therefore illustrative and not restrictive, since the scope of the invention is defined by the appended claims rather than by the description preceding them, and all changes that fall within the meets and bounds of the claims or equivalence of such meets and bounds thereof are therefore intended to be embraced by the claims.
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A phosphor for use with low speed electron beams is characterized by the following general composition formula.
(Y, Ce) 2 O 3 .nSiO 2
0.4≦n<1.0
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The invention concerns a process according to the precharacterizing portion of claim 1 .
[0003] The invention is more specifically concerned with relatively thin-walled pipes, and in particular those with a diameter in the range of approximately 100 to 3000 mm and a wall thicknesses of 1.5 to 6.0 mm. Such pipes are primarily employed for air lines or conduits, ventilation ducts, device housings and the like in ventilation, air conditioning and vacuum engineering, but are however also employed in process engineering.
[0004] 2. Description of the Related Art
[0005] There are various types of connections for tightly and securely connecting individual pipe segments with each other. These connections have different influences upon the economics and technical characteristics of the pipe system. Until now angled, flat or other profiled flanges have been employed which are manufactured separately and seated upon the pipe end, although advantages of flanges formed directly, that is, unitarily, as one piece on the pipe ends is readily apparent and thus a need for such formed-on flanges and rims exist. The reason that there is a need is due to the lack of an economically justifiable process for forming desirable flange shapes on the ends of, above all, mass-produced pipes. Until now only radially projecting ring rims with relatively low stability or radially projecting flanges, which are provided with holes for screwing, are formed onto the pipes. The latter is employed primarily for ventilator housings. The simple ring can be produced with two rollers using a beading and rim machine. The latter flat flanges with holes are produced in a press process. For this, the pipe body is caused to rotate with high rotational speed, which is possible only with very short pipe bodies such as axial ventilator housings. The pipe ends are inserted into a die or negative pattern of the flat flange to be formed. With a pressure lever, on the end of which a roller revolves, pressure is applied against the rapidly rotating pipe end until the material is caused to flow and lie against the negative pattern. The “pressure” process is somewhat similar to the deforming of clay using a potter's wheel. It is also used for the forming of ring flanges on short pipe rings, which are then subsequently seated upon a pipe end and secured thereto. This latter process is described, for example, in DE 196 32857 A1.
[0006] This known process is poorly suited to the formation of flanges directly onto pipe ends, since it is almost impossible and besides this dangerous to spin larger pipes with the necessary speed of rotation. Further, the energy required for many types of forming in the case of a wide variety of different pipes is much too high for an economical process. Above all, however, the manufacture of complex flange shapes, such as for example conical flanges or the like, is not possible due to the occurrence therein of cutbacks or inclusions, since in this case the mold or pattern cannot be removed again from the finished flange.
[0007] For the manufacture of boxes, frames, profiles, or channels with straight edges the so-called beveling process or pivot bend process is known. For this, a planar sheet metal plate is clamped or tensioned between a fixed lower member and a moveable upper member, and bent using a pivotable bending member. The great advantage therein is that during pivot bending an entire sheet metal segment can be raised, or as the case may, be curved, without any stretching. The sheet metal materials need flow only in the area of the edge being formed. All the remaining material remains completely unchanged. Thus, the edge profile without stretching and without any particular effort is precisely straight and free of tension. In contrast thereto, in the case of the above-discussed “pressing” the entire material is bent through and thereby unavoidable tensions are introduced. Accordingly, the energy required for pivot bending is substantially less.
SUMMARY OF THE INVENTION
[0008] The present invention is concerned with providing a process and a device for carrying out this process, in which the one-piece forming of even complicated flanges and rims not only on short pipes, but rather in particular also on long pipe segments, is economically possible.
[0009] This task is inventively solved with respect to the process by the characterizing features of claim 1 and with respect to the device by the characteristics of claim 5 .
[0010] The dependent claims are directed primarily to advantageous embodiments of the invention.
[0011] It is the basis of the inventive process to employ the advantages of the linear pivot process also in the case of bending at pipe ends. It is thus referred to herein as the circular-pivot-bending process.
[0012] The linear pivot bending process can obviously not be applied to round pipes without modification, since herein the edges to be produced are not straight or linear, but rather curved, and these curved edges are to be produced with various radii with as few change-outs in work tools as possible. The invention accomplishes this by circumferential clamping of the pipe ends from inside, for example by means of a clamping disk. This clamping disk in has a slightly smaller diameter than the pipe inner diameter prior to clamping. Following insertion into the pipe it is widened, that is, the diameter is increased, until it lies with its outer circumference tightly against the inner surface of the pipe wall. The clamping disk or other device used for clamping can be connected with a strong drive axle for imparting the rotational movement. The tight clamping of the pipe end is thus also simultaneously used for the rotation of the pipe, wherein naturally only substantially lower rotational speeds are necessary than in the case of the pressure process. It is necessary that sufficient friction is created between the inner surface of the pipe and the clamping device, for example clamping disk, such that the pipe can be rotated against the resistance of the bending tools.
[0013] It is on the other hand basically also possible to allow the pipe and the therewith rigidly connected parts of the device to remain stationary and to rotate the bending tools and the therewith rigidly connected parts about the pipe axis.
[0014] The subsequent bending out of a part of the projecting pipe piece to form a rim or flange about the circumference of the pipe piece being modified occurs continuously during the rotation of the pipe. For this, a pivotable bending jaw is preferably employed, which in its rest position lies against the inner side of the pipe end. Its axial breadth should be at least somewhat larger than the segment of the pipe end to be bent. Thereby it is ensured that the segment to be bent is raised as a whole, and not changed in its straight shape. Preferably the contact surface of the bending jaw on the pipe end should have the same radius as the inside of the pipe, such that the segment of the pipe end to be bent has a large surface area contact surface. In principle however a circular shape of the contact surface of the bending jaw, with a somewhat smaller radius than the inside of the pipe, is also possible. Since the pivotable bending jaws can bend respectively only one partial segment of the pipe circumference, the pipe must be caused to rotate in an even, slow rotation. When the pipe rotates, the bending jaws are slowly pivoted unto the position of the desired bending angle. This inventive process can thus be properly referred to as a circular-pivot-bending process.
[0015] In a preferred embodiment of the invention it is possible to additionally apply pressure upon the bending point of the pipe from the outer side of the pipe, preferably using a shaping roller or the like, wherein a tip of the shaping roller cross-section terminates at that location, where the pipe end is to be bent over. Thereby the shape of the bent edge (sharp or round) can be predetermined quite precisely. The remainder of the cross-sectional shape of the shaping roller is determined by the maximal angle of bending of the tip-stretch profile. Since substantial forces are applied upon the shaping roller during the bending process, a precondition for obtaining a clean bent-edge is thus a rigid mounting and positioning of the shaping roller. Preferably, the shaping roller and its mounting are connected to a fixed unit with the likewise fixed and non-rotating bending jaws and the drive means therefore, whereby the stability of the device is substantially increased.
[0016] In the case that high precision in the form of the shaped flange or rim is not required, it is possible in the case of relatively small pipe thicknesses, to bend these without using a shaping roller. In this case the curvature of the pipe wall there suffices to provides sufficient resistance to bending. Sharp bent edges are therein however not possible, and with the increase in the wall thickness the radius of the bent edge continuously increases.
BRIEF DESCRIPTION OF THE DRAWING
[0017] The sequence of steps of the inventive process, as well as preferred embodiments of the inventive device, will now be described in greater detail with reference to the figures. There is shown
[0018] FIGS. 1 - 12 the process steps of the inventive process on the basis inventive process, showing the steps for forming a conical flange on the end of a pipe, wherein the device parts shown schematically in side view serve only as an example of the results to be achieved by the process and wherein other or differently shaped designs can be achieved,
[0019] [0019]FIG. 13 a schematic side view of a first embodiment of the device for carrying out the inventive process in a first processing position,
[0020] [0020]FIG. 14 a side view of the device according to FIG. 13 in a second processing position,
[0021] [0021]FIG. 15 a side view of the device according to FIG. 13 in a third processing position,
[0022] [0022]FIG. 16 a schematic partial section along the line XVI-XVI in FIG. 13,
[0023] [0023]FIG. 17 a schematic frontal view of the clamping disk employed in accordance with the process shown in FIGS. 13 through 18,
[0024] [0024]FIG. 18 a schematic side view of the parts shown in FIG. 17,
[0025] [0025]FIG. 19 a schematic side view of a clamping disk, pipe and the parts of the drive device of the inventive device,
[0026] [0026]FIG. 20 a sectional side view, shown in reduced scale compared to FIG. 19, of a part of the components shown in FIG. 19,
[0027] [0027]FIGS. 21 and 22 an axial section or, as the case may be, schematic side view of a different embodiment of the clamping disk,
[0028] [0028]FIGS. 23 and 24 schematic side views of pipe, clamping disk, bending jaws and shaping rollers with different locations or positions of the bending jaws,
[0029] [0029]FIGS. 22 through 29 a schematic partial view of a clamping disk and a bending jaw in different bending positions with shaping rollers having differing cross-sections or, as the case may be, without shaping rollers,
[0030] [0030]FIGS. 30 and 31 partial broken away schematic oblique views of parts of an inventive device with pipe, clamping disk, shaping rollers and bending jaws in the resting or, as the case may be, bending position of the bending jaws,
[0031] [0031]FIG. 32 a partial oblique view corresponding to FIG. 30 but without pipe and shaping roller,
[0032] [0032]FIGS. 33 through 35 a partial representation according to FIG. 32 with respectively three differing embodiments of the bending jaws, and
[0033] [0033]FIG. 36 a schematic partial view of an embodiment with two inventive devices working simultaneously on both ends of a pipe.
DETAILED DESCRIPTION OF THE INVENTION
[0034] [0034]FIGS. 1 through 12 show respectively in schematic partial representation the process steps of the inventive process on one pipe end. FIG. 1 shows, for simplification, a largely broken away partial sectional view through an unprocessed pipe 12 with circular cross-section and with end 10 facing towards the right in FIG. 1. FIG. 2 shows the condition of the pipe end 10 following the first processing step. The pipe end 10 has become a pipe piece to be further bent, which presently is bent outwards approximately 150° about a rounded-off bending edge 14 relative to the axial direction 16 of the pipe 12 . FIG. 3 shows the condition of the pipe 12 following a second circular pivot bending process, wherein the second pipe piece 18 bordering the first pipe piece 10 is bent outwards about a sharp angle or edge 20 about a right angle against the axial direction 16 . Thereby a conical flange is produced from the combination of the adjacent lying pipe pieces 10 and 12 , which are formed as a single piece on the pipe 12 .
[0035] The subsequent FIGS. 4 through 12 illustrate schematically the manner of operation of a device for carrying out the inventive process. In all figures for comparison purposes the same parts are indicated with the same reference numbers.
[0036] [0036]FIG. 4 shows a not-yet-clamped pipe 12 close to a clamping disk 22 in its not yet expanded resting state, which clamping disk 22 is rigidly connected to a drive shaft 24 which can be caused to rotate upon application of force. A first bending jaw 26 for bending the first pipe piece 10 about 150° into a position shown in FIG. 2 is represented in FIG. 4 in the starting position prior to the bending process, in partially broken away view. Therein it is to be noted that FIGS. 1 through 3, in comparison to FIGS. 4 through 12, are mirror images rotated 180° perpendicular to the pipe axis 28 . A second bending jaw 30 is rotated by 180° about the pipe axis 28 relative to the first bending jaw 26 shown likewise in its resting position prior to the bending process and shown partially broken away. The second bending jaw 30 serves for bending or introducing the angle into the second pipe piece 18 90° relative to the axial direction 16 of the position shown in FIG. 3. In FIG. 4 there are further shown a first shaping roller 32 and a second bending roller 34 likewise shown in their resting positions distanced from the pipe 12 . The first bending roller has a cross-section with rounded off tip 36 , of which the flanks 40 encompass an angle of 30°. Rotated by 180° about the pipe axis 28 is the second bend roller 34 provided removed from the pipe 12 into its resting position, of which the cross-section has a sharp angle 38 and of which the flanks 42 define a right angle. The shown condition of the device corresponds to the starting position of the process.
[0037] [0037]FIG. 5 shows a subsequent process stage, in which the clamping disk 22 is introduced into the pipe 12 and is extended to is spread position according to arrows 44 against the inner surface of the pipe 12 from the inside. Together with the clamping disk 22 , the bending jaws 26 and 30 are introduced into the pipe end, but are however both still in the rest position with respect to their pivoting for bending open the pipe end. Likewise, both shaping rollers 32 and 34 are still located in their rest position just as in FIG. 4. At the same time the drive shaft 24 is brought to rotate in the direction of arrow 46 , so that the clamping disk 22 rotates together with the pipe 12 , while the bending jaws 26 and 30 as well as shaping rollers 32 and 34 do not rotate about pipe axis 28 . The friction resistance between the cylindrical outer surface 48 of the clamping disk and the inner surface of the pipe 12 is so large, due to the clamping of the clamping disk 22 in its working position according to FIG. 5, that the pipe 12 rotates along with the clamping disk even overcoming large resistance.
[0038] The next process step of the shaping process is shown in FIG. 6, wherein the first shaping roller 32 is moved to its work position lying solidly against the outer side of the pipe 12 , having been moved along the displacement axis 52 according to arrow 50 .
[0039] According to FIG. 7, next the first bending jaw 26 is bent about an angle of 150° out of its resting position (FIG. 6) into its work position (FIG. 7), said pivoting about an axis perpendicular to the plane of the drawing, whereby the first pipe piece 10 projecting beyond the clamping disk 22 is bent outwards about 150° about the first shaping roller 32 . Since drive shaft 24 and clamping disk 22 rotate simultaneously together with the clamped pipe 12 about the rotation axis 28 , after only a few rotations of these parts about the pipe axis 28 the pipe piece 10 is bent outwards about 150° from the pipe 12 about the rounded off edge 14 . By the rotatable mounting of the shaping roller 32 the frictional resistance of the pipe piece 10 occurring at the location of bending is substantially reduced.
[0040] Subsequently, according to FIG. 8, the first shaping roller 32 is withdrawn along the displacement axis 52 , according to arrow 56 , out of the work position and back into its rest position away from the pipe 12 , and at the same time the first bending jaw 26 is pivoted back out of its work position according to arrow 58 , back into its rest position.
[0041] In the next processing step according to FIG. 9 the second shaping roller is moved out of its resting position along the displacement axis 60 according to arrow 62 into the working position in solid contact against the outer side of the pipe 12 . All of these process steps occur while the drive shaft 24 , the clamping disk 22 and the pipe 12 rotate about the rotation axis 28 and the first bending jaw 26 , second bending jaw 30 as well as the two shaping rollers 32 and 34 remain at rest. Preferably the rotating parts and the non-rotating parts are assembled respectively to stable work units. Within the non-rotating work tool unit, naturally the moveability of the individual parts to and from the rest position and the drive positions must be made possible. On the other hand, it is naturally also possible to allow the drive shaft 24 , clamping disk 22 and pipe 12 comprising work unit to remain at rest and the other work unit comprised of the bending jaws and the shaping rollers to rotate about the pipe axis 28 .
[0042] In the subsequent processing step according to FIG. 10 the second bending jaw 30 is pivoted according to arrow 64 out of its resting position into the working position, whereby the second pipe piece 18 projecting beyond the clamping disk 22 is bent outwards with a sharp bent angle 20 of 90° corresponding to the cross-section of the second shaping roller 34 . The complete bending of the second pipe piece 18 away from the pipe 12 towards outwards is accomplished after the rotating parts 24 , 22 and 12 have carried out a few rotations about the pipe axis 28 .
[0043] In the next processing step according to FIG. 11 the second shaping roller 34 is retracted from the pipe 12 along the displacement axis 60 according to arrow 66 and the second bending jaw 30 is pivoted back to its resting position along arrow 68 .
[0044] Therewith the path is cleared for the return movement of all parts back to the starting position as shown in FIG. 4. Thus, at the end of the process, all parts in accordance with FIG. 12 are again located in the starting position according to FIG. 4, and the result of the inventive work process is the one-piece or unitary forming onto the end of the pipe 12 a flange comprising the pipe segments 10 and 18 .
[0045] In FIGS. 13 through 16 a preferred embodiment of the device for carrying out the inventive process is shown schematically with the parts necessary for carrying out the invention. For improved overview, individual parts of the pieces are omitted, for example from the pipe 12 , the clamping disk 22 , the drive shaft 24 and the bending jaws 26 . It is further to be noted that in the illustrated device only one bending jaw 26 and shaping roller 32 is shown, which is suitable for a single bending process of a projecting pipe piece 10 . Obviously additional bending jaws and shaping rollers can be provided about the rotation axis 28 outside of the plane of the drawing. Their detailed description can however be omitted, since they function in the same manner as the parts shown in FIGS. 13 through 16. If an individual work unit comprised of bending jaw and shaping rollers is employed for each bent edge, then this has the advantage, that for the individual processing steps no work tools need be changed. It is necessary particularly in mass production that the processing units can come into engagement sequentially without interference.
[0046] Each of the work units including one bending jaw 26 and one shaping roller 32 is respectively mounted on a mobile sled 70 , wherein multiple sleds can be mounted radially on a base plate 72 . In this manner the individual processing units can be easily adapted to the respective diameters of the pipe 12 to be processed. Each sled 70 can be moved along two parallel sled guides 71 according to the double arrow 74 via a threaded spindle 78 rotated by a rotational drive 76 .
[0047] Two parallel side plates 80 (FIG. 16) are provided parallel and spaced apart from each other on the sled 70 , which are connected rigidly with each other in the manner of a frame by intermediate plates 82 . Between the two side plates 80 lying slidingly on the inner sides of the side plates 80 is a broad, somewhat circular or cylindrically shaped sector plate 84 , on which by means of screws 86 the bending jaws 26 are secured. The sector plate 84 forms, parallel to the side plates 80 , as can be seen in the cross-section of FIG. 13, an incomplete sector of a circle, of which the middle segment lying opposite the circular arc 88 is missing, since the center of the arc sector must remain free for the bending process of the pipe piece 10 . The angles 90 and 92 connecting to the outside of the circular arc 88 intersect outside the center point of the arc 88 . The bending jaws 26 are secured to the flat surface 92 of the sector plate 84 by screws 86 .
[0048] It is to be noted that in FIG. 16, in comparison to FIGS. 13 through 15, only those parts necessary for the pivoting of the bending jaws 26 is shown.
[0049] The guidance of the sector plate 84 during the necessary pivoting together with the bending jaws 26 occurs by guide rollers 94 , which run in arc-shaped guide grooves 96 in the side plates 80 . The guide rollers 94 project on both sides beyond the sides of the sector plate 84 and are respectively guided in a guide groove 96 . In the cylindrical circumference surface of the sector plate 84 corresponding to the arc 88 of the cross-section of the sector plate 84 there is provided gear teeth 98 , which are in engagement with a drive pinion 102 driven by rotational drive 100 . The sector plate 84 can therewith be pivoted out of the rest position of the bending jaws 26 according to FIGS. 13 and 14 into the work position of the bending jaws 26 corresponding to the position shown in FIG. 15. The pivot angle of the sector plate 84 can therein be freely widely selected and corresponds in the present case to the angle between the two flanks of the cross-section of the shaping roller 32 .
[0050] From FIGS. 13 through 15 it can further be seen, that the shaping roller 32 is mounted rotatable about its central axis 105 in a fork shaped mounting block 104 , which for its part is moveable along double arrow 50 , 56 out of its resting position according to FIG. 13 into the working position according to FIG. 14. For moving the mounting block 104 a threaded spindle 106 is provided driven by a drive motor 108 . It is important that the mounting block with shaping roller is secured in work position rigidly and capable of accepting high loads, according to FIGS. 14 and 15, with the working unit comprised of bending jaws, shaping rollers and associated parts.
[0051] In the work condition according FIGS. 13 through 15 the clamping disk 22 is introduced into the pipe end by movement of the pipe 12 , while it is still in its resting state as described above. Subsequently, the clamping disk 22 is, as described in greater detail below, spread to its work position and now cylindrically clamps pipe 12 from the inside. From this there results a pipe piece 10 projecting beyond the cylindrical outer surface of the clamping disk 22 , which is to be subsequently further bent in accordance with the following bending process. Prior to the sliding on of the pipe 12 upon the clamping disk 22 the working unit comprised of bending jaws, shaping roller and associated parts and drive mechanism is so adjusted by means of movement of the sled 70 along the double arrow 78 with respect to the fixed base plate 72 , that it is adapted to the respective diameter of the pipe 12 . In FIGS. 13 through 15 such a working unit is shown. Additional work units can be mounted on the base plate 72 with mostly doubled sled guides 71 radiating outward from pipe axis 28 , so that they can be sequentially brought to bear upon the pipe 12 , in order to respectively deform one pipe piece to a part of a complicated flange. For each sled 70 there is therein provided one rotation drive 76 with threaded spindle 78 , a threaded follower 110 running upon the threaded spindle 78 and a mounting means 112 connecting this with the sled 70 , wherein the mount 112 can be displaced in a slit 114 of the base plate 72 running radially to the pipe axis 28 .
[0052] In the following the design and manner of operation of a first embodiment of the clamping disk 22 is described in greater detail on the basis of FIGS. 17 through 20. Since the task of the clamping disk 22 is comprised therein, to prevent the deformation or change in form of the pipe inner side, it is important that a substantially complete contacting of the inner cylindrical circumference 116 of the pipe wall occurs. The shown preferred embodiment of the clamping disk is thus subdivided into multiple, in the illustrated embodiment six, sectors 118 , which in a subsequently in greater detail described manner can be spread from their inner rest position shown in the left half of FIGS. 17 and 18 into an outward work position in tensioned manner on the inside of the pipe 12 shown in the right half of FIGS. 17 and 18 via an axial drive, for example, a hydraulic cylinder 124 driven pull rod 122 . The number of the sectors is as large as desired. Therein a larger number of sectors has the advantage, that the gap 126 between the sectors 118 , which result following spreading of the clamping disk 22 , becomes smaller, and it covers the wall of the pipe 12 , even when the pipe is very thin walled, without changing the shape of the pipe. The sectors 118 are arc sectors and end, a distance from the pipe axis 28 , in a cylindrical-sectional inner surface 128 . The radial breadth of the sectors 118 can be freely selected, in order to conform the diameter of the clamp 22 to the respective diameters of the pipe 12 . The adaptation or conforming can occur by the simple exchange of sectors 118 . The inner surfaces 128 of sectors 118 lie on the cylindrical outer surfaces 130 of cylindrical shaped clamp jaws 132 . The sectors 118 are secured by radial screws 142 to the clamp jaws 132 . The clamp jaws 132 have a slanted inner face surface 134 with respect to the pipe axis 28 , which respectively lie against a face 136 of the widening end 120 of the pull rod 122 . In the illustrated embodiment the widening end 120 has a hexagonal cross-section, so that one side surface is provided for each of the six clamp jaws 132 .
[0053] The main drive shaft 24 for rotating the clamping disk and the pipe 12 is centrally axially bored through, and the pull rod 122 extends through this bore. By actuation of the hydraulic cylinder 124 the pull rod 122 can be moved from the rest position 138 shown in the lower half of FIG. 19 to the wider or working position 140 shown in the upper half of FIG. 19. Thereby the sectors 118 are moved out of the rest position shown in the left half of FIGS. 17 and 18 with close spacing from the inner surface of the pipe 12 into the working position shown in the right half of FIGS. 17 and 18 lying with tension against the inner surface of the pipe 12 . This movement is caused by the appropriate displacement of the clamp jaws 132 .
[0054] The drive shaft 24 extends through a cutout 144 of the base plate 72 of the overall device and is mounted rotatably in a manner known to those of ordinary skill and is caused to rotate by a drive motor 146 with hollow shaft drive 148 . The opposite end of the drive shaft 24 exhibits a mushroom shaped widening 150 with a planar end face 152 , upon which the planar slide surfaces 154 of the clamping jaws 132 lie radially slideable. The slide surfaces 156 of the clamp jaws lying opposite to the slide surface 154 lie slidingly against the inner surface of a counter slide 158 , which is secured by screws 160 to the mushroom shaped widening 150 . The screws 160 pass through the mentioned holes 169 in the clamp jaws 132 , which allow the necessary slight radial displacement of the clamp jaws 132 .
[0055] The screws 160 are surrounded by distance casing 162 , which together with the holes 169 of the clamp jaws 132 allows a linear radial guidance of the clamp jaws 132 .
[0056] The hydraulic cylinder 124 for operating the pull rod 122 is supported axially on the drive means 148 for the hollow drive shaft. The already sufficiently large force of the hydraulic cylinder 124 is again amplified as desired by the slanting of the widening end 120 of the pull rod 122 relative to the pipe axis 28 . In this manner the necessary amount of clamping force is produced, which produces a sufficient frictional connection of the clamping disk 22 to the pipe wall, in order to rotate the pipe against the resistance of the bending tools (bending jaws 26 and shaping roller 32 ). Of course, the slanting of the widening end 120 can be reversed, that is, be reduced towards the right in FIG. 19, in the case that an oppositely operated pressure rod is employed.
[0057] The return of the clamp jaws 132 during de-tensioning of the clamping disk 122 back into its rest position can occur in simple manner by not shown springs, which are incorporated in the individual clamp jaws, or by an endless pull-spring running about the outer circumference of the clamp jaws, likewise not shown, which would be incorporated in a likewise not shown groove.
[0058] Alternatively, the drive shaft 24 can, in the embodiment shown in FIG. 20, be mounted via a ball rotation ring 164 , of which the outer side (or even the inner side) is provided with gear teeth 166 . The drive motor 146 in this case is seated beside the ball rotation ring 164 . The pinion 168 of its drive shaft 170 engages in the teeth of the ball rotation ring 164 and brings about a driving of the drive shaft 24 . Naturally, other mounting types well know to those of ordinary skill can be considered.
[0059] An alternative advantageous embodiment of the clamping disk referred to in general with 22 and the drive therefore is shown in FIGS. 21 and 22. In this embodiment the clamping disk 22 exhibits clamp ring 174 with cylindrical circumference surface 116 and conical inner surface 176 , which clamp ring 174 is divided by a circumferentially running slanted slit 172 . Against the conical inner surface 176 lies the outer surface 178 of the clamp plate 180 having the same conical shape, which by means of bolts 182 and nuts 184 is secured to the widened end 186 of the pull rod 122 . By displacement of the pull rod 122 in the sense of the double arrow 188 between the detensioned resting position shown in the upper half of FIGS. 21 and 22 and the tensioned work position shown in the lower halves of FIGS. 21 and 22 the clamp ring 174 allows itself to be tensioned or as the case may be detensioned with development any desired amount of force. A slit of the clamping ring 174 running in the axial direction parallel to the pipe axis 128 would also be possible. The slanted arrangement of the slit 172 however prevents, that the gap opening during clamping causes a gap in the widening of the pipe wall causing a deformation or wrinkle in this location. The return of the clamp 174 during detensioning occurs in this case by the spring effect of the clamp ring itself. As necessary the spring effect can be amplified by a not shown circumscribing endless pull spring in a groove of the clamp ring 174 .
[0060] It is apparent that the sheet metal thickness of the pipe 12 , the desired flange shape, or a material change of the clamping disk 22 has no influence on the desired flange shape. The pipe end 10 , 18 is respectively slid so far over the clamping disk 22 , until sufficient material becomes available for the forming of the designed flange.
[0061] In the subsequent FIGS. 23 through 35 advantageous embodiments of bending jaws 26 and shaping rollers 32 are shown together with a segment of the pipe 12 to be deformed as well as a part of the spread clamping disk 22 . FIGS. 23 and 24 show a first embodiment of these parts, wherein in the above described manner the shaping rollers 32 are moved into a working position pressed against the outer side of the pipe 12 . The bending jaw 26 pivotable in the above described manner lies in its rest position against the inner side of the pipe piece 10 to be bent and extending beyond the clamping disk 22 , whereupon the pipe wall is clamped and held between the clamping disk 22 and shaping roller 32 . The tip 36 of the cross-section of the shaping roller 32 ends at the point, where the projecting pipe piece 10 is to be bent. By the shape of the shaping roller 32 the shape of the bending edge on the pipe end can be determined.
[0062] The pivotable bending jaw 26 lies on its resting position according to FIG. 23 against the inner side of the pipe piece 10 . Its axial breadth is at least somewhat larger than the axial length of the pipe piece 10 to be bent. Thereby it is ensured that the pipe piece to be bent is lifted as a whole and thus is not changed in its linear shape. Likewise the cylindrical contact surface 190 of the bending jaw 26 should have the same radius at the pipe end as the pipe inner side, so that the pipe piece 10 to be bent has a large surface area contact surface.
[0063] Since the pivotable bending jaw 26 can only bend a partial area of the pipe circumference, the pipe 12 must be caused to rotate in an even, slow rotation. If the pipe 12 rotates, then the bending jaw 26 is pivoted slowly to the desired bending angle (FIG. 24). The bending jaw 26 remains in this work position until the end of its last complete rotation of the pipe 12 about the pipe axis 28 , whereupon the bending out of the pipe piece 10 is ended.
[0064] So that the pipe 12 following the forming of the flange or rim can be removed from the clamping disk 22 , the shaping roller 32 with its mounting lock 104 must be withdrawn to a rest position sufficiently far from the pipe. For a further circular bending process now a further processing unit, which is adjusted to a further bending angle, is brought to action in the above-described manner.
[0065] For the easier introduction of the clamping disk 22 into the pipe end 10 the introduction side of its cylindrical outer surface 48 can exhibit a conical narrowing 192 .
[0066] In FIGS. 25 through 28 various embodiments of the shaping roller 32 or, as the case may be, 34 are shown with narrow tip 36 or, as the case may be, right-angled tip 38 . The tip 36 serves for bending of the pipe piece 10 about 1500, while the tip 38 serves for bending the pipe piece 10 about 90°.
[0067] In FIG. 29 there is schematically shown how, absent precise demands on the forming precision of the formed flange or rim, one can entirely bend without shaping rollers and only with clamping disk 22 and bending jaws 26 .
[0068] [0068]FIGS. 30 and 31 show an embodiment of the bending jaw 26 with almost half cylindrical contact surface 190 in resting position (FIG. 30) and work position (FIG. 31).
[0069] [0069]FIG. 32 shows in somewhat enlarged scale a partial representation of a somewhat differently shaped bending jaw 26 with flatter cylindrical contact surface 190 , which is secured by screws 86 to a only partially shown, pivotable sector plate 84 . The contact surface 190 lies with all its frictional force against the inner wall of the not shown pipe. In the following figures the individual advantageous embodiments of a similar bending jaw 26 as in FIG. 32, however with less friction between contact surface 190 and pipe inner wall is shown. It is actually ideal, when the working radius of the contact surface 190 of the bending jaw 26 corresponds to the pipe inner diameter. Without serious disadvantage the radius of the contact surface 190 can however be smaller than the pipe inner radius. Thereby it is possible, with the same bending jaws to change through multiple pipe diameters. In the main friction location in the center of the contact surface 190 there can, for a substantial reduction of friction and drive, in the body of the bending jaw 26 a roller mounted support roller 194 be introduced, of which the rotation axis 196 runs parallel to the contact surface 190 and of which the circumference surface 198 projects slightly beyond the contact surface 190 . The pipe piece 10 to be bent then lies in this area free of friction on the circumference surface 198 of the support roller 194 .
[0070] The bending jaws 26 can be further improved by introduction of a whole series or chain of support rollers 194 in the contact surface 190 in the same manner as the support roller 194 according to FIG. 34. In the shown embodiment according to FIG. 34 five such support rollers 194 are provided in a chain. The remaining part of the contact surface 190 between the support rollers 194 prevents a drooping of the wall of the pipe 12 between the support rollers 194 which would result in wave formation and stretching or distortion.
[0071] A minimal friction between bending jaws 26 and the inner wall of the pipe 12 is achieved when the bending jaws 26 according to FIG. 35 are fully cylindrical with cylindrical contact surfaces 190 , wherein the entire cylindrical bending jaws 26 are mounted rotatable about a drive shaft 200 on the sector plate 84 . Although in this manner the least amount of friction is produced, since however in most cases insufficient space is available for a large diameter of the cylindrical shaped bending jaws 26 , one must accept the disadvantages in the deformation formation as well as stretching of the pipe wall. These disadvantages are lesser in the case of greater pipe wall thicknesses so that in the case of bending thicknesses above 1.5 mm such a “bending roller” can be employed in the place of bending jaw 26 .
[0072] The total inventive device for carrying out of the inventive circular pivot bending process can selectively be carried out both in the horizontal as well as in the vertical pipe axis 28 , wherein there is preferred on the one hand straight pipes and on the other hand shorter pipe-shaped pieces to be shaped.
[0073] For a rational preparation of straight pipes with flanges 10 , 18 formed on both ends using the inventive circular bending process, devices 204 of the described type are seated upon a common rail system designated overall with 202 mounted to be slidable according to the double arrow 206 , so that the clamping disk 22 and bending jaws 26 indicated schematically lie on opposite ends. Each device 204 can be moved using an independent driven threaded spindle 208 in the rail system 202 .
[0074] For introduction of the pipe 12 the devices 204 are moved apart from each other, until the pipe length of the pipe 12 fits between the clamping disk 22 . After that both devices 204 are moved towards each other, the clamping disks 22 are introduced into the pipe ends until reaching an abutment, which is set to the processing length of the pipe. Both clamping disks 22 are clamped in the processing position, and processing occurs subsequently simultaneously on both sides. For removal of the pipe 12 the devices 204 must again be moved apart from each other.
Reference Number List 10 first projecting pipe piece 12 pipe 14 bending edge 16 axial direction of the pipe 18 second projecting pipe piece 20 sharp bending edge 22 clamping disk 24 drive shaft 26 first bending jaw 28 pipe axis 30 second bending jaw 32 first shaping roller 34 second shaping roller 36 tip of first shaping roller 38 tip of second shaping roller 40 flanks, first shaping roller 42 flanks, second shaping roller 44 arrow showing spreading direction 46 arrow, drive shaft 48 outer surface 50 arrow 52 displacement axis 54 arrow 56 arrow 58 arrow 60 displacement axis 62 arrow 64 arrow 66 arrow 68 arrow 70 sled 71 sled guide 72 base plate 74 double arrow 76 rotation drive 78 threaded spindle 80 side plate 82 intermediate plates 84 sector plate 86 screws 88 arc 90 straight 92 straight 94 guide rollers 96 guide rollers 98 gears 100 rotation drive 102 drive pinion 104 mounting block 105 central axis 106 threaded spindle 108 drive motor 110 spindle follower 112 holder 114 slit 116 circumference 118 sector 120 widening end 122 pull rod 124 hydraulic cylinder 126 gap 128 inner surface 130 outer surface 132 clamp jaws 134 end face 136 end face 138 rest position 140 work position 142 screw 144 segment 146 drive motor 148 hollow shaft internal gear 150 widening 152 end face 154 slide surface 156 slide surface 158 counter disk 160 screws 162 distance housing 164 ball rotation mount 166 gear 168 pinion 169 holds 170 drive shaft 172 slit 174 clamping ring 176 inner surface 178 outer surface 180 clamping plate 182 bolt 184 nut 186 connecting end 188 double arrow 190 contact surface 192 slanting 194 support roller 196 rotation axis 198 circumference 200 drive shaft 202 rail system 204 circular rivet bending device 206 double arrow 208 threaded spindle
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The invention relates to a method and device for forming a one-piece flange ( 10, 18 ) or rim on the end of a steel or sheet-metal ( 12 ) pipe. The pipe is placed in a flat position on all sides on the inner surface thereof close to the end thereof and is clamped. One part of the pipe ( 10 ) protrudes above the clamped section of the tube ( 12 ). The protruding part of the pipe is bent by applying surface pressure against a peripheral section on the inner surface thereof, until a desired outward flectional angle is obtained. The desired flectional angle on all parts of the pipe ( 10, 18 ) or a part or section ( 10 ) thereof is gradually achieved by rotating the pipe ( 12 ) relative to the peripheral section wherein the flexing occurs.
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FIELD OF THE INVENTION
This invention relates to the field of multiple pane insulating windows, and, in particular relates to an improved flexible corner connector piece for joining adjacent spacer elements which are used to separate the panes of a multiple pane window.
BACKGROUND OF THE INVENTION
Insulating glass panes of the type commonly used as glazing in windows and doors are normally constructed by sandwiching a spacer frame assembly between sheets of glass, and thereafter bonding the sheets to the spacer frame assembly to form an air-tight seal. While, in the past, finished panels were typically square or rectangular, there has been substantial growth in popularity of finished panels having rounded or radiused corners, rather than sharp angles.
It is well known in the art to provide spacer frame assemblies between sheets of glass which consist of several relatively rigid and usually straight spacer tubes, interconnected by a plurality of corner pieces or corner keys. Typical corner keys are disclosed, for example, in U.S. Pat. No. 2,989,788, issued to Kessler; U.S. Pat. No. 4,530,195, issued to Leopold; and U.S. Pat. No. 4,822,205, issued to Berdan. Such keys may be rigid (Mulligan and Kessler), or flexible (Leopold, Berdan). Flexible keys are typically manufactured from appropriately flexible thermoplastics, and may be provided with a locking or positioning mechanism to insure the creation of a precise angle. See, for example, Leopold, or U.S. Pat. No. 5,048,997, issued to Peterson.
Heretofore, however, flexible corner keys, such as those taught by Leopold and Peterson, have been unacceptable in many installations, insofar as they tend to create a relatively sharp corner.
Along with the growth and popularity of finished panels having rounded or radiused corners, there have been an increased need for corner keys suitably, adapted to the useful and aesthetically pleasing large radiuses.
SUMMARY OF THE INVENTION
The present invention provides a flexible corner piece for use in the construction of a spacer frame for insulated glass panels which overcomes the above problems. Specifically, the flexible corner piece is provided with opposing end sections suitable for mating with spacer tubes. In addition, the flexible corner piece of the present invention has a variably flexible center section having a smooth and contiguous outer face, opposing a parallel, serrated face provided with suitable serrations thereby allowing the corner piece to flex along a variable radius.
DETAILED DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a corner piece according to the present invention.
FIG. 2 is a perspective view of a glass panel assembly incorporating a spacing assembly utilizing corner pieces according to the present invention and describing the spacer assembly of the present invention.
FIG. 3A is a cross-sectional view of the interface between the spacer tube and corner piece of the present invention.
FIG. 3B is a perspective assembly view of the elements of FIG. 3A depicted separately.
FIG. 4 is a plan view of the corner piece according to the present invention shown with a single simple radiused curvature, with detail shown at FIG. 4A.
FIG. 5 is a plan view of the corner piece of the present invention showing a compound curve.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The invention can best be understood by initially referring to FIG. 1, which shows a corner piece 10 having the following attributes:
Corner piece 10 is provided with opposing ends sections 12A and 12B having relieved portions 13. Affixed to longitudinal elements 15 of end portions 12, are tabs 22 which protrude perpendicular to inner surface 17. The corner piece 10 has a center section 14, in turn having a contiguous, uninterrupted surface 16 which is perpendicular to front and rear sides 19A and 19B. Opposite surface 16 is opposing surface 18, which is interrupted by a plurality of serrations 20 which are interspersed along the length of center portion 14. Serrations 20 are in the form of slots having substantial depth, thereby imparting flexibility to corner piece 10.
As shown in FIG. 2, a plurality of corner pieces 10 serve to interconnect a plurality of spacer tubes 30 to form a spacer assembly which is placed between panes of glass 32A and 32B, thereby creating an air space. A sealant (not shown) is applied to the spacer assembly consisting of spacer tubes 30 and corner pieces 10 prior to assembly of glass panes 32A and 32B, trapping a volume of air between glass panes 32A and 32B and the spacer assembly. In the preferred embodiment, a dessicant (not shown) is applied to the inner surface of the spacer assembly, attracting and binding any water molecules in the air space between panes 32A and 32B to prevent fogging of the glass.
Referring now to FIGS. 3A and 3B, the interface between the corner piece 10 and spacer tube 30 can be better understood. In the preferred embodiment, inserted end section 12 of corner piece 14 is inserted into an open end of spacer tube 30, which is preferably, but not necessarily, rectangular in cross-section. Tabs 22 are formed or affixed on end 12. The dimension of the thickness of the longitudinal extension 15 and the length of tab 22 selected to insure that the dimension H shown in FIG. 3A is slightly greater than the corresponding inside dimension of the tube 30. In this fashion, insertion of end 12 into the open end of tube 30 results in a frictional fit of end section 12 inside to remain in fixed engagement with the interior of tube 30. In the preferred embodiment, center section 14 has a height and width substantially similar to the external height and width of the tube 30. End sections 12, however, have an overall height and width which corresponds to the internal height and width of tube 30. These dimensional differences between body 14 and end sections 12 creates a shoulder portion 21 which abuts the end surfaces 31 of tube 30 when corner piece 10 is fully inserted into tube 30.
Referring now to FIG. 4, the importance of serrations 20 will be best understood. Serrations 20 are preferably formed as slots in body 14, by removal of small portions of body portion 14 by virtue of molding techniques, cutting, sawing or other well known processes. These slots can be appreciated in detail as shown in FIG. 4A. By virtue of the empty spaces existing as a result of this slotting, the body portion 14 of corner piece 10 may easily be flexed. By selecting material for the corner piece 10 from the appropriate, class of thermoplastics, a flexible, resilient, deformable corner piece is achieved. Additionally, by regulating the number, position, width and depth of slots 20 in relation to body 14, varying degrees of flexibility and radius of curvature may be pre-determined.
In addition, as shown in FIG. 5, the corner piece 10 of the present invention is likewise capable of compound curvature. As shown in FIG. 5, the body 14 of corner piece 10 may be flexed so as to both compress and to distend slots 20 to create multiple radiuses (e.g., r2 and r3).
In the preferred embodiment, a plurality of corner pieces 10 are inserted to act as corner points in glass assemblies 28. By virtue of their flexibility, a single corner piece 10 may be formed into a wide variety of different radiuses, limited only by the amount of material removed from the total number of slots 20 found on the body 14. Further, when flexed, the corner piece presents a smooth and attractive contiguous exterior surface 16, and two substantially parallel support surfaces 19A and 19B for supporting opposing plates of glass.
Having thus described my invention in detail, numerous obvious improvements and modifications thereto may be made without departing from the essence of my invention, which I claim as follows:
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The invention is a flexible corner piece for use in the construction of a spacer frame for insulated glass panels. The corner piece is provided with opposing end sections suitable for mating with spacer tubes. In addition, the flexible corner piece has a variably flexible center section having a smooth and contiguous outer face opposing a parallel serrated face, thereby allowing the corner piece to flex along a variable radius.
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FIELD OF INVENTION
[0001] The present invention relates to monoclonal antibodies that recognize the M2-1 protein of human respiratory syncytial virus (RSV), useful for development of diagnostic methods for RSV infection and production of pharmaceutical compositions for the treatment and/or prophylaxis of RSV infection.
BACKGROUND OF THE INVENTION
[0002] Acute respiratory tract infections are the major cause of pediatric hospitalizations and deaths worldwide (Bryce, Boschi-Pinto et al. 2005). During the cold months, respiratory tract infections caused by viruses are exacerbated and produce an increased number of cases, a situation that acquires the features of an outbreak. The viruses causing these epidemics in the pediatric population are mainly respiratory syncytial virus (RSV), adenovirus (ADV) and influenza virus. Another causative agent of respiratory tract infections is metapneumovirus (hMPV), a recently identified virus and which causes severe respiratory infections in children under two years of age (van den Hoogen, Herfst et al. 2004), although its diagnosis is not widespread. However, RSV is the major causative agent of acute respiratory tract infections in infants worldwide, causing severe outbreaks in winter months. According to WHO, the virus infects 64 million people annually, of which 160,000 die (www.who.int). Infection by this virus causes a wide range of clinical conditions, which may be mild such as rhinitis or more severe, such as pneumonias or bronchiolitis; the most severe diseases are seen in infants, preterm, children with congenital heart diseases and in immunocompromised children (Cabalka 2004). In addition, the infection caused by this virus is extremely common and recurrent, since almost 100% of children over three years have presented at least one episode of RSV infection (Bont, Versteegh et al. 2002). Since this infection does not leave adequate immunological memory reinfections are frequent, declining its severity with increasing patient age. However, reinfected individuals act as reservoirs and are a source of infection for infants younger than 1 year of age, those who develop severe respiratory symptoms. In Chile, during the cold months (May-August) this virus is the cause of 70% of acute lower respiratory tract infections requiring hospitalization (Avendano, Palomino et al. 2003), being the cause of the death of 0.1% of them. Although this percentage is low, the large number of cases makes the number of deaths very significant. This situation causes the saturation of emergency healthcare services, which often has made necessary the implementation of emergency measures in health services, including the conversion of hospital beds for pediatric patients, suspension of elective and scheduled surgeries and recruitment of supporting staff during the months when the outbreak occurs. The RSV diagnostic method often used in hospital facilities is a diagnostic test based on the detection of viral antigens by direct immunofluorescence of nasopharyngeal swabs. The limitation of this test is related to the need of having trained personnel for processing and analysis of samples and, besides, the results of said test are not immediately acquire, leaving a period of time within which the patient remains undiagnosed, but the infection continues its course. Due to this problem, the development of efficient monoclonal antibodies, which can be used for creating alternative detection test for RSV requiring minimum training and being fast to perform (as, e.g., immunochromatographic test), appear as necessary alternative to meet this need, since they allow the specific recognition of viral antigens in samples from patients infected with RSV, and also requiring a small amount of sample. Thus, our invention results in an antibody capable to detect low amounts of RSV antigens very efficiently and effectively, allowing the development of a fast, efficient and accurate alternative detection and diagnostic method for patients infected with RSV, in order to establish an appropriate and early treatment having effect in the development of the disease. Furthermore, the efficiency of our antibody allows us to suggest their use for the preparation of pharmaceutical compositions for treatment and/or prophylaxis of RSV infection. The antibody of the invention is specifically a monoclonal antibody recognizing M2-1 protein of human RSV and which is secreted by 8A4/G9 hybridoma.
SUMMARY OF THE INVENTION
[0003] The present invention relates to the use of monoclonal antibodies specific for respiratory syncytial virus (RSV). Specifically, the invention relates to a monoclonal antibody IgG2A secreted by the cell line of 8A4/G9 hybridoma specifically directed to the M2-1 viral antigen, which is associated with the nucleocapside of the virus. The antibodies can be used for assays for the detection and/or determination of RSV infection. Said antibodies are in the pure state and do not contain any other contaminating biological material. In the description of the antibody of the invention are used indistinctly the terms M2-1 protein and M2 protein.
[0004] In another aspect of the invention a method for preventing and treating the infection caused by respiratory syncytial virus (RSV) in a given host is provided, comprising the administration of a composition containing the monoclonal antibodies secreted by the 8A4/G9 hybridoma in sufficient doses to prevent the disease. The antibody can be humanized in order to minimize the possibility of an immune response against the same in the patient.
[0005] In addition, the invention can be used to obtain any pharmaceutical form of the formulation of the monoclonal antibodies secreted by the 8A4/G9 hybridoma, which are suitable for the treatment or prevention of the disease caused by RSV.
[0006] The invention also provides methods for detection and diagnosis of RSV viral antigens in biological samples using the monoclonal antibodies produced and secreted by cells of the 8A4/G9 hybridoma by assays such as ELISA, immunofluorescence microscopy, immunohistochemistry, flow cytometry, cell purification (CellSorter, by fluorescence, by association to magnetic beads or any other separation method using the antibody), immunoprecipitation, Western blot and chromatography. Samples may be in vitro cells infected with RSV or samples obtained from individuals suspected of RSV infection. In the case of a person samples, they may be nasal secretions, nasal irrigations, pharyngeal secretions, bronchial secretions or washings or any other appropriate type of sample. The invention provides the opportunity to develop a method for isolation and detection of respiratory syncytial virus in biological samples and cell cultures by contacting them with the monoclonal antibodies produced and/or secreted by the cell lines of 8A4/G9 hybridoma coupled to any type of solid support, as, e.g., nitrocellulose, nylon membrane or another support. The invention provides the opportunity for developing kits for rapid detection of Respiratory Syncytial Virus or the like, containing antibodies produced by 8A4/G9 hybridoma. It also provides the possibility of incorporating any kind of molecule or substrate chemically bound to the monoclonal antibodies secreted by the 8A4/G9 hybridoma, such as fluorophores, biotin, radioisotopes, metals, enzymes and/or any chemical element coupled to the monoclonal antibodies secreted by the 8A4/G9 hybridoma, as screening, treatment, analysis and/or diagnostic method in biological samples.
DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 : Nucleotide sequences and amino acid sequences deduced from the variable regions of the light and heavy chains of immunoglobulin G secreted by the 8A4/G9 hybridoma A. Nucleotide sequence of the messenger RNA encoding the heavy chain (IgGVH-8A4/G9, upper panel) and light chain (IgκV L -8A4/G9, lower panel), obtained by sequencing the complementary DNA prepared from a sample of total RNA purified from the actively growing hybridoma B. Deduce amino acid sequence for the variable region of the heavy chain (IgGVH-8A4/G9, upper panel) and light chain (IgκV L -8A4/G9, lower panel).
[0008] FIG. 2 : Graph showing detection test results for the M2 antigen of RSV by ELISA, using the anti-M2 antibody of 8A4/G9 clone (first bar), polyclonal anti-M2 antibodies produced in rabbit (second bar), secondary anti-mouse IgG-HRP antibody only (third bar), the secondary anti-rabbit IgG-HRP antibody (fourth bar), anti-M2 antibody of 8A4/G9 clone but with no presence of antigen (fifth bar) and polyclonal anti-M2 antibodies produced in rabbit but with no presence of antigen (sixth bar). It can be seen that monoclonal anti-M2 antibody from 8A4/G9 clone detects more efficiently the M2 antigen than the polyclonal antibody produced in rabbit.
[0009] FIG. 3 : Graph representing the result obtained from a performance test of the monoclonal anti-RSV M2 antibody of 8A4/G9 clone for detecting the antigen at different antibody dilutions and determining its specificity. The monoclonal anti-M2 antibody (425 μg/ml) was used at 1/100 dilution (4.25 mg/ml final concentration) (first bar), 1/1,000 dilution (425 ng/ml final concentration) (second bar), 1/2,000 dilution (212.5 ng/ml final concentration) (third bar), and also as negative control was used hMPV M2 protein as antigen (fourth bar), secondary anti-mouse IgG-HRP antibody alone (fifth bar) and control with no antigen (sixth bar).
[0010] FIG. 4 : Graphs showing the sensitivity results of monoclonal anti-M2 antibody at 1 in 100 dilution (4.25 ug/ml) ( FIG. 4A ) and at 1 in 1,000 dilution (425 ng/ml) ( FIG. 4B ). Each graph shows the antibody ability to detect the antigen in different amounts. The amounts of antigen tested were 1 ug (first bar), 500 ng (second bar), 100 ng (third bar), 50 ng (fourth bar), 25 ng (fifth bar), control with no antigen (sixth bar), specificity control in which adenovirus P8 protein is used as antigen (seventh bar) and a secondary anti-mouse IgG-HRP antibody (eighth bar).
[0011] FIG. 5 : Graphs showing data detection of RSV infected HEp-2 cells with monoclonal anti-M2 antibody (425 μg/ml), at a dilution of 1 in 3,000 (141.6 ng/ml) ( FIG. 5A ) and at a dilution of 1 in 7,500 (56.6 ng/ml) ( FIG. 5B ) by flow cytometry. Each graph shows the antigen detection in infected cells (black bars) and uninfected cells (open bars), using the monoclonal anti-M2 antibody (first pair of bars), a control with only the secondary anti-mouse IgG-FITC antibody (second pair of bars) and a positive control with an anti-RSV F antibody (Bourgeois, Corvaisier et al. 1991) ((third pair of bars). This latter antibody was used at a dilution of 1 in 1,000 in both assays.
[0012] FIG. 6 : FIG. 6A shows immunofluorescence images of HEp-2 cells infected and stained with monoclonal anti-M2 antibody of the invention. FIG. 6B shows the immunofluorescence images of HEp-2 cells infected and stained with monoclonal anti-F antibody from Millipore. In the images, the upper left shows an image of the staining only in the green channel, corresponding to the label for RSV M2, the upper right image shows staining only in the blue channel corresponding to the nuclear label and the bottom image shows the two channels together.
[0013] FIG. 7 : Graphs showing the results of determination of RSV by ELISA assay for commercial anti-F antibody ( FIG. 7A ) and for the monoclonal anti-M2-1 antibody ( FIG. 7B ). Each graph shows the ability of the antibody to detect the antigen (first bar), a control with no antigen (second bar) and a control in which only a secondary antibody is used (third band). FIG. 7C corresponds to a graph showing the results of both antibodies. They show that the monoclonal anti-M2-1 antibody is able to better detect virus particles than the commercial anti-F antibody.
[0014] FIG. 8 : Graphs representing the results of determination of RSV by ELISA assay for monoclonal anti-M2-1 antibody diluted 1 in 100 (4.25 ug/ml) ( FIG. 8A ), for the commercial anti-F antibody diluted 1 in 100 (10 μg/ml) ( FIG. 8B ) and for anti-RSV-DHI antibody diluted 1 in 10 ( FIG. 8C ). Each graph shows the ability of the antibody to detect the antigen (first bar), a control with no antigen (second bar) and a control in which only a secondary antibody (third band) is used. The graph of FIG. 8D shows the results of the three antibodies. It is observed that our monoclonal antibody was the only one able to recognize viral particles.
[0015] FIG. 9 : Graphs showing the results obtained by sandwich ELISA using the monoclonal anti-M2 antibody of the invention, and using samples of nasopharyngeal swabs of patients previously diagnosed with or without RSV infection. Three patients positive for RSV ( FIGS. 9A , 9 B and 9 C), one patient positive for hMPV ( FIG. 9D ), a healthy patient ( FIG. 9E ) and negative controls with no sample and with no capture antibody to determine the specifying signal ( FIG. 9F ) are shown. In FIGS. 9A to 9E , the first bar of the graphs represents the viral antigen detection using the detection antibody (polyclonal antibody) at a dilution of 1 in 1,000; the second bar represents the viral antigen detection using the detection antibody at a dilution of 1 in 2,000; the third bar corresponds to a control in which has not been used detection antibody; and the fourth and fifth bar shows the result of the assay performed without activation of the plate with monoclonal antibody, but using detection antibody in dilutions of 1 in 1,000 and 1 in 2,000, respectively. FIG. 9F shows a graph corresponding to controls, where the first two bars show the result of the test with no sample, at two dilutions of the detection antibody (1 in 1,000 and 1 in 2,000), and the third and fourth bar shows the result of the assay with no sample and with no capture antibody and with two dilutions of the detection antibody (1 in 1,000 and 1 in 2,000).
DETAILED DESCRIPTION OF THE INVENTION
[0016] The present invention relates to the ability of monoclonal IgG2a antibody for the specific recognition of an antigen derived from the M2-1 protein, which is associated with the Respiratory Syncytial Virus (RSV) nucleocapsid.
[0017] A monoclonal antibody is a type of homogeneous antibody characterized by being able of recognize specifically a single antigen. They are produced by a single hybrid cell (hybridoma), which is the product of the fusion B lymphocyte clone and tumoral plasma cell. The property of binding specifically and with high affinity to an antigen has promoted the development of monoclonal antibodies as a useful tool for detection of molecules that generate a great scientific, clinical and industrial interest. At present, monoclonal antibodies are widely used in both basic and applied research, because of their specificity and reproducibility, which allows for better substantiated research. However, it is in the area of biomedicine where monoclonal antibodies have had enormous practical applications, either for diagnosis and treatment of many infectious diseases, and as therapy for other diseases. Although monoclonal antibodies are used in all kinds of techniques for detection and diagnosis, is in the design of in vitro diagnostic kits where have been obtained the best results. For this, there are currently several rapid detection kits, such as pregnancy tests, based on the determination of human chorionic gonadotropin (hCG) levels in urine using anti-hCG antibody. Furthermore, monoclonal antibodies for therapeutic use have become really important. Currently there are therapeutic treatments for various diseases using commercial monoclonal antibodies as Alemtuzumad, Gemtuzumab ozogamicin, Rituximab, Trastumab etc. (Reichert).
[0018] RSV is an enveloped RNA virus belonging to the Paramyxoviridae family, subfamily Pneumovirinae. Its RNA is transcribed into 10 mRNA, each one of which encodes a viral protein, except for the M2 mRNA, which has two open reading frames (ORF) overlapped in 22 nucleotides encoding two different proteins: ORF-1 encoding M2-1 and ORF-2 encoding M2-2. The proteins encoded by other mRNAs are the nucleoprotein (N), phosphoprotein (P), L protein, matrix protein (M), NS1, NS2, SH, fusion protein (F) and G. N protein is associated with the genomic RNA to form the nucleocapsid, L is an RNA polymerase associated with the nucleocapsid, P interacts with N and L, M is a non-glycosylated protein that is located on the inner side of the viral envelope, NS1 and NS2 are nonstructural proteins, and SH, G and F are part of the viral envelope. RSV diagnostic kits developed until now use antibodies against F, N and/or G proteins of RSV, and the antibodies suggested for the treatment or prophylaxis of RSV infection are also directed to the same proteins (CL948-96, CN101130765, U.S. Pat. No. 6,790,611, WO2009088159, (Erdman and Anderson 1990), (Murray, Loney et al. 2001)). Currently, there are no RSV diagnostic kits or pharmaceutical compositions for treatment and/or prophylaxis of RSV infection using antibodies that bind to the RSV M2-1 protein.
[0019] M2-1 is a polypeptide with a molecular weight of 22 kD that functions as a transcriptional factor, which prevents premature termination during transcription and, thus, facilitates transcriptional reading at the junction of genes and allows access of RSV polymerase to downstream transcriptional units. This process occurs throughout the replication cycle of RSV, where the M2-1 protein, newly synthesized, is associated to the nucleocapsid through its interaction with P. In addition, it was observed that the M protein is associated to the nucleocapsid only in presence of M2-1, and has been suggested that this interaction allows to shutdown virus transcriptase activity, presumably to start the assembly and budding by interacting with the envelope glycoproteins (Li, Jans et al. 2008). In the present description the terms M2-1 protein and M2 protein are used interchangeably.
[0020] From our research related to the effects of viral antigens derived from Respiratory Syncytial Virus (RSV) on the immune system, we have generated murine monoclonal antibodies specific for detecting RSV antigens that have advantages over commercially available antigens. Specifically, the monoclonal antibody produced by 8A4/G9 hybridoma proved to be very useful for determining RSV infection by in vitro and in vivo immunological assays using various detection techniques. Because of this, these antibodies allow to have a valuable tool for detection, diagnosis and/or therapy of infection caused by Respiratory Syncytial Virus in any biological sample where is present a low viral load. This monoclonal antibody may have many therapeutic and diagnostic applications, such as use in immunoblot techniques, immunofluorescence, immunochromatography, flow cytometry, production of pharmaceutical forms that comprise the same, or any other application involving their use. The antibody can be bound to a label that allows its detection. Examples of possible labels correspond to fluorophores, biotin, radioisotopes, metals, enzymes and any other suitable label for antibodies.
[0021] The monoclonal antibody of the invention can be found in its natural form as secreted by the hybridoma, or alternatively as antigen binding fragments. The antigen binding fragments are antibody fragments able of binding to antigen, such as Fab or Fab′ fragments. In the present application, the applications of the antibody of the invention, although mention the use of the antibody, also include the use of binding fragments of monoclonal anti-M2 antibody. Furthermore, in the case of the generation of compositions comprising the antibody of the invention, such compositions may comprise the murine antibody or the humanized or chimeric antibody of the invention. This is especially useful in compositions for human administration and as a way to minimize the possibility that the immune system of the individual treated with the composition could generate a response against the antibodies of the invention.
[0022] Examples demonstrating the different applications of the monoclonal antibody of the invention are described below.
EXAMPLE 1
Determination of the Nucleotide Sequence Encoding the Variable Region Light Chain (VL) and Variable Region Heavy Chain (VH) of the Anti M2-1 Immunoglobulin Secreted by the 8A4/G9 Hybridoma
[0023] 8A4/G9 hybridoma was grown in DMEM-highglucose medium from GIBCO-BRL (Invitrogen, Cat. No.: SH30243.01) supplemented with 3.7 g/L sodium bicarbonate and 10% fetal bovine serum (HyClone) at 37° C. with 10% CO 2. When the cell density reached 700,000 cells/ml, 3.5×10 6 cells were recovered and from these cells a purification of total RNA was performed using Trizol (Invitrogen, Cat No.: 15596-018), as previously described (Chomczynski 1993). 0.5 μg of RNA was retrotranscribed to complementary DNA using the Impron II kit from Promega and 2 μl of the reaction were used to perform a polymerase chain reaction (PCR) using primers supplied in the Ig-Primer set Kit from Novagen (Cat No.: 69831-3) following to suppliers instructions, in a Axygen MaxyGene™ Thermal Cycler. PCR products were obtained with the primers whose sequences are: For the heavy chain MuIgVH5′-A: 5′GGGAATTCATGRASTTSKGGYTMARCTKGRTTT3′ and MuIgVH5′-F: 5′ACTAGTCGACATGAACTTYGGGYTSAGMTTGRTTT3′; for the light chain MuIgκV L 5′-B: 5′GGGAATTCATGGAGACAGACACACTCCTGCTAT 3′ and MuIgκV L 5′-C: 5′ACTAGTCGACATGGAGWCAGACACACTSCTGYTATGGGT3′. PCR products were cloned into the pCr TOPO-TA cloning vector (Invitrogen, Cat No.: K450001SC), following the suppliers instructions, and sequenced by the sequencing service of the Pontificia Universidad Católica de Chile in a Ablprism 3130xl Genetic Analyser (Applied Biosystem). The DNA sequence obtained is shown in FIG. 1A and the deduced amino acid sequence is shown in FIG. 1B . The amino acid sequence was obtained using the bioinformatic software Vector NTI (Invitrogen).
EXAMPLE 2
Detection Assay for RSV Antigens, Specificity of Monoclonal M2-1 Antibody for Purified RSV Antigens
[0024] The objective of this assay is to demonstrate the specificity of our antibody for RSV viral antigens. The antigen detection was carried out by direct ELISA technique, where the ELISA plate was activated with 200 ng of purified antigen for 10 hours at 4° C. After that the plate was washed once with 1× PBS/0.02% Tween, and twice with 1× PBS, and the plate was then blocked for 2 hours with 1× PBS/3% BSA at room temperature. The washes were repeated and the plate was then incubated with anti-VRS M2 antibody of 8A4/G9 clone (425 μg/ml) at a dilution of 1 in 100 in 1× BS/1% BSA for 2 hours at room temperature. Washes were repeated after the completion of the incubation time and the plate was incubated with an anti-mouse IgG antibody labeled with horseradish peroxidase enzyme (Horseradish peroxidase, HRP) at a dilution of 1 in 2,000 in 1× PBS/1% BSA for 1 hour at room temperature. Finally, washes were performed and the plate was developed with 50 μl of citrate buffer/tetramethylbenzidine (TMB) (3-3′-5-5′tetramethylbenzidine, 1 mg/ml) at 9:1 dilution and 1 ul/5 ml H 2 O 2 . The reaction was stopped by adding 2M H 2 SO 4 and the result was read at 450 nm. Anti-VRS M2 antibody of 8A4/G9 clone was used as primary antibody for antigen detection and then anti-mouse IgG labeled with HRP was used as detection antibody (secondary antibody). Polyclonal anti-VRS M2 antibody raised in rabbit in our own laboratory was used as positive control; in this case the secondary antibody is an anti-rabbit IgG antibody labeled with HRP. Controls using secondary antibody alone and no primary antibody were performed in order to determine that the secondary antibody reaction was specific to recognize the primary antibody, and also that the signal obtained is not caused by nonspecific binding of the secondary antibody to the viral antigen. Another control for determining that the reaction of the primary antibody is specific for the antigen, involved the use of antibodies on an ELISA plate that has not been activated with the antigen. The results ( FIG. 2 ) show that the monoclonal antibody of the invention is able to recognize 200 ng of purified antigen, the signal being stronger than even the positive control with polyclonal antibodies.
EXAMPLE 3
Assay to Determine the Efficiency of the Monoclonal Antibody to Detect Viral Antigens
[0025] The assay was performed to determine the maximum dilution of monoclonal anti-VRS M2 antibody of 8A4/G9 clone allowing the detection of viral antigen. For this, we used the same direct ELISA technique of Example 2, but in this case the plate was activated with 100 ng of purified antigen and anti-M2 antibody (425 μg/ml) was used at dilutions of 1 in 100, 1 in 1,000 and 1 in 2,000. The negative control was hMPV M2 protein as antigen, so as to determine that the antibody reaction is specific to RSV antigens and no for antigens of other virus. Controls using secondary antibody alone and no primary antibody were performed for determining that the reaction of the secondary antibody is specific to recognize the primary antibody, and also that the obtained signal is not caused by nonspecific binding of the secondary antibody to the viral antigen. Furthermore, in order to determine that the signal generated corresponded to the antibody-antigen specific binding, a control in which the ELISA plate was not activated with antigen prior antibodies incubation was performed. The results show ( FIG. 3 ) that the obtained signal, despite significantly increase the antibody dilution, is kept high, and the antibody of the invention does not react nonspecifically with the hMPV M2 protein. This shows that our monoclonal anti-M2 antibody at low concentration is able to specifically detect RSV antigens.
EXAMPLE 4
Sensitivity of Monoclonal Anti-M2 Antibody to RSV Antigens
[0026] This example corresponds to an assay carry out for determining the minimum amount of antigen that our monoclonal antibody can detect. Direct ELISA assays were performed, as mentioned in the above examples. In this case, the plate is activated with purified antigen using different amounts of antigen: 1 ug, 500 ng, 100 ng, 50 ng and 25 ng. The same test was performed in two groups where two dilutions of anti-M2 antibody (425 μg/ml) were evaluated: 1 in 100 ( FIG. 4A ) and 1 in 1,000 ( FIG. 4B ). Both dilutions were chosen because they had previously shown a strong signal in the purified antigen recognition. The two assay groups include a control in which the ELISA plate is not activated with antigen (control without antigen), a negative control with Adenovirus P8 protein for determining specificity of the antibody to RSV antigen, and a control in which only secondary antibody is used. The results show that the two antibody dilutions generate a similar signal and furthermore, the antibody is capable of detecting even 25 ng of pure antigen with a quite broad signal.
EXAMPLE 5
Detection of RSV Infected Cells by Flow Cytometry, using Anti-M2 Antibody
[0027] The objective of this assay is to demonstrate the wide range of techniques where you can use our monoclonal antibody. In the above examples, the monoclonal anti-M2 antibody was used in ELISA, and in this example the functionality of the antibody of the invention for detecting cell infection with RSV is assessed by flow cytometry. For this, HEp-2 cells infected with RSV and uninfected cells were used. Staining protocol was as follows: the cells were permeabilized with 1× PBS/0.2% Sapononin, stained with the monoclonal anti-RSV M2 antibody of 8A4/G9 clone (425 μg/ml) for 1 hour at 4° C. at two dilutions: 1 in 3,000 ( FIG. 5A ) and 1 in 7,500 ( FIG. 5B ) in 1× PBS/1% BSA, the cells were then washed with 1× PBS and centrifuged at 2,000 revolutions per minute (rpm) for 6 minutes, later they were resuspended in the same permeabilization buffer and stained with an anti-mouse IgG-FITC antibody diluted 1 in 1,000 in 1× PBS/1% BSA. Later, the cells were washed with 1× PBS and analyzed by flow cytometry. To demonstrate that the signal obtained in the flow cytometer is cause by binding of the anti-mouse IgG-FITC antibody (secondary antibody) to the antibody of the invention, a control in which only the secondary antibody was used is included. In addition, a positive control was included using an anti-RSV F protein antibody. Data obtained for both antibody dilutions were positive, as seen in FIG. 5 , where we can see a marked difference between infected cells and uninfected cells, leading to the conclusion that our antibody can recognize infected cells by flow cytometry. Note that in the positive control, the antibody was used at a dilution of 1 in 1,000, which is much larger than the dilution used with the antibody of the invention. That explains why a stronger signal was obtained with the positive control than the one obtained with monoclonal anti-M2 antibody.
EXAMPLE 6
Detection of RSV Infection by Immunofluorescence using the Monoclonal Anti-M2 Antibody
[0028] This assay was performed to widen the range of techniques that allows detecting RSV infection using the disclosed invention. A fluorescence microscopy assay where HEp-2 cells infected with RSV and uninfected were stained with monoclonal anti-M2 antibody was carried out. The protocol used was as follows: the cells were fixed with 1× PBS/4% formaldehyde/0.03M sucrose for 10 minutes at 4° C., then they were washed with 1× PBS, permeabilized with 1× PBS/0.2% Saponin for 5 minutes at room temperature, monoclonal anti-M2 antibody of the invention (425 μg/ml) was added at a dilution of 1 in 200 (2.125 mg/ml) in 1× PBS/1% BSA/0.2% Saponin/0.03 M Sucrose for 10 hours at 4° C. The samples were washed with 1× PBS/0.2% Tween for five minutes and then two washes with 1× PBS were performed. The secondary anti-mouse IgG-FITC antibody is added at a dilution of 1 in 500 in 1× PBS/1% BSA for 1 hour at room temperature. Washes were repeated and the nuclei were stained with Hoescht 33258 at a concentration of 5 ug/ml for 5 minutes at room temperature, and finally they were washed with 1× PBS and they were processed for observation in a fluorescence microscope. The obtained results show ( FIG. 6A ) that the antibody constituent of the invention is also useful to recognize infected cells by immunofluorescence.
[0029] For comparison, the same assay described above was carried out, but with a commercial monoclonal antibody specific for the F surface antigen of RSV, widely used today ( 6 B). Commercial antibody used is the murine antibody that detects the RSV F protein (anti-F antibody, Millipore MAB8599Clone 131-2A). In summary, HEp-2 cells infected with RSV were stained with the commercial antibody at a 1:200 dilution and then with a secondary anti-mouse IgG-FITC antibody at a dilution of 1 in 500. It was observed that the commercial antibody as able of detecting cells infected with RSV.
EXAMPLE 7
Comparative Assay Between Commercial Anti-F Antibody by Millipore and Monoclonal Anti-RSV M2 Antibody of 8A4/G9 Clone
[0030] This assay corresponds to a comparative analysis between our monoclonal anti-M2-1 antibody and the commercial monoclonal antibody specific for the F surface antigen of RSV (anti-F Millipore) in ELISA. The antibody anti-F is the same used in Example 6, in which an immunofluorescence assay was performed to detect cells infected with RSV. For determining the versatility of our antibody, in this assay our anti-M2-1 antibody was compared with the anti-F antibody from Millipore in a technique other than immunofluorescence. To perform this test, the ELISA plate was activated with viral particles (RSV) for 10 hours at 4° C. Later, the plate was blocked with 1% fish gelatine for 2 hours at room temperature, and then it was washed with 1× PBS/0.02% Tween and washed twice with 1× PBS. The plate was then incubated with the two antibodies to be compared, at a dilution of 1 in 1,000 for 2 hours at room temperature. Once the time of incubation was complete, washes were again carried out and then the plate was incubated with an antibody anti-mouse IgG labeled with HRP at a dilution of 1 in 1,500. Finally, washes were repeated and the ELISA was developed with Citrate Buffer/TMB (9:1) and H 2 O 2 (1 μl/5 ml of solution). The reaction was stopped with 50 μl of 2M H 2 SO 4 . The assay controls correspond to a negative control in which no sample was used (the plate was not previously activated with viral particles) to ensure that the signal is determined by RSV antigen recognition, and another control in which was used only secondary antibody for determining that the secondary antibody by itself does not recognize viral antigens. The results of this test are summarized in the graphs of FIG. 7 . They show that at a dilution of 1 in 1000, the commercial antibody is not able to detect RSV viral particles. However, the monoclonal M2-1 antibody is capable to recognize viral particles in such dilution. That is, the antibody of the invention is effective even at dilutions where other commercial antibodies are not able to detect the antigen. Furthermore, this assay demonstrates that our antibody is effective in a variety of techniques for antigen detection.
EXAMPLE 8
Comparative Assay Between Commercial Anti-F Antibody from Millipore, Anti-RSV DHI and Monoclonal Anti-RSV M2 Antibody of 8A4/G9 Clone
[0031] The antibodies compared in this ELISA assay were: monoclonal anti-M2-1 antibody of the invention, the monoclonal anti-F antibody from Millipore (Mab8599), and the monoclonal anti-RSV antibody from Diagnostic Hybrids (DHI, RSV MAbs 01-013302). The latter antibody was chosen for comparison because is widely used clinically for the diagnosis of patients positive for RSV infection and was facilitated by the centre for medical research of the Hospital Clínico de la Universidad Católica de Chile.
[0032] The comparative assay was carried out following the same procedure indicated in Example 7, except antibody dilutions were modified. In this case, a dilution of 1 in 100 was used for both monoclonal anti-F antibody and monoclonal anti-M2-1 antibody, and for the antibody RSV DHI a dilution 1 in 10 was used, as recommended by Diagnostic Laboratory, because a positive signal is obtained for RSV patients at that dilution. Similar to previous examples, a control with no sample, to see that the signal is determined by the recognition of RSV antigens and a control with secondary antibody only, to determine that our second antibody does not recognize viral antigens by itself, were added. The results obtained are shown in FIG. 8 and it can be seen that, at these dilutions, the commercial antibodies show no positive signal for the viral particles ( FIGS. 8B and 8C ), although the monoclonal M2-1 antibody was able to detect virus particles ( FIG. 8A ). It is worth mentioning that the use of a commercial RSV DHI antibody for diagnosis of RSV infected patients is standardized exclusively for fluorescence microscopy assays, reason that could explain no detection of RSV in ELISA. Moreover, obtaining a positive signal of monoclonal M2-1 antibody shows that this can be a valuable new tool for clinical diagnosis of RSV infected patients using the ELISA technique, currently not considered. It also opens the possibility of using this monoclonal antibody for the development of an immunodiagnostic kit.
EXAMPLE 9
Clinical Diagnosis of Samples of RSV Infected Patients using Monoclonal Anti-RSV M2-1 Antibody by ELISA
[0033] An ELISA assay was performed to verify the ability of the monoclonal antibody, which constitute the patent, to diagnose or detect RSV positive patients from clinical samples of nasopharyngeal swabs. Clinical samples were obtained from the Medical Research Center, Medical School, Pontificia Universidad Católica de Chile, samples that were previously diagnosed by immunofluorescence (method currently used for the diagnosis of the disease). Sandwich ELISA assays were performed on samples from patients, where the monoclonal anti-RSV M2 antibody was used to activate the plate in a dilution of 1 in 350, the plate was then blocked with 1% fish gelatin for 2 hours at room temperature. Followed by a wash performed with 1× PBS/0.02% Tween and two washes with 1× PBS, nasopharyngeal swabs samples were then incubated for 10 hours at 4° C. The samples were washed once again and incubated with a rabbit polyclonal anti-RSV M2 antibody for 2 hours at room temperature, in two dilutions: 1 in 1,000 and 1 in 2,000. Subsequently, washes were performed as described above and the samples were incubated with anti-rabbit IgG-HRP antibody (diluted 1 in 2000) and developed with citrate/TMB buffer (9:1) and 1 ul/5 ml H 2 O 2 . To stop the reaction 2M H 2 SO 4 was added. The assay was performed on samples of three patients positive for RSV ( FIGS. 9A to 9C ), one hMPV positive patient ( FIG. 9D ), a healthy patient ( FIG. 9E ) and negative controls without sample and without capture antibody for determining that the signal obtained is specific ( FIG. 9F ). The results show that the anti-M2 antibody is able to recognize specific RSV viral antigens of nasopharyngeal swabs. Therefore, the monoclonal antibody which defines the invention may be successfully used to detect RSV viral antigens in patient samples.
[0034] The examples described herein demonstrate the specificity, efficiency, sensitivity and versatility that our RSV monoclonal anti-M2-1 antibody secreted by the cell line of 8A4/G9 hybridoma possesses. Their advantageous characteristics over other commercially available antibodies which bind to RSV, make of our antibody an effective alternative for many uses both for detection and/or identification of RSV and for the generation of pharmaceutical compositions that allows treatment and/or prophylaxis of RSV infection. The examples presented herein are a demonstration of some of the uses of monoclonal anti-RSV M2-1 antibody, but in no way limit the scope of our invention.
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van den Hoogen, B. G., S. Herfst, et al. (2004). “Antigenic and genetic variability of human metapneumoviruses.” Emerg Infect Dis 10(4): 658-666.
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The use of monoclonal antibodies specific for respiratory syncytial virus (RSV). Specifically, to a monoclonal antibody IgG2A secreted by the cell line of 8A4/G9 hybridoma specifically directed to the M2-1 viral antigen, which is associated with the nucleocapside of the virus. The antibodies can be used for assays for the detection and/or determination of RSV infection. The antibodies are in the pure state and do not contain any other contaminating biological material. A method for preventing and treating the infection caused by respiratory syncytial virus (RSV) in a given host is provided, including the administration of a composition containing the monoclonal antibodies secreted by the 8A4/G9 hybridoma in sufficient doses to prevent the disease. The antibody can be humanized in order to minimize the possibility of an immune response against the same in the patient. In addition, it can be used to obtain any pharmaceutical form of the formulation of the monoclonal antibodies secreted by the 8A4/G9 hybridoma, which are suitable for the treatment or prevention of the disease caused by RSV. It also provides methods for detection and diagnosis of RSV viral antigens in biological samples using the monoclonal antibodies produced and secreted by cells of the 8A4/G9 hybridoma.
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FIELD OF THE INVENTION
[0001] The subject matter of the invention relates to a method for classifying the structured inner and/or outer surface of heat exchanger tubes which are seamless or have a longitudinal welded seam.
BACKGROUND OF THE INVENTION
[0002] According to the state of the art, surface-structured tubes are preferably utilized for heat transfer processes. These tubes are usually manufactured without a seam or are provided with a longitudinal welded seam. As a rule the tubes are copper tubes.
[0003] Tubes with a structured surface have a larger surface area than plain tubes. Tubes with a large surface area are preferably utilized in heat exchanger systems. The goal is to achieve enhanced performance densities for smaller sized products and lighter weight construction. For this it is necessary to improve the performance of the individual tubes.
[0004] The classification of structured tubes is accomplished usually at a high expense and with much time through the determination and analysis of the geometric magnitudes identifying the structure, such as structure heights and element angles. Examples of geometric structure magnitudes are, among others, described in detail in the EP 0 148 609. Therefore, for the classification of a geometric surface structure many individual measurements are needed. Besides the considerable technical measuring requirements, an accumulation of measurement errors may still occur.
[0005] To determine the heat transfer characteristics of a heat exchanger tube, it is necessary to carry out extensive measurements on individual tubes or bundles of tubes on a special heat-transfer test facility. Based on the background of the enormously large multitude of geometrical structured elements there arises the demand for a clear technically measured classification of the structure finenesses and their heat performance characteristics utilizing equipment clearly less complex compared with the state of the art.
SUMMARY OF THE INVENTION
[0006] The basic purpose of the invention is therefore to provide in place of the expensive, heat transfer measurement of individual tubes a method for the quick, clear and reproducible classification of structured surfaces. In particular a technical measurement capability operating without contact has been discovered and with which it is not necessary for a tube sample ready for use to be present.
[0007] This has been accomplished by providing a method for classifying the structured inner and/or outer surface of heat exchanger tubes with a longitudinal welded seam, wherein in each case a defined sample of the structured band, which is provided for the manufacture of the heat exchanger tube, is moved and subjected to a Doppler radar spectroscopy measurement using electromagnetic waves (microwaves) in the frequency range of 1 to 100 GHz, whereby the following magnitudes are determined from the standardized Doppler radar spectrum (standardized to the plain tube):
[0008] Surface integral A, average value m and variance S (or standard deviation σ={square root}{square root over (S)}) as well as a method for classifying the structured inner and/or outer surface of seamless heat exchanger tubes, wherein in each case a defined sample is moved from the surface of the heat exchanger tube, which surface is unrolled in a plane, and is subjected to a Doppler radar spectroscopy measurement using electromagnetic waves (microwaves) in the frequency range of 1 to 100 GHz, whereby the following magnitudes are determined from the standardized Doppler radar spectrum (standardized to the plain tube):
[0009] Surface integral A, average value m and variance S (or standard deviation σ={square root}{square root over (S)}).
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] [0010]FIG. 1 is a schematic illustration of a Doppler radar spectroscopy method employed in this invention;
[0011] [0011]FIG. 2 is a graph of frequency spectra standardized to a plain tube;
[0012] [0012]FIG. 3 a is a schematic representation of the surface integral A;
[0013] [0013]FIG. 3 b is a schematic representation of the average value m; and
[0014] [0014]FIG. 3 c is a schematic representation of the standard deviation σ.
DETAILED DESCRIPTION
[0015] The measuring method of the Doppler radar spectroscopy is schematically illustrated in FIG. 1. The electromagnetic waves sent at a specific angle from a microwave sender 1 in the frequency range of 1 to 100 GHz are thereby reflected by a moving sample 2 , are registered by a receiver 3 , and evaluated in a unit 4 . The arrow indicates the direction of movement of the sample. (Regarding the basics of the radar measuring technique, reference is made, for example, to the book of M. Skolnik “Introduction to Radar Systems”, McGraw-Hill (1980), in particular Page 68 and the following pages).
[0016] The resulting frequency shift based on the Doppler effect is measured. The structured surface of the moving band causes a geometric frequency spectrum increase in the reflected portion of the original monochromatically incident electromagnetic wave. This frequency or line spectrum increase is characteristic for the geometric structure of the surface and is noticeable after a Fourier frequency analysis of the reflected signal as a frequency spectrum in the range of the Doppler base frequency f 0 determined by the test parameters (compare the frequency spectra according to FIG. 2, which will be discussed later on, and which show spectra each standardized to the plain tube as a function of the Doppler shift (Hz)).
[0017] The following magnitudes are defined:
[0018] Surface integral A (compare schematic illustration in FIG. 3 a ),
[0019] average value m (compare FIG. 3 b ) and as measurement for the width
[0020] variance S (compare FIG. 3 c )
[0021] (or standard deviation σ={square root}{square root over (S)}).
[0022] These magnitudes can be illustrated mathematically in the following manner:
[0023] If f(x) is the distribution function of the Doppler radar frequencies x (standardized to a plain tube surface), that is, the Doppler radar spectrum of a structure to be examined, then the following applies:
Surface integral A ≡ ∫ - ∞ ∞ f ( x ) · x expected value or average value m ≡ ∫ - ∞ ∞ x · f ( x ) · x ∫ - ∞ ∞ f ( x ) · x variance S ≡ ∫ - ∞ ∞ ( x - m ) 2 · f ( x ) · x ∫ - ∞ ∞ f ( x ) · x standard deviation σ ≡ S
[0024] (compare, for example, Bronstein/Semendjajew: “Taschenbuch der Mathematik” (22 nd Edition, 1985), Page 665 to 668).
[0025] The method of the Doppler radar spectroscopy has up to now, for example, been utilized to examine the waviness of the surfaces of oceans (compare, for example, D. R. Thomphson: “Probing the Ocean Surface with Microwave Radar” in Johns Hopkins APL Technical Digest, Volume 10, Number 4 (1989), Pages 332-338, or R. Romeiser: “Doppler Spectra of the Radar Backscatter from the Sea Surface; Obtained from a Three-Scale Composite Surface Model” in International Geoscience and Remote Sensing Symposium (IGARSS) v 2, 1994, IEEEE, Piscataway, N.J., USA, 94CH3378-7, Page 729).
[0026] An application of the aforementioned subjects to the examining of the structured surface of heat exchanger tubes is not obvious for the man skilled in the art in particular due to varying orders of magnitude and varying speeds of the test objects.
[0027] The surface of common heat exchanger tubes can be classified according to the invention by the following areas:
[0028] 1×10 0 ≦A≦2×10 4 , in particular 1×10 1 ≦A≦5×10 3
[0029] 1×10 2 ≦S≦5×10 5 , in particular 1×10 3 ≦S≦1×10 5
[0030] (or 1×10 1 ≦σ≦1×10 3 , in particular 3×10 1 ≦σ≦5×10 2 ).
[0031] Within the scope of the invention it is found furthermore advantageously that a clear and reproducible correlation exists between the macroscopic surface topography, the specific parameter heat transfer coefficient α and the objective, integral characteristics of the Doppler radar spectra like surface integral A, average value m, variance S and standard deviation σ. Of particular importance is that the parameters of the Doppler radar spectra are suited for the heat transfer classification without requiring a detailed knowledge of the geometric sizes of the respective surface structures or tube samples ready for use.
[0032] The method of the Doppler radar spectroscopy is therefore well suited to classify any desired surface structures which are used, for example, to improve the specific thermal output of tubes for the heat transfer, in view of the to be expected thermal output of the tubes. The inventive relationship between the measured variables obtained through Doppler radar spectroscopy and the specific heat transfer performance of a tube sample ready for use is distinguished by an excellent reproducing ability of the data. The apparatus and time input is clearly lower compared with the state of the art.
[0033] In the case of tubes with structures, which are preferably utilized for use in liquifying processes, in particular in structures with sharp, convex edges (compare DE 44 04 357 C1), it has been shown that the Doppler spectrum average value m shifts to frequencies above the Doppler base frequency f 0 , and that an increase of the heat transfer coefficient α cond equals the increasing surface integral A of the Doppler radar spectrum. The variance S and the standard deviation σdecrease at the same time.
[0034] In the case of tubes with structures, which are preferably utilized in evaporation processes, in particular in undercut, cavity-like structures, it has been shown that a Doppler spectrum average value m shifts to frequencies below the Doppler base frequency f 0 , and that an increase of the heat transfer coefficient α evap equals the increasing surface integral A of the Doppler radar spectrum. The variance S and the standard deviation σ decrease at the same time.
[0035] The invention will be discussed in greater detail in connection with the following exemplary embodiments:
[0036] 1. Heat exchanger tubes of copper with an outside diameter of 9.52 mm. (⅜″) and a core wall thickness of 0.30 mm, which heat exchanger tubes are provided with a longitudinal welded seam, were examined according to the following Table 1. For example, a plain tube, a tube with a single inner fin structure and a tube with a double inner fin structure are listed.
TABLE 1 TUBE WITH TUBE WITH PLAIN SINGLE INNER DOUBLE INNER TUBE FIN STRUCTURE FIN STRUCTURE Tube 9.52 mm 9.52 mm 9.52 mm Dimension (⅜″) (⅜″) (⅜″) Fin Height — 0.20 mm 0.20 mm Core Wall 0.30 mm 0.30 mm 0.30 mm Thickness 1. Finning No. of Fins — 60 58 Angle Helix — 18° 30° 2. Finning No. of Fins — — 80 Angle Helix — — −10°
[0037] Copper alloys, aluminum, aluminum alloys and steel and special steel continue to be preferred as materials for the tubes.
[0038] Both the geometric sizes and also the thermal output were determined in the single tube test facility. The heat transfer measurements in the liquifying process resulted in the sequence plain tube, tube with a single fin structure and tube with a double fin structure in the performance relationships illustrated in Table 2a.
[0039] Parallel thereto, samples of bands used for the manufacture of the tubes were each mounted to a moving sample carrier. The plain surface or the inner structures were subsequently analyzed with the help of the Doppler radar spectroscopy. The examination was done with a 94 GHz radar module at a speed of the sample carrier of 2 m/sec.
[0040] [0040]FIG. 2 shows the Doppler radar spectra obtained in the case of the exemplarily listed tubes. The illustrated results are standardized to the spectrum of the plain tube.
[0041] The spectrum (a) relates to the tube with a single fin structure, the spectrum (b) to the tube with the double fin structure.
[0042] For the parameters surface integral A, variance S and standard deviation σ result the following values according to the Table 2b.
[0043] The good agreement of the ratio numbers regarding the α cond determined by heat transfer measurements and the surface integrals A determined from Doppler radar spectra are clearly noticeable.
[0044] The reciprocal numbers for S (or σ) at the same time correctly reproduce the relationship tendency in the performance data.
[0045] Furthermore the determined Doppler spectrum average values m lie above the Doppler base frequency f 0 registered for the plain tube, which is characteristic for condensation tubes.
[0046] 2. A plain tube, a tube with a single inner fin structure and a tube with a double inner fin structure, as they are utilized for evaporation processes, were examined in a second exemplary embodiment (compare the following Table 3).
TABLE 3 TUBE WITH TUBE WITH PLAIN SINGLE INNER DOUBLE INNER TUBE FIN STRUCTURE FIN STRUCTURE Tube 9.52 mm 9.52 mm 9.52 mm Dimension (⅜″) (⅜″) (⅜″) Fin Height — 0.20 mm 0.20 mm Core Wall 0.30 mm 0.24 mm 0.22 mm Thickness 1. Finning No. of Fins — 55 45 Angle Helix — 34° 0° 2. Finning No. of Fins — — 82 Angle Helix — — 42°
[0047] The heat transfer measurements in the evaporation process in the sequence plain tube, tube with single fin structure and tube with double fin structure resulted in the performance relationships illustrated in the Table 4a.
[0048] Samples of the bands used for the manufacture of the tubes were parallel thereto analyzed with the help of the Doppler radar spectroscopy. For the parameters surface integral A, variance S and standard deviation σresult the following values according to Table 4b.
[0049] The ratio of surface integrals A, determined from the Doppler radar spectra, just like the reciprocal values for S (or σ), correctly reproduce the tendency of the ratios of the heat transfer coefficient α evap . At the same time the Doppler spectrum average values m lying below the Doppler base frequency f 0 indicate that we are dealing with structures particularly suited for evaporation processes.
[0050] Thus the invention offers the possibility to draw from the measured variables A, S (or σ), m direct conclusions regarding the evaporating and liquifying performance of the respective surface structure.
TABLE 2a Plain Tube Measured Single Finned Tube Double Finned Tube Value Measured Measured Heat Value Value Transfer Heat Heat Coef- Transfer Transfer Mass ficient Ratio Coefficient Ratio Coefficient Ratio Flow α cond Ratio α cond Ratio α cond Ratio 200 2400 1 3700 1.5 5200 2.2 300 3000 1 4400 1.5 6500 2.2 400 3500 1 5000 1.4 8000 2.3 500 4200 1 5800 1.4 9400 2.2 600 4900 1 6900 1.4 10900 2.2 700 5600 1 8000 1.4 12600 2.3 in kg/m 2 s in W/m 2 K in W/m 2 K in W/m 2 K
[0051] [0051] TABLE 2b Single Double Plain Tube Finned Tube Finned Tube Measured Measured Measured Value Ratio Value Ratio Value Ratio Surface 26 1 41 1.6 63 2.4 Integral A Variance 93025 1 50703 1.8 35601 2.6 S Std. 305 1 225 1.4 189 1.6 Deviation σ Average 626 — 643 — 635 — value m (f 0 )
[0052] [0052] TABLE 4a Plain Tube Measured Double Finned Tube Value Single Finned Tube Measured Heat Measured Value Transfer Value Heat Coef- Heat Transfer Transfer Mass ficient Ratio Coefficient Ratio Coefficient Ratio Flow α evap Ratio α evap Ratio α evap Ratio 140 2600 1 5800 2.2 6200 2.4 160 2700 1 5600 2.1 6800 2.5 180 2900 1 5400 1.9 7250 2.5 200 3000 1 5200 1.7 7700 2.6 220 3000 1 5100 1.7 8000 2.7 in in W/m 2 K in W/m 2 K in W/m 2 K kg/m 2 s
[0053] [0053] TABLE 4b Single Double Plain Tube Finned Tube Finned Tube Measured Measured Measured Value Ratio Value Ratio Value Ratio Surface 26 1 65 2.5 97 3.7 Integral A Variance 93025 1 38097 2.4 32469 2.9 S Std. 305 1 198 1.5 180 1.7 Deviation σ Average 626 — 614 — 618 — value m (f 0 )
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A method for the quick classification of structured inner and/or outer surfaces of heat exchanger tubes by means of Doppler radar spectroscopy.
The measured variables to be determined from the frequency spectra:
Surface integral A, average value m and variance S (or standard deviation σ={square root}{square root over (S)}) correlate directly with the geometric parameters of the structure morphology. They permit direct conclusions regarding the heat transfer characteristics (evaporation/condensation performance) of the respective structure, in particular no tube samples ready for use are needed for the heat transfer classification.
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CROSS REFERENCE TO RELATED APPLICATIONS
This application is a continuation of Ser. No. 861,991 filed Feb. 18, 1992, abandoned, which was a continuation of Ser. No. 387,919 filed Jul. 31, 1989 abandoned, which was a continuation in part of Ser. No. 227,810 filed Aug. 3, 1988, abandoned.
FIELD OF THE INVENTION
The present invention is generally directed to inoculants for plants, and particularly directed to a biological inoculant effective in controlling root rot of plants, such as peas, caused by the fungus Aphanomyces euteiches.
BACKGROUND OF THE INVENTION
Farm crops are continually plagued by a variety of pests which can stunt or damage crop growth or even completely destroy the crop. Some of the pests are in the form of weeds which grow similarly to the desired plant and compete for the nutrients provided by soil and water. Other pests are in the form of pathogens such as fungi and bacteria which are found in association with many plants.
One of the more serious problems associated with fungal pathogens in plants is root rot. For example, pea root rot caused by the fungus Aphanomyces euteiches is a serious problem in pea-growing areas, particularly in Wisconsin and other Great Lake states. The Aphanomyces fungus infects not only peas, but also snap beans and alfalfa, accounting for 10 to 15% losses in yield. In extreme cases, some fields, where the fungus population has been built up over the period of several years, have become essentially useless for these crops.
Despite efforts to develop fungicides and commercially acceptable pea cultivars with resistance to this pathogen, there is presently no commercially available product capable of controlling Aphanomyces. Currently, the best way to avoid the disease loss is to avoid planting susceptible crops in soils with a high population of the Aphanomyces fungus. Unfortunately, the fungus can survive for many years in field soil and a long rotational time to other crops is not practical. As a result, there is a need to find an alternative disease control strategy to eliminate root rot caused by Aphanomyces and possibly other fungi.
There is increasing interest in the use of living organisms to control such diseases. Microscopic organisms are present in soil in populations of approximately 1 billion per cubic inch of soil. Some of the microorganisms cause disease and some are beneficial. The beneficial microorganisms are of major interest. It has long been known in agriculture that certain of these microbial inoculants can be used to facilitate the growth of certain plant species or to assist the plants in suppressing particular pathogenic organisms. For example, it has been a common practice to inoculate soybeans and other legumes at planting with bacterial cultures of the genus Rhizobium so that nitrogen-fixing nodules will form as a result of the plant-bacterium symbiosis.
Reference is now made to U.S. Pat. No. 4,588,584 to Lumsden, et al. which discloses a particular species of Pseudomonas cepacia which is effective in controlling Pythium diseases of cucumber and peas. There is also much literature on the use of Pseudomonas fluorescens as a biocontrol agent against various plant diseases, but not against the fungus Aphanomyces. The term "biocontrol agent", as used herein, refers to a living organism which controls diseases.
SUMMARY OF THE INVENTION
It is therefore an object of the invention to provide a biocontrol agent which is effective in biologically controlling pea root rot in the field.
It is also an object of the present invention to provide a biocontrol agent which is effective in reducing plant mortality in peas and other vegetable and field crops.
It is further an object of the present invention to provide a process for increasing the crop yield in Aphanomyces-infested soils.
These and other objects are met by the present invention which is directed to a process for controlling Aphanomyces fungal diseases of plants by inoculating the plants with an effective amount of an essentially biologically pure culture of a bacterial strain selected from the group consisting of strains AMMA, AMMD, PRA25, 5A, AM, CRK419, and mixtures thereof to control Aphanomyces.
The present invention is also directed to a process for increasing seed germination, decreasing plant mortality and increasing yield of a pea plant by inoculating the pea plant with a growth promotional effective amount of an essentially biologically pure culture of a bacterial strain selected from the group consisting of Pseudomonas cepacia and Pseudomonas fluorescens.
The present invention is also directed to a biological inoculant for controlling Aphanomyces fungal diseases on plants comprising an essentially biologically pure culture of a bacteria selected from the group consisting of strains AMMA, AMMD, PRAZ5, 5A AM, CRK419, and mixtures thereof.
The present invention is also directed to an agriculturally useful composition comprising a pea seed inoculated with an inoculant of either Pseudomonas cepacia or Pseudomonas fluorescens.
The inoculum which controls Aphanomyces on field crops, such as peas, is also disclosed in this invention. As used herein, the term "inoculum" means a biological control agent which is introduced onto a host substance or into soil. The inoculum comprises an essentially biologically pure culture of the bacteria mentioned in the previous paragraphs.
The bacterial strains and their process of use, disclosed in the present invention, represent a significant advance in controlling Aphanomyces. Because the bacterial strains are a biologically pure culture of a natural biological organism, massive quantities of the inoculum can be applied to the Aphanomyces infested area with little danger of environmental contamination. In view of public concern for ground water contamination and aerial pollution from pesticides, the form of control disclosed in the present invention is an attractive and economic alternative to chemical pesticides and other methods of control.
Other objects, advantages and features of the present invention will become apparent from the following specification when taken in conjunction with the accompanying drawing.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a graph illustrating the results of the mass spectrometric analysis of the fatty acid profile of Pseudomonas cepacia AMMA;
FIG. 2 is a graph illustrating the results of the mass spectrometric analysis of the fatty acid profile of Pseudomonas cepacia AMMD;
FIG. 3 is a graph illustrating the results of the mass spectrometric analysis of the fatty acid profile of Pseudomonas fluorescens PRA25: and
FIG. 4 illustrates a schematic view of a plant bioassay useful for observing biocontrol activity.
FIG. 5 is a graph illustrating the results of the mass spectrometric analysis of the fatty acid profile of Corynebacterium flaccumfaciens 5A.
FIG. 6 is a graph illustrating the results of the mass spectrometric analysis of the fatty acid profile of bacterial strain AM.
FIG. 7 is a graph illustrating the results of the mass spectrometric analysis of the fatty acid profile of bacterial strain CRK419.
DETAILED DESCRIPTION OF THE INVENTION
The present invention is directed to improving the growth and survival rate of field crops infested with the fungus Aphanomyces, and particularly the strain Aphanomyces euteiches, by inoculating the field crop with a biologically pure bacterial inoculant of the selected strains of the species Pseudomonas cepaci, Pseudomonas fluorescens, Corynebacterium flaccumfaciens, and a strain of Bacillus. The particular strains of the bacteria involved in the present invention were discovered by the inventor and are identified by the following nomenclature, as presently known:
Pseudomonas cepacia AMMA
Pseudomonas cepacia AMMD
Pseudomonas fluorescens PRA25
Corynebacterium flaccumfaciens 5A
Bacillus/Corynebacterium sp AM
Bacillus CRK419
The above-referenced bacterial strains were initially isolated from over 200 strains of bacteria associated with pea plants in the field. The bacterial strains Pseudomonas fluorescens PRA25 and strains 5A and AM were initially isolated from the rhizosphere of healthy appearing pea plants grown in soil at the University of Wisconsin - Arlington Experimental Farms Pea Root Rot Nursery, a naturally infested pea root rot area. The bacterial strains Pseudomonas cepacia AMMA and Pseudomonas cepacia AMMD were initially isolated from the rhizosphere of healthy appearing pea plants grown in containment in soil known to be infested with the Aphanomyces fungus from the University of Wisconsin-Arlington Experimental Farm. The strain of uncertain taxonomy (probably Bacillus) designated CRK419 was isolated from a corn field in which peas were previously cultivated near Fredonia, Ozaukee County, Wis.
The targeted bacterial strains were collected in the following manner. The root system from the pea plants was removed and agitated to shake off the excess soil. The hypocotyl and epicotyl segments of the roots were placed in distilled water, sonicated, and thereafter isolated in a plate dilution process, known to the art, in a TSAC (tryptic soy agar cyclohexamide) medium. Cyclohexamide is an anti-fungal agent. Colonies were thereafter selected and screened according to methods known to the art. The bacterial strains were thereafter stored in a DMSO solution at approximately -80° C. until required for use.
It has been found that the bacterial strains may be mass produced in culture with relative ease. The strains are cultured in a suitable culture medium such as a commercially available nutrient broth yeast (NBY) extract. As the bacterial strains grow and multiply, essentially biologically pure cultures of the strains are formed which may be collected. The term "biologically pure culture" is used herein to refer to cultures of bacteria that have essentially no concentration of other strains of bacteria.
The bacteria strains were then screened for biocontrol activity in soil which has been naturally infested or artificially infested with the Aphanomyces fungus in order to determine which bacterial strains are effective biocontrol agents.
The selected biocontrol agents were coated onto the plant seeds, e.g., the pea seeds, prior to planting. A preferred method for coating the seeds is to combine the bacterial strain with a biologically non-interfering liquid carrier for application onto the seeds. A carrier shall be deemed "biologically non-interfering" if it does not prevent the bacterial strains from growing, and if it does not affect Aphanomyces in the absence of the bacteria. The nutrient medium in which the bacteria were cultured has been found to be a satisfactory medium. A suitable fungicide, i.e., captan, may also be coated on the seeds. The cultures survive air-drying after seed coating. The preferred carrier is a water-based liquid, preferably sterile distilled water.
Although coating the seed with the bacterial strain is preferred, other processes which provide a convenient means for distributing the bacterial strain to the Aphanomyces fungi fall within the scope and spirit of the invention. For example, the bacterial strain may be directly applied to the soil prior to planting the seeds.
Whether the inoculant is coated actually on the plant seed or inserted into the furrows into which the seeds are planted, the inoculant is preferably diluted with a suitable carrier or extender so as to make the inoculant easier to handle and to provide a sufficient quantity of material so as to be capable of easy human handling. Examples of suitable carriers include water, granular minerals, such as vermiculite, soils or peat.
To enable others to obtain a culture of these strains, samples have been deposited with the American Type Culture Collection (ATCC), being identified by the accession number and date of deposit as follows:
______________________________________ ATCC Date ofBacterial Strain Accession No. Deposit______________________________________Pseudomonas cepacia AMMA 52796 7/22/88Pseudomonas cepacia AMMD 53795 7/22/88Pseudomonas fluorescens PRA25 53794 7/22/88Corynebacterium flaccumfaciens 5A 53934 7/26/89Bacillus/Corynebacterium AM 53933 7/26/89Bacillus CRK419 53935 7/26/89______________________________________
To further identify the bacterial strains, a fatty acid profile for each rhizosphere culture was determined by mass spectrometric analysis. The term "rhizosphere", as used herein, refers to the zone of soil subject to the influence of the plant roots.
With reference to FIG. 1, the results of the tests to determine the fatty acid profile for Pseudomonas cepacia AMMA are presented below in Table 1:
TABLE 1__________________________________________________________________________RT Area Ar/Ht Respon ECL Name % Comment 1 Comment__________________________________________________________________________ 2 1.61340785000 0.081 -- 7.051 SOLVENT PEAK <min rt 4.4471548 0.036 1.036 12.000 12:0 0.98 ECL deviates Ref 0.000 6.8284415 0.038 0.969 14.000 14:0 2.63 ECL deviates Ref -0.001 9.1088547 0.042 0.944 15.493 Sum In Feature 3 4.95 ECL deviates 14:003 30H/16:1 ISC 9.63627640 0.042 0.941 15.819 16:1 CIS 9 15.97 ECL deviates 0.002 9.92825281 0.044 0.940 15.999 16:0 14.58 ECL deviates -0.001 Ref -0.00211.4379844 0.047 0.936 16.890 17:0 CYCLO 5.66 ECL deviates Ref 0.00011.7141646 0.047 0.936 17.052 16:1 20H 0.95 ECL deviates 0.00512.0341188 0.047 0.936 17.236 16:0 20H 0.68 ECL deviates 0.00112.5349443 0.048 0.937 17.524 16:0 30H 5.43 ECL deviates 0.00412.937733 0.047 -- 17.757 --13.05373016 0.048 0.937 17.824 Sum In Feature 7 42.01 ECL deviates -0.001 18:1 TRANS 9/t6/c1113.3561307 0.046 0.938 17.998 18:0 0.75 ECL deviates -0.002 Ref -0.00214.143904 0.066 -- 18.452 -- --14.9225361 0.050 0.943 18.901 19:0 CYCLO C11-12 3.10 ECL deviates Ref 0.00115.2513969 0.055 0.945 19.091 18:1 20H 2.30 ECL deviates 0.003******8547 -- -- -- SUMMED FEATURE 3 4.95 12:0 ALDE ? unknown 10.9******-- -- -- -- -- 16:1 ISO I/14:0 14:0 30H/ 16:1 ISO I******73016 -- -- -- SUMMED FEATURE 7 42.01 18:1 CIS 11/t 9/t 18:1 TRANS 9/t6/c11******-- -- -- -- -- 18:1 TRANS 6/t9/c11__________________________________________________________________________Solvent Ar Total Area Named Area % NAmed Total Amnt Nbr Ref ECL Deviation Ref ECL__________________________________________________________________________ Shift40785000 174842 173205 99.06 162924 6 0.002 0.001__________________________________________________________________________TSBA [Rev 2.0] Pseudomonas 0.440 P. cepacia 0.440 P. c. cepacia GC subgroup B 0.440__________________________________________________________________________Comparison with TSBA [Rev 2.0 ]: Pseudomonas-cepacia-cepacia GC subgroupB Distance: 3.8051015202530354045505560657075................12:0-*--...............11:0 ISO.30H.*-...............13:1 AT 12-13*-...............14:0-+X---..............16:1 CIS 9..----------*------ ---..........16:1 C*...............16.0...-X----*-----..........17:0 CYCLO.----X+-----.............17:0*-...............16:1 20H-*-...............16:0 20H-*-...............16:0 30H.-+X-..............18:0-*-...............19:0 CYCLO-X+-------... ..........C11-1218:1 20H--*--..............SUMMED.-*-..............FEATURE 3SUMMED......-----*---------X.......FEATURE 7__________________________________________________________________________
With reference to FIG. 2, the results of the fatty acid profile for Pseudomonas cepacia AMMD are presented below in Table 2:
TABLE 2__________________________________________________________________________RT Area Ar/Ht Respon ECL Name % Comment 1 Comment__________________________________________________________________________ 1.61340748000 0.081 -- 7.052 SOLVENT PEAK -- <min rt 4.4461993 0.031 1.036 12.000 12:0 1.00 ECL deviates Ref -0.001 6.8265489 0.038 0.969 14.000 14:0 2.59 ECL deviates -0.000 Ref -0.002 9.1079988 0.042 0.944 15.493 Sum In Feature 3 4.59 ECL deviates 14:003 30H/16:1 ISO 9.63430599 0.043 0.941 15.818 16:1 CIS 9 14.02 ECL deviates 0.001 9.92836362 0.044 0.940 16.000 16:0 16.63 ECL deviates Ref -0.00210.0831560 0.070 -- 16.092 --11.43616563 0.048 0.936 16.890 17:0 CYCLO 7.55 ECL deviates Ref 0.00011.7141747 0.046 0.936 17.052 16:1 20H 0.80 ECL deviates 0.00512.0341387 0.049 0.936 17.237 16:0 20H 0.63 ECL deviates 0.00212.53211342 0.048 0.937 17.524 16:0 30H 5.17 ECL deviates 0.00412.9341066 0.044 -- 17.756 --13.05186323 0.047 0.937 17.823 Sum In Feature 7 39.38 ECL deviates 18:1 CIS 11/t 9/t613.3541722 0.047 0.938 17.998 18:0 0.79 ECL deviates -0.002 Ref -0.00314.1431445 0.067 -- 18.453 --14.4891051 0.057 -- 18.652 --15.9219636 0.048 0.943 18.901 19:0 CYCLO C11-12 4.42 ECL deviates Ref 0.00015.2495288 0.057 0.945 19.091 18:1 20H 2.43 ECL deviates 0.00317.1371003 0.043 -- 20.191 -- >max rt******9988 -- -- -- SUMMED FEATURE 3 4.59 12:0 ALDE ? unknown 10.9******-- -- -- -- -- 16:1 ISO I/14:0 14:0 30H/ 16:1 ISO I******86323 -- -- -- SUMMED FEATURE 7 39.38 18:1 CIS 11/t 9/t 18:1 TRANS 9/t6/c11******-- -- -- -- -- 18:1 TRANS 6/t9/c11__________________________________________________________________________Solvent Ar Total Area Named Area % Named Total Amnt Nbr Ref ECL Deviation Ref ECL__________________________________________________________________________ Shift40748000 223561 218439 97.71 205479 6 0.002 0.002__________________________________________________________________________TSBA [Rev 2.0] Pseudomonas 0.591 P. cepacia 0.591 P. c. cepacia GC subgroup B 0.591__________________________________________________________________________Comparison with TSBA [Rev 2.0]: Pseudomonas-cepacia-cepacia GC subgroupB-Distance: 3.0051015202530354045505560657075................12:0-*--...............11:0 ISO 30H.*-...............13:1 AT 12-13*-...............14:0-+X---...... ........16:1 CIS 9..--------*-+---------..........16:1 C*...............16.0...-------X-+-----..........17:0 CYCLO.------+X----.............17:0*-...............16:1 20H-*-...............16:0 20H-*-...............16:0 30H.-+X-..............18:0- *-...............19:0 CYCLO---*------.............C11-1218:1 20H--*--..............SUMMED.-*-..............FEATURE 3SUMMED......-----+-----X-.......FEATURE 7__________________________________________________________________________
With reference to FIG. 3, the results of the tests to determine the fatty acid profile for Psuedomonas fluorescens PRA25 are presented below in Table 3:
TABLE 3__________________________________________________________________________RT Area Ar/Ht Respon ECL Name % Comment 1 Comment__________________________________________________________________________ 21.61340050000 0.080 -- 7.047 SOLVENT PEAK -- <min rt3.9584169 0.030 1.069 11.429 10:0 30H 5.14 ECL deviates 0.0064.4441045 0.039 1.041 12.000 12:0 1.26 ECL deviates Ref -0.0025.7595852 0.036 0.996 13.181 12:0 20H 6.72 ECL deviates 0.0036.1224845 0.037 0.988 13.460 12:0 30H 5.52 ECL deviates 0.0059.63230810 0.043 0.942 16.818 16:1 CIS 9 33.48 ECL deviates 0.0019.92529005 0.043 0.941 15.999 16:0 31.46 ECL deviates -0.001 Ref -0.00211.4341943 0.045 0.935 16.889 17:0 CYCLO 2.10 ECL deviates Ref 0.00113.04613300 0.045 0.934 17.821 Sum In Feature 7 14.32 ECL deviates -0.001 18:1 CIS 11/t 9/t617.779528 0.026 -- 20.569 -- >max rt******13300 -- -- -- SUMMED FEATURE 7 14.32 18:1 CIS 11/t 9/t 18:1 TRANS 9/t6/c11******-- -- -- -- -- 18:1 TRANS 6/t9/c11__________________________________________________________________________Solvent Ar Total Area Named Area % Named Total Amnt Nbr Ref ECL Deviation Ref ECL__________________________________________________________________________ Shift40050000 90969 90969 100.00 86707 3 0.003 0.002__________________________________________________________________________TSBA [Rev 2.0] Pseudomonas 0.661 (P. fluorescens D) P. chlororaphis 0.661 (P. fluorescens D) P. aureofaciens 0.515 (P. fluorescens E) P. fluorescens 0.422 P. f. A. 0.422 P. f. G. 0.320 P. f. C. 0.265__________________________________________________________________________Comparison with TSBA [Rev 2.0]: Pseudomonas-chlororaphis (P. fluorescensD)-Distance: 2051015202530354045505560657075................10.0 30H.-+X-..............12:0X+ -...............12:0 20H.-+-X..............12.1 30H*-...............12:0.30H.+-X..............14:0*-...............16:1 CIS 9.......-X-+----........16:0......---+X---.........17:0.CYCLO--*--..............18:0*-...............SUMMED...---X+----...... ......FEATURE 7__________________________________________________________________________
FIG. 5 illustrates the fatty acid profile, determined by mass spectrometer for strain 5A. The exact taxonomical classification of strain 5A is not certain, although it is in the Corynebacterium or Bacillus groups, and it is currently believed that the organism is properly classified as Corynebacterium flaccumfaciens. It is a gram positive, non-motile rod and on NBY forms smooth bright yellow colonies, with margins entire. The bacterial are aerobic, catalese positive, oxidase negative and grow on TTC agar. To further firmly fix the species classification, it would be necessary to perform a thin layer chromatographic analysis of the whole organism methanolysates. The results of the fatty acid analysis are recapitulated in the following Table 4:
TABLE 4__________________________________________________________________________RT Area Ar/Ht Respon ECL Name % Comment 1 Comment__________________________________________________________________________ 21.61340717000 0.081 -- 7.051 SOLVENT PEAK <min rt6.3284354 0.036 0.979 13.618 14:0 ISO 1.23 ECL deviates -0.000 Ref -0.0037.74734292 0.040 0.956 14.621 15:0 ISO 9.51 ECL deviates -0.000 Ref -0.0027.884198650 0.040 0.955 14.713 15:0 ANIEISO 54.98 ECL deviates Ref 0.0008.3101069 0.043 0.950 15.000 15:0 0.29 ECL deviates -0.000 Ref -0.0029.32168683 0.042 0.943 15.625 16:0 ISO 18.77 ECL deviates -0.001 Ref -0.0039.92711080 0.043 0.940 16.000 16:0 3.02 ECL deviates -0.000 Ref -0.00210.9935560 0.045 0.937 16.629 17:0 ISO 1.51 ECL deviates Ref -0.00211.15039366 0.045 0.937 16.722 17:0 ANIEISO 10.69 ECL deviates Ref -0.00316.4341161 0.365 -- 19.784 -- -- >max ar/ht17.9082771 0.261 -- 20.644 -- -- >max rtSolvent Ar Total Area Named Area % Named Total Amnt Nbr Ref ECL Deviation Ref ECL__________________________________________________________________________ Shift40717000 364215 363054 99.68 345020 8 0.001 0.002TSBA [Rev 2.0] Bacillus 0.161 B. polymyxa 0.161__________________________________________________________________________Comparison with TSBA [Rev 2.0]: Bacillus-polymyxa Distance: 5.670051015202530354045505560657075................11:0 ISO30H.*-...............14:0 ISO- X+-...............14:0X-+ -...............15:0 ISO.-----+--X-.............15:0 ANIEISO..........-------X----+------------.15:0*-...............16:0 ISO.-------+------X......... ...16:1 AX+--...............16:0. X - - - +- - - -...............17:0 ISO.-X+--..............17:0 ANIEISO.---+--X.............__________________________________________________________________________
The strain AM is also not unequivocally classified. It appears to belong to the Bacillus polymyxa/circulans/macerans group. It may also, however, be Corynebacterium as well. With reference to FIG. 6, the results of the fatty acid profile for strain AM are presented below in Table 5:
TABLE 5 RT Area Ar/Ht Respon ECL Name % Comment 1 Comment 1.613 40608000 0.081 -- 7.052 SOLVENT PEAK <min rt 1.811 815 0.020 -- 7.485 -- -- <min rt 6.021 620 0.037 0.985 13.381 14:0 ISO E 0.15 ECL deviates -0.007 6.329 3574 0.036 0.979 13.618 14:0 ISO 0.84 ECL deviates -0.000 Ref -0.002 7.749 41315 0.040 0.956 14.621 15:0 ISO 9.53 ECL deviates -0.000 Ref -0.001 7.886 217290 0.041 0.955 14.713 15:0 ANIEISO 50.05 ECL deviates 0.002 Ref 0.001 8.311 968 0.042 0.950 14.999 15:0 0.22 ECL deviates -0.001 Ref -0.001 9.325 82543 0.042 0.943 15.626 16:0 ISO 18.78 ECL deviates 0.000 Ref -0.001 9.928 11351 0.044 0.940 15.999 16:0 2.57 ECL deviates -0.001 Ref -0.002 10.995 12426 0.044 0.937 16.629 17:0 ISO 2.81 ECL deviates 0.000 Ref -0.001 11.153 66566 0.044 0.937 16.722 17:0 ANIEISO 15.04 ECL deviates 0.000 Ref -0.001 14.004 805 0.050 -- 18.372 -- -- 14.494 808 0.053 -- 18.655 -- -- Solvent Ar Total Area Named Area % Named Total Amnt Nbr Ref ECL Deviation Ref ECL Shift 40608000 438266 436653 99.63 414520 8 0.002 0.001 TSBA [Rev 2.0] Bacillus 0.021 B. circulans 0.021 B. polymyxa 0.014 Comparison with TSBA [Rev 2.0]: Bacillus-circulans Distance: 8.257 051015202530354045505560657075 ................ 13:0 ISO*--.......... 14:1 ISO*-.... ........... 14:0 ISO-X---+------------------........... 14.0X---+----.............. 15:0 ISO-------+-X-------------........... 15:0 ANIEISO......-------------------+- -X---------------.. 15:0*-......... 16:0 ISO E*--............... 16:0 ISO--------+---------X-........... 16:1 AX--+-----.............. 16:0---X--------+--- -----------------....... 17:0 ISO-+-X-............... 17:0 ANIEISO.-----+--------X............
The strain CRK419 is a Bacillus strain, perhaps of Bacillus firmus. Referring now to FIG. 7, the results of the fatty acid profile of the Bacillus strain CRK419 is presented referring also to the following Table 6:
TABLE 6 RT Area Ar/Ht Respon ECL Name % Comment 1 Comment 1.613 40859000 0.081 -- 7.054 SOLVENT PEAK <min rt 6.326 1464 0.037 0.979 13.616 14:0 ISO 0.38 ECL deviates -0.002 Ref -0.005 6.829 5020 0.038 0.969 14.002 14:0 1.28 ECL deviates 0.002 Ref 0.000 7.749 33670 0.039 0.956 14.621 15:0 ISO 8.47 ECL deviates -0.000 Ref -0.001 7.884 47762 0.040 0.955 14.711 15:0 ANIEISO 12.00 ECL deviates 0.000 Ref 0.000 8.314 920 0.047 0.950 15.001 15:0 0.23 ECL deviates 0.001 Ref 0.001 9.326 1334 0.037 0.943 15.626 16:0 ISO 0.33 ECL deviates -0.000 Ref 0.000 9.381 6042 0.045 0.943 15.659 unknown 15.665 1.50 ECL deviates -0.006 9.539 4827 0.046 0.942 15.757 16:1 A 1.20 ECL deviates 0.000 9.636 4396 0.044 0.941 15.817 16:1 CIS 9 1.09 ECL deviates 0.000 9.695 4484 0.042 0.941 156.853 Sum in feature 4 1.11 ECL deviates -0.003 16:1 TRANS 9/15i20H 9.783 958 0.042 0.941 15.908 16:1 C 0.24 ECL deviates -0.000 9.933 108370 0.043 0.094 16.001 16:0 26.80 ECL deviates 0.001 Ref 0.001 10.484 2818 0.046 0.938 16.385 17:1 ISO E 0.70 ECL deviates -0.002 10.745 1397 0.054 0.937 16.480 Sum in feature 5 0.34 ECL deviates 0.004 17:1 ISO I/ANTEI B 10.996 11597 0.046 0.937 16.628 17:0 ISO 2.86 ECL deviates -0.001 Ref -0.001 11.154 10474 0.044 0.937 16.721 17:0 ANIEISO 2.58 ECL deviates -0.001 Ref -0.000 11.274 1078 0.058 0.936 16.792 17:1 B 0.27 ECL deviates 0.000 11.438 833 0.053 0.936 16.889 17:0 CYCLO 0.21 ECL deviates 0.001 Ref 0.001 12.866 2291 0.054 0.937 17.716 Sum in feature 6 0.56 ECL deviates -0.004 18:2 CIS 9,12/18:0a 12.961 26913 0.046 0.937 17.771 18:1 CIS 9 6.64 ECL deviates 0.002 13.055 98867 0.048 0.937 17.825 Sum in feature 7 24.39 ECL deviates 0.000 18:1 TRANS 9/t6/c11 13.358 5115 0.049 0.938 18.000 18:0 1.26 ECL deviates 0.000 Ref -0.001 14.379 3110 0.053 -- 18.591 -- -- 14.570 3110 0.045 -- 18.701 -- -- 14.765 4691 0.047 0.943 18.814 19:1 TRANS 7 1.16 ECL deviates -0.009 14.863 17717 0.048 0.943 18.871 Sum in feature 9 4.40 ECL deviates 0.004 19:0 CYCLO C9-10/un 16.278 6987 0.047 -- 19.689 -- -- 17.787 4189 0.049 -- 20.569 -- -- >max rt 17.953 10626 0.047 -- 20.665 -- -- >max rt 18.156 2298 0.052 -- 20.784 -- -- >max rt 19.384 1248 0.069 -- 21.499 -- -- >max rt 19.590 12895 0.049 -- 21.619 -- -- >max rt ****** 4484 -- -- -- SUMMED FEATURE 4 1.11 15:0 ISO 20H/16:1t9 16:1 TRANS 9/15i20H ****** 1397 -- -- -- SUMMED FEATURE 5 0.34 17:1 ISO I/ANTEI B 17:1 ANTEISO B/i ****** 2291 -- -- -- SUMMED FEATURE 6 0.56 18:2 CIS 9,12/18:0a 18:0 ANTEISO/18:2 ****** 98867 -- -- -- SUMMED FEATURE 7 24.39 18:1 CIS 11/t 9/t 6 18:1 TRANS 9/t6/c11 ****** -- -- -- -- -- -- 18:1 TRANS 6/t9/c11 ****** 17717 -- -- -- SUMMED FEATURE 9 4.40 un 18.846/18.858 un 18.858/ .846/19c ****** -- -- -- -- -- -- 19:0 CYCLO C9-10/un Solvent Ar Total Area Named Area % Named Total Amnt Nbr Ref ECL Deviation Ref ECL Shift 40859000 416245 403038 96.83 379910 11 0.003 0.002 TSBA [Rev 2.0] *NO MATCH* Comparison with TSBA [Rev 2.0]: Bacillus-firm us Distance: 73.724 051015202530354045505560657075 ................ 14:0 ISOX--+------............. 14.0-X-+-----.............. 15.1 ANTEISOX+----............. . A 15:0 ISO-------X-----------------+---------- .. 15:0 ANIEISO----------X------+-------------------------....... -- 15:0X+ 16:1 ISO EX----+----------- ----........... 16:1 ISO.H*-............ 16:0 ISOX--------+------------------------......... unknown 15.665+X...... 16:1 A-X--+----------............ 16:1 CIS 9+X............... 16:1 .. CX+-- 16:0--------+----------------X---------........ 17:1 ISO.E-X+---..... 17:1 ANIEISO.*-............ ... A 17:0 ISO--+X-.............. 17:0 ANIEISO---X+-----............. 17:1 B*-............... 17:0 CYCLO*-........ 18:1 CIS 9+-.X.............. 18:0-*- -............... 19:1 TRANS .. 7+X.... SUMMED-*----.............. FEATURE 4 SUMMEDX--+-------............. FEATURE 5 SUMMED+X............... FEATURE 6 SUMMED+-... .X........... FEATURE 7 SUMMED+-X............... FEATURE 9
The following non-limitative examples are designed to illustrate the present invention:
EXAMPLES
Example 1
Example 1 was conducted to isolate and determine particular bacterial strains which are effective biocontrol agents for the Aphanomyces fungus. Approximately 200 bacterial strains were isolated from pea roots grown in Wisconsin soils infested with Aphanomyces. Each isolate was grown in a nutrient broth (NBY) and coated onto a captan-treated pea seed (Perfection 8221). The term "captan" refers to a fungicide having the chemical name N-(Trichloromethylthio) tetrahydrophthalimide. The coated seeds were air-dried prior to planting.
The coated seeds and the control seeds were then planted in 60 cc. cone-shaped containers, as illustrated in FIG. 4, containing either pasteurized soil or naturally infested (with Aphanomyces) field soil. Unless otherwise defined, the control in each of the experiments was a captan-treated pea seed. The pasteurized soil was inoculated with 2×10 4 Aphanomyces zoospores six days after planting. The plants were then grown under greenhouse conditions for approximately three weeks, after which the disease symptoms and shoot dry weights were measured.
The following bacterial strains, listed in Table 7, were identified as the best strains in terms of improvement in shoot dry weights and decreased disease symptoms over control conditions:
TABLE 7______________________________________Bacterial % Shoot Wt. IncreaseStrain Compared to Control______________________________________CRK449 19.55A 19.9CRK424 20.0AMMD 20.2PRA44 20.2CRK419 20.6PRA25 21.2PRA42 22.6PRA48 23.0CRK468 25.1CRK478 27.7PRA15 45.2AMMA 52.7______________________________________
The bacterial strains which showed the greatest promise in reducing pea root rot and disease severity, as well as increasing shoot dry weight, were then tested under field conditions (Examples 2 and 3).
EXAMPLE 36
Example 2 was designed to test the twelve bacterial strains, which showed the greatest promise from Example 1, for biocontrol activity. The bacterial strains were cultured and coated onto pea seeds according to the methods described in Example 1. The seeds were then planted in a plot of 17 foot rows of 100 seeds each, each replicated 5 times in a randomized block design. The plants were allowed to grow for one season (8 weeks). Plant mortality was evaluated weekly and the plant yield was determined using the dry weight of the pea plants measured. It is to be noted that the disease was so prevalent in this experiment that no pea pods formed. The results of Example 2 are presented below in Table 8.
TABLE 8______________________________________Bacterial Mean Shoot %Strain Dry Wt., g Difference**______________________________________control 61 --PRA48 36 -41PRA44 44 -28CRK424 47 -23CRK168 61 +1CRK468 66 +8PRA42 68 +12PRA15 69 +22CRK419 79 +31PRA25 85 +415A 92* +52AMMD 94* +55AMMA 103* +70______________________________________ *P less than .05 Dunnett Test **Between the treatments (Bacterial Strain) and the control.
EXAMPLE 3
This example, which is similar to Example 2, comprised field trials conducted in locations representing a range of Aphanomyces densities. Example 3 was designed to test five bacterial strains plus a control. The methods and materials were conducted in a manner similar to Example 2. The plant mortality due to Aphanomyces was evaluated weekly. Plant yield was determined using the dry weight of the peas at dry seed stage. The results of this experiment are presented below in Table 9.
TABLE 9______________________________________ Mean Dry % YieldBacterial Strain Wt. Peas, g Difference______________________________________control 175 --AM 158 -105A 189 8PRA25 210 12CRK419 215 23AMMD 282 61______________________________________
From Table 3, it can be seen that the bacterial strain AMMD increased the average seed yield by 61%, compared to the non-coated controls.
EXAMPLE 4
Like Example 3, Example 4 was designed to test strains of bacterial in the field. Six bacterial strains plus a control were tested under conditions similar to Example 2. Unlike Example 2, the yield here was determined using the fresh weight of peas. The results of Example 4 can be found below in Table 10:
TABLE 10______________________________________ Mean Fresh % YieldBacterial Strain Wt. Peas, g Difference______________________________________control 105 --UW85 119 13CRK419 155 41PRA25 166 585A 177 69AMMD 188 79AM 209* 99______________________________________ *P less than .05 Dunnett Test.
Several bacterial strains increased pea yield by 13-99%. Pseudomonas cepacia strain AMMD increased yield by 79%, and Pseudomonas fluorescens strain PRA 25 increased yield by 58% compared to the control treatment. It is to be noted that none of the bacterial strains increased the pea yield in fields with less than 1 Aphanomyces propagule per gram of soil.
The next experiments, Examples 5-13, were designed to provide information as to how the bacterial strains work. Although the mechanism of biocontrol by the bacteria is unknown, it has been suggested from tests conducted in petri dishes that the biocontrol bacteria produce a substance which limits the growth of the fungus. This substance may act as an antibiotic in reducing the growth of the fungus in the soil.
EXAMPLE 5
Example 5 was conducted to test the effects of the bacterial cultures on the Aphanomyces zoospores. Prior to conducting the test, it was determined that the growth medium, a 1% solution of NBY broth, does not affect the motility of Aphanomyces zoospores. The bacterial strains Pseudomonas cepacia AMMD and Bacillus cereus (UW85) were grown in the NBY growth medium under conditions explained previously with respect to culturing the bacterial strains. The bacterial strains were then diluted to 1% of their original solution and added to a petri dish containing zoospores of the Aphanomyces fungus. The Aphanomyces zoospores were tested for motility after 30 minutes exposure to the bacterial strains, and cyst germination was quantified after 6 hour exposure to the bacterial strains. Cyst germination is a test of the viability of the fungus.
The motility rating scale is as follows:
0=no motility
1=a few motile cells
2=roughly half
3=most cells motile
4=full motility as seen at initial release in check treatment.
After 30 minutes exposure to the bacteria and the controls (lake water and 1% NBY broth), the effects on zoospore motility are presented on Table 11:
TABLE 11______________________________________Bacterial Strain Motility______________________________________lake water* 3.0NBY* 3.0Bacillus cereus 1.6AMMD 0.2______________________________________ *Control
Table 12 below illustrates the effect of exposure of the bacterial strains and controls to cyst development in the Aphanomyces fungus after 6 hours:
TABLE 12______________________________________Bacterial Strain % Germlings______________________________________NBY* 58.6AMMD 22.6lake water* 17.4Bacillus cereus 13.6______________________________________ *Control
Replicates of these procedures also demonstrated that AMMA also eliminates zoospore motility in 10 minutes and delays cyst germination.
EXAMPLE 6
Example 6 was conducted to compare the effects of certain bacterial strains with a control treatment in zoospore motility of Aphanomyces fungus. The experimental procedure described in Example 5 was followed. The effects on zoospore motility was observed 10 minutes after the bacterial strains (or control) was added to the Aphanomyces treatment. The results are illustrated below in Table 13.
TABLE 13______________________________________Treatment* Motility______________________________________broth alone 2.0AM 2.0PRA25 1.9CRK419 1.9BC 1.85A 1.4AMMA 0.0AMMD 0.0______________________________________ *Values are means of 5 replicates.
EXAMPLE 7
Example 7 was conducted to compare the effects of different bacterial strains on mycelial growth, zoospore motility and cyst germination of Aphanomyces. The experimental procedure of Example 5 was followed with respect to Example 7. The results of Example 7 are illustrated below in Table 14.
TABLE 14______________________________________Bacterial Mycelial Zoospore CystStrain Growth Motility Germination______________________________________AMMA +++* +++ +++AMMD +++ +++ +++PRA25 +++ - -AM +++ - -CRK419 -** - -5A - + -UW85 +*** - -______________________________________ *cessation of activity **no change in activity ***slight decrease in activity
EXAMPLE 8
Example 8 was conducted to compare the effects of the bacterial strain Pseudomonas cepacia AMMD with a control (NBY broth) on cyst germination. The procedure of Example 5 was used with respect to Example 8. The results of this experiment are illustrated below in Table 15.
TABLE 15______________________________________Treatment % Cyst Germination______________________________________broth alone 58.6AMMD 22.6______________________________________
EXAMPLE 9
Example 9 was designed to test the in vitro effects of Psuedomonas cepacia AMMD on Aphanomyces zoospores. The Pseudomonas cepacia AMMD bacterial strain was compared to three controls: (1) lake water; (2) cell-free filtrate from NBY-AMMD culture: and (3) NBY growth broth alone. All solutions were diluted to 1% of original in milli-Q water. The motility of the zoospores was rated according to the table illustrated in FIG. 5. Table 16 below illustrates the mean of 5 repetitions at 10 and 30 minutes from the following treatments:
Treatment 1--lake water control
Treatment 2--AMMD in NBY broth
Treatment 3--Cell-free filtrate from NBY-AMMD culture
Treatment 4--NBY broth alone
TABLE 16______________________________________Time Treatment: 1 2 3 4______________________________________10 min. 3.4 0 3.6 2.630 min. 3.8 0 3.4 2.8______________________________________
As illustrated in Table 16, Pseudomonas cepacia AMMD in the NBY broth eliminates zoospore motility after 10 minutes. However, the NBY broth alone and the cell-free cultures of AMMD do not effect zoospore motility.
EXAMPLE 10
Example 10 was conducted to test the effects of sugar beet seeds coated with certain bacterial strains on Aphanomyces cochlioides zoospores. Sugar beet seeds were coated with the bacterial strains and planted in a growth chamber under conditions similar to Example 1. The soils were inoculated 6 weeks later with 20 ml. of 103 zoospores per milliliter of Aphanomyces cochlioides. Approximately 6 weeks later, the plants were harvested and the shoots dried and weighed. The results of the shoot dry weight are illustrated below in Table 17.
TABLE 17______________________________________Treatment Shoot Dry Wt. (mg).sup.1______________________________________Control 5330BC 48045A 5716AMMD 9199*AM 11533*AMMA 11742*______________________________________ .sup.1 Values are means of 15 replicates per treatment. Values marked wit an asterisk are significantly different than the controls (Dunnett's test p = 0.05).
The bacterial strains Pseudomonas cepacia AMMA, AM, and AMMD significantly increased sugar beet shoot dry weight compared to the control treatment without bacteria.
EXAMPLE 11
Example 11 was conducted to compare the effects of various bacterial strains with or without the addition of captan on the emergence of pea shoots. The tests were conducted in soil naturally infested with Aphanomyces euteiches. Pea seeds were coated with the bacteria using the same procedure as for Example 1. In one experiment, treated seeds were planted into flats of soil in the greenhouse. The next experiment was conducted in the field using only three of the bacteria. In both cases, seeds without bacteria served as the check treatments. The results of Example 11 are shown below in Table 18.
TABLE 18__________________________________________________________________________Effects of Bacteria On Pea Emergence. % EmergenceBacterial Treatment: None 5A PRA25 AMMA AM CRK419 AMMD__________________________________________________________________________Greenhouse Experimentwith captan 84 e 79 e 88 de 92 e 85 e 81 e 62 cwithout captan 13 a 29 ab 63 cd 61 c 31 b 25 ab --Field Experimentwith captan 88 d 92 d 88 d 89 dwithout captan 40 a 56 b 56 b 72 c__________________________________________________________________________
Treatments within each experiment that are not followed by the same letter are significantly different at the P=0.05 level using the Least Significant Difference test.
As illustrated in Table 18, the bacteria strain Pseudomonas cepacia AMMA and Pseudomonas fluorescens PRA25 significantly improved pea emergence from seeds not treated with captan in the greenhouse experiment. Comparing seeds without captan in the field experiment, Pseudomonas cepacia AMMD and Pseudomonas fluorescens PRA25 significantly increased the emergence of peas compared to those without bacteria. None of the bacteria tested improved the emergence of peas treated with captan.
EXAMPLE 12
This example was conducted to examine the effects of strains PRA25 and AMMD on pre-emergence damping off caused by the fungal pathogen Pythium. Four soils naturally invested with Pythium species were used for this greenhouse experiment. Each replicate consisted of 25 pea plants planted in each of four sorts. Pea seeds without captan were coated with PRA25 or AMMD as previously described and planted in flats containing infested soil. Untreated seeds without bacteria or captan, and seeds treated with captan were used as controls. There were three replicates per treatment, and the protocol was repeated three times. Percentage of pea seedling emergence was determined eight days after planting. The results of these experiments are summarized in the following Table 19.
TABLE 19______________________________________Pea Seedling Emergence in Pythium-infested soilsSeed Treatment Rochelle Arlington Hancock Muck______________________________________Untreated 46.7 32.0 45.7 49.7PRA25 72.0 51.5 81.3 42.7AMMD 91.5 89.8 92.9 63.5Captan 95.5 95.1 97.3 77.8______________________________________
EXAMPLE 13
This example was a test of the effectiveness of these bacterial inoculants derived from pea fields on Pythium ultimum disease in cucumber. Cucumber seeds variety "Straight Edge" were planted into potted soils invested with the pathogenic Pythium and were inoculated with an overnight liquid culture of the strains tested. Cucumber seeds were treated with the commercial standard fungicide "Apron" or with a standard root clonizing bacteria, designated "standard" for controls. In addiiton untreated seeds were planted both in infected and uninfected soils as controls. Emergence and post-emergence damping off are expressed as percentages in the following Tables 20 and 21. Stand represents a percentage of total plants surviving of those planted and vigor was calculated on the mean distance to first leaf compared to the control.
TABLE 20______________________________________Treatment % Emergence % Damping-Off % Stand______________________________________Test 1Uninoculated 80 0 80Inoculated 68 35 44Apron 96 0 96Standard 90 16 785A 90 13 80AM 72 21 58AMMA 92 18 78AMMD 94 28 70CRK419 64 43 40PRA25 88 16 80Test 2Uninoculated 92 0 92Inoculated 70 38 46Apron 98 0 98Standard 98 0 985A 89 13 76AM 82 2 80AMMA 96 9 88AMMD 78 8 72CRK419 72 12 62PRA25 98 0 98______________________________________
TABLE 21______________________________________ % % % %Treatment Emergence Damping-Off Stand Vigor______________________________________Uninoculated 100 0 100 100Inoculated 74 15 66 72Apron 100 0 100 104Standard 100 0 100 83AMMA 98 3 95 92AMMD 96 0 96 95PRA25 96 2 94 106______________________________________
It is understood that the invention is not confined to the particular construction and arrangement herein illustrated and described, but embraces such modified forms thereof as come within the scope of the following claims:
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A bacterial inoculant is disclosed for controlling root rot in peas caused by Aphanomyces fungus. The inoculum is obtained from general bacterial strains including strains of Pseudomonas cepacia, Pseudomonas fluorescens, Corynebacterium flaccumfaciens, and two other Bacillus strains of uncertain taxonomy.
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RELATED APPLICATIONS
[0001] This application claims priority to U.S. Provisional Patent Application Ser. No. 61/904,608 filed on Nov. 15, 2013 entitled “Solar Energy Disaggregation Techniques for Whole-House Energy Consumption Data.” This application also claims priority to U.S. Provisional Patent Application Ser. No. 61/754,436 filed on Jan. 18, 2013, entitled “Novel Applications Using Appliance Load Profiles Generated from Non-Intrusive Load Monitoring.”
BACKGROUND OF THE INVENTION
[0002] The present invention is generally directed to systems and methods of non-intrusive appliance load monitoring (“NIALM”). Specifically, the present invention is directed to different techniques for disaggregating low resolution data to determine certain or specific appliance usage.
[0003] Appliance load monitoring is an effective way to communicate to users the amount of energy usage required by various appliances. Presenting users with such information in an understandable format allows users to take appropriate action to actively reduce total energy consumption. Moreover, providing itemized information per specific appliance also permits users to determine if acquiring a new or replacement appliance (for example, through purchase, lease, or rental) would reduce energy costs sufficient to validate the price of purchase, lease, or rental. NIALM enables the breakdown of electricity usage for a property without entering the property or applying any sub-metering devices on the individual appliances/devices/loads inside the property. In general, NIALM is known in the prior art. For example, U.S. Pat. No. 4,858,141 to Hart et al. (“Hart”) discusses basic techniques for performing NIALM. Hart teaches generating and using appliance load signatures to extract information for individual loads from whole property load profile data measured by the utility meter. As taught by Hart, information extracted from the utility meter may comprise: power consumption; times when the appliance/load was turned on and off; and appliance/load health.
[0004] There has been research in the area of NIALM and various papers have been published on techniques used to define load signatures and run pattern recognition algorithm on the load profile of the property under inspection. Typically, a software analysis is performed on past data collected Therefore such prior art techniques may be useful in breaking down the energy usage or itemizing the electric energy bill post-consumption, but fail to provide near real-time information that may immediately empower users to modify their energy usage. With regard to appliances such as heating or air conditioning—for which usage is based upon immediate conditions—such data of previous usage may provide limited assistance in modifying present behavior and usage.
[0005] However, prior art techniques generally fail to account for an input that may be provided by home-installed power generating devices—specifically, solar panels. Yet, the inclusion of such information is desirable in order to provide more accurate results and to assist both utilities and consumers reduce energy consumption, peak load and renewable allocation, and increase utility operational effectiveness. In addition, even if a consumer does not have a home equipped with power generating devices, such as solar panels, techniques that include solar panel calculations may be desirable in order to provide actual, home-specific, information to a consumer of the potential impact such devices may have on the consumer's home and energy usage.
[0006] Moreover, prior art techniques and methodologies may provide users with some basic information regarding their power consumption—but fail to provide the user with any additional advice or counseling as to how to effectively use the information to reduce energy consumption. Rather, the user is left with the notion that he or she should simply use particular appliances less often. This information is relatively meaningless with regard to appliances that users generally must use—for example, refrigerators, electric ranges, washing machines, dryers, etc. In addition, with regard to economic efficiency, the time of energy usage may dictate the cost of such usage. For example, during peak energy usage times, utility companies may charge increased rates than during low usage times. Merely changing the time of day a particular appliance is used may result in significant cost savings.
SUMMARY OF THE INVENTION
[0007] Some aspects in accordance with some embodiments of the present invention may include aspects in accordance with some embodiments of the present invention may include a method for remotely setting, controlling, or modifying settings on a programmable communicating thermostat (PCT) in order to customize settings to a specific house and user, comprising: receiving at a remote processor information entered into the PCT by the user; receiving at the remote processor: non-electrical information associated with the specific house or user; and energy usage data of the specific house; performing by the remote processor energy disaggregation on the energy usage data; determining by the remote processor a custom schedule for the PCT based upon the information entered by the user, the non-electrical information associated with the specific house or user, and disaggregated energy usage data; revising by the remote processor, the custom schedule for the PCT based upon additional user input or seasonal changes; providing the custom schedule for the PCT to the PCT.
[0008] Some aspects in accordance with some embodiments of the present invention may include a method for remotely setting, controlling, or modifying settings on a programmable communicating thermostat (PCT) in order to customize settings to a specific house and user, comprising: receiving at a remote processor information entered into the PCT by the user, the information comprising temperature set points and start and end times, the information received via a network connection between the PCT and the processor; receiving at the remote processor: non-electrical information associated with the specific house or user, non-electrical information received from a plurality of information sources, including publicly available database and weather data; and energy usage data of the specific house, received from a utility, Smart Meter, or measuring device; performing by the remote processor energy disaggregation on the energy usage data, the energy disaggregation comprising determining any contribution from solar panels and adjusting for such contribution; determining by the remote processor a plurality of custom schedules for the PCT based upon the information entered by the user, the non-electrical information associated with the specific house or user, and disaggregated energy usage data; revising by the remote processor, the custom schedule for the PCT based upon additional user input or seasonal changes; providing the custom schedule for the PCT to the PCT.
[0009] Some aspects in accordance with some embodiments of the present invention may include a method for remotely setting, controlling, or modifying settings on a programmable communicating thermostat (PCT) in order to customize settings to a specific house and user, comprising: receiving at a remote processor information entered into the PCT by the user; receiving at the remote processor: non-electrical information associated with the specific house or user; and energy usage data of the specific house; performing by the remote processor energy disaggregation on the energy usage data; determining by the remote processor one or more custom schedules for the PCT comprising an active schedule that is implemented by the PCT when the specific house is determined to be occupied, a passive schedule that is implemented by the PCT when the specific house is determined to not be actively occupied, and/or a not-at-home schedule, that is implemented by the PCT when the specific house is determined to not be occupied, the customer PCT schedules based upon the information entered by the user, the non-electrical information associated with the specific house or user, and disaggregated energy usage data; revising by the remote processor, the custom schedule for the PCT based upon additional user input or seasonal changes; providing the custom schedule for the PCT to the PCT.
[0010] These and other aspects will become apparent from the following description of the invention taken in conjunction with the following drawings, although variations and modifications may be effected without departing from the scope of the novel concepts of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The present invention can be more fully understood by reading the following detailed description together with the accompanying drawings, in which like reference indicators are used to designate like elements. The accompanying figures depict certain illustrative embodiments and may aid in understanding the following detailed description. Before any embodiment of the invention is explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangements of components set forth in the following description or illustrated in the drawings. The embodiments depicted are to be understood as exemplary and in no way limiting of the overall scope of the invention. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The detailed description will make reference to the following figures, in which:
[0012] FIG. 1 depicts exemplary sources and resolution of data sets that may be used in systems and methods in accordance with some embodiments of the present invention.
[0013] FIG. 2 illustrates an exemplary net power signature over a three (3) day period, in accordance with some embodiments of the present invention.
[0014] FIG. 3 illustrates an exemplary solar power signal over a three (3) day period, in accordance with some embodiments of the present invention.
[0015] FIG. 4 depicts an exemplary flow for a training and prediction algorithm, in accordance with some embodiments of the present invention.
[0016] FIG. 5 illustrates an exemplary graph indicating predicted solar power and ground truth solar power for a tested home, in accordance with some embodiments of the present invention.
[0017] FIG. 6 depicts an exemplary scenario combining both energy efficiency and demand response goals in a solution, in accordance with some embodiments of the present invention.
[0018] FIG. 7 illustrates an exemplary scenario combining both energy efficiency and demand response goals in a solution, in accordance with some embodiments of the present invention.
[0019] FIG. 8 illustrates an exemplary interaction between energy use data and a programmable communicating thermostat (PCT), in accordance with some embodiments of the present invention.
[0020] FIG. 9 depicts an exemplary algorithm illustrating an interaction between energy use data and a programmable communicating thermostat (PCT), in accordance with some embodiments of the present invention.
[0021] Before any embodiment of the invention is explained in detail, it is to be understood that the present invention is not limited in its application to the details of construction and the arrangements of components set forth in the following description or illustrated in the drawings. The present invention is capable of other embodiments and of being practiced or being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.
DETAILED DESCRIPTION
[0022] The matters exemplified in this description are provided to assist in a comprehensive understanding of various exemplary embodiments disclosed with reference to the accompanying figures. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the exemplary embodiments described herein can be made without departing from the spirit and scope of the claimed invention. Descriptions of well-known functions and constructions are omitted for clarity and conciseness. Moreover, as used herein, the singular may be interpreted in the plural, and alternately, any term in the plural may be interpreted to be in the singular.
[0023] Note that while the preceding and following disclosure primarily discusses monitoring and reporting electric usage, it is fully contemplated by the applicants that such systems and methods disclosed herein may also be used to monitor other types of energy consumption—for example natural gas, propane, and water consumption.
[0024] As stated above, the present invention is generally directed to novel applications of non-intrusive appliance load monitoring and solar energy disaggregation. Note that the solutions set forth in the present invention that are directed or include solar energy disaggregation are also applicable to consumers who are not equipped with solar generation, as such solutions may provide unequipped consumers with data and information relating to potential energy savings under various levels of solar capacity. Such information may assist consumers in identifying any potential and optimal solar panel installation.
[0025] The systems and methods of the present invention are unique over the prior art for a number of reasons. For example, the present invention is capable of predicting solar output on unseen homes using training data from different locations around the world. This predictive model may be applicable to locations other than where it was trained. For example, a model may be trained on the west coast of the United States (e.g., California), but may be used to predict solar output on the east coast of the United States (e.g., Connecticut).
[0026] Moreover, disaggregation models in accordance with some embodiments of the present invention may be used to derive solar capacity for a specific home by reviewing and analyzing a historical net power signature of the home. Such models may not require any special hardware to be installed at or on the home to predict such solar capacity. For example, such disaggregation models may determine that solar capacity may be a function of the square footage and orientation of the solar panels, without requiring actual input of either variable.
[0027] Techniques for energy disaggregation may be determined and/or impacted by the type of data and/or how the data is obtained or accessed. For example, data types may include power signals, or meteorological data or conditions. Power signals may be obtained in low frequency or high frequency samples. Low frequency data may be sampled—for example—hourly, while high or higher frequency data may be sampled—for example—each minute. Meteorological data or conditions may include information such as, but not limited to, (i) skycover or cloud cover (which may be set forth as a percentage or ratio of cover to clear sky); (ii) temperature; (iii) wind-speed; (iv) dew point; and (v) sunrise/sunset times.
[0028] Data may be obtained and/or accessed in various manners. For example, a current clamp (CT clamp) may be utilized. The use of two (2) CT clamps may generally be required, with one CT claim positioned at or proximate to the net meter (which may indicate net power draw for the house), and a second CT clamp positioned at or proximate to the solar system (which may indicate power captured and contributed by the solar system). Alternatively, energy usage data may be obtained from Green Button (an industry effort to provide transparent energy usage data, which is generally provided in hourly intervals); from Smart Meters—for example using a Smart Meter Home Area Network channel; from a Zigbee connection (which, utilizes data captured by the Zigbee alliance that sets forth energy consumption data); or from a direct connection to a solar company, for example through the use of an application programming interface (API) that connects with a solar company to obtain energy data (either net usage or solar contribution).
[0029] Based upon various combinations of data sets, different techniques may be used to disaggregate the data. Exemplary data sets in accordance with some embodiments of the present invention may be seen in FIG. 1 . Current government policies and the consumer attitudes are driving the electric, gas and water utilities to make the consumer energy, water and gas consumption data available. This information may be used by the consumers or consumer authorized third parties for specific presentation and analytics. At least one goal of the availability of such information is to empower consumer with actionable information and influence consumer behavior to participate in energy saving actions.
[0030] Yet, the consumption data collected by utilities may not always have the highest resolution and therefore information may be lost when the data is sampled. For example, this may result when data is collected at large time intervals or low frequency sampling.
[0031] However, utilizing methods and systems disclosed herein and according to some embodiments of the present invention, the consumption data captured by utilities may be analyzed, possibly with the aid of separately collected high resolution data. The analytics generated and results or conclusions may be applied to the low resolution data, therefore making it possible to help consumers save energy on a larger scale. This may be accomplished even though the data from utilities alone may not include information specific enough to generate same analytical results.
[0032] With reference to FIG. 1 , sources of data 100 and exemplary resolution of such data 200 will now be discussed. Sources of data 100 may vary, and may comprise elements such as: information from a processing utility 110 (which may be thought of as “back office” information, or information that is used by the utility typically for billing purposes, note that customer consent is likely need to obtain this information); information from a utility web site 120 (for example a customer may download account information and provide the same; alternatively, the customer may provide a third party with access and the third party may “scrape” the website of the utility); directly from the smart meter if there is a home area network 130 ; an additional, consumer installed, meter or usage sensor 140 ; an additional meter or usage sensor installed by a third party (not the utility) 150 ; or any other sort of data input 160 .
[0033] The resolution of the data 200 may, in general, be divided into three categories of high resolution 210 , medium resolution 220 , and low resolution 230 . High resolution data 210 may be sampled at a higher frequency, for example every millisecond or microsecond. Medium resolution data 220 may be sampled at a frequency of around every few seconds. Low resolution data 230 may be sampled at a low frequency, for example every several minutes or every hour.
[0034] In order to provide reliable, reasonably specific NILM on low frequency data, several overarching techniques may be used. For example, a first technique may comprise estimating a portion of energy from the whole house waveform that is attributed to a specific appliance category. Some appliances—for example: pool pumps, air conditioners, furnaces, etc.—may be able to be culled out of the whole house waveform. A second technique may be to use a training set to assist the system in learning the energy consumption patterns of various appliance categories in relation to specific signatures and/or parameters.
[0035] In order to properly “train” a system to disaggregate results from low resolution data, training data may be utilized. Training data may comprise a data set with medium or high resolution, and comprising information required to process non-intrusive load monitoring (“NILM”) in order to extract information associated with individual appliances.
[0036] In contrast to the training data, actual data (or “test data”) may comprise a low resolution data set that may not have sufficient content to process NILM algorithms. Such test data may be used to process high-level analysis, but results are generally inferior to analyses that process medium or high resolution data.
[0037] Note that training data can be data received from the actual home in question—for example, through user training directed at specific appliances in the home—or can be data associated with any number or plurality of other homes, neighborhoods, communities or other information. For example, in order to obtain more accurate results, a user can train appliances in his or her home. This data directly corresponds to the appliances used in the home. Accordingly, even when low resolution data is received, medium or high resolution training data provided by the user can be used to determine individual and/or specific appliance load profiles.
[0038] Alternatively, a user may not undergo the time or effort of training, instead relying upon a larger database of both non-electric data and training data received from others. In this situation, various features of the user's home (which may, for example, be identified through the use of non-electrical data, such as square footage, age of construction, heating or cooling degree days, etc.) may be identified in the training data.
[0039] Groupings of the training data may be utilized to provide a feature classification based upon the most comparable data. For example, home size may provide grouping. Data associated with a 1200 square foot home may not provide sufficiently comparable data to determine the load on a heating or cooling system used in a 4500 square foot home. Similarly, homes built during the same time period in the same geographic area are likely to have comparable insulation. Even the number of residents of a home may provide information useful in grouping the data. A home with two adults and five children will generally require laundry machines to run more often than single-person homes. Homes with pools may require the use of a periodic pool pump. Each of these features can be associated with stored training data.
[0040] Accordingly, low resolution data can be processed through a trained classifier or a regression model to determine the likely presence and operation of one or more specific appliances. The use of a trained classifier and/or regression model is discussed in further detail below.
Techniques Used for Low Frequency Consumption Data
[0041] When using low frequency whole-house energy consumption data, the energy contribution of solar panels must be determined and disaggregated. Such disaggregation may be based upon meteorological data. In general, such determination may be made by (i) estimating the solar panel capacity for a specific home; (ii) predicting the solar intensity of the specific home; (iii) based upon the capacity and intensity, predicting solar generation; and (iv) disaggregating the solar energy produced from the low frequency whole-house energy consumption data.
[0042] In accordance with some embodiments of the present invention, certain techniques for disaggregating low frequency energy consumption data that includes solar panel generation will now be discussed. With reference to FIG. 2 , an exemplary net power signature for a specific home over a three (3) day period can be seen. This exemplary net power signature represents the net usage of the home, including any contribution from solar panels. FIG. 3 indicates an exemplary solar power signal over the same three (3) day period. It can be seen from the net power curve in FIG. 2 that the net power becomes negative between sunrise and sunset. Similarly, in FIG. 3 it can be seen that the solar power signal is generally represented by a single major curve per day, between sunrise and sunset.
[0043] Solar Panel Capacity Estimation.
[0044] Solar panel capacity may be defined as the maximum output of solar panel in kilowatts (kW). This capacity may generally be estimated by examining historical net power signatures. Based upon historical net power signatures, Solar Capacity may be determined by the following equation:
[0000] SolarCapacity=−1×(Baseload−min(DayNet))
[0045] Where “Baseload” equals the lower 20 th percentile of net power used by a home during the night (i.e., when there is no or negligible solar contribution), and “DayNet” equals the net power from sunrise to sunset (i.e., appliance consumption minus solar generation).
[0046] Note that the signal of the solar panel is always negative since it produces energy. Solar power is generated the most during the day causing the net power signal to become negative. The minimum of net during the day cannot be deemed alone to be the solar capacity, since there are generally other appliances being used during the day which may cause the net power to be generally higher than the solar power generated. Accordingly, a Baseload may be calculated as the lower 20 th percentile of the net power during the night when solar power is not present. This lower 20 th percentile represents that twenty (20) percent of the appliances active during the day are also active during the night. The use of the 20 th percentile was determined through a grid search and produces greater accuracy when comparing ground-truth solar capacity and estimated capacity.
[0047] Solar Intensity Prediction.
[0048] Next, a regression model may be trained with weather data and the number of hours from sunrise to sunset as one or more independent variables, and solar intensity as the dependent variable.
[0049] Solar intensity may be seen as the normalized version of solar generation, and may be stated in the range from 0 to 1. Normalization of the dependent variable may be desirable when using a regression model, because it generally permits or allows the model to be easily trained. In accordance with some embodiments of the present invention, a radial basis function (RBF) support vector machine combined with RBF neural networks may be used. RBF support vector machine and RBF neural networks are machine learning algorithms that may create highly complex non-linear models.
[0050] While various other machine learning models and algorithms may be utilized without deviating from the present invention, RBF models may be selected because such models strive to fit Gaussian curves to the data, and is accordingly suited for Gaussian-shaped solar panel generation curves. Such Gaussian-shaped solar panel generation curves may be seen in FIG. 3 .
[0051] Machine learning models may then be optimized in any number of ways as known in the art. For example, optimization may be performed by obtaining optimal model parameters, 10-fold cross validation, and regularization. For example, models learned based upon data collected over a year for one hundred (100) homes, and were tested upon approximately twenty-five (25) homes to confirm results. Support Vector Machines and neural networks achieved desirable results when given a large amount of training data. Solar intensity testing predictions were accurate—and were recorded at higher accuracies than previous testing—despite training data being obtained from various homes in different parts of the world.
[0052] Solar Generation Prediction.
[0053] With reference to FIG. 4 , an exemplary flow for training and predicting solar generation based upon low frequency consumption data, in accordance with some embodiments of the present invention, will now be discussed. At 410 , a preprocess may be applied to the data set, for example to remove outliers and clean the data from identifiable noise. At 420 a support vector machine (SVM) and neural network (NN) model may be trained (as noted above) with previously acquired data. At 430 solar and weather data may be normalized, and a 440 a solar intensity may be determined. Solar intensity may be based upon the prediction model coupled with identifiable weather features. In addition to solar intensity at 440 , at 450 a solar capacity may be determined, based upon the equation noted above. Based upon both the solar intensity and the solar capacity, at 460 the solar generation may be predicted.
[0054] Based upon the earlier results of the estimated capacity and determined solar intensity prediction, solar generation prediction may be obtained by multiplying the estimated capacity with the solar intensity prediction. The prediction is now transformed back to the KW range. With reference to FIG. 5 , an example of a predicted solar panel generation and ground truth generation for a specific home, in accordance with some embodiments of the present invention is depicted.
[0055] Solar Energy Disaggregation.
[0056] Finally, predicted solar generation may be subtracted from the net power of the specific home, thereby disaggregating the contribution of solar energy from the low frequency whole-house energy consumption data.
Techniques Used for High Frequency Consumption Data
[0057] While high frequency data may be useful in providing more accurate energy predictions, high frequency energy consumption data may include an increase in noise, and may be more difficult to correlate meteorological data (which is generally very low resolution) with such high frequency data.
[0058] Solar Signal and Appliance Signal Differentiation.
[0059] With high frequency data sampled at the one minute level, solar power may be quite noisy. For example, the curve of solar power contribution generated for an exemplary day may include several spikes (for example, due to constantly changing meteorological conditions such as cloud cover). Such spikes may not be merely smoothed, since while spikes may be caused by weather fluctuations, they may also be caused by an appliance being used at the same time. Accordingly, techniques may be desirable that may differentiate spikes from solar signals caused by weather or by appliance usage. In accordance with some embodiments of the present invention, techniques of differentiating such spikes may comprise: (i) identifying correlations between weather and spikes in the data; (ii) establishing spikes caused by weather; (iii) determining features used in appliance usage by using waveform characteristics and transitions; (iv) training a classification model with two (2) classes: weather caused spikes and appliance usage spikes; and (v) performing disaggregation only on spikes that are not determined to be caused by weather.
[0060] Solar Energy Prediction and Disaggregation.
[0061] Weather features may then be extrapolated from data sampled hourly or by the minute. The solar energy prediction algorithm and models discussed above with low frequency energy data may then be used to accurately predict solar energy contribution, which may then be deducted from the net power in order to obtain solar energy disaggregation.
Applications of Disaggregated Energy Data
[0062] Once energy is disaggregated, there are various uses to which such information can be used. For example, such information may be used to (i) provide a solution combining both energy efficiency and demand response; (ii) interact with a programmable communicating thermostat (PCT) for a consumer's benefit; (iii) enable targeted outreach to specific consumers or specific classes of consumers (for example, based upon usage characteristics); and (iv) provide measuring and verification of purported or promised benefits—both from utilities and from other service providers (for example, to track the actual contribution of solar panels, or to determine if appliances are obtaining promised energy usage levels). Each of these are discussed in turn below.
[0063] (i) Combining Energy Efficiency and Demand Response.
[0064] Many utilities, today, offer Demand Response and Energy Efficiency as two separate programs to consumers. Consumer adoption of Demand response programs is low, potentially because, in most cases, consumers do not see any ongoing benefit from the program. Utilities on the other hand may be able to reduce peak load and therefore avoid blackouts when the generation capacity is close to peak demand.
[0065] The current investment by utilities in the Smart Meter infrastructure may allow use of Energy Disaggregation to create a holistic solution that benefits both for consumers and utilities—energy savings for consumers (and utilities with efficiency mandates) and load reduction for utilities.
[0066] While a Programmable Communicating Thermostat (PCT) is often seen by some to be the most obvious device in the house that can serve the application, other devices may (for example a load control switch with a capability to talk to Smart Meters) be used instead of a PCT to realize the combination of energy efficiency and demand response. In addition, such application may also be implemented by combining multiple devices in the house.
[0067] Hardware involved may include: (a) a smart meter installed by the utility; and (b) a programmable communicating thermostat (PCT) that includes one or both of: a communicating chip capable of talking to Smart Meter (using ZigBee as an example in this invention description but the invention spirit is not limited to ZigBee); and/or a communicating chip capable of talking to internet (can be through the broadband router available in the house or through a cellular connection or through any future communication technologies) (using WiFi as an example for reference in the invention).
[0068] As shown in FIG. 6 , a programmable communicating thermostat may be used with ZigBee and WiFi, in accordance with some embodiments of the present invention. With regard to energy efficiency goals, a consumer may use a PCT with both ZigBee and WiFi interface. The energy use data may be collected from Smart Meter and uploaded to internet based servers using the WiFi Connection. The consumer may access the whole house energy efficiency solution based on energy disaggregation through web and mobile applications.
[0069] With continued reference to FIG. 6 a system in accordance with some embodiments of the present invention may comprise a series of a utility 610 providing electricity or other services to a home 670 . As the energy enters the home 670 , a ZigBee or other HAN 620 may measure the energy provided. A PCT 630 may in communication with the ZigBee 620 , as well as in communication with a web or mobile application 660 that may assist in managing energy usage. The PCT 630 may be connected to the web or mobile application 660 via a WiFi or Ethernet connection to a router 640 , and/or through an internet server or cloud based server 650 .
[0070] Therefore, a demand response signal path from a utility may travel from the utility 610 through the ZigBee 620 to the PCT 630 , thereby enabling modifications of the PCT based upon such demand response. Energy usage data path may be between the ZigBee 620 , PCT 630 , router 640 , internet/cloud 650 , and web or mobile application 660 . The PCT 630 may operate based on information received from the ZigBee 620 and the router 640 .
[0071] With regard to utility demand response concerns, a utility may send a peak demand reduction signal on a peak usage day either using ZigBee or WiFi. The PCT may then cut back the energy usage by reducing the cooling/heating cycles or relax the thermostat set point by a few degrees. Consumers may further program how much cut back they allow based on their personal preferences or on other ambient conditions.
[0072] As illustrated in FIG. 7 , a programmable communicating thermostat may be used with WiFi only, in accordance with some embodiments of the present invention. With regard to energy efficiency goals, the consumer may use a PCT with WiFi interface only. The energy use data may be collected directly from utility servers (sometimes lower resolution and non-real time compared to using a ZigBee). The information transferred from PCT (set points, start and end times and indoor temperature drops with respect to outdoor temperature) helps perform energy disaggregation on the whole house data from utility. The consumer may access the whole house energy efficiency solution based on energy disaggregation through web and mobile applications.
[0073] With continued reference to FIG. 7 a system in accordance with some embodiments of the present invention may comprise a series of a utility 710 providing electricity or other services to a home 770 . As the energy enters the home 770 , a ZigBee or other HAN 720 may measure the energy provided. A PCT 730 may in communication with a web or mobile application 760 that may assist in managing energy usage. The PCT 730 may be connected to the web or mobile application 760 via a WiFi or Ethernet connection to a router 740 , and/or through an internet server or cloud based server 750 .
[0074] With regard to demand response, a utility 710 may send the peak demand reduction signal on the peak demand event day through internet connection to the PCT 730 by way of the internet/cloud 750 and the router 740 . The PCT 730 may reduce the energy usage by reducing the cooling/heating cycles or relax the thermostat set point by a few degrees. A consumer may further program how much cut back they allow based on personal preference or on other ambient conditions.
[0075] (ii) Interaction of Energy Usage Data with PCT.
[0076] This application of energy disaggregation may provide a two-way benefit. For data collected at very low resolution where appliance signatures are not very clear, energy disaggregation becomes harder and loses accuracy. Moreover, there are numerous issues surrounding the use of programmable thermostats. For example, according to some studies, most people never program their thermostat. In addition, even if a PCT is programmed, a consumer's lifestyle is often not as predictable and simple to fit into the time zones made available by existing thermostats (wake up, gone to work, come back, sleep—separate for weekdays and weekends). Moreover, as seasons change, consumer's routines and lifestyles often change—yet again, PCTs are typically not reprogrammed to reflect such changes.
[0077] In accordance with some embodiments of the present invention, one solution to the issues raised above is set forth in FIG. 8 , which sets forth an interaction between energy use data and a user's PCT. Such an interaction between energy disaggregation and PCT may help in solving the issues noted above. With reference to FIG. 8 , a PCT 810 may receive set point, start and end times, and regular temperature drops from a user. Such collections may be used to enhance whole-house energy management. Additional information 830 may be obtained from online or cloud connections. Such information may be used to offer integrated energy efficiency and demand response, as well as create a personalized PCT schedule that may provide user eligibility for higher utility rebates.
[0078] Additional information 830 may be electrical and non-electrical information. For example, weather data 831 may be used to modify PCT settings. Social data 832 —such as information from FaceBook or Twitter—may be used to determine when a user is or is not present (for example, either out for an evening or on a vacation). Direct home data 833 such as square footage, date of construction, etc. may be utilized, as well as training data and/or home specific data that may be captured by a smart meter, green button and/or ZigBee-like device(s).
[0079] This additional information 830 may be used, through some of the embodiments of the present invention discussed above, to contour the PCT schedule to a specific user in a specific home at a specific time of year.
[0080] The PCT may benefit from the energy data analysis. The energy data disaggregation may be used to identify the following characteristics following for any property: (i) “Active Time”—When someone may be inside the property and may be in an active state (not sleeping); (ii) “Passive Time”—When someone may be inside property but may be in a passive state (possibly sleeping), and (iii) Not at Home—When no one may be inside the property.
[0081] To determine the user home status—that is, whether or not a user is home or the home is otherwise “active”—low activity period and high activity period can be detected by comparing the energy consumption and frequency of appliance ON/OFF cycles. When the house is deemed active, appliance traces may assist in identifying human behavior. For example, an identifiable base-load may be due to incidental usage resulting from occupancy—lighting, TV, computer, etc. Moreover, cooking or laundry may be detected, as well as heating and cooling. Similarly, it can be determined that a water heater is operating in a manner indicating usage of hot water, rather than a passive mode.
[0082] When the house is not active periods of inactivity may be compared to the local time. If the passive or not active time continues longer than few days, a determination of vacation status may be made. Accordingly, various reminders and/or notifications may be sent to the consumer. For example, if a vacation status is determined, a notice may be sent to the user reminding the user to lower the thermostat to avoid excess energy usage. Given the proliferation of programmable communicating thermostats, consumers can often modify home settings remotely (for example, through the use of a smart phone or computer connection).
[0083] Once the house schedule is determined, the house schedule may be used to create a custom PCT schedule for the house. This custom schedule may then be automatically downloaded into the PCT. The scheduling may be dynamically updated periodically, for example every day, week or month based on changes in consumer lifestyle detected by energy disaggregation. The creation of custom schedule and auto download tackles the issues described with PCTs earlier in this section.
[0084] The energy disaggregation analysis may benefit from inputs from PCT by continuously collecting information such as, but not limited to: (i) a set point of the PCT; (ii) start/end times for identified temperature cycles; (iii) the ambient indoor temperature; and (iv) consumer intervention of schedule and set points (e.g., when a user lowers the temperature “on the fly,” for example to account for a particularly warm day.
[0085] These parameters may act as important input to the energy disaggregation to make it more accurate, especially in case where the energy data is collected at a lower resolution (example Green button data at one hour interval resolution) and may not contain clear appliance signatures to identify and extract appliance energy use clearly.
[0086] Further, the inputs from PCTs combined with energy data may be used to evaluate the thermal envelope of the building and identify if it is efficient. The amount of energy consumed while the heating or cooling is working to get the home indoor temperature to the set point may assist in estimating the thermal mass of the building and its insulation state. This, when compared to what an efficient house should be, may present a highly personalized recommendations to a user, and can also be used for Measurement and Verification of energy savings for the home by comparing before and after any major retrofit.
[0087] With reference to FIG. 9 , an exemplary algorithm 90 for the interaction of energy usage data and a programmable communicating thermostat will now be discussed. At 905 , data may be collected from a smart meter, and such data may be provided to perform energy analysis at 910 . Such data may be also be used to determine that no one is home (i.e., the house is in a passive or inactive state) at 915 , or to modify or refine a schedule of a PCT.
[0088] If it is determined at 915 that no one is home, then temporary control of the PCT may be obtained at 960 , in order to prevent excess energy usage. If an energy analysis is performed at 910 , then various PCT schedules may be determined. Such schedules may include an “Active Lifestyle” schedule 925 , a “Passive Lifestyle” schedule 930 , and/or a “Not at Home” schedule 935 . These schedules 925 , 930 , 935 may be utilized to form a custom PCT schedule at 940 . If, at this time, it is determined that no one is at home at 915 , then the process may again revert to 960 where temporary control of the PCT is obtained.
[0089] At 945 the custom PCT schedule may be automatically (or manually) downloaded to the PCT. The PCT schedules at 920 may be accordingly refined. During usage, a user may intervene at 950 , at which point the PCT and/or the energy usage data may record the user intervention at 955 , and use such information at 920 to again refine the PCT schedule. Seasonal changes 965 may also be provided as an input in order to refine the PCT schedule.
[0090] In such a manner, the PCT schedule may be continually revised and modified to conform to the actual usage of the user, including vacation times, seasonal changes, etc.
[0091] (iii) Targeted Outreach for Utilities.
[0092] Utilities often run a number of consumer-oriented programs to save energy and reduce peak load. However, the outreach is not typically effective at targeting appropriate consumers, which may result in higher costs and lower customer adoption. Further, such programs often leave consumers confused due to receiving a number of different program-specific messages from their utilities, many of which may be irrelevant or not useful to a particular consumer.
[0093] The energy disaggregation on energy use data collected by utilities for all customers may provide a unique opportunity to efficiently target specific consumers or specific groups of consumers for different programs. For example, a utility with five (5) million users may desire need to implement peak demand reduction in 100,000 homes. In order to obtain participation from 100,000 homes, the utility may typically need to send out approximately one (1) million communications (e.g., flyers, emails, etc.), and often has approximately a 10% customer uptake. With targeted outreach based on energy disaggregation, the number of communications required to obtain 100,000 participants may be reduced to a much lower amount, for example, 500,000, thereby potentially increasing the consumer uptake from 10% to 20%, and accordingly reducing the cost of consumer outreach by hundreds of thousands or even millions of dollars.
[0094] The utility energy use data may be collected by a utility for all consumers (or a subset as required by application) may be aggregated or imported into one database storage system. Similarly, energy disaggregation may be performed on some or all of the data in a utilities's system. For example, such disaggregation may be performed as set forth in one or more of the following references, each owned by the applicant and incorporated by reference in their entirety: U.S. patent application Ser. No. 13/366,850, U.S. Provisional Patent Application 61/638,265—filed Apr. 25, 2012, U.S. Provisional Patent Application 61/542,610—filed Oct. 3, 2011, U.S. Provisional Patent Application 61/485,073—filed May 11, 2011, and U.S. Provisional Patent Application 61/439,826—filed Feb. 4, 2011.
[0095] A custom report for each utility program using energy disaggregation may be created. For example, for targeting peak demand reduction Smart AC program, the report may be created with following rules—find customers who use their Air Conditioners or Heaters during:
i. Day Hours of 12 pm-7:00 pm ii. Days Monday through Friday iii. Temperature>80 degrees Fahrenheit iv. Use greater than a specified amount of kWh per month v. Use greater than a specified amount of kWh in each day on heating/cooling vi. Sort the users by zip codes and peak demand attributed to the use of heating/cooling.
[0102] (iv) Measurement and Verification.
[0103] It may be desirable to provide measurement and/or verification of certain claims, for example promised benefits of utility sponsored programs. In the past, measurement of the savings/benefits—and therefore verification of a claim or promise of such savings/benefits—has been based on a variety of techniques. Generally speaking, very few of these techniques use the energy use data as collected by utilities. However, with the availability of this data, appropriate analysis of energy use data before and after any program may make measurement and verification more accurate, faster and less expensive for utilities.
[0104] The use of energy disaggregation for measurement and verification of a utility sponsored demand response program may be used as an example in the description below. However, this is but one an example. The application of energy disaggregation to measurement and verification of all other programs is similar and contemplated by the present invention.
[0105] Method to perform measurement and verification using energy use data in accordance with some embodiments of the present invention may include: the utility energy use data collected by utility for all consumers (or a subset as required by application) may be aggregated or imported into one database storage system. Similarly, the energy disaggregation may be performed on some or all of the data in the system. For example, such disaggregation may be performed as set forth above.
[0106] In addition, if required, the reduction in energy (kWh) over a short period of time may be correlated to the reduction in the peak demand (kW) for specific appliance category for the house. Similarly, the data may be normalized to remove the fluctuations of weather or other demographic factors. Moreover, the energy use data for a target set of participating homes (where each home needed to sign up and is known) or a participating region (where each house did not need to sign up and could have still participated in the program) may be compared before and after the program. Only the relevant appliance categories may be compared (example, for a Smart AC program, only the heating and cooling categories are compared since other categories do not get affected by the program). Such information may be used to quantify the benefits or the program based on above comparison.
[0107] It will be understood that the specific embodiments of the present invention shown and described herein are exemplary only. Numerous variations, changes, substitutions and equivalents will now occur to those skilled in the art without departing from the spirit and scope of the invention. Accordingly, it is intended that all subject matter described herein and shown in the accompanying drawings be regarded as illustrative only, and not in a limiting sense, and that the scope of the invention will be solely determined by the appended claims.
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Aspects in accordance with embodiments of the invention may include a method for remotely setting, controlling, or modifying settings on a programmable communicating thermostat (PCT) in order to customize settings to a specific house and user, including steps of: receiving at a remote processor information entered into the PCT by the user; receiving at the remote processor: non-electrical information associated with the specific house or user; and energy usage data of the specific house; performing by the remote processor energy disaggregation on the energy usage data; determining by the remote processor a custom schedule for the PCT based upon the information entered by the user, the non-electrical information associated with the specific house or user, and disaggregated energy usage data; revising by the remote processor, the custom schedule for the PCT based upon additional user input or seasonal changes; providing the custom schedule for the PCT to the PCT.
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CROSS REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of U.S. Provisional Application Ser. No. 60/255,629, titled “Variable Displacement Pump and Method,” filed Dec. 12, 2000.
FIELD OF THE INVENTION
This invention relates generally to fluid pumps and more particularly to a variable displacement vane pump.
BACKGROUND OF THE INVENTION
Hydraulic power transmission assemblies and fluid distribution systems may utilize a vane-type pump. Such pumps typically have a rotor with a plurality of circumferentially spaced vanes rotatably carried by the rotor and slidable relative thereto in slots provided in the rotor. The rotor and vanes cooperate with the internal contour of a containment ring or eccentric ring eccentrically mounted relative to an axis of the rotor and vanes to create fluid chambers between the containment ring or eccentric ring, rotor and vanes. Due to the eccentricity between the containment ring or eccentric ring and the rotor and vanes, the fluid chambers change in volume as they are moved with the rotating rotor and become larger in volume as they are moved across an inlet port and smaller in volume across an outlet port. To vary the eccentricity between the containment ring or eccentric ring and the rotor, the containment ring or eccentric ring may be pivoted upon a fixed axis in a pump housing. Pivoting the containment ring or eccentric ring varies the change in volume of the fluid chambers in use of the pump and hence, varies the displacement characteristic of the pump.
Side plates carried by the pump housing enclose the containment ring or eccentric ring, the rotor and the vanes, and provide passages through which fluid flows to and from the rotor and vanes. These passages, along with timing grooves and the containment ring or eccentric ring contour define pump cycles or zones, namely a fill or inlet zone, a precompression zone from the inlet to the outlet, a displacement or discharge zone, and a decompression zone from the outlet to the inlet.
In current vane-type pumps, the containment ring or eccentric ring is pivoted and oriented by a fluid pressure signal applied to a piston or directly to the containment ring which pivots the containment ring or eccentric ring against the bias of a fixed spring. In other words, a single fluid pressure signal is used to pivot the containment ring or eccentric ring. Accordingly, the control of the containment ring or eccentric ring is essentially limited to a pressure relief type control wherein the containment ring or eccentric ring is pivoted against the bias of the spring only when a sufficient pressure is applied to the piston or containment ring or eccentric ring. When the fluid pressure applied to the piston is not sufficient to move the containment ring or eccentric ring against the bias of a fixed spring, the position of the containment ring or eccentric ring is determined by the spring which limits to one regulation profile characteristic.
Additionally, it has been recognized that for efficient and quiet operation of a vane-type pump it is desirable to maintain the vanes in continuous contact with the containment ring or eccentric ring. Some vane-type pumps depend upon centrifugal force to maintain the contact between the vanes and the containment ring or eccentric ring. These pumps may lack positive and continuous contact between the vane and containment ring or eccentric ring resulting in adverse wear and decreased pump performance. One method to improve the contact between the vanes and the containment ring or eccentric ring involves applying a discharge fluid pressure to chambers or slots in the rotor in which the vanes are received. The fluid pressure drives the vanes radially outwardly and into contact with the containment ring or eccentric ring. However, in at least some conditions, the vanes have a tendency to remain in the rotor slots and the centrifugal force of the spinning rotor is not sufficient to overcome the viscous drag force on the vanes. Without the vanes extending radially outwardly from the rotor, the rotating rotor displaces little if any fluid such that there is little or no discharge pressure. Accordingly, there is little or no discharge pressure communicated to the vane slots and tending to force the vanes radially outwardly from the rotor. Hence, the pump will not prime.
SUMMARY OF THE INVENTION
A variable displacement vane-type fluid pump is provided which has a regulated discharge controlled at least in part by a pair of pilot pressure signals. Desirably, the vane pump of the invention permits improved regulation of the pump discharge such that the pump can meet the various requirements of lubrication for internal combustion engines at all speeds. Of course, the vane pump may also be utilized in power transmission and other fluid distribution applications. The variable displacement vane pump of the invention may utilize both hydrostatic and mechanical assistance in radially positioning its vanes to ensure efficient and quiet operation of the pump and to facilitate priming of the pump. The vane pump of the invention may also use both hydrostatic and mechanical actuators to control the position of its containment ring or eccentric ring and hence, regulate the output of the pump. According to yet another aspect of the present invention, to prevent inlet flow restriction or cavitation, a valve may be provided to permit some of the pump outlet or discharge flow to exhaust into the pump inlet to provide needed velocity energy to the fluid flow in the pump inlet.
To achieve the dual pilot pressure regulation of the pump output the vane pump has a pair of actuators each operable to position the containment ring or eccentric ring as desired. In one embodiment of the invention, the actuators are opposed pistons that are each actuated by a separate pilot pressure signal to pivot the cam as a function of the pressure signals. In another embodiment, a seal may be provided between the containment ring or eccentric ring and the pump housing defining separate chambers, the chambers receive pressurized fluid bearing directly on the containment ring or eccentric ring to position it and function as the actuators without any pistons between the fluid signal and the containment ring or eccentric ring. In any of the embodiments, the cam may be biased in one or both directions of its pivotal movement, such as by one or more springs.
To ensure priming of the pump and development of discharge pressure, one or more rings lie adjacent to the rotor radially inwardly of the vanes to ensure that at least some of the vanes extend radially outwardly beyond the rotor and in contact with the contoured ring at all times. Preferably, hydrostatic pressure is employed in chambers behind the vanes to provide full extension of the vanes and maintain them in continuous contact with the containment ring or eccentric ring.
Accordingly, some of the objects, features and advantages of this invention include providing an eccentric vane pump which enables improved control of the pump discharge, ensures priming of the pump, reduces inlet flow restriction and cavitation, enables pressure signals from two or more points in the hydraulic circuit to be used to regulate pump discharge, strategically positions the cam and its pivot to minimize movement in the direction perpendicular to the desired direction of movement of the eccentric ring as it pivots, is of relatively simple design and economical manufacture and assembly, is durable, reliable and has a long and useful life in service.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other objects, features and advantages of this invention will be apparent from the following detailed description of the preferred embodiments, appending claims and accompanying drawings in which:
FIG. 1 is a perspective view of a variable displacement eccentric vane pump according to the present invention;
FIG. 2 is a perspective view of the vane pump of FIG. 1 with a side plate removed to show the internal components of the pump;
FIG. 3 is a plan view of the pump as in FIG. 2 illustrating the containment ring or eccentric ring in its zero-displacement position;
FIG. 4 is a plan view of the pump as in FIG. 2 illustrating the containment ring or eccentric ring in its maximum-displacement position;
FIG. 5 is a diagrammatic sectional view of a variable target dual pilot regulation valve which pivots the containment ring or eccentric ring of the pump according to one aspect of the present invention;
FIG. 6 is an enlarged, fragmentary sectional view illustrating a portion of the rotor and a vane according to the present invention;
FIG. 7 is an enlarged, fragmentary sectional view of the rotor and vane illustrating a seal between the vane and rotor when the vane is tilted within its slot in the rotor;
FIG. 8 is a schematic representation of the hydraulic circuit of the vane pump of an embodiment of this invention including completing a 3-way variable target dual pilot regulation valve;
FIG. 9 is a schematic representation of the hydraulic circuit of a vane pump according to the present invention including a 3-way regulation valve and an anti-cavitation valve; and
FIG. 10 is a diagrammatic view of the containment ring or eccentric ring of the vane pump in its zero-displacement and maximum-displacement positions.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring in more detail to the drawings, FIGS. 1-3 illustrate a variable displacement vane pump 10 having a rotor 12 and associated vanes 14 driven for rotation to draw fluid through a pump inlet 16 , increase the pressure of the fluid, and discharge the fluid under pressure from an outlet 18 of the pump 10 . A containment ring or eccentric ring 20 is carried by a housing 22 of the pump 10 and is pivoted relative to the rotor 12 to vary the displacement of the pump. Such a pump 10 is widely used in a plurality of fluid applications including engine lubrication and power transmission applications.
The housing 22 preferably comprises a central body 24 defining an internal chamber 26 in which the containment ring or eccentric ring 20 and rotor 12 are received. The housing 22 further includes a pair of end plates 28 , 30 on opposed, flat sides of the central body 24 to enclose the chamber 26 . A groove 32 formed in an internal surface 34 of the central body 24 is constructed to receive a pivot pin 36 between the containment ring or eccentric ring 20 and housing 22 to permit and control pivotal movement of the containment ring or eccentric ring 20 relative to the housing 22 . Spaced from the groove 32 and preferably at a generally diametrically opposed location, a seat surface 38 is provided in the central body 24 . The seat surface 38 is engageable with the containment ring or eccentric ring 20 in at least certain positions of the containment ring or eccentric ring to provide a fluid tight seal between them. One or both of the containment ring or eccentric ring 20 and central body 24 may carry an elastomeric or other type seal 40 that defines at least in part the seat surface.
The containment ring or eccentric ring 20 is annular having an opening 41 and is received within the chamber 26 of the housing 22 . The containment ring or eccentric ring 20 has a groove 42 in its exterior surface which receives in part the pivot pin 36 to permit pivotal movement between the containment ring or eccentric ring 20 and central body 24 . Such pivotal movement of the containment ring or eccentric ring 20 is limited by engagement of the exterior surface of the containment ring or eccentric ring 20 with the interior surface 34 of the central body 24 . As viewed in FIGS. 4 and 10 , the containment ring or eccentric ring 20 is pivoted counterclockwise into engagement with the housing 22 in its first position wherein the pump 10 has its maximum displacement. As best shown in FIGS. 3 and 10 , the containment ring or eccentric ring 20 may be pivoted clockwise from its first position to a second position in which the pump 10 has its minimum displacement. Of course, the containment ring or eccentric ring 20 may be operated in any orientation between and including its first and second positions to vary the displacement of the pump, as desired. The containment ring or eccentric ring 20 has an internal surface which is generally circular, but may be contoured or off-centered to improve or alter the pump 10 performance. The containment ring or eccentric ring 20 may also have a second groove 44 in its exterior surface adapted to carry the seal 40 engageable with the internal surface 34 of the central body 24 to provide a fluid tight seal between the containment ring or eccentric ring 20 and central body 24 . The fluid tight seal essentially separates the chamber 26 into two portions 26 a , 26 b on either side of the seal to enable a pressure differential to be generated between the separated chamber portions 26 a , 26 b . The pressure differential may be used to pivot the containment ring or eccentric ring 20 between or to its first and second positions to control the pump displacement.
To move fluid through the pump 10 , a rotating displacement group 50 is provided in the housing 22 . The rotating displacement group 50 comprises a central drive shaft 52 , the rotor 12 which is carried and driven for rotation by the drive shaft 52 , and a plurality of vanes 14 slidably carried by the rotor 12 for co-rotation with the rotor 12 . The drive shaft 52 is fixed in position for rotation about its own axis 53 . The rotor 12 is fixed to the drive shaft 52 for co-rotation therewith about the axis of the shaft 52 .
As shown, the rotor 12 is a generally cylindrical member having a plurality of circumferentially spaced apart and axially and radially extending slots 54 that are open to an exterior surface 56 of the rotor 12 and which terminate inwardly of the exterior surface 56 . Each slot 54 is constructed to slidably receive a separate vane 14 so that the vanes are movable relative to the rotor 12 between retracted and extended positions. Each slot 54 in the rotor 12 preferably terminates at a small chamber 58 constructed to receive pressurized fluid. The pressurized fluid in a chamber 58 acts on the vane 14 in the associated slot 54 to cause the vane 14 to slide radially outwardly until it engages the internal surface 34 of the containment ring or eccentric ring 20 . Preferably, during operation of the pump 10 , the fluid pressure within the chamber 58 and slot 54 is sufficient to maintain substantially continuous contact between the vanes 14 and the internal surface of the containment ring or eccentric ring 20 .
In accordance with one aspect of the present invention, a vane extension member 60 is movably positioned on the rotor 12 to engage one or more of the vanes 14 and cause such vanes 14 to extend radially outwardly beyond the periphery of the rotor 12 . This facilitates priming the pump 10 by ensuring that at least two of the vanes 14 extend beyond the periphery of the rotor 12 at all times. Without the extension member 60 the vanes 14 may tend to remain in their retracted position, not extending beyond the exterior 56 of the rotor 12 , such that subsequent turning of the rotor 12 without any vanes 14 extending outwardly therefrom, does not displace sufficient fluid to prime the pump 10 and increase the pump output pressure. Accordingly, no fluid pressure is generated in the chambers 58 or slots 54 of the rotor 12 and therefore no pressure acts on the vanes 14 causing them to extend outwardly and the pump 10 will not prime. Such a condition may be encountered, for example, in mobile and automotive applications when starting a cold vehicle in cold weather such as during a cold start of an automobile.
In the embodiment shown in FIG. 2 , the vane extension member 60 is a ring slidably received in an annular recess 62 formed in an end face of the rotor 12 and having a diameter sufficient to ensure that at least two of the vanes 14 extends beyond the periphery of the rotor 12 at all times. The recess 62 provides an outer shoulder 64 and an inner shoulder 66 between which the ring 60 may slide. The ring 60 slides in the recess 62 when acted on by vanes 14 which are radially inwardly displaced via engagement with the containment ring or eccentric ring 20 thereby pushing the ring 60 towards the diametrically opposed vanes 14 causing them to extend beyond the periphery of the rotor 12 . The ring 60 is retained between the rotor 12 and the adjacent side plate of the housing 22 in assembly of the pump 10 . A second ring may be provided on the opposite face of the rotor, if desired.
Desirably, as shown in FIGS. 6 and 7 , the slots 54 in the rotor 12 are sized to permit a fluid film to form on the leading and trailing faces 68 , 69 of each vane 14 . The fluid film supports the vanes 14 as the rotor 12 rotates. The fluid film prevents a wear of the fluid slot effectively seating a bearing surface. Additionally, the size of the slots 54 is desired to prevent vane tilt while still slowing fluid to enter a contact seal between the rotor 12 and vanes 14 in the areas of their contact should vane tilting occur, to the extent that any vane tilting is present. The contact seals maintain the pressurized fluid acting on the vanes 14 and prevents it from leaking or flowing out of the slots 54 . Such leakage is otherwise likely to occur due to the pressure differential between the fluid in the chambers 58 and slots 54 which is at pump outlet pressure and lower pressure portions of the pump cycle (nearly all but at the outlet of the pump). By preventing this leakage, it is ensured that a sufficient hydrostatic force biases the vanes 14 radially outwardly toward the containment ring or eccentric ring 20 to improve the continuity of the contact between the vanes 14 and the containment ring or eccentric ring 20 .
To displace fluid, the containment ring or eccentric ring 20 is mounted eccentrically relative to the drive shaft 52 and rotor 12 . This eccentricity creates a varying clearance or gap between the containment ring or eccentric ring 20 and the rotor 12 . The varying clearing creates fluid pumping chambers 70 , between adjacent vanes 14 , the rotor 12 and the internal surface of the containment ring or eccentric ring 20 , which have a variable volume as they are rotated in use. Specifically, each pumping chamber 70 increases in volume during a portion of its rotational movement, thereby creating a drop in pressure in that pumping chamber 70 tending to draw fluid therein. After reaching a maximum volume, each pumping chamber 70 then begins to decrease in volume increasing the pressure therein until the pumping chamber is registered with an outlet and fluid is forced through said outlet at the discharge pressure of the pump 10 . Thus, the eccentricity provides enlarging and decreasing pumping chambers 70 which provide both a decreased pressure to draw fluid in through the inlet of the pump 10 and thereafter increase the pressure of the fluid and discharge it from the outlet of the pump 10 under pressure.
The degree of the eccentricity determines the operational characteristics of the pump 10 , with more eccentricity providing higher flow rate of the fluid through the pump 10 and less eccentricity providing a lower flow rate in pressure of the fluid. In a so-called “zero displacement position” or the second position of the containment ring or eccentric ring 20 shown in FIG. 3 , the opening 41 is essentially coaxially aligned with the rotor 12 so that the fluid pumping chambers 70 have an essentially constant volume throughout their rotation. In this orientation, the pumping chambers 70 do not enlarge to draw flow therein nor do they become smaller in volume to increase the pressure of fluid therein creating a minimum performance condition or a zero displacement condition of the pump 10 . When the containment ring or eccentric ring 20 is in its first or maximum displacement position the pumping chambers 70 vary in size between their maximum volume and minimum volume as the rotor 12 rotates providing increased pump displacement.
As shown in FIGS. 3 and 4 , to control the pivoting and location of the containment ring or eccentric ring 20 a pair of pistons 72 , 74 may be utilized with the pistons 72 , 74 operable in opposed directions to pivot the containment ring or eccentric ring 20 between its first and second positions. Desirably, each piston 72 , 74 may be responsive to different fluid pressure signals that may be taken from two different points in the fluid circuit, one of which must come from the regulating valve. Accordingly, two different portions of the fluid circuit may be used to control the displacement of the containment ring or eccentric ring 20 , and hence the operation and displacement of the pump 10 . The pistons 72 , 74 may be of different sizes as desired to vary the force on the pistons from the pressurized fluid signals. Further, one or both of the pistons 72 , 74 may be a spool type valve biased by a spring, or other mechanism to aid in controlling the movement of the containment ring or eccentric ring 20 and operation of the pump. As an alternative, if a seal 40 is provided between the containment ring or eccentric ring 20 and housing 22 , a controlled volume of fluid under pressure may be disposed directly in the chamber portions 26 a , 26 b defined on opposite sides of the seal 40 . Fluid at different volumes and pressures may be provided on either side of the seal 40 to control the movement of the containment ring or eccentric ring 20 . Of course, any combination of these actuators may be used to control the movement and position of the containment ring or eccentric ring 20 in use of the pump 10 .
Desirably, as best shown in FIG. 10 , in accordance with a further aspect of the present invention, the axis 76 about which the containment ring or eccentric ring 20 is pivoted is located to provide an essentially linear movement of the containment ring or eccentric ring 20 between its first and second positions. To do so, the containment ring or eccentric ring 20 is pivoted about an axis 76 which is offset from the drive shaft axis 53 by one-half of the distance of travel in the direction of eccentricity of the containment ring or eccentric ring 20 between its first and second positions. In other words, the pivot axis 76 of the containment ring or eccentric ring 20 is offset from the drive shaft axis 53 by one-half of the maximum eccentricity of the containment ring or eccentric ring 20 relative to the drive shaft axis 53 , and hence, relative to the rotor 12 . The pivoting movement of the containment ring or eccentric ring 20 occurs along an at least somewhat arcuate path. By positioning the pivot axis 76 of the containment ring or eccentric ring 20 as described, the path of movement of the containment ring or eccentric ring 20 becomes essentially linear between its first and second positions. Non-linear or compound movement of the containment ring or eccentric ring 20 affects the gap or clearance between the rotor 12 and the containment ring or eccentric ring 20 . The performance and operating characteristics of the pump 10 are influenced by this gap or clearance. Accordingly, the non-linear movement of the containment ring or eccentric ring 20 when it is pivoted can vary the size of the fluid chambers throughout the pump 10 , and importantly, in the area of the inlet 16 and outlet 18 of the pump. For example, the pumping chambers 70 may become slightly larger in volume as they approach the outlet 18 reducing the pressure of fluid therein and causing inefficient pressurization of the fluid at the discharge port. Desirably, offsetting the pivot axis 76 of the containment ring or eccentric ring 20 in accordance with this invention provides a movement of the containment ring or eccentric ring 20 which reduces such centrality errors and facilitates control of the pump operating characteristics to improve pump performance and efficiency. The arrangement of the invention also permits a more simple pump design with a center point of the containment ring or eccentric ring opening 41 moving along an essentially linear path. Further, the pump 10 should operate with less airborne or fluid borne noise.
Preferably, to control the application of fluid pressure signals to the actuators that in turn control the movement of the containment ring or eccentric ring 20 , a single control valve 80 reacts to two pilot pressure signals and their application to the actuators. As shown in FIG. 5 , the control valve 80 has a spool portion 82 with a plurality of annular grooves and lands between adjacent grooves providing sealing engagement with a bore 84 in which the spool portion 82 is received. The valve 80 also has a piston portion 86 comprising an outer sleeve 88 and an inner piston 90 slidably carried by the sleeve 88 . A first spring 92 is disposed between the plunger 90 and the spool portion 82 to yieldably bias the position of the spool portion 82 and a second spring 94 is disposed between the sleeve 88 and the plunger 90 to yieldably bias the plunger 90 away from the sleeve 88 .
As shown in FIGS. 5 and 8 , the valve 80 has a first inlet 96 through which fluid discharged from the pump 10 is communicated with a chamber 98 in which the plunger 90 is received to provide a force acting on the plunger 90 in a direction opposing the biasing force of the second spring 94 . A second inlet 100 communicates fluid discharged from the pump 10 with the spool portion 82 . A third inlet 102 communicates fluid pressure from a downstream fluid circuit source from a second portion of the fluid circuit with a chamber 104 defined between the plunger 90 and outer sleeve 88 . A fourth inlet 106 communicates the second portion of the fluid circuit with an end 108 of the spool portion 82 located opposite the plunger 90 . In addition to the inlets, the valve 80 has a first outlet 110 communicating with a sump or reservoir 112 , a second outlet 114 communicating with the first actuator 74 , and a third outlet 116 communicating with the second actuator 72 . As discussed above, the first and second actuators 72 , 74 control movement of the containment ring or eccentric ring 20 to vary the displacement of the pump 10 .
In more detail, the plunger 90 has a cylindrical body 120 with a blind bore 122 therein to receive and retain one end of the first spring 92 . An enlarged head 124 at one end of the plunger 90 is closely slidably received in the chamber 98 , which may be formed in, for example, the pump housing 22 , and is constructed to engage the outer sleeve 88 to limit movement of the plunger 90 in that direction. The outer sleeve 88 is preferably press-fit or otherwise fixed against movement in the chamber 98 . The outer sleeve 88 has a bore 126 which slidably receives the body 120 of the plunger 90 , a radially inwardly extending rim 128 at one end to limit movement of the spool portion 82 toward the plunger 90 , and a reduced diameter opposite end 130 defining the annular chamber 104 in which the second spring 94 is received. The annular chamber 104 may also receive fluid under pressure which acts on the plunger 90 .
The spool portion 82 is generally cylindrical and is received in the bore 84 of a body, such as the pump housing 22 . The spool portion 82 has a blind bore 132 , is open at one end 134 and is closed at its other end 108 . A first recess 136 in the exterior of the spool portion 82 leads to one or more passages 139 which open into the blind bore 132 . The first recess 136 is selectively aligned with the third outlet 116 to permit the controlled volume of pressurized fluid, keeping the displacement high at the second actuator 72 (chamber 26 a ) to vent back through the spool portion 82 via the first recess 136 , corresponding passages 139 blind bore 132 and the first outlet 110 leading to the sump or reservoir 112 . This reduces the volume and pressure of fluid at the second actuator 72 (chamber 26 a ). Likewise, the spool portion 82 has a second recess 140 which leads to corresponding passages 142 opening into the blind bore 132 and which is selectively alignable with the second outlet 114 to permit fluid controlled volume of pressurized fluid, keeping the displacement low at the first actuator 74 (chamber 26 b ) to vent back through the valve 80 via the second recess 140 , corresponding passages 142 , blind bore 132 and first outlet 110 to the sump or reservoir 112 .
The spool portion 82 also has a third recess 144 disposed between the first and second recesses 136 , 140 and generally aligned with the second inlet 100 . The third recess 144 has an axial length greater than the distance between the second inlet 100 and the second outlet 114 and greater than the distance between the second inlet 100 and the third outlet 116 . Accordingly, when the spool portion 82 is sufficiently displaced toward the plunger portion 86 , the third recess 144 communicates the second outlet 114 with the second inlet 100 to enable fluid at discharge pressure to flow through the second outlet 114 from the second inlet 100 . This increases the volume and pressure of fluid acting on the first actuator 74 . Likewise, when the spool portion 82 is displaced sufficiently away from the plunger portion 86 , the third recess 144 communicates the second inlet 100 with the third outlet 116 to permit fluid at pump discharge pressure to flow through the third outlet 116 from the second inlet 100 . This increases volume and pressure of fluid acting on the second actuator 72 . From the above it can be seen that displacement of the spool portion 82 controls venting of the displacement control chamber through the first and second recesses 136 , 140 , respectively, when they are aligned with the second and third outlets 114 , 116 , respectively. Displacement of the spool portion 82 also permits charging or increasing of the pilot pressure signals through the third recess 144 when it is aligned with the second and third outlets 114 , 116 , respectively.
Desirably, the displacement of the spool portion 82 may be controlled at least in part by two separate fluid signals from two separate portions of the fluid circuit. As shown, fluid at pump discharge pressure is provided to chamber 98 so that it is applied to the head 124 of the plunger 90 and tends to displace the plunger 90 toward the spool portion 82 . This provides a force (transmitted through the first spring 92 ) tending to displace the spool portion 82 . This force is countered, at least in part, by the second spring 94 and the fluid pressure signal from a second point in the fluid circuit which is applied to the distal end 108 of the spool portion 82 and to the chamber 104 between the outer sleeve 88 and plunger 90 which acts on the head 124 of the plunger 90 in a direction tending to separate the plunger from the outer sleeve. The movement of the spool portion 82 can be controlled as desired by choosing appropriate springs 92 , 94 , fluid pressure signals and/or relative surface areas of the plunger head 124 and spool portion end 108 upon which the pressure signals act. Desirably, to facilitate calibration of the valve 80 , the second spring 94 may be selected to control the initial or at rest compression of the first spring 92 to control the force it applies to the spool portion 82 and plunger 90 .
In response to these various forces provided by the springs 92 , 94 and the fluid pressure signals acting on the plunger 90 and the spool portion 82 , the spool portion 82 is moved to register desired recesses with desired inlet or outlet ports to control the flow of fluid to and from the first and second actuators 72 , 74 (or chamber 26 a / 26 b ). More specifically, as viewed in FIG. 5 , when the spool portion 82 is driven downwardly, the third recess 144 bridges the gap between the second inlet 100 and the third outlet 116 so that pressurized fluid discharged from the pump 10 is provided to the second actuator 72 . This movement of the spool portion 82 preferably also aligns the second recess 140 with the second outlet 114 to vent the volume and pressure of fluid at the first actuator 74 to the sump or reservoir 112 . Accordingly, the containment ring or eccentric ring 20 will be displaced by the second actuator 72 toward its first position increasing the displacement of the pump 10 . The spool 82 operates with the bore 84 and outlets to behave as what is commonly known as a “4-way directional valve.” As the spool portion 82 is driven upwardly, as viewed in FIG. 5 , the third recess 144 will bridge the gap between the second inlet 100 and the second outlet 114 providing fluid at pump discharge pressure to the first actuator 74 . This movement of the spool portion 82 preferably also aligns the first recess 136 with the third outlet 116 to vent the volume of and pressure of fluid at the second actuator 72 to the sump or reservoir 112 . Accordingly, the containment ring or eccentric ring 20 will be moved toward its second position decreasing the displacement of the pump 10 . In this manner, the relative controlled volume and pressures are controlled by two separate pressure signals which may be taken from two different portions of the fluid circuit. In the embodiment shown, a first pressure signal is the fluid discharged from the pump 10 and a second pressure signal is from a downstream fluid circuit source. In this manner, the efficiency and performance of the pump can be improved through more capable control.
As best shown in FIG. 9 , an inlet flow valve 150 in the fluid circuit may be provided to selectively permit fluid at pump discharge pressure to flow back into the pump inlet 16 when the pump 10 is operating at speeds wherein atmospheric pressure is insufficient to fill the inlet port 16 of the pump 10 with fluid. This reduces cavitation and overcomes any restriction of fluid flow to the inlet 16 of the pump 10 or any lack of fluid potential energy. To accomplish this, the inlet flow valve 150 may be a spool type valve slidably received in a bore 152 of a body, such as the pump housing 22 , so that it is in communication with the fluid discharged from the pump outlet 18 . As shown, the fluid circuit comprises the pump 10 , with the pump outlet 18 leading to an engine lubrication circuit 154 through a supply passage 156 which is connected to the bore 152 containing the inlet flow valve 150 . Downstream of the engine lubrication circuit 154 , fluid is returned to a reservoir 112 with a portion of such fluid routed through a pilot fluid passage 158 leading to the inlet flow valve 150 to provide a pilot pressure signal on the inlet flow valve 150 , if desired. A spring 159 may also be provided to bias the inlet flow valve 150 . From the reservoir, fluid is supplied through an inlet passage 160 to the inlet 16 of the fuel pump 10 . The inlet passage 160 can pass through the bore 152 containing the inlet flow valve 150 and is separated from the supply passage 156 by a land 162 of the inlet flow valve 150 which provides an essentially fluid tight seal with the body.
Accordingly, the fluid discharged from the pump 10 acts on the land 162 by way of passage 156 in communication with from outlet line 157 and tends to displace the inlet flow valve 150 in a direction opposed by the spring 159 and the pilot pressure signal applied to the inlet flow valve 150 through the pilot fluid passage 158 . When the pressure of fluid discharged from the pump 10 is high enough, to overcome the spring and pilot pressure from passage 158 , the inlet flow valve 150 will be displaced so that its land 162 will be moved far enough to open the inlet passage 160 permitting communication between the supply passage 156 and inlet passage 160 through the bore 152 and passage 161 , as shown in FIG. 9 . Thus, a portion of the fluid discharged from the pump 10 is fed back into the inlet 16 of the pump 10 along with fluid supplied from the reservoir 112 for the reasons stated above. This aspirated flow of pressurized fluid into the inlet 16 supercharges the pump inlet to ensure that the pump 10 is pumping liquid and not air or gas. This prevents cavitation and improves the pump efficiency and performance.
The purpose of the valve 150 and its supercharging effect is to convert available pressure energy into velocity energy at the inlet to provide supercharging.
Accordingly, the pump 10 incorporates many features which facilitate the design and operation of the pump, enable vastly improved control over the pump operating parameters and output, and improve overall pump performance and efficiency. Desirably, the vane pump of the invention can meet the various requirements of lubrication for internal combustion engines at all speeds. Of course, the vane pump may also be utilized in power transmission and other fluid distribution applications.
Finally, while preferred embodiments of the invention have been described in some detail herein, the scope of the invention is defined by the claims which follow. Modifications of and applications for the inventive pump which are entirely within the spirit and scope of the invention will be readily apparent to those skilled in the art.
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A variable displacement vane-type fluid pump is provided which permits improved regulation of the pump discharge such that the pump can meet the various requirements of lubrication for internal combustion engines at all speeds with minimized use of power. Of course, the vane pump may also be utilized in a wide range of power transmission and other fluid distribution applications. The variable displacement vane pump of the invention may utilize both hydrostatic and mechanical assistance in radially positioning its vanes to ensure efficient and quiet operation of the pump and to facilitate priming of the pump. The vane pump of the invention may also use both hydrostatic and mechanical actuators to control the position of its containment ring or eccentric ring and hence, regulate the output of the pump. According to yet another aspect of the present invention, to prevent inlet flow restriction or cavitation, a valve may be provided to permit some of the pump outlet or discharge flow to bleed into the pump inlet to provide needed velocity and energy to the fluid flow into the pump inlet.
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FIELD OF THE INVENTION
[0001] The present invention relates to methods for differentiating stem cells into insulin-producing cells by culturing such cells in specially defined mediums and optimally, activating one or more genes involved in beta-cell differentiation. The present invention provides means for treatment of pancreatic diseases, metabolic syndrome and metabolic disorders with impaired glucose levels, for instance, but not limited to, diabetes mellitus, hyperglycaemia and impaired glucose tolerance, by transplanting said insulin-producing cells into diabetic animals and humans. The methods can further be used to generate cells for the identification and characterisation of compounds which stimulate beta-cell differentiation, insulin secretion or glucose responsiveness. Differentiated insulin-producing cells can also be used to study the toxic and other effects of exogenous compounds on beta-cell function.
BACKGROUND OF THE INVENTION
[0002] Diabetes, hyperglycaemia and impaired glucose tolerance are endocrine disorders characterised by inadequate production or use of insulin, which affects the metabolism of carbohydrates, proteins, and lipids resulting in abnormal levels of glucose in the blood. Diabetes is a heterogeneous disease that can be classified into two major group: Type 1 diabetes (also known as Insulin-dependent diabetes, IDDM, type I, juvenile diabetes) and Type 2 diabetes (Noninsulin-dependent diabetes, NIDDM, type II, maturity-onset diabetes).
[0003] The functional unit of the endocrine pancreas is the islet of Langerhans which are scattered throughout the exocrine portion of the pancreas and are composed of four cell types: alpha-, beta-, delta-, and PP-cells. Beta-cells produce insulin, represent the majority of the endocrine cells and form the core of the islets while alpha-cells secrete glucagon and are located in the periphery. Delta-cells and PP-cells are less numerous and secrete somatostatin and a pancreatic polypeptide respectively. Insulin and glucagon are key regulators of blood glucose levels. Insulin lowers blood glucose levels by increasing its cellular uptake and conversion into glycogen. Glucagon elevates blood glucose levels by intervening in the breakdown of liver glycogen. Type 1 diabetes is characterised by an autoimmune destruction of insulin-producing beta-cells. Type 2 diabetes is characterised by insulin resistance and impaired glucose tolerance where insulin is not efficiently used or is produced in insufficient amounts by the beta-cells. Therefore, type 2 patients often require additional insulin to regulate blood glucose levels. Consequently, there is little therapeutic difference in the administration of insulin between type 1 and type 2 diabetic patients (see Fajans in Diabetes Milletus fifth editions; Porte and Sherwin, ed; Appleton & Lange pub. 1997, 1423 pp). Individuals afflicted with diabetes must inject themselves up to six times a day with insulin.
[0004] Despite insulin injections, diabetic patients develop complications and their susceptibility to strokes, blindness, amputations, kidney and cardiovascular diseases is greatly increased while their life expectancy is shortened (Nathan (1993) N. Engl. J. Med. 328:1676-1685; Group, T. D. C. a. C. T. R. (1993) N. Engl. J. Med. 329:977-986). Replacement of absent insulin-producing cells by transplantation of islets of Langerhans or insulin-producing cells is one promising therapeutic option (Luzi et al. (1996) J. Clin. Invest. 97:2611-2618; Bretzel et al. (1996) Ther. Umsch. 53:889-901) However, the availability of human donor tissue for transplantation is severely limited. An alternative option would be the use of animal tissues from pigs but serious technical problems such as long term immunosuppression and the risk of transferring a porcine pathogen such as porcine endogenous retrovirus into the human population must be solved (Butler et al. (1998) Nature 391:320-324; Bach et al. (1998) Nature Med. 4:141-144; Shapiro et al. (2000) N. Engl. J. Med. 343:230-238). One solution to this problem would be to generate a human “surrogate cell” capable of assuming the functions of the missing or malfunctioning beta-cell. Therefore, there exists a need for producing an unlimited amount of surrogate insulin-producing cells for transplantation into diabetic patients. The present invention satisfies this need by providing an easy method for inducing the differentiation of stem cells into functional insulin-producing cells.
[0005] Stem cells are undifferentiated or immature cells that can give rise to various specialised cell types. Once differentiated or induced to differentiate, stem cells can be used to repair damaged and malfunctioning organs. Stem cells can be of embryonic or adult origin. Adult or somatic stem cells have been identified in numerous different tissues such as muscle, bone marrow, liver, and brain (Vescovi and Snyder (1999) Brain Pathol., 9:569-598; Seale and Rudnicki (2000) Dev. Biol., 218:115-124). In the pancreas, several indications suggest that stem cells are also present within the adult tissue (Gu and Sarvetnick (1993) Development, 118:33-46; Bouwens (1998) Microsc Res Tech, 43:332-336; Bonner-Weir (2000) J. Mol. Endocr., 24:297-302). However, this population is poorly defined and represents a very small percentage of cells in the pancreas.
[0006] Embryonic stem cells can be isolated from the inner cell mass of pre-implantation embryos (ES cells) or from the primordial germ cells found in the genital ridges of post-implanted embryos (EG cells). When grown in special culture conditions such as spinner culture or hanging drops, both ES and EG cells aggregate to form embryoid bodies (EB). EBs are composed of various cell types similar to those present during embryogenesis. When cultured in appropriate media, EB can be used to generate in vitro differentiated phenotypes, such as extraembryonic endoderm, hematopoietic cells, neurons, cardiomyocytes, skeletal muscle cells, and vascular cells. No method has been described so far that allows EB to efficiently differentiate into insulin-producing cells.
[0007] Soria and colleagues describe a method for selecting insulin-secreting cell clones from ES cells using a cell-trapping system, wherein cells are transfected with a plasmid allowing the expression of neomycin resistance gene under the control of the regulatory region of the human insulin gene. Cells from an insulin-secreting cell clone were implanted in the spleen of diabetic mice. The implanted cells can normalise blood glucose levels and restore body weight in the treated animals (Soria et al. (2000) Diabetes 49:157-162). A disadvantage of this selection method is, however, its low efficiency.
[0008] Lumelsky and colleagues (Lumelsky et al. (May 2001), Science 292: 1389-1394) have generated insulin-expressing cells from mouse ES cells. ES cells are expanded on a gelatine-coated tissue culture surface without feeder cells and in the presence of LIF. Then, embryoid bodies are generated in suspension in ES cell medium in the absence of LIF. In a further stage nestin-positive cells are selected in a serum-free medium (ITSFn) on tissue culture surface. Resulting pancreatic endocrine progenitor cells are expanded and the differentiation and morphogenesis of insulin-secreting islet clusters is induced. However, the insulin-secreting islet clusters did not restore normal blood glucose levels when transplanted into diabetic mice.
[0009] Assady et al. (August 2001), Diabetes, 50:1-7) describe a spontaneous in vitro differentiation of pluripotent human embryonic stem cells into cells having the characteristics of insulin-producing cells. Secretion of insulin into the medium was observed in a differentiation-dependent manner and was associated with the appearance of other β-cell markers. However, the efficiency of differentiation was low with only 1-3% of differentiated cells positive for insulin.
[0010] The present invention is aimed at inducing the differentiation of ES cells by activation of specific genes into insulin-producing cells and is therefore different from the methods of the prior art designed to select such cells.
[0011] In recent years, several genes have been shown to be essential for the generation of pancreatic endocrine cells during embryogenesis (Edlund (1998) Diabetes, 47:1817-1823; St-Onge et al. (1999) Curr. Opin. Genet. Dev., 9:295-300). Pancreas development involves a series of inductive signals emanating from the surrounding mesodermic tissues and transcription factors expressed in the pancreatic epithelium. The homeobox containing transcription factor Pdx1 (also referred to Idx1, STF1, IPF1) is expressed in all cells of the pancreatic buds during development and will become restricted to the beta-cells in adult animals. Pdx1 mutant mice do not develop any exocrine nor endocrine tissue and do not have any pancreas (Jonsson et al. (1994) Nature, 371:606-609; Ahlgren et al. (1996) Development, 122:1409-1416; Offield et al. (1996) Development, 122:983-995). The basic helix-loop-helix transcription factor neurogenin3 (ngn3) is required for the specification of the early endocrine precursor in the pancreatic epithelium and is downregulated once endocrine differentiation begins (Apelqvist et al. (1999) Nature, 400:877-881; Jensen et al. (2000) Diabetes, 49:163-176; Gradwohl et al. (2000) Proc. Natl. Acad. Sci. U.S.A., 97:1607-1611). Two members of the Pax gene family, Pax4 and Pax6, are essential for proper differentiation of endocrine cells in the pancreas (Sosa-Pineda et al. (1997) Nature, 386:399-402; St-Onge et al. (1997) Nature, 397:406-409; Sanders et al. (1997) Genes Dev., 11:1662-1673). Both Pax genes are expressed early in development in a subset of endocrine precursor cells of the pancreatic epithelium, before differentiation of the mature hormone-producing cells. Mice lacking Pax4 fail to develop any beta-cells and are diabetic while the alpha-cell population is absent in Pax6 mutant mice. Nkx2.2, Nkx6.1, Nkx6.2, Isl1, and NeuroD are also among essential transcription factors required for the proper differentiation and function of beta-cells.
[0012] Several animal models for beta-cell regeneration suggest that the mechanisms involved in beta-cell differentiation in adult organism are similar to the mechanisms involved in beta-cell differentiation during embryogenesis. Gu and Savernick have established a model system for studying pancreatic islet and beta-cell regeneration in transgenic mice bearing the interferon-gamma (IFN-gamma) gene expressed in pancreatic islets. In this model, new islet cells (i.e. beta-, alpha-, delta- and PP-cells) are formed continuously from pancreatic duct cells (Gu and Savernick (1993) Development, 118:33-46). They show that duct cell proliferation and the duct-associated islet formation in IFN-gamma transgenic mice is recapitulating islet formation during development and requires the expression of Pax4, Pax6 and Pdx1 genes. Although a link exists between the genes involved in islet regeneration in adult animals and beta-cell differentiation during embryogenesis, it has not been shown in the prior art that activation of such genes in stem cells can induce the differentiation into insulin-producing cells.
SUMMARY OF THE INVENTION
[0013] The present invention relates a novel method for differentiating stem cells into insulin-producing cells by culturing such cells in specially defined media and optimally, activating one or more genes involved in beta-cell differentiation. The present invention further relates to applications in the medical and diabetes field that directly arise from the method of the invention. Additionally, the present invention relates to applications for identifying and characterising compounds with therapeutic medical effects or toxicological effects that directly arise from the method of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0014] Before the present methods are described, it is understood that this invention is not limited to the particular methodology, protocols, cell lines, vectors, and reagents described as these may vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to limit the scope of the present invention which will be limited only by the appended claims. Unless defined otherwise, all technical and scientific terms used herein have the same meanings as commonly understood by one of ordinary skill in the art to which this invention belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, the preferred methods, devices, and materials are now described. All publications mentioned herein are incorporated herein by reference for the purpose of describing and disclosing the cell lines, vectors, and methodologies which are reported in the publications which might be used in connection with the invention. Nothing herein is to be construed as an admission that the invention is not entitled to antedate such disclosure by virtue of prior invention.
[0015] A technical problem underlying the present invention is to provide a method for generating insulin-producing cells for transplantation in patients afflicted with pancreatic diseases, such as for example but not limited to, hyperglycaemia, impaired glucose tolerance, gestational diabetes, and diabetes mellitus. The solution to said technical problem is achieved by the embodiments characterised in the claims.
[0016] Thus, the present invention relates to methods for differentiating stem cells into insulin-producing cells comprising
(a) Activating one or more pancreatic genes in a stem cell (b) Aggregating said cells to form embryoid bodies (c) Cultivating embryoid bodies in specific differentiation media enhancing beta-cell differentiation (d) Identification and selection of insulin-producing cells and of pancreatic cells.
[0021] In connection with the present invention, the term “stem cells” denotes an undifferentiated or immature embryonic, adult or somatic cells that can give rise to various specialised cell types. The term stem cells can includes embryonic stem cells (ES) and primordial germ cells (EG) cells of human or animal origin. Isolation and culture of such cells is well known to those skilled in the art (Thomson et al. (1998) Science 282:1145-1147; Shamblott et al. (1998) Proc. Natl. Acad. Sci. USA 95:13726-13731; U.S. Pat. No. 6,090,622; U.S. Pat. No. 5,914,268; WO 0027995; Notarianni et al. (1990) J. Reprod. Fert. 41:51-56; Vassilieva et al. (2000) Exp. Cell. Res. 258:361-373). The term “stem cells” can include neural progenitor cells from embryonic, fetal or adult neural tissues. Isolation and culture of such cells is well known to those skilled in the art (Rao (Ed.), Stem Cells and CNS Development, Humana Press Inc., New Jersey (2001); Fedoroff and Richardson (Eds.), Protocols for Neural Cell Culture, Humana Press Inc., 3rd edition, New Jersey, (2001)).
[0022] The term “insulin-producing cell” means a cell capable of expressing, producing, and secreting insulin.
[0023] The term “cultivation medium” means a suitable medium capable of supporting growth and differentiation of stem cells, preferably ES and EG cells. Examples of suitable culture media in practising the present invention are prepared with a base of Dulbecco's modified Eagle's medium (DMEM, Life Technologies) supplemented with 15% heat-inactivated foetal calf serum (FCS, Gibco), and additives, such as 2 mM L-glutamine (Gibco), 5×10 −6 M β-mercaptoethanol (Serva) and 1:100 non-essential amino acids (Gibco). Another example is a culture medium comprising Iscove's modified Dulbecco's medium (IMDM, Gibco) supplemented with 20% FCS, 2 mM L-glutamine (Gibco), 1:100 non-essential amino acids (Gibco) and 450 μM α-monothioglycerol (Sigma). For routine cultures, ES cells are grown on a feeder layer of embryonic fibroblasts inactivated by treatment with 100 μg/ml mitomycin C for 3 hours.
[0024] The term “differentiation medium” means a suitable medium for inducing the differentiation of stem cells into insulin-producing cells. Examples of suitable culture media in practising the present invention are prepared with a base of Iscove's modified Dulbecco's medium (IMDM, Gibco) supplemented with 20% fetal calf serum (FCS), 2 mM L-glutamine, 1:100 non-essential amino acids and 450 μM α-monothioglycerol (Sigma). In addition, such medium can contain between 1 ng/ml and 100 μg/ml, preferably 10 ng/ml Epithelial Growth Factor (EGF); between 1 ng/ml and 100 μg/ml, preferably 2 ng/ml basic Fibroblast Growth Factor (bFGF); between 1 nM and 1 mM, preferably 20 nM progesterone; between 10 ng/ml and 100 μg/ml, preferably 100 ng/ml Growth hormone; between 1 nM and 100 μM, preferably 5 nM follistatin (R&D); or between 1 and 100 nM, preferably 2 nM activin (R&D). Another example of suitable culture media in practising the present invention is prepared with a base of Dulbecco's modified Eagle's medium: Nutrient Mixture F-12 (DMEM/F12, Life Technologies) supplemented with between 100 ng/ml and 100 μg/ml, preferably 5 μg/ml insulin; between 1 nM and 100 nM, preferably 30 nM sodium selenite; between 100 ng/ml and 500 μg/ml, preferably 50 μg/ml transferrin; between 100 ng/ml and 100 μg/ml, preferably 5 μg/ml fibronectin. Yet another example of suitable culture media in practising the present invention is prepared with a base of Dulbecco's modified Eagle's medium: Nutrient Mixture F-12 (DMEM/F12, Life Technologies) supplemented with between 100 ng/ml and 100 μg/ml, preferably 25 μg/ml insulin; between 1 nM and 100 nM, preferably 30 nM sodium selenite; between 100 ng/ml and 500 μg/ml, preferably 50 μg/ml transferrin; between 100 ng/ml and 100 μg/ml, preferably 5 μg/ml fibronectin; between 500 ng/ml and 100 μg/ml, preferably 1 μg laminin; between 10 μM and 500 μM, preferably 100 μM putrescine; between 1 nM and 1 μM preferably 20 nM progesterone; between 100 μM and 100 mM, preferably 10 mM nicotinamide.
[0025] In addition, extracellular matrix (ECM) proteins, such as laminin (between 0.5 and 100 μg/ml, preferably 1 μg/ml, SIGMA), or collagens, or complex mixtures of growth factors and ECM proteins of basal lamina (Matrigel R, Collaborative Research/Becton Dickinson, 1:3 dilution=stock solution, final concentration in cultures=1:10) are included to enhance the number of pancreatic cells as well as their differentiation status.
[0026] The term “terminal differentiation medium” means a suitable medium for terminal differentiation of insulin-producing cells. Examples of suitable culture media in practising the present invention are prepared with a base of Iscove's modified Dulbecco's medium (IMDM, Gibco) supplemented with 20% FCS, 2 mM L-glutamine, 1:100 non-essential amino acids and 450 μM α-monothioglycerol (Sigma). In addition, such medium can contain between 1 nM and 100 μM, preferably 2 nM Activin A; between 1 nM and 100 μM, preferably 1 nM betacellulin; between 1 ng/ml and 100 μg/ml, preferably 10 ng/ml Human Growth Factor (HGF); between 1 nM and 100 μM, preferably 10 nM Niacinamid and between 1 ng/ml and 100 μg/ml, preferably 2 ng/ml Transforming Growth Factor 2beta (TGF 2beta).
[0027] The term “pancreatic gene” means a gene or its protein product that is involved and required for pancreas development, more preferably beta-cell differentiation. Examples of such genes are Pdx1 (GenBank accession number AH005712), Pax4 (GenBank accession numbers XM004974, NM006193), Pax6 (GenBank accession number M93650), ngn3 (GenBank accession numbers XM005744, NM020999, AJ133776), Nkx6.1 (GenBank accession number AH007313), Nkx6.2, Nkx2.2 (GenBank accession number AF019415), HB9 (GenBank accession numbers XM049383, AF107457), BETA2/NeuroD (GenBank accession numbers NM002500, XM002573), Isl1 (GenBank accession number NM002202), HNF1-alpha, HNF1-beta (GenBank accession number X71346), and HNF3 (GenBank accession numbers AF176112, AF176111) of human or animal origin. Preferred genes are Pdx1, Pax4, Pax6, and ngn3. Especially preferred genes are Pdx1, Pax4, and Pax6. Each gene can be used individually or in combination.
[0028] The term “activating one or more pancreatic gene” means delivering and introducing said pancreatic genes or proteins into stem cells.
[0029] In a preferred embodiment, the cDNA of one or more pancreatic genes is placed under the control of a regulatory region allowing the initiation of transcription and introduced into a cell by transfection methods such as electroporation, lipofection, calcium phosphate mediated, DEAE dextrans, and the like. Such methods and system are well described in the art and do not require any undue experimentation; see, for example, Joyner, “Gene Targeting: A Practical Approach”, Oxford University Press, New York, 1993; Mansouri “Gene Targeting by Homologous Recombination in Embryonic Stem Cell”, Cell Biology: A Laboratory Handbook, second ed., Academic Press, 1998. Gene expression of pancreatic gene can be assured by constitutive promoters such as the Cytomegalovirus promoter/enhancer region or inducible promoters such as the tetracycline inducible system. Expression vectors can also contain a selection agent such as the neomycin, hygromycin or puromycin resistance genes. Making such gene expression vectors are well known in the art; see Sambrook et al., “Molecular Cloning, A laboratory Manual” third ed., CSH Press, Cold Spring Harbor, 2000; Gossen and Bujard, (1992) Proc. Natl. Acad. Sci. USA 89:5547-5551). DNA transfer can also be achieved using a viral delivery system such as retrovirus, adenovirus, adeno-associated virus and lentivirus vectors.
[0030] In a further preferred embodiment, protein products of pancreatic genes can be delivered directly to stem cells. For example, protein delivery can be achieved by polycationic liposomes (Sells et al. (1995) Biotechniques 19:72-76), Tat-mediated protein transduction (Fawell et al. (1993) Proc. Natl. Acad. Sci. USA 91:664-668) and by fusing a protein to the cell permeable motif derived from the PreS2-domain of the hepatitis-B virus (Oess and Hildt (2000) Gene Ther. 7:750-758). Preparation, production and purification of such proteins from bacteria, yeast or eukaryotic cells are well known by persons skilled in the art.
[0031] An additional embodiment of the present invention relates to a method for aggregating stem cells, preferably ES and EG cells, to form embryoid bodies. Embryoid bodies can be generated by a hanging drop method. For example, between 400-800 ES cells, preferably 600, are cultured in drops of 20 μl of Iscove modified Dulbecco's medium (IMDM, Gibco) supplemented with 20% FCS, L-glutamine, non-essential amino acids and α-monothioglycerol placed on the lids of petri dishes filled with phosphate-buffered saline (PBS). Embryoid bodies are cultured in hanging drops for 2 days at 37° C. with 5% CO 2 and then transferred to bacteriological petri dishes (Greiner, Germany) and incubated a further 3 days in suspension culture. After 5 days, embryoid bodies are plated onto gelatin-coated 24-well plates, petri dishes or other suitable culture container and cultured for an additional 15 to 35 days at 37° C. with 5% CO 2 . Embryoid bodies can also be produced in spinner cultures. For example, adherent stem cells are enzymatically dissociated using 0.2% trypsin and 0.05% EDTA in PBS (Life Technologies) and seeded at a density of 10 7 cell/ml in 250 ml siliconised spinner flasks (Life Technologies) containing 100 culture medium. After 24 hours, 150 ml culture medium is added to a final volume of 250. Spinner flasks are stirred at 20 rpm using a stirrer system (Integra Biosciences). Such methods are well known in the art and can be scaled up for industrial production without undue experimentation.
[0032] In a further embodiment of the invention, embryoid bodies are plated unto petri dishes containing differentiation medium and allowed to differentiate into insulin-producing cells for periods of 15 to 50 days, preferably 20 to 25 days (depending on the cell lines used; R1 wild type cells need longer differentiation for generating insulin or glucagon-positive cells than Pdx-1 + or Pax4 + cells). In the method of the invention a high proportion of insulin-producing cells is obtained. After a differentiation time of 15 days, the proportion of insulin-producing cells is preferably at least 20%, more preferably at least 40% and most preferably at least 50%.
[0033] The proportion of insulin-producing cells may further be increased by a selection of nestin-positive cells. This selection preferably comprises the transfer of embryoid bodies, e.g. obtained by the hanging drop method, to a suspension culture and subsequent plating and/or replating on a suitable medium, e.g. a poly-L-ornithine/laminin coated plate. The nestin selection procedure may lead to a further increase in the proportion of insulin-producing cells, e.g. a proportion of 70% or more.
[0034] In a further embodiment of the invention, differentiated insulin-producing cells can be isolated and purified using a method for selecting insulin secreting cell clones from ES cells by transfecting cells with a plasmid allowing the expression of neomycin, hygromycin or puromycin resistance gene under the control of the regulatory region of the human insulin gene. Cells can also be sorted using Fluorescent Activated Cell Sorting (FACS) after Hoechst 33342 dye staining (Goodell et al. (1996) J. Exp. Med. 183:1797-1806). Further modifications of the above-mentioned embodiment of the invention can easily be devised by the person skilled in the art, without undue experimentation from this disclosure.
[0035] An additional embodiment of the present invention relates to a method for treating diabetes wherein between 3000 and 100 000 equivalent differentiated insulin-producing cells per kilogram body weight would be introduced into a diabetic patient intraportally via a percutaneous transhepatic approach using local anaesthesia. Such surgical techniques are well known in the art and can be applied without any undue experimentation, see Pyzdrowski et al, “Preserved insulin secretion and insulin independence in recipients of islet autografts” New England J. Medicine 327:220-226, 1992; Hering et al., “New protocol toward prevention of early human islet allograft failure” Transplantation Proc. 26:570-571, 1993; Shapiro et al., “Islet transplantation in seven patients with type 1 diabetes mellitus using a glucocorticoid-free immunosuppressive regimen”, New England J. Medicine 343:230-238, 2000. Furthermore, encapsulation technology could also be used for the transplantation of differentiated insulin-producing cells as described by Lanza et al., “Encapsulated cell technology”, Nature Biotech 14:1107-1111, 1996.
[0036] Further, the invention relates to a cell composition comprising differentiated stem cells exhibiting insulin production, e.g. an insulin-producing cell line obtainable by the method as described above. The insulin-producing cells may exhibit a stable or a transient expression of at least one gene involved in β-cell differentiation, particularly a gene as described above. The cells are preferably human cells which are derived from human stem cells. For therapeutic applications the generation of autologous human cells from adult stem cells of a patient is especially preferred.
[0037] The insulin-producing cells of the invention exhibit characteristics which closely resemble naturally occurring β-cells. Particularly, the ratio of insulin-producing cells versus glucagon-producing cells is high. After 15 days of differentiation, this ratio is preferably at least 2:1 and more preferably at least 5:1. Further, the cells of the invention are capable of a quick response to glucose. After addition of 27.7 mM glucose, the insulin production is enhanced by a factor of at least 2, preferably by a factor of at least 3 in the cells of the invention. Further, the cells of the invention are capable of normalizing blood glucose levels after transplantation into mice.
[0038] The cell composition of the invention is preferably a pharmaceutical composition comprising the cells together with pharmacologically acceptable carriers, diluents and/or adjuvants. The pharmaceutical composition is preferably used for the treatment of diabetes. The administration is preferably by transplantation as described above.
[0039] In a further embodiment, the present invention allows the generation of cells for the identification and/or characterisation of compounds which stimulate beta-cell differentiation, insulin secretion or glucose response. This method is particularly suitable for in vivo testing for diagnostic applications and drug development or screening. The compound of interest is added to differentiated and undifferentiated insulin-producing cells which are grown in appropriate culture system, for example 96 and 384 well plates. Insulin levels in treated cells can be quantified by Enzyme Linked Immunoabsorbent Assay (ELISA) or Radio Immuno Assay (RIA). Using this method, a large number of compounds can be screened and compounds that induce beta-cell differentiation and increase insulin secretion can be identified readily.
[0040] Preferred embodiments for high-throughput screening and medium throughput validation methods are described in FIG. 11 . In a high-throughput screening method, the cells are transfected with a DNA construct, e.g. a viral or non-viral vector containing a reporter gene, e.g. the lacZ gene or the GFP gene, under regulatory control of a promoter of a gene involved in β-cell differentiation, e.g. a promoter of a gene as described above, preferably a Pax4 promoter. The transfected cells are divided into aliquots and each aliquot is contacted with a test substance, e.g. candidate 1, candidate 2 and candidate 3. The activity of the reporter gene corresponds to the capability of the test compound to induce β-cell differentiation.
[0041] In a further embodiment (which may be combined with the high-throughput screening as described above) a medium throughput validation is carried out. Therein, the test compound is added to stem cells being cultivated and the insulin production is determined. Following an initial high throughput assay, such as the cell based assay outlined above where e.g. a Pax4 promoter is used as marker for beta-cell regeneration, the activity of candidate molecules to induce beta-cell differentiation is tested in a validation assay comprising adding said compounds to the culture media of the embryoid bodies. Differentiation into insulin-producing cells is then evaluated, e.g. by comparison to wild type and/or Pax4 expressing ES cells to assess the effectiveness of a compound.
BRIEF DESCRIPTION OF THE DRAWINGS
[0042] FIG. 1 : Expression vectors containing the Pdx1, Pax4, Pax6, and ngn3 gene.
[0043] The Pdx1, Pax4, Pax6, and ngn3 (SEQ ID No. 1, 2, 3, 4) cDNA were inserted into the expression vector pACCMV.pLpA previously described by Becker et al. (Becker et al. (1994) Meth. Cell Biol. 43:161-189). Briefly, a Kpn I-Bam HI fragment that included the Pdx1 cDNA (SEQ ID No. 1) was introduce into the KpnI-BamHI sites of pACCMV.pLpA, placing the Pdx1 gene under the control of the Cytomegalovirus (CMVp) promoter. Likewise, a Bam HI-Hind III fragment that include the Pax4 cDNA (SED ID No. 2) was introduce into the Bam HI-Hind III sites of pACCMV.pLpA, placing the Pax4 gene under the control of the CMV promoter; a Bam HI-Hind III fragment that includes the Pax6 cDNA (SED ID No. 3) was introduced into the Bam HI-Hind III sites of pACCMV.pLpA, placing the Pax6 gene under the control of the CMV promoter; and a Bam HI-Xba I that includes the ngn3 cDNA (SEQ ID No. 4) was introduced into the Bam HI-Xba I sites of pACCMV.pLpA, placing the ngn3 gene under the control of the CMV promoter. Abbreviations: B, Bam HI; H, Hind III; K, Kpn I; X, Xba I; Ad 5, adenovirus type 5.
[0044] FIG. 2 . Differentiation of ES cells into insulin-producing cells
[0045] Wild type and Pdx1 expressing embryonic stem (ES) cells were cultivated as embryoid bodies (EB; EBs) by the hanging drops method. Differentiation and terminal differentiation media are applied upon plating of EBs.
[0046] FIG. 3 . Amount of hormone-producing cells in Pdx1+ differentiated ES cells
[0047] Immunofluorescence observation of insulin, glucagon, pancreatic polypeptide (PP) and somatostatin-positive cells following plating of Pdx1+ embryoid bodies cultured in normal culture medium and differentiation medium. Results illustrated over time in arbitrary units representing the average number of hormone-producing cells in define areas of the culture dishes. The number of hormone-producing cells (i.e. insulin, glucagon, PP, and somatostatin) is higher when embryoid bodies are cultured in differentiation and terminal differentiation media.
[0048] FIG. 4 . Expression of pancreas specific genes after differentiation of wild type, Pdx1 + , and Pax4 + ES cells into insulin-producing cells.
[0049] mRNA levels of pancreas specific genes following formation of embryoid bodies by the hanging drop method and plating in differentiation medium. Insulin and Glut2 levels are higher in Pdx1 + and Pax4 + ES cells than in wild type ES cells indicating that differentiation is more efficient when a pancreatic developmental control gene is activated.
[0050] FIG. 5 . Differentiation of mouse ES cells into insulin-producing cells.
[0051] The proportion of insulin-producing cells was determined in wild type cells (R1), and Pdx1 and Pax4 expressing cells, 5, 6, 10, and 15 days after plating.
[0052] FIG. 6 . Insulin-producing cells versus glucagon-producing cells.
[0053] The expression of insulin and glucagon in wild type ES cells, Pdx1 expressing cells and Pax4 expressing cells was determined 5, 10 or 15 days after plating.
[0054] FIG. 7 . Glucose response of Pax4 ES cell derived insulin cells.
[0055] The insulin secretion of wild type (R1) and Pax4 ES derived insulin-producing cells was determined in the absence of glucose and 15 minutes after stimulation with 27.7 mM glucose.
[0056] FIG. 8 . Regulation of blood glucose level in diabetic mice.
[0057] The blood glucose level of diabetic control mice (STZ control) and diabetic mice having received a transplant of insulin-producing cells derived from Pax4 ES cells was determined.
[0058] FIG. 9 . Drug screening strategies.
[0059] A high-throughput screening and a medium throughput validation method for three test compounds are shown. An initial high throughput screen is performed in a cell assay using Pax promoters as reporter for beta-cell differentiation. Positive candidates are then validated in a medium throughput assay involving embryoid bodies. Compounds are tested at different stages of culture for their potential to induce the formation of insulin-producing cells.
[0060] FIG. 10 . Differentiation methods of ES cells into insulin-producing cells using culture conditions favouring the formation of nestin-positive cells.
[0061] FIG. 11 . Differentiation of nestin-positive mouse ES cells into insulin-producing cells.
EXAMPLES
[0062] A better understanding of the present invention and of its many advantages will be had from the following examples, given by way of illustration.
Example 1
[heading-0063] Generation of ES Cells Expressing the Pdx1 or Pax6 Gene.
[0064] The mouse R1 ES cells (Nagy et al. (1993) Proc. Natl. Acad. Sci. USA. 90:8424-8) were electroporated with the Pax6 or the Pdx1 gene under the control of the CMV promoter (see FIG. 1 ) and the neomycin resistance gene under the control of the phosphoglycerate kinase I promoter (pGK-1). ES cells are cultured in Dulbecco's modified Eagle's medium (DMEM, Life Technologies) containing 4.5 g/l glucose, 10 −4 M beta-Mercaptoethanol, 2 nM glutamine, 1% non essential amino acids, 1 nM Na-pyruvate, 15% FCS and 500 U/ml leukaemia inhibitory factor (LIF). Briefly, approximately 10 7 ES cells resuspended in 0.8 ml phosphate buffered saline (PBS) containing 25 μg/ml of linearized expression vector and electroporated with one pulse of 500 μF and 250 volts at room temperature using a Gene Pulser electroporation apparatus (BioRad). Five minutes after electroporation, ES cells are plated on 8.5 cm petri dishes containing fibroblastic feeder cells previously inactivated by treatment with 100 μg/ml mitomycin C for 3 hours. One day after electroporation, culture medium is changed to medium containing 450 μg/ml G418. Resistant clones are separately isolated and cultured 14 days after applying the selection medium. Cells are always cultured at 37° C., 5% CO 2 .
Example 2
[heading-0065] Differentiation of ES Cells into Insulin-Producing Cells.
[0066] The ES cell line R1 (wild type, wt) and ES cells constitutively expressing Pdx1 (Pdx1+) were cultivated as embryoid bodies (EB; EBs) by the hanging drops method ( FIG. 2 ). Briefly, approximately 600 cells were placed in drops of 20 μl medium composed of Iscove modified Dulbecco's medium (IMDM, Gibco) supplemented with 20% FCS, L-glutamine, non-essential amino acids and alpha-monothioglycerol (Sigma, Steinheim, Germany; final concentration 450 μM). Drops were placed on the lids of petri dishes filled with phosphate-buffered saline (PBS). The EBs were allowed to form in hanging drops cultures for 2 days and then transferred for three days to suspension cultures in bacteriological petri dishes (Greiner, Germany). At day 5, EBs were plated separately onto gelatin-coated 24-well plates containing a differentiation medium prepared with a base of Iscove modified Dulbecco's medium (IMDM, Gibco) supplemented with 20% FCS, 2 mM L-glutamine, 1:100 non-essential amino acids, 450 μM α-monothioglycerol (Sigma), 10 ng/ml Epithelial Growth Factor (EGF, R&D Research), 2 ng/ml basic Fibroblast Growth Factor (bFGF, R&D Research), 20 nM progesterone (R&D Research), 100 ng/ml Human Growth Hormone (HGH, R&D Systems) and 5 nM follistatin (R&D Systems) and/or 2 nM human activin A (R&D Systems). Cells were cultured for 15 to 40 days in the differentiation medium. To enhance differentiation capacity, a terminal differentiation medium can be applied at stages between 5 and 20 days after EB plating.
Example 3
[heading-0067] Hormonal Expression in Differentiated ES Cells.
[0068] Expression of insulin, glucagon, somatostatin and pancreatic polypeptide (PP) was verified by immunofluorescence in differentiated wt and Pdx1+ ES cells. Immunofluorescence was performed according to standard protocols (see Wobus et al.: In Vitro Differentiation of Embryonic Stem Cells and Analysis of Cellular Phenotypes, In: Tymms, M. J. and Kola, I. (Eds.) Gene Knockout Protocols, vol. 158, Methods in Molecular Biology, Humana Press, Totowa, N.J., 2001). Briefly, differentiated wt or Pdx1+ ES cells are grown on cover slips and rinsed twice with PBS and fixed with methanol: acetone 7:3 at −20° C. for 10 min. The following antibodies were used: Mouse anti-insulin (Sigma-Aldrich Co.), rabbit anti-glucagon (Dako Corporation), rabbit anti-somatostatin (Dako Corporation), rabbit anti-PP (Dako Corporation) were used as primary antibody while Fluorescein (DTAF)-conjugated goat anti-mouse IgG (Jackson ImmunoResearch Laboratories) and Cy 3TM -conjugated goat anti rabbit IgG (Jackson ImmunoResearch Laboratories) were used as second antibody. In this study double immunostaining was performed, and the following pairs of antibodies were used: anti-insulin and anti-glucagon; anti-insulin and anti-somatostatin; anti-insulin and anti-PP. Cells were analyzed with a fluorescence microscope Optiphot-2 (Nikon) and a confocal laser scanning microscope (CLSM) LSM-410 (Carl Zeiss). Differentiated wt ES cells co-express insulin, glucagon, PP, and somatostatin indicating that the cells have not undergone maturation into single hormone-producing cells. However, differentiated Pdx1+ cells separately express either insulin or glucagon but, rarely both hormones at the same cells demonstrating that such cells achieve maturation into single hormone-producing cells. The number of hormone-producing cell is higher when Pdx1+ ES cells are cultured in a differentiation medium (see FIG. 3 ) illustrating that differentiation into insulin-producing cells is more efficient when a pancreatic developmental control gene is expressed in a stem cell (e.g. ES) and when such cells are cultured in a differentiation medium.
Example 4
[heading-0069] Expression of Pancreas Specific Genes after Differentiation of ES Cells into Insulin-Producing Cells.
[0070] Expression levels of pancreas specific genes was measured by semi-quantitative RT-PCR analysis. Differentiated wild type, Pdx-1 + and Pax4 + cells have been collected after embryoid body formation (5d) and 2, 7, 10, 15, 21 and 24 days after plating (5+2d, +7d, +10d, +15d, +21d, +24d) were suspended in lysis buffer (4 M guanidinium thiocyanate, 25 mM sodium citrate, pH 7; 0.5% sarcosyl, 0.1 M beta-mercaptoethanol). Total RNA was isolated by the single step extraction method described by Chomczynski and Sacchi (Chomczynski and Sacchi (1987) Anal. Biochem. 162: 156-159). mRNA was reverse transcribed using PolyT tail primer Oligo d(T) 16 (PerkinElmer) and the resulting cDNA was amplified using oligonucleotide primers complementary and identical to transcripts of the following genes: GLUT2 (SEQ ID No 9 and 10; annealing temperature 60° C. for 40 cycles, expected fragment size 556 bp), insulin (SEQ ID No 11 and 12; annealing temperature: 60° C. for 40 cycles, expected fragment size 340 bp), ngn-3 (SEQ ID No 13 and 14; annealing temperature: 60° C. for 40 cycles, expected fragment size 514 bp), Pdx-1 (SEQ ID No 15 and 16; annealing temperature: 60° C. for 45 cycles, expected fragment size 230 bp) and Isl1 (SEQ ID No 17 and 18; annealing temperature: 60° C. for 40 cycles, expected fragment size 514 bp). The house keeping gene beta-tubulin (SEQ ID No 19 and 20, annealing temperature: 60° C. for 28 cycles, expected fragment size 317 bp) was used as internal standard. Reverse transcription (RT) was performed with MuLV reverse transcriptase (Perkin Elmer). Multiplex PCRs were carried out using AmpliTaq DNA polymerase (Perkin Elmer) as described in Wobus at al., 1997. Briefly, RT reactions (20 μl) were performed with MuLV reverse transcriptase. Separate PCRs using primers of the analysed genes or primers of the house keeping gene beta-tubulin were carried out with 3 μl of the RT products. mRNA levels of genes encoding Pax4 and insulin were analysed using the Dynalbeads mRNA DIRECT micro kit (Dynal) according to the manufacturer's instructions.
[0071] One third of each PCR reaction was separated by electrophorese on 2% agarose gels containing 0.35 μg/ml of ethidium bromide. Gels were illuminated with UV light and the ethidium bromide fluorescence signals of gels were stored by the E.A.S.Y. system (Herolab) and analyzed by the TINA2.08e software (Raytest Isotopenmeβgeräte GmbH). The intensity of the ethidium bromide fluorescence signals was determined from the area under the curve for each peak and the data of target genes were plotted as percentage changes in relation to the expression of the housekeeping gene beta-tubulin.
[0072] Results show that markers for beta-cell differentiation function were expressed at higher levels in Pdx1 + and Pax4 + differentiated ES cells than in differentiated wild type ES cells demonstrating that activation of a pancreatic developmental control gene renders differentiation more efficient than for wild type ES cells ( FIG. 4 ). Expression of GLUT2 in differentiated stem cells indicates that hormone-producing cells are capable of responding to glucose. In addition, genes involved in early endodermal/pancreatic precursor cell specification such as ngn3 and Isl1 are downregulated in Pdx-1 + and Pax4 + ES cells, consistent with in vivo data indicating that such cells have matured into single hormone-producing cells.
Example 5
[heading-0073] Hormonal Expression of Differentiated ES Cells Expressing Pdx1 and Pax4
[0074] In order to study the potential of pancreatic developmental control to induce beta-cell differentiation in vitro, we have generated stable mouse embryonic stem (ES) cells expressing the Pax4 or Pdx1 gene under the control of the cytomegalovirus (CMV) early promoter/enhancer region (see FIG. 1 a,b ). The CMV-Pax4 and CMV-Pdx1 transgenes were introduced into ES cells by electroporation, a method that is well known in the art, for example see Joyner, “Gene Targeting: A Practical Approach”, Oxford University Press, New York, 1993; Mansouri “Gene Targeting by Homologous Recombination in Embryonic Stem Cell”, Cell Biology: A Laboratory Handbook, second ed., Academic Press, 1998. Pax4, Pdx1 and wild type ES cells were then cultured in hanging drops or spinner cultures to allow the formation of embryoid bodies. Embryoid bodies were subsequently plated and cultured in a differentiation medium containing various growth factors. Under such conditions, insulin-producing cells can be detected in Pdx1 and Pax4 expressing cells six days after plating ( FIG. 5 ). By comparison, wild type ES cells did not contain any insulin-producing cell at the same stage. Ten days after plating, 12% of Pdx1 and Pax4 expressing cells were positive for insulin while the first insulin-producing cells are observed in wild type ES cells. At day 15 of plating, up to 60% of the Pax4 ES cells are positive for insulin compared to 22% for Pdx1 ES cells and 6% for wild type ES cells. These data demonstrate that Pax4, and to some extent Pdx1, can significantly promote, and enhance ES cells differentiation into insulin-producing cells compared to wild type ES cells.
[0075] The expression of Pax4 also affects the differentiation status of the insulin-producing cell. During embryogenesis, the first hormone-producing cells to arise in the developing pancreas co-express both insulin and glucagon. These cells subsequently differentiate and mature into single hormone-producing cells. In a similar fashion, all insulin-producing cells obtained from wild type ES cells also co-express glucagon suggesting that differentiation of the cells is arrested at a premature stage ( FIG. 6 ). Such cells most likely have little therapeutic value since insulin and glucagon have opposing effect on blood glucose levels in an organism. However in Pax4 ES cells, single insulin-producing cells are generated in substantial amounts ( FIG. 6 ). Insulin-glucagon co-expressing cells are detected in small numbers and most likely represent an ongoing differentiation process within the cultures. This observation demonstrate that Pax4 induces, and enhances the differentiation of insulin-producing cells which are more mature than the cells observed in wild type ES cells.
Example 6
[heading-0076] Functional Characterisation of the Differentiated Insulin-Producing Cells.
[0077] One important property of beta-cells is glucose responsive insulin secretion. To test whether the Pax4 derived insulin-producing cells possessed this glucose responsive property, in vitro glucose responsive assay was performed on the differentiated cells. Briefly, between 10 and 14 embryoid bodies were cultured in 3 cm petri dishes containing the above mentioned differentiation medium. On the day of the assay, the differentiation medium was removed and the cells were washed 3 times with Krebs Ringer Bicarbonate Hepes Buffer (KRBH; 118 mM NaCl, 4.7 KCl, 2.5 mM CaCl 2 , 1.2 mM KH 2 PO 4 , 1.2 mM MgSO 4 , 24.6 NaHCO 3 , 10 mM Hepes, 2 mg/ml BSA). Cells were then incubated in 750 μl KRBH for 45 minutes at 37° C. The KRBH was then kept for measurement of basal insulin secretion and 750 μl KRBH containing 27.7 mM glucose was added to the cells. After 15 minutes incubation at 37° C., the KRBH was removed from the cells for measurement of glucose induce insulin secretion. Insulin levels were determined by Enzyme-Linked Immunosorbent Assay (ELISA) for mouse insulin (Mercodia) and performed according to the manufacturer's recommendations. An alternative medium for proper insulin release is medium based on DMEM with glucose concentration of 1 g/l (Gibco) supplemented with non-essential amino acids (Gibco, stock solution 1:100) and additional factors mentioned above. Such medium can be applied 1 to 6 days before use of the cells.
[0078] A basal insulin secretion is observed when both wild type and Pax4 ES derived insulin-producing cells are cultured in the absence of glucose ( FIG. 7 ). However, only the Pax4 ES derived insulin-producing cells respond to glucose stimulation. In the presence of glucose, a five fold increase in insulin secretion is seen in Pax4 ES derived insulin-producing cells. Wild type ES derived insulin-producing cells do not respond to glucose.
Example 7
[heading-0079] Transplantation of Pax4 ES Derived Insulin-Producing Cells in STZ Diabetic Mice.
[0080] The therapeutic potential of Pax4 ES derived insulin-producing cells to improve and cure diabetes was investigated by transplanting the cells into streptozotocin induced diabetic mice. Streptozotocin is an antibiotic which is cytotoxic to beta-cells when administered at certain dosage (see Rodrigues et al.: Streptozotocin-induced diabetes, in McNeill (ed) Experimental Models of Diabetes, CRC Press LLC, 1999). Its effect is rapid, rendering an animal severely diabetic within 48 hours.
[0081] Non-fasted Male BalbC mice were treated with 170 mg/Kg body weight STZ. Under such conditions, 17 control mice developed hyperglycaemia 6 days after STZ treatment. Mice are considered diabetic if they have a blood glucose level above 10 mMol/l for more than 3 consecutive days. One mouse did not respond to the STZ treatment. Elevated blood glucose levels varied significantly between animals and between days. This is indicative of diabetes since the animals cannot regulate their blood glucose. Cells were transplanted under the kidney capsule and into the spleen of animals. Briefly, mice were anaesthetised by intraperitoneal injection of 15 μl/g body weight avertin (2.5% tribromoethyl alcohol:tertiary amyl alcohol). The kidney and the spleen was exposed through a lumbar incision, and cells were transferred into each tissue using a blunt 30G needle.
[0082] Transplantation of cells under the kidney capsule and into the spleen were performed 24-48 hours after STZ treatment. 8 animals were transplanted with between 1×10 6 and 5×10 6 Pax4 ES derived insulin-producing cells. 4 out of 8 transplanted animals died due to the surgical procedure. Of the 4 animals that did survived, none developed diabetes when compared with STZ-treated control animals ( FIG. 8 ). The presence of the insulin-producing cells was confirmed by immunohistological analysis of the transplanted tissue. These results demonstrate that the transplanted cells can normalise blood glucose in diabetic animals.
Example 8
[heading-0083] Differentiation of ES Cells into Insulin-Producing Cells Using Culture Conditions Favouring the Formation of Nestin-Postive Cells.
[0084] For differentiation of nestin-positive cells, mouse ES cells were cultivated for 2 days in hanging drops (100, 200, or 400 cells/drop) to form embryoid bodies (EBs; FIG. 10 ). EBs were then transferred to bacteriological petri dishes (Greiner, Germany) and cultivated for additional 2 days in Iscove's modification of DMEM (IMDM; Gibco) containing 20% FCS and supplements as described (Rohwedel et al., 1998), Dev. Biol. 201(2):167-184), with the exception that beta-mercaptoethanol was replaced by 450 mM alpha-monothioglycerol (Sigma, Steinheim, Germany). Between 20 and 30 EBs were plated onto tissue culture dishes (diameter 6 cm) at day 4, and cultivated in IMDM supplemented with 20% FCS for 24 hours. The selection of nestin-positive cells was carried out according to the method described by Okabe and colleagues (Okabe et al., 1996, Mech. Dev. 59:89-102) with the following modifications: After attachment of EBs (day 4+1), the medium was exchanged for a B1 medium prepared with a base of Dulbecco's modified Eagle's medium: Nutrient Mixture F-12 (DMEM/F12, Life Technologies) supplemented with 5 mg/ml insulin, 30 nM sodium selenite (both from Sigma), 50 mg/ml transferrin, and 5 mg/ml fibronectin (both from Gibco). The B1 culture medium was replenished every 48 hours. Nestin-positive cells were selected after cultivation for 7 days (=4+7d). At day 4+8, EBs were dissociated with 0.1% trypsin (Gibco)/0.08% EDTA (Sigma) in phosphate buffered saline (PBS) (1:1) for 1 min, collected by centrifugation, and replated onto poly-L-ornithine/laminin-coated tissue culture dishes containing a B2 medium prepared with a base DMEM/F12 supplemented with 10% FCS; 20 nM progesterone; 100 mM putrescine; 1 mg/ml laminin (all from Sigma); 25 mg/ml insulin; 50 mg/ml transferrin; 30 nM sodium selenite; B27 supplement; and 10 mM nicotinamide. This medium was replaced after 24 hours with B2 medium lacking FCS. At day 30 of plating; >75% of the Pax4 ES cells are positive for insulin compared to 20% for wild type ES cells ( FIG. 11 ).
[0085] All publications and patents mentioned in the above specification are herein incorporated by reference. Various modifications and variations of the described method and system of the invention will be apparent to those skilled in the art without departing from the scope and spirit of the invention. Although the invention has been described in connection with specific preferred embodiments, it should be understood that the invention as claimed should not be unduly limited to such specific embodiments. Indeed, various modifications of the described modes for carrying out the invention which are obvious to those skilled in molecular biology or related fields are intended to be within the scope of the following claims.
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The present invention relates a novel method for differentiating stem cells into insulin-producing cells by culturing such cells in specially defined media and optimally, activating one or more genes involved in beta-cell differentiation. The present invention further relates to applications in the medical (particularly diabetes) field that directly arise from the method of the invention. Additionally, the present invention relates to applications for identifying and characterising compounds with therapeutic medical effects or toxicological effects that directly arise from the method of the invention.
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CROSS-REFERENCE TO RELATED APPLICATION
This application claims the priority of U.S. provisional application Ser. No. 60/430,083, filed on Dec. 2, 2002.
FIELD OF INVENTION
The present invention relates generally to lithium polymer batteries and more specifically to a manufacturing process for extruding and assembling components of electrochemical cells for lithium polymer batteries.
BACKGROUND OF THE INVENTION
Rechargeable batteries manufactured from laminates of solid polymer electrolytes and sheet-like anodes and cathodes display many advantages over conventional liquid electrolyte batteries. These advantages include lower overall battery weight, high power density, high specific energy, longer service life, as well as being environmentally friendly since the danger of spilling toxic liquid into the environment is eliminated.
Solid lithium polymer battery components include positive electrodes, negative electrodes and an insulating material capable of permitting ionic conductivity, such as a solid electrolyte consisting of a polymer and a lithium salt sandwiched between the positive and negative electrodes. The anodes or negative electrodes are usually made of light-weight metals foils, such as alkali metals and alloys, typically lithium metal, lithium oxide, lithium-aluminum alloys and the like. The composite cathodes or positive electrodes are usually formed of a mixture of active material such as transitional metal oxide, an electrically conductive filler, usually carbon particles, and an ionically conductive polymer electrolyte material, the mixture being set on a current collector, which is usually a thin sheet of aluminum. Since solid polymer electrolytes are less conductive than liquid polymer electrolytes, solid or dry electrochemical cells must be prepared from very thin films (total thickness of approximately 50 to 250 microns) to compensate the lower conductivity with high film contact surfaces and to provide electrochemical cells with high power density.
Composite cathode thin films are usually obtained by solvent coating onto a current collector or by melt extrusion. Similarly, the polymer electrolyte separator layer is typically produced by solvent coating or by melt extrusion.
Solid lithium polymer electrochemical cells are typically manufactured by separately preparing the positive electrode, the electrolyte separator and the negative electrode. The positive electrode is initially coated onto a metallic foil (for example aluminum) or onto a metallized plastic film, which serves as a current collector. The polymer electrolyte is coated onto a plastic substrate, such as a film of polypropylene. The positive electrode is thereafter laminated onto one face of the electrolyte, then the plastic substrate is removed from the second face of the electrolyte and the lithium negative electrode is applied thereon. This manufacturing process which is reasonably efficient for research and development and small scale production of lithium polymer electrochemical cells is inadequate for large scale production. U.S. Pat. No. 5,536,278 to Armand et al. disclosed one such method of assembling the various components of a solid lithium polymer electrochemical cells.
U.S. Pat. No. 5,100,746 to Gauthier disclosed a method of laminating simultaneously a plurality of layers of components of an electrochemical cell that is adapted to speed up the manufacturing process, wherein double-layer solid polymer electrolyte/composite positive electrode sub-assemblies are subsequently associated with the other constituent layers of the electrochemical cell. However, the double-layer solid polymer electrolyte/composite positive electrode sub-assemblies are previously produced by successive lamination of positive electrodes and solid polymer electrolytes.
In order to improve the efficiency of the production process for large scale manufacturing of lithium polymer batteries, there is a need for a faster yet reliable method and apparatus for the production of multiple-layer solid polymer electrolyte/composite positive electrode sub-assemblies for thin film solid lithium polymer electrochemical cells.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide an improved method of making and assembling components of a thin film solid lithium polymer electrochemical cell.
It is another object of the present invention to provide an apparatus for simultaneously making and assembling components of a thin film solid lithium polymer electrochemical cell.
As embodied and broadly described herein, the invention provides a process of co-extrusion of a thin electrode sheet with a thin electrolyte polymer sheet directly onto a current collector sheet for a lithium polymer battery, the process comprising the steps of:
(a) mixing a polymer with active electrode material, lithium salt and electronic conductive material in a first mixing chamber to form an electrode slurry; (b) mixing a polymer with a lithium salt in a second mixing chamber to form an electrolyte slurry; (c) feeding the electrode slurry through a first flow channel and the electrolyte slurry through a second flow channel; (d) extruding the electrode slurry in the form of a thin electrode sheet through a first die opening connected to the first flow channel, the electrode slurry being extruded directly onto a current collector sheet; and (e) extruding the electrolyte slurry in the form of a thin electrolyte sheet through a second die opening adjacent to the first die opening and connected to the second flow channel; the thin electrolyte sheet being extruded directly onto the thin electrode sheet.
As embodied and broadly described herein, the invention also provides an apparatus for co-extruding components of an electrochemical cell of a lithium polymer battery onto a current collector sheet, the apparatus comprising a plurality of passageways linking a plurality of extruders to at least one die; the at least one die having at least two flow channels connected to at least two die openings, the at least one die adapted to extrude distinct sheets of material onto a current collector sheet.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be better understood and other advantages will appear by means of the following description and the following drawings in which:
FIG. 1 is a schematic frontal cross-sectional view of a co-extrusion apparatus according to a first embodiment of the invention;
FIG. 2 is a schematic frontal cross-sectional view of a co-extrusion apparatus according to a second embodiment of the invention;
FIG. 3 is an enlarged cross-sectional view of a multiple slot die shown in FIG. 2 adapted for co-extrusion on each side of a current collector sheet;
FIG. 4 is a schematic view of a measuring apparatus for measuring the thickness of a bi-face co-extrusion assembly;
FIG. 5 is a schematic cross-sectional view of a pair of co-extrusion apparatus according to a third embodiment of the invention positioned one after the other along the traveling path of a current collector;
FIG. 6 is a schematic cross-sectional view of a pair of co-extrusion apparatus according to a fourth embodiment of the invention;
FIG. 7 is a schematic cross-sectional view of a co-extrusion apparatus according to a fifth embodiment of the invention; and
FIG. 8 is a schematic cross-sectional view of a co-extrusion apparatus according to a sixth embodiment of the invention.
DETAILED DESCRIPTION
In general, the production of thin sheets of polymer electrolyte separator and thin sheets of composite cathode thin sheets is most efficient by melt extrusion through a slit die. The various constituents of the electrolyte separator or of the composite cathode are fed from one or more hoppers into an extruder, where they are melted, mixed and transported through an air tight cylinder via a mixing screw. The molten material is extruded toward the slit die and discharged through an elongated discharge port of the slit die at a constant rate onto a substrate sheet or film, where the slit die is adjusted to the desired thickness of film or sheet. Electrolyte separator and composite cathode materials are different from typical thermoplastic resins for instance and are difficult to extrude as some of their constituents remain in solid form through the melting step of the extrusion process. Furthermore, polymers of the polyether family, such as polyethylene oxide, have low melting points and become unstable under normal extrusion conditions such as high temperature and high shear conditions. As disclosed in co-pending U.S. application No. 60/362,079 which is hereby incorporated by reference, the applicants were able to solve the problems associated with the extrusion process of such material and, based on their ability to reliably extrude composite cathode thin sheets and electrolyte polymer separator thin sheets, have further improved the production process of thin film or sheet electrochemical cells as is described below.
To further improve the production process, multiple discharge slot dies were developed such that a composite cathode thin sheet and an electrolyte polymer separator thin sheet may be extruded concurrently onto a substrate such as a current collector. The current collector for the cathode material is typically a thin aluminum foil, nickel foil, iron or stainless steel foil or a polypropylene substrate with a thin layer of conductive metal particles thereon. The so-called co-extrusion production process may further comprise optical and/or ultra-sonic and/or Gamma gauges and/or Beta gauges measuring devices or any suitable measuring devices known to those skilled in the art adapted to measure the thickness of the various layers being extruded to ensure that the extruded layers remain within strict tolerances.
With reference to FIG. 1 , there is shown an co-extrusion apparatus 10 according to a first embodiment of the invention adapted to produce mono-face current collector/cathode/electrolyte laminates. Co-extrusion apparatus 10 comprises a main structural body 12 to which is connected a first extruder 14 , a second extruder 16 and a double slot die 15 . First extruder 14 mixes and extrudes composite cathodic material and second extruder 16 mixes and extrudes polymer electrolyte material.
A pair of inner passageways 20 and 22 link the exit ports of extruders 14 and 16 to double slot die 15 . The exit port 18 of extruder 14 is aligned with inner passageway 20 , through which molten material fed from extruder 14 is directed toward double slot die 15 . The exit port 17 of extruder 16 is aligned with inner passageway 22 , through which molten material fed from extruder 16 is directed toward double slot die 15 . Passageway 20 is divided into two main sections 24 and 26 . Section 24 comprises an expansion chamber 28 adapted to regulate the flow of molten material; from expansion chamber 28 , the molten material is fed into a wider section 26 leading directly into double slot die 15 . Section 26 of passageway 20 comprises a tubular ram 30 , whose diameter is equal to that of section 26 and is adapted to move into the path of the molten material to partially block the exit port 29 of section 24 , thereby regulating the flow of molten material fed into double slot die 15 . The motion of tubular ram 30 is controlled by either a hydraulic motor or an electric motor, capable of exact positioning of the tubular ram 30 relative to exit port 29 . The electric or hydraulic motor is connected to a control system that regulates the debit of molten material in response to various parameters, which are described further down. Similarly, passageway 22 is divided into two main sections 34 and 38 . Section 24 comprises an expansion chamber 36 adapted to regulate the flow of molten material fed from extruder 16 ; from expansion chamber 36 , the molten material is fed at constant pressure into a wider section 38 leading directly into double slot die 15 . Section 38 of passageway 22 comprises a tubular ram 32 adapted to move into the path of the molten material and partially block the exit port 39 of section 34 , thereby regulating the flow of molten material fed into double slot die 15 .
Double slot die 15 is mounted onto the main structural body 12 of co-extrusion apparatus 10 . Double slot die 15 comprises a pair of flow channels 42 and 44 aligned with the exit ports 41 and 43 respectively. Flow channels 42 and 44 are shaped as fish tails or coat hangers to reconfigure the flow of each molten material into a thin film, which exit through adjacent slit openings 46 and 48 calibrated to the desired thickness of extruded films ranging from 10 to 100 Microns. The slit openings 46 and 48 may be calibrated during machining of the double slot die 15 or provided with adjustments for fine tuning, as is well known in the art of die making. Slit opening 46 is calibrated or adjusted to discharge a cathode thin sheet of about between 20 and 80 microns and slit opening 48 is calibrated or adjusted to discharge an polymer electrolyte separator of about between 10 and 50 microns, depending on the end use of the electrochemical cell to be produced. It is understood that double slot die 15 may be calibrated or adjusted to any thickness required; however, the efficiency of the electrochemical cells being produced is maximized with very thin sheets. When calibrated slit openings are worn such that the thickness of the extruded thin sheets exceeds a set tolerance by, for example, 5 microns, the entire double slot die 15 is replaced. Co-extrusion apparatus 10 may be equipped with a turret (not shown) comprising two or more double slot dies 15 , such that rotation of the turret will align a new double slot die 15 with exit ports 41 and 43 and co-extrusion may resume with minimal delay when the die must be replaced. The worn out die is removed from the turret and a new die installed in its place without undue interruption of production.
A continuous composite cathode thin sheet 50 of, for example, 60 μm±5 μm exits slit opening 46 and is deposited directly onto a moving current collector thin sheet 54 . Current collector 54 may be a thin metallic foil of, for example, 15-50 μm, or a thin metallized polymer film of similar thickness. Simultaneously, a continuous polymer electrolyte separator thin sheet 52 of for example 25 μm±5 μm exits slit opening 48 and is deposited onto the composite cathode thin sheet 50 . As shown in FIG. 1 , in a preferred embodiment of the co-extrusion manufacturing process, the assembly of current collector/composite cathode/electrolyte separator 55 immediately passes between a pair of flat cylinder rollers 60 and 62 driven at constant speed, flat cylinder roller 60 driving current collector 54 at a set speed. Flat cylinder rollers 60 and 62 are mounted on pivotal support structure 64 and 66 , each having an hydraulic cylinder 68 adapted to adjust the exact position of the cylinder rollers 60 and 62 and also to adjust the pressure applied onto assembly 55 as it passes between the cylinder rollers 60 and 62 it is understood that other means and constructions for adjusting the position of the cylinder rollers 60 and 62 and the pressure applied on the assembly 55 by the cylinder rollers 60 and 62 are contemplated and within the reach of a person skilled in the art and as such are within the scope of the present invention. The pressure applied by cylinder rollers 60 and 62 helps to promote adhesion of the various layers of assembly 55 together. To prevent adhesion of the electrolyte separator thin sheet 52 to flat cylinder roller 62 , flat cylinder roller 62 may be maintained at temperatures below the ambient temperature and preferably at a temperature ranging from −40° C. to 10° C. To prevent adhesion, flat cylinder roller 62 may also be provided with an anti-adhesive liner.
As a variant of the co-extrusion manufacturing process, the extruded cathode sheet 50 and electrolyte sheet 52 may be stretched onto current collector 54 in order to marginally reduce the overall thickness of assembly 55 . The stretching is achieved by selecting the speed at which the current collector 54 travels at the contact point between the extruded cathode material 50 and the current collector 54 , such that the speed of current collector 54 exceeds the rate of discharge of double slot die 15 . The speed differential between the current collector 54 and the cathode material exiting slit die opening 46 marginally stretches the extruded cathode sheet 50 , thereby reducing its thickness and consequently the overall thickness of assembly 55 . Since the current collector may be a very thin metallic foil such as aluminum foil of 25 μm, stretching cathode sheet 50 with speed differential may cause ripping of the metallic foil, in which case it is no longer feasible.
In a variant, a polypropylene thin sheet 56 shown in dotted lines is added on the side of the polymer electrolyte separator sheet 52 to protect the electrolyte separator. The polypropylene thin film 56 is removed prior to lamination of an anode film on the electrolyte separator layer, as described in U.S. Pat. No. 5,100,746 which is hereby incorporated by reference in its entirety. Although optional, when assembly 55 is brought to a further processing station where an anode film is laminated over assembly 55 , the polypropylene thin sheet 56 is important for storing assembly 55 into rolls for future use.
Assembly 55 winds through a series of rollers 70 to maintain a set tension on the continuous sheets and is brought to a measuring station 75 comprising a series of mechanical, optical, ultra sonic, Gamma or Beta measuring devices to control the thickness of the various layers of assembly 55 . In this particular embodiment, there are two layers to be measured; cathode sheet 50 and electrolyte separator sheet 52 . Therefore, measuring station 75 comprises three measuring devices 76 , 77 and 78 . The first measuring device 76 measures the overall thickness of the entire assembly 55 , including current collector 54 , cathode sheet 50 , electrolyte separator sheet 52 and, optionally, polypropylene sheet 56 . Note that the current collector 54 and, when used, polypropylene sheet 56 are known quantities. The second measuring device 77 is for example an optical device calibrated to measure the thickness of electrolyte separator sheet 52 , which is a material allowing light transmission. A Light wave is sent though electrolyte sheet 52 at an angle. A portion of the light wave is reflected off the first surface of electrolyte sheet 52 and a portion of the light wave is transmitted through electrolyte sheet 52 and is reflected by the second surface of electrolyte sheet 52 . The two light reflections are received by optical measuring device 77 , which calculates the perpendicular thickness of electrolyte sheet 52 . If a polypropylene sheet 56 is used, the light reflected off its surfaces may be discarded. The third measuring device 78 is an ultra sonic, Gamma or Beta device calibrated to measure the thickness of cathode sheet 50 . Because the cathodic material layer is opaque, these types of waves are better suited to measure its thickness.
Measuring devices 76 , 77 and 78 are linked to an electronic control unit such as a computer which is continuously fed data representative of the thickness of electrolyte sheet 52 and of cathode sheet 50 . This data is monitored by comparing it to pre-set thickness tolerances. When a thickness measurement falls outside the pre-set tolerances, an alarm signal is sent and the double slot die 15 may be adjusted manually by an operator receiving the alarm signal, or replaced altogether as previously described with a rotation of the die turret to change the double slot die 15 . The electronic control unit also monitors trends in the thickness measurement data received. The electronic control unit is linked to the system controlling the debit of molten material through passageways 20 and 22 via the motors controlling the position of both tubular rams 30 and 32 , and to the system controlling the speed and pressure of cylindrical roller 60 and 62 . The debit of cathode and electrolyte material may also be adjusted directly at the extruder's level by marginally increasing or decreasing the flow rate adjusting the throughput of the pumping device. The variables of debit, speed and pressure of rollers may be adjusted according to signals received from the electronic control unit, with the effect of providing minor adjustments to the thickness of electrolyte sheet 52 and of cathode sheet 50 . Other means of controlling the debits of cathode material and electrolyte material other than the illustrated tubular rams are possible and contemplated and within the competence of the skilled technician. Examples of such means are numerous and include valves and adjustable restrictions of the passageways or exit ports or even at the die exit.
For example, a detected increase in the thickness of cathode sheet 50 may be compensated by a decrease in the debit of molten cathodic material, which is effected by moving tubular ram 30 thereby partially blocking the flow of molten material through the exit port 29 of section 24 of passageway 20 , and simultaneously decreasing the flow rate of extruder 14 gear pump. Furthermore, the speed of current collector 54 may also be marginally increased by increasing the speed of rollers 60 and 62 to increase the stretching of cathode sheet 50 . Various responses to deviating thickness of electrolyte sheet 52 and cathode sheet 50 are pre-programmed, stored into memory, retrieved and initiated when corresponding thickness measurement data are received. Although limited, the ability of the system to effect minute adjustments of the thickness of electrolyte sheet 52 and cathode sheet 50 improves the quality of the final product.
Obviously, other means of measuring the thickness of the co-extruded layers are contemplated and well within the scope of the disclosed invention. The measurement is used to provide quality control of the co-extruded sheets and also to provide references for minute adjustments of the co-extrusion process.
With reference to FIG. 2 , there is shown a co-extrusion apparatus 100 according to a second embodiment of the invention, adapted to produce bi-face current collector/cathode/electrolyte separator laminates. Co-extrusion apparatus 100 comprises a main structural body 102 , to which are connected four extruders 104 , 106 , 108 and 110 and a multiple slots die 105 mounted at the discharged end of co-extrusion apparatus 100 . Extruders 106 and 110 mix and extrude composite cathodic material. Extruders 104 and 108 mix and extrude polymer electrolyte material. Co-extrusion apparatus 100 comprises a central passageway 112 adapted to guide a current collector thin sheet 154 directly into multiple slots die 105 . Central passageway 112 extends the Length of co-extrusion apparatus 100 , from a first end 114 which receives current collector sheet 154 to a second end 116 which guides current collector sheet 154 into multiple slots die 105 .
Co-extrusion apparatus 100 comprises a first pair of inner passageways 120 and 122 linking the exit ports of extruders 106 and 110 to multiple slot die 105 . The path of passageways 120 and 122 leads the extruded cathode material toward the central portion of multiple slot die 105 on each side of current collector 154 , such that a sheet of extruded cathode material will be laid directly onto each side of current collector 154 . Passageways 120 and 122 are divided into two main sections 124 and 126 . Sections 124 comprises expansion chambers adapted to regulate the flow of the molten cathode material; from expansion chamber, the molten cathode material is fed into the wider sections 126 leading directly into multiple slot die 105 . Each section 126 comprises a tubular ram 130 whose diameter is equal to that of section 126 and is adapted to move into the path of the molten cathode material to partially block the exit ports of sections 124 , thereby regulating the flow of molten cathode material fed into multiple slot die 105 . The motion of tubular rams 130 is control by either a hydraulic motor or an electric motor (not shown) capable of exact positioning of the tubular rams 130 relative to exit ports of sections 124 . The electric or hydraulic motor is connected to a control system that regulates the debit of molten cathode material discharged by multiple slot die 105 .
Co-extrusion apparatus 100 comprises a second pair of inner passageways 140 and 142 linking the exit ports of extruders 104 and 108 to multiple slot die 105 . The path of passageways 140 and 142 leads the polymer electrolyte separator material toward the outer portions of multiple slot die 105 on each side of current collector 154 , such that a sheet of polymer electrolyte material will be laid onto the previously laid cathode sheets on each side of current collector 154 . Inner passageways 140 and 142 each comprise two distinct sections identical to inner passageways 120 and 122 and tubular rams 144 adapted to regulate the debit of molten polymer electrolyte material discharged by multiple slot die 105 .
As shown in FIG. 3 , which is a cross-sectional view of multiple slot die 105 , multiple slot die 15 comprises a central channel 160 that guides current collector sheet 154 toward the discharge end of multiple slot die 105 . Multiple slot die 15 comprises four flow channels 162 , 164 , 166 and 168 , each shaped as fish tails, coat hangers or any other flow channel designs known to those skilled in the art of die making to reconfigure the flow of extruded materials into a thin films. Flow channels 162 and 164 aligned with passageways 120 and 122 reshape and discharge the molten cathode material as thin film onto each side of current collector 154 . Flow channels 166 and 168 aligned with passageways 140 and 142 reshape and discharge molten polymer electrolyte material as thin film onto the previously laid cathode material thin films.
Each flow channel 162 , 164 comprises a discharge opening 170 calibrated to discharge a cathode thin sheet of about 20 to 80 μm (depending on end use) directly onto the moving current collector 154 . Each flow channel 166 , 168 comprises a discharge opening 172 positioned downstream from discharge openings 170 and calibrated to discharge an electrolyte separator thin sheet of about 10 to 50 μm (depending on end use) onto the previously laid cathode sheets. The discharge openings 170 and 172 may be calibrated during machining of die 105 or manually adjustable. Adjustments of discharge openings 170 and 172 may be incorporated into the design of multiple slot die 105 as is well know in the art of die making.
As shown in FIG. 2 , a bi-face assembly 155 electrolyte/cathode/current collector/cathode/electrolyte emerges from discharge nozzle 175 and immediately passes between a pair of flat cylinder rollers 180 and 182 driven at constant speed, moving bi-face assembly 155 at a set speed. As previously described and illustrated in FIG. 1 , flat cylinder rollers 180 and 182 are mounted on pivotal support structure 184 and 186 , each having a hydraulic cylinder 188 adapted to adjust the exact position of the cylinder rollers 180 and 182 and the pressure applied onto bi-face assembly 155 as it passes between the cylinder rollers 180 and 182 . It is understood that other means and constructions for adjusting the position of the cylinder rollers 180 and 182 and the pressure applied on the bi-face assembly 155 by the cylinder rollers 180 and 182 are contemplated and within the reach of a person skilled in the art and as such are within the scope of the present invention. The pressure applied by cylinder rollers 180 and 182 helps promote adhesion of the various layers of bi-face assembly 155 together. To prevent adhesion of the electrolyte separator layer of bi-face assembly 155 to flat cylinder rollers 180 and 182 , each cylinder roller may be maintained at temperatures below the ambient temperature and preferably at a temperature ranging from −40° C. to 10° C. Alternatively, each cylinder roller is provided with an anti-adhesive liner.
Co-extrusion apparatus 100 may be equipped with a turret (not shown) comprising two or more multiple slot dies 105 , such that rotation of the turret wilt align a new multiple slot die 105 with the exit ports of passageways 120 , 122 , 140 , 142 . In this embodiment, the extrusion process and the current collector are stopped for a few seconds so that the rotation of the turret cuts the current collector sheet 154 at the exit end 116 of co-extrusion apparatus 100 . The cut end of current collector sheet 154 is fed though central channel 160 and reinserted between cylindrical rollers 180 and 182 such that co-extrusion may resume with minimal delay. The discarded die is removed from the turret and a newly calibrated or adjusted die installed in its stead without undue interruption of production.
As previously described for the co-extrusion of a monoface assembly illustrated in FIG. 1 , a polypropylene thin film 156 shown in dotted lines may be added on each side of the bi-face assembly 155 to protect the electrolyte separator layers. The polypropylene thin films 156 are removed prior to lamination of anode films on each side of the bi-face assembly 155 as described in U.S. Pat. No. 5,100,746, which is hereby incorporated by reference in its entirety. Although not necessary, when bi-face assembly 155 is brought directly to a further processing station where an anode film is laminated on each side of bi-face assembly 155 , the polypropylene thin films 156 are important for storing bi-face assembly 155 into rolls for future use.
As illustrated in FIG. 4 , bi-face assembly 155 winds through a series of rollers 190 to maintain a set tension on the continuous sheets and is brought to a measuring station 192 comprising a series of mechanical, optical, ultra sonic, Gamma or Beta measuring devices to control the thickness of the various layers of bi-face assembly 155 . In this particular embodiment, there are four layers to be measured; the cathode sheets on both sides of current collector 154 and the electrolyte separator sheets laid over each cathode sheets. Therefore, measuring station 192 comprises five measuring devices 194 , 195 , 196 , 197 and 198 . The first measuring device 194 measures the overall thickness of the entire bi-face assembly 155 , including current collector 154 , the two cathode sheets, the two electrolyte separator sheets and, optionally, the two polypropylene films 156 . Note that current collector 154 and, when used, polypropylene sheets 156 are known quantities.
The second measuring device 195 is for example an optical device calibrated to measure the thickness of electrolyte separator sheet on a first side of bi-face assembly 155 . A light wave is sent though the electrolyte layer at an angle; a portion of the light wave is reflected off the first surface of electrolyte layer and a portion of the Light wave is transmitted through electrolyte layer and is reflected by the second surface of electrolyte layer. The two light reflections are received by optical measuring device 195 , which calculates the perpendicular thickness of electrolyte layer. If a polypropylene sheet 156 is used, the light reflected off its surfaces may be discarded. The third measuring device 196 is an ultra sonic, Gamma or Beta device calibrated to measure the thickness of cathode layer on the first side of bi-face assembly 155 . Because the cathode material is opaque, ultra sonic Gamma or Beta waves are better suited to measure its thickness.
The fourth measuring device 197 is a device calibrated to measure the thickness of electrolyte separator sheet on the second side of bi-face assembly 155 and is identical to measuring device 195 . The fifth and last measuring device 198 is a device calibrated to measure the thickness of cathode layer on the second side of bi-face assembly 155 and is identical to measuring device 196 .
Measuring devices 194 , 195 , 196 , 197 , and 198 are individually linked to an electronic control unit, such as a computer, which is continuously fed data representative of the thickness of each cathode layers and each electrolyte layers. This data is monitored by comparing it to pre-set thickness tolerances. When a thickness measurement fall outside the pre-set tolerances, an alarm signal is sent and the multiple slot die 105 is either adjusted manually by a machine operator or replaced. The electronic control unit also monitors trends in the thickness measurements data received. The electronic control unit is linked to the system controlling the debit of molten material through the various passageways 120 , 122 , 140 , and 142 via the motors controlling the position of both tubular rams 130 and 144 , and to the system controlling the speed and pressure of cylindrical roller 180 and 182 . The debit of cathode and electrolyte material may also be adjusted directly at the extruder's level by marginally increasing or decreasing the flow rate by adjusting the throughput of the extruder(s) pumping device(s). The variables of debit, speed and pressure of rollers may be adjusted according to signals received from the electronic control unit with the effect of providing minor adjustments to the thickness of the electrolyte layers and of the cathode layers of assembly 155 . As previously mentioned, other means of controlling the debits of cathode material and electrolyte material other than the illustrated tubular rams are possible and contemplated and within the competence of the skilled technician. Examples of such means are numerous and include gear pumps adjustments, valves and adjustable restrictions of the passageways or exit ports 116 or even at the die exit.
FIG. 5 illustrates another variant of the invention, where two extrusion stations 201 and 203 are positioned adjacent one another along the path of a current collector 205 . Extrusion station 201 is adapted to lay directly onto current collector 205 a first layer of extruded cathode material 210 on both sides of current collector 205 . Extrusion station 201 comprises two extruders 212 and 213 mixing and extruding thin films of cathodic material as illustrated, but could easily comprise only one extruder with two feeding ports. Extruders 212 and 213 feed extruded cathodic material through an extrusion die 215 comprising a pair of flow channels 216 and 217 shaped as fish tails or coat hangers or any other shape that reconfigures the flow of extruded materials into a thin films. Flow channels 216 and 217 reshape the flow and discharge extruded cathode material as thin film onto each side of current collector 205 . The flow channels are provided with thickness adjustment means 219 and 220 adapted to adjust the thickness of the cathode sheets being laid onto current collector 205 . Adjustment means 219 and 220 are illustrated as mechanical but may also be hydraulically or electrically controlled. A primary assembly 218 comprising current collector 215 and two cathode sheets 210 exits die 215 and is compressed by a first pair of rollers 222 before entering second extrusion station 203 through an aperture 224 adapted to receive the marginally thicker primary assembly 218 .
Extrusion station 203 is adapted to lay directly onto primary assembly 218 a second layer of extruded polymer electrolyte material 226 on both sides of primary assembly 218 . Extrusion station 203 also comprises two extruders 230 and 232 mixing and extruding thin films of polymer electrolyte material as illustrated, but could easily comprise only one extruder with two feeding ports. Extruders 230 and 232 feed extruded polymer electrolyte material through an extrusion die 235 similar to extrusion die 215 , although adjusted for primary assembly 218 . Extrusion die 235 comprises a pair of flow channels 236 and 237 shaped as fish tails or coat hangers, which reconfigure the flow of extruded materials into a thin film. Flow channels 236 and 237 reshape the flow and discharge extruded polymer electrolyte material as thin film onto each side of primary assembly 218 . The flow channels are provided with thickness adjustment means 219 and 220 adapted to adjust the thickness of the extruded electrolyte sheets being laid onto primary assembly 218 . A multi-layer assembly 240 comprising current collector 215 , two cathode sheets 210 and two polymer electrolyte sheets exits extrusion die 235 and is compressed by a second pair of rollers 242 to complete the bi-face current collector/cathode/electrolyte separator laminates.
In this particular embodiment, the co-extrusion process may be carried out while the current collector is traveling upwardly. Advantageously when the various layers are deposited onto a sheet of current collector traveling vertically in the upward direction, the extruded cathode and electrolyte materials are spread more evenly due to the equal action of gravity on each layer pulling down on the extruded material.
As in previously described embodiments, the co-extrusion apparatus illustrated in FIG. 5 may be complemented with mechanical, optical, ultra sonic, Gamma or beta measuring devices adapted to measure the thickness of the various layers. In this specific embodiment, two such measuring stations would be provided immediately after each co-extrusion apparatus 201 and 203 , so that the initial measurement of the extruded cathode layers 210 is taken without the interference of the electrolyte layers 226 . One or two electronic units such as computers receive the measurement data and adjust the extruders' flow rates, the thickness of the extruded sheets via adjustment means 219 and 220 and the pressure exerted by cylindrical rollers 222 and 242 in order to provide minute adjustments of the thickness of the various layers 210 and 226 .
FIG. 6 illustrates another variant of a co-extrusion process and apparatus, in which two co-extrusion apparatuses 301 and 302 similar to co-extrusion apparatus 10 illustrated in FIG. 1 are positioned on each sides of a moving current collector 305 . Each co-extrusion apparatus 301 and 302 comprises a double slot die 315 having a pair of flow channels 316 and 317 . Flow channels 317 extrude thin sheets of cathode material directly onto each side of current collector 305 , whereas flow channels 316 extrude a thin sheet of polymer electrolyte material over the previously laid cathode thin sheets. The discharge section of each double slot die 315 is angled relative to current collector 305 such that the extruded cathode sheets are properly laid first and then the electrolytes sheets are laid over the cathode sheets. Two cylindrical rollers 320 positioned directly after co-extrusion apparatus 301 and 302 apply a small pressure directly onto the surfaces of the electrolyte layers. As previously mentioned, the co-extrusion may be carried out with current collector 305 traveling vertically upward.
As in previously described embodiments, the co-extrusion apparatus illustrated in FIG. 6 may be complemented with precise measuring devices adapted to measure the thickness of the various layers. In this specific embodiment, a single measuring stations would be provided immediately after each co-extrusion apparatus 301 and 302 , that measures the thickness of each extruded cathode layers and each electrolyte layers. One electronic unit such as computers receives the measurement data and adjust the extruders' speeds, the thickness of the extruded sheets via internal debit adjustment means (not shown) and the pressure exerted by cylindrical rollers 320 in order to provide minute adjustments of the thickness of the various extruded layers.
FIG. 7 illustrates yet another variant of a co-extrusion process and apparatus, in which four extrusion apparatus 401 , 402 , 403 and 404 are positioned in pairs on each side of a moving current collector 406 . The first pair of extrusion apparatuses 401 and 402 extrude a thin sheet of cathode material 410 directly onto each surface of current collector 406 . These first layers 410 passes through a first pair of cylindrical rollers 412 , which apply an even pressure onto cathode layers 410 to adjust their thickness. The first assembly 414 consisting of cathode/current collector/cathode is then fed through the second pair of extrusion apparatus 403 and 404 extrude directly onto each surfaces of cathode layers 410 a thin sheet of electrolyte material 416 . The final assembly 418 consisting of electrolyte/cathode/current collector/cathode/electrolyte is then fed through a second pair of cylindrical rollers 420 , which apply an even pressure onto final assembly 418 to adjust the final thickness of the extruded assembly. As mentioned, the co-extrusion may be carried out with current collector 406 traveling vertically upward.
As in the previously described embodiment of FIG. 5 , the co-extrusion apparatus illustrated in FIG. 7 may be complemented with measuring devices adapted to measure the thickness of the various layers. In this specific embodiment, two such measuring stations would be provided immediately after each pair of extrusion apparatus, so that the initial measurement of the extruded cathode layers 410 is taken without the interference of the electrolyte layers 416 . One or two electronic units such as computers receive the measurement data and adjust the extruder's speeds, the thickness of the extruded sheets via internal adjustment means of each extrusion apparatus 401 , 402 , 403 , and 404 , and the pressure exerted by cylindrical rollers 412 and 420 in order to provide minute adjustments of the thickness of the various layers 410 and 416 .
FIG. 8 illustrates yet another variant of a co-extrusion process and apparatus in which two co-extrusion apparatus 501 and 502 similar to co-extrusion apparatus 10 illustrated in FIG. 1 are positioned on opposite sides of a moving current collector 505 . Current collector 505 winds its way through a series of rollers that effectively turn the current collector upside down such that co-extrusion apparatus 501 coats one side of the current collector 505 and co-extrusion apparatus 502 coats the other side of the current collector 505 . Each co-extrusion apparatus 501 and 502 comprises a double slot die 515 having a pair of flow channels 516 and 517 . Flow channels 517 extrude thin sheets of cathode material directly onto each side of current collector 505 , whereas flow channels 516 extrude a thin sheet of polymer electrolyte material over the previously laid thin sheets of cathode material. In operation, current collector 505 is initially re-directed by cylindrical roller 510 toward cylindrical roller 512 and co-extruder 501 . Co-extruder 501 discharges a thin layer of cathode material 520 directly onto the current collector 505 and a thin layer of a polymer electrolyte material 521 directly onto the layer of cathode material 520 through the flow channels 516 and 517 of its double slot die 515 as the current collector 505 is supported by roller 512 . The assembly of current collector 505 , cathode layer 520 and polymer electrolyte layer 521 remains in contact with roller 512 for approximately ½ turn or 180°, and is directed through cylindrical rollers 511 and 513 and toward the nip of cylindrical roller 518 and co-extruder 502 with the current collector 505 facing the double slot die 515 of co-extruder 502 . Co-extruder 502 discharges a thin layer of cathode material 522 directly onto the current collector 505 and a thin layer of a polymer electrolyte material 523 directly onto the layer cathode material 522 as the assembly is supported by roller 518 . The bi-face half cell assembly of electrolyte 523 /cathode 522 /current collector 505 /cathode 520 /electrolyte 521 is then completed and either appropriately stored for future processing or directed to a subsequent manufacturing station for further processing. Cylindrical rollers 513 and 518 may be cooled and kept at a low temperature to prevent the polymer electrolyte layer 521 from undesirably adhering thereto. As previously described for co-extrusion apparatus 301 and 302 , the discharge section of each double slot die 515 of co-extruder 501 and 502 may be angled relative to current collector 505 and its trajectory such that the extruded cathode layers 520 and 522 are appropriately laid first and then the polymer electrolyte layers 521 and 523 are suitably laid over the cathode sheets or layers 520 and 522 . Nip rollers may also be positioned directly after co-extruders 501 and 502 to apply small pressure directly onto the surfaces of previously laid cathode and electrolyte layers to promote adhesion and surface leveling.
As described for the previous embodiments, the co-extrusion apparatus illustrated in FIG. 7 may be complemented with measuring devices adapted to measure the thickness of the various layers of the assembly.
Although the present invention has been described in relation to particular variations thereof, other variation and modifications are contemplated and are within the scope of the present invention. Therefore the present invention is not to be limited by the above description but is defined by the appended claims.
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A process of co-extrusion of a thin electrode sheet with a thin electrolyte polymer sheet directly onto a current collector sheet for a lithium polymer battery. The process includes the steps of:
(a) mixing a polymer with active electrode material, lithium salt and electronic conductive material in a first mixing chamber to form an electrode slurry; (b) mixing a polymer with a lithium salt in a second mixing chamber to form an electrolyte slurry; (c) feeding the electrode slurry through a first flow channel and the electrolyte slurry through a second flow channel; (d) extruding the electrode slurry in the form of a thin electrode sheet through a first die opening connected to the first flow channel, the electrode slurry being extruded directly onto a current collector sheet; and (e) concurrently extruding the electrolyte slurry in the form of a thin electrolyte sheet through a second die opening adjacent to the first die opening and connected to the second flow channel, the thin electrolyte sheet being extruded directly onto the thin electrode sheet.
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BRIEF SUMMARY OF THE INVENTION
This invention relates to sorting, and in particular to a sorting apparatus for taking in articles or other materials at an intake port and distributing the articles selectively to different discharge ports.
Sorting equipment of the type to which this invention relates finds utility in many applications, including manufacturing plants, warehouses, etc.
Prior sorters fall generally into two categories. One type of sorting apparatus which is employed frequently is the two-dimensional sorter in which a large number of sorting conveyors branch out from an intake conveyor toward different discharge ports. All of the sorting conveyors are disposed in the same plane. Another type of sorting apparatus is the rotary rack sorter, which employs a large number of multi-level racks circulating in a horizontal path along rails. Articles at the different levels on a rack are selectively discharged at specified discharge stations along the path of travel of the rack.
The two-dimensional sorter requires a large floor area, and the floor area required depends on the number of article destinations. Furthermore, with a given two-dimensional sorter, it is difficult to provide additional destinations.
With the rotary rack sorter, it is possible to provide for additional article destinations by providing additional levels on the racks. Therefore, no additional floor area is required. However, the rotary rack sorter has the drawback that, when an article is taken in, it must be placed in a selected rack level corresponding to the desired destination. Thus, selection is required at the intake station of the apparatus. Because of the requirement for selection of rack levels at the intake stage, complicated measures must be taken to insure proper timing at the intake station in order to avoid errors.
The general object of the invention is to provide a sorting apparatus which avoids the foregoing problems of the prior art.
A more specific object of the invention is to provide a simple and reliable sorting apparatus which has the ability to route articles toward a large number of selectable destinations, and which does not require an excessively large floor area.
It is also an object of the invention to provide a simple and reliable sorting apparatus in which additional destinations can be easily provided without increasing floor area requirements.
The invention addresses the foregoing problems by taking in all articles at the same level at an intake station, and discharging each article at a selected one of several available discharge levels at a selected one of several discharge stations More particularly, the sorting apparatus in accordance with the invention comprises a plurality of frame members; rail means arranged to support the frame members for circulating movement in a closed path; tray means carried by each frame member; means on each frame member for guiding the tray means carried thereby for up and down movement relative to the frame member; a first guide rail extending along a first part of the closed path and having an exit end; a plurality of secondary guide rails extending around a second part of the closed path at different levels, each secondary guide rail having an intake end; an array of change-over rails situated between the exit end of the first guide rail and the intake ends of the secondary guide rails, with the change-over rails being arranged to move vertically to connect the exit end of the first guide rail selectively to the intake end of any one of said secondary guide rails; controllable means for effecting vertical movement of the change-over rails; and follower means connected to each of the tray means, and guidable by the guide rails and the change-over rails to control the level of the tray means as they travel along the closed path. As the follower of each tray means reaches the change-over rails after being guided by the first guide rail along the first part of the closed path, it is selectively moved to any one of a plurality of different levels for travel along the second part of the closed path. Thus the discharge level is selected by operation of the change-over rails. Discharge of a tray-carried article at the discharge level is carried out by discharge assisting means at a selected one of several discharge stations.
Each of the trays has a unique number assigned to it. When an article is taken in on one of the trays a number representing the specified destination of the article is associated with the tray number in a computer. This is accomplished by entering the information manually on a keyboard, or by means of a bar code reader, voice recognition equipment, or other suitable means. As the tray moves along the first guide rail, and before it reaches the change-over rails, the computer instructs the change-over rails to connect the exit end of the first guide rail to the intake end of the secondary guide rail which will guide the tray to the specified destination port. The tray is transferred from the first guide rail to the selected secondary guide rail by way of one of the change-over rails. It is then transported along the selected secondary guide rail until it reaches the designated destination port, where the article on the tray is discharged by discharge assisting means under control of the computer.
Further objects, details and advantages of the invention will be apparent from the following detailed description when read in conjunction with the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a front elevation of a sorting apparatus in accordance with the invention;
FIG. 2 is a top plan view of the same;
FIG. 3 is a fragmentary perspective view illustrating the essential parts of the invention;
FIG. 4 is a fragmentary elevational view illustrating a first embodiment of a discharge assisting means in accordance with the invention;
FIG. 5 is a fragmentary elevational view illustrating a second embodiment of a discharge assisting means in accordance with the invention;
FIG. 6 is a fragmentary front elevation illustrating details of the change-over rail operating mechanism; and
FIG. 7 is a front elevational view of a conventional rotary rack sorter.
DETAILED DESCRIPTION
Referring briefly to FIG. 7, the conventional rotary rack sorter comprises a large number of rack frames F which are supported between an upper annular rail G and a lower annular rail R for circulating movement in a closed path. Each rack has a number of levels T. Typically, each of the discharge stations along the path of the rack frames has multiple discharge ports, so that articles discharged from different levels at a discharge station may go to different destinations. Thus, when an article is to be taken in on a rack frame, it will ordinarily be necessary to place it at a particular selected level T. With the invention, however, all articles are taken in at the same level.
Referring to FIGS. 1, 2 and 3, the sorting apparatus comprises a large number of transporting frames arranged to circulate in an elongated, closed path. A typical frame 1 comprises two upright guide posts la and lb. The frame has wheels which travel on a lower rail 2 and guide wheels which are guided by an upper rail 3. Adjacent frames are connected together by links 4.
As shown in FIGS. 2 and 3, a driving sprocket D at one end of the apparatus meshes with the upright guide posts of the individual frames, and is driven by motor M to effect movement of the frames along rails 2 and 3. An idler F guides the frames as they move around the opposite end of the apparatus.
As shown in FIGS. 1 and 3, a tray supporting member 5 is provided on each frame and mounted for up and down sliding movement on the upright guide posts of the frame. Each tray supporting member is provided with a rearwardly projecting wheel 5a, as seen in FIG. 3, for following the guide rails. In FIG. 3, wheel 5a is shown following a first guide rail 6, which serves to maintain the tray support at a predetermined level as it passes a take-in station.
The first guide rail 6 extends along a first part of the closed path of the circulating frames, and secondary guide rails 7a, 7b and 7c extend, at separate levels, along a second part of the closed path. Change-over rails 8a, 8b and 8c are situated between the exit end of guide rail 6 and intake ends of secondary guide rails 7a, 7b and 7c. As best shown in FIG. 3, these change-over rails are mounted on a lifting frame 9, which is movable up and down for connection of rail 6 to any selected one of rails 7a, 7b and 7c. Thus, with the change-over rails in the condition shown in FIG. 3, rail 6 is connected by change-over rail 8b to intermediate secondary rail 7b. If frame 9 is moved downward, rail 6 can be connected to upper secondary rail 7a. If frame 9 is moved upward, rail 6 can be connected to lower secondary rail 7c. As the frame moves past the change-over rails, the guide wheel 5a of its tray support is guided by one of rails 8a, 8b and 8c onto one of rails 7a, 7b and 7c respectively. The level of the tray support is controlled accordingly.
In the operation of the apparatus described thus far, a unique number associated with each transporting frame is associated in a control computer (not shown) with frame position information generated by an encoder E associated with motor M and drive sprocket D (FIGS. 2 and 3). Destination information is entered into the computer as each article is placed on a tray at an intake station along guide rail 6, preferably by means of a bar code reader. The destination information includes not only the location of the exit station along the path of travel of the transporting frames, but also the level of the destination port. The latter information determines which of the secondary guide rails is selected.
Accordingly, by way of example, when the destination of an article is on the upper level at a particular discharge station, the upper level and the location of the discharge station are both identified to the computer when the article is placed on a tray at the intake station. When the tray supporting member carrying that article approaches the change-over rails, the computer directs the change-over control to lower frame (if it is not already lowered) so that rail 6 is connected by change-over rail 8a to secondary rail 7a. Consequently, the article is carried toward its designated discharge station at the upper level corresponding to guide rail 7a.
When the tray supporting member reaches the selected discharge station, it is opposite the discharge port associated with upper rail 7a at that station. The control computer then causes a discharge assisting device to discharge the carried article through the discharge port.
In FIG. 4, which shows one form of discharge assisting device, a tray 5b is mounted pivotally on a tray supporting member 5. This tray is normally urged by its own weight, or by the weight of a carried article, to tilt forward in a load discharging direction. The follower wheel 5a of the tray support member 5 is guided in upper secondary rail 7a. The tray is normally prevented from pivotal motion in the discharging direction by a latching lever 5c, which is also pivotally mounted on tray support member 5 and engaged with a hook on the underside of the tray. Rod 11 is movable in the vertical direction by an actuator which operates in response to an operating instruction from the controlling computer. Rod 11 is located opposite a discharge station, and has a roller 11a arranged to tilt latching lever 5c so that it disengages the hook, allowing the tray to tilt forward to the position indicated by the broken lines, and discharge its contents through a discharge port.
Rod 11 also has roller 11b, which is adapted to engage latching lever 5c if the follower wheel is guided in intermediate secondary rail 7b. A similar roller (not shown) is provided on rod 11 to unlatch a tray guided along the lower secondary rail.
In FIG. 5, which shows another form of discharge assisting device, an article discharge conveyor 12 is mounted on tray support member 5. A rod 15, located opposite a discharge station, is movable back and forth horizontally by an actuator 14 in response to a instructions issued by the control computer. The rod carries a toothed rack 15a, which is engageable with a pinion 16 arranged to drive discharge conveyor 12 through a drive shaft 13 by way of bevel gears 17a and 17b. When the tray support 5 approaches a discharge port opposite secondary guide rail 7a, rack 15a may be advanced by actuator 14 to mesh with pinion 16. This causes the article-supporting face of discharge conveyor 12 to move forward, in the direction indicated by the arrow, to discharge the carried article.
FIG. 5 also shows a second rack 15b on rod 15, for effecting discharge of articles from a discharge conveyor travelling at the intermediate level. A similar third rack (not shown) is provided for discharging articles from a conveyor travelling at the lower level.
As shown in FIG. 6, the change-over rails 8a, 8b and 8c are fixed relative to one another on frame 9. Frame 9 is provided with slides 19 which cooperate with fixed upright posts 18a and 18b. These slides are movable up and down by actuators Cl and C2 operating in response to instructions from the controlling computer. Limit switches, including switches LS1 and LS2 are provided to insure proper registration of the change-over rails with guide rails 6, 7a, 7b and 7c.
Referring again to FIG. 2, articles to be sorted are carried in on conveyor 20 and moved past a bar code reader 10 as they are placed on trays at intake station A. If a destination of an article is read by the bar code reader, the destination of the tray on which the article has been placed is automatically specified. When that tray approaches the change-over rails, the controlling computer issues an instruction causing frame 9 to move, if necessary, causing the change-over rails to connect guide rail 6 to the secondary rail 7a, 7b or 7c which extends past the discharge port corresponding to the specified destination. Consequently, the tray advances along the specified secondary rail, and approaches a specified discharge station of stations B 1 , B 2 , B 3 , . .B n . The discharge assisting device (lifting rod 11 in FIG. 4 or rack carrying rod 15 in FIG. 5) is operated to discharge the article into one of boxes 21a, 21b, . . .21 n , which will ultimately be carried out on conveyor 22. Ordinarily, but not necessarily in all cases, there will be multiple levels of article-receiving boxes at each discharge station.
After passing the last discharge station B n , the tray support 5 is returned to rail 6 by suitable guide rail sections (not shown), or a set of change-over rails similar to change over rails 8a, 8b and 8c. After return to rail 6, the tray support is ready to take on another article.
After leaving the last discharge station B n , but before reaching intake station A, a discharging operation is performed at the location of box 23 to insure that the trays arriving at intake station A are empty. This supplementary discharging operation is carried out by a discharge assisting mechanism such as that shown in FIGS. 4 or 5. Accordingly, even if an article should remain on a tray passing discharge station B n due to an error in the sorting and discharging operations, it will be discharged into box 23. In the case of the tilting tray of FIG. 4, if necessary, cam means (not shown) may be provided, at a position between the supplementary discharge station and intake station A, to reset the tray to its latched position.
It will be apparent from the foregoing that the sorting apparatus of the invention is capable of distributing materials a large number of destinations, and yet does not occupy a large amount of floor space.
Since the change-over rail mechanism operates in response to an instruction from a controlling computer in accordance with a unique number corresponding to each tray, it is unnecessary, when loading an article onto the sorting apparatus, to select a particular tray for carrying an article to its designated destination, as is the case with a conventional rotary rack sorter. Furthermore, an article remains on its own tray during change-over from rail 6 to rails 7a, 7b and 7c. Accordingly, the possibility of error is substantially eliminated, and control of the apparatus is greatly simplified. In addition, since the articles remain on their own trays, articles of many different shapes can be sorted precisely and smoothly.
The apparatus as described herein can be modified in a number of respects. For example, while three secondary rails are shown, it is possible to realize many of the advantages of the invention in sorters having two, or four or more secondary rails. Other forms of discharge assisting devices, such as pushers, can be substituted for the latch and rack mechanisms shown in FIGS. 4 and 5. Numerous other modifications may be made to the apparatus described without departing from the scope of the invention as defined in the following claims.
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A three dimensional sorting apparatus utilizes a plurality of frame members, supported for circulating movement in a closed path. A tray is mounted for up and down movement on each of the frame members and is guided along rails which determine its height. Change-over rails, controlled to move up and down, are provided to connect a first guide rail extending past an intake station to a selected one of a plurality of secondary guide rails extending at different levels past a plurality of discharge stations. This enables an article to be discharged into a selected one of several discharge ports at a selected discharge station. Discharge is carried out by pivoting the tray forward upon release of a tray-retaining latch by a discharge assisting device at each discharge station. Alternatively, the article is carried on a conveyor driven by a pinion which is activated by a discharge assisting rack at each discharge station.
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CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation application of a pending US patent application entitled “POWER FACTOR CORRECTION DEVICE AND CORRECTING METHOD THEREOF” application Ser. No. 13/408,077, filing date: Feb. 29, 2012, inventor Chung-Ping Ku (attorney docket# APOM070). The above contents are incorporated herein by reference for any and all purposes.
FIELD OF THE INVENTION
[0002] The invention relates to power factor correction (PFC) devices, in particular to a power factor correction device for PFC Boost converters.
BACKGROUND OF THE INVENTION
[0003] Nowadays, high-quality power supplies with increasing energy efficiency are in high demand. Power factor correction technique plays an important role in improving the electric power supply efficiency of electric appliances, which are usually inductive loads that cause the current and voltage out of phase leading to low energy efficiency. A power factor corrector synchronizes the phases of the input voltage and the input current of an electric appliance, namely, the load of the electric appliance is adapted similar to a resistance-type load, thus harmonic distortion of the input current is effectively reduced resulting in high power factor of power supply.
[0004] A common power factor correction device requires a pulse width modulation (PWM) signal generator to provide a pulse width modulation (PWM) signal and a sample of an input voltage as a reference signal for correcting the current. In the conventional technologies, for example, the pulse width modulation signal generator disclosed by U.S. Pat. No. 5,886,586 does not require the input voltage sample but uses an integrator to perform one-cycle (i.e., feed-forward) control method to decide charge-discharge time and electric potential of an integrated capacitor. Other US patents, such as U.S. Pat. Nos. 7,068,016 and 5,804,950, also disclose similar technologies. However, the above patents using the integrator or the integrated capacitor in or out of a circuit, as such the response speed of the internal circuit is greatly reduced during the operation. In addition, the circuit is internally provided with a switch for discharging the integrated capacitor; therefore, power consumption is increased and the circuit space is enlarged.
[0005] Hence, the invention provides a power factor correction device and a correcting method thereof to solve the above problems.
SUMMARY OF THE INVENTION
[0006] The present invention provides a power factor correction device and a correcting method. The current compensating circuit and the voltage compensating circuit are connected to a multiplier to multiply the compensating voltage signal by the compensating current signal to generate an updated reference current signal. The updated reference current signal is provided to the current compensating circuit to perform power factor correction. The device and method of the present invention can avoid the use of the integrated capacitor, therefore the response speed of the internal circuit is greatly increased during operation, thus power factor correcting efficiency is improved.
[0007] To achieve the above purpose, the present invention provides a power factor correction device, which comprises a power stage circuit. The power stage circuit, which is connected to a load, receives an input alternating current (AC) voltage and a pulse width modulation signal. The input alternating current voltage is converted into an input current in accordance with the pulse width modulation signal via the inductor, the power diode and the power transistor, which are driven by the pulse width modulation signal. The input current is output to the load, which produces an output voltage on the load. The power stage circuit samples the input current through the sample resistor as a correcting current. The power stage circuit is connected to the current compensating circuit that receives error between the correcting current and the reference current signal, thus a compensating current signal is generated through the current error amplifier and the current compensator. The power stage circuit is also connected to the voltage compensating circuit and the error between the output voltage and a reference voltage is received by the voltage divider, thus, a compensating voltage signal is generated by the voltage error amplifier and the voltage compensator. The outputs of the current compensating circuit and the voltage compensating circuit are connected with a multiplication amplifier that receives the compensating current signal and the compensating voltage signal, thus an updated reference current signal is generated after multiplying the compensating current signal by the compensating voltage signal. The current compensating circuit and the voltage compensating circuit are connected to a pulse width modulation converter that receives the compensating current signal and the compensating voltage signal to generate the updated pulse width modulation signal and to obtain the same phases of the alternating current voltage and the input current.
[0008] The present invention also provides a power factor correcting method. First the correcting current and output voltage is compared to a reference current signal and a reference voltage respectively generating a compensating current signal and a compensating voltage signal through the current compensating circuit and the voltage compensating circuit, as such an updated pulse width modulation signal is generated and same phases of the alternating voltage and the input current are obtained. An updated reference current signal is obtained by multiplying the compensating current signal with the compensating voltage signal through the multiplication amplifier. Finally, the updated pulse width modulation signal is generated from the compensating current signal and the compensating voltage signal and the same phases of the alternating current voltage and the input current are achieved.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] As shown in attached drawing, the embodiment of the invention is more sufficiently described. However, the attached drawing is only used for explanation and illustration rather than limitation to the scope of the invention.
[0010] FIG. 1 is a circuit schematic diagram of the power correction device of the present invention.
[0011] FIG. 2 is a block diagram for the transfer function of the power correction device of the present invention.
[0012] FIG. 3 is a flow diagram of the correcting method of the present invention.
[0013] FIG. 4 is a waveform diagram of all received and generated signals in power correction device of the present invention.
[0014] FIG. 5 is an amplified waveform diagram of the reference current signal, the compensating current signal and the compensating voltage signal of FIG. 4 .
[0015] FIG. 6 is a waveform diagram of the ramp signal, the compensating current signal and the pulse width modulation signal.
[0016] FIG. 7 is a waveform diagram of the 220V alternating current voltage and its input current achieved by the power correction device of the present invention.
[0017] FIG. 8 is a waveform diagram of the 110V alternating current voltage and its input current achieved by power correction device of the present invention.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0018] As shown in FIG. 1 , the power factor correction device of the invention includes a power stage circuit 12 connected to a load 10 . The power stage circuit 12 receives an alternating-current (AC) voltage V AC and a pulse width modulation signal V PWM , then, the alternating-current (AC) voltage V AC is converted into an input current I AC in accordance with the pulse width modulation signal V PWM . The input current I AC is fed to the load 10 to generate an output voltage V o on the load 10 . The input current I AC is also sampled as a correcting current I sen . The power stage circuit 12 is connected to a current compensating circuit 14 and a voltage compensating circuit 16 . The current compensating circuit 14 receives and compares the correcting current I sen with a reference current signal I ref to generate a compensating current signal I EA . The voltage compensating circuit 16 receives and compares the output voltage V o with a reference voltage V ref to generate a compensating voltage signal V EA . Both of the current compensating circuit 14 and the voltage compensating circuit 16 are connected to a multiplication amplified 8 and a pulse width modulation converter 20 . The multiplication amplifier 18 receives and multiplies the compensating current signal I EA with the compensating voltage signal V EA to generate an updated reference current signal I ref . The pulse width modulation converter 20 receives the compensating current signal I EA and the compensating voltage signal V EA to generate an updated pulse width modulation signal V PWM , thus same phases of the alternating current voltage V AC and the input current I AC is obtained.
[0019] The power stage circuit 12 includes a sample resistor 22 and an alternating-current/direct-current (AC/DC) converter 24 . The AC/DC converter 24 includes an inductor 241 , a power transistor 243 , and a power diode 245 . The sample resistor 22 is connected to the current compensating circuit 14 . The AC/DC converter 24 is connected to the load 10 , the sample resistor 22 , the current compensating circuit 14 and the voltage compensating circuit 16 . The AC/DC converter 24 receives AC voltage V AC and pulse width modulation signal V PWM , then the AC voltage V AC is converted into input current I AC in accordance with the pulse width modulation signal V PWM by inductor 241 , power transistor 243 , and power diode 245 , thus the input current I AC is fed to the load to generate the output voltage Vo. Furthermore, the input current I AC is sampled by the sample resistor 22 to generate the correcting current I sen .
[0020] The current compensating circuit 14 includes a current error amplifier 26 and a current compensator 28 . The current error amplifier 26 connected to the sample resistor 22 of the power stage circuit 12 receives and compares the correcting current I sen and a reference current signal I ref , thus generating a comparing current. The current compensator 28 connected to the current error amplifier 26 receives and compensates the comparing current to generate the compensating current signal I EA . The voltage compensating circuit 16 comprises a voltage divider 30 that is connected to the AC/DC converter 24 of the power stage circuit 12 , receives and divides the output voltage V o to generate a feedback voltage V FB . The voltage divider 30 is connected to a voltage error amplifier 32 that receives and compares the feedback voltage V FB with a reference voltage V ref to generate a comparing voltage. The voltage error amplifier 32 is connected to a voltage compensator 34 that receives and compensates the comparing voltage thus generates a compensating voltage signal V EA .
[0021] The multiplication amplifier 18 includes a multiplier 36 and a current gain regulator 38 . The multiplier 36 is connected to the current compensator 28 of the current compensating circuit 14 and the voltage compensator 34 of the voltage compensating circuit 16 and receives the compensating current signal I EA and the compensating voltage signal V EA to generate a compensating feedback current by multiplying the compensating current signal I EA by the compensating voltage signal V EA . The multiplier 36 is also connected to the current gain regulator 38 that receives the compensating feedback current and generates an updated reference current signal I ref by multiplying the compensating feedback current by a current gain K m .
[0022] The pulse width modulation converter 20 includes a ramp generator 40 that is connected to the voltage error amplifier 32 of voltage compensating circuit 16 and receives the compensating voltage signal V EA to generate a ramp signal V RAMP . Ramp generator 40 and current error amplifier 26 of the current compensating circuit 14 are connected to a conversion comparator 42 that receives and compares ramp signal V RAMP with compensating current signal I EA to generate an updated pulse width modulation signal V PWM that is fed into the AC/DC converter 24 of the power stage circuit 12 . When the voltage value of the ramp signal V RAMP is higher than the corresponding voltage value of the compensating current signal I EA , the updated pulse width modulation signal V RAMP is a high level voltage. Otherwise, when the voltage value of the ramp signal V RAMP is lower than the corresponding voltage value of the compensating current signal I EA the updated pulse width modulation signal V PWM is a low level voltage.
[0023] In order to obtain same phases of the input alternating current voltage and the input current, the sample resistance, the pulse width modulation signal V PWM , the input current I AC , the alternating current voltage V AC , the output voltage V o and the ramp signal V RAMP have to be satisfied the following conditions:
[0000] R S ·i in (θ)= d OFF (θ)· T S.W. ·S V (1)
[0000] d OFF (θ)= V in — pk ·sin(θ)/ V o =1 −d (θ) (2)
[0000] i in (θ)= V in — pk ·sin(θ)/ R in(ac) (3)
[0024] where:
i in (θ) is the input current I AC , V in — pk ·sin(θ) is the alternating current voltage V AC , S V is slope of the ramp signal V RAMP , R in(ac) is equivalent input alternating current resistance, T S.W. and d(θ) are cycle and duty cycle of the pulse width modulation signal V PWM respectively.
Formulas (4) and (5) can be obtained from formulas (1), (2) and (3) as follows:
[0000]
i
n
(
θ
)
=
V
i
n
_
p
k
R
i
n
(
a
c
)
·
sin
(
θ
)
(
4
)
R
i
n
(
a
c
)
=
R
S
·
V
o
T
s
.
w
·
S
V
(
5
)
[0000] From formula (5), R in(ac) is a constant, therefore, the phases of the alternating current voltage and the input current are the same.
[0030] The input power P in , the compensating current signal I EA , the compensating voltage signal V EA , the slope S V of the ramp signal V RAMP , and a peak voltage V pmax of the ramp signal V RAMP are introduced as follows:
[0000]
I
A
C
≅
2
P
i
n
V
A
C
(
6
)
V
EA
≅
2
P
i
n
·
R
S
·
V
o
K
multi
·
V
A
C
2
(
7
)
S
V
≅
V
EA
·
g
mv
C
S
·
T
S
.
W
(
8
)
I
EA
≅
2
P
i
n
·
R
S
·
g
mv
·
T
S
.
W
.
K
multi
·
V
A
C
·
C
S
(
9
)
V
pmax
≅
I
EAmax
V
o
V
A
C
min
(
10
)
Where:
[0031] K multi is multiplication gain of the multiplier 36 ,
[0032] g mv is the gain of the voltage error amplifier 32 ,
[0033] C s is a capacitance value of the interior capacitor of the ramp generator 40 ,
[0034] I EAmax is the largest current value of the compensating current signal I EA , and
[0035] V ACmin is the smallest value of the alternating current voltage.
[0036] An updated reference current signal I ref is obtained by multiplying the compensating current signal I EA by the compensating voltage signal V EA , as follows:
[0000]
1
Z
comp
·
∫
0
π
/
2
(
R
S
·
i
i
n
(
θ
)
-
K
m
·
(
d
OFF
(
θ
)
·
T
S
.
W
.
·
S
V
·
V
o
·
K
v
)
)
θ
=
d
OFF
(
θ
)
·
T
S
.
W
.
·
S
V
⇒
i
i
n
(
θ
)
=
T
S
.
W
.
·
S
V
R
S
[
K
m
(
d
OFF
(
θ
)
·
V
o
·
K
v
)
+
Z
comp
·
θ
·
d
OFF
(
θ
)
]
⇒
i
i
n
(
θ
)
=
T
S
.
W
.
·
S
V
R
S
·
V
i
n
_
p
k
V
o
(
K
m
·
V
o
·
K
v
·
sin
(
θ
)
+
Z
comp
·
cos
(
θ
)
)
⇒
K
m
·
V
o
·
K
v
i
i
n
(
θ
)
=
T
S
.
W
.
·
S
V
·
V
i
n
_
p
k
·
K
m
·
K
v
R
S
·
sin
(
θ
)
⇒
i
i
n
(
θ
)
=
V
i
n
_
p
k
R
i
n
(
a
c
)
·
sin
(
θ
)
⇒
R
i
n
(
a
c
)
=
R
S
T
s
.
w
·
S
V
·
K
m
·
K
v
Where:
[0037] K V is a voltage division proportion of the voltage divider 30 , and
[0038] Z comp is impedance of the current compensator 28 .
[0039] In this invention, a sample of the input voltage is not required and the compensating current signal I EA and the compensating voltage signal V EA are used to acquire an updated reference current signal I ref to achieve the correction of the power factor. The method of the invention can avoid the use of an integrated capacitor, as such the response speed of the internal circuit is greatly increased during operation to improve the power correction efficiency.
[0040] FIG. 2 and FIG. 3 describe a correcting method of the invention. As shown in FIG. 2 , G v(s) is a transfer function of the voltage compensator 34 , G i(s) is the transfer function of the current compensator 28 , G id(s) is the transfer function of the AC/DC converter 24 , and K PWM is the transfer function of the pulse width modulation converter 20 . As shown in step S 10 , the AC/DC converter 24 of the power level circuit 12 receives the input alternating current voltage V AC and the pulse width modulation signal V PWM , then converts the alternating current voltage V AC into the input current I AC in accordance with the pulse width modulation signal V PWM . As shown in step S 12 , the input current I AC is converted into the output voltage V o by the AC/DC converter 24 of the power stage circuit 12 , and the input current I AC is also sampled via the sample resistor 22 as a correcting current I sen . As shown in step S 14 , the current compensating circuit 14 receives the correcting current I sen that is compared to a reference current signal I ref via the current compensating circuit 14 to generate the compensating current signal I EA . Specifically, the current error amplifier 26 receives and compares the correcting current I sen with the reference current signal I ref thus generates a comparing current. Then, the current compensator 28 receives and compensates the comparing current thus generates the compensating current signal I EA .
[0041] The voltage compensating circuit 16 receives the output voltage V o that is compared with a reference voltage V ref via the voltage compensating circuit 16 to generate the compensating voltage signal V EA . Specifically, the voltage divider 30 receives the output voltage V o to generate one feedback voltage. Then, the voltage error amplifier 32 receives and compares the feedback voltage with a reference voltage V ref to generate the comparing voltage. Finally, the voltage compensator 34 receives and compensates the comparing voltage thus generates the compensating voltage signal V EA .
[0042] An updated reference current signal I ref is obtained by multiplying the compensating current signal I EA by the compensating voltage signal V EA by the multiplication amplifier 18 . Specifically, the multiplier 36 receives the compensating current signal I EA and the compensating voltage signal V EA to generate the compensating feedback current by multiplying the compensating current signal I EA by the compensating voltage signal V EA , then the current gain regulator 38 receives the compensating feedback current that is multiplied by the current gain K m to generate the reference current signal I ref .
[0043] Finally, as shown in step S 16 , the pulse width modulation converter 20 receives the compensating current signal I EA and the compensating voltage signal V EA to generate the updated pulse width modulation signal V PWM that is transmitted into the power stage circuit 12 . Specifically, the ramp generator 40 receives the compensating voltage signal V EA to generate ramp signal V RAMP , then, conversion comparator 42 receives and compares the ramp signal V RAMP and compensating current signal I EA thus generates the updated pulse width modulation signal V PWM that is fed to the power stage circuit 12 , thus returning back to step S 10 . The whole process of steps S 10 to S 16 is repeated to achieve the phase synchronization for the alternating current voltage and the input current.
[0044] FIG. 4 shows the waveforms of the reference current signal I ref , compensating voltage signal V EA , feedback voltage V FB , alternating current voltage V AC , compensating current signal I EA and ramp signal V RAMP . FIG. 5 shows corresponding reference current signal I ref , compensating current signal I EA and compensating voltage signal V EA of FIG. 4 after amplifying.
[0045] In conversion process of the conversion comparator 42 , when the voltage value of the ramp signal V RAMP is higher than the corresponding voltage value of the compensating current signal I EA , the updated pulse width modulation signal V PWM is a high level voltage. Otherwise, when the voltage value of the ramp signal V RAMP is lower than the corresponding voltage value of the compensating current signal I EA , the updated pulse width modulation signal V PWM is a low level voltage, as shown in FIG. 6 .
[0046] FIG. 7 shows the waveforms of 220V alternating current voltage V AC and its input current I AC and FIG. 8 shows the waveforms of 110V alternating current voltage V AC and its input current I AC , which are achieved by the correction device of the present invention. As shown in these figures, the phases of the alternating current voltage V AC and its input current are the same, as such the purpose of power factor correction is achieved.
[0047] The present invention uses only one multiplication amplifier to receive compensating current signal and compensating voltage signal to generate the updated reference current signal that is provided to the current compensating circuit for correcting the power factor of the input signal.
[0048] The above is only one better embodiment of the invention, which is not used for limiting the scope of implementation of the invention. Therefore, equivalent changes and decorations caused by the shapes, configurations, characteristics and spirits in the scope of application for patent in the invention are all contained in the scope of the application for patent in the invention.
|
A power factor correction device comprises a power stage circuit converting input alternating current voltage into input current according to a pulse width modulation signal and outputs the input current to a load generating output voltage on the load, and sampling the input current outputting a correcting current; a current compensating circuit receiving and comparing the correcting current with a reference current signal generating a compensating current signal; a voltage compensating circuit receiving and comparing the output voltage with a reference voltage generating a compensating voltage signal; a multiplication amplifier receiving the compensating current signal and the compensating voltage signal generating an updated reference current signal by multiplying the compensating current signal with the compensating voltage signal; and a pulse width modulation converter receiving the compensating current signal and the compensating voltage signal generating the pulse width modulation signal to synchronize phase of alternating current voltage and input current.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional Application No. 61/289,696, filed on Dec. 23, 2009. The disclosure of the above application is incorporated herein by reference in its entirety.
FIELD
[0002] The present disclosure relates to inkjet printing and more particularly to an ultrasonic cleaning station for inkjet printing devices.
BACKGROUND
[0003] The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
[0004] Manufacturers have developed various techniques for fabricating microstructures that have small feature sizes. The microstructures may form one of more layers of an electronic circuit. Examples of these structures include light-emitting diode (LED) display devices, polymer LED (PLED) display devices, organic LED (OLED) devices, liquid crystal display (LCD) devices, and printed circuit boards. Many of these manufacturing techniques are relatively expensive to implement and require high production quantities to amortize the cost of the fabrication equipment.
[0005] One technique for forming microstructures on a substrate is screen printing. During screen printing, a fine mesh screen is positioned on the substrate. Fluid material is deposited through the screen and onto the substrate in a pattern defined by the screen. Screen printing therefore causes contact between the screen and the substrate. Contact also occurs between the screen and the fluid material, which contaminates both the substrate and the fluid material.
[0006] While screen printing is suitable for forming some microstructures, many manufacturing processes do not allow contamination of the substrate by the screen. Therefore, screen printing is not a viable option for the manufacture of certain microstructures. For example, polymer light-emitting diode (PLED) display devices may require a contamination-free manufacturing process.
[0007] Certain polymeric substances can be used to manufacture diodes that generate visible light of different wavelengths. Using these polymers, display devices having pixels with sub-components of red, green, and blue can be created. PLED fluid materials enable full-spectrum color displays and require very little power to emit a substantial amount of light. PLED displays can be used in various applications, including televisions, computer monitors, PDAs, other handheld computing devices, cellular phones, etc. PLED technology may also be used for manufacturing light-emitting panels that provide ambient lighting for office, storage, and living spaces. One obstacle to the widespread use of PLED display devices is the difficulty and expense of manufacturing PLED display devices.
[0008] Photolithography is another manufacturing technique that is used to manufacture microstructures on substrates. Photolithography may also be incompatible with PLED display devices. Manufacturing processes using photolithography generally involve the deposition of a photoresist material onto a substrate. The photoresist material is cured by exposure to light. A patterned mask is therefore used to selectively apply light to the photoresist material. Photoresist that is exposed to the light is cured and unexposed portions are not cured. The uncured portions can be removed from the substrate while the cured portions remain.
[0009] An underlying surface of the substrate is exposed through the removed photoresist layer. Another material is then deposited onto the substrate through the opened pattern on the photoresist layer, followed by the removal of the cured portion of the photoresist layer.
[0010] Photolithography has been used successfully to manufacture many microstructures, such as traces on circuit boards. However, photolithography contaminates the substrate and the material formed on the substrate. Photolithography may not be compatible with the manufacture of PLED displays because the photoresist contaminates the PLED polymers. In addition, photolithography involves multiple steps for applying and processing the photoresist material. The cost of the photolithography process can be prohibitive when relatively small quantities are to be fabricated. Further, expensive PLED material may be lost when it is deposited on cured photoresist that is later removed.
[0011] Spin coating has also been used to form microstructures. Spin coating involves rotating a substrate while depositing fluid material at the center of the substrate. The rotational motion of the substrate causes the fluid material to spread evenly across the surface of the substrate. Spin coating is also an expensive process because a majority of the fluid material does not remain on the substrate. In addition, the size of the substrate is limited by the spin coating process to less than approximately 12″, which makes spin coating unsuitable for larger devices such as PLED televisions.
SUMMARY
[0012] A microdeposition system includes a printhead carriage that includes N rows of nozzles and that moves along a first axis; a stage that holds a substrate and that moves the substrate along a second axis that is perpendicular to the first axis, and a maintenance station located at a position along the first axis that is past an edge of the substrate. N is an integer greater than one. The N rows of nozzles selectively deposit droplets of fluid manufacturing material onto the substrate.
[0013] In other features, the maintenance station includes N capping chambers arranged in two groups of N/2 capping chambers. The N capping chambers simultaneously immerse the N rows of nozzles in one of a solvent and a vapor rich environment of the solvent. The maintenance station also includes an ultrasonic cleaning station located between the two groups of N/2 capping chambers. The printhead carriage rotates between first and second orientations. Each of the N rows of nozzles is parallel to the first axis when the printhead carriage is in the first orientation. Each of the N rows of nozzles is parallel to the second axis when the printhead carriage is in the second orientation. The printhead carriage rotates to the second orientation for maintenance by the maintenance station.
[0014] In further features, the ultrasonic cleaning station includes a water tank holding deionized water; ultrasonic transducers mounted to an external bottom surface of the water tank that apply ultrasonic vibrations to the deionized water; and an inner trough that is partially submerged in the water tank. The inner trough is filled with the solvent, and selectively immerses one of the N rows of nozzles in the solvent. The water tank includes a temperature sensor that measures a temperature of the deionized water. The ultrasonic transducers are deactivated when the temperature of the deionized water is greater than a threshold.
[0015] In other features, the maintenance station includes a blotting station located past the N capping chambers along the first axis. The blotting station includes a feed roller that dispenses blotting material; a waste roller that winds up the blotting material; and a spray bar that moves perpendicular to the first axis and deposits N lines of the solvent on the blotting material.
[0016] A microdeposition system includes a printhead carriage that includes N rows of nozzles and that moves along a first axis; a stage that holds a substrate; and a maintenance station located at a position along the first axis that is past an edge of the substrate. The N rows of nozzles selectively deposit droplets of fluid manufacturing material onto the substrate. The maintenance station includes a capping station and an ultrasonic cleaning station located in a middle of the capping station. N is an integer greater than one.
[0017] In other features, the stage moves the substrate along a second axis that is perpendicular to the first axis. The printhead carriage rotates between first and second orientations. Each of the N rows of nozzles is parallel to the first axis when the printhead carriage is in the first orientation. Each of the N rows of nozzles is parallel to the second axis when the printhead carriage is in the second orientation. For maintenance by the maintenance station, the printhead carriage rotates to the second orientation. For depositing the droplets on the substrate, the printhead carriage rotates to a printing orientation that is adjustable between the first orientation and a predetermined orientation. The predetermined orientation is between the first orientation and the second orientation.
[0018] In further features, the capping station includes N capping chambers. The N capping chambers simultaneously immerse the N rows of nozzles in one of a fluid and a vapor rich environment of the fluid. The fluid includes at least one of a solvent and the fluid manufacturing material. The ultrasonic cleaning station receives one of the N rows of nozzles at a time. When the one of the N rows of nozzles is placed in the ultrasonic cleaning station, remaining rows of the N rows of nozzles are outside of the N capping chambers.
[0019] In other features, the printhead carriage moves down in a direction perpendicular to the substrate to place the one of the N rows of nozzles into the ultrasonic cleaning station. The printhead carriage moves down in the direction perpendicular to the substrate to immerse the N rows of nozzles in the N capping chambers. When the one of the N rows of nozzles is placed in the ultrasonic cleaning station, one of the remaining rows of the N rows of nozzles is located between the ultrasonic cleaning station and one of the N capping chambers, and others of the remaining rows of the N rows of nozzles are located outside of the capping station. The N capping chambers are arranged in two groups of N/2 capping chambers. The ultrasonic cleaning station is located between the two groups of N/2 capping chambers.
[0020] In further features, the ultrasonic cleaning station includes a water tank that holds water; ultrasonic transducers that apply ultrasonic vibrations to the water; and an inner trough that is filled with solvent and that receives at least one of the N rows of nozzles. The ultrasonic vibrations are transferred from the water to the solvent. The inner trough is partially submerged in the water tank. The ultrasonic transducers are mounted to an external bottom surface of the water tank. The ultrasonic cleaning station further includes a temperature sensor located in the water tank that measures a temperature of the water. The ultrasonic transducers are deactivated when the temperature of the water is greater than a threshold.
[0021] In other features, the maintenance station includes a blotting station that is located at a position along the first axis that is past the capping station. The blotting station moves up along an axis perpendicular to the substrate to engage the N rows of nozzles. The blotting station moves down along the axis perpendicular to the substrate to allow use of the ultrasonic cleaning station. The blotting station moves down along the axis perpendicular to the substrate to allow manual maintenance of the N rows of nozzles.
[0022] In further features, the blotting station includes a feed roller that dispenses blotting material; a waste roller that winds up the blotting material; and a spray bar that moves perpendicular to the first axis and deposits a line of solvent on the blotting material. The spray bar deposits N lines of the solvent including the line on the blotting material.
[0023] Further areas of applicability of the present disclosure will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] The present disclosure will become more fully understood from the detailed description and the accompanying drawings, wherein:
[0025] FIG. 1 is an isometric view of an example implementation of a microdeposition system according to the principles of the present disclosure;
[0026] FIG. 2 is a simplified top view of an example implementation of a microdeposition system according to the principles of the present disclosure;
[0027] FIG. 3 is an isometric view of an example pack of printhead modules according to the principles of the present disclosure;
[0028] FIGS. 4A-4C are partial side views of an example maintenance station showing relative positions of printhead modules according to the principles of the present disclosure;
[0029] FIG. 5 is an isometric view of an example maintenance station according to the principles of the present disclosure;
[0030] FIG. 6A is an isometric view of an example ultrasonic cleaning station according to the principles of the present disclosure;
[0031] FIG. 6B is an exploded isometric view of an example ultrasonic cleaning station according to the principles of the present disclosure; and
[0032] FIG. 7 is a functional block diagram of fluid control for an example ultrasonic cleaning station according to the principles of the present disclosure.
DETAILED DESCRIPTION
[0033] The following description is merely illustrative in nature and is in no way intended to limit the disclosure, its application, or uses. For purposes of clarity, the same reference numbers will be used in the drawings to identify similar elements. As used herein, the phrase at least one of A, B, and C should be construed to mean a logical (A or B or C), using a non-exclusive logical or. It should be understood that steps within a method may be executed in different order without altering the principles of the present disclosure.
[0034] The terms “fluid manufacturing material” and “fluid material,” as defined herein, are broadly construed to include any material that can assume a low viscosity form and that is suitable for being deposited, for example, from a microdeposition head onto a substrate for forming a microstructure. Fluid manufacturing materials may include, but are not limited to, light-emitting polymers (LEPs), which can be used to form polymer light-emitting diode display devices (PLEDs and PolyLEDs). Fluid manufacturing materials may also include plastics, metals, waxes, solders, solder pastes, biomedical products, acids, photoresists, solvents, adhesives, and epoxies. The term “fluid manufacturing material” is interchangeably referred to herein as “fluid material.”
[0035] The term “deposition,” as defined herein, generally refers to the process of depositing individual droplets of fluid materials on substrates. The terms “let,” “discharge,” “pattern,” and “deposit” are used interchangeably herein with specific reference to the deposition of the fluid material from a microdeposition head, for example. The terms “droplet” and “drop” are also used interchangeably.
[0036] The term “substrate,” as defined herein, is broadly construed to include any material having a surface that is suitable for receiving a fluid material during a manufacturing process such as microdeposition. Substrates include, but are not limited to, glass plate, pipettes, silicon wafers, ceramic tiles, FR-4 and other printed circuit board materials, rigid and flexible plastic, and metal sheets and rolls. In certain embodiments, a deposited fluid material itself may form a substrate, as the fluid material itself also includes surfaces suitable for receiving a fluid material during manufacturing, such as, for example, when forming three-dimensional microstructures.
[0037] The term “microstructures,” as defined herein, generally refers to structures formed with a high degree of precision, and that are sized to fit on a substrate. Because the sizes of different substrates may vary, the term “microstructures” should not be construed to be limited to any particular size and can be used interchangeably with the term “structure.” Microstructures may include a single droplet of a fluid material, any combination of droplets, or any structure formed by depositing the droplet(s) on a substrate, such as a two-dimensional layer, a three-dimensional architecture, and any other desired structure.
[0038] The microdeposition systems referenced herein perform processes by depositing fluid materials onto substrates according to user-defined computer-executable instructions. The term “computer-executable instructions,” which is also referred to herein as “program modules” or “modules,” generally includes routines, programs, objects, components, data structures, or the like that implement particular abstract data types or perform particular tasks such as, but not limited to, executing computer numerical controls for implementing microdeposition processes.
[0039] Program modules may be stored on any non-transitory, tangible computer-readable media, including, but not limited to RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium capable of storing instructions or data structures and capable of being accessed by a general purpose or special purpose computer.
[0040] Referring now to FIG. 1 , a microdeposition system 100 includes a printhead carriage 104 that slides along beams 108 . For example only, the beams 108 may be constructed from granite. The direction of travel of the printhead carriage 104 may be called the x axis. The printhead carriage 104 includes one or more rows of nozzles that deposit a fluid manufacturing material on a substrate 112 . For example only, the substrate 112 may be a sheet of glass and may be a component of a PLED video monitor or television.
[0041] The substrate 112 may be secured by a chuck, which may hold the substrate 112 using a vacuum. The substrate 112 may translate back and forth along the y axis, which is perpendicular to the x axis. For example only, the printhead carriage 104 may align the rows of nozzles to be parallel to the x axis. As the substrate 112 moves along the y axis, the rows of nozzles selectively deposit fluid manufacturing material onto the substrate 112 . The rows of nozzles may be unable to cover the entire substrate 112 in one pass. The printhead carriage 104 may therefore translate to another position along the x axis. The substrate 112 will then move along the y axis again to print the next pass.
[0042] Alternatively, the printhead carriage 104 may print while moving along the x axis. The substrate 112 would then translate to a new position along the y axis after each pass of the printhead carriage 104 is completed. The nozzles in the printhead carriage 104 may be periodically maintained to ensure uniform dispensing of droplets. In various implementations, nozzle maintenance may be performed when the substrate 112 is being loaded into the microdeposition system 100 and/or when the substrate 112 is being unloaded from the microdeposition system 100 .
[0043] A nozzle maintenance station 116 may be located further along the x axis outside of the area where printing takes place. If instead the nozzle maintenance station 116 were positioned at a location where printing was performed, such as at location 120 , it may be necessary to move the nozzle maintenance station 116 below the plane of the substrate 112 in order to avoid interfering with printing.
[0044] There may be packaging constraints regarding how much room is available below the plane of the substrate. For example, portions of the chuck that holds the substrate 112 and support structures for the microdeposition system 100 may be in the way. In addition, when the nozzle maintenance station 116 would be raised to perform nozzle maintenance, loading of a new substrate may be blocked. For these reasons, the nozzle maintenance station may be located at the end of the x axis movement of the printhead carriage 104 , past the area where printing takes place.
[0045] The x axis structures, including the beams 108 , may need to be extended to allow for this additional x axis movement of the nozzle maintenance station 116 beyond the length needed for printing. As the length of the x axis structures increases, the overall cost, size, and weight of the microdeposition system 100 increases. The present disclosure describes techniques for reducing additional x axis travel.
[0046] Referring now to FIG. 2 , a simplified top view of the microdeposition system 100 is shown. The nozzle maintenance station 116 includes a capping station 204 and a blotting station 208 . The capping station 204 may include troughs where the nozzles can be soaked to prevent the nozzles from drying out. The nozzles may be immersed in fluid or may be placed in a vapor rich environment above the fluid.
[0047] The capping station 204 may also seal the nozzles to prevent air movement from drying the nozzles. In addition, manufacturing fluids and/or solvent may be jetted from the nozzles into the capping station. This may be performed to clean the nozzles and/or when changing deposition fluids. In addition, droplet analysis may be performed while jetting droplets into the capping station 204 .
[0048] For example, measurements regarding the speed, trajectory, size, and shape of droplets may be made. Deviations from desired values may be compensated for electronically and/or may result in cleaning procedures and/or other remedial measures. For example only, nozzle firing timing may be adjusted to compensate for deviations in droplet trajectory or speed. For example only, a cleaning procedure may be performed on the nozzles by the blotting station 208 .
[0049] One or more nozzles may contact a blotting surface on the blotting station 208 . The blotting station 208 may wipe the nozzles by moving the blotting surface while the nozzles are in contact with the blotting surface. For example only, a roll of blotting material may be dispensed from a feed roller and wound up by a waste roller. Solvent may be deposited on the blotting material to perform a wet wipe of the nozzles.
[0050] Certain manufacturing fluids may contaminate the nozzles to an extent that the contamination is not removed by the capping station 204 and the blotting station 208 . In various implementations, a fluid manufacturing material may be used that is not a dispersion but a mixture of discrete particles and solvent. For example, to separate pixel regions in liquid crystal display (LCD) manufacturing, spacer particles may be mixed with solvent. When this mixture is deposited on a substrate, the solvent may be removed, such as through evaporation, leaving the spacer particles on the substrate.
[0051] For example only, spacer particles may include acrylic spheres with bonding agent applied, where the acrylic spheres have diameters between three and five microns. The spacer particles may tend to settle out of the solvent without continual ink circulation, sonification, and filtration. As such, the spacer particles may build up in low fluid flow regions or regions where natural eddy currents are present. Another cleaning station may therefore be implemented. For example, ultrasonic cleaning may release buildup of various materials in the nozzles. However, adding an ultrasonic cleaner after the blotting station 208 would require further x axis movement of the printhead carriage 104 .
[0052] Referring now to FIG. 3 , a pack 304 may include multiple printhead modules 308 . Each printhead module 308 may include multiple nozzles. For example only, the pack 304 may include six printhead modules 308 . Each of the printhead modules 308 may include 128 nozzles. An example implementation of the pack 304 would therefore have 6*128 (768) nozzles that are substantially colinear. Fluid for each of the printhead modules 308 may be received from a multiple-port fluid connector 312 . Nozzle firing waveforms may be received via ribbon cable headers 316 , which may be located at both ends of the pack 304 .
[0053] Referring back to FIG. 2 , an example implementation of the printhead carriage 104 may include four of the packs 304 . Each of the packs is shown with six printhead modules, although more or fewer may be present. The packs 304 may be able to rotate 90 degrees, so that the rows of nozzles are perpendicular to the y axis (the direction of substrate travel) for printing and parallel to the y axis for maintenance. In addition, intermediate angles may be used to change the pitch of the nozzles with respect to the moving substrate. FIG. 2 shows the rows of nozzles being parallel to the y axis for maintenance.
[0054] When depositing solvent-suspended particles, such as spacer particles, the nozzles may be cleaned after each substrate is printed. In order to minimize production time, ultrasonic cleaning of the nozzles may be performed during the time it takes for one substrate to be unloaded and another to be loaded.
[0055] In various implementations, there may be enough time to perform four ultrasonic cleaning operations. Each of the packs may therefore be cleaned sequentially. This reduces the size of the ultrasonic cleaning assembly by approximately three-quarters. However, in order to create enough clearance for the other three packs while one pack is being cleaned, the ultrasonic cleaning station may still need to be positioned further out along the x axis. As shown in FIGS. 4A-4C , appropriately designing the spacing of the packs may allow for an ultrasonic cleaning station 212 to be located inside of the capping station 204 .
[0056] Referring now to FIG. 4A , a simplified side view of the capping station 204 and the ultrasonic cleaning station 212 is shown. In an implementation where four packs 304 are present, the capping station 204 may include four capping chambers 404 . Each of the packs 304 lines up with each of the capping chambers 404 . The packs 304 may be lowered into the capping chambers 404 and/or the capping chambers 404 may be raised.
[0057] The ultrasonic cleaning station 212 is located between the first two of the capping chambers 404 and the second two of the capping chambers 404 . In FIG. 4B , the printhead carriage has moved to position one of the packs 304 over the ultrasonic cleaning station 212 . In order to submerge the pack 304 into the ultrasonic cleaning station, the packs may be lowered and/or the ultrasonic cleaning station 212 may be raised.
[0058] In various implementations, the printhead carriage 104 may have the ability to adjust the packs 304 up or down (along the z axis) to allow for varying thicknesses of substrate. The packs 304 can therefore be lowered into the ultrasonic cleaning station 212 . Once lowered, one of the packs 304 will be located in the void between the ultrasonic cleaning station 212 and the second pair of capping chambers 404 . The other two packs 304 are located past the capping station 204 .
[0059] Similarly, when submerging a second one of the packs 304 , the first one of the packs 304 will occupy the void between the first pair of the capping chambers 404 and the ultrasonic cleaning station 212 , as shown in FIG. 4C . Positioning of the remaining two packs 304 in the ultrasonic cleaning station 212 may be mirror images of FIGS. 4B-4C .
[0060] Referring now to FIG. 5 , the capping chambers 404 are seen in an isometric view, with the ultrasonic cleaning station 212 located between the two sets of capping chambers 404 . Because the capping station 204 surrounds the ultrasonic cleaning station 212 , a vacuum that is applied by the capping station 204 to prevent evaporating solvent from escaping may also control evaporating solvent from the ultrasonic cleaning station 212 . Further, the capping station 204 may provide overflow trays that capture overflow from the ultrasonic cleaning station 212 .
[0061] The blotting station 208 is shown in a lowered position. This lowered position may allow for manual inspection and maintenance of nozzles and nozzle assemblies. Additionally or alternatively, as one of the packs 304 is lowered into the ultrasonic cleaning station 212 , the lowered position may provide clearance for remaining ones of the packs 304 . In order to perform a blotting operation, the blotting station 208 may be raised.
[0062] Blotting material 504 is drawn across the top of the blotting station. For example only, a feed roller 508 may dispense blotting material 504 and a waste roller 512 may wind up the blotting material 504 . The blotting station 208 may include a spray bar 516 that sprays solvent onto the blotting material 504 . In various implementations, the spray bar 516 may be mounted to a carriage 520 that rides along a rail 524 disposed parallel to the y axis. The spray bar 516 may spray solvent in four stripes, one for each of the packs.
[0063] Referring now to FIG. 6A , an example of an ultrasonic cleaning station 212 includes a water tank 604 coupled to ultrasonic transducers 608 . The ultrasonic transducers 608 introduce ultrasonic vibration into the water within the water tank 604 . An inner solvent trough 612 contains solvent. The solvent trough 612 is partially submerged in the water of the water tank 604 . Ultrasonic vibration of the water is transferred to the solvent within the solvent trough 612 , into which nozzles of a pack are inserted. The ultrasonic vibration and the chemical action of the solvent remove contaminants from the nozzles.
[0064] The solvent trough 612 may be filled via a solvent inlet 616 , which may pass through the water tank 604 . The solvent trough 612 may be filled until solvent overflows into an overflow trough 620 . The overflow trough 620 surrounds the solvent trough 612 , and a solvent waste pipe 624 is present on each end of the overflow trough 620 .
[0065] A fluid sensor 628 may be located on each of the waste pipes 624 . The fluid sensor 628 indicates when fluid is present in the waste pipe 624 . Once fluid is present in the waste pipe 624 , the solvent trough 612 is determined to be full and the supply of solvent is halted.
[0066] The water tank 604 may be filled using a water fill inlet 640 . In various implementations, deionized water may be used in the water tank 604 . A loop 644 may be formed to detect the level of water present in the water tank 604 . The loop 644 may be connected to the water tank via a coupling 648 . A fluid level sensor 652 may be located near the top of the loop 644 . An outlet coupling 656 may be connected to the loop 644 and may allow overflowing water to escape to an overflow tank. In addition, the outlet coupling 656 may allow trapped air to escape from the loop 644 to allow for accurate water level readings and to prevent backpressure when filling the water tank 604 .
[0067] Referring now to FIG. 6B , an exploded view of the ultrasonic cleaning station 212 of FIG. 6A includes a support bracket 670 . The support bracket 670 may attach to the water tank 604 via a gasket 674 . In addition, a gasket 678 located between the solvent trough 612 and the water tank 604 may prevent water leakage and cross-contamination between the solvent and the water.
[0068] Referring now to FIG. 7 , a fluid control module 704 applies pressure, which may be positive or negative, to a solvent reservoir 708 . The solvent reservoir 708 may include an overfill sensor 710 , a full sensor 712 , and a refill sensor 714 . When the refill sensor 714 does not detect fluid presence, filling of the solvent reservoir 708 begins. Filling may continue until the full sensor 712 detects fluid presence.
[0069] When the overfill sensor 710 detects fluid presence, solvent may need to be drained from the solvent reservoir 708 . For example only, the solvent reservoir 708 may output solvent to the solvent trough 612 , which may then overflow and be removed as waste. The solvent reservoir 708 may stop outputting the solvent when the full sensor 712 no longer detects fluid presence.
[0070] Applying pressure to the solvent reservoir 708 may push solvent through a filter 720 and then through a check valve 724 and into the solvent trough 612 . Applying a negative pressure draws solvent from the solvent trough 612 to a second check valve 728 and then through a second filter 732 before the solvent returns to the solvent reservoir 708 . In various implementations, solvent may be removed from the solvent trough 612 when the ultrasonic cleaning station 212 is not in use. This may minimize evaporation of solvent and also allows for the solvent to be filtered by the filters 720 and 732 .
[0071] Solvent overflowing into the overflow trough 620 passes by either of the first and second fluid sensors 628 before arriving at a solvent waste valve 740 . The solvent waste valve 740 may remain closed until enough solvent backs up to trip one of the fluid sensors 628 . The solvent waste valve 740 may then be opened, allowing the solvent to go to a waste collection location. Alternatively, solvent from the solvent waste valve 740 may be filtered and replaced into the solvent reservoir 708 .
[0072] Water may be added to the water tank 604 via a check valve 750 . A stopcock 752 may allow water to be drained from the water tank 604 when the check valve 750 is bypassed. The level of water within the water tank 604 may be measured by a water level sensor 760 attached to an indicator tube 764 .
[0073] An overflow tube 768 may be located within the water tank 604 to allow water to overflow to a water overflow reservoir 772 and also to allow air to escape from the water tank 604 . In various implementations, the overflow tube 768 and the indicator tube 764 may be implemented in a single structure, such as the loop 644 of FIG. 6A . An ultrasound driver 780 may be driven by ultrasound amplifiers 784 , which are selectively energized by a relay 788 . A temperature sensor 792 , such as a thermistor, may check to make sure that the water temperature does not increase above a predetermined threshold. Ultrasonic energization may be stopped if the water temperature crosses this threshold.
[0074] The broad teachings of the disclosure can be implemented in a variety of forms. Therefore, while this disclosure includes particular examples, the true scope of the disclosure should not be so limited since other modifications will become apparent to the skilled practitioner upon a study of the drawings, the specification, and the following claims.
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A microdeposition system includes a printhead carriage that includes N rows of nozzles and that moves along a first axis; a stage that holds a substrate; and a maintenance station located at a position along the first axis that is past an edge of the substrate. The N rows of nozzles selectively deposit droplets of fluid manufacturing material onto the substrate. The maintenance station includes a capping station and an ultrasonic cleaning station located in a middle of the capping station. N is an integer greater than one.
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BACKGROUND OF THE INVENTION
(1) Field of the Invention
The present invention relates to methods used for fabrication of high density, semiconductor memory cells, and more specifically to a process used to create a stacked capacitor, DRAM structure, with increased capacitance resulting from an increased surface capacitor surface area.
(2) Description of the Prior Art
The objectives of the semiconductor industry are to continually improve device performance, while still attempting to decrease the manufacturing cost of specific semiconductor chips. These objectives have been in part realizedby the ability of the semiconductor industry to produce chaps with sub-micron features, or mtcro-miniaturization. Smaller features allow the reduction in performance degrading capacitances and resistances to be realized. In addition smaller features result in a smaller chip, however possessing the same level of integration obtained for semiconductor chips fabricated with larger features. This allows a greater number of the denser, smaller chips to be obtained from a specific size starting substrate, thus resulting in a lower manufacturing cost for an individual chip.
The use of smaller features, when used for the fabrication of dynamic random access memory, (DRAM), devices, in which the capacitor of the DRAM device is a stacked capacitor, (STC), structure, presents difficulties when attempting to increase STC capacitance. A DRAM cell is usually comprised of the STC structure, overlying a transfer gate transistor, and connected to the source of the transfer gate transistor. However the decreasing size of the transfer gate transistor, limits the dimensions of the STC structure. To increase the capacitance of the STC structure, comprised of two electrodes, separated by a dielectric layer, either the thickness of the dielectric layer has to be decreased, or the area of the capacitor has to be increased. The reduction in dielectric thickness is limited by increasing reliability and yield risks, encountered with ultra thin dielectric layers. In addition the area of the STC structure is limited by the area of the underlying transfer gate transistor dimensions. The advancement of the DRAM technology to densities of 64 million cells per chip, or greater, has resulted in a specific cell in which a smaller transfer gate transistor is being used, and thus limiting the amount of area the overlying STC structure can occupy, without interfering with neighboring cells.
Solutions to the shrinking design area, assigned to STC structures, have been addressed via novel semiconductor fabrication processes which result in an increase in surface area for only the lower, or storage electrode, of the STC structure, while maintaining the area original design area of the STC structure. One method for achieving this objective been accomplished by creating lower electrodes with pillars, or protruding shapes of polysilicon, thus resulting in a greater electrode surface area then would have been achieved with conventional flat surfaces. Kim, in U.S. Pat. No. 5,447,882, describes such an STC structure, comprised of a lower electrode, formed by creating protruding polysilicon features, via patterning of a polysilicon layer. This invention will describe a process in which a lower electrode of an STC structure is fabricated using multiple polysilicon mesas, each featuring protruding polysilicon spacers, thus offering greater increases in lower electrode surface area, of an STC structure, then for structures described in prior art.
SUMMARY OF THE INVENTION
It is an object of this invention to create a DRAM device, with an STC structure, in which the surface area of the lower electrode, of the STC structure is increased, without increasing the width of the STC structure.
It is another object of this invention to form the lower electrode of the STC structure by initially defining the capacitor area in a composite layer of insulator layer, overlying a polysilicon layer.
It is yet another object of this invention to create a lower electrode featuring a mesa pattern, defined by etching a pattern in the insulator layer, and continuing to etch the mesa pattern into only a portion of the underlying polysilicon layer, leaving an unetched portion of polysilicon, underlying the multiple mesas.
It is still another object of this invention to form polysilicon spacers on the sidewalls of the mesas, followed by removal of the meas insulator layer, resulting in a lower electrode of multiple mesas, comprised of protruding polysilicon features.
In accordance with the present invention a method for fabricating increased capacitance DRAM devices, via use of an STC structure, comprised of a lower electrode with increased surface area, has been developed. A transfer gate transistor comprised of: a thin gate insulator; a polysilicon gate structure; lightly doped source and drain regions; insulator spacers on the sidewalls of the polysilicon gate structure; and heavily doped source and drain regions; is formed on a semiconductor substrate. An insulator layer is deposited and an opening in the insulator layer is made to expose the source region of the transfer gate transistor. A contact plug, of conductive material, is formed in the opening to the source region, followedby the deposition of a polysilicon layer, and an overlying insulator layer. The insulator layer and underlying polysilicon layer are patterned to form the desired width of the lower electrode of the STC structure. A pattern of multiple mesas are then etched in the insulator layer, and partially into the polysilicon layer, resulting in multiple mesas of insulator--polysilicon, on a continuous, underlying polysilicon layer. Another deposition of polysilicon is performed, followed by an anisotropic, reactive ion etching procedure, producing polysilicon spacers on the sidewalls of the insulator-polysilicon mesas. The insulator, of the insulator-polysilicon mesas, is then removed, resulting in a polysilicon lower electrode, with multiple mesas featuring protruding polysilicon spacers, on the sidewalls of the mesas. A capacitor dielectric layer is next formed on the polysilicon lower electrode, followed by the creation of an upper polysilicon electrode, completing the processing of the STC structure.
BRIEF DESCRIPTION OF THE DRAWINGS
The object and other advantages of this invention are best explained in the preferred embodiment with reference to the attached drawings that include:
FIGS. 1-7, which schematically shows, in crosssectional style, the key fabrication stages used in the creation of a DRAM device, with a STC structure, with an increased surface area, resulting from a lower electrode comprised of polysilicon spacers on the sides of polysilicon mesas.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The method of forming a DRAM device, with increased capacitance, resulting from the use of a STC structure that features a lower electrode, comprised of polysilicon spacers, on the sides of polysilicon mesas, will now be described. The transfer gate transistor, used for this DRAM device, in this invention, will be an N channel device. However the STC structure, with the increased surface area described in this invention, can also be applied to P channel, transfer gate transistor.
Referring to FIG. 1, a P type, semiconductor substrate, 1, with a <100>, single crystalline orientation, is used. Field oxide, (FOX), regions, 2, are used for purposes of isolation. Briefly the FOX regions, 2, are formed via thermal oxidation, in an oxygen-steam ambient, at a temperature between about 850° to 1050° C., to a thickness between about 3000 to 5000 Angstroms. A patterned oxidation resistant mask of silicon nitride-silicon oxide is used to prevent FOX regions, 2, from growing on areas of substrate, 1, to be used for subsequent device regions. After the growth of the FOX regions, 2, the oxidation resistant mask is removed via use of a hot phosphoric acid solution for the overlying, silicon nitride layer, and a buffered hydrofluoric acid solution for the underlying silicon oxide layer. After a series of wet cleans, a gate insulator layer, 3, of silicon oxide is thermally grown in an oxygen-steam ambient, at a temperature between about 850° to 1050° C., to a thickness between about 50 to 200 Angstroms. A first polysilicon layer is next deposited using low pressure chemical vapor deposition, (LPCVD), procedures, at a temperature between about 500° to 700° C., to a thickness between about 1500 to 4000 Angstroms. The polysilicon can either be grown intrinsically and doped via ion implantation of arsenic or phosphorous, at an energy between about 30 to 80 KeV, at a dose between about 1E13 to 1E16 atoms/cm 2 , or grown using in situ doping procedures, via the incorporation of either arsine or phosphine to the silane ambient. Conventional photolithographic and reactive ion etching, (RIE), procedures, using Cl 2 as an etchant, are used to pattern the polysilicon layer, creating polysilicon gate structure, 4, shown schematically in FIG. 1. Photoresist removal is accomplished via plasma oxygen ashing and careful wet cleans.
A lightly doped source and drain region, 5, is next formed via ion implantation of phosphorous, at an energy between about 20 to 50 KeV, at a dose between about 1E13 to 1E14 atoms/cm 2 . A first insulator layer of silicon oxide is then deposited using either LPCVD or PECVD procedures, at a temperature between about 400° to 700° C., to a thickness between about 1500 to 4000 Angstroms, followed by an anisotropic RIE procedure, using CHF 3 as an etchant, creating insulator spacer, 6, on the sidewalls of polysilicon gate structure, 4. A heavily doped source and drain region, 7, is then formed via ion implantation of arsenic, at an energy between about 30 to 80 KeV, at a dose between about 1E15 to 1E16 atoms/cm 2 . The result of these procedures are schematically shown in FIG. 1.
A second insulator layer of silicon oxide, 8, is next deposited using LPCVD or PECVD procedures, at a temperature between about 400° to 700° C., to a thickness between about 4000 to 6000 Angstroms. Conventional photolithographic and RIE procedures, using CHF 3 as an etchant, are used to open contact hole, 9, in silicon oxide layer, 9, exposing the top surface of heavily doped source and drain region, 7. Photoresist removal is performed via use of plasma oxygen ashing and careful wet cleans. A conductive contact plug, 10, schematically shown in FIG. 2, is next formed. Several options of forming contact plug, 10, are available. The preferred option is the selective LPCVD deposition of tungsten, performed at a temperature between about 300° to 500° C., to a thickness equal to the thickness of silicon oxide layer, 8, between about 4000 to 6000 Angstroms, using WF 6 and silane as reactants. This deposition results in a tungsten contact plug, 10, in contact hole, 9, formed by selectively depositing only on exposed silicon surfaces, therefore eliminating the need for etchback or planarization. A second option is to deposit tungsten via r.f. sputtering, or non-selective LPCVD procedures, to a thickness great enough to allow complete filling of contact hole 9, and followed by an planarization procedure, either RIE or chemical mechanical polishing, used to remove unwanted tungsten from areas outside the contact hole to form tungsten contact plug, 10. A third option is to deposit polysilicon via LPCVD procedures, to a thickness again great enough to completely fill contact hole, 9, and followed again by planarization procedures, either RIE or chemical mechanical polishing, to result in a polysilicon contact plug, 10, only in contact hole, 9.
A second layer of polysilicon, 11a, is next deposited, via LPCVD procedures, at a temperature between about 500° to 700° C., to a thickness between about 3000 to 6000 Angstroms. Polysilicon layer, 11a, can be deposited intrinsically and doped via ion implantation of either phosphorous or arsenic, at an energy between about 25 to 75 KeV, at a dose between about 1E13 to 1E15 atoms/cm 2 , or polysilicon layer, 11a, can be deposited using in situ doping procedures, via the addition of either phosphine or arsine, to a silane ambient. A third insulator layer of silicon oxide, 12a, is next deposited using either LPCVD or plasma enhanced chemical vapor deposition, (PECVD), procedures, at a temperature between about 650° to 750° C., to a thickness between about 3000 to 6000 Angstroms. Insulator layer, 12a, can also be silicon nitride, again obtained via either LPCVD or PECVD procedures. Insulator layer, 12a, can also be a BPSG or PSG layer, obtained via addition of either PH 3 and B 2 H 6 , or just PH 3 , to a TEOS, (tetraethylorthosilicate), ambient. FIG. 3, shows the result of a first photolithographic and RIE procedure, using CHF 2 as an etchant for silicon oxide layer, 12a, and Cl 2 as an etchant for polysilicon layer, 11a. This procedure defines the width of the lower electrode, of a subsequent STC structure. Photoresist removal is accomplished via plasma oxygen ashing and careful wet cleans.
A second photolithographic and RIE procedure is next used to create a pattern of multiple, silicon oxide, 12b,--polysilicon, 11b, mesas, schematically illustrated in FIG. 4. First, photoresist shapes, 13, are used as a mask to transfer photoresist shape, 13, to the underlying silicon oxide layer, 12a, of the lower electrode, via RIE procedures using CHF 3 as an etchant. Next polysilicon layer, 11a, of the lower electrode shape is patterned, via RIE etching, using Cl 2 as an etchant, and again using photoresist shape, 13, as a mask. However in this procedure polysilicon layer, 11a, is only etched to remove between about 1500 to 3000 Angstroms, therefore leaving between about 1500 to 3000 Angstroms of polysilicon layer, 11a, unetched, and maintaining the continuity of polysilicon layer, across the width of the lower electrode, and underlying the multiple, silicon oxide, 12b, polysilicon, 11b, mesas. Photoresist shapes, 13, are then removed via plasma ashing and careful wet cleans.
A third layer of polysilicon is next deposited, using LPCVD procedures, at a temperature between about 500° to 700° C., to a thickness between about 500 to 2000 Angstroms. This polysilicon layer is grown using in situ doping procedures, by the addition of phosphine to the silane ambient. An anisotropic RIE procedure, using Cl 2 as an etchant is next employed to create polysilicon spacers, 14, on the sidewalls of the multiple, silicon oxide, 12b polysilicon, 11b, mesas. This is shown schematically in FIG. 5. The height of polysilicon spacers, 14, is the sum of the thickness of silicon oxide mesa, 12b, and the amount of polysilicon layer, 11a, removed during the formation of the multiple, silicon oxide, 12b,--polysilicon, 11b, mesas. FIG. 6. schematically shows the lower electrode structure after selective removal of silicon oxide layer, 12b, using a dilute, or buffered, hydrofluoric acid solution. The lower electrode, or storage node electrode, is comprised of polysilicon mesas, 11b, and protruding polysilicon spacers, 14.
The polysilicon mesa, polysilicon spacer, lower electrode structure, can be used for high density, DRAM designs, such as 64 Mb densities or greater. For high density designs, less available space is given for the STC structure, and therefore less mesas can be used. However the desired capacitances, or surface area, can be still be maintained by increasing the height of the polysilicon spacer. This can be accomplished via the use of mesas with either a thicker silicon oxide layer, a thicker polysilicon layer, or a deeper etching of the polysilicon, used for mesa creation.
FIG. 7, schematically shows the completion of the STC structure. First a dielectric layer, 15, is formed, overlying the polysilicon mesa, lower electrode, 11b, with protruding polysilicon spacers, 14. Dielectric layer, 15, can be an insulator layer possessing a high dielectric constant, such as Ta 2 O 5 , obtained via r.f sputtering techniques, at a thickness between about 10 to 100 Angstroms. Dielectric layer, 15, can also be ONO, (Oxidized--silicon Nitride--silicon Oxide). The ONO layer is formed by initially growing a silicon dioxide layer, between about 10 to 50 Angstroms, followed by the deposition of a silicon nitride layer, between about 10 to 20 Angstroms. Subsequent thermal oxidation of the silicon nitride layer results in the formation of a silicon oxynitride layer on silicon oxide, at a silicon oxide equivalent thickness of between about 40 to 80 Angstroms. Finally another layer of polysilicon is deposited, via LPCVD procedures, at a temperature between about 500° to 700° C., to a thickness between about 1000 to 3000 Angstroms. Doping of this polysilicon layer is accomplished via the in situ deposition procedure, again via the addition of phosphine, to a silane ambient. Photolithographic and RIE procedures, using Cl 2 as an etchant, are next employed to create polysilicon upper electrode, or plate electrode, 16, shown schematically in FIG. 7. Photoresist is again removed via plasma oxygen ashing and careful wet cleans.
While this invention has been particularly shown and described with reference to the preferred embodiments thereof, it will be understoodby those skilled in the art that various changes in form and details may be made without departing from the spirit and scope of this invention.
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A method of creating an STC structure, used for high density, DRAM designs, has been developed. The process consists of creating a lower, or storage node electrode, for the STC structure, consisting of multiple, polysilicon mesa structures, as well as polysilicon spacers, on the sides of the polysilicon mesas, with the polysilicon spacers protruding above the top surface of the polysilicon mesas. This is accomplished by initially creating a composite mesa structure, of an insulator layer, on a partially etched polysilicon layer. After creation of the polysilicon spacer, on the sides of the composite, mesa structure, the insulator is selectively removed, resulting in polysilicon mesas, with protruding polysilicon spacers. This storage node configuration results in an significant increase of surface area, when compared to storage nodes fabricated with flat topographies.
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FIELD OF THE INVENTION
[0001] The invention relates to a tensioner, and more particularly, a tensioner having a first damping member and a second damping member cooperatively connected to allow a relative axial movement and a compressive member disposed therebetween urging apart the first damping member and the second damping member.
BACKGROUND OF THE INVENTION
[0002] The two most common methods synchronously driving rotating members such as cam shafts and balance shafts from a crankshaft are timing chains and belts. Timing chains require engine oil to operate. In comparison most timing belt applications require that no oil be present in the belt drive as the presence of oil can damage the belt and inhibit its intended purpose. Recent improvements in belts no long require that a belt be isolated from the engine oil environment.
[0003] The recent improvement of belts to operate in oil, however poses other problems that need to be solved. One specific problem is properly tensioning the belt drive to keep the camshaft synchronized with the crankshaft. Should the camshaft or other synchronized driven crankshaft component loose synchronization with the crankshaft catastrophic engine damage can result.
[0004] To transmit power through the belt from the rotating crankshaft one side of the belt is pulled around the crankshaft and is commonly referred to as the belt tight side by those skilled in the art. Conversely the other side is referred to as the belt slack side, since the belt is being “pushed” away from the crankshaft. It is important to provide tensioning to the slack side of the belt to prevent the belt from becoming unduly slack and thus causing a loss of synchronization between the crankshaft and the components rotated by the crankshaft. This loss of synchronization is commonly referred to as “tooth jump” or “ratcheting” by those skilled in the art.
[0005] Compounding the problem of eliminating belt slack to prevent tooth jump or ratcheting is excessive tensioner arm motion or vibration induced by the engine's angular vibration. Excessive arm motion could not only lead to a tooth jump or ratcheting condition, but can also reduce the useful life of the tensioner and the belt as well. To minimize the amount of arm vibration friction damping is commonly used to prevent the tensioner from moving away from the belt.
[0006] The presence of oil makes friction damping difficult to achieve. Application of a lubricant to two rubbing surfaces will allow relative motion between the two surfaces to occur more easily.
[0007] Representative of the art is U.S. Pat. No. 7,951,030 which discloses a tensioner comprising a base, an arm pivotally engaged with the base, a pulley journalled to the arm, a torsion spring engaged between the arm and the base, the base comprising a cantilever leaf spring, a first friction disk operationally disposed between the cantilever leaf spring and the arm, the cantilever leaf spring biasing the first friction disk into frictional contact with the arm, the first friction disk rotationally fixed with respect to the base, a second friction disk rotationally fixed with respect to the base, a separator member disposed between the first friction disk and the second friction disk, the first friction disk and the second friction disk each having a wet coefficient of friction of approximately 0.12, and the separator member rotationally fixed with respect to the arm.
[0008] What is needed is a tensioner having a first damping member and a second damping member cooperatively connected to allow a relative axial movement and a compressive member disposed therebetween urging apart the first damping member and the second damping member. The present invention meets this need.
SUMMARY OF THE INVENTION
[0009] The primary aspect of the invention is to provide a tensioner having a first damping member and a second damping member cooperatively connected to allow a relative axial movement and a compressive member disposed therebetween urging apart the first damping member and the second damping member.
[0010] Other aspects of the invention will be pointed out or made obvious by the following description of the invention and the accompanying drawings.
[0011] The invention comprises a tensioner comprising a base, a shaft connected to the base, an eccentric adjuster coaxially engaged with the shaft, an arm pivotally engaged with the shaft, a pulley journalled to the arm, a torsion spring engaged between the arm and the base, the arm comprising a first receiving portion and a second receiving portion disposed axially opposite from the first receiving portion, a first damping member disposed between the arm and the base, the first damping member frictionally engaged with the base and engaged with first receiving portion, a second damping member disposed between the arm and the eccentric adjuster having a member engaged with the second receiving portion, and a biasing member disposed between the first damping member and the arm for applying a normal force to the first damping member and to the second damping member.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The accompanying drawings, which are incorporated in and form a part of the specification, illustrate preferred embodiments of the present invention, and together with a description, serve to explain the principles of the invention.
[0013] FIG. 1 is a cross-sectional view of the tensioner.
[0014] FIG. 2 is an exploded view of the tensioner.
[0015] FIG. 2 b is a side view of the wave spring.
[0016] FIG. 3 is an exploded view of the tensioner.
[0017] FIG. 4 is a cross-sectional view of an alternate embodiment.
[0018] FIG. 5 is an exploded view of the alternate embodiment in FIG. 4 .
[0019] FIG. 6 is a chart illustrating the spring rate (k) as a function of spring height.
[0020] FIG. 7 is a detail of the retainer and adjuster.
[0021] FIG. 8 is a detail of the retainer on the adjuster.
[0022] FIG. 9 is a detail of the assembled shaft and adjuster.
[0023] FIG. 10 is a detail of the retainer in FIG. 7 .
[0024] FIG. 11 is a cross sectional view of the shaft.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0025] FIG. 1 is a cross-sectional view of the tensioner. Tensioner 100 comprises a pulley 7 which engages a belt (not shown) to thereby provide a belt tension or load. Pulley 7 is journalled to arm 6 with a bearing 11 . Pulley is engaged with the bearing outer race. Bearing 11 comprises a ball bearing as shown, but could also comprise a needle bearing or other suitable bearing known in the art.
[0026] Arm 6 is biased by torsion spring 3 thereby urging a pulley 7 into engagement with a belt which applies a tensile load to the belt. Torsion spring 3 is operationally disposed between base 1 and arm 6 .
[0027] Arm 6 pivots about shaft 2 . Pivotal movement of arm 6 allows the tensioner to compensate for any changes in belt length as the belt stretches over time and as the drive length changes from thermal expansion. Arm 6 pivots about a low-friction bushing 10 about shaft 2 . Shaft 2 is press fit into base 1 and extends normally from base 1 .
[0028] Eccentric adjuster 8 is also press fit to the end of shaft 2 opposite base 1 . Eccentric adjuster 8 is used to rotate the tensioner into proper engagement with the belt during installation. Eccentric refers to the center of hole 21 not being coaxial with a center of rotation of pulley 7 or of arm 6 . Eccentric adjuster 8 is used to properly load the belt with a predefined tension by compensating for all component and system tolerances. A tool (not shown) engages the adjuster at tool receiving portion 82 . Eccentric adjuster 8 is used only during belt installation. It is locked in place once the belt is installed by fully engaging a fastener inserted through a hole 21 , 81 into a mounting surface.
[0029] To minimize the amount of arm oscillation or movement during operation friction damping is used. Excessive arm motion induced by the engine vibration could cause the belt to jump a tooth or “ratchet”. Tooth jump or ratcheting of the belt causes a loss of synchronization between the driven and driving shaft(s) of the belt.
[0030] Wave spring 5 is disposed between damping member 13 and arm 6 . Wave spring 5 imparts a normal force upon damping member 13 . Damping member 13 bears frictionally upon base 1 , thereby damping an oscillation of arm 6 . Damping member 13 is generally a toroid in shape, but may also be disk shaped. Torsion spring 3 is compressed between arm 6 and pad 12 . Pad 12 is mechanically engaged with base 1 wherein tangs 120 engage each side of a tab 41 . Being thus engaged pad 12 is constrained against rotation relative to base 1 .
[0031] FIG. 2 is an exploded view of the tensioner. Damping member 13 creates friction damping between arm 6 and base 1 . Damping disk 9 is also used to create friction damping between arm 6 and eccentric adjuster 8 . Frictional surface engages eccentric adjuster 8 . Damping member 13 and damping disk 9 are disposed on axially opposite ends of arm 6 .
[0032] Damping member 13 and damping disk 9 each move rotationally with arm 6 , while base 1 and eccentric adjuster 8 are fixed to the mounting surface, such as an engine (not shown). Pulley surface 71 may be flat, multi-ribbed or toothed to accommodate a suitable belt.
[0033] An end 31 of spring 3 engages tab 41 , wherein tab 41 acts as a reaction point on base 1 . The other end 32 of spring 3 engages arm 6 .
[0034] Rotation of arm 6 is limited by stops 63 coming into contact with a tab 41 .
[0035] FIG. 2 b is a side view of the wave spring. The wave spring comprises multiple coils 51 . Each coil comprises undulations wherein each coil comes into contact with an adjacent coil at a limited number of locations approximately 120° apart. This description is not intended to limit the coil design of the spring. Each spring may have more or fewer undulations per coil depending on design requirements. It may also comprise one or more coils. In an alternate embodiment the wave spring comprises only one coil with ends joined.
[0036] FIG. 3 is an exploded view of the tensioner. Torque from arm 6 is transferred through keyway 61 to tab 130 thereby causing damping member 13 to move in locked unison with arm 6 . Keyway 61 is disposed at an axial end of arm 6 . Base 1 comprises tabs 41 (three are shown) which extend in a substantially axial direction.
[0037] Torque from arm 6 is transferred through keyways 62 . Keyways 62 are disposed at an axial end of arm 6 opposite keyway 61 . Damping disk 9 comprises a tab 91 which extends in the axial direction. Tab 91 engages a keyway 62 . Rotation of arm 6 causes locked rotation of damping disk 9 through interaction of keyway 62 and tab 91 .
[0038] Damping member 13 and damping disk 9 are loaded normally by compression of wave spring 5 thereby creating normal force friction. This arrangement compensates for wear and assembly tolerances. Wave spring 5 is captured between damping member 13 and arm 6 in a receiving portion 63 . Spring 5 rotates with arm 6 ensuring that relative motion only occurs between damping member 13 and base 1 , as well as only between damping disk 9 and eccentric adjuster 8 .
[0039] Spring 5 is shown as a wave spring which is preferred due to its spring rate characteristic and area of surface contact. FIG. 2 b is a side view of the wave spring. In this embodiment spring 5 comprises multiple coils or volutes, each having a wave profile. This allows suitable control of the axial (or normal) force relative to the tolerances of the tensioner assembly. The force of the wave spring in combination with the compression of torsion spring 3 , and further in conjunction with the coefficient of friction of mating parts determines the damping level of the tensioner assembly. In alternate embodiments spring 5 may comprise a single coil wave spring.
[0040] The coefficient of friction of the various mating parts is as follows:
[0000]
Part
CoF
Damping member 13 against base 1
≦0.4
Damping disk 9 against adjuster 8
≦0.4
Damping disk 18 against base 11
≦0.4
Damping disk 19 against arm 20
≦0.4
[0041] Damping member 13 and damping disk 9 may comprise any known frictional material used in a tensioner damping application, including oil resistant metals and polymers. Alternate embodiments may produce sufficient axial force by use of the torsion spring 3 in compression without use of the wave spring. FIG. 6 is a chart illustrating the spring rate (k) as a function of spring height. Total compression is indicated for each spring type, namely, spring washer, wave spring and compression or torsion spring.
[0042] FIG. 4 is a cross-sectional view of an alternate embodiment. FIG. 5 is an exploded view of the alternate embodiment in FIG. 4 . FIGS. 4 and 5 describe an alternate embodiment where a spring loads two damping disks, 18 , 19 , that are fixed to rotate together thereby preventing the need to fix the damping disks to the arm 20 to be dampened. Damping disk 18 is in frictional contact with a static component, base 11 , and the damping disk 19 is in frictional contact with the moving member, arm 20 , to dampen the movement of the arm 20 .
[0043] Eccentric adjuster 15 is an eccentric that is used to move the tensioner into proper engagement with the belt during installation. Eccentric refers to the center of hole 150 not being coaxial with a center of rotation of pulley 14 or of arm 12 . Eccentric adjuster 15 is used to load the belt with a predetermined tension. Eccentric adjuster 15 is used only during belt installation and is locked in place once the belt is installed by fully engaging a fastener (not shown) through a hole 150 with a mounting surface. The fastener may comprise a bolt or any other suitable fastener known in the art.
[0044] Pulley 14 engages a belt to provide belt tension or load. Pulley 14 is journalled to arm 20 about a bearing 141 , Pulley 14 is engaged with the bearing outer race. Bearing 141 comprises a ball bearing as shown, but could also comprise a needle bearing or other suitable bearing known in the art.
[0045] Arm 20 is biased by torsion spring 13 thereby urging pulley 14 into a belt (not shown). Pivotal movement of arm allows the tensioner to compensate for any changes in belt length as the belt stretches over time and as the drive length changes from thermal expansion or as engine load and therefor belt load changes. Arm 20 pivots about a low-friction bushing 16 on shaft 12 . Shaft 12 is fixed to base 1 .
[0046] Motion of arm 20 is damped by frictional contact with damping disk 19 . Damping disk 19 is pressed into arm 20 by O-ring 17 . O-Ring 17 comprises an elastomeric material and is used as a compressible resilient member to apply a normal force to damping disk 19 and damping disk 18 . O-Ring 17 could be replaced by a wave spring, a compression spring, a Belleville spring, or other compressible resilient member having spring characteristics known in the art. Damping disk 18 is pressed by O-Ring 17 into base 11 . Base 11 is fixed to a mounting surface such as an engine (not shown). Frictional surface 193 engages arm 20 . Frictional surface 183 engages base 11 . Damping is created by the resistant torque created by the frictional force of the contact between damping disk 18 and base 11 , and damping disk 19 and arm 20 .
[0047] Each tab 181 on damping disk 18 fits between two cooperating lug(s) 191 on damping disk 19 . This arrangement fixes damping disk 18 and damping disk 19 so there is no relative rotation between the two but allows movement between these two components in the axial direction. Movement in the axial direction allows O-Ring 17 to apply a preload force to both damping disks 18 , 19 and to compensate for manufacturing tolerances and wear. A lip 182 on each tab 181 engages a cooperating rim 192 on damping disk 19 to limit the relative axial movement of the damping disks 18 , 19 by locking them together.
[0048] The assembly of damping disk 18 and damping disk 19 “floats” between the arm 20 and base 11 . Neither damping disk 18 nor damping disk 19 are rotationally fixed to base 11 or arm 20 .
[0049] Retainer 21 holds the assembly together axially. Retainer 21 is fixed to eccentric adjuster 15 and engages shaft 12 to hold the assembly axially.
[0050] FIG. 7 is a detail of the retainer and adjuster. Retainer 21 holds the assembly together when the tensioner is not mounted to an engine. Retainer 21 is attached to adjuster 15 by engagement of posts 151 and holes 211 and prongs 212 . The two posts 151 prevent retainer 21 from rotating and prongs 212 retain retainer 21 on posts 151 . FIG. 10 is a detail of the retainer in FIG. 7 .
[0051] FIG. 8 is a detail of the retainer on the adjuster. The sub-assembly of retainer 21 and adjuster 15 is inserted into shaft 12 . Tabs 213 are resiliently bent inward during assembly to allow retainer 21 to pass through the bore of shaft 12 . Receiving portions 152 provide a space into which tabs 213 are bent. A circumferential groove 121 in shaft 12 allows tabs 213 to resiliently expand outward to lockingly engage shaft 12 . FIG. 9 is a detail of the assembled shaft and adjuster. Relative axial movement of adjuster 15 and shaft 12 is restricted by interaction between the wall of groove 121 and the radially expanded tabs 213 . FIG. 11 is a cross sectional view of the shaft.
[0052] Although a form of the invention has been described herein, it will be obvious to those skilled in the art that variations may be made in the construction and relation of parts and method without departing from the spirit and scope of the invention described herein.
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A tensioner comprising a base, a shaft connected to the base, an eccentric adjuster coaxially engaged with the shaft, an arm pivotally engaged with the shaft, a pulley journalled to the arm, a torsion spring engaged between the arm and the base, the arm comprising a first receiving portion and a second receiving portion disposed axially opposite from the first receiving portion, a first damping member disposed between the arm and the base, the first damping member frictionally engaged with the base and engaged with first receiving portion, a second damping member disposed between the arm and the eccentric adjuster having a member engaged with the second receiving portion, and a biasing member disposed between the first damping member and the arm for applying a normal force to the first damping member and to the second damping member.
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FIELD OF ART
The disclosed device relates to water production and purification, and more particularly to the generation of potable water from atmospheric humidity.
BACKGROUND
The need for water is universal. In many places, reliable sources of clean water are insufficient to meet human needs. The lack of clean water may be due to infrastructure damage, such as the damage to water supply systems caused by an earthquake or flood. The lack of clean water may also be due to migration, such as population displacements into refugee camps during a war.
It is difficult to provide clean water quickly and efficiently. Water is heavy. It can be expensive to transport water to the areas that need it. Digging wells and building water treatment facilities requires time, energy and equipment.
The prior art discloses methods and systems for water collection from atmospheric moisture in small quantities in controlled indoor environments where the temperature is warm and humidity levels are moderate or high.
There is a need for a system that can reliably and quickly provide clean water. The present systems and methods enable the extraction of liquid water from humidity when the dew point is low.
SUMMARY
The present application discloses systems and methods for water collection from atmospheric moisture in large quantities in uncontrolled outdoor environments where the temperature may be cold and humidity levels may be low.
Technical Problem
There are several challenges related to the production and purification of potable water from atmospheric moisture or surface water sources. It is difficult to provide a system that is mobile, easy to set up, modular, capable of functioning without infrastructure-provided water or power, sanitary, designed for multicultural use in its control interface, maintainable with minimal technical skills needed for routine maintenance, rugged enough for use outside when temperatures fluctuate, and capable of producing water from humidity when the dew point is low.
The following embodiments and aspects thereof are described and illustrated in conjunction with systems, tools, and methods which are meant to be exemplary and illustrative, not limiting in scope. In various embodiments, one or more of the above described problems have been reduced or eliminated, while other embodiments are directed to other improvements.
Technical Solution
Several technical solutions are disclosed to address the challenges relating to environmental tolerance, energy efficiency, ease of operation, transport considerations, and operation at low temperature and humidity levels.
The production of potable water for humans and livestock is often needed in outdoor areas. Environmental tolerance is important because the system may be installed outdoors or in facilities without environmental controls. Embodiments of the system are designed to withstand freezing temperatures and function in near-freezing cold. One the technical solutions includes the use of metal filter housings that resist cracking under the pressure exerted by water expansion when the water freezes or heats up.
Embodiments of the system can function outdoors where temperature fluctuations are common. To extract water from air when the dew point is low, the evaporator cools to a point where water vapor is deposited on its surface as ice. The evaporator then cycles through a heating phase to melt the ice and generate liquid water. The accumulation of frost is good. Frost accumulation enables water collection when the dew point is low. The dew point is often low when relative humidity levels are low. Relative humidity is the actual amount of humidity relative to the maximum amount of humidity possible at that same temperature and pressure. The dew point is also often low when air temperatures are low because cooler air does not hold as much moisture. Cycling through frosting and melting allows the system to collect water from ambient air with relative efficiency in conditions that would otherwise be adverse to water production through dehumidification.
Surface water may be contaminated with microbes, heavy metals, chemical byproducts of agriculture, and other contaminants. Through filtration and irradiation these contaminants may be neutralized or removed. Some disclosed embodiments use reverse osmosis, carbon filters, zeolite filters, ozone, and ultraviolet light to produce potable water for consumption.
Embodiments of the system are designed to be resistant to pest animals and insects. Screens cover air vents. Conduit and panels cover wires. Interior spaces are accessible to human inspection.
Energy efficiency is important because the system requires power to function. Power supplies may be limited. In one embodiment, a diesel generator is included. In another embodiment, solar panels are included. In another embodiment, the system uses a wind turbine for energy. In another embodiment power is provided by conventional electrical utility infrastructure. To conserve energy, a variable compressor is used. To further enhance efficiency, the fans are configured to optimize the air flow through the system. Sanitization may be accomplished with ozone, ultraviolet light, chemical addition, heat, microfiltration or combinations thereof. Gravity may assist the flow of liquid water through the filters. Pump activation can be controlled by the programmable logic controller (PLC). The PLC can regulate processes that require power. The PLC may be programmed to optimize energy consumption or to shift energy use from times of the day associated with peak energy consumption to off-peak times. Power optimizing or production optimizing settings may be preprogrammed.
The system may incorporate many features to facilitate use. The human-machine interface may offer multiple languages, allowing a user to select a language, it may also incorporate pictographic icons and touch-screen control. The PLC is designed for multiple inputs and outputs. The PLC is tolerant of extended temperature ranges, immune to electrical noise, and resistant to vibration and impact. Parts of the system requiring periodic replacement or manual adjustment are positioned accessibly.
To facilitate transport, embodiments of the water system are configured to fit into a standard shipping container or onto a standard truck bed. In one embodiment an integrated bottling system is disclosed to facilitate distribution of the water produced.
Advantageous Effects
The combination of features disclosed has an advantageous effect of providing a potable water generating system that can be transported, set up, and used with relative ease and with minimal infrastructure in a broad range of environments.
In addition to the exemplary aspects and embodiments described above, further aspects and embodiments will become apparent by reference to the accompanying drawings forming a part of this specification wherein like reference characters designate corresponding parts in the several views.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a simplified air flow and water path through the system.
FIG. 2 shows a simplified refrigerant flow path in a frosting configuration.
FIG. 3 shows a simplified refrigerant flow path in a defrosting configuration.
FIG. 4 shows an alternate simplified refrigerant flow path in a system where the functionality of the condenser and evaporator may be reversed.
FIG. 5 shows an alternate simplified refrigerant flow path in a system where the functionality of the condenser and evaporator may be reversed.
FIG. 6 shows the simplified system with additional sensors and control modules.
FIG. 7 shows an embodiment of the system with power generation, filtration, water storage, and bottling features incorporated.
FIG. 8 is a flow chart showing a prior art method.
FIG. 9 is a flow chart showing one of the disclosed methods.
FIG. 10 is a flow chart showing an alternate embodiment of the disclosed methods.
FIG. 11 depicts a standard graph of the grains of water vapor per cubic foot held by air when saturated at several temperatures.
FIG. 12 is a prior art chart showing the relationship between dew point, temperature and relative humidity.
Before explaining the disclosed embodiments of the disclosed device in detail, it is to be understood that the device is not limited in its application to the details of the particular arrangements shown, since the device is capable of other embodiments. It is to be understood that the embodiments and figures disclosed herein are intended to be illustrative rather than limiting. Also, the terminology used herein is for the purpose of description and not of limitation.
DETAILED DESCRIPTION
The following description is provided to enable any person skilled in the art to make and use the disclosed apparatus. Various modifications, however, will remain readily apparent to those skilled in the art, since the generic principles of the present apparatus have been defined herein specifically to provide for a system and method for the generation of potable water from atmospheric humidity.
FIG. 1 presents a simplified version of an embodiment showing air and water flow paths. Inflow air 101 enters through a particulate filter 102 . It then passes by a condenser 103 . The condenser 103 is hotter than the inflow air 101 and the air provides a cooling function on working fluid contained in the condenser 103 . The air then passes the evaporator 104 which is cold. Condensate or frost forms on the evaporator 104 . The fan unit 105 then blows the dehumidified air 107 out the air exit 106 .
Unprocessed water 108 is collected in the water collector 109 and directed to the collection vessel 110 . The collected water pump 111 pushes water through a first filter 112 and a second filter 113 . Additional filters may be used to achieve the desired result. Many types of filters provide beneficial effect. For example: reverse osmosis filers, activated carbon filters, resin filters, ion exchange filters, adsorption filters, ultrafiltration membrane filters, microporous ceramic filters, zeolite filters, diatomaceous earth filters, and particulate filters.
After filtration, water enters the holding vessel 114 . In the holding vessel 114 , water safety may be facilitated by a sanitizing ultra violet (uv) device 115 , an ozone device 117 , or by the addition of chemicals such as chlorine compounds. Water may be drawn from the holding vessel 114 through a purified water outlet valve 116 . If it is desired to use the system for filtration of available liquid water, the liquid water may be added to the system through an optional grey-water inlet 118 .
FIGS. 2 and 3 show one embodiment in two configurations. FIG. 2 shows a simplified refrigerant flow path in a frosting configuration, while FIG. 3 shows a defrosting configuration. Working fluid, or refrigerant, is shown traveling in a loop. Thick lines with arrows show the flow path.
In FIG. 2 , refrigerant flows through the evaporator 104 , through the compressor 201 , through the condenser 103 , through an expansion device 202 , and back through the evaporator 104 . Fluid passing through the expansion device 202 expands as pressure is reduced. This expansion is generally accompanied by a phase change; the refrigerant goes from a liquid to a gas and it absorbs heat, cooling the exterior of the evaporator 104 . In FIG. 2 the bypass valve 203 is closed and there is no flow through the bypass shunt 204 .
In FIG. 3 , the bypass valve 203 is open and refrigerant from the compressor 201 flows through the bypass shunt 204 . Fluid exits the compressor 201 at a high temperature. The hot fluid passes through the bypass valve 203 and bypass shunt 204 relatively unchanged in pressure and temperature. Thus, it is hot when it enters the evaporator 104 and it melts ice that may have formed on the evaporator 104 .
FIGS. 4 and 5 show an alternate simplified refrigerant flow path in a system where the functionality of the condenser and evaporator may be reversed. In this embodiment there is a flow-directing valve 401 shown here as a four-way valve. The expansion device 202 may incorporate one or more capillaries 402 . The flow can be reversed so that the evaporator 104 and condenser 103 can switch function. The flow-directing valve 401 changes the flow path to do this. The flow-directing valve 401 , shown here as a four-way valve, connects the compressor flow circuit 403 to the heat exchangers selectively determining the path of the working fluid.
FIG. 6 shows the simplified system of FIG. 1 with additional sensors and control modules. These include: a frost sensor 601 , an intake humidity sensor 602 , an intake temperature sensor 603 , a collection vessel level sensor 604 , a holding vessel level sensor 605 , and a regulator or controller 606 . Various controllers and/or regulators may take input from the optional sensors. The various controllers and regulators can control aspects of the system such as the evaporator temperature, the valves, the expansion device, the compressor speed, the fans 105 , the collected water pump 111 , and other aspects of the system as discussed hereinafter.
FIG. 7 shows an embodiment of the system with power generation, filtration, water storage, and bottling features incorporated within the bounds of a standard 20-foot freight container. The integrated system includes at least one atmospheric water unit 701 , diesel generator 702 , shipping container boundary wall 703 with apertures for air flow 711 , and at least one door 707 . The integrated unit may also comprise a water bottling, filling, and capping unit 704 having an input conveyor 705 and a bottle output conveyor 706 . The fuel storage 708 is segregated from the airflow intake areas by one or more boundary walls 703 to avoid contamination by fumes. There is also an electrical control 709 and a maintenance passage 710 .
FIG. 8 shows a prior art method for operating prior art atmospheric water generators. Analogous systems are known in the art of similar systems in the field of refrigeration and air conditioning. In these prior art systems, frost on the evaporator is not desired because frost may obstruct air flow. The prior art method shown in FIG. 8 begins with the prior art initiation step 801 , a first input step is in the form of a frost sensor signal 802 , a decision point of frost detection 803 follows. If frost is not detected the refrigeration continues or repeats. If frost is detected, the defrost cycle 804 is initiated.
FIG. 9 shows one of the disclosed methods where frost is desired. It starts with a frost cycle initiation step 901 , a first input step is in the form of a frost sensor signal 802 , a decision point of frost detection 803 follows. If frost is not detected the cooling cycle continues or repeats. If frost is detected, the frost accumulation timer 902 starts, followed by the melt cycle 903 . Melted frost is collected as water. The method steps may be repeated as many times as needed to collect the desired quantity of water.
It is contemplated that frost cycle initiation step 901 comprises starting of compressor 201 and allowing frost to form on evaporator 104 . Melt cycle 903 comprises stopping of compressor 201 after frost has accumulated for a predetermined amount of time, allowing a predetermined amount of time to pass is allowed to pass, activating bypass valve 203 thereby switching condenser 103 and evaporator 104 , restarting compressor 201 and allowing defrosting to occur. Melt cycle 903 further comprises stopping compressor 201 , allowing a predetermined amount of time to pass and deactivating bypass valve 203 so the system may repeat the process, namely commencing step 901 .
FIG. 10 depicts an alternate method of extracting liquid water from humidity by means of frosting. It is contemplated that melt cycle 903 b comprises the operation of the system without the stopping and/or restarting of compressor 201 . Similar to the process shown in FIG. 9 , frost cycle initiation step 901 comprises starting of compressor 201 and allowing frost to form on evaporator 104 . In this example bypass valve 203 b is a one-way valve which can be automatically activated after frost has accumulated for a predetermined amount of time. Here, switching of condenser 103 and evaporator 104 occurs without having to turn the compressor on or off. Switching of condenser 103 and evaporator 104 occurs by activating and deactivating bypass valve 203 b . In melt cycle 903 b defrosting is allowed to occur. Deactivating bypass valve 203 b causes the valve to close, thereby switching condenser 103 and evaporator 104 to allow frosting to occur. This embodiment saves time and the enables the system to increase water output.
It is contemplated that bypass valve 203 , 203 b serves to balance the refrigerant pressure as quickly as possible during the refrigerant exchange from condenser 103 and evaporator 104 . Bypass valve 203 b helps to prevent potential damage to compressor 103 which in some embodiments must undergo a starting process, a stopping process and a restarting process.
Generally referring to FIGS. 1-10 : Air flows into the system. It is dehumidified and then exits the system. In many embodiments, the air flows through a particulate filter, then past a condenser, then past an evaporator, then through the fan area, and finally exiting the system.
A compressor circulates refrigerant or working fluid through a condenser, through an expansion device such as an expansion valve or an adjustable capillary valve, and then through an evaporator, often configured as a finned evaporator coil. Expansion of the working fluid as it passes through the expansion valve into the evaporator results in a state change of the working fluid from a liquid to a gas and the working fluid absorbs heat, cooling the evaporator.
Air passing by the evaporator is cooled. This lowers the air temperature to or below its dew point, causing water to condense. If the evaporator temperature is sufficiently low, the air drops to or below the frost point, causing deposition of frost on the exterior surface of the evaporator. A fan pushes filtered air over the evaporator. Water is collected from the condensate that drips off of the evaporator or by melting the frost on the evaporator and collecting the melt-water. The resulting water is then passed into a holding tank and is further purified, filtered, and treated to produce potable water.
In many embodiments, the air flows first past the condenser coils and then past the evaporator coils. The condenser is hot. The air flow helps to cool the working fluid inside the condenser. Condenser fins also help dissipate heat. The air flowing past the evaporator is cooled. Evaporator fins provide a large surface area for condensation and frost deposition. In one embodiment, there are several capillary tubes directing refrigerant to multiple evaporator segments help to make the gas expand in the evaporator and make it cool more efficiently. Compound evaporators and condensers may be used, and fins on both aid in heat transfer.
The capillary and expansion valve function as expansion devices and can be combined. Both adjust the refrigerant pressure. One important difference is that the capillary capacity for adjusting the pressure is static and the expansion valve capacity is dynamic. Once a capillary is brazed in the system, its capacity is fixed by its length and inside diameter, those factors cannot be adjusted during operation. The expansion valve may have a variable aperture or it may be opened to a single fixed diameter in a series of pulses. Using a single open diameter, the valve is controlled by pulses in a similar principle as controlling a step motor. The expansion valve controls the evaporator temperature according to the detected environmental temperature and humidity, through the PLC program. The PLC sends a pulse to the expansion valve, with more pulse, the valve opens more; less pulse and the expansion valve opens less.
When the evaporator is very cold, frost accumulates on the exterior surface and fins of the evaporator.
The flow path of working fluid is changed to defrost the evaporator. The flow path may have a bypass directly from the condenser routing hot working fluid through the evaporator. Alternately, the flow path through the system may be reversed. The frost is melted from the fins and then the cycle is restated. The evaporator is again cooled until frost forms. The cooling cycle continues so that more frost accumulates on the evaporator fins. The rate of frost accumulation may slow as the frost obstructs airflow. The valves then redirect warm working fluid through the evaporator and frost is melted and then the cooling cycle starts again.
To efficiently collect water from the humidity of air, the evaporator surface temperature must be about 2° C. to about 3° C. lower than the dew point or frost point. Dew point is related to environment temperature, humidity, and pressure. Generally, when the environment temperature is lower than about 15° C. and the humidity is lower than about 40%, the dew point is near, or lower than about 0° C. When the dew point or frost point nears about 0° C., the evaporator surface temperature is reduced to near or below about 0° C. Then, frost, rather than condensate forms on the evaporator. In many embodiments, one or more sensors are used to measure environment temperature and humidity. The approximate frost point or dew point is calculated and the evaporator temperature is adjusted accordingly to run in either the condensate mode or in the frost and defrost cycle mode.
In some embodiments, a sensor mounted on the evaporator measures its surface temperature. If the temperature is lower than about −2° C., the system will start defrosting automatically after a set period of time. The frost time may be set at approximately 30 minutes. At which point the frost thickness is thick enough and the system will start defrosting, melting the frost and generating water. In some embodiments the frost period may be shortened to as short as about 5 minutes in response to higher humidity or lengthened to as long as about two hours in response to lower humidity. In other embodiments, a sensor detects frost thickness and initiates the melting cycle. In embodiments that detect frost thickness, the melting cycle is initiated when the sensor detects a predetermined frost level. The frost level will generally be set at a frost thickness of at least about 1 mm and less than about one half of the distance between evaporator fins. In many embodiments, a desired range will be between about 2 mm to about 6 mm of frost.
In another embodiment, the condenser and evaporator may switch functionality by reversing the flow of refrigerant through the system. Both the condenser and evaporator are heat exchangers. Essentially the system comprises a loop: heat exchanger→compressor→other heat exchanger→expansion device, and back to the beginning. By selectively routing refrigerant from one of the heat exchangers to the compressor, and then to the other heat exchanger, using a four-way valve to switch the sequence, the system can melt ice from one heat exchanger while frosting or promoting condensate on the other.
In other embodiments, a bypass valve may work in parallel with the expansion valve. In such cases, the bypass valve operates during the defrosting process thereby increasing the efficiency of the frosting/defrosting process.
The fans may be placed anywhere along the air flow path such that the fans perform either by sucking or by blowing air past the evaporator. A single fan or a large fan assembly may be used. In some embodiments, a tubular fan assembly promotes efficient air flow. The fans are arranged parallel to the evaporator with all fans in the assembly equidistant from the evaporator. The tubular fan is one kind of cross flow fan, which has a long and narrow shape, so it is relatively easy to mount, it sits close to the condenser surface, and several in parallel may be located to nearly-uniformly direct air past a large area of a heat exchanger. Other types and configurations of fans may be used including cross flow fans, centrifugal blowers, and axial flow fans.
Many embodiments of the system incorporate an integrated filtration system. Filtration may include reverse osmosis filters, carbon filters, resin filters, and particulate filters. Water processing may include re-mineralization, pH adjustment, chlorination, and fluoridation. The filtration system is fully optional for systems designed to provide water to livestock.
Some additional features may include carbonation for sparkling water, heated water, chilled water, and water with flavorings and nutrients. Flavorings and nutrients may include broth, tea, coffee, herbal extracts, minerals, and vitamins. Optional features may be included at or just prior to dispensing. Heating and chilling features may be efficiently designed to take advantage of the heat properties of the evaporator and condenser.
The system may incorporate a power generation unit, such as solar panels, a wind turbine, or a diesel generator. The system may include a bottling feature. Some embodiments are designed to be self-contained units within a standard size shipping container. These embodiments are particularly useful for quickly responding to a humanitarian crisis because they are self-contained and require minimal set-up. They also require no water or power infrastructure.
Some embodiments may produce potable water from either atmospheric moisture or by filtering available liquid water sources. Such sources may include, grey-water, surface water such as that from lakes or streams, and compromised municipal water. These dual-use systems utilize the same filtration system. These dual input systems are designed to permit addition of liquid water into the collection vessel.
FIG. 11 illustrates how moisture content increases with temperature. The shading depicts the area in which the disclosed system may generate water. FIG. 12 is a typical chart showing the relationship between dew point and temperature for several levels of relative humidity and illustrates the conditions at which the disclosed system may generate water.
While a number of exemplary aspects and embodiments have been discussed above, those of skill in the art will recognize certain modifications, permutations, additions and sub-combinations therefore. It is therefore intended that the following appended claims hereinafter introduced are interpreted to include all such modifications, permutations, additions and sub-combinations are within their true spirit and scope. Each apparatus embodiment described herein has numerous equivalents.
The terms and expressions which have been employed are used as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the subjection matters claimed. Thus, it should be understood that although the present systems and methods have been specifically disclosed by preferred embodiments and optional features, modification and variation of the concepts herein disclosed may be resorted to by those skilled in the art, and that such modifications and variations are considered to be within the scope of this subject matter as defined by the appended claims. Whenever a range is given in the specification, all intermediate ranges and sub-ranges, as well as all individual values included in the ranges given are intended to be included in the disclosure. When a Markush group or other grouping is used herein, all individual members of the group and all combinations and sub-combinations possible of the group are intended to be individually included in the disclosure.
Although the disclosed device and method have been described with reference to disclosed embodiments, numerous modifications and variations can be made and still the result will come within the scope of the disclosure. No limitation with respect to the specific embodiments disclosed herein is intended or should be inferred.
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Systems and methods are disclosed for water collection from atmospheric moisture in large quantities in uncontrolled outdoor environments where the temperature may be cold and humidity levels low. To extract water from air when the dew point is low, a heat exchanger cools to a point where water vapor is deposited on its surface as ice. The heat exchanger then cycles through a heating phase to melt the ice and generate liquid water. The accumulation of frost is advantageous. Frost accumulation enables water collection when the dew point is low. Disclosed variations enhance efficiency and environmental tolerance.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention is concerned with wiring structures for use in electronic materials and more particularly with a method of producing such wiring structures in which a specified step process is incorporated to refill, by the bias ECR-CVD system (electron cyclotron reasonance-chemical vapor deposition), a selected metal of electrical conductivity into a connecting hole or aperture on a substrate.
2. Description of the Prior Art
Great concern has been directed toward minuteness and compactness in industrial sectors of electronic materials provided with wirings, such as for example semiconductive devices. The disclosures associated with semiconductors of such a minute and compact type are found for instance in JP-A 64-23554 and JP-A 64-10629. To cope with this trend, wiring structures to be assembled with semiconductors are required to be of reduced width. Minuteness requirements are made necessary and profound for those wirings obtained by refilling connecting holes commonly called contact holes or bearing holes. A keen demand therefore has been voiced for a means of enabling an electrically conductive material to be refilled into narrower connecting holes with utmost reliability.
Taking the above problem in view, it has been proposed to use as electrically conductive materials high melting point metals of sufficient heat resistance and great reliability among which tungsten (W) is typified. The W metal may preferably be turned into the form of films by the blanket W-CVD system in which a total wiring area to be coated is covered with a W film and thereafter is subjected to patterning. This system allows simultaneously for refilling of the connecting hole and for formation of the ultimate wiring and moreover exhibits process stability at a high level in contrast to the selective CVD system also for use in hole refilling. With use of the blanket W-CVD system now mentioned, W can be made into films with low resistance as compared to the sputtering system. Details with respect to those systems are taught in JP-A-62-219945.
The above blanket W-CVD is not necessarily satisfactory as it is susceptible in some cases to insufficient refilling. This is true for instance where a W plug is derived by refilling the connecting hole on a substrate, coupled with formation of a wiring by depositing W over the surface of the substrate. In that instance the connecting holes, if of great aspect ratios and hence layer depths, cause, due to inadequate step coverage during CVD, porous or void refilling.
Alternatively, the bias ECR-CVD system is known for the formation of a blanket W so as to improve hole refilling. This prior system, however, leaves the problem that the blanket W tends to be held adversely thick on the flat surface of the substrate.
SUMMARY OF THE INVENTION
With the foregoing drawbacks of the prior art in view, the present invention seeks to provide a method for the production of wiring structures which enables refilling of an electrically conductive material into a connecting hole by means of the bias ECR-CVD system without involving objectionable voidness and adverse thickness of blanket W on a substrate.
The process according to the invention is applicable to producing wiring structures particularly for use in semiconductive devices and various other electronic materials.
In one aspect, the invention provides a method for the production of wiring structures which comprise preparing a substrate including a base plate and an interlaminar film having disposed therein a connecting hole containing a shoulder portion, and refilling an electrically conductive material into the connecting hole by the bias ECR-CVD system such that the deposition rate is equal to the etch rate at the shoulder portion.
In another aspect the invention seeks to provides a method of the production of wiring structures which comprises preparing a substrate including a base plate and an interlaminar film having disposed therein a connecting hole containing a shoulder portion, and refilling an electrically conductive material into the connecting hole by the bias ECR-CVD system such that the deposition rate is greater than the etch rate at the shoulder portion.
Many other objectives and advantages of the invention will be better understood from the following description taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1(a) to 1(d) are schematic cross-sectional views of the process steps of a first embodiment provided in accordance with the present invention;
FIGS. 2(a) to 2(e) are views similar to FIGS. 1(a) to 1(d) but showing the process steps of a second embodiment;
FIG. 3 is a plan view explanatory of the second embodiment; and
FIGS. 4(a) to 4(f), 5(a) to 5(f), 6(a) to 6(c), 7(a) to 7(e) and 8(a) to 8(f) are schematic cross-sectional views showing the process steps of third, fourth, fifth, sixth and seventh embodiments, respectively, provided in accordance with the present invention.
DETAILED DESCRIPTION OF THE INVENTION
According to the method of the present invention an electrically conductive material is refilled, by the bias electron cyclotron resonance-chemical vapor deposition system (bias ECR-CVD system), into the connector or contacting holes or apertures provided with angled or shouldered portions and positioned on a substrate. Refilling should importantly be done with the deposition rate made equal to the etch rate at these shoulders so that voidless apertures are attained.
Also importantly, the rates of deposition and etching should be adjusted to laminate the electrically conductive material to a desired thickness on the substrate.
The invention will now be described by way of the following examples taken in connection with the drawing representations. These examples should be regarded as illustrative but not as restrictive.
EXAMPLE 1
A wiring structure shown in FIGS. 1(a) to 1(d) is constructed to be used for minute and compact semiconductors such as SRAMs of a 16- or 32-megabit class.
A substrate 1 is formed by a base plate 11 and an interlaminar layer 12 disposed thereon, an SiO 2 film exemplified herein. Designated at 2 is an aperture defined as a contacting hole in the interlaminar layer 12 and derived by patterning the layer 12 by the photolithography-etching system. An impurity area 10, an N + area, is so arranged as to locate on the base plate 11 and communicate with the aperture 2.
An electrically conductive material, typified by tungsten (W), is thereafter refilled into the aperture 2 by the bias ECR-CVD system. In this instance, refilling of the aperture 2 and CVD of W on to the base plate 11 are carried out in a simultaneous manner. To form a layer of W, a bonding layer is generally disposed on the substrate 1 which is chosen from layers of TiN and sputtered W. Such a bonding layer has been arranged but not shown in this example.
The aperture 2 is allowed to refill with the W material at the shoulder or corner portion with the deposition and etching held at one and the same rate by means of the bias ECR-CVD system. This mode of refilling contributes greatly to voidlessness in the aperture 2. Further, one W layer 31a is formed transversely thick as a projection located upwardly from the substrate 1 at 13 in FIG. 1(b), coupled with formation of another W layer 31b of the same thickness as the layer 31a in a flat state in FIG. 1(b). The aperture 2 is set at not more than 1.79, preferably smaller than 1.78, in terms of the aspect ratio defined by the opening depth relative to the opening diameter. The aspect ratios exceeding 1.79 would cause objectionably void refilling in the contact hole 2 and adversely thick lamination of the W layer 31b on the flat site 14.
CVD is effected at a greater rate of deposition than of etching at a flat portion seen at 15 in FIG. 1(c) so that an electrically conductive layer 32 is formed by additionally laminating a film of W to a thickness of l as illustrated in FIG. 1(c). Because this is done with the etch rate set to be greater than the deposition rate at the shoulder portion, the layer 32 is detracted slightly toward the left and right sides as viewed at 33 in FIG. 1(c) due to the effect of leveling.
With the detracted parts 33 held in alignment with a resist, an electrically conductive film 34 of a thickness of l is disposed as corresponding to the projection 13 shown in FIG. 1(b). The resulting structure is viewed in FIG. 1(d) in which numberal 6 is used to refer to a resist and 33' to a W portion removed by masking with the resist.
By implementing this example, reliable refilling of the aperture even if relatively large in aspect ratio can be achieved without a thick lamination of the wiring layer being caused. Also advantageously, contact hole refilling and wiring layer formation are simultaneously possible.
EXAMPLE 2
This example also illustrates a wiring structure for application to highly compact semiconductors.
A blanket W layer or wiring material layer 30 is laminated by the CVD system, such as of a thermal type in this example, over a substrate 1 made up of a silicone base plate 11 and an interlaminar SiO 2 film 12. The wiring layer 30 may be formed by the sputtering system as no specific coverage is required. Disposed on the layer 30 is a reflection-inhibiting film 4 of about 300 Å in thickness made of TiON or the like. The structure thus formed is seen in FIG. 2(a). To improve bonding of the wiring layer 30 to the substrate, a heat-resistant layer of TiN or sputtered W is interposed therebetween. Such an intermediate layer is omitted for simplicity in FIGS. 2(a) to 2(e).
Patterning is subsequently done to form an aperture 2, namely a contacting or bearing hole, by the lithography system in common use in which both the wiring layer 30 and the interlaminar layer 12 are subjected to the reactive ion etching system (RIE). Where the aperture 2 is a contact hole, the intermediate layer 12 is caused at its extremely thin, last interface to undergo RIE under lowly ionized energy conditions to thereby prevent W against knocking on. This facilitates selection of the ratio of Si on the silicone plate 11, meaning that etching may employ a fluorine type gas under the above conditions. For instance, the reflection-inhibiting film 12 may be etched with a highly ionic gas such as SF 6 /Cl 2 or SF 6 /N 2 , followed by RIE of the interlaminar film 12 at its last interface under low ionic energetic conditions. Thus a structure is obtained as represented in FIG. 2(b).
Refilling of the aperture 2 is performed by the bias ECR-CVD system for example with the deposition and etch rates made equal to each other at the aperture shoulder. A structure as seen in FIG. 2(c) is obtained in which the aperture 2 is refilled with an electrically conductive material 51 along with formation of an electrically conductive layer 52. The conditions are given below.
gas: SiH 4 /N 2 O=20/30 SCCM
microwave: 1.0 kW
RF bias: 0.5 kW
pressure: 7×10 -4 Torr
magnetic field: 875 Gauss
The electrically conductive layer 52 is then subjected to the bias ECR-CVD system so as to gain the effect of leveling. A structure viewed in FIG. 2(d) is thus obtained in which an electrically conductive material 51 refilled in the aperture 2 is separated from a similar material 52 located on TiO of the reflection-inhibiting layer 4. Leveling may be effected for example under the conditions summarized below.
gas SiH 4 /N 2 O=7.5/35 SCCM
pressure: 7×10 -4 Torr
microwave: 1.0 kW
RF bias: 0.5 kW
By means of patterning, a resist pattern 6 is formed which is used to mask and remove the relatively wide layer 52 as shown in dotted line in FIG. 2(e). Removal of the layer 52 may be made, for example, by wet etching in which a mixture of sulfuric acid and hydrogen peroxide is used or by plasma etching in which F + is used with its ionization reduced by an SF 6 gas.
Wiring or patterning is done on the layer 52 by the lithography system. Due to the presence of the film 4, patterning is free from structural deterioration by light reflectance. Although no reflection-inhibiting film is disposed over the aperture 2, no problem arises as the resist pattern 6 is patterned to cover the aperture 2 as better seen in FIG. 3.
Voidless refilling of the aperture 2 with an electrically conductive material, W in this example, is achieved by the bias ECR-CVD system, forming the wiring layer 30 and then the reflection-inhibiting film 4, and subsequently by leveling the layer 52 to thereby remove the layer 52. The film 4 acts to remove excess W material, leading to a good wiring pattern.
EXAMPLE 3
With reference to FIGS. 4(a) to 4(f), an electrically conductive layer or blanket W layer 31 is laminated, by the bias ECR-CVD system, on a substrate 1 constructed with a base plate 11 and an interlaminar layer 12 in which is disposed an aperture 2 such as a contact hole or bearing hole. Designated at 3 is W refilled in the aperture 2. Though not shown, a bonding film such as of TiN is located beneath the blanket W layer 31.
The W layer 31 is formed under the following conditions.
gas: WF 6 /SiH 4 /H 2 /Ar=20/30/100/50 SCCM
RF bias: 500 W
pressure: 7×10 -4 Torr
magnetic field: 875 Gauss
The structure thus obtained is as viewed in FIG. 4(a). CVD is then done under the leveling conditions mentioned above with the result that a widely horizontal, electrically conductive layer 32 is separated from the W material 3 refilled in the aperture 2 as shown in FIG. 4(b).
CVD is based on the conditions given below.
gas SiH 4 /N 2 O=7.5/35 SCCM
pressure: 7×10 -4 Torr
microwave: 1 kW
RF bias: 0.5 kW
As an etch-protective portion 7, SiO 2 , is thereafter formed by the liquid phase CVD system in a recess 60 derived from leveling as shown in FIG. 4(c) in which SiO 2 is fully stored in the recess 60 owing to the liquid phase system. For this purpose, an admixture of TEOS/O 2 may be employed as liquid phase CVD.
Isotropic etching is performed to remove the blanket W layer 32 not covered with the etch-protective portion 7 or SiO 2 . There may be applied a wet etching system in which an H 2 SO 4 /H 2 O 2 solution is used or a plasma etching system in which a fluorine or F + radical is used. In the case where F + is used, a bonding layer of TiN is preferred to be disposed which is unlikely to be etched and hence useful as a stopper. An etching stopper may be arranged where desired.
The blanket W layer 32 alone can be removed by isotropic etching as the leveling operation has previously been completed as shown in FIG. 4(b).
Subsequently, the etch-protective layer 7 or SiO 2 is removed as by RF. A bonding layer of TiN if present is useful as a stopper. A suitable etching stopper may if necessary be arranged. The resulting structure is as represented in FIG. 4(e).
Blanket W is laminated as a wiring layer 36 on the substrate 1 for example by means of thermal CVD, PE-CVD, ECR-CVD or photo assisted CVD. Sputtering may be employed as refilling is not called for in this stage of process. The structure thus formed is illustrated in FIG. 4(f) in which blanket W is laid throughout the width of the substrate.
To effect aperture refilling leading to the refilled W 3 and wiring formation leading to the blanket W layer 31 by means of bias ECR-CVD system, this example permits easy removal of the widely horizontal, electrically conductive layer 32. The reason is due to use of the masking layer 7 resulting from CVD. Continuous processing is also made possible with a vacuum state maintained.
EXAMPLE 4
Reference is made to FIGS. 5(a) to 5(f). An electrically conductive layer or blanket W layer 31 is disposed, by the bias ECR-CVD system, on a substrate 1 made up of a base plate 11 and an interlaminar film 12 provided with an aperture 2 such as a contact hole or bearing hole. The W layer 31 is laid over a bonding layer such as TiN, not shown, located on a widely horizontal wiring surface of the substrate 1 and on the interlaminar layer 12. The aperture is refilled with W, simultaneously with formation of the layer 31, as seen at 3 in FIG. 5(a). The blanket W-CVD conditions are given below.
gas: WF 6 /SiH 4 /H 2 /Ar=20/30/100/50 SCCM
microwave: 1 kW
RF bias: 0.5 kW
pressure: 7×10 -4 Torr
magnetic field: 875 Gauss
The resultant structure is as illustrated in FIG. 5(a). A widely horizontal, electrically conductive layer 32 is separated, by leveling, from the W material 3 refilled in the aperture 2.
The leveling conditions are given below.
gas: SiH 4 /N 2 =7.5/30 SCCM
pressure: 7×10 -4 Torr
microwave: 1 kW
RF bias: 0.5 kW
FIG. 5(b) illustrates a structure resulting from the operation of leveling in which the W material 3, the layer 31 and the layer 32 separate with one another. Coating of resists of low viscosity is accomplished, followed by isotropic etching by O 2 RIE in this example, so that the resists 61, 62 are held in recesses 60 formed in FIG. 5(b). The resultant structure is shown in FIG. 5(c) in which the resists are accommodated in the recesses alone.
The blanket W layer 32 not covered with the resists 61, 62 is removed by isotropic etching such as a wet etching system in which an H 2 SO 4 /H 2 O 2 solution is used or a plasma etching system in which a fluorine radical F + is used. When F + is used, TiN is preferably located as a bonding layer, which TiN is rendered less etchable and hence utilized as a stopper. An etching stopper may be arranged when desired.
Because the operation of leveling has been completed as seen in FIG. 5(b), only the blanket W layer 32 can be removed after which a structure is formed as illustrated in FIG. 5(d).
The resists 61, 62 are thereafter removed as by O 2 ashing. Thus there is obtained a structure as shown in FIG. 5(e).
A wiring layer 36 is formed over the substrate 1 as by thermal CVD, PE-CVD, ECR-CVD or photo assisted CVD. Sputtering is also feasible as refilling is not necessary at this stage. The structure thus obtained is provided with blanket W throughout the width of the substrate as viewed in FIG. 5(f).
In attaining refilling of the aperture 2 and formation of the blanket W layer 31 with use of the bias ECR-CVD system, it is made possible to easily remove the W material in a wide region as the blanket W layer 32 is masked with the resists 61, 62. To refill the recesses 60, a suitable leveling polymer may be used in place of the resists 61, 62. Such polymer should exhibit high fluidity even at low temperature and uniform surface upon coating, including for example styrene-chloromethylstyrene copolymer and siloxane-containing polymer. Details with respect to the polymer are published in an issue of Jan. 4, 1990, Nikkan Kogyo Shimbun.
EXAMPLE 5
Reference is made to FIGS. 6(a) to 6(c). A contact hole or aperture 2 is disposed in a region on which to form a wiring on a substrate 1 comprised of a base plate 11 and an interlaminar film 12. The aperture 12 is refilled by deposition of blanket W with use of the bias ECR-CVD system. Refilling is done such that the etch rate is made equal to the deposition rate at an upper or shoulder portion of the aperture 2. The resulting structure is shown in FIG. 6(a) in which a recess 60 is formed in an electrically conductive or W layer 31. Seen at 3 in FIG. 6(a) is W deposited in the aperture 2.
Bias ECR-CVD is carried out under the conditions given below.
gas: SiH 4 /N 2 O=17.5/30 SCCM
microwave: 1 kW
RF bias: 0.5 kW
pressure: 7×10 -4 Torr
magnetic field: 875 Gauss
In the structure of FIG. 6(a) the recess 60 is refilled by liquid phase CVD system into a flat form as illustrated at 7 in FIG. 6(b), namely in a manner in which the W level is held in parallel relation to the surface of the layer 31 owing to the liquid phase system being used.
The layer 31 on its overall surface is caused to undergo anisotropic back etching so as to set a given wiring layer 31' at a predetermined thickness of l. The layer 31' is then patterned into a desired wiring structure.
To simultaneously achieve aperture refilling and wiring formation, refilling is completed by bias ECR-CVD, followed by leveling on liquid phase CVD and by subsequent back etching. This is highly capable of leveling and matching the electrically conductive layer or W wiring with utmost ease. Thick wiring is a serious disadvantage peculiar to the wiring formation by bias ECR-CVD. In this example a plurality of chambers may be arranged to continuously effect bias ECR-CVD, liquid phase CVD and RIE back etching in the order mentioned. Throughput is greatly improved.
EXAMPLE 6
FIGS. 7(a) to 7(e) refer to this example. Laminated over a base plate 11 is an interlaminar or SiO 2 layer 12, and an aperture 2 such as a contact hole or bearing hole is contrived to be patterned by lithography. The layer 12 is subjected to RIE to thereby form an aperture 2. A substrate 1 is thus constructed as shown in FIG. 7(a).
By bias ECR-CVD, the aperture 2 is refilled with W as an electrically conductive material. A blanket W layer is formed in this example over a bonding layer not shown. The deposit rate is set to be slightly greater than the etch rate at the upper or shoulder portion of the aperture 2.
The following conditions are applied to arrangement of the blanket W layer
gas: WF 6 /H 2 /Ar=10/40/20 SCCM
microwave: 0.3 kW
pressure: 5×10 -3 Torr
magnetic field: 875 Gauss
Through the above process steps a structure is obtained as shown in FIG. 7(b) in which an electrically conductive layer 54 is provided therein with a recess 5'. Leveling is done as in the foregoing examples so that the recess 5' is cut outwardly but without the layer 54 etched in the vertical and lateral directions. Illustrated in FIG. 7(c) is a structure derived by the operation of leveling in which the cut portions of the recess 5' are designated at 56 and laterally cut, W defined layers at 55.
Leveling is conducted under a set of conditions given below.
gas: SiH 4 /N 2 =7.5/35 SCCM
pressure: 7×10 -4 Torr
microwave: 1 kW
RF bias: 0.5 kW
SiO 2 is patterned to form a resist pattern 6 as shown in FIG. 7(d) after which the W material is removed in a wide region at 57 as by a wet etching system in which is used an H 2 SO 4 /H 2 O 2 solution or a plasma etching system in which is used a flourine radical F + .
Upon removal of the resist pattern as treated above, a portion 59 is derived, as illustrated in FIG. 7(e), which portion corresponds to a size of Å of an aperture refilled portion 58 but has two outwardly marginal extensions B, B.
This leads to a wide selectively of wiring formation.
To form and refill the aperture 2 with an electrically conductive material, a W material in this example, the deposition rate is set to be slightly greater than the etch rate at a shouldered or angled portion of the aperture 2. Further, leveling is done by removing the W material at a wide region. This occurs in voidless fashion and a stable refilling of the aperture 2 results at a slightly higher rate of deposition than of etching without the aperture becoming cut at its angled portion. The marginal portions B, B are advantageous in matching in wiring formation.
EXAMPLE 7
This example is explained with reference to FIGS. 8(a) to 8(f). An aperture 2 such as a contact hole or bear hole is formed by patterning an interlaminar layer 12 with use of lithography, which layer is used to constitute a substrate 1. Formation of the aperture 2 results from RIE of the layer 12, leading to a structure of FIG. 8(a).
A W material is deposited by the bias ECR-CVD system so as to form an electrically conductive layer 31. CVD is effected at a higher rate of deposition than of etching, as for instance under the following conditions.
gas: WF 6 /H 2 /Ar=10/40/20 SCCM
microwave: 0.8 kW
RF bias: 0.3 kW
pressure: 5×10 -4 Torr
magnetic field: 875 Gauss
As illustrated in FIG. 8(b) a structure is obtained in which a recess 80 is deposed over the aperture 2. Subsequent leveling allows the layer 81 to detract at its left and right sides. This condition is seen at 82 in FIG. (c).
The leveling conditions may be set below.
gas SiH 4 /N 2 =7.5/35 SCCM
pressure: 7×10 -4 Torr
microwave: 1 kW
RF bias: 0.5 kW
Leveling compensates for margins to be taken in the subsequent resist matching as shown in FIG. 8(e). When it is found desirable, this step of leveling may be supplemented. An electrically conductive layer 84 is removed by anisotropic etching such that it is made coextensive with the surface of the aperture 2 as seen in FIG. 8(d). In this case an electrically conductive material or W 85 is held in the aperture 2 alone. Designated at 84 is a portion anisotropically etched and at 83 is an electically conductive layer left after etching.
Etching is conducted under the conditions given below.
gas: SF 6 /N 2 =30/28 SCCM
pressure: 15 m Torr
applied electric power: 0.24 W/cm 2
The resist is patterned to form a resist pattern 6 which is then used to mask for etching, thereby forming a structure as shown in FIG. 8(e) in which is removed the layer 83 positioned widely on the aperture 1. A portion so removed is designated at 86 in FIG. 8(e). Etching removal of the W material may be done as by a wet etching system in which an H 2 SO 4 /H 2 O 2 solution is used or a plasma etching system in which a fluorine radical F + is used.
The masking margins of the resist are thus provided by refilling, leveling and etching as shown in FIGS. 8(b) to 8(d). A wiring 9 is made on the aperture 1 as viewed in FIG. 8(f). Voidless refilling of the aperture 2 is attained upon formation of the W layer by bias ECR-CVD. Refilling is stably done without the aperture 2 being scrapered since the deposition rate is set to be slightly greater than the etch rate at the shoulder of that aperture. Moreover, the electically conductive material is removed with utmost ease at a wider region on the substrate 1. This is due to the layer 83 being removable after etching of the material 85 substantially to the same level as the surface of the aperture 2. Mask matching is also possible with a sufficient degree of margin.
The wiring 9 of FIG. 8(f) may be modified to have a thickness other than the l thickness shown in FIGS. 8(b) or 8(c). Upon refilling of the recess 80 with the resist, etch backing is conducted at a rate of 1:1 of resist to W to thereby etch the resist together with the W material of a thickness specified above, leaving a W material of the l thickness.
Although various minor changes and modifications might be proposed by those skilled in the art, it will be understood that I wish to include within the claims of the patent warranted hereon all such changes and modifications as reasonably come within my contribution to the art.
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Methods for the production of wiring structures are disclosed which are rendered suitable, particularly for use in semiconductors. An electrically conductive material of a selected class is refilled, in a specified manner and by the bias ECR-CVD system, into the connecting hole positioned on a substrate. This is conducive to voidless refilling of the connecting hole and also to thin lamination of the electrically conductive material on a wiring region.
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FIELD OF THE INVENTION
The present invention relates to sulfur emissions from a sulfate cellulose mill and especially to a method of decreasing the emissions by heating the black liquor during the evaporation stage at a temperature higher than the cooking temperature, flash evaporating the black liquor and separating the sulfur containing gas therefrom.
BACKGROUND OF THE INVENTION
Wood is treated in sulfate cooking process by white liquor containing NaOH and Na 2 S, whereby lignin dissolves and cellulose fibers are released. The mixture of cellulose fibers (pulp) and cooking chemicals is then treated with water, resulting in the generation of black liquor. The black liquor is next concentrated by evaporation in an evaporation plant. The black liquor thereby concentrated is combusted in a soda recovery boiler, and the chemical melt thereby produced and containing mainly Na 2 S and Na 2 CO 3 , is dissolved in water, resulting in the generation of green liquor. The green liquor is next causticized by caustic lime (CaO) to white liquor containing NaOH, and lime sludge mainly comprising CaCO 3 . This white liquor is transferred back to the digester, and the lime sludge is calcinated in a lime sludge reburning kiln to caustic lime which is recycled back into the causticizing stage.
In a sulfate cellulose mill sulfur emissions are generated mainly in the soda recovery boiler, the evaporation plant and the digester house. In order to decrease the environmental impact of the cellulose mill the sulfur emissions should be minimized. It has been found that an increase in the dry solids content of black liquor causes a decrease in the sulfur emissions of the soda recovery boiler. On the other hand, the sulfur content of green liquor increases as a consequence thereof and thus also results in an increase in the sulfidity of the white liquor as well as the sulfur content of the black liquor. As a result, the overall sulfur emissions of an evaporation plant will increase as a consequence of the continuous increase of sulfur in the black liquor as described above. The instant invention is directed to overcoming this problem by removing the sulfur containing gas during the evaporation process but prior to the last stage thereof.
Finnish published application 75615 (U.S. Pat. No. 4,929,307) shows that the viscosity of the black liquor can be decreased by heating the liquor to a temperature higher than its cooking temperature. Consequently, it is possible to evaporate the black liquor to a higher dry solids content, while also decreasing the sulfur emissions of the soda recovery boiler. Also U.S. Pat. No. 2,711,430 discloses that heating of black liquor causes the release of organic sulfur compounds.
Surprisingly, it has been discovered that the above mentioned phenomena can be utilized in a completely new manner. It is thus an object of the instant invention to utilize the above-mentioned phenomena to control the sulfidity of a sulfate cellulose mill.
SUMMARY OF THE INVENTION
The foregoing object and other objects of the instant invention are achieved by the removal of sulfur from the black liquor in the form of a gas that contains sulfur compounds, by heat treating the black liquor in a pressure/heat reaction vessel prior to the last stage or effect of the evaporation at a temperature greater than the cooking temperature, and by adjusting the sulfidity of the white liquor by adjusting the temperature of the heat treatment and/or the retention time of the black liquor in the reaction vessel during the heat treatment.
When sulfur is removed from the black liquor before it is combusted in the soda recovery boiler, the sulfur content of the melt decreases and consequently also that of the green liquor and white liquor. Also the total emission level of sulfur from the pulp mill decreases, due to the decrease in sulfidity of the white liquor which is used in the digester to cook the wood chips and which is thereby converted into black liquor.
In the heat treatment of black liquor, generally about 1-3 weight-% of the dry solids contained therein will be released as a gas containing dimethylsulfide (DMS). By separating the gas from the black liquor before the liquor is supplied to the soda recovery boiler, the volume of dry solids flowing into the boiler decreases, and thus the load on the boiler decreases.
Moreover, we have found that by adjusting the temperature of the heat treatment and/or the retention time of the black liquor in the reaction vessel it is possible to control the amount of sulfur exiting from the black liquor and thus also adjust the sulfur content of the white liquor regenerated therefrom to a desired level.
In accordance with the instant invention, the heat treatment occurs preferably immediately prior to the final evaporation stage or effect by pressure heating the black liquor at a temperature of approximately 170°-200° C., preferably higher than 190° C. The treatment time depends on the temperature and the quality of the black liquor. The retention time is typically about 20 minutes in order to generate a gas that contains a significant amount of sulfur compounds.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be described further, by way of example, with reference to the accompanying drawings, in which:
FIG. 1 is a schematic diagram of a multistage flash evaporator and heater system for practicing the method in accordance with the present invention; and
FIG. 2 is a schematic illustration of an apparatus for separating the sulfur compounds containing fractions from the sulfur containing gas flow.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
In FIG. 1, an exemplary multiple effect evaporator system is shown comprising six evaporation stages or effects E I through E VI. The weak black liquor from the washing section having a dry solids content of about 18% is supplied to effect E VI through line or conduit 2. The six evaporators are of a conventional type, such as falling film evaporators in accordance with U.S. Pat. No. 3,366,158, where the liquor is caused to flow as a continuous film downwardly along the heat surfaces and is heated by hot vapor such as steam or vapor from any other source. Preferably the vapor generated by evaporation in effect E V is passed to effect E VI through line 4 and is utilized in effect E VI as the heating vapor. The evaporated liquor from effect E VI is transferred to the next effect E V through line 6, which has a higher temperature and pressure compared with the previous effect. Likewise, the liquor is transferred from effect EV to effect E IV through line 8 and from effect E IV to effect E III through line 10. The vapors from effect E III are passed to effect E IV through line 12 and from effect E IV to E V through line 14.
As a result of the evaporation, the dry solids content of the black liquor is increased in the example shown in FIG. 1 to a value of 37%. This somewhat concentrated black liquor is then transferred through line 16 for further concentration to a multistage flash evaporator and heater system comprising heat exchangers HEX I through HEX VII, flash tanks FT I through FT VI and reactor vessel 18. The heat exchangers and flash tanks are operatively connected together in the manner such that black liquor flows through the flash tanks countercurrently relative to the black liquor flow through the heat exchangers and the vapor generated in the expansion of the liquor is used to indirectly heat the liquor in the heat exchangers. Thus, the heat exchangers are connected in series through lines 20, 22, 24, 26, 28 and 30. The flash tanks are operatively connected in series through lines 36, 38, 40, 42 and 44. The flash tanks are operatively connected to the heat exchangers through lines 46, 48, 50, 52, 54 and 56. The black liquor coming from the evaporation plant is pumped to heat exchanger HEX I through line 16. In HEX I, this liquor is heated by the vapor coming from flash tank FT I through line 46. Similarly, the liquor is heated in heat exchangers HEX II through HEX VI with vapor from flash tanks FT II through FT VI. The liquor is heated with fresh vapor or steam through line 68 in the last heat exchanger HEX VII, whereafter it is transferred for the above described pressure heating to reactor vessel 18 through line 32. From the reactor vessel 18, the liquor is transferred to flash tank FT VI through line 34. The liquor expands step by step from the pressure of about 13 bar to the pressure of about 2 bar in the flash tanks connected in series and the temperature thereof decreases. The liquor from the last flash tank FT I is pumped through line 70 to effect E II of the evaporation plant and further through line 72 to effect E I. Effect E I is heated by fresh vapor or steam through line 78. The vapor from the evaporation of effect E I is transferred through line 74 to effect E II and the vapor from effect E II is transferred in a corresponding manner through line 76 to effect E III.
The objectives of the pressure heating step described herein, are, on the one hand, to decrease the viscosity of the black liquor to be concentrated in the final evaporation stage thereby facilitating and improving the evaporation and further treatment of the liquor, and, on the other hand, to remove the sulfur therefrom. These objectives are achieved by increasing the temperature of the black liquor in the system shown in FIG. 1 by sequentially heating the liquor in the heat exchangers HEX I-HEX VII step by step from about 90° C. to about 191° C., and by maintaining the liquor at said temperature in the reactor 18 for about 20 minutes. As a consequence of this procedure, lignin molecules in the black liquor are split which results in the aforementioned decrease of viscosity. The decreased viscosity facilitates the final concentration of the liquor at effect E I of the evaporation plant to a dry solids content of about 80%. At the same time, the methoxy groups of the lignin are removed, and DMS is generated.
The black liquor can be maintained at 170° C. between 5 and 60 minutes or preferably between 10 and 30 minutes. Alternatively, the black liquor can be maintained at 190° C. between 5 and 60 minutes or preferably between 10 and 30 minutes.
When the expansion vapor of the liquor exiting from the flash tanks is condensed in heat exchangers HEX I-HEX VI, a secondary condensate is generated therein. This condensate is transferred through constriction plates from a heat exchanger operating at a higher pressure to a heat exchanger operating at a lower pressure through lines 58, 60, 62, 64 and 66. When the condensate reaches the heat exchanger operating at a lower pressure it expands generating non-condensable gas and also releasing heat to the liquor flowing in the heat exchangers counter current to the flow of the secondary condensate. The non-condensable gases containing the sulfur compounds are discharged from the heat exchangers and transferred to a common gas discharge line 80, which is then connected to a sulfur recovery or elimination apparatus as that shown in FIG. 2.
FIG. 2 schematically illustrates an apparatus in which the sulfur compounds containing gas that has been withdrawn from the black liquor in the described pressure-heating process including the flashing and expansion step is divided into two fractions of which one contains all or substantially all of the sulfur compounds and the other is substantially sulfur-free.
Sulfur containing gases produced in the system shown in FIG. 1 are channeled through conduit 80 and transferred to a conventional two-zone packed tower 84. In tower 84 these gases pass between the zones. Vapor or steam is supplied through conduit 86 to the bottom part of tower 84.
As shown in FIG. 2, sulfurous gas exiting from tower 84 is cooled in cooler 88, and two fractions, one composed of substantially sulfur-free condensate containing methanol and another comprising gas containing the majority or all of the sulfur compounds, are generated. A portion of the condensate from cooler 88 is supplied by a conduit 90 to the upper part of tower 84. The remaining portion of the condensate is supplied by a conduit 90 to combustor 100, where it is combusted, and heat is recovered in the heat recovery apparatus 102. The fraction comprising the gas which contains most of the sulfur compounds passes out of cooler 88 through conduit 92 into combustor 94, where it is combusted. Heat generated in this combustion is recovered in heat recovery apparatus 96, and the generated SO 2 is absorbed in either water, NaOH-solution or white liquor in absorption apparatus 98, or the SO 2 is condensed.
Sulfurous gases that are generated in other parts of the pulp mill such as the cooker, evaporation plant and stripping columns, can be combined with the gas generated in the pressure heating stages shown in FIG. 1, and supplied into packed tower 84, through conduit 80.
It is also apparent that the sulfur compounds in the gas flow in pipe 80 can be recovered or separated by using other known methods, without deviating from the scope of the instant invention.
While there have been shown, described and pointed out the fundamental novel features of the invention as applied to preferred embodiments thereof, it will be understood that various omissions, substitutions and changes in the form and details illustrated and in the operation of the process may be made by those skilled in the art without departing from the spirit of the invention. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.
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To decrease the sulfur emissions of a sulfate cellulose mill, black liquor is heated before the last effect of the evaporation at a temperature higher than the cooking temperature of the sulfate cook and the sulfidity of white liquor is adjusted by adjusting the temperature and/or retention time of the heat treatment so that a predetermined amount of sulfur compounds are separated from the gaseous black liquor. Preferably, the sulfur containing gas is thereafter divided into different fractions and separately combusted.
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RELATED APPLICATION
[0001] This application is a continuation-in-part of PCT Application Serial No. PCT/AU03/001224, filed Sep. 18, 2003.
FIELD OF THE INVENTION
[0002] This invention relates to a treatment laser instrument designed for use by ophthalmologists for performing selective laser trabeculoplasty (for treating glaucoma) procedures and secondary cataract surgery procedures. In particular, the invention relates to an ophthalmic laser system that can operate effectively in both the infrared region (for secondary cataract treatment) and other regions, such as the green region (for glaucoma treatment).
BACKGROUND TO THE INVENTION
[0003] Glaucoma (abnormal intra-ocular pressure) is a major eye problem that leads to blindness in a significant percentage of the world population. Glaucoma is the most common cause of blindness in the world today. The established technique for treating glaucoma is drug based. Alternative treatment modalities have been sought to avoid the side effects and non-specificity associated with drug based treatments. Over the past few years a technique known as selective laser trabeculoplasty (SLT) has been invented by Latina. The technique is described in U.S. Pat. No. 5,549,596, assigned to The General Hospital Corporation. Latina describes the use of a frequency doubled Nd:YAG laser for the SLT procedure.
[0004] SLT is an improvement over a previously used technique referred to as argon laser trabeculoplasty (ALT). ALT uses a thermal effect to coagulate loose trabecular meshwork cells believed to be present in patients with glaucoma. Because an Argon laser is essentially CW (if pulsed, the pulse duration is long compared to thermal transfer mechanisms) there is significant heat transfer into surrounding tissue. This results in damage to otherwise healthy cells. It has been found that the ALT process can only be used once or twice before collateral damage prevents any further benefit from ALT treatment.
[0005] In contrast, SLT utilizes a pulsed laser (the pulse duration is short compared to thermal effects) so there is minimal heat transfer to surrounding tissue. SLT has been found to be repeatable, unlike the ALT process.
[0006] A detailed discussion of the SLT modality and a comparison with ALT is found in Ocular Surgery News published 1 Mar. 2000.
[0007] Another very common ophthalmic treatment is secondary cataract surgery. The most effective laser for secondary cataract surgery is a Nd:YAG laser operating at 1064 nm. These lasers are typically referred to as photodisruptors as they act by non-thermal mechanisms to cut tissue. A typical ophthalmic laser system consists of the laser head and a beam delivery system coupled to a conventional slit lamp assembly. A typical laser system for secondary cataract surgery is described in U.S. Pat. No. 6,325,792.
[0008] At present, two separate laser systems are necessary to perform the procedures for treating the two most common eye problems.
[0009] An attempt to address the problem of requiring multiple lasers for different treatment modalities has been described in U.S. Pat. No. 6,066,127. This patent describes a system for changing the laser cavity between a pulsed configuration and a continuous wave configuration by introducing a movable intracavity element. This approach is problematic because it is extremely difficult to maintain optimum alignment of the laser cavity with a movable intracavity element.
[0010] A better solution is required.
SUMMARY OF THE INVENTION
[0011] In one form, although it need not be the only or indeed the broadest form, the invention resides in an ophthalmic laser system comprising a laser module producing a beam of short pulses of radiation with high energy density at a first wavelength; a first beam path incorporating an attenuator, beam shaping optics, and means for directing the beam at said first wavelength to an eye of a patient; a second beam path incorporating a frequency conversion module that converts the beam at the first wavelength to a beam at a second wavelength, an attenuator, and means for directing the beam at said second wavelength to the eye of the patient; and extracavity deflecting means for selectively deflecting the beam at said first wavelength into the second beam path, said means being operable between a first position in which the beam at said first wavelength follows the first beam path and a second position in which the beam at said first wavelength is deflected to said second beam path.
[0012] Preferably the beam at said first wavelength is a 1064 nm beam produced by a Nd:YAG laser, and said beam at said second wavelength is frequency-doubled to 532 nm. The beam is suitably doubled by a KTP doubling crystal or similar frequency doubling device.
[0013] Preferably the extracavity deflecting means comprises a half wave plate and polarizer. The half wave plate is suitably remotely operable, such as by a servo motor or solenoid.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] To assist in understanding the invention, preferred embodiments will be described with reference to the following figures in which:
[0015] [0015]FIG. 1 shows a general schematic view of an ophthalmic laser system;
[0016] [0016]FIG. 2 shows a schematic side view of the photodisruptor optical system of the ophthalmic laser system in FIG. 1; and
[0017] [0017]FIG. 3 shows a schematic view of the SLT optical system of the ophthalmic laser system in FIG. 1;
[0018] [0018]FIG. 4 shows a schematic view of the energy monitor system;
[0019] [0019]FIG. 5 shows a schematic of the beam-shaping module of the photodisruptor optical system;
[0020] [0020]FIG. 6 shows a schematic of the beam-shaping module of the SLT optical system; and
[0021] [0021]FIG. 7 shows an external view of an ophthalmic treatment device incorporating the ophthalmic laser system.
DETAILED DESCRIPTION OF THE INVENTION
[0022] Referring to FIG. 1, there is shown an embodiment of an ophthalmic laser system 1 useful for treating glaucoma and secondary cataracts. The system is comprised of a laser module 2 , a photodisruptor optical system 3 and SLT optical system 4 , as shown separately in FIGS. 2 and 3.
[0023] The ophthalmic laser system 1 of the present invention combines the photodisruptor optical system 3 and SLT optical system 4 into one integral unit, which uses a single laser module 2 . The laser module 2 is a Q switched Nd:YAG laser operating in the infrared spectrum. The laser emits a beam at 1064 nm wavelength, having a pulse width of less than 5 nsec. Other laser modules (such as Nd:YLF, Yb:YAG, etc) will also be suitable as will be readily apparent to persons skilled in the art.
[0024] Referring now to FIG. 1 and FIG. 2, a pulsed beam from the laser module 2 is attenuated at attenuator/beam steering module 5 . An energy monitor system 6 measures the energy in each pulse. For the photodisruptor optical system the desired energy density is 0.3-10 mj in an 8-10 μm spot. A half wave plate 7 within the attenuator/beam steering module 5 is adjusted to regulate the intensity of the pulsed beam in the photodisruptor optical system 3 . A polarizing plate 8 may deflect the pulsed beam to the SLT optical system 4 depending on the orientation of the half wave plate 7 . The function of the attenuator/beam steering module 5 will be described in more detail later.
[0025] Beam shaping optical module 9 expands the pulsed beam before it travels up to the folding mirror module 10 . The expanded beam is then focused by objective lens 13 to produce the 8-10 μm beam waist at the treatment site which is required to produce photodisruption. An aiming laser module 11 provides a continuous, visible laser beam that is split into two beams and deflected by folding mirror module 10 to give a targeting reference for the treatment beam. These two aiming laser beams converge with the pulsed treatment beam at the target site in a patient's eye 12 via objective lens 13 . An operator 14 views the patient's eye 12 through the folding mirror module 10 . A safety filter 15 protects the eye of the operator. The folding mirrors 10 a, 10 b are positioned so that the viewing axis of the operator is not impeded. It will be appreciated by those skilled in the art that the mirrors may be replaced by prisms or other suitable beam steering optics.
[0026] Referring to FIG. 3, the SLT optical system 4 comprises a mirror 16 that directs a deflected pulsed beam from the polarizing plate 8 in the attenuator/beam steering module 5 of FIG. 1 to the frequency conversion module, which is a frequency doubling module 17 in the preferred embodiment. To maximize frequency doubling efficiency the entire pulsed beam is deflected by attenuator/beamsteering module 5 . The frequency doubling module 17 converts the output of the laser module to half the wavelength so that the output of the SLT optical system is in the visible spectrum. For the particular embodiment the Nd:YAG laser module operates in the near infrared at 1064 nm which is frequency doubled to 532 nm, which is in the green region of the visible spectrum. The green pulsed beam is effective in treating glaucoma in patients.
[0027] The pulsed green beam may be attenuated at the SLT attenuator 18 to regulate the energy in the pulsed green beam. An energy monitor system 19 measures the energy in each pulse. For the SLT process the desired energy density is 0.01-5 J/cm 2 , as described by Latina.
[0028] Other wavelengths may be suitable for other ophthalmic applications in which case the frequency conversion module may triple or quadruple the fundamental frequency. In some applications it may even be desirable to use a tunable frequency conversion module, such as an optical parametric oscillator.
[0029] A beam shaping module 20 adjusts the beam profile to provide an even energy distribution at the treatment plane. The green beam then travels to a second folding mirror module 21 . A second aiming laser module 22 provides a single aiming laser beam which is deflected by the second folding mirror 21 and transmitted through folding mirror module 10 and objective lens 13 , as shown in FIG. 1. The continuous visible laser aiming beam generated by the second aiming laser module 22 coincides with the green pulsed beam at the target site in a patient's eye 12 via objective lens 13 and contact lens 23 . As mentioned earlier, the mirror could be replaced by prisms or other suitable optical elements.
[0030] Although two separate aiming laser modules 11 , 22 are described, it will be appreciated that a single aiming laser module could be used with appropriate beam deflecting optics, such as a mirror, to direct the aiming laser beam through folding mirror module 10 for off-axis illumination or folding mirror module 21 for on-axis illumination.
[0031] The present invention provides an ophthalmic laser system for treating glaucoma and secondary cataract conditions, using a single laser source. The present invention integrates two known laser treatment techniques, SLT and photodisruptor, into one integrated system.
[0032] The method used to direct the laser beam from the laser module 2 to the photodisruptor optical system 3 or the SLT optical system 4 will now be described in detail. Referring to FIG. 1, the attenuator/beam steering module 5 first receives a pulsed and linearly polarized beam from laser module 2 at half wave plate 7 . The pulsed beam passes through the half wave plate to the polarizing plate 8 .
[0033] The orientation of the half wave plate 7 determines the amount of the pulsed beam that is passed through the polarizing plate 8 into the photodisruptor optical system 3 . The orientation of the half wave plate 7 can be adjusted by motorized means so that the polarization angle of the component of the resulting beam which coincides with the transmission characteristic of the polarizing plate 8 will be passed through to the beam shaping module 9 . However, as the half wave plate 7 is rotated, the polarization of the beam is changed. Accordingly, only some portion of the beam will be transmitted.
[0034] In the photodisruptor mode for treating secondary cataracts, the half wave plate 7 is rotated to permit transmission of the required pulsed laser beam emitted from the laser module 2 . If the SLT mode is required, the half wave plate 7 is oriented so that all the beam is reflected from the polarising plate 8 to the mirror 16 of the SLT optical system 4 .
[0035] The ophthalmic laser system described above allows an operator to select the mode of treatment to be administered to a patient, simply by choosing one of two optical paths. A simple adjustment of the half wave plate 7 determines whether a SLT or a photodisruptor mode is chosen for treating glaucoma or secondary cataracts respectively. The adjustment of the half wave plate can be motorized so the selection of treatment modality may be by simple button selection.
[0036] It will be appreciated that the directing of the Nd:YAG laser beam into the photodisruptor module path or the SLT module path can be achieved by any suitable means (such as a mirror) but the use of a polarizing plate is preferred.
[0037] As mentioned above, each optical system includes an energy monitor system in the preferred embodiment. A schematic of the components of an energy monitor system is shown in FIG. 4. A small percentage of the beam is split by optic plate 24 towards a photodiode 25 . A number of filters and diffusers 26 are positioned in front of the photodiode 25 .
[0038] As seen in FIG. 2, once the pulse beam is attenuated to the desired power, the beam is further conditioned by beam shaping optical module 9 . The beam shaping optical module 9 is shown in more detail in FIG. 5. Lenses 27 and 28 form a beam expander which expands the 3 mm diameter beam from the laser module 2 by ten times. The expanded beam is reflected into the optical viewing path by the folding mirror 10 which uses a wavelength selective coating to avoid blocking of the viewing path. The beam from folding mirror 10 is then focused by objective lens 13 to produce the 8-10 μm beam waist at the treatment site which is required to produce photodisruption.
[0039] Referring to FIG. 6, the SLT beam is conditioned by beam shaping module 20 before the folding mirror module 21 . The beam shaping module 20 consists of two lenses 28 , 29 that form a beam expander that is designed to produce a well defined treatment spot with an even energy distribution.
[0040] The invention is conveniently embodied in an ophthalmic treatment device of the type shown in FIG. 7. The treatment device 30 is of the conventional form having a slit lamp assembly 31 mounted on a table 32 which is in turn mounted on a height adjusting pedestal 33 . The slit lamp assembly 31 is movable with respect to the table 32 using joystick 34 , in conventional manner. The ophthalmic laser system is mounted in the body 35 of the slit lamp assembly 31 . This is achieved by using a compact laser cavity and careful placement of optical components.
[0041] The ophthalmic laser system is controlled by a control panel 36 . The joy stick 34 may incorporate a fire button 37 to fire the laser, or alternatively a foot pedal (not shown) may be used.
[0042] The invention has been described with reference to one particular embodiment however, it should be noted that other embodiments are envisaged within the spirit and scope of the invention. For instance, one or two aiming lasers could be used, the photodisruptor or SLT beam path could be selected by a movable mirror, or the beam shaping optics could have a different configuration.
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An ophthalmic laser system generating a first beam at a wavelength suitable for performing selective laser trabeculoplasty and selectively generating a second beam at a wavelength suitable for performing secondary cataract surgery procedures. The laser system is able to select between directing the first beam or the second beam to the eye of a patient. The first beam is suitably generated at 1064 nm from a Nd:YAG laser and the second beam is frequency doubled to 532 nm in a KTP doubling crystal.
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PRIORITY
[0001] This application claims a priority from U.S. Provisional Application 60/197,179 filed Apr. 14, 2000.
FIELD OF THE INVENTION
[0002] This invention provides new compounds that are useful as insecticides and acaricides, new synthetic procedures and intermediates for preparing the compounds, pesticide compositions containing the compounds, and methods of controlling insects and mites using the compounds.
BACKGROUND OF THE INVENTION
[0003] There is an acute need for new insecticides and acaricides. Insects and mites are developing resistance to the insecticides and acaricides in current use. At least 400 species of arthropods are resistant to one or more insecticides. The development of resistance to some of the older insecticides, such as DDT, the carbamates, and the organophosphates, is well known. But resistance has even developed to some of the newer pyrethroid insecticides and acaricides. Therefore a need exists for new insecticides and acaricides, and particularly for compounds that have new or atypical modes of action.
[0004] A number of 3,5-diphenyl-1H-1,2,4-triazole derivatives have been described in the literature as having acaricidal activity (U.S. Pat. No. 5,482,951; JP 8092224, EP572142, JP 08283261). Nitro furanyl triazoles are described by L. E. Benjamin and H. R. Snyder as antimicrobials ( J Heterocyclic Chem. 1976, 13, 1115) and by others as antibacterials ( J Med. Chem. 1973, 16(4), 312; J Med. Chem. 1974, 17(7), 756). The present invention provides novel compounds with broad spectrum activity against mites and insects.
SUMMARY OF THE INVENTION
[0005] This invention provides novel compounds especially useful for the control of insects and mites.
[0006] More specifically, the invention provides novel insecticidally active compounds of the formula (1)
[0007] wherein
[0008] Ar is phenyl, substituted phenyl, pyridyl, substituted pyridyl, or lower alkyl;
[0009] R 1 is lower alkyl, cycloalkyl, phenyl, or substituted phenyl;
[0010] Q is thienyl, substituted thienyl, phenyl, substituted phenyl, pyridyl, or substituted pyridyl;
[0011] R 2 is selected from H, lower alkyl, lower alkenyl, pyridyl, substituted pyridyl, pyrimidyl, substituted pyrimidyl, isoxazolyl, substituted isoxazolyl, naphthyl, substituted naphthyl, phenyl, substituted phenyl, thienyl, substituted thienyl, —(CH 2 ) m R 3 , —CH═CHR 3 , —C≡CR 3 , —CH 2 OR 3 , —CH 2 SR 3 , —CH 2 NR 3 R 3 , —OCH 2 R 3 , —SCH 2 R 3 ,—
[0012] R 3 is H, lower alkyl, haloalkyl, lower alkenyl, lower alkynyl, phenyl, or substituted phenyl;
[0013] m is 1 or2;
[0014] n is an integer from 2 to 6; or a phytologically acceptable acid addition salt thereof.
[0015] Preferred compounds of formula (1) include the following classes:
[0016] (1) Compounds of formula (1) wherein Ar is a group of the formula
[0017] wherein R 4 and R 5 are independently H, Cl, F, methyl, halomethyl, methoxy, or halomethoxy.
[0018] (2) Compounds of formula (1) wherein Ar is a group of the formula
[0019] wherein R 4 and R 5 are independently H, Cl, F, methyl, halomethyl, methoxy, or halomethoxy.
[0020] (3) Compounds of class (1) and (2) wherein R 4 and R 5 are independently F or Cl.
[0021] (4) Compounds of class (1) and (2) wherein R 4 and R 5 are both F.
[0022] (5) Compounds of class (1) and (2) wherein R 4 and R 5 are both Cl.
[0023] (6) Compounds of class (1) and (2) wherein R 4 is F and R 5 is Cl.
[0024] (7) Compounds of formula (1), and particularly compounds of class (1), (2), (3), (4), (5) or (6) as defined above, wherein Q is a substituted thiophene.
[0025] (8) Compounds of formula (1), and particularly compounds of class (1), (2), (3), (4), (5) or (6) as defined above, wherein Q is a substituted phenyl.
[0026] (9) Compounds of formula (1), and particularly compounds of any one of classes (1) through (8) as defined above, wherein R 2 is methyl.
[0027] (10) Compounds of formula (1), and particularly compounds of any one of classes (1) through (9) as defined above, wherein R 2 is a phenyl or substituted phenyl.
[0028] (11) Compounds of formula (1), and particularly compounds of any one of classes (1) through (9) as defined above, wherein R 2 is a thiophene or substituted thiophene.
[0029] The invention also provides new processes and intermediates for preparing compounds of formula (1) as well as new compositions and methods of use, which will be described in detail hereinafter.
DETAILED DESCRIPTION OF THE INVENTION
[0030] Throughout this document, all temperatures are given in degrees Celsius, and all percentages are weight percentages unless otherwise stated.
[0031] The term “lower alkyl” refers to (C 1 -C 6 ) straight hydrocarbon chains and (C 3 -C 6 ) branched and cyclic hydrocarbon groups.
[0032] The terms “lower alkenyl” and “lower alkynyl” refer to (C 2 -C 6 ) straight hydrocarbon chains and (C 3 -C 6 ) branched hydrocarbon groups containing at least one double or triple bond, respectively.
[0033] The term “lower alkoxy” refers to —O—lower alkyl.
[0034] The terms “halomethyl”, “haloalkyl”, and “haloalkenyl” refer to methyl, lower alkyl, and lower alkenyl groups substituted with one or more halo atoms.
[0035] The terms “halomethoxy” and “haloalkoxy” refer to methoxy and lower alkoxy groups substituted with one or more halo atoms.
[0036] The term “alkoxyalkyl” refers to a lower alkyl group substituted with a lower alkoxy group.
[0037] The term “alkoxyalkoxy” refers to a lower alkoxy group substituted with a lower alkoxy group.
[0038] The terms “substituted naphthyl”, “substituted thienyl,” “substituted pyrimidyl,” “substituted pyrazolyl,” “substituted pyridyl,” and “substituted isoxazolyl” refer to the ring system substituted with one or more groups independently selected from halo, halo (C 1 -C 4 ) alkyl, CN, NO 2 , (C 1 -C 4 ) alkyl, (C 3 -C 4 ) branched alkyl, phenyl, (C 1 -C 4 ) alkoxy, or halo (C 1 -C 4 ) alkoxy.
[0039] The term “substituted phenyl” refers to a phenyl group substituted with one or more groups independently selected from halo, (C 1 -C 10 ) alkyl, branched (C 3 -C 6 ) alkyl, halo (C 1 -C 7 ) alkyl, hydroxy (C 1 -C 7 ) alkyl, (C 1 -C 7 ) alkoxy, halo (C 1 -C 7 ) alkoxy, phenoxy, phenyl, NO 2 , OH, CN, (C 1 -C 4 ) alkanoyl, benzoyl, (C 1 -C 4 ) alkanoyloxy, (C 1 -C 4 ) alkoxycarbonyl, phenoxycarbonyl, or benzoyloxy.
[0040] Unless otherwise indicated, when it is stated that a group may be substituted with one or more substituents selected from an identified class, it is intended that the substituents may be independently selected from the class.
[0041] Synthesis
[0042] Compounds of formula (1) can be prepared by the methods illustrated in Scheme 1:
[0043] wherein Ar is phenyl or substituted phenyl, Q, and R 2 are defined as in formula (1) above. The sequence shown in Scheme 1 involves the coupling of acid chlorides of formula (2) with the amidrazone of formula (3). Preparation 1, hereinafter, illustrates preparation of an amidrazone of formula (3). The base used in the coupling could be any organic or inorganic base. Acid chlorides of formula (2) are prepared from corresponding carboxylic acids of formula (11)
[0044] which are either commercially available or are readily made through known procedures. Examples 1 and 2, hereinafter, illustrate the coupling and cyclization utilizing the amidrazone of formula (3) to produce a triazole product of formula (1).
[0045] Preparation 1
[0046] The following steps illustrate preparation of the amidrazone of formula (3a)
[0047] A. 2,6-difluorobenzenethioamide
[0048] Into a 3 L three necked round bottom flask equipped with a mechanical stirrer, dry ice condenser, dropping funnel, and outlet to a trap filled with bleach was added pyridine (550 mL), 2,6-difluorobenzonitrile (208 g, 1.50 mol), triethylamine (202 g, 279 mL, 2.0 mol), and sodium sulfide hydrate (521 g, 2.17 mol-broken into pieces small enough to fit into the flask). The temperature of the stirred mixture was lowered to approximately 5° C. and to the slurry was added dropwise concentrated hydrochloric acid (143 g, 288 mL, 3.99 mol). An exotherm was noted and the rate of addition of the hydrochloric acid was such that the temperature of the reaction mixture did not exceed 25° C. for a total addition time of 75 min. The cooling bath was removed and the slurry was allowed to warm to RT and to stir over night. The mixture was poured into water (2 L) and was extracted with ether (3×500 mL). The ether layer was washed with dilute sulfuric acid, water, brine, dried (MgSO 4 ), and the solvent removed in vacuo to give 232 grams of crude product. The starting material was removed from the product via kugelrohr distillation to give 197 g (76%) of 2,6-difluorobenzenethioamide. This material was used without further purification.
[0049] B. S-methylthio-2,6-difluorobenzamidinium iodide
[0050] Into a 3 L three necked flask equipped with a mechanical stirrer and dropping funnel was added acetone (1150 mL) and 2,6-difluorobenzenethioamide (197 g, 1.14 mol). The temperature of the stirred solution was lowered to approximately 5° C. and iodomethane (161 g, 70.6 mL, 1.14 mol) was added dropwise. The ice bath was removed and the slurry was allowed to stir over night. The resulting yellow solids were removed via filtration and washed with ether to obtain 223 grams. An additional portion of material was obtained from the filtrate by removal of the solvent in vacuo. Ether was added to the residue and the resulting solids removed via filtration to obtain an additional 57 grams of material. The combined solids totaled 280 g (77.9% yield) of S-methylthio-2,6-difluoro-benzimidinium iodide: mp 168-169° C.; 1 H NMR (DMSO-d 6 ) δ7.7 (m, 1H), 7.4 (m, 2H), 2.7 (s, 3H).
[0051] C. N-tert-butoxvcarbonyl-N-methylhydrazine
[0052] Into a 1 L three necked round bottom flask equipped with a mechanical stirrer and dropping funnel was added methyl hydrazine (42.2 g, 0.916 mol) and THF (100 mL). The temperature of the mixture was cooled to 5° C. and a solution of di-tert-butyl dicarbonate (100 g, 0.458 mol) dissolved in THF (150 mL) was added dropwise. The cooling bath was removed and the mixture was stirred at RT overnight. The liquid was decanted from a gummy precipitate and the solvent removed in vacuo to give approximately 70 grams of a clear liquid. The gummy precipitate was partitioned between methylene chloride and water. The methylene chloride was washed with brine, dried (Na 2 SO 4 ) and the solvent removed in vacuo. The resulting residue was combined with that from the previous evaporation and distilled at approximately 20 mm Hg (bp 77-78° C.) to give 40.2 g (60% yield) of N-tert-butoxycarbonyl-N-methylhydrazine: 1 H NMR (CDC13) 6 4.1 (bs, 2H), 3.05 (s, 3H), 1.5 (s, 9H).
[0053] D. Amidrazone of formula (3a)
[0054] Into a 1 L round bottom flask equipped with a mechanical stirrer, dropping funnel, and outlet to a trap filled with bleach, was added S-methyl-2,6-difluorobenziminium iodide (63.8 g, 0.202 mol) and methanol (180 mL). To the stirred solution was added dropwise N-tert-butoxycarbonyl-N-methylhydrazine (29.6 g. 0.202 mol). The solution was allowed to stir overnight and the methanol was removed in vacuo. The residue was triturated with ether and the solids removed via filtration to give 66.3 grams (79.0% yield) of the amidrazone of formula (3a): mp 172-173° C. (dec); 1 H NMR (DMSO-d 6 ) δ12.3 (s, b, 1H), 10.4 (d, b, 2H), 7.9 (m, 1H), 7.4 (m, 2H), 3.1 (s, 3H), 1.5 (s, 9H).
EXAMPLE 1
[0055] [0055]
[0056] A mixture of the t-Boc protected amidrazone (3a) (0.86 g, 3.0 mmol), the 6-Phenylethynylnicotinic acid (0.67 g, 3.0 mmol) and dicyclohexylcarbodiimide (0.62 g, 3.0 mmol) in 10 mL of CH 2 Cl 2 was treated with a catalytic amount of 4-N,N-dimethylaminopyridine. The resultant mixture was allowed to stir at room temperature, under N 2 . After 40 hours the reaction mixture was filtered through a plug of Celite, washing with CH 2 Cl 2 . The filtrate was concentrated in vacuo to give 1.75 g of a yellow oil. This was chromatographed on silica gel (MPLC), eluting with 65% hexanes/35% ethyl acetate. Isolation of the major product gave 0.54 g (37% yield) of the desired product as a yellow oil: 1 H NMR (CDCl 3 ) δ10.2 (br, 1H), 9.09 (dd, 1H, J =0.6, 1.8 Hz), 8.14 (dd, 11H, J =2.4, 8.3 Hz), 7.63-7.60 (m, 3H), 7.40-7.38 (m, 4H), 6.98-6.93 (m, 2H), 3.29 (s, 3H), 1.49 (s, 9H).
EXAMPLE 2
[0057] 1-Methyl-3-(2,6-difluorophenyl)-5-(6-ethynylphenyl-3-pyridinyl)-1,2,4-Triazole (1a)
[0058] A mixture of the t-Boc protected amidrazone (4a) and 5 mL of trifluoroacetic acid was allowed to stir at room temperature. After stirring for three days TLC analysis showed that all of the starting material had been consumed. The reaction mixture was poured into H 2 O (25 mL) and extracted with ethyl acetate (3×25 mL). The combined organic extracts were washed with H 2 O (2×25 mL), saturated NaCl (1×25 mL), dried (MgSO 4 ), filtered and concentrated to give 0.63 g of a dark yellow oil. This was chromatographed on silica gel (MPLC), eluting with 70% hexane/30% ethyl acetate. Isolation of the major product gave 0.208 g (56% yield) of the desired product as a light tan solid: mp 137-138° C.; 1 H NMR (CDCl 3 ) δ9.02 (dd, 1H, J=0.9, 2.6 Hz), 8.14 (dd, 1H, J=2.1, 8.4 Hz), 7.70 (dd, 1H, J=0.9, 8.1 Hz),7.65-7.62 (m, 2H), 7.42-7.37 (m, 4H), 7.06-7.00 (m, 2H), 5.15 (s, 3H).
[0059] Another route to intermediates of formula (5) is shown in Scheme 2, wherein Ar, Q, and R 1 are as defined in formula (1).
[0060] Aryl acyl(thio)imidates of type (12) are known in the literature and can be used as their acid addition salt. In this case, tetrafluoroboric acid, hydrogen chloride, hydrogen bromide, hydrogen iodide, or the like, may be used. Aryl acylimidates are available through the nitrile ( J Org. Chem. 1968, 33, 1679 and U.S. Pat. No. 4,025,504). Methyl thioimidate of formula (12) are prepared from corresponding arylnitriles of formula (14) where R 4 and R 5 are as defined in formula 1 above and X is carbon or nitrogen,
[0061] which are either commercially available or are readily made through known procedures as depicted in Scheme 3 and as illustrated hereinafter in Preparation 2. Thioimidates are readily available through alkylation of the corresponding thioamides which themselves are commercially available or can be made from the amide (Phosphorous Sulfur (1985), 25(3), 297-305) or nitrile ( Chem.-Ztg. 1980, 104, 365; J Chem. Soc. 1952, 742; Can. J Chem. 1985, 63, 3075). Reaction of the acid chloride of formula (2) and the imidate (12) to give adduct (13) can be accomplished in any inert solvent with any organic or inorganic base. Reaction of compounds such as (13) with alkyl or aryl substituted hydrazine gives the triazole intermediate (5) in good yield with a high degree of regiospecificity. Preparation 3, hereinafter, illustrate the preparation of a thioamide of formula (13) using the above described procedure. Preparations 4 and 5, hereinafter, illustrate the synthesis of a triazole of formula (5) using the procedure involving the addition of a substituted hydrazine to the thioamide of formula (13).
[0062] Preparation 2
[0063] The following steps illustrate preparation of S-methylthio-3,5-dichloro-4-pyridylimidinium iodide (12a)
[0064] A. 3,5-dichloro-4-pyridinethioamide (16a)
[0065] Into a 3000-mL three-necked round bottom flask equipped with a condenser, mechanical stirrer under an atmosphere of nitrogen was added pyridine (1500 mL), then 3,5-dichloro-4-pyridine-carboxamide (92.9 g, 0.486 mol) which dissolved, and tetraphosphorus decasulfide (237 g, 0.535 mol), which had almost dissolved then a bright yellow precipitate formed and an exotherm heated the mixture to 60° C. The slurry was allowed to stir for 1 h (temperature had dropped to 45° C.) and then the temperature was raised. At 100° C. all of the solids had dissolved and heating was continued to 118° C. and was maintained at 115° C. for 4 h. The mixture was poured into water (3750 mL) carefully as gas began to evolve and the temperature of the aqueous solution rose to approximately 45° C. and was allowed to sit at room temperature over two nights. To the resulting mixture was added water (6000 mL) and was extracted with methylene chloride (3×2000 mL), washed with water (3×1000 mL) and the solvent removed in vacuo to give a brownish yellow liquid, with much pyridine present. The vacuum pump was connected to the rotary evaporator to remove the residual pyridine. The residue (brown solid) was triturated with diethyl ether (3×1500 mL), treated with decolorizing carbon and the solvent removed in vacuo to give a solid which contained pyridine. The yellow solid was slurried in water (2×200 mL) and dried in vacuo at 60° C. to give 63.2 g of a light yellow solid (62.8% yield): mp 186-187° C.; TLC [50/50 ethyl acetate/hexanes] showed amide at Rf=0.31 and thioamide Rf=0.53; 1 H NMR (DMSO-d 6 ) δ10.6 (bs, 1H), 10.0 (bs, 1H), 8.6 (s, 2H).
[0066] The following step illustrates the preparation of the S-methyl imidate of formula (12a). Into a 3 L three necked flask equipped with a magnetic stirrer was added acetone (80 mL) and 3,5-dichloro-4-pyridylthioamide (15.87 g, 76.6 mmol). To the stirred solution iodomethane (10.89 g, 4.77 mL, 76.6 mmol) was added dropwise. The slurry was stirred over night. The resulting yellow solids were removed via filtration and washed with ether to obtain 15.23 grams (57%) of S-methylthio-3,5-dichloro-4-pyridylimidinium iodide: mp 158-161° C. 1 H NMR (DMSO-d6) δ8.8 (s, 2H), 7.8 (bs, 2H), 2.6 (s, 3H).
[0067] Preparation 3
[0068] N-(3-Methyl-2-thienoyl)-S-methylthio-3,5-dichloro-4-pyridlimidate (13a)
[0069] Pyridine (0.51 mL, 6.3 mmol) was added dropwise to a slurry of 3-methyl-2-thiophenecarbonyl chloride (0.48g, 3.0 mmol) and S-methylthio-3,5-dichloropyridylimidinium iodide (1.05 g, 3.0 mmol) in 5 mL of 1,2-dichloroethane, under N 2 , at room temperature. After stirring at room temperature for 60 minutes the reaction mixture was poured into H 2 0 (25 mL) and extracted with ethyl acetate (3×25 ml). The combined organic extracts were washed with H 2 O (1×25 mL), saturated sodium chloride (1×25 mL), dried over anhydrous MgSO 4 , filtered and concentrated in vacuo to give 0.99 g of a yellow oil. This was chromatographed over silica gel (MPLC), eluting with 90% hexane/10% ethyl acetate. Isolation of the major product gave 0.827 g (80% yield) of the title compound as a faint yellow solid: mp 99-101° C. 1 H NMR (CDCl 3 ) δ8.51 (s, 2H), 7.45 (d, 1H), 6.94 (d, 1H), 2.64 (s, 3H), 2.49 (s, 3H).
[0070] Preparation 4
[0071] 1-Methyl-3-(3,5-dichloro-4-pyridyl)-5-(3-methyl-2-thienyl)[1,2,4]triazole (5a)
[0072] Methylhydrazine (0.225 mL, 4.2 mmol) was added dropwise to a solution of the N-acyl-S-methylthioimidate of Example 7 (0.725 g, 2.1 mmol) in 5 mL of toluene, under N 2 , at room temperature. After stirring at room temperature for 24 hours, TLC analysis showed a 2:1 mixture of starting material to product. An additional 0.2 mL of methylhydrazine was added and the mixture warmed to 40° C. After 5 hours TLC shows a 1:1 mixture of starting material to product. An additional 0.2 mL of methylhydrazine was added and stirring continued for 24 hours at 40-50° C. at which time TLC analysis indicated that all of the starting material had been consumed. The reaction mixture was concentrated in vacuo and the resultant yellow oil was chromatographed over silica gel (MPLC), eluting with 80% hexane/ 20% ethyl acetate. Isolation of the major product gave 0.422 g (65% yield) of the title compound as a faint yellow oil. 1 H NMR (CDCl 3 ) δ8.61 (s, 2H), 7.47(d, 1H), 7.02(d, 1H), 4.05(s, 3H), 2.40(s, 3H).
[0073] Preparation 5
[0074] [0074] 1 -n-Butyl-3-(2-chloro-6-fluorophenyl)-5-(3,4,5-trichlorothien-2-yl)-1H[1,2,4] triazole (5b)
[0075] A mixture of N-(3 ,4,5-trichloro-2-thienoyl)-S-methylthio-(2-fluoro,6-chloro)-phenylimidate (1.04 g, 2.5 mmol), n-butylhydrazine oxalate (1.78 g, 10 mmol) and triethylamine (4.04 g, 10 mmol) in toluene (20 mL) was heated at 105° C. for 16 h. Upon cooling down, the mixture was diluted with ether—CH 2 Cl 2 (3:1) and washed with 1N HCl, saturated NaHCO 3 and brine, dried over anhydrous Na 2 SO 4 , purified on silica gel by flash chromatography using ether—CH 2 Cl 2 —hexane (15:8:77) as eluting solvent to give 0.48 g of product (5b) as a white solid in 88% yield: mp 110-112° C. 1 H NMR (CDCl 3 ) δ7.36 (td, J=8.4, 5.4 Hz, 1H), 7.30 (dd, J=7.8, 1.2,1H), 7.10 (td, J=8.4, 1.8 Hz, 1H), 4.24 (t, J=7.2 Hz, 2H), 1.93 (quint, J=7.2 Hz, 2H), 1.31 (hextet, J=7.2 Hz, 2H), 0.91 (t, J =7.2 Hz, 2H). MS (EI): 437 (M + ), 402, 367, 226, 197, 156. Anal. Calcd for C 16 H 12 C 14 FN 3 S: C, 43.76; H, 2.75; N, 9.57. Found: C, 43.80; H, 2.71; N, 9.44.
[0076] The final step in the preparation of compounds of formula (1) involve the palladium catalyzed coupling of aryl bromides with terminal acetylene compounds. Therefore, the triazole intermediates of formula (5) were converted to either the aryl bromide or iodide of formula (6) using known procedures. Preparations 6 and 7, hereinafter, illustrate the two step preparation of the aryl bromide of formula (6).
[0077] Preparation 6
[0078] 1-Methyl-3-(2-chloro-6-fluorophenyl)-5-(3,4-dichlorothien-2-yl) [1 2,4]triazole
[0079] To a solution of 1-methyl-3-(2-chloro-6-fluorophenyl)-5-(3,4,5-trichlorothien-2-yl) (1,2,4)triazole (50.0 g, 126 mmol) in 250 mL of dry THF was added n-BuLi (60.4 mL of 2.5 M, 151 mmol) dropwise at −78° C. The resulting dark solution was stirred at −78° C. for 1 hour. TLC analysis (25%EtOAC/Pentane) indicates residual compound (5b). Added additional n-BuLi (4 mL, 1.6 mmol) and stirred at −78° C. for 1 hour. The reaction was quenched with saturated aqueous ammonium chloride and warmed to room temperature. The phases were separated and the aqueous residue was extracted with methylene chloride (100 mL). The organics were evaporated at reduced pressure, and the resulting dark oil was dissolved in methylene chloride, washed with brine, dried (sodium sulfate), filtered, and the solvent evaporated at reduced pressure to give the crude product as a dark oil. Flash chromatography (Silica Gel, 15%EtOAc/Pentane) affords 33.46 g (73%) of the desired product as a tan solid: mp 118-120° C 1 H NMR (CDCl 3 ) δ4.03 (s, 3H), 7.08-7.14 (Ar-m, 1H), 7.29-740 (Ar-m, 2H), 7.50 (s, 1H).
[0080] Preparation 7
[0081] 1-Methyl 3-(2-chloro-6-fluorophenyl)-5-(5-bromo-3,4-dichlorothien-2-yl) [1,2,4]triazole (6a)
[0082] To a mixture of 1-methyl-3-(2-chloro-6-fluorophenyl)-5-(3,4-dichlorothien-2-yl) [1,2,4]triazole (33.4 g, 92.1 mmol) and sodium acetate (7.6 g, 92.1 mmol) in acetic acid (250 mL) was added bromine (58.9 g, 368.4 mmol) dropwise at a rate which maintained the reaction temperature below 35° C. The resulting mixture was slowly heated to 70° C. and stirred for 2.5 hours, cooled to 50° C. and stirred overnight, and cooled to room temperature. TLC analysis (methylene chloride) indicates full consumption of the starting material. The reaction was slowly poured into a mixture of 10% aqueous sodium bisulfite and ice (300 mL), and the resulting pale yellow suspension was stirred for 20 minutes. The solids were collected by vacuum filtration, washed with water, and dissolved in methylene chloride. The organics were dried (sodium sulfate), filtered, and the solvent evaporated at reduced pressure to give 39.3 g (96%) of desired product as a tan solid: mp 178-180° C. 1 H NMR (CDCl 3 ) δ4.04 (s, 3H), 7.08-7.14 (Ar-m, 1H), 7.29-7.40 (Ar-m, 2H).
[0083] As stated above, compounds of formula (1) can be prepared by coupling the triazole intermediate of formula (6) with trimethylsilyl acetylene to give an intermediate of formula (8) ( J Am. Chem Soc. 1985, 107, 5670 and J Heterocylic Chem. 1995, 32, 1261). The trimethylsilyl group can be removed using standard conditions (J Med. Chem. 1987, 30, 1433 and Tetrahedron Lett. 1993, 34, 1223) to give the terminal acetylene intermediate of formula (9). Examples 3 and 4, hereinafter, illustrate the preparation of the trimethylsilyl acetylene intermediate of formula (8) and the terminal acetylene of formula (9). Example 3 1-Methyl-3-(2-chloro-6-fluorophenyl)-5-(3,4-dichloro-5-(2-trimethylsilyl-ethynyl)-thien-2-yl) [1 2,4]triazole (8a)
[0084] To a mixture of 1-methyl 3-(2-chloro-6-fluorophenyl)-5-(5-bromo-3,4-dichlorothien-2-yl)[1,2,4]triazole (30.0 g, 68.0 mmol), TMS-acetylene (25.0 g, 254.0 mmol), cuprous iodide (0.78 g, 4.1 mmol), and tetrakis(triphenylphosphine) palladium(0) (2.36 g, 2.0 mmol) in toluene (300 mL) was added triethylamine (8.6 g, 85.0 mmol) at room temperature. The mixture was heated to reflux and stirred for 3 hours. TLC analysis (methylene chloride) shows complete consumption of the starting material. The mixture was cooled to room temperature, poured into water, filtered through celite, and extracted with ethyl acetate (3×150 mL). The organics were washed with brine, dried (sodium sulfate), filtered, and the solvent removed under reduced pressure to give the crude product as a dark oil. Flash chromatography (Silica Gel, 10% EtOAc/Pentane) gives the product as a yellow solid. Trituration with hexanes affords 17.0 g (54%) of a white solid: mp 102-104° C. 1 H NMR (CDCl 3 ) δ0.30 (s, 9H), 4.02 (s, 3H), 7.08-7.25 (Ar-m,1H), 7.29-7.40 (Ar-m, 2H).
EXAMPLE 4
[0085] 1-Methyl-3-(2-chloro-6-fluorophenyl)-5-(3,4-dichloro-5-ethynvl-thien-2-yl)[1,2,4]triazole (9a)
[0086] To a mixture of 1-methyl-3-(2-chloro-6-fluorophenyl)-5-(3,4-dichloro-5-(2-trimethylsilyl-ethynyl)-thien-2-yl) [1,2,4]triazole (5.0g, 10.9 mmol) in methanol (20 mL) was added potassium carbonate (1.66 g, 12 mmol) at 0° C., and the resulting off-white suspension was stirred at 0° C. for 3.5 hours. TLC analysis (10% EtOAc/Pentane) indicates complete conversion to product. The reaction was acidified with 2 N hydrochloric acid and extracted with ether (2×100 mL). The organics were combined, washed with brine, dried (sodium sulfate), filtered, and the solvent evaporated under reduced pressure to give a tan solid. Trituration with pentane affords 4.06 g (96%) of product as a tan powder: mp 145-165 (slow decomposition) 1 H NMR (CDCl 3 ) δ3.77 (s, 1H,), 4.04 (s, 3H), 7.08-7.14 (m, 1H), 7.29-7.40 (Ar-m, 2H).
[0087] Compounds of formula (1) can be prepared by coupling the triazole intermediate of formula (9) with aryl halides of formula (10) under palladium catalysis, wherein Ar, R1, Q, and R2 are defined as in formula (1) above. Preparations 8 and 9, hereinafter, illustrate the preparation of the aryl halides of formula (10) from commercially available starting materials. Furthermore, examples 5 and 6, hereinafter, illustrates the synthesis of a compound of formula (1) utilizing the palladium-catalyzed reaction between triazole intermediate of formula (9) with aryl halides of formula (10).
[0088] Preparation 8
[0089] 3-Fluoro-4-iodotoluene (10a)
[0090] To a suspension of 2-fluoro-4-methylaniline (2.0 g, 16 mmol) in aqueous sulfuric acid (˜7 N) was added an aqueous solution of sodium nitrite (1.10 g, 16 mmol, 10 mL water) dropwise at 0° C. and the resulting light orange solution was stirred for 30 minutes. This solution was carefully poured into an aqueous solution of potassium iodide (3.98 g, 24 mmol, 16 mL water) at 80° C. and the resulting red mixture was stirred 1.5 hours at 80° C., and overnight at 50° C. The reaction was cooled to room temperature, poured into water (300 mL), and sodium bisulfite added until the light yellow color remained constant. The aqueous was extracted with diethyl ether (2×125 mL) and the organics were combined, washed with brine, dried (sodium sulfate), filtered, and the ether evaporated to give 2.5 g (66%) of crude product as a yellow green oil. Used without further purification. 1 H NMR (CDCl 3 ) δ2.32 (s, 3H,), 6.72 (dd, 1H, J=1.28 Hz, J=8.05 Hz), 6.88 (dd, 1H, J=1.28 Hz, JH=8.97 Hz), 7.58 (dd, 1H, J=1.08 Hz, J=6.78 Hz).
[0091] Preparation 9
[0092] 2-Iodo-6-methylpyridine (10b)
[0093] To a solution of 2-bromo-6-methylpyridine (2.0 g, 11.6 mmol) and sodium iodide (2.78 g, 18.6 mmol) in dry acetonitrile (13 mL) was added acetyl chloride (1.9 g, 24.4 mmol) dropwise, and the resulting light yellow suspension was heated to reflux. G.C. analysis after 16 hours at reflux indicated only 50% conversion. Added additional acetyl chloride (1 equivalent) and sodium iodide (0.8 equivalent) and refluxed for 16 hours. G.C. analysis indicated 90% conversion to desired product in addition to the expected bromo and chloro by-products. The reaction was cooled to room temperature, diluted with aqueous potassium carbonate and sodium bisulfite (75 mL, 10 and 5% respectively), and extracted with diethyl ether (2×75 mL). The organics were combined, washed with the carbonate/bisulfite solution, dried (sodium sulfate), filtered, and the solvent evaporated under reduced pressure to give 2.39 g (94%) of crude product as a dark oil. Used without further purification. 1 H NMR (CDCl 3 ) δ2.52 (s, 3H,), 7.10 (d, 1H, J=7.51 Hz), 7.20 (t, 1H, J=7.69 Hz, J=7.51 Hz), 7.58 (d, 1H, J=7.69 Hz). (Tetrahedron Lett. 1990, 31, 6757)
EXAMPLE 5
[0094] 3-(2-chloro-6-fluorophenyl)-5-(5-(2,4-difluorophenylalkynyl)-3,4-dichloro-2-thiophene)-1-methyl-1H-1,2,4-triazole (1b)
[0095] 2,4-Difluoroiodobenzene ((0.62g, 2.6 mmol), 3-(2-chloro-6-fluorophenyl)-5-(5-alkynyl-3,4-dichloro-2-thiophene)-1-methyl-1H-1,2,4-triazole (1.0g, 2.6 mmol) and copper(I) iodide (49mg, 0.26 mmol) was added to dry dimethylformamide (8 mL) and triethylamine (8 mL) and stirred at room temperature for 5 minutes. Bis-triphenylphosphinepalladium(II) chloride (180 mg, 0.26 mmol) was then added to the solution. This was stirred at 70° C. for 60 minutes, cooled to room temperature and poured into dilute hydrochloric acid (1M, 150 mL) and extracted with diethyl ether (3×40 mL). Combined organic layers were washed with water (2×70 mL) and brine (50 mL) before drying over magnesium sulphate. After concentration under reduced pressure, the residue was applied to a dry flash silica column and eluted with acetonitrile : methylene chloride : hexane(1:4:10). The second fraction was collected and recrystallised from hexane to give orange prisms. Yield 0.77g (60%). Mp 149° C. 1 H (CDCl 3 ) δ7.6 (m, 1H), 7.2-7.4 (m, 2H), 7.1(t, 1H), 6.9 (m, 2H), 4.0 (s,3H).
EXAMPLE 6
[0096] 1-Methyl-3-(2-chloro-6-fluorophenyl)-5-(3,4-dichloro-5-(2-(2-diethylaminopvrimidin-4-yl)ethynynl)-thien-2-yl) [1,2,4]triazole (1c)
[0097] To a mixture of 1-methyl-3-(2-chloro-6-fluorophenyl)-5-(3,4-dichloro-5-ethynyl-thien-2-yl)[1,2,4]triazole (0.50 g, 1.3 mmol), 2-chloro-4-iodopyrimidine (0.313 g, 1.3 mmol), and cuprous iodide (0.0025 g, 0.13 mmol) in triethylamine and N,N-dimethylformamide (1:1, 6 mL total volume) was added bistriphenylphosphine palladium(II)chloride and the resulting black mixture was heated to 60° C. and stirred for 2 hours. TLC analysis (10% EtOAc/hexane) shows complete consumption of the starting material. The reaction was cooled to room temperature, diluted with diethyl ether and washed with brine, dried (magnesium sulfate), filtered, and the solvent evaporated. Chromatography (SiO 2 , 10% EtOAc-Hex) afforded the product as a yellow solid. (188 mg, 28%) Mp 152-154° C. 1 H NMR δ8.46 (s, 2H), 7.29-7.38 (m, 2H), 7.08-7.14 (m, 1H) 4.05 (s, 3H) 3.66 (q, 4H) 1.21 (t, 6H).
[0098] Compounds of formula (1) can also be prepared by coupling the triazole intermediate of formula (6) with terminal alkynes of formula (7) under palladium catalysis, wherein Ar, R1, Q, and R2 are defined as in formula (1) above. Examples 7 and 8, hereinafter, illustrates the synthesis of a compound of formula (1) utilizing the palladium catalyzed reaction between triazole intermediate of formula (6) with terminal alkynes of formula (7). The terminal alkyne of formula (7) is commercially available or readily synthesized using standard methods.
[0099] EXAMPLE 7
[0100] 1-Methyl-3-(2-Chloro-6-fluorophenyl)-5-(3,4-dichloro-5-(2-(4-n-hexyl)phenyl)-ethynyl-thien-2-yl)-1H[1,2.4]triazole (1d)
[0101] To a heating-gun dried 50 mL three-neck flask equipped with a magnetic stirrer and electronic thermometer was charged with 3-(2-fluoro-6-chlorophenyl)-5-(3,4-dichloro-5-bromothien-2-yl)-1-methyl[1,2,4]triazole (0.441 g, 1.0 mmol), 4-n-hexylphenylacetylene (0.279 g, 1.5 mmol), dichloro-bis(triphenylphosphine)palladium(II) (0.070 g, 0.1 mmol), cuprous iodide (0.019 g, 0.1 mmol), DMF (2.5 mL), and triethylamine (2.5 mL) under nitrogen. The reaction mixture was heated at 51° C. for 2 h and poured into 1N HCl aqueous solution under stirring upon cooling down. The mixture was then extracted with ether (3×35 mL) and the combined organic layer was washed with saturated NaHCO 3 solution, water (2×30 mL), brine (30 mL), and dried over anhydrous MgSO 4 . After filtration followed by removal of the solvent, the residue was purified on silica gel by flash chromatography using 80:19:1 hexane—CH 2 Cl 2 —CH 3 CN as eluting solvent to provide 0.31 g of product as a brownish oil in 57% yield: 1 H NMR (CDCl 3 ) δ7.36 (d, J=8.1 Hz, 2 H), 7.13-7.26 (m, 2H), 7.06 (d, J=8.1 Hz, 2H), 6.97 (td, J=9.0, 1.5 Hz, 1H), 3.91 (s, 3H), 2.50 (t, J=7.5 Hz, 2H), 1.47 (m, 2H), 1.12-1.24 (m, 6H), 0.76 (t, J=6.6 Hz, 3H).
EXAMPLE 8
[0102] 1-Methyl-3-(2-Chloro-6-fluorophenyl)-5-(2,3-dichloro-4-(2-(4-trifluoromethyl)phenyl)-ethynyl-phenyl)-1 H[1,2,4]triazole (1 e)
[0103] A dry 50 mL three-neck flask cooled in an ice-water bath was charged with 3-(2-chloro-6-fluorophenyl)-5-(2,3-dichloro-4-iodophenyl)-1-methyl[1,2,4]triazole (0.241 g, 0.5 mmol), 4-trifluoromethyl phenylacetylene (0.128 g, 0.75 mmol), dichlorobis(triphenylphosphine)palladium(II) (0.035 g, 0.05 mmol), cuprous iodide (0.0095 g, 0.05 mmol), DMF (1.7 mL), and triethylamine (1.7 mL) under nitrogen atmosphere. The reaction mixture was continued to stir at 0° C. until the reaction completed monitored by TLC (1h). The mixture was poured into aqueous acidic solution (1N HCl or H 2 SO 4 ), and extracted with ether—CH 2 Cl 2 (4:1). The organic layer was washed with water, saturated NaHCO 3 solution and brine successively, and dried over anhydrous MgSO 4 . After filtration followed by removal of the solvent, the residue was purified on silica gel by flash chromatography using 4:1:15 ether—CH 2 Cl 2 —hexane as eluent to provide 0.239 g of product as a white solid in 92% yield: mp 138-140° C. 1 H NMR (CDCl 3 ) δ7.72 (d, J=8.4 Hz, 2H), 7.66 (d, J=8.4 Hz, 2H), 7.64 (d, J=8.0 Hz, 1H), 7.50 (d, J=8.0 Hz, 1H), 7.30-7.40 (m, 2H), 7.12 (m, 1H), 3.91 (s, 3H).
[0104] The compounds identified in the following Tables 1-7 were prepared using the procedures illustrated in the foregoing examples, and the compounds were tested against tobacco budworm, beet armyworm, cabbage looper, cotton aphid, two-spotted spider mite, sweetpotato whitefly, brown planthopper, and green leafhopper using procedures described hereinafter.
TABLE 1 Compound # R2 mp TBW BAW CL CA SM WF BPH GLH 1 —Si(CH 3 ) 3 102-104 A A A E B F F B 2 —H 145-165 G G F D G G D F 3 —C(CH 3 ) 3 oil D G A A B F 4 —Ph 133-135 F A A B D F E G 5 —CH 2 CH 3 oil G G G B G F F F 6 160-162 G A A A G G F F 7 140-142 F A A D 8 155-157 F A A F A G F F 9 135 A B A F F 10 153-154 G A D B F G E G 11 118-119 A B A D G G G E 12 156-157 G A A C G F F F 13 101-102 G A A C G F G G 14 104-105 A A A A G F F G 15 153-154 F D D D G F F F 16 155-157 G F D F G F F F 17 205-207 G G G F F D F 18 160-161 B A A F A G E F 19 123-125 B A A G E G D F 20 105-107 A A A D B F F G 21 127-129 G G G F G G F G 22 165-166 G G G F G D F F 23 149 G A A F G F G F 24 140-142 G A A D G F F F 25 75-77 A A A D G E D F 26 161 A G A F G D C F 27 150 D A A G F D E F 28 133-134 A A A F G D F D 29 154-156 A G A E G F F F 30 128-131 G A G F G E B F 31 123-125 G A A D G F F F 32 165-167 G G G F G C D F 33 148-150 G G G F G D F F 34 112-114 G G A E G D D F 35 131-135 G G A E G F F G 36 144-145 G G A E G F D D 37 141 F D A D B E F F 38 oil G G G D G F 39 oil G G G B G G F F 40 119-122 G B G B G G 41 152-154 D A B F F F E G 42 129-132 B D A C G F F F 43 183-184 G G G F G F G F 44 133-135 G G G F G F G G 45 182-183 G G G F G F F F 46 120-124 G D D E G F F G 47 103-105 A A A C G G F G 48 165-167 G A A D G G F G 49 118-120 D A A F G F F G 50 130-133 G G A D G F D F 51 155-158 B A A F G F F F 52 123-125 A A A D G F G G 53 107-108 F A A E G F F G 54 oil A A B E G F F F 55 oil D A A F G F F F 56 84-86 A A A E G F F G 57 143-144 G G G G G F G F 58 166-168 G G G F G F F F 59 83-85 G G G F G F F F 60 137-138 G A A F G E G G 61 189-191 G G G F G F F F 62 153-155 G G G F G F F F 63 158-161 G D A G G F 64 155-159 G B A G G F 65 96-98 A A A F
[0105] [0105] TABLE 2 compound Q mp TBW BAW CL CA SM WF BPH GLH 66 120-122 G GG G B G F G F 67 glass B A G A B F G G 68 114-116 G G G A G F F F 69 155-157 G G G E F G F 70 116-117 G G G C F G G 71 133-134 G G G A F F G 72 105-106 G A B C F F F G
[0106] [0106] TABLE 3 compound number Ar mp TBW BAW CL CA SM WF BPH GLH 73 92 A A F F G F A G 74 147 F F G F G F F F 75 CH 3 — 75-77 G G G F G F C F 76 125 G A G G F F F
[0107] [0107] TABLE 4 compound Ar mp TBW BAW CL CA SM WF BPH GLH 77 149 G A A F D D F F 78 CH 3 — 133-135 G A G F G D F F 79 179 G G G F G D F F
[0108] [0108] TABLE 5 compound R1 mp TBW BAW CL CA SM WF BPH GLH 80 H 209-211 G G G G G F 81 —CH 2 CH 3 oil F A D F G F 82 -nC 4 H 9 oil G D A F G F 83 135-137 G G G F G F 84 125-126 G G G F G F
[0109] [0109] TABLE 6 compound Q mp TBW BAW CL CA SM WF BPH GLH 85 oil G G G B G F E F 86 77-80 G G G E C F F F 87 oil F F F 88 162-164 G G G D G F G F 89 oil G G G B G F G F
[0110] [0110] TABLE 7 compound R2 mp TBW BAW CL CA SM WF BPH GLH 90 oil G A A B G F E F 91 147-148 G A B A G F F F 92 123-125 G A A A F F F F 93 oil G A A E G F F F 94 138-140 D A A B G F 95 148-150 F B B C G F 96 —Si(CH 3 ) 3 121-123 F A A D D F 97 —H 125-127 G G G B G F 98 oil A A A C In each case the rating scale is as follows % Control Rating 90-100 A 80-89 B 70-79 C 60-69 D 50-59 E less than 50 F inactive G
[0111] Insecticide and Miticide Utility
[0112] The compounds of the invention are useful for the control of insects, mites, and aphids. Therefore, the present invention also is directed to a method for inhibiting an insect, mite, or aphid which comprises applying to a locus of the insect or mite an insect- or mite-inhibiting amount of a compound of formula (1).
[0113] The compounds are useful for reducing populations of insects and mites and are useful in a method of inhibiting an insect or mite population which comprises applying to a locus of the insect or mite an effective insect- or mite-inactivating amount of a compound of formula (1). The “locus” of insects or mites is a term used herein to refer to the environment in which the insects or mites live or where their eggs are present, including the air surrounding them, the food they eat, or objects which they contact. For example, plant-ingesting insects or mites can be controlled by applying the active compound to plant parts that the insects or mites eat, particularly the foliage. It is contemplated that the compounds might also be useful to protect textiles, paper, stored grain, or seeds by applying an active compound to such substance. The term “inhibiting an insect or mite” refers to a decrease in the numbers of living insects or mites, or a decrease in the number of viable insect or mite eggs. The extent of reduction accomplished by a compound depends, of course, upon the application rate of the compound, the particular compound used, and the target insect or mite species. At least an inactivating amount should be used. The terms “insect-inactivating amount” and “mite-inactivating amount” are used to describe the amount, which is sufficient to cause a measurable reduction in the treated insect or mite population. Generally an amount in the range from about 1 to about 1000 ppm active compound is used.
[0114] In a preferred embodiment, the present invention is directed to a method for inhibiting a mite or aphid which comprises applying to a plant an effective mite- or aphid- inactivating amount of a compound of formula (1).
[0115] Insecticidal test for tobacco budworm ( Heliothis virescens ), beet armyworm ( Spodoptera exigua ), and cabbage looper ( Trichoplusia ni ).
[0116] To prepare test solution, the test compound was formulated at 400 ppm in 7.5 mL of 2 acetone: 1 tap water. 250 μl of the test solution was pipetted upon the surface of 8 mL of lepidopteran diet (modified Shorey) contained in each of five one-ounce plastic cups (one cup=1 replication). A second-instar beet armyworm was placed upon the treated diet in each cup once the solvent had air-dried. The solutions remaining after completing applications to the one-ounce cups were then used as leaf-dip solutions for 3.5 cm leaf discs cut from cabbage leaves and cotton cotyledons. Five discs of each type of plant were dipped until thoroughly coated into each rate of each compound (=5 replications of each treatment). After air-drying, the treated leaf discs were placed individually into one-ounce plastic cups. Each dried, treated cotton cotyledon disc was infested with a 2 nd instar tobacco budworm larva, and each cabbage leaf disc was infested with a 2 nd instar cabbage looper larva. Cups containing the treated substrates and larvae were capped and then held in a growth chamber at 25° C., 50-55% R.H., and 14 hr light: 10 hr dark for 5 days. The number of dead insects of 5 per species per treatment was then determined and the results are given in Table 1-7.
[0117] Insecticidal test for cotton aphid ( Aphis gossvpii )
[0118] To prepare spray solutions, 1 mg of each test compound was dissolved into 2 nL of a 90:10 acetone:ethanol solvent. This 1 mL of chemical solution was added to 19 mL of water containing 0.05% Tween 20 surfactant to produce a 50 ppm spray solution.
[0119] Squash cotyledons were infested with cotton aphid (all life stages)16-20 hours prior to application of spray solution. The solution was sprayed on both sides of each infested squash cotyledon (0.5 mL X 2 each side) with a sweeping action until runoff. The plants were allowed to air dry and held for 3 days in a controlled room at 26° C. and 40% RH after which time the test was graded. Grading was by actual count using a dissecting microscope and comparison of test counts to the untreated check. Results are given in Table 1-7 as percent control based on population reduction versus the untreated.
[0120] Insecticidal test for two-spotted spider mite ( Tetranychus urticae )
[0121] Ovicide Method:
[0122] Ten adult female two-spotted spider mites were placed on eight 2.2 cm leaf discs of cotton leaf, allowed to oviposit over 24 hours, and thereafter removed. The leaf discs were sprayed with 100 ppm test solutions using a hand syringe, then allowed to dry with sixteen discs left untreated as a negative control. Discs were placed on an agar substrate and held at 24° C. and 90% relative humidity for 6 days. Percent control based on the number of hatched larvae on treated discs and the number on untreated discs is reported in Table 1-7.
[0123] Insecticidal test for Sweetpotato Whitefly ( Bemisia tabacia )
[0124] Four mg of each test compound were dissolved by adding 4 mL of a 90:10 acetone:ethanol solvent mixture to the vial containing the sample compound. This solution was added to 16 mL of water containing 0.05% Tween 20 surfactant to produce
[0125] 20 ml of an 200 ppm spray solution.
[0126] Five-week-old cotton plants reared in a greenhouse were stripped of all foliage except for the two uppermost true leaves that were greater than 5 cm in diameter. These plants were then placed into a laboratory colony of whiteflies for two days for oviposition by the colony females. All whiteflies were then removed from the test plants with pressurized air. The spray solution was then applied to the test plants with a hand-held syringe fitted with hollow cone nozzle. One mL of spray solution was applied to each leaf top and bottom for a total of 4 mL per plant. Four replications of each test compound utilized a total of 16 mL spray solution. Plants were air dried and then placed in a holding chamber (28° C. and 60% RH) for 13 days. Compound efficacy was evaluated by counting, under an illuminated magnifying glass, the number of large nymphs (3rd-4th instar) per leaf. Percent control based on reduction of large nymphs of a test compound compared to solution-only (no test compound) sprayed plants is reported in Table 1-7.
[0127] Insecticidal test for Brown Planthopper ( Nilaparvata lugens ) and Green Leafhopper ( Nephotettix cincticeps )
[0128] Ten mg of test substance were dissolved in 1 mL of acetone, making a 10,000 ppm solution. Out of this 10,000 ppm solution, 0.1 ml (100 microlitre) are added to 99.9 ml of water to produce 100 ml of a 10 ppm test solution. Twenty-five ml of 10 ppm test solution were added to each of four glass cylinder cages. Within each cylinder, roots of three to five four-week old rice seedlings are submerged in the test. Five laboratory-reared 3 rd instar nymphs of either brown planthopper or green leafhopper were introduced into the glass cylinder cages. The cylinders (four replicates per treatment) were held in a growth chamber at 28° C. and 75% relative humidity, with a photoperiod of 14 hours. Mortality is observed 6 days after infestation of insects into the test arena. Results are given in Table 1-7 as percent mortality.
[0129] In addition to being effective against mites, aphids, and insects when applied to foliage, compounds of formula (1) have systemic activity. Accordingly, another aspect of the invention is a method of protecting a plant from insects which comprises treating plant seed prior to planting it, treating soil where plant seed is to be planted, or treating soil at the roots of a plant after it is planted, with an effective amount of a compound of formula (1).
[0130] Compositions
[0131] The compounds of this invention are applied in the form of compositions which are important embodiments of the invention, and which comprise a compound of this invention and a phytologically-acceptable inert carrier. The compositions are either concentrated formulations which are dispersed in water for application, or are dust or granular formulations which are applied without further treatment. The compositions are prepared according to procedures and formulae which are conventional in the agricultural chemical art, but which are novel and important because of the presence therein of the compounds of this invention. Some description of the formulation of the compositions will be given, however, to assure that agricultural chemists can readily prepare any desired composition.
[0132] The dispersions in which the compounds are applied are most often aqueous suspensions or emulsions prepared from concentrated formulations of the compounds. Such water-soluble, water-suspendable or emulsifiable formulations are either solids, usually known as wettable powders, or liquids usually known as emulsifiable concentrates or aqueous suspensions. Wettable powders, which may be compacted to form water dispersible granules, comprise an intimate mixture of the active compound, an inert carrier, and surfactants. The concentration of the active compound is usually from about 10% to about 90% by weight. The inert carrier is usually chosen from among the attapulgite clays, the montmorillonite clays, the diatomaceous earths, or the purified silicates. Effective surfactants, comprising from about 0.5% to about 10% of the wettable powder, are found among the sulfonated lignins, the condensed naphthalenesulfonates, the naphthalenesulfonates, the alkylbenzenesulfonates, the alkyl sulfates, and nonionic surfactants such as ethylene oxide adducts of alkyl phenols.
[0133] Emulsifiable concentrates of the compounds comprise a convenient concentration of a compound, such as from about 50 to about 500 grams per liter of liquid, equivalent to about 10% to about 50%, dissolved in an inert carrier which is either a water miscible solvent or a mixture of water-immiscible organic solvent and emulsifiers. Useful organic solvents include aromatics, especially the xylenes, and the petroleum fractions, especially the high-boiling naphthalenic and olefinic portions of petroleum such as heavy aromatic naphtha. Other organic solvents may also be used, such as the terpenic solvents including rosin derivatives, aliphatic ketones such as cyclohexanone, and complex alcohols such as 2-ethoxyethanol. Suitable emulsifiers for emulsifiable concentrates are chosen from conventional nonionic surfactants, such as those discussed above.
[0134] Aqueous suspensions comprise suspensions of water-insoluble compounds of this invention, dispersed in an aqueous vehicle at a concentration in the range from about 5% to about 50% by weight. Suspensions are prepared by finely grinding the compound, and vigorously mixing it into a vehicle comprised of water and surfactants chosen from the same types discussed above. Inert ingredients, such as inorganic salts and synthetic or natural gums, may also be added, to increase the density and viscosity of the aqueous vehicle. It is often most effective to grind and mix the compound at the same time by preparing the aqueous mixture, and homogenizing it in an implement such as a sand mill, ball mill, or piston-type homogenizer.
[0135] The compounds may also be applied as granular compositions, which are particularly useful for applications to the soil. Granular compositions usually contain from about 0.5% to about 10% by weight of the compound, dispersed in an inert carrier which consists entirely or in large part of clay or a similar inexpensive substance. Such compositions are usually prepared by dissolving the compound in a suitable solvent and applying it to a granular carrier which has been pre-formed to the appropriate particle size, in the range of from about 0.5 to 3 mm. Such compositions may also be formulated by making a dough or paste of the carrier and compound and crushing and drying to obtain the desired granular particle size.
[0136] Dusts containing the compounds are prepared simply by intimately mixing the compound in powdered form with a suitable dusty agricultural carrier, such as kaolin clay, ground volcanic rock, and the like. Dusts can suitably contain from about 1% to about 10% of the compound.
[0137] It is equally practical, when desirable for any reason, to apply the compound in the form of a solution in an appropriate organic solvent, usually a bland petroleum oil, such as the spray oils, which are widely used in agricultural chemistry.
[0138] Insecticides and acaricides are generally applied in the form of a dispersion of the active ingredient in a liquid carrier. It is conventional to refer to application rates in terms of the concentration of active ingredient in the carrier. The most widely used carrier is water.
[0139] The compounds of the invention can also be applied in the form of an aerosol composition. In such compositions the active compound is dissolved or dispersed in an inert carrier, which is a pressure-generating propellant mixture. The aerosol composition is packaged in a container from which the mixture is dispensed through an atomizing valve. Propellant mixtures comprise either low-boiling halocarbons, which may be mixed with organic solvents, or aqueous suspensions pressurized with inert gases or gaseous hydrocarbons.
[0140] The actual amount of compound to be applied to loci of insects, mites, and aphids is not critical and can readily be determined by those skilled in the art in view of the examples above. In general, concentrations of from-10 ppm to 5000 ppm of compound are expected to provide good control. With many of the compounds, concentrations of from 100 to 1500 ppm will suffice. For field crops, such as soybeans and cotton, a suitable application rate for the compounds is about 0.5 to 1.5 lb/A, typically applied in 5-20 gal/A of spray formulation containing 1200 to 3600 ppm of compound. For citrus crops, a suitable application rate is from about 100 to 1500 gal/A spray formulation, which is a rate of 100 to 1000 ppm.
[0141] The locus to which a compound is applied can be any locus inhabited by an insect or arachnid, for example, vegetable crops, fruit and nut trees, grape vines, and ornamental plants. Inasmuch as many mite species are specific to a particular host, the foregoing list of mite species provides exemplification of the wide range of settings in which the present compounds can be used.
[0142] Because of the unique ability of mite eggs to resist toxicant action, repeated applications may be desirable to control newly emerged larvae, as is true of other known acaricides.
[0143] The following formulations of compounds of the invention are typical of compositions useful in the practice of the present invention.
A. 0.75 Emulsifiable Concentrate Compound of formula (1) 9.38% “TOXIMUL D”(nonionic/anionic surfactant blend) 2.50% “TOXIMUL H’(nonionic/anionic surfactant blend) 2.50% “EXXON 200”(naphthalenic solvent) 85.62% B. 1.5 Emulsifiable Concentrate Compound of formula (1) 18.50% “TOXIMUL D” 2.50% “TOXIMUL H” 2.50% “EXXON 200” 76.50% C. 1.0 Emulsifiable Concentrate Compound of formula (1) 12.5% N-methylpyrrolidone 25.00% “TOXIMUL D” 2.50% “TOXIMUL H” 2.50% “EXXON 200” 57.50% D. 1.0 Aqueous Suspension Compound of formula (1) 12.00% “PLURONIC P-103”(block copolymer of propylene oxide and 1.50% ethylene oxide, surfactant) “PROXEL GXL”(biocide/preservative) .05% “AF-100”(silicon based antifoam agent) .20% “REAX 88B”(lignosulfonate dispersing agent) 1.00% propylene glycol 10.00% veegum .75% xanthan .25% water 74.25% E. 1.0 Aqueous Suspension Compound of formula (1) 12.50% “MAKON 10”(10 moles ethyleneoxide nonylphenol surfactant 1.00% “ZEOSYL 200”(silica) 1.00% “AF-100” 0.20% “AGRIWET FR”(surfactant) 3.00% 2% xanthan hydrate 10.00% water 72.30% F. 1.0 Aqueous Suspension Compound of formula (1) 12.50% “MAKON 10” 1.50% “ZEOSYL 200”(silica) 1.00% “AF-100” 0.20% “POLYFON H”(lignosulfonate dispersing agent) 0.20% 2% xanthan hydrate 10.00% water 74.60% G. Wettable Powder Compound of formula (1) 25.80% “POLYFON H” 3.50% “SELLOGEN HR” 5.00% “STEPANOL ME DRY” 1.00% gum arabic 0.50% “HISIL 233” 2.50% Barden clay 61.70% H. 1.0 Aqueous Suspension Compound of formula (1) 12.40% “TERGITOL 158-7” 5.00% “ZEOSYL 200” 1.0% “AF-1G0” 0.20% “POLYFON H” 0.50% 2% xanthan solution 10.00% tap water 70.90% I. 1.0 Emulsifiable Concentrate Compound of formula (1) 12.40% “TOXIMUL D” 2.50% “TOXIMUL H” 2.50% “EXXON 200” 82.60% J. Wettable Powder Compound of formula (1) 25.80% “SELLOGEN HR” 5.00% “POLYFON H” 4.00% “STEPANOL ME DRY” 2.00% “HISIL 233” 3.00% Barden clay 60.20% K. 0.5 Emulsifiable Concentrate Compound of formula (1) 6.19% “TOXIMUL H” 3.60% “TOXIMIUL D” 0.40% “EXXON 200” 89.81% L. Emulsifiable Concentrate Compound of formula (1) 5 to 48 surfactant or surfactant blend 2 to 20% Aromatic Solvent or Mixture 55 to 75%
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3-(Substituted aryl)-5-{substituted aryl-(alkynyl-aryl)}-[1,2,4]- triazole compounds are useful as insecticides and acaricides. New synthetic procedures and intermediates for preparing the compounds, pesticide compositions containing the compounds, and methods of controlling insects and mites using the compounds are also provided.
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CROSS-REFERENCES TO RELATED APPLICATIONS
This application claims the benefit of Provisional Application Ser. No. 60/110,164, filed Nov. 27, 1999.
BACKGROUND OF INVENTION
1. Field of Invention
Deck drainage systems.
2. Brief Summary of Invention
The invention can be briefly described as corrugated panels over a wooden grid, these supported at the high-side by a high-ledger and at the low-side by low-ledger, with guttering attached at the low-side.
PRIOR ART
Moore U.S Pat. No. 5,765,328, Mickelsen U.S. Pat. No. 4,860,502, Thibodeau U.S. Pat. No. 4,065,883 describe drainage systems which fit under decks between joists. These are difficult to install, unsightly, and would tend to clog up with debris. A traditional way of fastening panels directly to the bottom of joists and shims have the same problems.
OBJECTS AND ADVANTAGES
This invention protects property from precipitation, lingering moisture and wet deleterious conditions. It makes space more useable and comfortable affordable.
By its modularity the preferred embodiment of this invention enhances ease of fabrication and installation, and enhances the feasibility of pre-manufacturing the system as a kit for installation by homeowners.
It aesthetically enhances appearances under existing decks. It is unobtrusive because of its hidden and sleek components.
Its unobtrusiveness and aesthetic appeal enhances the ability to obtain permission for use in communities under strict design covenants.
The preferred implementation is not classified as structural—thereby not requiring building permits, in Fairfax County, Va., one of the more highly regulated Counties in the United States. (Having to obtain permits can involve a lot of time and cost, making a good product unmarketable.)
The preferred implementation can be taken apart and reinstalled due to bolt and screw fastening means and the snap/gravitational holding means as well as its light-weight. This can be useful in situations when a deck is rebuilt or the installation of the implementation is moved from one deck to another.
The preferred implementation is easy to maintain, due to its holding means, most members can be easily lifted, unsnapped, slid or otherwise temporarily displaced from position without requiring tools.
DRAWING FIGURES
FIG. 1 is a profile of the invention.
FIG. 2 & FIG. 3 are details of the low-ledger fitting into the joist of an endboard
FIG. 4 shows how cross-members and spacers are disposed with the sloping members and the highledger, respectively.
FIG. 5 is a detail of a cross-member bracket and how it is disposed.
DESCRIPTION OF THE INVENTION
Some specially made elements are common among several components. Nominal 2×2(s),hereinafter called 2×2(s) are constituents of the high-ledger, the low-ledger, as well as the elongated sloping members. The 2×2s are pre-manufactured by ripping 2×4s in half. They have actual dimension of about 1.5″ by 1{fraction (11/16)}-inch and they have a smooth straight cut surface on one side. Nominal 1×2(s),hereinafter called 1×2(s) are constituents of the cross-members, spacers and trim. The 1×2s are pre-manufactured by ripping 2×2 fence pickets in half. They have actual dimension of about 1.5-inches by {fraction (9/16)}-inches, and they have a smooth straight cut surface on one side. Nominal {fraction (5/4)} deck boards have actual dimensions of 1-inch×5.5-inches. All wood members are pressure treated and the 2×4s from which the 2×2s are cut are dried after treatment for increased stability.
The high-ledger 1 comprises a 2×2 1 a fastened to the side of a {fraction (5/4)}×6 deck board 1 b . The 2×2 extends the full length of the deck board. The cut side of the 2×2 faces upward, representing an upper-face, and is about 1.75-inches below the top of the deck board, the 1.75-inches of deck board representing an upstanding-face.
The low-ledger 2 comprises a 2×2 2 a fastened to the side of a {fraction (5/4)}×6 deck board 2 b . The 2×2 extends the full length of the deck board less about 2-inches at both ends. The cut side of the 2×2 faces upward, representing an upper-face, and is about 1.25-inches below the top of the deck board, the 1.25-inches of deck board representing an upstanding-face. Fillers 2 c , comprising plates of ½-inch plywood, with about a 5-inch by 2-inch face area dimension are fastened to the side of the deck-board, one on each end and on the same side as the 2×2. The outside edges of the plates are roughly flush with the deck board at its ends and at its lower edge. The ends of the low-ledger fit snugly into the joist hanger 7 of endboards 6 , one of which is disposed at each end of the low-ledger.
Each endboard 6 comprises 2 sheets of ¾-inch B/C plywood fastened together with screws and/or nails, the higher quality faces exposed, to make a 1.5-inch thick plate with a face dimensions of 10-inches wide by 16-inches long, the width extending horizontally, the length extending vertically. Each endboard is fastened to a deck joist using two 3.5-inch×¼-inch hex bolts with nuts and washers. Nominal 6-inch joist hangers 7 are disposed on a face of each endboard, ⅛-inch above the bottom edge of the endboard.
A plurality of elongated sloping members 3 , each having two ends, are comprised of 2×2s 3 a and finish nails 3 b , with the cut sides of the 2×2s facing upwards, representing an upper-face. The 1 {fraction (11/16)}-inch dimension of the sloping members normal to the upper-face, represent sides of the sloping members. The nails are finishing nails with a shaft of about {fraction (1/16)}-inch diameter and head of about ⅛-inch diameter. The nails are partially driven into the cut side so that nails protrude about ⅜″ above the 2×2s, each nail representing a small projection above the upper-face. The nails are disposed approximately ¼ from the edges of the elongated sloping members every about 2-feet or less. One end, of each elongated sloping member rests on the 2×2, or the upper-face, of the high-ledger, the other end rests on the 2×2, or the upper-face, of the low-ledger. The sloping members are disposed perpendicularly to the low-ledger and generally uniformly about 20 to 24-inches on-center from each other generally about the full extent of the low-ledger.
A plurality of spacers 5 , made from 1×2s and generally having a length of about 22⅜-inches are disposed at the high-ledger between the sloping members and fastened to the {fraction (5/4)} board with two screws, the cut side facing the {fraction (5/4)} board. The spacers are disposed so that their top edges are at the approximate same elevation as the top of the ends of the sloping members.
A plurality of cross-members 4 a , is comprised of slats 4 a , cut from 1×2s and generally having a length of 22⅜-inches, and of plastic brackets 4 b . The brackets have a thickness of about ⅛-inch, representing a diminutive thickness, and a face dimension of about ¾-inches by 3-inches, each bracket with an upper-face and an under-side. The brackets are fastened to the cut face of the slats, one bracket at each end of each slat. The 3-inch dimension of each bracket extends parallel with the length of each slat and an edge of each bracket projects about ⅝-inches beyond each end of each stat. The 22⅜-inch slates represent a middle-portion of each cross-member. The ends of the slats and the approximate ⅝-inch projections, of the plastic brackets beyond the ends of each slat, represent end-portions of each cross-member. At each bracket, a hole, or a hollow, 4 b 1 having about a ⅛-inch diameter is drilled with its center disposed at the projected portion of the bracket, about ¼-inches from the edge of the slat, and at the approximate center of the ¾-inch dimension.
The cross-members are disposed perpendicularly to the sloping members, the cut side of the slats facing upwards, the brackets of the cross-members resting on the sloping members, the projecting nails of the sloping members project through the hollows of the brackets, holding the brackets in place. The upper-face and sides of the sloping members together with the small projections therefore represent an interface with the end-portions of the cross-members.
The cross-members in combination with the sloping members, the spacers, and the {fraction (5/4)} board of the low-ledger form a substantially planer grid with a upper-surface. The high-ledger is at an elevation higher than the low-ledger such that the slope of each sloping members is down about ½-in per foot from its end at the high-ledger to its end at the low-ledger.
A plurality of corrugated plastic panels 7 rest on the upper-surface of the planer grid. Each panel has a nominal width of 2-feet and an actual width of about 26-inches. The panels are oriented so the rise and the fall of their corrugation is parallel to the low-ledger. The panels overlap about 2-inches, and are thus held to each other due to the corrugation. The panels extend approximately from the face of the {fraction (5/4)} board of the high-ledger to about 2-inches beyond the {fraction (5/4)} board at the low-ledger. The panels are held into place by clips 8 at the low-ledger and by flashing 9 at the high-ledger.
The clips 8 are made from ¾-inch by 4-inch strips of galvanized sheet metal. Each strip is bent along its long dimension ½-inch from one of its ends 90-degrees up, and bent at 1-inch from the same end 90-degrees up to produce a j-configuration, with a slot ½-inch deep and ½-inch wide. The clips are fastened by nail or screw to the upper-edge of the lower-ledger's {fraction (5/4)} board generally one clip for each sloping members, in line with the sloping members, projecting horizontally about 1-inch beyond the upper-edge comer of the {fraction (5/4)} board away from the sloping member. The clips represent a panel holding means in the proximity of the low-ledger.
The flashing 9 at the higher-side ledger is L-shaped, with the short leg about 1.75-inches long and the other leg about 2-inches long. The flashing is disposed with the short leg fastened to the face of the {fraction (5/4)} board with the bend of the L-shaped flashing at about the same elevation as the upper edge of the {fraction (5/4)} board, the long leg projecting over the spacer with a slightly downward slope. Generally the flashing extends the full length of the high-ledger. The flashing represents a panel holding means in the proximity of the high-ledger.
Having an aluminum gutter 10 with a flat side, the flat side is fastened, by screw, to the outside face of the {fraction (5/4)} board of the lower-side fascia, about one screw per foot length of gutter. The flat side has a vertical dimension of about 3.5-inches. The screws are disposed about 1- inch form the top edge of the gutter's flat side. The gutter has a high-end and a low-end. The elevation of the gutter drops at least 1-inch in 20-feet from the high end to the low end. The upper-edge of the flat side at the gutter's high-end is at about the same elevation as the upper edge of the low-ledger's {fraction (5/4)} board. The upper-edge of the flat side at the gutter's low end is up to a maximum of about 2-inches below the upper-edge of the flat side at the gutter's high end. A downspout protrudes from the gutter near its low end, at a post of the deck.
Other embodiments of the present invention are possible and preferred in some situations. Various plastic or sheet metal panels can be used. Fiber-reinforced plastic panels are preferred due to their lightness, stability and strength. The sloping members can be wood, metal, or plastic. Wood members are preferred mostly due to aesthetics. The equivalents of cross-members could be of wood, metal or plastics. One inexpensive embodiment is a plurality of metal j-beads, 2 to 10 feet long, with the two short legs notched out at the locations of the sloping members, with nails projecting from the sloping members to hold the j-beads in place. If looking for strength, another embodiment has been the use of 2×4s for sloping members, 2×6s with joist hangers replacing the low-ledger and the high-ledger.
In some situations it is preferable to attach a 2×2 to the side of the adjacent structure, in place of the high-ledger {fraction (5/4)} board. In some situations it is preferable to eliminate the endboards, attaching the low-ledger directly to deck post, and providing a fascia board to hide the gutter. Where at beam or fascia board presents a flat surface, the gutter should be fastened to these rather than the low-ledger's {fraction (5/4)} board to distribute the weight.
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This invention comprises a grid structure that with the addition of panels and panel holding components, and the further addition of a gutter and downspout provides an effective under-deck water shedding system where the grid and panel components generally are set or slid into place and generally can be lifted or slid out of place for adjustment, maintenance or removal.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser. No. 09/732,472, filed Dec. 7, 2000, the entire contents of which are incorporated by reference herein.
FIELD OF THE INVENTION
[0002] The invention relates to water heaters, and more particularly to water heaters adapted to be mounted on the roof of a building.
BACKGROUND
[0003] It is known to provide a water heater within a building, and to mount other equipment (e.g., HVAC equipment) on the roof of a building. A primary concern with rooftop equipment is the load imposed on the roof by the weight of the equipment. Most rooftop equipment is supported on the roof by a roof curb. The roof curb provides a weather-tight seal between the equipment and the roof, and distributes the weight load of the equipment to the building's roof. The roof curb also prevents leakage of water into the building and equipment in the event of a roof flood. Roof curbs are typically built to match the pitch of the roof so that the equipment mounts on a level surface. Rooftop equipment is typically raised to the roof with a crane and set on the roof curb. A foam sealing tape is often used between the bottom of the equipment and the roof curb to provide a weather-tight seal.
[0004] Many commercial buildings include a wall around the rooftop to screen the rooftop equipment from view. Much of the HVAC equipment currently installed on rooftops is enclosed in a rectangular cabinet, and has a sufficiently low profile to be not visible from the ground level.
SUMMARY
[0005] The present invention identifies several advantages to providing a water heater on the roof of a building. In commercial applications, one factor affecting many aspects of some businesses, and particularly retail and restaurant businesses, is floor space. Moving a water heater out of a building and positioning it on the building's roof may permit more floor space to be used for conducting business. In addition to potentially freeing up floor space and the need for a separate boiler room in a building, the present invention provides other advantages over interior water heaters. For example, the design of interior water heaters must account for such considerations as flooding, CO generation, interior noise, some fire hazards arising from flammable vapors, building depressurization, and exhaust venting. While interior water heaters are sometimes limited to a significant degree by such design concerns, a rooftop water heater embodying the present invention is typically not affected to the same extent. This may make design and maintenance of the rooftop water heater simpler and cheaper in some instances when compared to the design and maintenance of interior water heaters.
[0006] Several design parameters are imposed on the design of a rooftop water heater by weather conditions and the expectations of potential purchasers of such water heaters. The water heater must first account for weather conditions not normally encountered by interior water heaters. It would be desirable to mount the water heater on a weather-tight roof curb that would support the water heater above expected water levels in the event of a roof flood. The roof curb would also provide the required weight load distribution to the roof. Because roof curbs are already used to support other rooftop equipment, it is convenient to use a roof curb to support a rooftop water heater as well.
[0007] To maintain the aesthetics of their buildings, purchasers would likely want equipment that cannot be ordinarily seen from the ground level. The water heater therefore must have a sufficiently low profile and be of substantially the same height as most HVAC equipment to meet the expected demands of purchasers.
[0008] In light of the foregoing considerations, the present invention provides a rooftop water heater that includes a water tank mounted on a base member which is in turn mounted on a roof curb. The base member includes a drain communicating with the building's sewage system so that water leaking or otherwise flowing out of the water tank is drained away from the water heater without causing damage to the roof or the water heater itself. A pair of rails may be mounted under the base member such that the water heater and base member may be moved with a fork lift. The rails also include holes for accepting the hooks of a lifting crane for raising the water heater to the roof of the building.
[0009] The water tank is preferably generally cylindrical in shape with a longitudinal axis extending substantially horizontally. In this regard, the tank has a low profile compared to a tank having its longitudinal axis extending vertically. A head encloses one end of the tank. A plurality of water pipes extend up through the roof curb and through a water pipe aperture in the base member. A vertical wall surrounds the water pipe aperture. A grommet fits over the vertical wall and seals the water pipes with respect to the base member.
[0010] A plurality of panels, including a cabinet door and a top, are preferably interconnected with and supported by the base member to substantially weather-tightly enclose the water tank. The top and cabinet door may be removed from the other panels to permit access to the water tank.
[0011] A U-shaped flue tube is preferably contained within the water tank. A baffle or turbulator is positioned within one of the legs of the U-shaped flue tube. The ends of the flue tube extend through the head of the tank. The legs each include a longitudinal axis, and the longitudinal axes together define a flue plane that may be disposed substantially vertically, or may be angled with respect to vertical. Preferably, the flue plane is angled in the range of 30-60° with respect to vertical.
[0012] The water heater also includes inlet and outlet tubes for providing cold water to the tank and drawing hot water from the tank, respectively. The inlet and outlet tubes extend substantially the entire inside length of the tank, and preferably include a plurality of apertures facing in a single direction. The outlet tube is positioned in the top portion of the tank with its apertures facing up while the inlet tube is positioned in the bottom portion of the tank with its apertures facing down. Preferably, the inlet and outlet tubes extend through the head of the tank, but in an alternative construction, the inlet and outlet tubes include elbows that extend through the tank shell.
[0013] Other features and advantages of the invention will become apparent to those skilled in the art upon review of the following detailed description, claims, and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] [0014]FIG. 1 is a perspective view of a water heater embodying the present invention.
[0015] [0015]FIG. 2 is a view of the water heater of FIG. 1 from a different perspective.
[0016] [0016]FIG. 3 is an exploded view of the cabinet of the water heater of FIG. 1.
[0017] [0017]FIG. 4 is a perspective view of the tank assembly of the water heater of FIG. 1.
[0018] [0018]FIG. 5 is a schematic illustration of the piping system associated with the tank assembly of FIG. 4.
[0019] [0019]FIG. 6 is a cross-section view taken along line 6 - 6 in FIG. 4.
[0020] [0020]FIG. 7 is a perspective view of the tank assembly of FIG. 4 with selected elements removed for the purpose of illustration.
[0021] [0021]FIG. 8 is an exploded view of the tank assembly of FIGS. 4 and 7.
[0022] [0022]FIG. 9 is an end view of the tank assembly of FIGS. 4 and 7.
[0023] [0023]FIG. 10 is a side cross-section view of the tank assembly taken along line 10 - 10 in FIG. 9.
[0024] [0024]FIG. 11 is a view of the outlet tube taken along line 11 - 11 in FIG. 10.
[0025] [0025]FIG. 12 is an end view of a tank assembly of an alternative construction.
[0026] [0026]FIG. 13 is a side cross-section view taken along line 13 - 13 in FIG. 12.
[0027] Before one embodiment of the invention is explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or being carried out in various ways. Also, it is understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including” and “comprising” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. The use of “consisting of” and variations thereof herein is meant to encompass only the items listed thereafter. The use of letters to identify elements of a method or process is simply for identification and is not meant to indicate that the elements should be performed in a particular order.
DETAILED DESCRIPTION
[0028] The present invention is embodied in a water heater including a cabinet 10 illustrated in FIGS. 1 - 3 and a tank assembly 14 illustrated in FIGS. 4 - 13 . A first construction of the tank assembly 14 is illustrated in FIGS. 4 - 11 . With particular reference to FIGS. 9 and 10, the tank assembly 14 includes a tank 18 having a substantially cylindrical shape and a horizontally-extending longitudinal axis 22 . The tank 18 includes a shell 24 that is closed at one end by a head 26 . A U-shaped flue tube 30 is positioned within the tank 18 . The U-shaped flue tube 30 includes two legs 31 , 32 communicating through a curved or bent portion 33 . The legs 31 , 32 terminate in a burner end 34 and an exhaust end 38 , respectively, both of which extend through the head 26 .
[0029] Turning to FIGS. 1 - 3 , the cabinet 10 is mounted on a roof curb 42 on a rooftop 46 of a building, and encloses the tank assembly 14 . The cabinet 10 is generally rectangular in shape, having its major axis extending generally horizontally. In this regard, the cabinet 10 has a generally low profile and is similar to other rooftop units such as typical HVAC (e.g., air conditioning) units. As used herein, “low profile” means that the rooftop water heater cabinet 10 cannot typically be seen by a person of average height standing at ground level from a distance of about one city block. The low profile therefore permits the unit to be mounted on a rooftop without detracting from the aesthetics of the building. Roof rails and a pitch pocket or small roof curb may be used as an alternative mounting structure to the roof curb 42 illustrated.
[0030] As seen in FIG. 3, the cabinet 10 includes two side panels 50 , 54 arranged generally parallel to each other and at right angles to a third side panel or end panel 58 . A second end panel or cabinet door 62 is releasably attached at right angles to the two side panels 50 , 54 and generally parallel to the end panel 58 . The door 62 includes a cutout 66 and a recessed or raised handle 70 to facilitate removal of the door 62 from the rest of the cabinet 10 without the use of tools. An upper panel or top 74 is releasably affixed to the top edges of the other panels 50 , 54 , 58 , 62 of the cabinet 10 . The top 74 is preferably removable from the rest of the cabinet 10 without the use of tools. Preferably the door 62 and top 74 are locked to the other panels 50 , 54 , 58 to resist tampering with the tank assembly 14 .
[0031] A base member 78 supports the cabinet panels 50 , 54 , 58 , 62 , 74 and provides the bottom of the cabinet 10 . The base member 78 is supported by the roof curb 42 , and a foam tape or other sealing member is preferably interposed between the roof curb 42 and the base member 78 to create a water-tight seal therebetween. A pair of rails 82 are mounted to the underside of the base member 78 and straddle the roof curb 42 . The rails 82 define channels along their lengths into which the prongs of a conventional fork lift may be inserted for lifting and lowering the water heater, and also include slots 86 to insert the forklift prongs transverse to the channels. The rails 82 also include apertures 90 for attaching the hooks of a lifting crane to facilitate lifting the water heater to the roof 46 of the building.
[0032] When the top and door 74 , 62 are removed, the tank assembly 14 is sufficiently exposed to permit a service technician to perform service on the water heater. An electrical disconnect button 94 (FIG. 1) is mounted to one of the side panels 50 . The disconnect button 94 permits the service technician to conveniently connect and disconnect power to the water heater while the technician is on the rooftop 46 . An electrical outlet 98 (FIG. 1) is also provided to accommodate a service technician's power tools and electric lights. Another feature of the water heater is the provision of local and remote controllers 99 , 100 , respectively, that include thermostats. The local controller 99 may be mounted on the side panel 50 as illustrated, or it may be mounted within the cabinet 10 . The remote controller 100 is mounted in a desirable place within the building. The local and remote controllers 99 , 100 each include a digital display of the water temperature within the tank 18 , and permit adjustment of the temperature. Thus, the water heater may be monitored and controlled from both the rooftop 46 and from within the building. This arrangement creates convenience for both the building owner or occupant within the building and a service technician on the rooftop 46 .
[0033] The cabinet panels 50 , 54 , 58 , 62 , 74 are joined together around the tank assembly 14 in a weather-tight fashion. As used herein, “weather-tight” means that rain or other precipitation falling on the cabinet 10 from above are substantially prevented from entering the cabinet 10 and interfering with the operation of the water heater. For example, one of the side panels 54 includes an air inlet vent 102 that opens downwardly to cause precipitation to run off the cabinet 10 , and the other side panel 50 includes a downwardly-opening exhaust vent 106 . In addition to being weather-tight, the edges of the cabinet panels 50 , 54 , 58 , 62 , 74 are preferably substantially water-tightly joined to each other (e.g., by welding or with gasket material) to resist or prevent water from entering the cabinet 10 and interfering with the operation of the water heater.
[0034] Turning now to FIG. 4, the tank assembly 14 will be discussed in more detail. A fan or combustion blower 110 communicates with the air inlet vent 102 through an inlet duct 112 to deliver air from outside the cabinet 10 to a gas fuel burner 114 positioned at the burner end 34 of the flue tube 30 . Gas fuel is also delivered to the burner 114 via a gas pipe 118 and regulator 122 . The burner 114 causes combustion of the air and gas fuel, and the products of combustion are forced through the flue tube 30 by the combustion blower 110 . The products of combustion heat the water in the tank 18 through the wall of the flue tube 30 , and then exit the exhaust end 38 of the flue tube 30 . The exhaust vent 106 communicates with the exhaust end 38 of the flue tube 30 through an exhaust duct 123 to permit the spent products of combustion to be exhausted to the surrounding atmosphere.
[0035] With additional reference to FIG. 8, a baffle or turbulator 124 is positioned within one of the legs 31 , 32 of the U-shaped flue tube 30 , and preferably in the upper leg 32 . The legs 31 , 32 each include a longitudinal axis 125 (FIG. 10), and the longitudinal axes 125 together define a flue plane FP (FIG. 9) that may be disposed substantially vertically, or may be angled with respect to vertical an angle labeled α. Preferably, the angle α is between 30-60° with respect to vertical.
[0036] Referring to FIGS. 8 - 11 , an inlet tube 126 and outlet tube 130 are also mounted in the head 26 , and extend substantially parallel to the longitudinal axis 22 of the tank 18 . The inlet tube 126 is positioned in the bottom portion of the tank 18 below the longitudinal axis 22 , and the outlet tube 130 is positioned in the top portion of the tank 18 above the longitudinal axis 22 . Preferably, the inlet tube 126 , outlet tube 130 , and longitudinal axis 22 of the tank 18 are aligned parallel to each other in a vertical plane. This arrangement is made possible in part because the flue plane angle α is greater than zero (i.e., the flue plane FP is non-vertical), which moves the legs 31 , 32 of the flue tube 30 from a position in which they would interfere with the extension of the inlet and outlet tubes 126 , 130 . The tubes 126 , 130 are substantially identical to each other and preferably have a length 132 (FIG. 11) slightly shorter than or substantially the same as the interior length 134 of the tank 18 so that cold water is provided and hot water is removed along the entire interior length 134 of the tank 18 . The preferred length 132 is between about 37 and 38 inches, but the length 132 will vary depending on the dimensions of the water tank 18 . A threaded end 138 is attached at one end of the tubes 126 , 130 . The threaded end 138 is threaded into a threaded spud 142 in the tank head 26 , and includes additional threads to receive a nipple, water pipe, or other plumbing fixture. In a less preferred embodiment, one or both of the tubes 126 , 130 may be significantly shorter than illustrated, or the outlet tube 130 may be removed, leaving only the conventional spud 142 to which the building's hot water pipe communicates.
[0037] The end 146 opposite the threaded end 138 is closed. The tubes 126 , 130 include a plurality of holes, apertures, or openings 150 along their lengths. The tubes 126 , 130 preferably have an outer diameter of about one inch, with the holes 150 having a diameter of about 0.25 inches. The hole spacing 154 is preferably about five inches, with the last hole being spaced from the closed end 146 a distance 158 of about 0.5 inches.
[0038] In the illustrated construction, all of the openings 150 in the inlet tube 126 face down and all of the openings 150 in the outlet tube 130 face up. Thus, the inlet tube 126 directs cold water toward the bottom of the tank 18 and the outlet tube 130 draws hot water from the top of the tank 18 . This is advantageous because the hottest possible water is drawn from the top by the outlet tube 130 while the inlet tube 126 introduces cold water directly at the bottom of the tank 18 . The inlet tube 126 therefore evenly distributes water at the bottom of the tank to minimize mixing and thereby maximize heated water drawn from the tank 18 . In alternative less preferred constructions, the openings 150 may be arranged around the periphery of the tubes 126 , 130 instead of opening in only one direction.
[0039] As can be seen in FIGS. 3, 4, and 6 , the base member 78 includes a water pipe aperture 162 surrounded by a vertical wall 166 . Four water pipes 168 a , 168 b , 168 c , 168 d (collectively referred to as 168 ) extend up from the building, through the roof curb 42 , and through the aperture 162 , and communicate with the water tank 18 . A grommet 170 includes apertures 174 water-tightly slip fit around the water pipes 168 , and has a depending wall 178 (FIG. 6) water-tightly slip fit over the vertical wall 166 . The grommet 170 therefore provides a water-tight seal between the pipes 168 and the base member 78 . Suitable clamps 182 can be employed to further tighten the grommet 170 around the vertical wall 166 and pipes 168 .
[0040] FIGS. 4 - 6 illustrate the piping system associated with the tank assembly 14 . One of the water pipes 168 a provides cold water to the water inlet tube 126 . Another water pipe 168 b removes hot water from the tank 18 through the outlet tube 130 , and this hot water is used for dishwashers and other applications requiring very hot water (e.g., between about 120° F. and about 150° F., or a higher temperature if necessary). Another water pipe 168 c communicates with a mixing valve 186 , and delivers a mixture of hot water and cold water to the warm water faucet of the building's bathrooms and kitchen sink.
[0041] The last water pipe 168 d communicates between the building's hot water pipes and a circulation pump 190 . The circulation pump 190 performs two functions. First, the circulation pump 190 is turned on by the controller 99 (FIG. 1) each time the combustion blower 110 is turned on, and remains active for a set period of time (e.g., about nine minutes) after the combustion blower 110 is turned off. A bypass valve 191 is actuated to route water from the outlet tube 130 , through the circulation pump 190 , and back into the tank 18 through the inlet tube 126 . In this manner, the circulation pump 190 causes hot water to be drawn off the top of the water tank 18 through the outlet tube 130 and recirculated through the cold inlet tube 126 to even out the temperature of the water in the tank 18 and reduce the effects of stacking.
[0042] The second function of the circulation pump 190 is to maintain a supply of hot water in the pipes of the building. A thermostat 192 (FIG. 5) may be employed to determine when the temperature in the building's hot water pipes has dropped below an desired temperature (e.g., when a hot water draw has not occurred for an extended period of time). In this case, the bypass valve 191 is turned to permit the circulating pump 190 to circulate the water in the building's hot water pipes into the inlet pipe 126 , which forces hot water out the outlet pipe 130 and into pipe 168 b . The hot water replaces the water in the building's hot water pipes. The piping system also includes check valves CV and an adjustable gate valve GV (which may be replaced with a fixed valve). The gate valve GV may be used to control the flow rate of recirculated water into and out of the water tank 18 . Referring again to FIG. 3, the base member 78 also includes a drain opening 194 that receives a drain member 198 . The drain member 198 communicates with a drain pipe 202 (shown in phantom in FIGS. 1, 2, and 4 ) in the building, and the drain pipe 202 communicates with the building's sewage system. The drain opening 194 is the only opening in the base member 78 through which water is permitted to flow in the event of a water leak within the cabinet 10 . Thus, any water flowing freely within the cabinet 10 drains through the drain opening 194 and is routed to the building's sewage. The tank assembly 14 also includes a drain valve 204 (FIG. 5) that permits the tank 18 to be drained. The valve 204 is preferably positioned over the drain opening 194 .
[0043] As seen in FIGS. 4 and 8, the water heater also includes a temperature and pressure valve 206 , which opens in the event the temperature of the water in the tank 18 becomes too high, or if unacceptable pressure levels are present within the tank 18 . A hose or pipe 210 extends down from the temperature and pressure valve 206 , and terminates above the drain opening 194 . Water is drained from the top of the tank 18 and is fed into the building's sewage system in the event of an overtemperature or overpressure condition in the tank 18 .
[0044] Referring again to FIGS. 7 and 8, the water tank assembly 14 also includes a pair of support rails 214 extending transverse to the longitudinal axis 22 of the tank 18 , and a pair of wedge-shaped supports 218 welded or otherwise affixed to each support rail 214 . Tank mounting brackets 222 are attached (e.g., welded) to the tank 18 , and a thermally insulated spacer 226 is interposed between the tank mounting brackets 222 and the wedge-shaped supports 218 . Suitable fasteners couple the supports 218 to the brackets 222 . The tank 18 is surrounded with insulation 230 to reduce heat loss from the tank 18 to the ambient air. The head 26 includes an access opening 234 for cleaning the tank 18 and for applying a glass coating to the inside of the tank 18 during manufacture. An access cover 238 is mounted over the opening 234 and a gasket 242 is employed to prevent leakage of water through the access opening 234 . A thermostat and/or an anode tube are mounted in spuds 246 in the access cover 238 .
[0045] An alternative construction of the tank assembly 14 is illustrated in FIGS. 12 and 13. Here the flue plane FP is substantially vertical, and alternative inlet and outlet tubes 254 , 258 , respectively, are positioned below and above, respectively, the flue tube 30 . A 90° elbow 262 is provided on both the inlet and outlet tube 254 , 258 so that the tubes communicate with the building's pipes through the cylindrical shell 24 of the tank 18 and through the insulation 230 , rather than through the head 26 .
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A method and apparatus for mounting a water heater on the roof of a building or at another location outside of the building. A roof curb surrounds a hole in the roof, and a base member is mounted to the roof curb. Alternatively, the base member is mounted on a concrete pad at ground level. A water tank is mounted to the base member with the longitudinal axis of the water tank extending horizontally. Support rails are mounted to the base member, and wedge-shaped supports are mounted to the support rails. The wedge-shaped supports are interconnected with tank mounted brackets that are mounted to the sides of the water tank. Thermally insulated spacers are interposed between the wedge-shaped supports and the tank mounting brackets.
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BACKGROUND OF THE INVENTION
The present invention relates to a filter assembly machine.
More specifically, the present invention relates to a filter assembly machine wherein filters are connected to cigarette portions by means of gummed strips of paper material, each of which is rolled about a respective tobacco article defined by two cigarette portions aligned axially with the interposition of a filter twice the length of a finished cigarette filter.
Such strips are rolled about the tobacco articles by means of a so-called rolling operation performed by feeding the articles and respective strips, by means of a conveyor drum, along a rolling channel of a width approximately equal to but no wider than the diameter of the articles. The channel is normally defined by a fixed plate facing the periphery of the conveyor drum, and which provides for frictionally rolling the articles backwards onto the respective gummed strips to form double cigarettes.
During the rolling operation, the double cigarettes being formed are rolled as described above at a speed which may only assume one value for each operating speed of the machine, and which, over and above a given value, inevitably results in tobacco fallout from the open ends of the cigarette portions.
By way of a solution to the problem, U.S. Pat. No. 4,848,371 relates to a filter assembly machine featuring a rolling station comprising a multiple-rolling wheel for transferring and rolling the articles between a supply drum and an output drum. The rolling wheel comprises a cylindrical body with a number of equally spaced peripheral cavities, each housing a revolving roller defining, with the respective cavity, a curved rolling channel of a width approximately equal to but no wider than the diameter of the article. Each roller has two diametrically opposite suction seats, into one of which an article is fed from the supply roller. As the roller rotates, the article, on abandoning the respective seat, travels at least once along the rolling channel, is wrapped inside the respective strip to form a double cigarette, and, each time it comes out of the rolling channel, is fed into the opposite seat. Each double cigarette is then transferred to the output drum.
While indeed enabling the articles to be rolled at a speed slower than that at which they are transferred between the supply and output drums, the above known filter assembly machine involves several drawbacks, due to the impossibility of using rollers of less than a given minimum diameter, without impairing the rolling operation or complicating the construction design of the rolling wheel.
On the other hand, small-diameter rollers would enable a reduction in the spacing of the rollers, and hence of the articles, on the rolling wheel, and an increase in the output of the machine for a given traveling speed.
The preference on known multiple-rolling filter assembly machines is to employ fairly large-diameter rollers, and subsequently reduce the spacing of the double cigarettes to avoid feeding them at too high a speed. Such a reduction, however, has been found to have a tendency to damage the double cigarettes, and is therefore to be avoided.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a filter assembly machine designed to overcome the aforementioned drawbacks.
According to the present invention, there is provided a filter assembly machine comprising a supply drum for supplying articles and gummed strips, each article comprising at least one cigarette portion and a filter aligned with and adjacent to each other; a rolling unit for winding a respective gummed strip about each cigarette portion and respective filter; and an output drum for successively evacuating the rolled articles; said rolling unit comprising a rolling wheel rotating about an axis and having a number of peripheral axial cavities, and a roller housed inside each cavity and defining, with the cavity, a rolling channel; each roller having a first seat for receiving a respective article from the supply drum and feeding said article to the rolling channel, and a second seat for withdrawing the article from the rolling channel; said machine being characterized in that the rolling unit comprises a first and a second said rolling wheel rotating in the same direction about respective axes; conveying means being provided to transfer the articles from the second seats of the first and the second rolling wheel to the output drum; and said conveying means having third seats located at the end of respective ribs, each of which is engaged between a respective pair of adjacent said rollers.
Using two rolling wheels, as opposed to one, has the advantage, on the one hand, of ensuring fairly high production despite feeding the articles, during the rolling operation, at fairly low speed along the respective rolling channels, but, on the other hand, has the disadvantage of having to transfer the articles successively to a single output drum by means of fairly cumbersome transfer means.
According to a preferred embodiment of the present invention, said conveying means comprise a first and a second transfer drum rotating in the same direction about respective axes, and for respectively transferring said articles from the first and second wheel to the output drum.
In the machine according to the preferred embodiment described above, the above drawback is substantially negligible, in that, unlike the machine described in U.S. Pat. No. 4,848,371--wherein each article is only unloaded off the rolling wheel upon the rolled article reaching the furthest point from the axis of the rolling wheel--the preferred embodiment described above, by featuring two transfer drums with ribs engageable between the rollers, provides for withdrawing each article at any point along an arc extending about the axis of the relative roller and complementary to the arc along which the relative rolling channel extends. As such, withdrawal points may be so selected as to position the two transfer drums close together and so select the best configuration in terms of size.
BRIEF DESCRIPTION OF THE DRAWING
The present invention will now be described by way of a non-limiting example with reference to the accompanying drawing, which shows a front view, with parts removed for clarity, of a preferred embodiment of the filter assembly machine according to the invention.
DETAILED DESCRIPTION OF THE INVENTION
Number 1 in the accompanying drawing indicates as a whole a filter assembly machine for producing filter-tipped cigarettes.
Machine 1 comprises a rolling unit 2; a supply drum 3 located upstream from unit 2; and an output drum 4 located downstream from unit 2 in a direction D. Supply drum 3 rotates anticlockwise about an axis 5 of rotation, and comprises a succession of seats 7 parallel to axis 5 and equally spaced with a spacing "L" about the periphery of drum 3. Each seat 7 provides for retaining a respective article 8 comprising, in known manner, two cigarette portions (not shown) aligned with each other at opposite ends of a double filter (not shown), i.e. a filter twice the length of a finished cigarette filter.
Articles 8 are fed in known manner to seats 7 together with respective gummed strips 9, each of which is positioned with one end resting on a mid portion of the outer periphery of respective article 8, and with the other end resting on a suction retaining element 10 located on the periphery of drum 3, downstream from each seat 7 with reference to the rotation direction of drum 3. Articles 8 and strips 9 are therefore fed to rolling unit 2 in an orderly stream, and in a succession with spacing "L", along a path "P1" defined by seats 7.
Output drum 4 rotates clockwise about an axis 11 of rotation parallel to axis 5, and comprises a succession of seats 13 parallel to axis 11 and about the periphery of drum 4. Seats 13 define a path "P2", and provide for retaining respective articles 8, each applied with a respective gummed strip 9.
Unit 2 comprises two identical rolling wheels 14 and 15, both rotating clockwise about respective axes 16 and 17 parallel to axis 5. Each wheel 14, 15 receives half the orderly stream supplied by drum 3, and comprises a cylindrical body 18 fitted integrally with a substantially cylindrical conveying and rolling element 19 coaxial with axis 16, 17. Element 19 has a number of axial peripheral cavities 20, each in the form of a cylindrical sector of angle "a" and positioned with its concavity facing outwards of element 19.
Each cavity 20 is engaged by a roller 22 coaxial with cavity 20 and fitted to cylindrical body 18 to rotate about a respective axis 21 parallel to axes 16 and 17. Each roller 22 has two axial suction seats 23 and 24 located at two diametrically-opposite portions of the peripheral surface of the roller, and for receiving and retaining an article 8. The surface of each roller 22 and the surface of each cavity 20 are knurled, and the diameter of each roller 22 is such that, between roller 22 and respective cavity 20, there is defined a passage 25--hereinafter referred to as a "rolling channel"--extending along an arc subtended by an angle equal to angle "a". Rolling channel 25 is of constant width approximately equal to but no wider than the diameter of article 8.
Each roller 22 is connected in known manner to body 18 to rotate clockwise, in the accompanying drawing, about respective axis 21 by means of a known gear train (not shown), the gear ratio "i" of which is such that each complete turn of body 18 corresponds to three complete turns of each roller 22 about respective axis 21, and, for each complete turn, seats 23 and 24 return to their original positions. The combined rotation of wheel 14, 15 and rollers 22 imparts to seats 23 and 24 a precession about axis 16, 17, so that seats 23 and 24 define respective cycloidal paths "P3" and "P4" in phase opposition to each other, and, when a seat 23 is at the maximum distance from axis 16, 17 of wheel 14, 15, the corresponding seat 24 is at the minimum distance from axis 16, 17 and vice versa.
Cycloidal path "P3" of wheel 14 is substantially tangent to path "P1" of drum 3 at a point "H", and seats 23 of rollers 22 of wheel 14 are synchronized with respective seats 7 equally spaced about drum 3 with a spacing equal to twice spacing "L". Similarly, cycloidal path "P3" of wheel 15 is substantially tangent to path "P1" at a point "K", and seats 23 of wheel 15 are synchronized with respective seats 7 equally spaced about supply drum 3 with a spacing equal to twice spacing "L", and which are offset by spacing "L" with respect to the seats 7 synchronized with seats 23 of wheel 14, so as to divide the stream of articles 8 supplied by drum 3 into two equal half-streams fed respectively to wheel 14 and wheel 15.
Each article 8 is fed by respective seat 23 into channel 25, in which article 8 leaves seat 23 and rolls between the surface of respective cavity 20 and the surface of respective roller 22. At the output of channel 25, article 8 engages respective seat 24 and so switches from path "P3" to path "P4".
Filter assembly machine 1 also comprises a transfer unit 26 between rolling unit 2 and output drum 4. Unit 26 comprises a transfer drum 27 for transferring articles 8 from wheel 14 to drum 4; and a drum 28 for similarly transferring articles 8 from wheel 15 to drum 4. Each drum 27, 28 rotates anticlockwise about a respective axis 29, 30 parallel to axes 16 and 17, and comprises a succession of axial ribs 31 equally spaced about the outer surface of drum 27, 28 with a spacing, at the free ends, substantially equal to that of rollers 22 about axis 16, 17, and sloping backwards with respect to the direction of rotation of drum 27, 28. The free end of each rib 31 has a respective suction seat 32 for retaining a respective article 8, and which, as it travels about respective axis 29, 30, defines a respective path "P5", "P6" for the rolled articles 8.
Drum 27 is so positioned that path "P5" is tangent to path "P4" of wheel 14 at a transfer point "F", which in turn is so located that a plane 33 through point "H" and axis 16 of wheel 14 forms, with a plane 34 through point "F" and axis 16 of wheel 14, and in the rotation direction of wheel 14, an angle 37 of less than 180°, i.e. that articles 8 are transferred from wheel 14 to drum 27 before seat 24 reaches the maximum distance from axis 16.
Drum 28 is so positioned that path "P6" is tangent to path "P4" of wheel 15 at a transfer point "G", which in turn is so located that a plane 35 through point "K" and axis 17 of wheel 15 forms, with a plane 36 through point "G" and axis 17 of wheel 15, and in the rotation direction of wheel 15, a second angle 38 of over 180°, i.e. that articles 8 are transferred from wheel 15 to drum 28 after seat 24 passes the maximum distance from axis 17.
Paths "P5" and "P6" are tangent to path "P2" of output drum 4 at respective transfer points "R" and "T", and seats 32 of drums 27 and 28 are synchronized with respective seats 13 of drum 4 so as to form said two half-streams once more into one stream.
In actual use, articles 8 and strips 9 are conveyed by drum 3 in one stream and in an orderly succession, and are fed onto wheels 14 and 15, each of which provides, as clearly understandable from the foregoing description, for rolling the articles as a respective half-stream of articles 8 is fed between points "H" and "F", "K" and "G".
Articles 8 are transferred from wheel 14, 15 to respective drum 27, 28 along a portion 39 of respective path "P4" about respective axis 16, 17, which portion is subtended by an angle "B" defined by the formula:
B=(360°-a)/i
where "a" is the angle of the sector defining cavity 20, and "i" is the gear ratio between rollers 22 and wheel 14, 15.
The transfer of articles 8 along portion 39 is made possible by ribs 31, each of which provides for inserting a respective seat 32 inside the gap between a respective pair of adjacent rollers 22, and for withdrawing article 8 both before and after respective seat 24 reaches the maximum distance from axis 16, 17.
This is particularly advantageous, as compared with withdrawing articles 8 from seats 24 at a maximum distance from axis 16, 17, by enabling drums 27 and 28 to be so located as to reduce the size of drums 27 and 28.
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A filter assembly machine wherein a succession of tobacco articles, each defined by at least one cigarette portion aligned with a respective filter, and a succession of respective gummed strips are fed by a conveyor drum to a first and a second rolling wheel rotating about respective axes and having a number of peripheral axial cavities, each of which houses a respective roller defining, with the cavity, a rolling channel; the tobacco articles, once rolled to connect the cigarette portions and filters by means of respective strips, are transferred from the first and second rolling wheel to an output drum by means of conveyors having seats on the end of respective ribs engageable between pairs of adjacent rollers.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention pertains to decorative displays, and more specifically to decorative displays incorporating moving elements. Most particularly, the present invention pertains to decorative displays of the aforementioned type particularly suited for use as Christmas displays.
2. Background Art
A wide variety of ornamental displays incorporating moving elements exist. For example, U.S. Pat. No. 4,708,685 (Udagawa) discloses such a display comprising an inclined track having a first raised end and a second end therebeneath, with a lifting means disposed between the two ends. The lifting means transports a plurality of moving figurines from the second end of the track to the first end whereupon the figurines, which are mounted on rollers, traverse the track from the first end to the second end, and so on. A drawback to the Udagawa device is that it is capable of operation only when supported on a relatively flat surface, such as a ground surface or a table top. The devices disclosed in U.S. Pat. Nos. 4,678,449 and 4,609,363 suffer similar drawbacks.
It is, therefore, an object the present invention to provide a display which is capable of operation while suspended above a ground surface. In particular, it is an object of the present invention to provide a Christmas display, incorporating moving elements, for use in conjunction with a Christmas tree, thereby creating a visually pleasing effect.
Another object of the present invention is to provide a Christmas display, incorporating moving elements and a track upon which the moving elements traverse, for use in conjunction with a Christmas tree, comprising a mechanism for positioning the track about the tree and above a ground surface.
It is a further object of the present invention to provide a Christmas display of the aforementioned type which simulates a ski-lift and a ski-slope, and which incorporates lifting means for lifting a plurality of figurines from one end of the ski-slope to the other whereupon the figurines traverse the ski-slope, thereby creating an "action" scene.
It is still a further object of the invention to provide means for optionally supporting the display on a ground surface.
SUMMARY OF THE INVENTION
The present invention is a display for use in combination with a Christmas tree, extending vertically upward from a ground surface. Broadly speaking, the present invention comprises a track having first and second ends with the first end being at a higher elevation than the second end, at least one figurine having a bottom surface portion configured for slidable movement along the track between the first and second ends, means for lifting the figurine from the second end of the track to the first end thereof for providing continuous traversal of the figurine along the track, and means for securing the track about the Christmas tree for supporting the track above the ground surface.
In the preferred embodiment, the display comprises attachable legs for supporting the track when the lift is optionally positioned on a flat surface.
The foregoing as well as additional details of the present invention will be more fully apparent from the following detailed description and annexed drawings of the presently preferred embodiments thereof.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings:
FIG. 1 is a perspective view showing the preferred display of the present invention supported on a Christmas tree;
FIG. 2 is a cross-sectional view of the lift mechanism of the display of FIG. 1;
FIG. 3 is a cross-sectional view of the upper portion of the lift mechanism showing a figurine coupled thereto;
FIG. 4 is a fragmentary perspective view of the lift mechanism showing a figurine coupled thereto;
FIG. 5 is a top plan view of the preferred display shown in FIG. 1;
FIGS. 6A-C are fragmentary views of the means for coupling the track sections in the preferred display;
FIG. 7 is a fragmentary perspective view illustrating the connection between the support spokes and the track in the preferred display;
FIG. 8 is a perspective view of the collar for supporting the preferred display about the trunk of a Christmas tree;
FIG. 9 is a partially exploded perspective view of the collar of FIG. 8 showing the manner in which the support spokes and support beam are coupled thereto;
FIGS. 10A-B are fragmentary elevational views further illustrating the means for coupling the support spokes to the collar;
FIG. 11 is a fragmentary perspective view showing the connection between the support beam and the lift;
FIG. 12 is a perspective view of another embodiment of the present invention; and
FIG. 13 is a perspective view of still another embodiment of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the drawings and initially to FIG. 1, the display in accordance with the present invention is generally designated at 10. As shown, the display includes a curved track 12 having a first end 14 and a second end 16 with a lift 18, having a top 20 and bottom 22, disposed therebetween. The first end 14 of the track 12 is attached to the top 20 of the lift 18 and the second end 16 of the track is attached to the bottom 22 of the lift, such that the first end of the track is at a higher elevation than the second end. As shown, the track 12 has a continuous downward slope from its first end 14 to its second end 16.
Referring now to FIGS. 1-4, the display 10 includes at least one figurine 30 for traversing track 12. In the preferred embodiment, display 10 includes a plurality of Christmas theme figurines 30, such as a family on a sled or, as shown in FIG. 1, Santa Claus. As shown, figurine 30 has a base 32 comprising two substantially parallel spaced apart members 34 simulating skis, the front of the members 34 being connected by a cross-member 36. Two rollers 36 are mounted between the members 34 and aligned for facilitating traversal of track 12 by figurine 30.
Lift 18 comprises a housing 40 supporting a decorative hut 42 having a base 44, and two spaced apart pulleys 46, 48, one positioned at the bottom 22 of lift 18 and the other positioned at the top 20. The hut 42 has two pegs (not shown) on its base 44 for snap-fitting into peg holes (not shown) on the top 20 of lift 18, thereby securing hut 42 to the top 20 of lift 18. The lift 18 also comprises an AC motor (not shown) for driving one of the pulleys 46, 48 in a manner well known to those of ordinary skill in the art. An endless belt 50 is positioned around pulleys 46, 48 for rotation thereabout when the motor is activated, also in a manner well known to those of ordinary skill in the art. The outer surface 52 of belt 50 has a plurality of spaced apart pins 56 oriented normal to the surface 52 and integrally formed therewith. Each pin 56 has a hooked end 58 for facilitating the seating of cross-member 36 and ensuring that the figurine 30 remains secured to endless belt 50 during lifting, as more fully explained below. Lift 18 also includes a receiving slot 1 19 and, as best shown in FIG. 4, an upper surface portion configured as a bifurcated ramp 60 having a slot 62. As more fully explained below, the ramp 60 overlies the endless belt 50 such that the hooked ends 58 of the pins 56 protrude through slot 62.
The AC motor is preferably powered by an external power cord (not shown) which connects lift 18 to a standard 120 v, 60 Hz electrical outlet. As is known to those of ordinary skill in the art, an on/off switch may be employed to supply or cut power to the motor or, in the alternative, the motor may be powered by batteries. When power is supplied, the A-C motor moves endless belt 50 in the direction shown by the arrows in FIG. 2 for transporting the figurine 30 from the bottom 22 of the lift 18 to the top 20 as one of the hooked ends 58 engages cross-member 36.
Referring now to FIGS. 5-7, track 12 comprises a plurality of interlocking straight and curved track sections 64, each having a first end 66, a second end 68 and parallel sidewalls 84, the latter serving to maintain the figurine 30 on the track 12 as it traverses same. The first end 66 of each section 64 has a generally "V"-shaped portion comprising a pair of protrusions 70, 72, each protrusion having a flared end 74. The second end 68 of each track section 64 has a pair of spaced apart channels 76, 78 spaced apart by a distance slightly less than the distance between the flared ends 74 of protrusions 70, 72. Each channel 76, 78 has an outer wall 80 having a length shorter than the length of the "V"-shaped portion. As should by now be apparent, track sections 64 are assembled to form track 12 by squeezing protrusions 70, 72 together and inserting them into channels 76, 78. As best shown in FIG. 6C, when this is done, the flared ends 74 slide along walls 80 until they reach the ends thereof, whereupon the flared ends spring apart and hook about the distal ends of the outer walls 80, thereby securing the track sections 64 together.
The configuration of the track 12 may be altered by adding or removing track sections 64, provided, of course, that track 12 begins at the top end 20 of lift 18 and terminates at the bottom end 22. In the preferred embodiment, and as shown in FIG. 6A, the first end 66 of each track section 64 has a tab 82 embossed with a designation for assisting the user in assembling the track 12 in a predetermined configuration. As shown in FIG. 7, the undersides of some track sections 64 include posts 85 having axial bores 86 for securing track 12 to support spokes 106, 108, 110 as more fully explained below. Preferably, the upper surfaces of at least some track sections 64 also included peg holes (not shown) for mounting stationary decorative ornaments such as flags 62, as shown in FIG. 1.
Referring now to FIGS. 1-5, 8-9, the preferred display 10 includes a collar 90 for supporting the display above the ground about a vertical support member, such as the trunk 94 of a Christmas tree 92. As best seen in FIGS. 8 and 9, collar 90 comprises two "U-shaped" sections 120, 122 each having two free ends and an upper surface defining a lip 124. As shown, each free end of section 120 has a pair of alignment protrusions 126, 128, each protrusion having a threaded hole 130b. The upper surface of section 120 also has two upstanding U-shaped channels 132, 134 for receiving two of the three support spokes 106, 108, 1 10 as more fully explained below. Each free end of collar section 122 has a pair of securing channels 136, 138, confronting protrusions 126, 128, respectively, each channel having a threaded hole 130a for alignment with threaded holes 130b when collar 90 is assembled. Section 122 also includes an upstanding U-shaped channel 140 on the upper surface of lip 124 for receiving the remaining support spoke, and a support beam coupling 142 for accommodating attachment of support beam 112, all as more fully explained below.
Collar sections 120, 122 are assembled by first fitting the collar sections about the trunk 94 at a desired elevation and then pushing the two sections together until alignment protrusions 126, 128 seat in channels 136, 138 so that threaded holes 130a, 130b are aligned. Thereafter, collar 90 is secured to the trunk 94 by thumbscrews 150 which pass through aligned threaded holes 130a and 130b and seat against trunk 94, and by two additional pairs of thumbscrews 154, 155 which pass through screw holes (not shown) in collar sections 120, 122, respectively, these latter thumbscrews also seating against trunk 94. As shown, each thumbscrew has a grip 152 at its free end for firmly engaging the trunk, thereby firmly securing collar 90 in place.
Referring now to FIGS. 7, 9, 10A and 10B, support spokes 106, 108, 110 extend radially outward from collar 90, each spoke having a coupling end 156 and a support end 158. Each coupling end 156 has a hooked portion 160 configured to hook onto lip 124 of collar 90. Each support end 158 has a flat protrusion 159 integrally formed therewith and configured for insertion into axial bores 86 located on the underside of track sections 64 for supporting the track 12 about the Christmas tree 92. To fine adjust the height of track sections 64, and as shown in FIGS. 10A and 10B, the coupling end 156 of each support spoke 106, 108, 110 is fitted with a thumbscrew 164 passing through a post 165 and seating against collar 90. As shown, each post 165 has a slot 167 supporting a threaded nut 169 for fixing the position of the respective thumbscrew 164. As the method of adjusting the portion of spokes 106, 108, 110 with thumbscrews 164 is the same, only adjustment of spoke 106 will be described.
Still referring to FIGS. 10A and 10B, when thumbscrew 164a in spoke 106 is turned clockwise, thereby screwing it further into post 165a, the distal end of the thumbscrew pushes against collar 90 whereupon the spoke 106 is urged upwardly as shown by the dotted lines and by arrow 190 in FIG. 10B. This, of course, serves to raise the track section 64 supported on spoke 106 relative to collar 90. As will now be understood, the track section supported on spoke 106 may be lowered by turning thumbscrew 164 in a counterclockwise direction.
As lift 18 is substantially heavier than track 12, support beam 112 which secures lift 18 to collar 90 is sturdier than support spokes 106, 108, 110. As best shown in FIGS. 9 and 11 the support beam 1 12 has a first end 166 and a second end 168. The first end 166 has a "T"-shaped protrusion 170 configured for seating in the support beam coupling 142 on collar 90 and the second end 168 has a flange 169 configured for seating in a receiving slot 119 provided for the purpose on the inward facing surface of lift 18, thereby securing lift 18 to collar 90 in spaced relation from Christmas tree trunk 94. See FIG. 1.
Referring now to FIGS. 1-4, the operation of the display 10 will now be described. As shown, when figurine 30 is at the lower end 16 of the track 12 at the bottom of the lift 18, the cross-member 36 is positioned over the slot 62 in the bifurcated ramp 60. The figurine 30 remains stationary until the hooked end 58 of the next available pin 56 on endless belt 50 latches on to cross-member 36. As endless belt 50 rotates, it lifts figurine 30 to the top 20 of lift 18 which is at the upper end of track 12. When figurine 30 reaches the top of the lift, the momentum imparted by endless belt 50 causes figurine 30 to move forward thereby unseating cross-member 36 from pin 56 as the pin rounds the pulley 48, thereby disengaging figurine 30 from belt 50. Once disengaged, the continuous downgrade of track 12 causes the figurine 30 to traverse track 12 under the influence of gravity from the first end 14 to the second end 16 whereupon the cycle is repeated, such traversal being aided by the low friction of rollers 36. The result is a pleasing visual effect as figurine 30 repeatedly circles tree 92. In the preferred embodiment a plurality of figurines are included, thereby enhancing the visual effect.
In the preferred embodiment, track 12, lift housing 18, collar 90, support spokes 106, 108, 110 and support beam 112 are manufactured by injection molding utilizing any one of a variety of available thermoplastic resins, such as polystyrene.
Referring now to FIG. 12, the branches of some Christmas trees, such as artificial Christmas trees, are substantially sturdier than natural trees. Accordingly, when the display 10 is used in conjunction with an artificial tree, it may be possible to support the track 12 and lift 18 directly on the tree's branches, i.e. without the use of collar 90, support spokes 106, 108, 110 and support beam 112.
In the preferred embodiment of the invention, and as shown in FIG. 13, the display 10 includes three detachable legs 180 of varying lengths, each having a first end 182 and a second end 184. The first end 182 of each leg 180 is configured for insertion into axial bores 86 on the underside of selected track sections 64 and the second end 184 is configured as a foot for seating on a ground surface for supporting track 12 at an appropriate elevation. As shown in FIG. 13, in this embodiment the bottom of lift 18 also seats on the ground surface. As is now apparent, this feature provides the option of supporting display 10 on the ground, for example, about the base of Christmas tree 92.
Although I have herein shown and described the preferred embodiment of the invention, various changes and modifications will be readily apparent to those of ordinary skill in the art who have read the foregoing description. For example, substitute lifting means 18 may be utilized to transport the figurine from the second end of the track to the first end thereof. Rollers 36 may also be replaced with a low friction surface for easy translation of the track by figurines 30. Also, the device may be combined with a sound generating circuit for playing traditional Christmas melodies. As these as well as further changes and modifications are intended to be within the scope of the present invention, the foregoing description should be construed as illustrative and not in a limiting sense, the scope of the invention being defined by the following claims.
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The present invention is a Christmas display (10) resembling a ski-lift and ski-slope, for use in conjunction with a Christmas tree (92). The display (10) comprises a track (12) having a first end (14) and a second end (16), wherein the first end is at a higher elevation than the second end, and a lift (18) disposed between the first end (14) and the second end (16). The device also comprises a plurality of figurines (30) having a base configured for slidable movement along track (12) from the first end of track (12) to the second end of track (12) whereby the lift (18) transports the figurine (30) back to the first end (14) of the track (12) in a continuous manner. In the preferred embodiment, the display also comprises a support mechanism (90) for supporting the display on a Christmas tree.
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This is a continuation-in-part of application Ser. No. 08/388,248, filed Feb. 14, 1995, now abandoned.
BACKGROUND
The invention concerns an improvement in push rods used in valve actuators for internal combustion engines.
The conventional push rod is a rigid member acting in compression between a tappet reciprocated by a rotating cam and one end of a rocker arm that forces a valve open against a valve spring. In the assemblage of these components, a closed valve clearance or play, called lash, is initially set by a gap gauge or the like to ensure complete valve closure at the proper cycle of the engine piston usually corresponding to an off lobe cam position at the tappet. As the cam lobe rotates to drive the tappet, the push rod is forced along its axis, in compression driving one end of the rocker arm which in turn opens the valve against the valve spring at the opposite end of the rocker arm.
As the engine rpm is increased, the reciprocation and acceleration and deceleration forces on the valve actuator parts and specifically on the push rod attain high force levels. The lash that exists in the valve closed condition causes cycling metal to metal contact which is associated with valve actuator noise such as clatter, increased wear due to friction, metal to metal wear and diminished engine efficiency. The amount of lash initially set for the valve actuator will typically vary with wear, often increasing so that the problems of noise, increased friction and wear and still further lowering of actuator efficiency results.
SUMMARY OF THE INVENTION
A push rod is constructed with a lash take-up spring and oil pump assembly, mounted so as to be contained within at least one end of the rod body. This assembly includes an end part slidably inserted into a coaxial bore of the rod body and a biasing spring that urges the end part axially away from the mounting end of the rod body so as to create a spring biased slight axial extension of the overall rod length. In the preferred embodiment, the end assembly includes an oil pumping chamber accommodating the lash take-up spring and forming a cylinder-piston pump in communication with a coaxial oil duct in the rod that delivers oil to engine parts at the opposite end of the rod, such as to the rocker arm assembly. Means such as an internal clip mounted on a shank of the end part limit the axial movement of the part between a spring biased extension of the push rod length and a non-yielding minimal working rod length in which the end part movement is stopped against the mounting end of the rod body allowing the rod to act in full force compression to drive the rocker arm against the valve spring assembly to open the valve in reaction to the cam and tappet or lifter movements.
Further in another embodiment, the end assembly has a retainer insert fixed to one end of a hollow or tubular rod body. The insert, which may be generally cup-shaped, has an open-flanged end that seats against an axial end of the tubular rod body and has a closed recessed end. The movable end piece has a rounded head that fits against a pocket in the rocker arm or tappet lifter and a shank that slidably fits in a shank opening formed in the closed end of the cup-shaped insert. A lash take-up compression spring fits coaxially about the end piece shank and acts in compression between the recessed closed end of the insert and the underside of the head of the end part. Spring clip means is preferably used to retain the shank of the end part in the insert opening and limit the amount of axial extension or travel of the end part under the spring bias. The underside of the head forms a structure that moves down against a stop at the flange of the retainer insert and thus in effect against the axial end of the tubular rod body to transmit the compression force from the rounded head end to the rod body to accommodate the high compression force needed to operate the valve spring under the variable revolutions per minute required.
Further in the preferred embodiment, the end part has an oil bore provided along the end part axis through its shank and opening at the rounded head which communicates with the internal pump chamber and an inner axial duct in the tubular rod body for ducting oil to lubricate the corresponding end of the push rod where it engages the rocker arm or tappet. The spring biased axial movement of the end part is at least sufficient to take up the initial specified clearance or lash in the valve actuator assemblage and is preferably about 200% of the specified lash in order to continue to take up play as the parts wear between service adjustments in the valve actuator. Thus when properly and initially adjusted, the push rod has its end part slightly depressed against the lash take-up spring to approximately one half of the maximum extension. The lash take-up spring force is selected to be substantially less than the predetermined valve spring force to ensure that the rod end assembly does not deflect and thus does not partially open the valve during the valve closed portion of the camming cycle.
These and other features, advantages and aspects of the invention will become better understood by reference to the following detailed description and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an enlarged axial section view of the push rod shown shortened from its true length by broken lines mid-body of the push rod.
FIG. 2 is a further enlarged vertical cross sectional view of an end of the push rod of FIG. 1, showing in better detail the end assembly.
FIG. 3 is a diagrammatic view, partly in section with areas broken away, to illustrate the positioning and operation of the push rod in a valve actuator of an internal combustion engine.
FIGS. 4a and 4b are a diagrammatic view and an enlarged fragmentary, cross-section view of the currently preferred push rod assembly shown in a valve closed phase of the engine cycle.
FIGS. 5a and 5b are views corresponding to FIGS. 4a and 4b showing the push rod assembly in a valve opened phase.
DETAILED DESCRIPTION
With reference to FIGS. 1 and 2, the push rod 10 in accordance with one embodiment, is constructed of a substantially rigid metal tubular rod body 12. To one end of the rod body 12, an end assembly 14 is mounted and is shown to include an end piece 16, a cup-shaped retainer 18, a lash take-up spring 20, and a retainer clip 22. End piece 16 is generally elongated axially with an enlarged rounded head portion 16a, a smaller diameter shank portion 16b, a mid-body portion 16c of intermediate diameter, and a central axially extending oil duct 16d appearing in dotted lines in the drawings. Retainer insert 18 is of generally hat or cup shape, with a cylindrical main body portion 18a, an end 18b that has a radial flange, and a closed end 18c. Retainer insert 18 is press-fitted into a counter bore 12a of tubular rod body 12 and forced inwardly into the open tubular end of the counter bore until a lip of flange 18b rests against the rim or axial end of rod body 12 as shown in FIGS. 1 and 2. Counter bore 12a forms a slight shoulder or lip 13 against which the closed axial end of insert 18 seats when press fitted into tubular rod body 12 to further ensure transmission of adequate push rod force between head portion 16a of the movable end part 16 and the rod body through insert 18. Alternatively, a different insert configuration or elimination of insert 18 would provide an alternative embodiment in which end piece 16 is forced directly against the end of rod body 12 to provide the full valve opening force required.
The intermediate diameter mid-body portion 16c of end part 16 is of generally cylindrical shape and has a sliding clearance fit into the inner diameter 18d as best illustrated in FIG. 2. The free end of shank 16b slides axially freely in an opening 18e (see FIG. 2) and clip 22 held in a circumferential recess of shank portion 16b retains it and end piece 16 in retainer insert 18, yet allows axial movement of the end piece.
An opposite end of rod body 12 may also be fitted with a like or similar end assembly so that both ends have anti-lash extensions, but usually one end piece is sufficient. Here the opposite end of the push rod is provided with a fixed end piece 15 press fitted into that end of the rod body 12. An oil duct 15a is formed in the axial center of fixed end part 15.
With reference to FIGS. 2 and 3, during operation, the push rod 10 is installed in the valve actuator assemblage such as illustrated in FIG. 3 and the amount of lash specified for a closed valve condition is set by depressing rocker arm 30 against anti-lash push rod 10 to depress the head 16a of end piece 16 down into insert 18 against lash take-up spring 20. Although not shown in FIG. 2, this setup procedure causes a lower face 17 underlying head portion 16a of the end piece 16 to stop against the upwardly confronting shoulder surface 19 of insert flange 18b. By limiting the travel of end piece 16 in this manner, the amount of nominal lash in the valve actuator assemblage is set such as with a feeler gauge between rocker arm 30, shown in FIG. 3, and end 32 of the valve spring and adjacent valve stem 34 and 36, respectively. Then the rocker arm 30 is released, allowing lash take-up spring 20 to urge end piece 16 of the push rod to extend, taking up the preset lash in the valve actuator assembly. The amount of yielding extension provided by lash take-up spring 20 is pre-selected to be a fraction of the spring rate force of valve spring 34 to ensure that the valve head 38 remains closed during the off lobe position of the valve actuator. In other words, the anti-lash spring and anti-lash head assembly take up lash but do not override or force open the intended closed valve condition.
When the valve actuator cam 40 rotates or otherwise moves to cause the cam lobe to drive lifter or tappet 42 toward a valve opening position, the push rod end part is fully depressed, closing the lash gap as shown in FIG. 2 between head 16a and insert shoulder 19. The lash take-up spring 20 is now effectively removed from the actuator system and end part 16 acts as a non-yielding stiff unit with insert 18 and rigid rod body 12 transmitting the full cam actuating force against the spring valve and valve components 34 and 36 to force open valve head 38. The cycle continues until the valve head 38 closes and the compression force on the push rod 14 is relieved, allowing lash take-up spring 20 to take up the play by forcing head portion 16a of the end part axially outwardly of rod body 12.
By way of example, one embodiment of push rod 14 used an end part 16 of hardened 41-40 or 30 heat treated steel. A 50 thousands maximum gap is provided between face 17 of head portion 16a and shoulder 19 of insert 18, however this dimension can vary with engine design and required performance. Lash take-up spring 20 is a standard heat treated spring steel and is selected in this example to have a force of about 25 pounds over the operating deflection. Tubular rod body 12 is titanium to reduce the amount of inertia, and hence energy cost and drag, especially during high rpms.
With reference to FIGS. 4a and 4b and 5a and 5b, another and now preferred embodiment of the push rod assembly is illustrated in which lash take-up end assembly 14' is shaped and mounted at one end of rod body 12' and has an internal localized oil pumping cylinder and spring retaining chamber 50 behind the reciprocating shank of end piece 16'.
More particularly, the end piece 16' has a shank 16c' that is sized to slidably fit into a coaxial counterbore 12a' of the rod body 12'. An internal coaxial oil duct 12b' of diameter less than counterbore 12a' in rod body 12' communicates with spring and pumping chamber 50 and continues henceforth upwardly away from the pumping chamber along the length of the rod body opening at the opposite end of the push rod where it seats into rocker arm 30' as illustrated in FIG. 4a. A lash take-up compression spring 20' is mounted between the end face 16e' of shank 16b' and the opposed bottom wall 20' of the pumping cylinder chamber 50 to bias end piece 16 away from seating against rod body 12. Thus the underside of head 16a' of end piece 16' is pushed off seated contact with the rim 13' of push rod body 12' as illustrated in FIG. 4b.
A retainer clip 22' of the spring C-type is mounted in a circumferential recess on the shank 16c' of end piece 16' about mid-position of its length with a protruding edge portion of the clip 22' projecting outwardly to be retained in a recess 52 formed circumferentially in the interior wall of the counterbore 12a'. The axial extent of recess 52 limits reciprocation of end piece 16' but is sufficient to accommodate the intended movement, such as 50 thousandths, between its extended spring-biased lash take-up position as shown in FIG. 4b, and its valve opening retracted condition. The latter condition is shown in FIG. 5b when the underside 17' of the head 16a' is shouldered against the end 13' of the push rod body for forced opening of the valve against the heavier valve spring as illustrated in the companion FIG. 5a.
As the engine operates, rapid reciprocation of the push rod including the back and forth movement of the end piece 16 between its spring-biased lash take-up position as shown in FIG. 4b, and its closed retracted position shown in FIG. 5b causes a localized oil pumping action in chamber 50 of push rod 12'. Flow of oil that normally would occur under the nominal oil pressure of the engine through a lifter 56, conventional or hydraulic, into the coaxial oiler duct 12b' of the push rod is augmented by this localized pumping action.
The pumping action is due to the reciprocation of shank 16b' in chamber 50. Oil from lifter 56 passes up from the lifter seat, into duct 16d' of end piece 16' filling the pumping chamber 50 when head 16a' is extended. As the chamber constricts in volume due to the inward movement of the end piece shank 16b', oil is forced and hence pumped, as in a piston cylinder hydraulic pump, upwardly into the relatively smaller diameter rod body duct 12b' where it is then discharged either at the contact seat with the rocker arm 30' or preferably through an arm dispersal port 58 provided for that purpose in the rocker arm extremity in line with or in communication with the opening of the oil duct 12b' at the upper end of the push rod body 12'.
The amount of pumping action and its effectiveness increases along with the increase in the reciprocation rate of the end piece 16' in rod body 12' such that at higher engine RPM with more rapid reciprocation of the push rod and end piece 16, greater local pumping action and thus increased lubrication results. Furthermore, the lash take-up spring 20' holds head 16a' in seated contact with lifter seat 56a, minimizing the amount of oil bleed at this coupling point and hence enhancing the delivery of oil to the push rod upper end at the rocker arm.
Preferably the size and hence volume of the pumping chamber 50 and the shank of the end piece 16' is selected so that a 50 to 100 thousandths axial movement of end piece 16' causes a volume displacement sufficient for the engine size and lubrication requirements. In relation, the size of the internal coaxial oiling duct 12b' in the main body of the push rod is preferably 1/2 or less than the diameter of the chamber 50.
With these considerations, this now preferred embodiment of the push rod lash take-up spring and oil pump assembly produces a highly effective mechanism for oiling the contact points at the ends of the push rod, the rocker arm and the various parts adjacent to the rocker arm as a result of oil being forced through duct 12b' under this augmented, localized pumping action. The invention not only minimizes the amount of free play noise and vibration that exists in the conventional push rod without the lash take-up spring-biased end piece, but also enhances the oiling of the associated parts of the engine by directing the oil to the most critical wear components and at a flow rate that increases with engine speed. Furthermore, the disclosed construction of the push rod 10' with its self-contained lash take-up end piece and auxiliary oil pump assembly being fully contained in the geometry of a typical conventional push rod allows the push rod 10' to be used as a replacement part to quiet an engine, reduce its valve actuator wear and enhance oil delivery to the related parts.
While only particular embodiments have been disclosed herein, it will be readily apparent to persons skilled in the art that numerous changes and modifications can be made thereto, including the use of equivalent means, devices, and method steps without departing from the spirit of the invention.
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A push rod is constructed with a self-contained lash take-up spring and auxiliary oil pumping assembly inserted at an end of the rod body and includes an end part slidably mounted relative to the rod body and a biasing spring that urges the end part axially to extend the push rod length to take up the play of normal lash in a valve actuator of an internal combustion engine. Axial movement of the end part is constrained between a yielding maximum extension of the push rod under spring bias and a non-yielding minimal working rod length in which the end part movement is stopped against an end of the rod body for pushing open the engine valve in reaction to cam and tappet movements. Reciprocation of the end piece relative to the rod body causes localized oil pumping action that delivers enhanced oiling through the rod body to the valve actuator parts.
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CLAIM TO PRIORITY
[0001] This patent application claims the benefit of, and priority to, U.S. Provisional Application No. 61/438,384, which was filed on Feb. 1, 2011, the contents of which are hereby incorporated by reference into this patent application.
TECHNICAL FIELD
[0002] The present disclosure relates generally to the field of communications, and more particularly to the selective communication of advertisements.
BACKGROUND
[0003] Computer based selective advertising is well known. For example U.S. Pat. No. 7,496,943 to Goldberg et al. entitled Network System for Advertising describes selective advertising based on user profiles or behaviors, and U.S. Pat. No. 7,930,207 to Merriman et al. entitled Method of Delivery, Targeting and Measuring Advertising Over Networks describes advertising based upon behavior or profile statistics compiled on individual users. Said patents are hereby incorporated by reference. Selective advertising using a computer or mobile cell phone is an effective way to target advertisements that are meaningful to the user of the computer. Such advertisements often help a consumer make a more informed decision when purchasing a desired product or service.
[0004] Selective based advertising is also an effective way to communicate to potential customers by product or service providers. More traditional print media forms of advertising are often mass distributed to large groups of individuals, wherein many individuals have no particular interest in most of the advertisements presented in the print media. While distributions based on user demographics may help improve the effectiveness of advertisement in the print media, it cannot be as effective as statistically analyzing a database of individual user profiles or behaviors and selectively communicating advertisements in response thereto. Since advertisement adds cost to the product or service delivered by the provider, computer based selective advertisement is a more cost effective method of communicating with potential customers.
[0005] Even though computer based selective advertising is beneficial to both the consumer and the provider of products or services in the initial purchase of the product or service, after the purchase of the product or service, there is an arising issue. The user may continue to receive advertisements of the product or service after the purchase even though the user is no longer receptive to the ad because the product or service has been purchased. This results in the delivery of annoying advertisements to users and may alienate the user, thereby reducing any customer loyalty or good will that may have resulted from the transaction. Furthermore, the product or service provider pays for the selective delivery of advertisements that are no longer of interest to the user. This not only adds unnecessary costs, but may even be detrimental to the relationship with the consumer, even though statistical analysis of the user's behavior or profile indicates that the user should be interested.
[0006] Nevertheless, as the purchased product or service nears the end of its useful life, the user may again be interested in a subsequent purchase. Advertisements at this time may be meaningful to the user, while advertisements sent during the major portion of the life of the purchase are undesirable to both the consumer and the product or service provider. For example, a fourteen year old girl, such as the inventor, may be a beauty parlor customer every three or four months. Thus the problem arises when beauty parlor advertisements are sent after a visit by the user because the ads are substantially useless to both the user and the beauty parlor service providers. The user does not need the services of a beauty parlor at that time and beauty parlors expense for advertisements sent to the user during that time are a waste of investment. However, advertisements from competing beauty parlors sent to the user at a later time may be more effective. Thus, what are needed are solutions to the aforementioned problems.
SUMMARY OF THE INVENTION
[0007] The following summary is exemplary and not intended to limit the scope of the claimed invention.
[0008] My invention is called the Product Based Advertisement Selection. The technology used may include a product scanning application and an application for advertisement selection. This invention solves the problem of unnecessary advertisements presented to a person that already owns the product being advertised. Advertisements cost companies millions of dollars annually. Advertisements are presented to users of internet social sites, internet media sites and web portals. An advertiser is charged for each presentation of their ad on the internet. An advertiser would not want an unnecessary ad to someone who already owns their product. This invention allows the advertiser to have targeted advertisements to perspective new customer while saving enormous amounts of money on unnecessary ads to existing customers.
[0009] The merger of the internet and television is currently occurring the many televisions utilize DVR (digital video recorder) which have internet connectivity. There is on demand programming; again, done through the internet and many episodes of TV shows are watched via the internet through network websites. Today, in fact, before you watch a television show on the internet you are asked which advertisement you would like to see. This invention utilizes your past purchases to make a more intelligent choice of advertisements to be targeted to you.
[0010] One example of how it works for the user would be utilizing a visual based barcode reader application either on a cell phone, webcam, or scanner. The product barcode information would be stored either on the user's computer, cell phone, or central database. When the user accesses the internet their product ownership information is transferred to the advertisement database. Advertisement selection profiles would be done and the appropriate ads selected for each user not unlike the way cookies give information about a particular user on a computer to a particular website. For example advertisements for a product the consumer already owns would not be sent to them. Thereby saving the advertiser money and saving the user from the frustration of experiencing ads they don't need to experience.
[0011] How to make money with this invention: the advertiser has the potential to save for unnecessary presentation of ads. To entice the user to utilize this application a rebate could be offered at the time the product is purchased.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] Example embodiments of the present disclosure will be described below with reference to the included drawings such that like reference numerals refer to like elements and in which:
[0013] FIG. 1 is an illustration of the system.
[0014] FIG. 2 is an illustration a process flow of the system.
DETAILED DESCRIPTION
[0015] For simplicity and clarity of illustration, reference numerals may be repeated among the figures to indicate corresponding or analogous elements. Numerous details are set forth to provide an understanding of the embodiments described herein. The embodiments may be practiced without these details. In other instances, well-known methods, procedures, and components have not been described in detail to avoid obscuring the embodiments described. The description is not to be considered as limited to the scope of the embodiments described herein.
[0016] FIG. 1 shows an illustration of the system. A user 100 sits at a desktop computer terminal 102 consisting of a keyboard, display, mouse, processing unit and computer readable storage media (not shown). Although a classical desktop computer is shown, other computer systems are anticipated including a laptop, cell phone, smart phone, super phone, PDA, tablet or computer based signage. The display includes a portion 104 for internet surfing or operating applications of the computer, and an advertising portion 106 where ads are selectively presented to the user based upon monitored behavior of the user in a manner known to those familiar with the art.
[0017] The computer is coupled to a cloud of 110 of process that operate external to the computer. Behavior monitor 112 includes an internet interactions monitor 114 that monitors various behaviors of the user. This may include monitoring internet sites visited, products purchased on the internet, emails, voice messages, texts messages, instant messages, social media messages or other information exchanged by the user. The behavior monitor communicates with a selective advertiser process 120 which has a database 122 of advertisements from product or service providers subscribing to the advertising service. Each user behavior profile 124 is accumulated and used to select specific advertisements from the advertisements database that are most relevant to the user based upon behavior.
[0018] When a user identifies a product or service 130 , for example by scanning a barcode 132 associated with it using a barcode reader 134 , the identification is also made available to the selective advertiser process 120 and stored in the user identified product or service database 140 . If the product or service has a life expectancy that the life data 142 is also stored in database 140 .
[0019] Alternate or modified approaches to the user identification of product or services are anticipated. For example, if terminal 102 was a smartphone, then barcode reader 134 could be incorporated as part of the smartphone. Alternately, a RFID or NFC reader could be used in place of a barcode reader. User identified products or services can also be determined my monitoring purchases of the user. In another example, credit card purchase information of the user can be mined for such identification, or internet purchase made with the terminal can be monitored in order to determine a signal indicate of the purchase of the product or service. Alternately, if the terminal 102 is an electronic wallet capable of facilitating purchase transactions, the user identified products or services can be minded by the electronic wallet at the time of a transaction. The aforesaid examples show processing a signal indicative of a selection of a product or service by the user. It is not necessary that the product or service actually be purchased by the user in order for it to be a selection by the user, thus the user could block ads for products simply by scanning a barcode of the product without purchasing it.
[0020] Advertisements are then selected by the selective advertiser based on user behaviors and user identified products or services and communicated to the user through and ad communicator 150 which causes the ads to be displayed to the user on the advertising portion 106 of terminal 102 .
[0021] While terminal 102 is shown to have a slit screen layout where a portion of the screen is designated for advertisements 106 and another portion 104 is designated for other processes, other layouts and configurations are also contemplated. For example the advertisements portion 106 may occupy the entire screen for a period of time, or may occupy a portion of the screen for a period of time. Advertisements may be video only using a display, audio only using a speaker or a combination of video and audio content using both display and speaker.
[0022] FIG. 2 illustrates a process flow of the system operating within a computing system having non-transitory computer readable storage media (not shown), the computing system may be highly distributed. Step 200 monitors the user behavior in manners know to those familiar with the art. Step 202 then determines the user identified product or service and corresponding life. In step 204 a plurality of advertisements for product or services providers are accumulated.
[0023] Step 206 determines if a user is ready to receive an advertisement. If the user is browsing the internet, and the browser window facilitates advertising, then the user is ready to receive an advertisement. Alternately, social media and other content delivery processes may be able to facilitate delivery of advertisements.
[0024] Step 208 selects an advertisement from database 122 . At step 210 , a check is run to determine if the advertisement is related to a user behavior. Numerous methods for implementing process are known to those familiar with the art. For example, if the user often views popular culture web sites targeting teenage girls, then advertisements for trendy local beauty parlors would likely found to be related to the user behavior. If the ad is not related then another ad is selected at steps 208 .
[0025] Step 212 checks if the ad is related to an identified product or service. If not, then the ad is communicated to the user at step 218 and the advertiser is invoiced for delivery of the ad at step 220 . However, if the user has identified the product or service at step 214 , then the ad will not be delivered and another ad selected at step 208 . The non-selected ad may be optionally related to the product or service. Optional step 216 may nevertheless allow for delivery of the ad if there is an associated life and the life is approaching or exceeding expiration.
[0026] For example, the beauty parlor advertisement may be selected based on user behavior at step 210 . However, if the user recently visited a beauty parlor then any beauty parlor ad would be blocked at step 214 . In one embodiment, only an ad for the visited beauty parlor would be blocked, but in another embodiment, ads for any beauty parlor service or complementary product would be blocked. The beauty parlor visit would be identified by either the mining data indicating that the user paid for products or services with a credit card or an electronic wallet, or scanning a barcode related to a beauty parlor product or service. Optionally, the beauty parlor product or service may have an associated life. The life may be predetermined, statistically ascertained, set by the user or set by the product or service provider. If the life of a beauty parlor visit is 4 months, then beauty parlor ads would be blocked for a substantial portion of the life, until the life was approaching or exceeding expiration. For example, beauty parlor ads would be blocked for the first month after a beauty parlor visit was identified, but would be communicated to the user around or after the fourth month after the visit.
[0027] In another example, if the user behavior indicated that Wii gaming applications were related to their behavior, then an ad for a popular game such as SIMs for the Wii could be selected. If the user purchased the game, then future ads for the purchased version of the game would be blocked because the user would no longer be in the market for the game, and would likely find such ad annoying. Also, the provider of the game would not be invoiced for delivery of the ad. Thus the user is less annoyed and the provider costs are reduced. Since in this example, the Wii SIMs game has no effective life, then the optional step 216 of allowing the ad as the expiration of life is approached or exceeded is not required.
[0028] In another example, if the user behavior indicated that figure skating were related to their behavior, then an ad for figure skates could be selected. If the user purchased figure skates, then future ads for the figure skates would be blocked because the user would no longer be in the market for figure skates, and would likely find such ad annoying. Also, the provider of the skates would not be invoiced for delivery of the ad. Thus the user is less annoyed and the provider costs are reduced. Since in this example, figure skates have a very long effective life, five years for example, then the optional step 216 of allowing the ad as the expiration of life is approached or exceeded would execute substantially five years thereafter. However if the user was known to be a twelve year old girl and demographics showed that twelve year old girls require new skates substantially twenty four months after purchase because of their growth patterns, then optional step 216 would block ads for a time less than or equal to the twenty four months, and then permit ads for figure skates thereafter.
[0029] While steps 202 , 212 and 214 are shown as occurring in cloud 110 , in an alternate embodiment, the ads can be blocked by terminal 102 by implementing these steps in the terminal and maintaining databases 140 and optional 142 in the terminal. This would be particularly applicable to a smartphone or super phone with electronic wallet capabilities. Here the electronic wallet would monitor purchase by the user and then selectively block ads selected by conventional targeted advertisement processes occurring in the cloud from being presented to the user on the smartphone. This embodiment also applies to other terminals, such as personal computers, laptops or tablets, able to both present advertisements selected based upon user behavior and facilitate product identification or purchases by the user.
[0030] Thus, what has been shown is the selection from a plurality of advertisements an advertisement that is related to the behavior of the user but not related to a product or service identified by the user.
[0031] The present disclosure may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the disclosure is, therefore, indicated by the appended claims rather than by the foregoing description. All changes that come within the meaning and range of equivalency of the claims are to be embraced within their scope.
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The present disclosure selectively blocks advertisements to a user based upon recent purchases of the user. The selectively blocked advertisements may be chosen from a group of advertisements chosen for the user based upon monitored behaviour of the user.
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BACKGROUND OF THE INVENTION
This invention relates generally to engine starting systems and more particularly to starting systems for air starters for use on vehicles and the like. In prior art air starting systems, the pressure fluid is applied to the starter and the starter operated at self governed speeds, limited by the available air pressure and starter mechanical design. In many cases, this resulted in inefficient utilization of the available air pressure and occasionally cranking speeds in excess of manufacturer's recommendations.
The foregoing illustrates limitations known to exist in present devices and methods. Thus, it is apparent that it would be advantageous to provide an alternative directed to overcoming one or more of the limitations set forth above. Accordingly, a suitable alternative is provided including features more fully disclosed hereinafter.
SUMMARY OF THE INVENTION
In one aspect of the present invention this is accomplished by providing a starter control system for an engine starter comprising means for sensing engine RPM; means for determining engine off condition RPM; means for determining a minimum cranking RPM; means for determining a maximum cranking RPM; means for determining an engine running RPM; and control means for establishing a desired engine cranking and starting sequence in response to the condition sensed sequenced response of the above listed means.
The foregoing and other aspects will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawing figures.
BRIEF DESCRIPTION OF THE DRAWING FIGURES
FIG. 1 is a schematic view illustrating an embodiment of the present invention as applied to a vehicle starter;
FIG. 2 is a partial schematic showing the control circuit for the engine starter according to the present invention;
FIG. 3 is a cross sectional view of a starter control valve according to the present invention;
FIG. 4 is a graph representing starter operation with and without the control circuit of the present invention in terms of operating RPM and tank pressure vs. time; and
FIG. 5 is a schematic control diagram for the engine starting system.
DETAILED DESCRIPTION
Referring to FIG. 1, a pneumatic pressure fluid or air starting system for a vehicle is shown comprising a starter driven by the pneumatic pressure fluid having its output on a pinion gear 7, is connected to a pressure fluid source or tank 2 by means of a hose or pipe 5 communicating through a valve assembly 3. Hose flange connections 4 and tank flange connection 6 are shown for convenience of assembly. It should be understood that other hose or pipe connections might be utilized.
In a typical starter system of the prior art, a pushbutton or the like would be utilized by the operator to activate the valve to permit pressure fluid to reach the starter 1. In a typical prior art system, therefore, the output of the starter was controlled by the operator directly and the operating speed of the starter was dependent in part by the operator's judgement and the available pressure of the pressure fluid in the tank. The system design permitted an unskilled operator to substantially waste available pressure fluid in inefficient starting attempts.
According to the present invention, the starting system permits selection of a start cycle which is substantially controlled within engine manufacturer's recommended specifications permitting far better utilization of the available pressure fluid and thereby substantially extending the number or duration of the start cycles.
According to the present invention, the major components of the present starting system are shown in FIG. 5 and includes a starter motor 1 having its output on a pinion 7 which in turn drives the engine flywheel 50. A proximity pickup sensor 15 detects the rotation of the engine flywheel and sends a frequency signal to a frequency voltage device contained within the central processing unit 20. The frequency signal representing engine RPM is sent to the central processing unit 20 and a control signal is developed, as will later be described, to be sent to a control valve 3, or in the case of an electric starter, a voltage regulator device. The control valve selectively transmits the motive power to the starter motor from the stored energy device (tank 2 or electric battery).
FIG. 2 shows the interconnected control signals. A 12 volt power source 12 is applied to the control unit 20 by means of a pushbutton 10. A ground 13 is provided also for this purpose. The proximitor sensor 15 sends a pulse signal to a frequency to voltage device 22 which converts the signal to an engine rotation signal (RPM) which in turn is sent to the control unit 20 in response to engine rotation. The control unit provides a pressure signal 14 and an exhaust signal 15 to the valve assembly 3 in accordance with the sequence which will later be described.
FIG. 3 shows a control valve 3 according to the present invention. The control valve includes an inlet 31 for receiving pressure fluid from the tank 2, and an outlet 32 for providing pressure fluid to the starter contained within the valve body 33. A valve element 35 is disposed between the pressure fluid inlet and outlet in an end cap 38 provided for the purpose of holding and guiding the valve element. A valve spring 39 is provided to bias the valve element 35 to a closed position. A valve stem 40 coacts with a control diaphragm 36 to position the valve element for pressure fluid flow control. The diaphragm 36 divides a chamber within the valve body 33 into an upper cavity 42 and a lower cavity 43.
The lower cavity communicates with the outlet fluid pressure. The upper cavity receives control pressure from the pressure fluid inlet via a control pressure conduit 37 and a solenoid operated valve comprising a solenoid 34 having a pilot plunger valve 41 communicating with the control pressure conduit 37. A corresponding solenoid operated control valve 34e (See FIG. 2) having a plunger valve 41e (not shown) selectively communicates an exhaust passage 47 (shown dotted in FIG. 3) from the upper cavity to atmosphere. The valve functions in accordance with commands issued by the control unit 20 to the solenoids 34 and 34e as follows.
In operation. Once the start pushbutton 10 is depressed, the electronic control unit compares the signals which it receives to several references. The references are (a) engine off, comprising an RPM signal of, for example, less than 25 RPM; (b) a minimum desired cranking RPM; (c) a maximum desired cranking RPM; and (d) an engine running RPM (for example, greater than 300 RPM).
The electronic control unit 20 acts on the RPM signal relative to each of the above four references. First, on depression of the pushbutton, which applies the 12 volt power source, the control unit compares the signal to engine off (a reference). If the engine is not turning, the box will activate the coils of the pressure 34 (normally closed) and the exhaust 34e (normally open) solenoid valves. This in turn pressurizes the upper cavity 42 of the regulator valve allowing air to flow to the starter.
Second, when the signal RPM exceed the minimum cranking speed, the control unit de-energizes the pressure solenoid 34, trapping the air pressure in the upper cavity 42 of the regulator. In this mode, the control is inactive as the regulator supplies a fixed pressure to the starter.
Third, when the signal RPM exceeds the maximum cranking RPM, the control unit de-energizes the exhaust solenoid 34e, allowing the upper cavity 42 of the regulator to vent and the regulator to move towards the closed position.
Fourth, when the engine starts, it accelerates to its governed idle speed (typically above 300 RPM), the signal initiates the engine running reference. At this point, the control unit locks out to prevent accidental start attempts while the engine is running. This system will only reset after the RPM signal returns to below the engine off reference.
Referring to FIG. 4, the typical start sequence RPM according to the prior art is indicated by the curve designated by the reference numeral 50. The governed engine RPM according to the present invention is shown by the curve designated by the reference numeral 51. The corresponding tank pressure for the prior art situation is shown by the curve designated by the reference numeral 52. The tank pressure according to the present invention is shown by the curve designated by the reference numeral 53.
As may now be appreciated by one skilled in the art, if the effective cranking speed of the engine is, for example, above 150 RPM, the effective time of start is increased from approximately 25 seconds to approximately 35 seconds representing a nearly 40 percent increase in the effective starting time.
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The engine starting system herein described controls an engine starting sequence which prevents start attempts when the engine is running and regulates the starting function within a control range of revolutions for efficient use of the available starting power either in the form of pressurized fluid from a tank or electrical discharge of a battery to effectively extend the efficient starting cycle of an engine.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a process for preparing acrylamide by bringing acrylonitrile into contact with water in the presence of a copper-based catalyst to hydrate acrylonitrile. More specifically, it relates to a process for preparing high-quality acrylamide which permits the manufacture of a polymer having a sufficiently high molecular weight and good water solubility.
2. Description of the Related Art
Acrylamide has been heretofore used in the form of an acrylamide polymer in papermaking chemicals, flocculants, oil recovery agents and the like, and in addition, it has many uses as a comonomer for various kinds of polymers. In the old days, acrylamide for these uses was manufactured by the so-called sulfuric acid method, but in recent years, a contact hydration method which comprises carrying out a reaction in the presence of a copper-based catalyst has been developed. Nowadays, this catalytic hydration method has been industrially practiced instead of the sulfuric acid method.
Among the above-mentioned uses of acrylamide, particularly the flocculants here also recently applied to the treatment of waste water, and in consequence, substantial efforts have been made to improve the quality and performance of acrylamide. Above all, with regard to the acrylamide polymer which can be used as the flocculants, there is a remarkable tendency that its molecular weight which is considered to have a direct influence on the performance is increased, and in recent years, an acrylamide polymer having a high molecular weight of about 10,000,000 or more, particularly about 15,000,000 is required. This molecular weight is much higher as compared with a molecular weight of usually 1,000,000 or less which is required for the acrylamide polymer for other uses or another polymer. In addition, since the obtained acrylamide polymer is usually dissolved in water when used as the flocculants, it is necessary that the acrylamide polymer is promptly dissolved without leaving insolubles. Furthermore, in view of an acrylamide monomer being poisonous, it is required that the unreacted monomer in the polymer be minute, for example, 0.2% by weight or less.
These requirements are incompatible with the increase of the molecular weight, and in order to meet both of them, substantial efforts have now been made. Although this high-molecular acrylamide polymer is only one use of acrylamide, if such acrylamide is not suitable for this use, it is not appplicable for general use. The present invention is concerned with a process for preparing acrylamide which is applicable to many uses inclusive of this use.
The molecular weight referred to in the present invention is a value measured by a test procedure shown in Example 1 which will be hereinafter described. In the case that the polymer obtained in an aqueous medium is dried to form a dry powder having a water content of 20% by weight or less, particularly 10% by weight or less and this dry powder is then used, much attention is paid to water solubility, and the water solubility referred to in the present invention is also mainly employed in this meaning.
The preparation of the acrylamide polymer having the high molecular weight and the sufficient water solubility depends largely upon not only the preparation process of the polymer, but also the quality of the acrylamide. Therefore, in preparing acrylamide from acrylonitrile by the catalytic hydration method, for the purpose of inhibiting the formation of by-products, various methods regarding the improvement of synthetic reaction systems have been reported. In the preparation of acrylamide, it is necessary to sufficiently purify acrylamide, and usually the purification of acrylamide is carried out through an ion exchange resin. However, some kinds of impurities cannot be removed by conventional ion exchange resin purification, and for the sake of the preparation of higher-quality acrylamide, some methods have been suggested.
For example, Japanese Patent Publication No. 12409/1975 (corresponding to U.S. Pat. Nos. 3,911,009 and 3,962,333) have suggested a method in which a copper salt such as copper nitrate or copper acetate is added to a synthetic reaction system to remarkably improve the activity of a copper catalyst, and instead of adding the copper salt, a part of the copper catalyst may be converted into a copper salt, and for this conversion, an inorganic acid or an organic acid is added. In this case, metallic copper is required to be partially oxidized prior to use or simultaneously. Moreover, on pages 23 to 24 of Khim. Technol., 1983 (3), it is described that sulfuric acid or acrylic acid is added to a system using a reduced copper catalyst, thereby improving the reaction rate and selectivity, and this is due to a salt formed by a reaction of the acid with oxides of copper.
Furthermore, according to Japanese Patent Laid-Open No. 57663/1992 corresponding to U.S. Pat. No. 4,820,872 (PCT WO 86/00614), there has been suggested a method in which an oxidizing agent and an oxidized catalyst are dissolved and removed or reducing agent is added, in the presence of a catalyst such as Raney copper; and concretely, a combination of copper nitrate and an organic acid such as acetic acid is described. In consequence, the formation of by-products can be inhibited.
Japanese Patent Laid-open No. 203654/1988 has described that nitric acid or a nitrate and (meth)acrylic acid and/or its salt are added to a synthetic reaction system to prevent the activity of a catalyst and the quality of a monomer from deteriorating. In addition, in preparing acrylamide, a stable operation is possible for a long period of time.
Japanese Patent Publication No. 21220/1986 has described that at least one material selected from the group consisting of ammonia, ureas, aromatic amines, primary and secondary lower alkylamines, and primary and secondary lower alkanolamines is added to a synthetic reaction system to particularly inhibit the secondary formation of impurities which cannot be removed by a conventional ion exchange resin treatment, and an acrylamide polymer which can be prepared from acrylamide obtained under such conditions has a high molecular weight and a sufficient water solubility. Moreover, a strongly acidic cation exchange resin is used in the purification step of acrylamide, whereby these additives can be easily removed.
According to Japanese Patent Laid-open No. 73727/1979, a phenol substituted at its meta-position is added to a synthetic reaction system, whereby the secondary formation of impurities which cannot be removed by a conventional ion exchange resin treatment can be inhibited. Furthermore, a strongly basic anion exchange resin is used in the purification step of acrylamide to easily remove the above-mentioned additive, and an acrylamide polymer which can be prepared from acrylamide obtained under such conditions has a high molecular weight and a sufficient water solubility.
However, Japanese Patent Publication No. 12409/1975 has described a method for preparing acrylamide which comprises bringing acrylonitrile into contact with water in the presence of a copper-based catalyst to hydrate acrylonitrile, and in this case, nitric acid or a nitrate is added. This method is excellent as a means for maintaining and improving a catalyst activity. However, probably due to the accumulation of copper oxidized in a reactor with the elapse of time, it has been admitted that the secondary formation of impurities such as ethylene cyanohydrin increases and the activity of the catalyst deteriorates. The quality of acrylamide can be evaluated on the basis of the water solubility and the molecular weight of the prepared acrylamide polymer, but the quality of acrylamide obtained by this method deteriorates with time.
A method for dissolving copper oxides accumulated in the reactor with an acid or the like disclosed in the above-mentioned Japanese Patent Publication No. 12409/1975, pages 23 to 24 of Khim. Tekhnol., 1983 (3), and Japanese Patent Publication No. 57663/1992 (PCT WO 86/00614) is effective to decrease ethylene cyanohydrin and the like which are impurities caused by the presence of copper oxides. However, the catalyst activity cannot be recovered only by dissolving the copper oxides of the catalyst with acid whose activity has once deteriorated due to the formation of the copper oxides, and in a certain case, the activity further deteriorates. The quality of acrylamide obtained by these methods, i.e., the water solubility and the molecular weight of a polymer obtained by its polymerization are not improved, and when a certain kind of acid is used, it has been admitted that the quality conversely deteriorates.
In the method disclosed in the above-mentioned Japanese Patent Publication No. 21220/1986, at least one material selected from the group consisting of ammonia, ureas, aromatic amines, primary and secondary lower alkylamines, and primary and secondary lower alkanolamines is added to a synthetic reaction system, the catalyst activity noticeably deteriorates and the quality of acrylamide is hardy improved, the reason is probably that the added compound has been absorbed by the catalyst.
In the method of Japanese Patent Application Laid-open No. 73727/1979, a phenol substituted at its meta-position is added to a synthetic reaction system, the deterioration of the catalyst activity does not take place, and when acrylamide prepared by this method is treated with a strongly basic anion exchange resin, the phenol substituted at the meta-position can be removed. The quality of the thus obtained acrylamide is admitted to be higher than that of acrylamide obtained by the method described in Japanese Patent Publication No. 21220/1986 which comprises adding an amine to a synthetic reaction system, but the quality is still insufficient. In addition, the phenol substituted at the meta-position can be removed with a strongly basic anion exchange resin only, and in a removal step, acrylamide itself hydrolyzes to form acrylic acid, so that the exchange capacity of the resin noticeably deteriorates. Moreover, the regeneration of the resin is difficult, and acrylamide is liable to polymerize in the resin layer during the feed of an aqueous acrylamide solution. In consequence, acrylamide obtained by this method is not practical.
SUMMARY OF THE INVENTION
The present inventors have intensively investigated an additive to be added to a synthetic reaction system in preparing acrylamide by bringing acrylonitrile into contact with water in the presence of a copper-based catalyst to hydrate acrylonitrile for the purpose of obtaining a sufficient water solubility and molecular weight characteristics of an acrylamide polymer which can be formed by polymerizing acrylamide. As a result, it has been found that the secondary formation of impurities which cannot be removed by a conventional ion exchange resin treatment can be inhibited by adding a compound having an active methylene group and an acidic group in one molecule or a salt of the compound to the reaction system; the added additive can be easily removed by the use of a weakly basic or a medially basic anion exchange resin; and an acrylamide polymer prepared from the thus obtained acrylamide has a high molecular weight and a sufficient water solubility. In consequence, the present invention has now been completed.
That is to say, the present invention is directed to a process for preparing acrylamide by subjecting acrylonitrile to a hydration reaction in the presence of a copper-based catalyst, said process comprising the step of allowing a compound having an active methylene group and an acidic group in one molecule or a salt of the compound to be present in a reaction system.
When the compound having the active methylene group and the acidic group or a salt of the compound is added in accordance with the above-mentioned process of the present invention, it is possible to inhibit the secondary formation of impurities which cannot be heretofore removed, without any deterioration of the catalyst activity, and high-quality acrylamide can be obtained which permits the formation of an excellent flocculant having a sufficiently large molecular weight and a good water solubility.
DETAILED DESCRIPTION OF THE INVENTION
Next, reference will be made to the gist of a process for preparing acrylamide of the present invention.
Examples of a copper-based catalyst for use in the present invention include
(A) a combination of copper in the form of copper wire or copper powder with copper ions;
(B) a copper-base of catalyst (reduced copper) by reducing a copper compound with a reducing agent;
(C) a copper-based catalyst (copper as a decomposed copper) obtained by decomposing a copper compound with heat or the like, and
(D) a copper-based catalyst (Raney copper) obtained by dissolving the aluminum out of a Raney alloy with an alkali or the like. It can be presumed that the main component of any one of these catalysts is an elemental copper.
The copper-based catalyst may be supported on a conventional carrier, and it may contain a metal other than copper, for example, chromium or molybdenum.
It is desirable to avoid the contact of the catalyst with oxygen or an gas containing oxygen before and after the use of the catalyst, because if the catalyst comes in contact with oxygen at a time of the use or reuse, the activity of the catalyst is lost and the formation of a by-product such as ethylene cyanohydrin is increased.
The hydration reaction of acrylonitrile in the present invention is carried out in the presence of the above-mentioned copper-based catalyst as follows. The reaction is carried out continuously or batchwise in a liquid phase while using the catalyst in the form of a suspended bed or fixed bed. The weight ratio of acrylonitrile to water, both to be used during hydration, can be determined practically as desired. The preferred weight ratio may be in a range of from 60:40 to 5:95, more preferably 50:50 to 10:90. The conversion of acrylonitrile is preferably in a range of from 10 to 98%, more preferably from 30 to 95%. The reaction temperature in the hydration reaction of acrylonitrile with water is preferably in a range of from 50° to 200° C., more preferably from 70° to 150° C.
In a reactor, there is maintained a pressure based on a vapor pressure due to the above-mentioned temperature and composition or based on this vapor pressure and the addition of an inert gas such as nitrogen. Thus, the pressure in the reactor is usually in the range of from atmospheric pressure to 10 atm.
Dissolved oxygen, contained in materials such as the catalyst, acrylonitrile and water which are fed to the reactor impairs the activity of the catalyst and increases the occurrence of by-product such as ethylene cyanohydrin, and therefore it is also desired to maintain the interior of the reactor under an oxygen-free atmosphere. After the hydration reaction, a liquid reaction mixture is taken out of the reactor, and this solution mainly contains unreacted acrylonitrile, unreacted water, acrylamide, a by-product such as ethylene cyanohydrin and copper.
The reaction solution obtained by the above-mentioned reaction, if necessary, is subjected to a usual vaporization or distillation operation to obtain a concentrated aqueous acrylamide solution, and unreacted acrylonitrile and water as distillates. These recovered material can be used again as fresh reaction materials.
Here, the reaction solution which has not undergone the concentration and the aqueous acrylamide solution which has undergone the concentration will be called the solution containing acrylamide.
The aqueous acrylamide solution obtained by concentrating the reaction solution (hereinafter referred to simply as "aqueous acrylamide solution") is then subjected to a suitable purification step such as a cation exchange treatment, a chelate resin treatment, an anion exchange treatment, an air or oxygen gas treatment or an active carbon treatment. In addition, there can also be employed the so-called synthetic adsorption resin (e.g., trade name Adsorbent Resin, made by Hokuetsu Carbon Industry Co., Ltd.) which can be used in about the same manner as in the case of the active carbon or the ion exchange resin. In the middle of this purification step or after this step, the aqueous acrylamide solution may be subjected to the above-mentioned concentration treatment, and reconcentration may be carried out.
In the present invention, when acrylamide is prepared by bringing acrylonitrile into contact with water in the presence of a copper-based catalyst to hydrate acrylonitrile, a compound having an active methylene group and an acidic group in one molecule or a salt of the compound is allowed to be present in the synthetic reaction system. The active methylene group is a methylene group having the formula of X-CH 2 -Y wherein each of X and Y is an electron attractive group such as NO 2 , CN, COR, COAr, CONHR, CONHAr, CO 2 R, CO 2 H, SO 2 , S, Ar and quaternary pyridinium, wherein R is an alkyl group and Ar is an aryl group, as described in Organic Reactions, John Wiley & Sons, Inc, Vol. 15, p. 222-223 (1967).
The compound which can be used in the present invention has the acidic group in addition to the above-mentioned active methylene group, and examples of the acidic group include a carboxylic group, a sulfonic group, a sulfinic group, a phosphonic group and a phosphinic group. Among these acidic groups, the carboxylic group and the sulfonic group which have the function as the acidic group also correspond to X and Y of the above-mentioned formula. Hence, the compound in which each of X and Y is the carboxylic group or the sulfonic group does not have to possess the acidic group. This kind of compound is preferable, because it conveniently has a simple structure and is easily available.
Furthermore, salts of these acidic groups, for example, sodium salts and the like can also be used. Examples of the compound in which X and Y each is also the acidic group include malonic acid, malonic monoester, malonic acid amide, cyanoacetic acid, cyanoacetic acid amide, acetoacetic acid, acetaldehydesulfonic acid, acetonesulfonic acid, sulfoacetic acid, sulfoacetic ester and sulfoacetic acid amide.
Among these compounds, α-substituted acetic acids in which the α position carbon of acetic acid is replaced with the above-mentioned functional group X or Y, i.e., malonic acid, malonic monoester, cyanoacetic, acid and the like are particularly preferable, because they are effective and easily available.
No particular restriction is put on the content of the compound, but in order to improve the sufficient water solubility and the molecular weight characteristics of the acrylamide polymer and in order to inhibit the excessive load of a purification step, the content of the compound is usually in a range of from 10 to 10,000 ppm, preferably 50 to 5,000 ppm based on the weight of a reaction solution.
As a technique of allowing the compound to be present in the reaction system, there are a way of dissolving the compound in material water or material acrylonitrile and then adding the dissolved compound, a way of dissolving the compound in a small amount of water, and a way of directly introducing the compound to the reactor or the reaction solution.
Furthermore, the compound having the active methylene group and the acidic group in one molecule or the salt of the compound can be added to a reaction solution obtained by the hydration reaction or a concentrated aqueous solution containing acrylamide in place of the reaction system, and this procedure is also a preferable embodiment.
In the present invention, the compound added to the synthetic-system can be removed by bringing the compound into contact with an anion exchange resin in the purification step. No particular restriction is put on the kind of anion exchange resin, but a weakly basic or a medially basic anion exchange resin can be preferably used. Examples of the anion exchange resin include microporous type weakly basic resins such as Lewatit MP62 (trade name, made by Bayer AG), Diaion WA20 (trade name, made by Mitsubish Chemical Industries, Ltd.) and Dowex 66 (trade name, made by Dow Chemical Co.), a gel type weakly basic resin such as Lewatit OC1059 (trade name, made by Bayer AG), gel type medially basic resins such as Lewatit MP64 (trade name, made by Bayer AG) and Amberlight IRA68 (trade name, Japan Organo Co., Ltd.), and a microporous type medially basic resin such as Dowex WRG2 (trade name, made by Dow Chemical Co.). These commercially available resins can be used after sufficiently washed with water, but it is preferable that they are subjected to a pretreatment with a dilute alkali, washed with water, and then used. With regard to a strongly basic anion exchange resin, its regeneration is difficult, and during the feed of the solution, acrylamide itself partially hydrolyzes to form acrylic acid, so that the exchange capacity of the resin noticeably deteriorates, and acrylamide is liable to polymerize between resin layers. Nevertheless, the strongly basic anion exchange resin is also usable.
The ion exchange resin can be used as a fixed layer such as a filling layer to continuously come in contact with an aqueous acrylamide solution and to purify the same, or the resin can be utilized in a batch system. However, the employment of the former is desirable, because of a good purification efficiency, an easy operation and the like. When the thus obtained acrylamide is homopolymerized or copolymerized with another comonomer, an acrylamide polymer having a remarkably improved water solubility and a sufficiently high molecular weight can be obtained.
Next, a high-molecular weight acrylamide polymer which can be used as a flocculant can be prepared as follows.
Acrylamide can be used singly or together with another vinyl polymerization type comonomer. Examples of the comonomer include acrylic acid, methacrylic acid and water-soluble salts thereof; alkylamino alkyl esters of acrylic acid and methacrylic acid and quaternary ammonium derivatives thereof; N-(dimethylaminopropyl)methacrylamide and quaternary ammonium derivatives thereof; vinyl acetate; and acrylonitrile. The mixing ratio of the comonomer to acrylamide is usually 100 mols or less, preferably 50 mols or less based on 100 mols of acrylamide.
The polymerization of acrylamide and the comonomer is carried out by a well-known manner such as aqueous solution polymerization or emulsion polymerization. Next, reference will be made to a typical procedure of the aqueous solution polymerization which has been used most extensively.
The total concentration of acrylamide and the comonomer is usually in a range of from 5 to 60% by weight. As a polymerization initiator, there can be used peroxides such as potassium persulfate, ammonium persulfate, hydrogen peroxide and benzoyl peroxide; azo-based free radical initiators such as azobisisobutyronitrile, 2,2'-azobis(4-amidinopropane) dihydrochloride and 4,4'-azobis(sodium 4-cyanovalerianate); and the so-called redox catalysts using the above-mentioned peroxides and reducing agents such as sodium bisulfite, triethanolamine and ammonium ferrous sulfate.
In the case that the total concentration of acrylamide and the comonomer is 15% by weight or more and the molecular weight of the obtained polymer is as high as 10,000,000 or more, a process involving heat insulating polymerization is usually employed, because it is difficult to control the temperature of the polymerization reaction by cooling or the like.
In this case, the temperature of the polymerization system rises by polymerization heat together with the progress of the polymerization. The preferable temperature at the start of the polymerization is often selected within a range of from -5° to 40° C., and the temperature at the end of the reaction reaches, for example, a high temperature of from 55° to 100° C.
In order to obtain a molecular weight of 10,000,000 or more, particularly a high-molecular weight of about 15,000,000, the total concentration of acrylamide and the comonomer, the kind and concentration of polymerization initiator to be used and the reaction temperature are contrived. Also in order to control the content of unreacted acrylamide to a trace amount of 0.2% by weight or less, a similar contrivance is made. In particular, many methods of using two or more kinds of polymerization initiators at different temperatures have been suggested and practiced.
The acrylamide polymer obtained by the above-mentioned polymerization reaction is a water-containing gel, i.e., a rubbery gel containing water substantially as it is which has been used to form an aqueous solution of acrylamide and the comonomer. In general, for the purpose of obtaining a dry powder product, a treatment such as the extraction of water, dehydration by heating and drying, or the crushing or grinding of the water-containing gel or the dry gel is carried out. Prior to this treatment or in the middle of the treatment, caustic soda may be kneaded with the water-containing gel, followed by heating, to convert part of amide groups into carboxyl groups, thereby chemically modifying the acrylamide polymer.
In accordance with the above-mentioned procedure, a acrylamide polymer having a high-molecular weight can be formed, the unreacted monomer can be decreased, and the polymer can be converted into the dry powder. In a certain case, however, as a result of the chemical modification, the sparingly water-soluble polymer is often formed and it tends to lose value as a commercial product such as a flocculant.
In order to solve this problem, a manner of adding an insolubilization inhibitor, a manner of using a specific polymerization initiator, or a manner of drying the water-containing gel under specific conditions is carried out before, while or after the polymerization reaction.
A process for preparing acrylamide according to the present invention summarily comprises the hydration reaction, the distillation operation, the various purification treatments and other additional steps as described above, and the obtained acrylamide can be fed to the manufacture of the above-mentioned high-molecular weight acrylamide polymer.
Next, the present invention will be described in more detail with reference to examples, but the scope of the present invention should not be limited to these examples.
EXAMPLE 1
Preparation of Acrylamide
Acrylonitrile was subjected to a hydration reaction in the presence of a copper-based catalyst by the following procedure to obtain acrylamide.
Catalyst for hydration reaction
A Raney copper alloy having a granular size of 80 mesh or less was developed with caustic soda, and then washed to prepare a Raney copper catalyst. During the preparation and in subsequent handling, the contact of the catalyst with a gas containing oxygen such as air was avoided.
Catalytic hydration reaction
400 g of the above-mentioned catalyst was placed in a SUS reactor having a volume of about 2 liters equipped with a stirrer and a catalyst separator therein, and acrylonitrile and water from which dissolved oxygen was beforehand removed by the use of a nitrogen gas were then fed at flow rates of 600 g/hr and 900 g/hr, respectively, and a reaction was carried out at 120° C. Afterward, malonic acid was added to the solution so that the concentration of malonic acid might be 150 ppm to the solution. The reaction solution was stirred together with a catalyst to become a suspension, and this suspension was then passed through the catalyst separator to take out the substantially catalyst-free solution from the reactor. This reaction was continued for 3 days.
Concentration
The obtained reaction solution was concentrated under reduced pressure by a batchwise, technique so that the total amount of unreacted acrylonitrile and a part of unreacted water were distilled off, thereby obtaining an aqueous acrylamide solution having a concentration of about 50% by weight. The thus obtained aqueous acrylamide solution contained copper.
Copper removal treatment
A glass column was filled with 150 ml of a strongly acidic cation exchange resin Lewatit SP112 (trade name, made by Bayer AG) which was made an H type by a pretreatment with dilute hydrochloric acid in accordance with a conventional procedure, and the aqueous acrylamide solution obtained by the above-mentioned concentration treatment was then passed through the glass column at 900 ml/hr. In the obtained solution, a copper content was 0.01 ppm or less, and a pH was in the range of 3.5 to 4.0.
Additive removal treatment
A glass column was filled with 150 ml of a weakly basic anion exchange resin Lewatit MP62 (trade name, made by Bayer AG) which was made an OH type by a pretreatment with dilute caustic soda in accordance with a conventional procedure, and the aqueous acrylamide solution obtained by the above-mentioned copper removal treatment was then passed through the glass column at 900 ml/hr. In the obtained solution, malonic acid was not detected, and a pH was in the range of about 6.5.
Preparation of acrylamide polymer:
The aqueous acrylamide solution obtained by the above-mentioned procedure was polymerized in the following procedure to obtain an acrylamide polymer.
Water was added to the aqueous acrylamide solution so that its concentration might be 20% by weight, and 500 g of the aqueous acrylamide solution was then placed in a 1 l polyethylene container. Afterward, nitrogen was blown into the solution to remove dissolved oxygen therefrom, while a solution temperature was maintained at 18° C., and the solution was then immediately poured into a foamed styrol heat insulating block.
Next, 200×10 -6 mpm (a molar ratio to acrylamide) of 4,4'-azobis(sodium 4-cyanovalerianate), 200×10 -6 mpm of dimethylaminopropionitrile and 80×10 -6 mpm of ammonium persulfate were each dissolved in a small amount of water, and they were then promptly poured into the above-mentioned solution in this order. To these reagents, a nitrogen gas was beforehand blown, and during, before and after the introduction of the these reagents, a small amount of the nitrogen gas was blown into the above-mentioned polyethylene container to prevent an oxygen gas from getting into the solution. After the introduction of the reagents and an induction period of several minutes, it was observed that the temperature in the polyethylene container rose, and so the feed of the nitrogen gas was stopped. When the temperature reached a peak of about 70° C. after about 100 minutes, the polyethylene container was taken out from the heat insulating block, immersed in water at 97° C. for 2 hours, and then immersed in cold water to cool it.
The thus obtained water-containing gel of an acrylamide polymer was divided into small masses, and they were then mashed by chopper, dried with hot air at 100° C. for 2 hours, and then ground by a high-speed rotary blade grinder to obtain an acrylamide polymer in the state of a dry powder. Furthermore, this polymer was put through a sieve to collect the polymer having a size of 32 to 42 mesh as polymer samples for a subsequent test. The water contents of the polymer samples were determined on the basis of a weight reduction by overnight drying with hot air at 125° C., and as a result, the water contents of these polymer samples were all about 10% by weight.
Tests of acrylamide polymer:
The water solubility and the standard viscosity of the polymer samples obtained by the above-mentioned procedure were measured as follows.
Water solubility
The water solubility was measured as follows. 600 ml of water was put into a 1 liter beaker, and 0.66 g (pure content=0.6 g) of the polymer sample was added, while water was stirred by a stirring blade having a certain shape. Next, stirring was carried out at 400 rpm for 2 hours, and the obtained solution was filtered through a wire gauze of 150 mesh. Thus, the water solubility was judged from the amount of insolubles and filtering characteristics. That is to say, evaluation was made as follows. ⊚ means the solution which could be completely dissolved; ◯ means the solution which could be nearly completely dissolved; Δ means the solution in which the insolubles were present but they could be separated by filtration; and X means the solution in which the passage of a filtrate was slow and the filtration of the insolubles was practically impossible.
If having a molecular weight of about 15,000,000 or more and a solubility of ◯ or higher, the acrylamide polymer has so high a quality as to be used as a flocculant. The acrylamide polymer having the solubility of Δ can be used as a paper agent, but it is not desirable as the flocculants. The acrylamide polymer having the solubility of X is not usable in most uses, and it has no commercial value.
Molecular weight
The molecular weight was determined as follows. Some aqueous acrylamide polymer solutions having different concentrations were prepared by the use of the filtrate obtained by the same procedure as described above, and 1 mol of sodium nitrate was added to each aqueous acrylamide polymer solution. Afterward, an intrinsic viscosity was measured by the use of a capillary viscometer, and the molecular weight was calculated as follows.
Intrinsic viscosity=3.73×10 -4 ×[weight average molecular weight] 0 .66
The filtrate obtained in the above-mentioned solubility test was an aqueous polymer solution having a concentration of 0.1% by weight in the case that the water solubility was good. One mol of sodium chloride was added to this aqueous polymer solution, and a viscosity was measured at a rotor revolution of 60 rpm at 25° C. by the use of a BL viscometer and a BL adapter (standard viscosity). The standard viscosity obtained by such a procedure was used as a value concerned with the molecular weight, and so it was also used in this example.
Evaluation results of polymer
According to evaluation made in the above-mentioned manner, the water solubility of the obtained polymer was good and could be judged to be ⊚, and its standard viscosity was 6.0 cps (estimated molecular weight=17,200,000).
EXAMPLES 2 TO 10
The same procedure as in Example 1 was carried out except that in a catalytic hydration reaction of Example 1, the amount of malonic acid to be added to a material solution was changed and malonic acid was replaced with other additives as shown in Table 1, and that in an additive removal treatment, resins were changed as shown in Table 1. In acrylamides obtained in the respective examples, the additives were not detected. According to this evaluation, the finally obtained acrylamide polymers were excellent in water solubility and had sufficient molecular weights, as in Example 1.
COMPARATIVE EXAMPLES 1 TO 3
The same procedure as in Example 1 was carried out except that in a catalytic hydration reaction of Example 1, malonic acid to be added to a material solution was not added, and that other additives shown in Table 1 were used. In acrylamides obtained in the respective comparative examples, the additives were not detected, but the water solubility of any finally obtained acrylamide polymers was not satisfactory.
COMPARATIVE EXAMPLE 4
The same procedure as in Example 1 was carried out except that in place of malonic acid, m-cresol was added so that its concentration might be 100 ppm. In the obtained acrylamide, the additive was detected, and so any polymerization evaluation was not done.
COMPARATIVE EXAMPLE 5
The same procedure as in Example 1 was carried out except that in a catalytic hydration reaction of Example 1, as an additive, m-cresol was added so that its concentration might be 100 ppm to a material solution, and that in an additive removal treatment, a strongly basic anion exchange resin MP 500 was used. In obtained acrylamide, the additive was not detected. The water solubility of the finally obtained acrylamide polymer was not satisfactory.
COMPARATIVE EXAMPLE 6
The same procedure as in Example 1 was carried out except that in a catalytic hydration reaction of Example 1, as an additive, m-cresol was added so that its concentration might be 1,000 ppm to a material solution, and that in an additive removal treatment, a strongly basic anion exchange resin MP 500 was used. However, during the additive removal treatment, an aqueous acrylamide solution was inconveniently polymerized in a resin layer.
COMPARATIVE EXAMPLE 7
The same procedure as in Example 1 was carried out except that in a catalytic hydration reaction of Example 1, as an additive, urea was added so that its concentration might be 600 ppm to a material solution. In obtained acrylamide, the additive was not detected. The water solubility of the finally obtained acrylamide polymer was not satisfactory.
COMPARATIVE EXAMPLE 8
The same procedure as in Example 1 was carried out except that in a catalytic hydration reaction of Example 1, glycine was added so that its concentration might be 750 ppm to a material solution. However, the hydration reaction of acrylonitrile scarcely proceeded.
TABLE 1__________________________________________________________________________ Removal of Evaluation of Amount Conversion Additive polymer of of Acryl- Conc. of Standard Additive onitrile Used Additive Solu- viscosity Additive (ppm) (%) Resin (ppm) bility (cps)__________________________________________________________________________Example 1 Malonic Acid 150 60.0 MP62 N.D. ⊚ 6.0 (Note 1) (Note 2)Example 2 Malonic Acid 1000 58.9 MP62 N.D. ⊚ 5.9Example 3 Malonic Acid 150 60.2 OC1059 N.D. ⊚ 6.0Example 4 Sodium 870 58.6 MP62 N.D. ◯ 5.8 MalonateExample 5 Cyanoacetic 160 60.1 MP62 N.D. ⊚ 6.0 AcidExample 6 Cyanoacetic 160 59.3 OC1059 N.D. ◯ 6.1 AcidExample 7 Cyanoacetic 160 61.1 WA20 N.D. ◯ 6.0 AcidExample 8 Acetoacetic 200 59.9 MP62 N.D. ◯ 5.9 AcidExample 9 Acetosulfunic 200 56.4 MP62 N.D. ◯ 5.8 AcidExample 10 Sulfoacetic 200 57.1 MP62 N.D. ◯ 5.8 Acid AmideComp. Ex. 1 None 0 49.8 MP62 N.D. X Measurement was impossibleComp. Ex. 2 Acrylic Acid 140 60.1 MP62 N.D. Δ 5.8Comp. Ex. 3 Acetic Acid 120 52.2 MP62 N.D. X Measurement was impossibleComp. Ex. 4 m-cresol 100 56.4 MP62 80Comp. Ex. 5 m-cresol 100 57.2 MP500 N.D. Δ 6.0Comp. Ex. 6 m-cresol 1000 60.0 MP500 Polymerized while fedComp. Ex. 7 Urea 600 44.4 MP62 N.D. X Measurement was impossibleComp. Ex. 8 Glycine 750 Reaction did not occur__________________________________________________________________________ (Note 1): N.D. means that the additive was not detected. (Note 2): The acrylamide polymer of Example 1 estimates as a molecular weight of about 17,200,000.
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A process for preparing acrylamide is disclosed herein which comprises subjecting acrylonitrile to a hydration reaction in the presence of a copper-based catalyst, said process comprising the step of allowing a compound having an active methylene group and an acidic group in one molecule or a salt of the compound, for example, malonic acid, cyanoacetic acid or its salt to be present in a reaction system. According to the hydration reaction, it is possible to inhibit the secondary formation of impurities which cannot be heretofore removed, without any deterioration of a catalyst activity, and acrylamide can be obtained which is useful as a material for the manufacture of a high-molecular weight flocculant having a sufficiently large molecular weight and a good water solubility.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the invention
[0002] The present invention relates generally to electronic neural networks and, more particularly, to a neural processing module that preferably resides on a single “chip” and which achieves high computation rates (usually defined as the number of floating point operations per second), which operates relatively fast, but consume relatively little power and occupies relatively little space, which may be scaled in a planar or massively parallel, stacked arrangement to handle more inputs, achieve greater processing rates, or both, and which achieves its synaptic connections through binary weights that are maintained “off chip” so that the neural processing module may implement a variety of algorithms in different neural network applications.
[0003] 2. Description of the Prior Art and Related Information
[0004] Interest in neural networks has increased because of their theoretical potential to solve problems that are difficult or even impossible to accomplish with conventional computers. Earlier researchers noted, for example, that “[t]he collective behavior of neural network systems has demonstrated useful computation properties for associative memory functions, fault-tolerant pattern recognition, and combinatorial optimization problem solving.” A. P. Thakoor, A. Moopenn, J. Lambe, and S. K. Khanna, “Electronic hardware implementations of neural networks,” Applied Optics, Vol. 26, page 5085, Dec. 1, 1987.
[0005] Early neural network research relied on software simulations performed with digital computers based on sequential Von Neuman architectures—“The study of the dynamics, learning mechanisms, and computational properties of neural networks has been largely based on computer software simulations.” Id. It has long been recognized, however, that neural network hardware was needed to “provide the basis for development of application-specific architectures for implementing neural network approaches to real-life problems.” Id. The many simple, interconnected processors of a neural network implemented in hardware, or electronic neural network, allow for fast parallel processing, but “designing hardware with a large number of processors and high connectivity can be quite difficult.” C. Lindsey and T. Lindblad, “Review of Hardware Neural Networks, A User's Perspective.” Physics Dept.—Frescati, Royal Institute of Technology Frescativägen 24 104 05 Stockholm, Sweden, 1995.
[0006] Electronic neural networks, however, have already been implemented in digital, analog, and hybrid technologies.
[0007] Digital architectures are desirable because “digital technology has the advantage of mature fabrication techniques, weight storage in RAM, and arithmetic operation exact within the number of bits of the operands and accumulators. From the users viewpoint, digital chips are easily embedded into most applications. However, digital operations are usually slower than in analog systems, especially in the weight×input multiplication . . . ” C. Lindsey and T. Lindblad, id. Processing speed, power consumption, and size (or density) are often critical concerns. These inventors do not know of any digital neural networks that provide sufficiently low power consumption and density to reasonably accomplish the massively parallel processing needed, for example, to perform real-time pattern recognition or feature matching. A single digital neuron is faster than an analog neuron; however, when many digital neurons are combined the size becomes larger and the propagation time between neurons will dominate. Power dissipation is also larger in a digital context.
[0008] Analog neurons are smaller and use less power than digital approaches, but are slower and subject to certain complications. For example, “[c]reating an analog synapse involves the complications of analog weight storage and the need for a multiplier [that is] linear over a wide range.” C. Lindsey and T. Lindblad, id.
[0009] “Hybrid” neural networks combine the “best” of the digital and analog architectures—“Typically, the external inputs/outputs are digital to facilitate integration into digital systems, while internally some or all of the processing is analog.” C. Lindsey and T. Lindblad, id. One of the hybrid neural networks discussed in the Lindsey/Lindblad article had 70 analog inputs, 6 hidden layers and 1 analog output with 5-bit digital weights, and achieved a “feed-forward processing rate [of] an astounding 20 ns, representing 20 GCPS [Billion Connections Per Second] . . . ”
[0010] The Thakoor et al. article reference above discusses another hybrid neural network (hereafter “JPL network”) which has six neurons and thirty-six synapses and which uses analog inputs and digitally programmable weights. The hybrid architecture of the JPL network allegedly offers a number of advantages by using “high-density random access digital memory to store a large quantity of information associated with the synaptic weights while retaining high-speed analog neurons for the signal processing.” Id. at 5089. The authors further note that by using “programmable” synapses, “[t]he hardware requirements and complexity are greatly reduced since the full interconnections of the neurons are no longer required.” Id.
[0011] The JPL authors recognized that “a hybrid neurocomputer can be easily expanded in size to several hundred neurons.” Id. They did not, however, propose any realistic way of implementing a network with thousands of inputs or of implementing a network of any size that makes maximum use of its neurons.
[0012] There remains a need, therefore, for a low power, high density, neural processing module which achieves high computation rates, which may be scaled to achieve greater processing rates and to handle more inputs, and which may be used in an electronic neural networks that simplifies the implementation of a particular function by maintaining the weights or synaptic connections “off chip” by using, for example, a chip-in-a-loop arrangement that is controlled by a conventional computer.
SUMMARY OF INVENTION
[0013] The present invention resides in a neural processing module which combines a weighted synapse array that performs “primitive arithmetic” (products and sums) with an innovative weight change architecture and an innovative data input architecture which collectively maximize the use of the weighted synapse array. In an image recognition context, the neural processing module dynamically reconfigures incoming image signals against preexisting weights and performs a corresponding successions of convolutions (products and sums) during each image frame.
[0014] In more detail, the neural processing module of the present invention achieves extremely high computation rates with lower power and lower area consumption than previously possible by providing a high speed, low power, small geometry array of analog multipliers, and by using such array as continuously as possible. The preferred neural processing module uses its synapse array almost continuously by uniquely combining:
[0015] (1) a synapse array of analog synapse cells (e.g. multipliers) and programmable synapses that receives analog data and digital weights and multiplies the analog data by the analog equivalent of the digital weights at a “calculation rate” (e.g. 4 MHz);
[0016] (2) a means for rapidly loading the programmable synapses with the digital weights (determined externally, for example, by a microprocessor) at the beginning of each frame and in advance of using the synapse array; and
[0017] (3) a switching means for receiving frames of periodic input signals at an “arrival rate” that is slower than the calculation rate (e.g. 1000 Hz), for rapidly creating a plurality of input signal permutations from the periodic input signals at a “permutation rate” that is greater than the arrival rate and preferably at or greater than the calculation rate (e.g. 4 MHz), and for feeding each successive input signal permutation to the synapse array at or near the calculation rate.
[0018] The invention can be regarded as an electronic neural processing module for convolving a first group of signals with a second group of signals, comprising: means for receiving a first group of signals; switching means for receiving a second group of signals and for creating successive groups of permutated signals from the second group of signals before a next group of second signals arrives; analog multiplying means for simultaneously multiplying each signal in the first group of signals with each signal in each successive group of permutated signals to form a plurality of products; and means for accumulating the plurality of products to produce a convolution output.
[0019] The invention can also be regarded as an electronic neural network image recognition system comprising: means for receiving a plurality of weights; means for receiving successive groups of image signals (the image template) at a predetermined frame rate; switching means for creating successive groups of image permutation signals from each group of image signals [the image template] before receiving a subsequent group of image signals; a weighted synapse array of analog synapse cells that simultaneously perform a plurality of calculations at a calculation rate, wherein the calculation rate is greater than the frame rate, the plurality of calculations comprising the multiplying of each weight with each signal in each group of image permutation signals to form a plurality of products; and means for summing the plurality of products to produce a convolution output with a value that represents a correlation quality between the weights and each successive group of image permutation signals.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] The just summarized invention may best be understood with reference to the Figures of which:
[0021] [0021]FIG. 1 shows a weighted synapse array 200 that might be used in a neural processing module (NPM) 100 according to the present invention;
[0022] [0022]FIG. 2 is a block diagram of a neural processing module (NPM) 100 which makes maximal use of an N×N synapse array 200 according to a preferred embodiment of the present invention;
[0023] [0023]FIG. 3 is a block diagram of a conventional pattern recognition system;
[0024] [0024]FIG. 4 is a block diagram of a pattern recognition system which uses at least one NPM 100 according to the present invention;
[0025] [0025]FIG. 5 shows the preferred NPM 100 for use in a pattern recognition system like that of FIG. 4; and
[0026] [0026]FIG. 6 is a more detailed block diagram of the digital logic 500 and weight loading means 400 of FIG. 5.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0027] [0027]FIG. 1 shows a weighted synapse array 200 that might be used in a neural processing module (hereafter NPM) 100 according to the present invention (see e.g. FIG. 4). The synapse array 200 of FIG. 1 is only 8×8 so that its components and connections are easily understood. The array used in the NPM 100 may be larger or smaller than 8×8. The preferred array 200 is 64×64.
[0028] Regardless of its size, the synapse array 200 contains a plurality of synapse cells 201 , each of which contains analog circuitry that forms the product of a first signal (e.g. a weight W 1 , W 2 , W 3 , etc . . . ) and a second signal (e.g. an input signal I 1 , I 2 , I 3 , etc . . . ). Each synapse cell 201 preferably contains a digital to analog converter (DAC) 202 so that a conventional digital computer maintains the weights “off-chip” and loads the weights into the DACs 202 of the synapse cells 201 as explained further below.
[0029] When the DAC 202 of each synapse cell 201 receives a digital weight W 1 -W 8 , it converts the digital weight to an analog weight quantity such as charge. When the synapse cell 201 subsequently receives an analog input signal I 1 -I 8 , it multiplies the analog input signal by the analog weight quantity, and produces an analog output quantity such as current. The products of the synapse cells 201 are then summed together by ordinary current summation to provide a sum of the products.
[0030] As should now be clear, each synapse cell 201 is an analog multiplier and the overall synapse array 200 is a two-dimensional array of analog multipliers whose products (currents) are added together through current summation.
[0031] The construction and operation of a weighted synapse array 200 was first disclosed in an article published by researchers from Jet Propulsion Laboratory, entitled “Electronic hardware implementations of neural networks,” California Institute of Technology, published in Applied Optics, Vol. 26, page 5085, Dec. 1, 1987. The JPL authors recognized that the synapse array 200 could be expanded to “several hundred neurons”, but they did not contemplate a neural processing module 100 that combines the synapse array 200 with a unique signal inputting architecture and a unique weight updating architecture that permits the array to have thousands of synapse cells (“neurons”) which are used at maximal efficiency.
[0032] Analog Versus Digital
[0033] These inventors made critical observations regarding analog and digital multipliers. The first consideration was speed. Here, digital wins because a digital multiplier is generally faster than an analog multiplier. In particular, the synapse cells 201 operate as analog multipliers with a typical latency of about 250×10 −9 seconds (250 nS). By comparison, faster speeds were already being achieved in digital chips that were commercially available in 1988, nearly ten years before this invention:
Features MIPS R3010 Weitek 3364 TI 8847 Clock cycle time (ns) 40 50 30 Power (watts) 3.5 1.5 1.5 Cycles/mult 5 2 3 Total mult time (ns) 200 100 90
[0034] Hennessy, John L. & Patterson, David A. 1996 Computer Architecture A Quantitative Approach. 2nd ed. San Francisco: Morgan Kaufmann Publishers, Inc., p. A-61.
[0035] A reference to more recent technology claims that digital multipliers are available “with a latency of less than 2.6 nanoseconds @ 10.5 Watts and a layout area of 13 mm 2 .” Bewick, Gary W. 1994 “Fast Multiplication: Algorithms and Implementation,” Stanford University, Technical Report No. CSL-TR-94-617.
[0036] Power consumption is as important an issue as speed. Here, analog multipliers come out ahead of digital multipliers. In particular, a synapse array 200 having 4096 synapse cells 201 only burns about 50 milliwatts, whereas only one (1) of the digital multipliers listed above burns 1.5, 3.5, or 10.5 watts.
[0037] Size was the final issue considered. Here again, analog multipliers come out ahead of digital multipliers because the number of FETs required for an 8-bit analog multiplier is 32, and the number of FETs for a digital multiplier is typically 2N+2 registers, where each register requires 20 FETs for a total of 360 FETS for N=8 (additional FETs required for higher speed).
[0038] Analog multipliers are slower and apparently undesirable. These inventors determined, however, that analog's speed detriments are outweighed by its relatively larger size and power consumption advantages. An example may help. An analog multiplier that is 10×slower than its digital counterpart, might use 1,000 times less power and occupy 100 times less space. If so, it is possible to construct a massively parallel arrangement of 10×as many analog multipliers that perform the same number of multiplications per second as the smaller number of digital multipliers, but at greatly reduced power (100×less) and space consumption (10×less). The benefits of analog are further enhanced if the synapse array 200 is used as many times as possible between each successive group of periodic input signals.
[0039] Analog is clearly desirable (if used according to the present invention), but the data processing world is largely digital. A key concern, therefore, is providing a device with a plurality of analog multipliers that has means for receiving input signals, weights, or both, via a digital interface. These inventors are unaware of any existing technology that has effectively accomplished this feat in the context of a maximally used array.
[0040] The NPM Generally
[0041] [0041]FIG. 2 is a block diagram of a neural processing module (NPM) 100 which makes maximal use of an N×N synapse array 200 according to a preferred embodiment of the present invention. The NPM 100 generally comprises the synapse array 200 , an input switching means 300 that receives periodic input signals 110 , and a digital weight loading means 400 .
[0042] The periodic input signals 110 may be characterized by an “arrival rate” and the synapse array 200 may be characterized by a “calculation rate.” These rates are usually very different. For example, the arrival rate of the periodic input signals might be only 30 times per second, or 30 Hz, whereas the calculation rate of the synapse array 200 might be 4,000,000 calculations per second, or 4 MHz.
[0043] The present invention takes unique advantage of the disparity between the calculation rate of the synapse array 200 and the arrival rate of the periodic input signals 110 . In particular, an NPM 100 according to the present invention repetitively uses the synapse array 200 for each successive group of periodic input signals (often called a “frame”) by:
[0044] (1) loading N digital weights 410 into the DAC's 202 of the synapse array 200 ;
[0045] (2) rapidly creating a plurality of input signal permutations 310 ; and
[0046] (3) providing the synapse array with those input signal permutations 310 prior to the arrival of the next group of period input signals 110 .
[0047] The input switching means 300 that receives the periodic input signals 110 and creates the signal permutations 310 is any structure that can rearrange the periodic input signals 110 and, preferably, can do so at the calculation rate of the synapse array 200 .
[0048] The preferred input switching means 300 is a “crossbar” having N inputs that are selectively, simultaneously multiplexed to N outputs at a very fast rate that can “keep up” with the array's calculation rate. A detailed description of crossbars is unnecessary because various arrangements are well known to those of ordinary skill in the art.
[0049] The digital weight loading means 400 can be of any desired construct that can rapidly load the digital weights into the DAC's 202 and still provide sufficient time to repetitively use the synapse array 202 with a plurality of permutations 310 before the arrival of the next group of periodic input signals 110 .
[0050] The output 210 of the synapse array 200 can be anywhere from one line to N lines, depending on whether the output lines are summed together on-chip or off-chip (preferred).
[0051] The NPM 100 is beneficially modular such that a system may have only one NPM 100 ; many NPMs that are provided in a flat, board mounted arrangement, or many NPMs that are provided in a stacked arrangement within a Z-type module comparable to that disclosed in U.S. Pat. No. 5,235,672 which patent is assigned to the assignee of this application and is entitled “HARDWARE FOR ELECTRONIC NEURAL NETWORK.”
[0052] The NPM 100 of FIG. 2 is also a general purpose chip that may be used in a variety of applications because the digital weights are controlled off-chip. The NPM 100 is particularly suited to a pattern recognition, however, because it can rapidly perform “inner product” convolution with a plurality of image permutations and a pre-existing template of weights. Accordingly, the remainder of this specification will describe the preferred NPM 100 with an emphasis on pattern recognition.
[0053] Pattern Recognition
[0054] In a pattern recognition system, the periodic input signals are image signals 110 that are obtained from an external image source ISO such as a photosensor array, or a video signal, and the weights correspond to an image “template” that the system tries to locate within the image data. The periodic image signals generally arrive in frames that are refreshed at a fixed frequency that is relatively slow when compared to the calculation capability of the synapse array 200 .
[0055] The purpose of this invention is to maximize the use of the synapse array 200 . If the synapse array 200 were provided with only one set of image signals per frame in an ordinary manner, it would accomplish its arithmetic task almost immediately and then do nothing during the remainder of each successive frame. The synapse array 200 has a dramatic amount of “free time.” The present invention takes advantage of the free time by creating and using image signal permutations during each frame.
[0056] The frame rate (corresponding to the “data arrival” rate discussed above) might be as slow as 30 Hz in the case of video signals that are displayed on a conventional televisions, or as fast as 1000 Hz in the case of special photosensor circuits that are designed for commercial or military applications. In either case, the frame rate is substantially lower than the maximum calculation rate of the synapse array 200 . Stated conversely, the synapse cells 201 can perform many, many calculations (products and sums) before a new image frame arrives.
[0057] Some numbers may clarify this concept. The synapse cells 201 of a typical synapse array 200 require about 250 nanoseconds (250×10 −9 seconds) to multiply an analog input representing the brightness of an image pixel (voltage or current) by an analog equivalent of a digital weight (charge or voltage). An analog multiplication that takes 250 nanoseconds is very slow relative to digital multipliers, the faster of which have a latency of less than 2.6 nanoseconds. Even at such a “slow” rate, however, a synapse array 200 that is used maximally could accomplish nearly 4 million multiplies per second, or 4 Mhz, which is about 4,000 times faster than the image generated by CCD array running at 1000 Hz and is about 133,333 times faster than the 30 Hz frame rate of an image generated by a television broadcast and.
[0058] [0058]FIG. 3 is a block diagram of a conventional system that clarifies the benefits of using the present invention in the context of pattern recognition system. In this case, periodic image signals from an external image source 150 are provided to a main processor 160 that divides the image signals into manageable components and then passes each component to one of several coprocessors P 1 , P 2 , P 3 which separately endeavor to find a match. There are several problems with this approach. First, there is an I/O bottleneck because a substantial amount of data must move back and forth between the main processor 160 and the plurality of coprocessors P 1 , P 2 , P 3 . Second, it is not generally obvious how to divide the image, the template, or both. The system may literally split up the “target” portion of the image and pass part to one co-processor and part to another co-processor, such that neither finds the target.
[0059] [0059]FIG. 4, on the other hand, shows a pattern recognition system which uses at least one NPM 100 according to the present invention. Here, the NPM 100 receives the periodic image signals [I] 110 from the external image source 150 via its input switching means 300 , and within the time span of a single frame, rapidly rearranges those image signals into a succession of image signal permutations, multiplies each permutation by the weights [W] that were loaded into the synapse array 200 via the weight loading means 400 under the control of an external CPU 180 , sums the products together, and outputs a corresponding successions of values on one or more outputs 210 representing the quality of each correlation. A high output value 210 indicates high correlation with the template (a match) and a low output value 210 indicates low correlation with the template (no match). The input switching means 300 uniquely rearranges the incoming image signals 110 to create any desired sequence of orientations, sizes, and distortions of the data before the arrival of the next image frame. Moreover, there is no bottleneck and there is no need to divide the image.
[0060] The Preferred NPM
[0061] [0061]FIG. 5 shows the preferred NPM 100 for use in a pattern recognition system like that of FIG. 4. The NPM 100 generally comprises a weighted synapse array 200 , an input switching means consisting of a crossbar 300 , and digital weight loading means 400 .
[0062] Here, the crossbar 300 receives 64 image signals from an external image source 150 (see FIG. 4), forms a plurality of image signal permutations 310 from the 64 image signals and successively outputs such image signal permutations 310 to the synapse array 200 . Digital logic 500 controls the crossbar 300 according to clocks and data received from the computer 180 or other external source. The crossbar 300 rearranges the incoming image signal at or near the calculation rate of the synapse array 200 .
[0063] The digital logic 500 also contains the weight loading means 40 that loads the digital weights into the DACs 202 of the synapse cells 201 via a level shifter 600 (discussed below) in accordance with the clocks and data from the external computer 180 .
[0064] [0064]FIG. 6 is a more detailed block diagram of the digital logic 500 and weight loading means 400 of FIG. 5. In this particular case, the digital weights are 8-bits each, such that all 64 digital weights nominally require 512 bit values. The digital logic 400 absorbs the large number of bit values in smaller increments. The weight loading means 400 serially clocks in only 33 bits of digital weight data (four 8-bit weights and 1 parity bit) via a shift register 410 running at 34 MHz, latches the data into the appropriate four of the sixty-four registers 430 , computes the presence or absence of a parity error. The weight loading means 400 then transfers all 64 weights to the synapse array 200 via the level shifter 600 .
[0065] The level shifter 600 permits low power operation. The digital logic 500 and external computer 180 nominally run at 5 volts, but the preferred synapse array 200 operates at a relatively low voltage level of 3.3 volts so that it uses as little power as possible. The level shifter 600 simply converts the digital weights to the voltages that are suitable for the low power operation of the synapse array 200 .
[0066] A common measure of system performance is “floating points operations per second” or FLOPS. Each synapse cell 201 can do 4,000,000 multiplies per second, or 4 megaFLOPS. A single NPM 100 can operate at 16 gigaFLOPS since the 64×64 synapse array 200 has 4096 synapse cells 201 . (4096×4,000,000 FLOPS≅16 gigaFLOPS).
[0067] Pattern Recognition System—Multilayer Embodiment
[0068] A plurality of the NPMs 100 may be “stacked” to form, for example, a 64×64×64 cube of synapse cells 201 . This provides 262,144 synapse cells 201 for convolving a 64×64 array of image signal permutations with a 64×64 array of weights.
[0069] The 64 weights associated with the synapse array 200 of one NPM 100 can be called a “weight column”. An ideal system would simultaneously update all 64 weight columns within a small fraction of an image frame. Since that was impractical, however, the preferred system updates one weight column per frame and uses the remaining 63 weight columns as part of an instantaneous template of weights that are actively convolved with the 64×64 array of incoming image signal permutations. It is possible to find a correlation with only 63 of 64 weight columns because of the fault tolerant aspects of a neural network.
[0070] Since the 64 synapse arrays 200 reside in 64 adjacent layers, the output(s) provided at the edges of the adjacent synapse arrays 200 must be bused together off-chip. The preferred synapse arrays 200 have 64 distinct outputs rather than one combined output to provide more generality. In such case, the 64 distinct outputs of each array 200 are connected to 64 intermediate buses that run transversely to the edges of the adjacent synapse arrays 200 , and the 64 intermediate busses are connected to a final bus that runs parallel to the edges of the adjacent synapse arrays 200 to form a final output.
[0071] A stack of 64 NPMs 100 can perform as many as 1 trillion floating point operations per second (1 “teraFLOP”) since a 64×64×64 array has 262,144 synapse cells 201 that can each perform four million FLOPS, or multiplies per second (262,144×4,000,000 FLOPS≅1 teraFLOP).
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A neural processing module is disclosed which combines a weighted synapse array that performs “primitive arithmetic” (products and sums) in parallel with a weight change architecture and a data input architecture that collectively maximize the use of the weighted synapse array by providing it with signal permutations as frequently as possible. The neural processing module may be used independently, or in combination with other modules in a planar or stacked arrangement.
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BACKGROUND
[0001] This invention relates to improved membranes for the separation of fluids made from polymers.
[0002] Permselective membranes for fluid separation are known and used commercially in applications such as the production of oxygen-enriched air, production of nitrogen-enriched-air for inerting and blanketing, separation of carbon dioxide from methane or nitrogen for the upgrading of natural gas streams, and the separation of hydrogen from various petrochemical and oil refining streams. Some membranes are made of materials that have high permeabilities, but exhibit low permselectivities. For certain fluid streams, one or more component or minor contaminant, such as organic solvents, may exhibit a strong interaction with the material of the membrane, which can result in the loss of performance due to plasticizing the membrane or other problems. Some membrane materials may offer resistance to this interaction with contaminants, but suffer from poor mechanical properties, resulting in membrane failure when exposed to high membrane differential pressures and high temperatures. Other materials, such as previously available polyimide polymers, are not capable of processing into membranes of the desired configuration (such as a hollow fiber membrane). A membrane with a good balance of high productivity and selectivity for the fluids of interest, and persistently good separation performance despite long-term contact with aggressive process composition, pressure and temperature conditions, and that can be processed into a wide variety of membrane configurations is highly desired.
[0003] Membranes of polyimide polymers are desirable for their chemical resistant properties. However, some commercially available polyimide polymers are low molecular weight (MW) and prone to hydrolysis. Solution spinning of these polymers results in brittle hollow fibers. Due to the poor mechanical properties of these fibers, the polyimide polymers are difficult to commercially use to produce gas separation membranes, particularly hollow fiber membranes.
[0004] The references discussed below describe separation membranes known in the art and disclose information relevant to polyimide polymer membranes. However, these references suffer from one or more of the disadvantages discussed above.
[0005] U.S. Pat. No. 4,705,540 discloses highly permeable polyimide gas separation membranes prepared from phenylene diamines having substituents on all positions ortho to the amine functions and a rigid dianhydride or mixtures thereof, specifically pyromellitic dianhydride (PMDA) and 4,4′-(hexafluoroisopropylidene)-bis(phthalic anhydride) (6FDA).
[0006] U.S. Pat. No. 4,717,393 shows that polyimides incorporating at least in part 3,3′,4,4′-benzophenone tetracarboxylic dianhydride and phenylene diamines having substituents on all positions ortho to the amine functions can be photo chemically crosslinked. Photochemical crosslinking is not considered a practical method for fabricating cost-effective gas separation membranes.
[0007] U.S. Pat. No. 4,880,442 discloses highly permeable polyimide gas separation membranes prepared from phenylene diamines having substituents on all positions ortho to the amine functions and essentially nonrigid dianhydrides.
[0008] U.S. Pat. No. 5,055,116 and U.S. Pat. No. 5,635,067 describe blends of polyimides designed to attempt to create a membrane with desirable performance properties. Polymeric blending has traditionally been thought to be problematic or result in poor mechanical properties, and limited range of fluid transport properties.
[0009] U.S. Pat. Nos. 4,532,041, 4,571,444, 4,606,903, 4,836,927, 5,133,867, 6,180,008, and 6,187,987 disclose membranes based on a polyimide copolymer derived from the co-condensation of benzophenone 3,3′,4,4′-tetracarboxylic acid dianhydride (BTDA) and a mixture of di(4-aminophenyl)methane and a mixture of toluene diamines useful for liquid separations.
[0010] U.S. Pat. Nos. 5,605,627, 5,683,584, and 5,762,798 disclose asymmetric, microporous membranes based on a polyimide copolymer derived from the co-condensation of benzophenone-3,3′,4,4′-tetracarboxylic acid dianhydride (BTDA) and a mixture of di(4-aminophenyl)methane and a mixture of toluene diamines useful for liquid filtration or dialysis membranes.
[0011] It is highly desirable to create a membrane that can be used commercially in applications such as the production of oxygen-enriched air, production of nitrogen-enriched-air for inerting and blanketing, separation of carbon dioxide from methane or nitrogen for the upgrading of natural gas streams, and the separation of hydrogen from various petrochemical and oil refining streams. The desired membranes should exhibit a resistance to interaction of the material with the process and the resulting plasticizing of the membrane. Furthermore, membranes should have superior mechanical properties to allow the use of the membranes in high differential pressure applications, and should be capable of easily processing into membranes of the desired configuration (such as a hollow fiber membrane). Thus, membranes with a good balance of high productivity and selectivity for the fluids of interest, and persistently good separation performance despite long-term contact with aggressive process composition, pressure and temperature conditions are desired.
SUMMARY
[0012] The membranes of the invention satisfy the need to have membranes that exhibit a resistance to interaction of the material with the process and the resulting plasticizing of the membrane. Furthermore, membranes of the invention have surprisingly superior mechanical properties, resulting in superior performance when exposed to high membrane differential pressures and high process temperatures. The membranes of the invention are pliable (not brittle), and are capable of processing into membranes of a wide variety of desired configurations (particularly hollow fiber membranes). The membranes of the invention have a good balance of high productivity and selectivity for the fluids of interest, and persistently good separation performance despite long-term contact with aggressive process compositions, pressure and temperature conditions.
[0013] The present invention provides a membrane for fluid separation containing an annealed polyimide polymer, wherein the annealed polyimide polymer comprises a number of first repeating units of formula (i), which is described below. Commercially available virgin polyimide polymer is subjected to an annealing process to form the annealed polyimide polymer of the current invention, which surprisingly increases the mechanical properties of the final membrane.
[0014] The first repeating units of the annealed polyimide polymer are of a formula (I):
[0015] In formula (I), R 1 is a molecular segment of a formula (A), formula (B), formula (C), or mixtures of formula (A), formula (B), and formula (C), where formula (A), formula (B), and formula (C) are:
[0016] Furthermore, in formula (I), R 2 is a molecular segment of a formula (Q), formula (S), formula (T), or mixtures of formula (Q), formula (S), and formula (T), where formula (Q), formula (S), and formula (T) are:
[0017] In formula (T) above, Z is a molecular segment of a formula (L), formula (M), formula (N), or mixtures of formula (L), formula (M), and/or formula (N), where formula (L), formula (M), and formula (N) are:
[0018] Referring to the annealed polyimide polymer discussed above, the first repeating units may alternately be of a formula (Ia), where formula (Ia) is:
[0019] In formula (Ia), R 1 is a molecular segment having a composition of formula (A), formula (B), or formula (C), or a mixture of formula (A), formula (B), or formula (C) in the first repeating units and where formula (A), (B), and (C) are those described above. 10 In another alternate embodiment of formula (Ia), the R 1 in formula (Ia) has a composition of formula (A) in about 10-25% of the first repeating units, formula (B) in about 55-75% of the first repeating units, and formula (C) in about 20-40% of the first repeating units.
[0020] In another alternate embodiment of formula (Ia), the molecular segment R 1 has a composition of formula (A) in about 16% of the first repeating units, formula (B) in about 64% of the first repeating units, and formula (C) in about 20% of the first repeating units.
[0021] Again, referring to the annealed polyimide polymer, the first repeating units may alternately be of a formula (Ib), shown below.
[0022] In formula (Ib), R 1 is a molecular segment having a composition of formula (A), formula (B), or mixtures of formula (A) and formula (B) in the first repeating units where formula (A), and (B) are described above.
[0023] Again, referring to the annealed polyimide polymer, the first repeating units may alternately be of formula (Ia), and/or formula (Ib), wherein formula (Ia) and formula (Ib) are described above.
[0024] In one embodiment of the invention, the annealed polyimide polymer contains a number of second repeating units of formula (II):
wherein the annealed polymer contains less than 3 mol % of the second repeating units.
[0025] In other alternate embodiments, the annealed polyimide polymer contains less than about 1 mole % of the second repeating units, and in one embodiment, the annealed polyimide polymer is substantially void of the second repeating units.
[0026] The polyimide polymer is typically, but not necessarily, a polyimide polymer sold under the tradename P84, P84HT, or mixtures thereof.
[0027] The annealed polyimide polymers of the current invention can be made into any membrane form, and are particularly suited for the production of hollow fiber membranes. Membranes of the annealed polyimide polymer exhibit a surprisingly high maximum strain of above about 50 to 100%.
[0028] A process for producing a fluid separating membrane and the product produced by the process includes the steps of:
(a) providing a polyimide polymer comprising a number of first repeating units of formula (I) as described above; (b) annealing the polyimide polymer to form an annealed polyimide polymer; (c) synthesizing a concentrated solution, wherein the concentrated solution comprises a solvent and the annealed polyimide polymer; and (d) forming a membrane.
[0033] In alternate embodiments of the process above:
(a) the annealing step is conducted by a process of mechanical annealing, thermal annealing, or combinations thereof; (b) the annealing step is conducted for a period of time of about 6-30 hours at a temperature of about 100-250° C.; (c) the annealing step is conducted under a vacuum of greater than about 15 inches of mercury; (d) the annealed polyimide polymer comprises less than about 1 to about 3 mole % of a second repeating unit wherein the second repeating unit is a moiety for formula (II) as described above; and (e) the concentrated solution contains about 30 weight % of the annealed polyimide polymer, wherein the solvent is NMP, and wherein the concentrated solution has a zero-shear complex viscosity of greater than about 90 Pa·s at 40° C.
[0039] Furthermore, this invention includes a method of separating one or more fluids from a fluid mixture comprising the actions of:
(a) providing a fluid separation membrane of the current invention; (b) contacting a fluid mixture with a first side of the fluid separation membrane thereby causing a preferentially permeable fluid of the fluid mixture to permeate the fluid separation membrane faster than a less preferentially permeable fluid to form a permeate fluid mixture enriched in the preferentially permeable fluid on a second side of the fluid separation membrane, and a retentate fluid mixture depleted in the preferentially permeable fluid on the first side of the fluid separation membrane; and (c) withdrawing the permeate fluid mixture and the retentate fluid mixture separately.
BRIEF DESCRIPTION OF DRAWINGS
[0043] For a further understanding of the nature and objects of the present invention, reference should be made to the following detailed description, taken in conjunction with the accompanying drawings, in which like elements are given the same or analogous reference numbers and wherein:
[0044] FIG. 1 shows the conversion of a seven-membered lactone moiety to an imide moiety;
[0045] FIG. 2 shows the chemical reaction that forms a seven-membered lactone moiety;
[0046] FIG. 3 shows the chemical structure of the components of two polyimide polymers;
[0047] FIG. 4 shows NMR results from analysis of virgin polyimide polymers;
[0048] FIG. 5 shows NMR results from analysis of virgin polyimide polymers;
[0049] FIG. 6 shows the dynamic rheology of polyimide polymer samples before annealing;
[0050] FIG. 7 shows the dynamic rheology of polyimide polymer samples after annealing;
[0051] FIG. 8 shows the dynamic rheology of polyimide polymer samples before and after annealing;
[0052] FIG. 9 shows the dynamic rheology of polyimide polymer samples before and after annealing using mechanical and thermal annealing processes; and
[0053] FIG. 10 shows the dynamic rheology of polyimide polymer samples before and after annealing.
DESCRIPTION OF PREFERRED EMBODIMENTS
[0054] The present invention provides a membrane for fluid separation comprising a polyimide polymer that has been subjected to an annealing step (an annealed polyimide polymer), wherein the annealed polyimide polymer contains a number of first repeating units of formula (I) which is described below. Other components can be present in the polymer such as, processing aids, chemical and thermal stabilizers and the like, provided that they do not significantly adversely affect the separation performance of the membrane. Furthermore, the present invention includes a method of producing a polyimide polymer membrane for fluid separation using the annealing process of the current invention, a membrane for fluid separation produced by that method, and a process of using the membrane for fluid separation.
[0055] As used in this application, a “repeating unit” is a molecular segment in the polymer chain backbone that repeats itself regularly along the polymer chain. In this respect, the term repeating units is meant to cover all portions of such polymers and any number of the repeating units.
[0056] As used in this application, an “imidized polymer” or “annealed polyimide polymer”, is a polyimide polymer that has been exposed to the structure-altering thermal or mechanical treatment process of the current invention.
[0057] As used in this application, a “virgin polyimide polymer”, is a polyimide polymer that has not been exposed to the annealing process of the current invention.
[0058] As used in this application, “P84” or “P84HT” refers to polyimide polymers sold under the tradenames P84 and P84HT, respectively from HP Polymers GmbH.
[0059] The membrane of the current invention comprises a polyimide polymer that has been subjected to an annealing step (an annealed polyimide polymer), wherein the annealed polyimide polymer comprises a number of first repeating units of formula (I), which is described below.
[0060] The first repeating units of the annealed polyimide polymer are of a formula (I):
[0061] In formula (I), R 1 is a molecular segment of a formula (A), formula (B), formula (C), or mixtures of formula (A), formula (B), and formula (C), where formula (A), formula (B), and formula (C) are:
[0062] Furthermore, in formula (I), R 2 is a molecular segment of a formula (Q), formula (S), formula (T), or mixtures of formula (Q), formula (S), and formula (T), where formula (Q), formula (S), and formula (T) are:
[0063] In formula (T) above, Z is a molecular segment of a formula (L), formula (M), formula (N), or mixtures of formula (L), formula (M), and/or formula (N), where formula (L), formula (M), and formula (N) are:
[0064] Referring to the annealed polyimide polymer, the first repeating units may alternately be of a formula (Ia), where formula (Ia) is:
[0065] In formula (Ia), R 1 is a molecular segment having a composition of formula (A), formula (B), or formula (C), or a mixture of formula (A), formula (B), or formula (C) in the first repeating units and where formula (A), (B), and (C) are those described above.
[0066] In another alternate embodiment of formula (Ia), the R, in formula (Ia) has a composition of formula (A) in about 10-25% of the first repeating units, formula (B) in about 55-75% of the first repeating units, and formula (C) in about 20-40% of the first repeating units.
[0067] In another alternate embodiment of formula (Ia), the molecular segment R 1 has a composition of formula (A) in about 16% of the first repeating units, formula (B) in about 64% of the first repeating units, and formula (C) in about 20% of the first repeating units.
[0068] Again, referring to the annealed polyimide polymer, the first repeating units may alternately be of a formula (Ib), shown below.
[0069] In formula (Ib), R 1 is a molecular segment having a composition of formula (A), formula (B), or mixtures of formula (A) and formula (B) in the first repeating units where formula (A), and (B) are described above.
[0070] Again, referring to the annealed polyimide polymer, the first repeating units may alternately be of formula (Ia), and/or formula (Ib), wherein formula (Ia) and formula (Ib) are described above.
[0071] In preferred membranes of the current invention, the annealed polyimide polymer makes up about 20-80% of the membrane by weight (wt %). In one preferred embodiment, membranes are produced from an annealed polyimide polymer made from a polyimide polymer belonging to the family of polyimide polymers sold under the tradenames P84, P84HT, or mixtures thereof. The polyimide polymer is annealed in a controlled manner, as described herein below, to form an annealed polyimide polymer, which is then made into the membrane of the current invention. The controlled annealing process allows the polymer to be used to produce a desirable membrane with surprising performance and strength characteristics. Furthermore, the annealing process allows the polyimide polymers to by used to produce membranes in forms that are highly desirable. One preferred membrane form is a hollow fiber. Membranes of the current invention have a maximum strain of above about 50%, preferably above about 100%.
[0072] The annealed polyimide polymers are suitable molecular weight to be film forming and pliable so as to be capable of being formed into continuous films or membranes. The annealed polyimide polymers of this invention preferably, but not necessarily, have an inherent viscosity within the range of about 0.52 to about 0.62 deciliters/gram (dl/gm) and more preferably about 0.54 to about 0.6 dl/gm.
[0073] In one embodiment of the current invention, the annealed polyimide polymer contains less than 3 mole % of a second repeating unit of formula (II):
[0074] In another embodiment, the annealed polyimide polymer comprises less than about 1 mole % second repeating units. In still another embodiment, the annealed polyimide polymer is substantially void of second repeating units.
[0075] The membranes of the current invention are produced by a process comprising the actions of:
a) providing a polyimide polymer comprising a number of first repeating units of formula (I) as described above; b) annealing the polyimide polymer to form an annealed polyimide polymer; c) synthesizing a concentrated solution, wherein the concentrated solution comprises a solvent and the annealed polyimide polymer; and d) forming a membrane.
[0080] In one embodiment of the current invention, the polyimide polymer contains a number of second repeating units of formula (II) as described above. The virgin polyimide polymer of this embodiment typically contains greater than 3 mole % of the second repeating units, and in some embodiments contains from 3 to 10 mole % of the second repeating units. The annealing step of the current invention decreases the number of second repeating units contained in the annealed polyimide polymer to less than about 3 mole %. In other embodiments, the annealing step decreases the number of second repeating units contained in the annealed polyimide polymer to less than about 1 mole %, or removes substantially all of the second repeating units.
[0081] The annealing step can be performed by any annealing process known to one of ordinary skill in the art. Preferable processes for annealing include, but are not limited to mechanical, thermal annealing, or combinations thereof.
[0082] The concentrated solution referenced in the synthesis step of current invention preferably, but not necessarily, contains about 30 weight % (wt %) of the annealed polyimide polymer in NMP solvent. The zero-shear complex viscosity for the concentrated solutions containing NMP and 30 wt % of virgin (non-annealed) polyimide polymers, and NMP and 30 wt % of annealed polyimide polymer are shown in FIGS. 7-11 . The concentrated solution containing the annealed polyimide polymer in one embodiment has a zero-shear complex viscosity of greater than about 90 Pa·s at 40° C., in another of greater than about 150 Pa·s at 40° C., and in yet another of about 150 Pa·s to about 500 Pa·s at 40° C.
[0083] The polyimide polymer of the current invention is preferably, but not necessarily, a polyimide polymer belonging to the family of polyimide polymers sold under the tradenames P84, P84HT, or mixtures of P84 and P84HT. One preferred polyimide polymer has an inherent viscosity of greater than about 0.52 dl/gm before the annealing step. In another embodiment, the annealed polyimide polymer has an inherent viscosity of greater than about 0.58 dl/gm after the annealing step. One preferred process of annealing increases the inherent viscosity of the virgin polyimide polymer by at least about 5%.
[0084] The current invention includes a method of separating one or more fluids from a fluid mixture comprising the actions of:
(a) providing a fluid separation membrane of the current invention; (b) contacting a fluid mixture with a first side of the fluid separation membrane thereby causing a preferentially permeable fluid of the fluid mixture to permeate the fluid separation membrane faster than a less preferentially permeable fluid to form a permeate fluid mixture enriched in the preferentially permeable fluid on a second side of the fluid separation membrane, and a retentate fluid mixture depleted in the preferentially permeable fluid on the first side of the fluid separation membrane; and (c) withdrawing the permeate fluid mixture and the retentate fluid mixture separately.
[0088] The novel method can operate under a wide range of conditions and is thus adapted to accept feed streams supplied from a diverse range of sources. If the feed stream is a fluid that exists already at a sufficiently high pressure and a pressure gradient is maintained across the membrane, the driving force for separation can be adequate without raising feed stream pressure farther. In one preferred embodiment, the driving force for separation is a pressure gradient across the membrane of about 0.60 to about 13.8 MegaPascals (MPa) (100-2000 psi). In another preferred method, the pressure gradient is in a range of about 6.9 to about 13.8 MPa (1000-2000 psi).
[0089] One preferred method feeds a fluid mixture to the fluid separation membrane that comprises carbon dioxide and methane. Another preferred method feeds a fluid mixture to the fluid separation membrane that comprises carbon dioxide and methane, and the pressure gradient across the membrane is in a range of about 6.9 to about 13.8 MPa (1000-2000 psi).
[0090] The annealing step of the current invention is a controlled anneal. The current method controls the temperature and time of the annealing step to achieve the desired results on the polymer structure. One method of annealing places commercially available virgin polyimide polymer in an oven or rotary dryer for a specified period of time where the temperature and atmospheric conditions are controlled. The temperature in the oven or rotary dryer is preferably about 100-250° C., more preferably about 140-180° C. The oven or rotary dryer is preferably, but not necessarily, placed under a vacuum of greater than 15 inches of mercury, more preferably greater than 20 inches of mercury, and even more preferably about 20 to 25 inches of mercury. The polyimide polymer is held at the above conditions for about 6-30 hours, and more preferably about 10-16 hours. Furthermore, this method optionally may include a nitrogen sweep of the oven or rotary drier to remove gases evolving from the polyimide polymer. Preferred polyimide polymers include, but are not limited to, polyimide polymers sold under the tradename P84 or P84HT.
[0091] Controlled annealing of these polyimide polymers is beneficial in increasing the molecular weight (MW) and degree of imidization. In one embodiment, controlling the annealing step at about 160° C. for 12 hours in a convection oven and commercially utilized rotary dryers under high levels of vacuum (20 to 25 inches of mercury) with nitrogen sweep gas results in an increase in MW and degree of imidization of the polymer while retaining the ability of the polymer to dissolve in several aprotic solvents that can be utilized in fiber spinning. Excessive annealing at higher temperatures and longer times impairs dissolution due to enhanced long chain branching and crosslinking reactions; therefore, excessive annealing is not desirable.
[0092] Concentrated spin dope solutions synthesized with the annealed polyimide polymer exhibit an increase in zero-shear viscosity over solutions synthesized with the virgin polyimide polymer. The increase in zero-shear viscosity enhances spinnability of the annealed polymer, thus allowing hollow fiber membranes to be easily produced from annealed poyimide polymers. Furthermore, fibers spun from spin dope formulations prepared from polyimide polymer subjected to a controlled anneal exhibit surprisingly enhanced mechanical properties, particularly maximum strain, necessary for gas separation module forming operations as well as capability for stable operation at high temperature and pressure in gas separation applications. These hollow fiber membranes offer significant economic advantages due to their good separation performance, surprising mechanical properties, and unusual hydrocarbon resistance in several industrial applications involving refinery H 2 separations and natural gas sweetening.
[0093] Membranes of polyimide polymers are desirable for their chemical resistant properties. However, some commercially available polyimide polymers are low molecular weight (MW) and prone to hydrolysis. In particular, the polyimide polymers sold under the tradename P84, which are synthesized by condensation polymerization of diisocyanates with dianhydrides, are believed to be prone to hydrolysis. Although not intended to be bound by a theoretical understanding of the hydrolysis, it is thought that these polymers contain greater than about 3 mole % of a thermally liable and hydrolytically unstable intermediate that is a seven-membered lactone moiety. Solution spinning of these polymers results in extremely brittle hollow fibers due to MW breakdown by hydrolysis. Due to the poor mechanical properties of these fibers, the polyimide polymers are not commercially favourable for producing gas separation membranes, particularly hollow fiber membranes.
[0094] Although not intended to be bound by a theoretical understanding of the mechanism of annealing, it is thought that the virgin polyimide polymer of formula (I) also contains a second repeating unit, which is a seven-membered lactone moiety that causes the virgin polyimide polymer to be prone to hydrolysis and makes it difficult to commercially produce asymmetric membranes from the polymer. It is particularly difficult to produce hollow fiber membranes. In particular, the polyimide polymers sold under the tradename P84, which are synthesized by condensation polymerization of diisocyanates with dianhydrides, are believed to contain the unstable intermediate moiety that is subject to hydrolysis. Nuclear Magnetic Resonance (NMR) analysis supports the theory of the presence of the unstable intermediate. Thermogravimetric analysis coupled with IR (TGA/IR) and NMR data indicate that the seven-membered lactone moiety, of formula (II) described above, found in the virgin polyimide polymer is substantially converted in the annealing process to a stable moiety accompanied by the evolution of CO 2 gas. Referring to FIG. 6 , TGA/IR data confirms that CO 2 evolution starts around 145 to 155° C. and the rate of evolution starts to significantly increase around 180° C. Thus, in a controlled anneal, one would preferably control the temperature to be above about 145° C. and below about 180° C.
[0095] FIG. 3 depicts the general structures of one embodiment using polyimide polymers sold under the tradename P84. Referring to FIG. 2 , and not intending to be bound by a theoretical understanding of the mechanism of annealing, it is thought that the second repeating units, the thermally liable seven-membered ring intermediates of formula (II), are generated as a result of the reaction of the diisoyanate with a dianhydride. Referring to FIG. 1 , upon controlled annealing, the second repeating units are converted to stable imide moieties, accompanied by CO 2 evolution. The C13 NMR for the aromatic portion of the spectrum in NMP solution for the polyimide polymer is shown in FIG. 4 . Polymer samples were dissolved in NMP at 5 wt %, and solutions were run at 30° C. on a Varian Inova 500 MHz NMR spectrometer. Spectra for all the samples were collected under the same conditions.
[0096] Signals from the BTDA carbonyl and imide carbonyls are also marked in FIG. 4 . Spectra from the other samples analyzed were similar. Ratios of the intensity of the imide carbonyls to signal attributed to TDI were found to be similar indicating that the large and small batches of the polyimide polymer were of approximately the same stoichiometry. FIG. 5 contains an expansion of the imide carbonyl region. In addition to the imide carbonyls, two other weak signals are observed. A down-field peak is located at 166.75 ppm and an up-field peak is located at 161.80 ppm. These peaks are generally attributed to either the acid and amide carbonyls formed when the anhydride opens to form the amic acid or the two carboxylic acid carbons of a BTDA end group. However, the carbonyls of the second repeating units can also be attributed to these weak carbonyl signals. Integration data for the up-field and down-field peaks is given in Table 1. The total area was kept constant and the relative percentages in moles of the up-field and down-field peaks as well as the imide carbonyls are shown. We observe in Table 1 that both sets of samples contain the up-field and down-field carbonyl peaks at approximately 1 mole % level, which are reduced upon annealing. We also see that the degree of imidization is increased due to annealing, indicating conversion of the second repeating units (the thermally liable seven-membered ring intermediate) to a stable imide moiety. The loss of these weak carbonyl peaks could also be due to further polymerization.
TABLE 1 Sample number Downfield % Imide % Upfield % E102973-11-1 1.12 97.92 0.97 E102973-11-2 1.07 98.15 0.77 E102973-11-3 1.28 97.49 1.23 E102973-11-4 0.42 99.60 — 11-1 is a small batch of non-annealed polyimide polymers 11-2 is batch 11-1 annealed at 150° C. for 24 hours in a convection oven 11-3 is a large batch of non-annealed polyimide polymers 11-4 is 11-3 annealed at 150° C. for 24 hours in a convection oven
[0097] The evolution of CO 2 supports the theory that the second repeating units are converted to a stable moiety during annealing. TGA (Thermogravimetric analysis)/IR data clearly indicates CO 2 evolution during annealing. The chemigram for CO 2 evolution shows the integrated absorbance (infrared signal) of a specified spectral region as a function of time is included in FIG. 6 , which indicates that CO 2 evolution starts somewhere in a range of about 145 to 155° C. FIG. 6 is marked as definitely evidencing CO 2 evolution by about 155° C., but one can see that the evolution may start as low as about 145° C. Table 2 summarizes the quantitative TGA/IR results. The total weight loss from the typical polyimide polymer flake over the 25 to 400° C. range is about 3.40 wt %. About 0.7 wt % is due to CO 2 evolution. Thus, the TGA/IR data supports the NMR conclusion above that the intensity of the weak carbonyl peaks is reduced by annealing, presumably due to conversion of the second repeating units to a stable moiety accompanied by CO 2 evolution.
TABLE 2 Evolved Gas H 2 0 C0 2 CO DMF Quantity, weight % 0.70 0.012 0.02 Temperature, ° C. 25-50 x x 150-200 x x 200-250 x x 250-300 x x 300-350 x 350-400 x x
[0098] Furthermore, the polymer molecular weight is increased by the annealing step, which is consistent with the conclusions reached based on the NMR data. Table 3 summarizes the inherent viscosities, intrinsic viscosities, and weight average molecular weights (MW) as measured by size exclusion chromatography (SEC) for three different lots of polyimide polymer that were annealed at different temperatures and times of annealing. These annealing experiments were conducted in a convection oven and in a rotary dryer wherein the polymer samples were exposed to a vacuum level of 18 to 25 inches of Hg with a N 2 sweep gas. Clearly, annealing the polymer increased the molecular weight, which is consistent with the conclusion that the second repeating units are converted to stable moieties.
TABLE 3 Inherent Intrinsic Annealing Viscosity, Viscosity, SEC Lot Conditions dl/gm dl/gm MW 811 — 0.52 — — Virgin 811 175° C./12 hrs 0.6 — — Annealed in convection oven 8015 — 0.56 0.39 26.5K Virgin 8015 160° C./12 hrs 0.59 0.437 30.3K Annealed in rotary drier 5002 — 0.55 0.38 24.1K Virgin 5002 175° C./20 hrs 0.58 0.433 30.6K Annealed in rotary drier SEC MW - weight average molecular weight measured by SEC in solvent dimethylacetamide
[0099] One preferred polyimide polymer described herein is a polyimide polymer sold under the trade name P84, or P84-HT. Alternately, polyimide polymers may be made by methods well known in the art. The polyimide polymers can, for example, be conveniently made by polycondensation of an appropriate diisocyanate with approximately an equimolar amount of an appropriate dianhydride. Alternatively, the polyimide polymers can be, for example, made by polycondensation of equimolar amounts of a dianhydride and a diamine to form a polyamic acid followed by chemical or thermal dehydration to form the polyimide. The diisocyanates, diamines, and dianhydrides useful for making the polyimides of interest are usually available commercially.
[0100] Preferred polyimide polymers are soluble in a wide range of common organic solvents including most amide solvents that are typically used for the formation of polymeric membranes, such as N-methyl pyrrolidone (“NMP”), N,N-dimethyl acetamide (“DMAC”), or highly polar solvents such as m-cresol.
[0101] The membranes of the current invention can be fabricated into a wide variety of membrane forms by appropriate conventional methods known to one of ordinary skill in the art. The annealed polyimide polymers may be used to form a single-layer membrane of an unsupported film or fiber. The separation membrane may also comprise a very thin selective layer that forms part of a thicker structure. This may be, for example, an integral asymmetric membrane, comprising a dense skin region that forms the selective layer and a micro-porous support region. Such membranes are described, for example, in U.S. Pat. No. 5,015,270. As a further alternative, the membrane may be a composite membrane, that is, a membrane having multiple layers. Composite membranes typically comprise a porous but non-selective support membrane, which provides mechanical strength, coated with a thin selective layer of another material that is primarily responsible for the separation properties. Typically, such a composite membrane is made by solution-casting (or spinning in the case of hollow fibers) the support membrane, then, solution-coating the selective layer in a separate step. Alternatively, hollow-fiber composite membranes can be made by co-extrusion spinning of both the support material and the separating layer simultaneously as described in U. S. Pat. No. 5,085,676.
[0102] For non-limiting illustrative purposes, one method to prepare membranes in accordance with this invention is generally described as follows. An annealed polyimide polymer in dry particulate form is dissolved in a suitable solvent, such as N-methylpyrrolidone, at a suitable polymer content, such as approximately 20-35% by weight (wt %). The polymer solution is cast as a sheet at the desired thickness onto a flat support layer (for flat sheet membranes), or extruded through a conventional hollow fiber spinneret (for hollow fiber membranes). If a uniformly dense membrane is desired, the solvent is slowly removed by heating or other means of evaporation. If an asymmetric membrane is desired, the film or fiber structure is quenched in a liquid that is a non-solvent for the polymer and that is miscible with the solvent for the polyimide. Alternatively, if a composite membrane is desired, the polymer is cast or extruded over a porous support of another material in either flat film or hollow fiber form. The separating layer of the composite membrane can be a dense, ultra-thin, or asymmetric film.
[0103] The resulting membranes may be mounted in any convenient type of housing or vessel adapted to provide a supply of the feed fluid, and removal of the permeate and residue fluids. The vessel also provides a high-pressure side or first side (for the feed fluid and residue fluid) and a low-pressure or second side of the membrane (for the permeate fluid). For example, flat-sheet membranes can be stacked in plate-and-frame modules or wound in spiral-wound modules. Hollow-fiber membranes are typically potted with a thermoset resin in cylindrical housings. The final membrane separation unit comprises one or more membrane modules, which may be housed individually in pressure vessels or multiple elements may be mounted together in a sealed housing of appropriate diameter and length.
[0104] The membranes of the current invention exhibit an excellent combination of high permselectivity and permeability for the separation of gases. Furthermore, the membranes exhibit surprisingly superior mechanical properties, which, enables the membranes to be easily fabricated into desired membrane forms that can withstand high membrane differential pressures and high temperatures.
[0105] The membranes of this invention are suitable for operating under the high pressures required for industrial separations. For example, membranes must be capable of withstanding a transmembrane pressure of 10-13.8 MPa (1500-2000 psi) in many petrochemical operations, and up to 10 MPa in natural gas sweetening operations. Typical hollow-fiber membranes are susceptible to collapse under these conditions unless the walls of the hollow fiber are capable of withstanding the forces of high pressure. Annealing the polyimides of this invention surprisingly increases the mechanical properties of the membranes, making it possible to produce hollow fiber membranes of the annealed polyimide polymers that are suitable for higher trans-membrane pressure applications.
[0106] Membranes of the current invention enable an attractive combination of carbon dioxide permeability and permselectivity for carbon dioxide over methane, nitrogen, and the like. The membranes exhibit surprising mechanical strength and exhibit little or no plasticization by carbon dioxide or aliphatic hydrocarbons, and are thus especially useful for the removal of carbon dioxide from industrially significant fluid streams, such as in natural gas sweetening. Even at high operating pressure, membranes of the current invention possess an excellent balance of fluid permeation rates and selectivity of one fluid over other fluids in the multi-component fluid mixture.
EXAMPLES
[0107] This invention is now illustrated by examples of certain representative, non-limiting embodiments thereof.
[0108] Hollow fiber membranes were produced from virgin (non-annealed) polyimide polymers and annealed polyimide polymers of the current invention. The fibers were tested for separation performance and mechanical properties, and compared. The results, summarized in Table 4, clearly indicate the superior permeation performance and surprising mechanical characteristics of the membranes produced from the annealed polyimide polymer.
TABLE 4 Comparative Example of the Example Invention (Non-Annealed) (Annealed) He Permeance 200 280 (untreated) He/N 2 Selectivity 25 62 (untreated) He Permeance 119 213 (treated) He/N 2 Selectivity 167 200 (treated) Elastic Modulus 896 703 (MPa) Yield Stress 30 29 (MPa) Maximum Strain 5-15 119 (%) Permeance is reported in GPU (Gas Permeation Unit) 1 GPU = 1 × 10 −6 cm 3 (STP)/(cm 2 s cmHg) MPa = MegaPascals
[0109] A Comparative example of non-annealed polyimide polymer membrane was produced for testing. A concentrated solution (spin dope) containing 33% by weight polyimide polymer sold under the tradename P84 (lot 811 with an inherent viscosity of 0.52 dl/gm), 4.95% CaBr 2 , and 1.65% acetic anhydride in N-methyl 2 pyrolidone (NMP) was prepared.
[0110] The concentrated solution was extruded at a rate of 180 cm 3 /hr through a spinneret with fiber channel dimensions of outer diameter 559 microns and inner diameter equal to 254 microns at 90° C. A solution containing 87% weight NMP in water was injected to the bore of the fiber at a rate of 33 cm 3 /hr. The nascent fiber traveled through an air gap length of 1 cm at room temperature into a water coagulant bath at 5° C. and wound up at a rate of 55 meters/min. The water-wet fiber was rinsed with running water at 50° C. for about 12 hours and then sequentially exchanged with methanol and hexane as taught in U.S. Pat. Nos. 4,080,744 and 4,120,098, followed by drying at 100° C. in a vacuum oven for one hour.
[0111] Fibers of the Comparative example were tested for He/N 2 separation while applying 69 MPa (100 psi) pressure in the shell side of the fibers at 23° C. The results are reported in Table 4.
[0112] The Comparative example fibers were treated to seal defects in the dense separating layer by contacting the outer surfaces of the fibers with a 2% weight solution of Sylgard 184 (Dow Corning Corp) in iso-octane. The exposure time of the fibers to the post-treatment was 30 minutes. The fibers were dried in a vacuum oven at 100° C. The treated fibers were tested as above and the results are reported in Table 4.
[0113] The Comparative example fibers produced from the virgin polyimide polymer were brittle during handling and exhibited filament-to-filament variability in elongation at break. Several fibers fell apart during handling, which made module preparation process very difficult. The inherent viscosity of the polymer fibers was measured and found to be about 0.34 dl/gm, which indicated a significant reduction in polymer molecular weight. This reduction in weight, as discussed above is due to base catalyzed hydrolysis of the imide linkages in the spin dope preparation and storage and spinning steps at elevated temperatures and subsequent fiber washing and dehydration steps. The mechanical properties of the fibers were measured in extension and the results are reported in Table 4. The low and variable maximum strain is consistent with the observation that the fibers were brittle, presumably as a result of polymer molecular weight degradation.
[0114] An example of an annealed polyimide polymer membrane was also produced. A sample of polyimide polymer sold under the tradename P84 (lot 811, which is the same lot as the Comparative example above), was annealed in a convection oven at 175° C. for 20 hours while being exposed to a vacuum level of about 20 inches of Hg with a N 2 sweep. The inherent viscosity of the annealed polymer sample was measured to be 0.6 dl/gm, which indicates a significant increase in polymer molecular weight over the non-annealed sample. The annealed polymer was utilized to prepare a concentrated solution (spin dope) containing 32% by weight annealed polyimide polymer, 1.6% CaBr 2 , 1.6% acetic anhydride, 0.32% acetic acid, and 6.4% tetramethylenesulfone in NMP. The concentrated solution was extruded at a rate of 180 cm 3 /hr through a spinneret with fiber channel dimensions of outer diameter 559 microns and inner diameter equal to 254 microns at 80° C. A solution containing 85% weight NMP in water was injected to the bore of the fiber at a rate of 33 cm 3 /hr. The nascent fiber traveled through an air gap length of 2.5 cm at room temperature into a water coagulant bath at 25° C. and wound up at a rate of 55 meters/min. The water-wet fiber was washed and dehydrated as discussed in the Comparative example above.
[0115] The example fibers were tested for He/N 2 separation while applying 0.69 MPa (100 psi) pressure in the shell side of the fibers at 23° C. The results are reported in Table 4.
[0116] The example fibers were treated as described for the Comparative example above and tested to obtain the results reported in Table 4.
[0117] The inherent viscosity of the example fibers was measured and found to be about 0.6 dl/gm indicating essentially no polymer molecular weight degradation for the annealed polymer. The mechanical properties of the fibers were also measured to obtain the results reported in Table 4. The maximum strain surprisingly exhibited essentially no filament-to-filament variability. The fibers spun from the annealed polyimide polymer could be readily subjected to downstream processing operations without breaking because of increased elasticity.
[0118] Although the present invention has been described in considerable detail with reference to certain preferred versions and examples thereof, other versions are possible. Therefore, the spirit and scope of the appended claims should not be limited to the description of the preferred versions contained herein.
[0119] All the features disclosed in this specification (including any accompanying claims, abstract, and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.
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This abstract discusses membranes needed to separate fluids for the production of oxygen-enriched air, nitrogen-enriched-air, for the separation of carbon dioxide from hydrocarbons, and the separation of hydrogen from various petrochemical and oil refining streams. Membranes are needed that provide a resistance to interaction with process components or contaminants, provide the mechanical strength required to withstand high membrane differential pressures and high process temperatures, and exhibit sufficient maximum strain such that membranes are not brittle and can easily be formed into desirable membrane forms. Membranes of polyimide polymers, particularly polyimide polymers sold under the trade name P-84, are annealed in a controlled annealing step to improve the mechanical properties of the polymers used to make separation membranes. The resulting annealed polyimide polymer is used to produce various forms of high strength, chemically resistant membranes, including hollow-fiber membranes that are suitable for high pressure, high temperature applications.
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BACKGROUND OF THE INVENTION
The present invention relates generally to fuze circuits and more particularly to firing circuits for fuzes.
Safety considerations in the design of fuze circuits has already been of prime importance. False firings of projectiles and bombs due to improperly designed fuzes can cause extensive damage to property and life. Safety precautions, such as grounding the electronic circuit of the fuze to the weapon's casing and driving the fuze circuit with a negative supply, have virtually eliminated false firings due to the outside electromagnetic energy interference. However, such precautions have resulted in the necessity of entirely new fuze circuitry operable from a negative supply. For example, standard capacitive discharge circuitry is inoperable from a negative supply when the load is grounded.
In addition, due to the limited space available in the weapon, fuze design has required a minimum number of components to carry out designed functions necessary to the operation of the fuze. For example, standard fullwave rectifiers and integrators contain too many electrical components and are too bulky for fuze design.
SUMMARY OF THE INVENTION
The present invention overcomes the disadvantages and limitations of the prior art by providing an improved integrator and firing circuit for fuzes.
The present invention utilizes a transistor as a unity gain inverter for negative doppler signal excursions from the detector portion of the fuze and is switched to saturation mode for positive excursions. The waveform at the collector thus closely approximate a fullwave rectification of the input doppler signal from the detector of the fuze. This eliminates the use of a standard, bulky diode bridge for a single transistor. A programmable unijunction transistor (PUT) is used in conjunction with voltage dividing resistors to cause a pulse when the threshold level is exceeded to fire a silicon controlled rectifier (SCR). The SCR is connected to a novel capacitive discharge circuit used to fire the squib.
It is therefore the object of the present invention to provide an improved firing circuit for a fuze.
It is also an object of the present invention to provide a firing circuit which is inexpensive and expendable.
Another object of the present invention is to provide a firing circuit which is small and compact.
Other objects, advantages and novel features of the invention will become apparent from the following detailed description of the invention when considered in conjuction with the accompanying drawings wherein:
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of the entire fuze circuit.
FIG. 2 is a diagram of the integrator and firing circuit comprising the preferred embodiment of the present invention.
FIG. 3A to 3F disclose waveforms at particular locations in the circuit of FIG. 2.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 discloses the overall fuze circuit in block diagram form. The fuze detector 10 detects a signal indicating a target. The amplifier 12 and automatic gain control 14 amplify and filter the signal presented to the integrator firing circuit 16 so that it presents a sinusoidally shaped signal as shown in FIG. 3A of the detected doppler wave sensed by RF detector 10. The integrator firing circuit 16, comprising the present invention, produces a firing pulse to fire the squib 18 when its input sinusoidal signal exceeds a threshold level indicating the presence of a target.
FIG. 2 discloses the circuitry comprising the preferred embodiment of the present invention disclosed in FIG. 1 as element 16. The waveform of FIG. 3A is applied to the base of transistor 20. The emitter lead follows that waveform as shown in FIG. 3B. However the output at the collector of transistor 20 closely approximates a fullwave rectification from the doppler output of amplifier 12 as shown in FIG. 3C. Transistor 20 thus behaves as a unity gain inverter to negative input signal excursions and is switched to a saturation mode for positive input signal excursions.
Resistor 26 and capacitor 28 act as an inverter of the full wave rectifier signal shown in FIG. 3C. This rectified signal causes a more positive charge to build up on integrating capacitor 28 as shown in FIG. 3D which is biased at -10 volts until the input to the anode of the programmable unijunction transistor (PUT) 30 exceeds the voltage input at the gate of the PUT 30 at which time the PUT is switched "on" causing a pulse to be applied to the gate of SCR 38 as shown in FIG. 3E. Resistors 34 and 36 set the threshold level of the gate of PUT 30.
The SCR 38 is used to discharge the firing capacitor 42 of the capacitive discharge firing circuit constituting elements 40, 42, and 44. Resistors 40 and 44 act as charging resistors for firing capacitor 42. The pulse applied to the gate of SCR 38 causes it to conduct and form a path to ground potential to discharge the firing capacitor 42 rapidly thereby forming a pulse which fires the squib 46.
For safety purposes the squib is grounded. This novel configuration of the capacitive discharge circuit which was developed for this system is therefore necessary since the SCR 38 could only be connected through the negative supply voltage via the high impedance charging resistor 40. No other configuration of the firing circuit allows operation with a negative supply voltage and a squib with one terminal grounded to insure safety.
Obviously many modifications variations of the present invention are possible in light of above teachings. It is therefore to be understood that wi the scope of the appended claims the invention may be practiced otherwise than as specifically described.
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A projectile proximity fuze firing circuit which is compatible with the rirements of both a negative supply voltage and a grounded electronic detonator. In addition, a simple and novel transistor full wave rectifier and integrator is disclosed.
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BACKGROUND OF THE INVENTION
The present invention relates to improvements in processing baled waste material containing waste paper articles of various types for recycling the contents of the bale to recover a maximum amount of cellulosic fibers from the various categories and types of paper fiber containing articles that are contained in the bale of waste material with a minimum degradation or damage to the recovered paper fibers.
To enhance the conservation of material resources, particularly forest land, and to reduce the amount of waste material that is disposed in ever increasing landfill areas, widespread interest has developed in recycling waste matter of which a significant portion comprises waste paper articles of assorted types and compositions for recovering the fibers of the waste paper articles that are used in producing recycled paper products. Waste matter of various categories normally is packaged as tightly compacted bales of considerable size and weight for ease of handling and storage. The nature of these tightly compacted and very heavy bales presents serious problems in processing the miscellaneous tightly compacted contents of the bale in an economical and efficient manner such that the fibers recovered from the miscellaneous types of waste paper articles in the bale are of a high quality and free of contaminants with minimal damage to the fibers from being cut, broken or shortened in the recycling defibration operations. Our U.S. Pat. Nos. 5,147,502 and 5,203,966 discuss this problem at considerable length and disclose measures by which the contents of the tightly compacted bales of waste material can be subjected to a pre-recycling conditioning treatment which causes the fibers of waste paper articles contained in the tightly compacted bale to become swollen and the fiber bonding forces substantially weakened prior to defibration of the waste paper articles and separation of the fibers into a liquid suspension slurry. As discussed in our aforesaid patents, this pre-recycling conditioning treatment involves a thorough wetting impregnation of the contents of the compacted baled waste material by discharging a high velocity jet of cellulosic fiber softening and swelling fluid into the interior of the bale as saturates the waste material in the bales with the fluid to a degree as establishes the desired debonding swelling of the fibers of the waste paper articles in the baled waste material. This debonding swelling reduces the bonds between the fibers of the waste paper articles and between the waste paper fibers and contaminants that form a portion of the waste paper articles. Other previously known measures by which the contents of compacted baled waste material can be subjected to pre-recycling conditioning treatment comprise the submergence of the baled waste material in a water-filled trough for a protracted period prior to breaking up the bale and defibrating the water saturated waste paper as in the manner disclosed in U.S. Pat. No. 4,458,845 of Marcalus, et al. However, this old procedure has the serious disadvantage of requiring an excessive time period for the waste paper contents of a tightly compacted bale to become sufficiently saturated with the debonding fluid. Entrapped air within a bale submerged in a water filled trough prevents a high degree of saturation of the waste paper in the bale within a reasonable period of time.
Waste paper contained in baled waste material normally includes a wide variety of types of cellulosic fiber containing articles of which the fibers of some articles are substantially free of contaminants such as wax, plastics, latex, asphalt or other non-fibrous matter. Relatively uncontaminated fiber articles of this nature are broke, post-consumer paper products such as corrugated boxes, discarded office papers, stationery, toweling, etc. The fibers comprising other types of paper articles contain contaminated matter in which the fibers and their outer walls have been penetrated to various degrees by and contain non-fibrous contaminants in which the contaminants provide special qualities to the fibers of the article such as wet strength. Other types of paper articles have fluid barrier coated surfaces in which the contaminant coating establishes a barrier to the penetration of fluids into the interior fibrous portion of the article. Typical of this latter type of article, and which presents serious problems in penetration of a debonding fluid into the barrier coated fibrous matter, are milk cartons, aseptic juice boxes, freezer wrap, foil laminated cartons, coated sanitary products, moisture barrier shipping sacks, etc. After the defibration separation out of the relatively uncontaminated cellulosic fibers of waste paper contained in bales subjected to the pre-recycling conditioning treatment procedures disclosed in the above mentioned patents, it has been the general practice to dispose the non-debonded and contaminant containing or contaminant coated fibrous matter to landfill along with the non-fibrous waste matter and contaminants contained in the bales due to the difficulty of a further separation out of the cellulosic fibers of waste paper articles containing a high degree of contaminated fibrous matter or whose surfaces are coated with a fluid barrier contaminant.
SUMMARY OF THE INVENTION
The object of this invention is to establish a recovery of the maximum amount of high quality cellulosic fibers from all types of fiber containing waste paper articles that are to be found in compactly baled waste material, including such waste paper articles as those having one or more fluid barrier coatings. In furthering the above indicated objective, a series of three experiments were performed in determining the degree of penetration and penetration time for a liquid to penetrate through the exposed edges into the interior of a polymer coated paperboard sandwich (i.e., milk carton samples) by subjecting the samples to one or more liquid impregnation cycles comprising immersion of the sample in a liquid under varying degrees of vacuum pressure environment followed by the reapplication of atmospheric pressure, which is referred to in subsequent discussions as over pressure and can be greater than ambient atmospheric pressure under certain conditions subsequently discussed. The experiments were conducted on polymer coated milk carton samples of which the outer edges had been severed for exposure of the outer edges to liquid penetration into the fibrous interior of the sandwich sample.
TEST RESULTS
Circular discs 14.2 centimeters (cm) in diameter were subjected to three different conditions and the depth of penetration measured after 60 seconds and 180 seconds:
A. A circular disc was subjected to a vacuum of 25" Hg below atmospheric pressure, water was introduced after 3 minutes of evacuation and atmospheric pressure restored after which penetration was observed. This procedure was repeated twice more while the partially penetrated disc was submerged in the water.
B. A circular disc was subjected to a vacuum of 29.4" Hg below atmospheric pressure, water was introduced after 3 minutes of evacuation and atmospheric pressure restored after which penetration was observed. This procedure was repeated while the partially penetrated disc was submerged in the water.
C. A circular disc was subjected to a vacuum of 29.4" Hg below atmospheric pressure, water was introduced after 3 minutes of evacuation and atmospheric pressure restored after which penetration was observed. This procedure was repeated after first draining the water introduced in the first evacuation.
______________________________________ Penetration Depth (%) After AfterTrialVacuum Stage Condition 60" 180"______________________________________A 25" HG 1st Evac. Not submerged 37 5825" 2nd Submerged 66 7225" 3rd Submerged 74 76B 29.4" Hg 1st Evac. Not submerged 54 7329.0" Hg 2nd Submerged 92 96C 29.4" Hg 1st Evac. Not submerged 49 7529.0" Hg 2nd Not submerged 96 99______________________________________
In Trials "A" and "B" the 2nd evacuation without removal of water, fine air bubbles were observed emanating from the edges of the discs.
The conclusions from these trials were:
1. One stage of treatment at a vacuum of 29.4" Hg is equivalent to 3 stages at 25" Hg in penetration depth.
2. Removal of the water before the 2nd evacuation appeared to be somewhat beneficial, but to a minor degree.
3. Air is trapped in the interior of the paper-polymer sandwich after the first stage of penetration, which inhibits further penetration, and further evacuation of the air is required to obtain more complete penetration of the fluid.
4. Since air is trapped by the impervious polymer barriers, an over pressure of atmospheric or greater would be an aid increasing the depth of fluid penetration. For instance, the depth of penetration after a 29.4" Hg vacuum followed by one atmosphere (14.7 psi) over pressure would be 75% after 180 seconds; and 99%+ after the 2nd evacuation @ 29.0" Hg followed by one atmosphere over pressure. At the lower vacuum of 25" Hg, one atmosphere of over pressure would increase the penetration from 58% after the 1st evacuation to 72% after the second evacuation, and to only 76% after the 3rd evacuation.
5. From these trial results the combination of 29" Hg or more of vacuum, followed by over pressure, and/or removing the fluid after each stage of treatment, will permit effective penetration treatment of polymer sandwiched paper-board. The effects quantified in the above trials have been observed in the depth of penetration of densely packed bales of waste containing paper; bale densities of 20 to 35 pounds per cubic foot.
6. A modelling of these test results to determine the effectiveness of the application above atmospheric pressure after the evacuation shows that the calculated depth of penetration of trial "B", if conducted at a 500 psig over pressure instead of 14.7 psia, the expected depth of penetration would be increased from 73% to 95% after a 34 second penetration time.
7. A further significant finding derived from observation of the tests is that the polymer outer coating of the samples became separated from the fibrous material comprising the central portion of the sandwich and remained as an integral unit of contaminant matter having little or no reduction in size from its original outer covering dimensions. As such, the relatively large segments of integral contaminant matter separated from the fibrous center of the sandwich are more easily separable from the cellulosic fibers of the center portion of the sandwich in the recycling defibration of the cellulose matter.
From these experiments and computer modelling based thereon, we have discovered the effects which the degree of vacuum pressure and subsequent over pressure environment and the number of sequential applications of vacuum and over pressure environments have on the degree to which liquid penetrates into the interior of a polymer coated paperboard sandwich under the imposed pressure environments. Through computer modelling of the above indicated experimental data, certain conclusions can be derived relative to the pressure environment which would be optimum for penetration into paper fiber containing articles which contain significant amounts of contaminants or whose surfaces have a fluid barrier coating of a contaminant. The test results were modelled in applying the results to strips of polycoated paperboard sandwiches as well as to discs and also to the application of over pressures (subsequent to liquid submergence under vacuum) that are greater than atmospheric pressure to include a number of combinations of applications of vacuum and over pressure.
All of the modelling results apply to treatments of bales containing polycoated paperboard which remain submerged throughout the second and subsequent cycles and to that polycoated paperboard which is located in the bottom of a submerged bale. Therefore, the amount of vacuum applied in the modelling in the 2nd and subsequent cycles is corrected for immersion in three feet of water.
The penetration times are first estimated for discs which are 14.2 centimeters in diameter and for strips which are 14.2 centimeters wide. Times for other diameters and widths are estimated by multiplying them by the square of the ratio of their diameters or widths as the case may be. The results are illustrated for one inch discs and strips.
In the Table below, the column titled Initial & Cycle Time includes estimates of the times required for 1 inch discs and strips:
to open and close the treatment vessel door, load and unload a bale, establish the initial vacuum, add the fluid, repressurize and withdraw the treatment fluid--a one-time total of six minutes;
and, in the 2nd and subsequent cycles, to reestablish vacuum and maintain it for an additional three minute dwell time which was observed to be required to complete the period of bubbling from the polycoated board which was observed in the experiments--a total of 5 minutes for each cycle of treatment after the first.
Total bale treatment time is Initial plus Cycle Time (includes Penetration Time).
The following Table indicates the extended results derived from modelling the above indicated Test Results:
__________________________________________________________________________EXTENDED RESULTS FROM MODELLINGBoard Initial plusgeometry Number Vacuum Over Pressure Penetration time Cycle Time& depth of in pressure Ratio in min. & sec. in mins forpenetration cycles Hg · g in psig 1st/2nd+ 14.2 cm 1.0 in. 1" discs & strip__________________________________________________________________________Disc/95% 1 -28.9 500 1051 34" 1" 6'Disc/95% 2 -28.9 53 137/38 7'11" 14" 11'Disc/95 3 -28.8 0 28/8.0 39'20" 1'16" 16'Disc/95% 4 -26.5 0 8.8/4.9 42'20" 1'21" 21'Disc/95% 5 -23.9 0 4.9/3.4 43' 1'23" 26'Strip/98% 1 -28.9 500 1051 13" 1" 6'Strip/98% 2 -28.9 203 444/121 38" 1" 11'Strip/98% 3 -28.9 24 80/20 3'19" 6" 16'Strip/98% 4 -28.1 0 17/6.8 8'20" 16" 21'Strip/98% 5 -25.9 0 7.4/4.5 7'50" 15" 26'Strip/98% 6 -23.7 0 4.8/3.4 7'22" 14" 31'__________________________________________________________________________
CONCLUSIONS
Penetration times for 1 inch discs and stripes are not significant. Therefore, for design purposes total treatment time is the initial plus cycle times which becomes excessive as the number of cycles exceeds six. The preferred treatment is a one-cycle process with an over pressure of 500 psig and a vacuum of -29 inches Hg. gage, both of which are easily incorporated into equipment for an operating bale treatment process.
The three experiments and the resultant modelling indicate that an effective pre-recycling conditioning penetration of liquid into a bale containing paper and paperboard articles of a nature that exposure of the fibers of the articles to fluid wetting are restricted can be expected within a reasonable bale treatment time under the following parameters:
(1) introducing fluid into the bale in which the bale is subjected to consecutive cyclic environments of a vacuum pressure of at least 25" of mercury below atmospheric pressure (-25" Hg gage) followed by an over pressure of at least one atmosphere.
(2) When the applied vacuum pressure is less than -25" Hg gage, an over pressure greater than one atmosphere is required.
(3) A ratio of the absolute pressures of the over pressure and vacuum pressure of six is required for an effective cycle.
(4) When minimum intensities of acceptable vacuum pressure followed by an over pressure are involved, a cycle of at least five applications of vacuum and over pressure are needed.
(5) A preferable single cycle of bale treatment would comprise a vacuum pressure application as low as -29" Hg gage prior to admission of treating fluid, followed by an over pressure of 500 psig.
(6) Single cycle bale treatment time is estimated at six minutes or less, with an additional five minutes required for subsequent cycles.
Whereas a convenient manner of practicing the invention in which the debonding liquid is caused to penetrate into the interior of a waste material bale by extracting a substantial amount of air from a sealed chamber in which the bale is isolated by subjecting the chamber to a negative pressure environment prior to introducing liquid into the chamber after which the chamber containing sufficient liquid to submerge the bale is subjected to an over pressure of at least one atmosphere during which the liquid penetrates throughout the bale contents, the same result could be achieved by subjecting the bale to differential positive pressure environments, instead of a negative pressure followed by a positive pressure, in establishing a flow of liquid throughout the contents of the tightly compacted bale.
A basic feature of the invention, applicable as the initial operation in the recycling of baled waste material prior to initiating a defibration of fibrous matter in the bale, is establishing a wetting impregnation of the bale contents with a fiber swelling and debonding fluid by isolating the bale within a closed chamber and subjecting the closed chamber and contained bale to one or more cycles of liquid insertion under multiple pressure environments each comprising:
(1) establishing a first (preferably vacuum) pressure within the interior of the closed chamber,
(2) introducing into the pressurized chamber a sufficient amount of debonding liquid as submerges the bale,
(3) subjecting the interior of the liquid containing chamber to a second (preferably positive) pressure greater than the first pressure and
(4) maintaining the chamber containing the fluid and bale at the second pressure for a sufficient time as establishes a penetration of the liquid substantially throughout the interior of the bale.
After a thorough wetting impregnation of the bale with the swelling and debonding liquid, the bale is removed from the chamber and maintained in a quiescent condition for a sufficient time as establishes a debonding swelling of the waste paper article cellulosic fibers exposed to the debonding liquid after which the contents of the liquid impregnated bale are subjected to defibration and separation out of the swollen cellulosic fibers from the remaining bale reject contents. If the baled waste paper articles comprise fibrous material sufficiently contaminated or coated with a fiber barrier contaminant that the bale reject contents contain a significant amount of non-debonded fibers, this bale reject portion preferably is again subjected to one or more cycles of liquid impregnation under multiple pressure environmental conditions and further defibration recycling.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic diagram illustrating waste material bale multiple pressure liquid impregnation apparatus and process of the invention.
FIG. 2 is schematic diagram illustrating apparatus and method for recycling the contents of the waste material bale impregnated in accordance with FIG. 1.
DESCRIPTION OF THE INVENTION
First referring to FIG. 1, representing a schematic arrangement by which the bale multiple pressure liquid impregnation aspect of the invention can be carried out, an infeed conveyor system 10 is arranged in a manner to transport waste material bales 11 supported in a shallow tray 36 into the interior of a vacuum treatment chamber 12 through an access door 13, illustrated in dotted lines in its open position, and an outfeed conveyor system 14 is arranged to remove the liquid impregnated bale 15 from within the treatment chamber 12 for further processing in the manner subsequently described in FIG. 2. Treatment chamber 12 connects through a line 17 and a three-way reservoir valve 18 to a treatment liquid reservoir 16 and through the three-way valve 18 and drain line 35 to a treatment fluid make-up tank 22. To minimize the interior dimensions of the treatment chamber 12 in accommodating the largest bale intended for treatment, the treatment chamber capacity can be supplemented by connecting through a line 20 to an overflow header 19. However, the header can be eliminated if the treatment chamber is of sufficient size to accommodate the total volume of treatment liquid that would be required for the treatment cycles discussed herein. Various other obvious alternative arrangements can be utilized to ensure that a sufficient amount of treatment liquid is maintained in the treatment chamber to submerge the bale during the treatment cycles. Reservoir 16, having an atmosphere connection line 21, is connected to a treatment fluid make-up tank 22 through a replenishing line 34 containing a valve and pump assembly 23. A rinsing fluid tank 22a is connected to the treatment chamber 12 through a line containing a shut-off valve 22b. The suction side of a vacuum pump 24 connects to the interconnected header 19 and treatment chamber 12 through line 25 containing a shut-off valve 26. A second source 61 of a treatment gas, typically of the nature of ammonia or oxidizing gas also connects into line 20 through line 61a and valve 61b. A high pressure pump 27 with its suction side connected to the liquid reservoir 16 through line 28 connects through its pressure side and a three-way pressurizing valve 30 through line 29 to the interconnected header 19 and treatment chamber 12, the third side 31 of the three-way pressurizing valve connecting to atmosphere when set to the third position. A bale stabilizing arm 32 supported within the treatment chamber 12 for vertical movement by an actuating mechanism 33 is adjustable vertically into and out of contact with a bale contained in the treatment chamber.
Referring now to FIG. 2, representing a schematic arrangement by which the bale of waste material impregnated in the manner of the invention represented in FIG. 1 can be optimally recycled for the recovery of a maximum amount of cellulosic fibers of high quality from all types of paper articles. The waste material bale 15, previously subjected to multiple pressure debonding fluid impregnation in the manner of FIG. 1, is supported in a shallow tray 36 for removal and transportation by the outfeed conveyor system 14 and deposited into a fiberizer or fiber dispersion unit 37 containing water or other suitable pulping liquid supplied from a suitable source (not illustrated). The fiberizer is a conventional type in which sufficient agitation is generated in the pulping liquid as separates or prepares for separation the waste paper fibers that have become swollen and debonded in the liquid impregnated bale but the agitation is not sufficient to damage the fibers significantly or significantly diminish the size of agglomerations of contaminated fibers or segments of contaminants such as foils, laminates, etc. that become debonded from the fibrous material in the vacuum treatment chamber 12. A typical fiberizer tank 37 contains a rotor 38 mounted for rotation substantially flush with an interior sidewall of the fiberizer tank to prevent entanglement with segments of contaminated material. Preferably a vertical baffle 39 extends downwardly into the interior of the fiberizer tank 37 between the rotor 38 and the outlet at the top of the fiberizer leading into the intake 40 of a pulp separator 41 conveniently of the type of a Trommel Screen. The pulp receiver 42 of the separator 41 connects to the suction of a slurry recovery pump 43 which discharges into a pulp cleaning or processing system from which reclaimed paper products are produced. A waste reject conveyor 44 extending from the waste discharge conduit 45 of the pulp separator 41 has a two-position diverter 46 which channels reject waste material at the exit end of the conveyor 44 either into the intake 48 of a second pulp separator 49 or into a shredder 47 that empties into the intake 48 of the second pulp separator 49, also of the nature of a Trommel Screen which has a pulp receiver 50 connecting to the suction of a slurry pump 51 that discharges into the pulp cleaning or processing system. The waste outlet 52 of the second separator connects through a waste discharge line 53 to a hydraulic liquid extractor and baler 54 which both extracts liquid from the reject waste material contained in the extractor and compacts the extractor contents into a semi-wet reject bale 55. A discharge end of the extractor-baler 54 communicates with a disposal conveyor 56 at the discharge end of which is a two-position diverter 57 which channels the reject bale 55 either to a waste disposal destination 58 (e.g., landfill) or to a secondary recycling conveyor system 59 arranged to redeposit the reject baled material 55 onto the infeed conveyor system 10 of the vacuum-pressurizer liquid treatment system of FIG. 1 or a CTDS unit 60 subsequently discussed. Inasmuch as a second vacuum-pressurized liquid treatment of a reject bale 55 received into the treatment chamber 12 from the secondary bale recycling conveyor system 59 would decrease the productive capacity of the vacuum-pressurized liquid treatment system of FIG. 1, alternatively the secondary bale recycling conveyor system 59 can be adapted to divert selected reject baled material 55 into a "combined-treatment-dispersion-separation" (CTDS) unit 60 of the type described in our U.S. Pat. No. 5,271,805 arranged to discharge separated pulp slurry into the second pulp separator intake 48 and reject materials into the extractor and baler 54.
Referring again to FIG. 1, the cycle for establishing the multiple pressure or vacuum-pressurizing impregnation treatment of an untreated bale 11 is initiated by the introduction into the treatment chamber 12 of the bale on shallow tray 36 and closing the chamber door 13 to seal the chamber after which the vacuum pump valve 26 is opened to connect the suction side of the vacuum pump 24, which most conveniently can be continuously operated, to the interconnected header 19 and treatment chamber 12 which have been isolated from the remainder of the system by placing the three-way reservoir valve 18, the three-way pressurizing valve 30 and the rinsing valve 22b in a closed position, thereby establishing a vacuum pressure within the bale containing treatment chamber 12 to the capacity of the vacuum pump. During this evacuation period the reservoir 16 can conveniently be resupplied with a treatment fluid from the make-up tank 22 through the connecting line 34 and its normally closed valve and pump assembly 23. The treatment fluid can be any of the well-known fiber swelling and debonding fluids of the nature of plain water or preferably an alkaline fluid having a pH of about 7.0-11.5 of the nature of dilute ammonium hydroxide or fluid containing an oxidizing agent, etc. Obviously, stronger treatment fluids are required when the fibrous matter comprising the waste paper articles is heavily contaminated or coated with a fluid barrier contaminant. During or prior to evacuating air from the treatment chamber 12 the stabilizing arm 32 is lowered into contact with the bale to clamp it into a fixed position by activating the arm actuating mechanism 33. Following air evacuation from the interconnected header 19 and treatment chamber 12 to substantially the capacity of the vacuum pump 24, the three-way reservoir valve 18 is set to an open position interconnecting the treatment chamber 12 and the reservoir 16 whereby treatment liquid from the reservoir 16 flows through the line 17 filling the treatment chamber 12 and header 19.
Following evacuation and filling of the treatment chamber 12 with treatment liquid, atmospheric over pressure is established in the fluid filled treatment chamber 12 and header 19 by closing the three-way reservoir valve 18 and the vacuum pump valve 26 and positioning the three-way pressurizing valve 30 to its third position 31 atmosphere connection, thereby establishing an atmospheric over pressure in the liquid filled treatment chamber 12 containing the submerged bale through the line 29 connected into the header 19. If a super atmospheric over pressure is to be established in the liquid filled treatment chamber 12 containing the submerged bale, the three-way reservoir valve 18 and vacuum pump valve 26 are closed to isolate the treatment chamber, the high pressure pump 27 is activated and the three-way pressurizing valve 30 is opened to connect the discharge of the high pressure pump 27 into the header 19 and treatment chamber 12 through the line 29, the high pressure pump drawing liquid from the reservoir 16 through line 28.
If the bale conditioning treatment is to comprise a single evacuation-pressurizing cycle, after the over pressure has been applied for a sufficient time that the treatment liquid penetrates throughout the bale and its voids to substantially the extent the over pressure can provide, excess treatment liquid may be drained from the treatment chamber 12 into the make-up tank 22 by setting the three-way reservoir valve 18 to its third position connecting line 17 into the drain line 35 leading into the make-up tank 22 and setting the three-way pressurizing valve 30 to its atmospheric opening side 31 with the vacuum pump valve 26 closed and the high pressure pump deactivated. After drawing excess liquid from the treatment chamber 12 the bale stabilizing arm 32 is raised, the treatment chamber door 13 opened and the liquid impregnated bale 15 removed by the outfeed conveyor system 14 and transported into the recycling processing system of FIG. 2 in which the swollen and debonded fibers of the waste paper in the impregnated bale 15 are separated from the non-fibrous contaminated matter of the bale contents in the manner subsequently described with respect to FIG. 2. If the nature of the waste paper articles in the bale are such that multiple vacuum-pressurizing cycles are considered necessary to obtain the desired degree of debondment of the paper fibers from contaminants, after the initial application of over pressure, a second or more evacuation-pressurizing cycles are initiated by utilizing the same procedure discussed for the first cycle prior to draining excess fluid from the treatment chamber 12 and removal of the impregnated bale. Also prior to removal of the liquid impregnated bale from the treatment chamber and before or after excess treatment fluid is drained into the make-up tank, the impregnated bale can be rinsed with a suitable rinsing fluid or second type of treating fluid drawn from the contents of the rinsing tank 22a by placing the vacuum pump valve 26 in its open position connecting the suction side of the operating vacuum pump 24 through line 25 into the interconnected header 19 and treatment chamber 12 and opening the rinsing tank valve 22b, the reservoir connecting valve 18 being closed.
It should be understood that the devices and procedures described above are illustrative only of the basic aspects of the invention and many other devices and procedures can be utilized in establishing the multiple pressure environments of the invention to which the baled waste material is subjected in practicing the invention. For instance, the discharge side of the vacuum pump can be connected through valving and connection arrangements that are obvious to those skilled in the art as would apply a low degree of over pressure greater than atmospheric onto the liquid filled treatment chamber.
Referring again to FIG. 2, the bale 15 impregnated with the swelling and debonding liquid is maintained in a quiescent state on the outfeed conveyor system 14 for a sufficient time for the debonding liquid to come into contact with and be sorbed by exposed fibers of the waste paper articles in the bale after which the waste bale 15 is deposited in the fiberizer 37 in which agitation of the fiberizer pulping fluid initiates a separation between the swollen waste paper fibers and between these fibers and agglomerate masses of contaminated fibers and non-fibrous contaminant masses debonded from the fibrous material by the vacuum-pressurizing conditioning treatment previously described. The agglomeration of separated fibers and non-debonded fiber material and integral masses of contaminants agitatively separated in the fiberizer 37 flow under the fiberizer baffle 39 and out of the fiberizer under the pressure generated by the fiberizer rotor 38 into the accumulator 40 of the screen separator 41 in which the agglomerate wetted masses are separated into the two components of: (1) a fiber-liquid slurry collected in the separator receiver 42, which is discharged through pump 43 to a source of further pulp refining, and (2) rejects comprising wetted masses of contaminant containing or coated fibrous material and non-fibrous contaminants that flow through the separator discharge line 45 and are deposited on the waste conveyor 44. The wetted reject masses deposited on the waste conveyor 44 may contain a substantial amount of fibers with some degree of contamination and from which separation is possible, e.g., plastic bags filled with relatively uncontaminated paper articles, contamination coated or impregnated paper, etc. If the reject masses on the conveyor 44 include paper articles of a nature that the surfaces are coated or the articles are protected by some type of fluid barrier, the diverter 46 at the end of the conveyor is positioned to channel the reject mass into the shredder 47 in which the reject mass material is sufficiently severed to expose end surfaces to liquid penetration after which it is deposited in the accumulator 48 of the second separator 49. Otherwise, the diverter 46 is positioned to channel the reject masses on the conveyor directly into the accumulator 48 of the second separator 49 in which the material is segregated into the same two components as in the first separator 41 of a fiber-liquid slurry collected in the receiver 40 from which pump 51 discharges the slurry into the pulp cleaning and processing system and a reject mass flowing from the second separator waste outlet 52 through the waste discharge line 53 into the hydraulic liquid extractor 54 which extracts liquid and presses the reject mass into a compacted semi-wetted bale 55 which is deposited onto the disposal conveyor 56. If the compacted wetted bale 55 has a significant paper fiber content of about 5% or more, as would make it worthwhile to reprocess the contents of the compacted wetted bale 55 for a second time through the vacuum-pressurizing treatment conditioning in the treatment chamber 12 displayed in FIG. 1, the disposal conveyor diverter 57 can be positioned to channel the semi-wetted reject bale 55 onto a secondary bale recycling conveyor system 59 which deposits the bale onto the infeed conveyor system 10 of the vacuum-pressure treatment system of FIG. 1 from which the wetted reject bale is again processed for extraction of paper fibers in the same manner as previously described. If reintroduction of the semi-wetted reject bale 55 into the vacuum-pressure impregnation system of FIG. 1 is determined to overload the productive capacity of that system and the semi-wetted reject bale 55 is diverted by the secondary bale recycling conveyor system into the CTDS unit, this unit pumps the pulp slurry recovered from the bale into the accumulator 48 of the second separator unit 49 and deposits the remaining contaminated masses into the hydraulic liquid extractor baling unit 54.
The baled waste material, after being subjected to liquid impregnation under the described cycles of multiple pressure environmental conditions, is of a nature that moderate agitation of the bale causes the contents to become dispersed into a flotsam comprising a slurry of liquid suspended cellulosic fibers and other small particles mixed with chunks of contaminated, non-debonded fibrous material, contaminant coatings separated from fibrous material and non-fibrous contaminants largely retaining their original dimensions. Due to the lack of an appreciable diminution in the size of contaminant containing bonded fibrous material and contaminant matter contained in the flotsam created in and discharged from the fiberizer 37, the slurry that passes through the screen of the separator and collected in the receiver 42 contains small amounts of contaminant particles which results in a low degree of clogging of the screen separators. Due to the nature of the flotsam produced in the fiberizer and the rejected matter discharged from the screen separator or being processed through the recycling system, this reject matter does not flow through pumps in being processed, but flow establishing means, such as the flush mounted rotor 38 of the fiberizer are utilized in causing the liquidized reject flotsam to pass through the recycling system. Accordingly, the usual problem encountered in recycling systems of clogged pumps is not present in the system of the described invention. It should be further recognized that the number of screen separators incorporated in a recycling system of the nature of this invention can vary in accordance with the nature of the types of waste paper that are contained in the waste material.
It should be further understood that the foregoing disclosure involves typical embodiments of the invention and that numerous modifications or alterations may be made therein without departing from the spirit and scope of the invention as set forth in the appendant claims.
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An improved method of processing baled waste material containing waste paper having fibers contaminated to various degrees for recovering usable cellulosic fiber pulp from the bale in which the bale contents are impregnated with a fiber swelling and debonding fluid by enclosing the bale within a closed chamber and subjecting the chamber and contained bale to multiple pressure environmental conditions, that preferably includes a vacuum, while submerging the bale in the debonding fluid. The impregnated bale contents are allowed to soak for a sufficient period that the lesser degree contaminated fibers become swollen after which the bale is subjected to a sufficiently low degree of pulping agitation as initiates separation of the swollen fibers without significant damage to the fibers and which does not significantly decrease the sheet size of higher degree contaminated bonded fibers and other contaminants. The agitated bale contents are separated in a screen separator into a pulp containing slurry and a reject mass of higher degree contaminated, unswollen fibers and contaminants. If the reject mass contains a significant degree of fibrous material, it is compressed into bale form and again subjected to a multiple pressure liquid impregnation treatment in a closed chamber after which the multiple pressure impregnated bale is subjected to the same or similar recycling operations in separating out the fiber pulp slurry.
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BACKGROUND OF THE INVENTION
[0001] The present invention relates to a method and apparatus for the production of tubing, rods and the like from crystalline quartz or other glass like materials. Particularly, this invention relates to a method and apparatus for use in the production of elongated quartz members from a silica melt. The present invention is particularly directed to the manufacture of fused silica tubes for use in the manufacture of optical fibers.
[0002] Various types of elongated members have been formed continuously by melting of quartz crystal or sand in an electrically heated furnace whereby the desired shape is drawn from the furnace through a suitable orifice or die in the bottom of the furnace as the raw material is melted. One apparatus for continuous production of fused quartz tubing, for example, is a tungsten-lined molybdenum crucible supported vertically and having a suitable orifice or die in the bottom to draw cane, rods, or tubing. The crucible is surrounded by an arrangement of tungsten heating elements or rods which heat the crucible. The crucible, together with its heating unit, is encased in a refractory chamber supported by a water-cooled metal jacket. The crucible is heated in a reducing atmosphere of nitrogen and hydrogen.
[0003] An alternative apparatus provides fused quartz tubing by feeding natural quartz crystal into a refractory metal crucible heated by electrical resistance under a particular gas atmosphere to reduce the bubble content. The bubbles formed by gas entrapment between crystals and the molten viscous mass of fused quartz do not readily escape from the molten glass and, hence, remain as bubbles or lines in the product drawn from the fused quartz melt. By substituting a melting atmosphere gas which readily diffuses through the molten material (such as pure helium, pure hydrogen or mixtures of these gases) the gas pressure in the bubbles was reduced and thereby the bubble size was reduced. This process uses a mixture of 80% helium and 20% hydrogen by volume.
[0004] In a further alternative method, a product is obtained by continuously feeding a raw material of essentially pure silicon dioxide in particulate form into the top section of an induction-heated crucible, fusing the raw material continuously in an upper-induction heat zone of the crucible in an atmosphere of hydrogen and helium while maintaining a fusion temperature not below approximately 2050° C. The fused material in the lower zone of the crucible is heated by separate induction heating means to produce independent regulation of the temperature in the fused material. The fused material is continuously drawn from the lower zone of the crucible through forming means in the presence of an atmosphere of hydrogen containing a non-oxidizing carrier gas.
[0005] Unfortunately, most of the refractory metal and non-metal materials used in the crucibles of the above-described apparatus are undesirable impurities if present in the drawn silica article. Such refractory material contamination causes discoloration and occlusions in the silica glass. Furthermore, the presence of refractory material particles (e.g. 1-10 μm) can degrade the strength of the resultant silica article. Moreover, the particles become a flaw in the drawn article that can cause the strand to break.
[0006] Accordingly, there is a need in the art to reduce contamination of fused glass occurring from the refractory materials used in constructing the furnace. This need has increased recently as semiconductor and fiber optics manufacturing processes, a primary use for the glass products obtained from the subject process, have required higher levels of purity and performance.
[0007] Unfortunately, because the furnace is typically constructed of the refractory materials, the manufacturing plant is usually contaminated therewith. Accordingly, even a furnace having melting and drawing zones insulated from refractory materials cannot fully prevent contamination. It would therefore be desirable to have available a method for removing and/or reducing the effect of refractory materials contamination on the strength of the resultant silica article.
BRIEF SUMMARY OF THE INVENTION
[0008] In an exemplary embodiment of the invention, a method for forming an elongated fused quartz article is provided. The method generally comprises feeding a silica or quartz (SiO 2 ) material into a furnace. The SiO 2 material is fused in a melting zone of the furnace under a gas atmosphere including a carrier gas and at least one oxidizing gas. The article is then drawn from the furnace.
[0009] In an exemplary embodiment of the invention, a furnace for melting of the silica and subsequent drawing into a desired shape is comprised of a body having an outer surface constructed of a refractory metal and including a inner lining in at least the melt zone of the furnace of a non-reactive barrier material. The inner lining is preferably formed of rhenium, osmium, iridium, platinum or mixtures thereof. Preferably, the furnace will include an inlet tube for introduction of a carrier gas and an oxidizing gas to the melt zone.
[0010] The present crucible construction provides a number of advantages over the prior art. Particularly, furnaces constructed with rhenium, iridium, platinum and/or osmium lined crucibles produce products with much lower levels of refractory metal in the solution. For example, the metal dissolved in the silica can be reduced to below 10 ppb, preferably below 1 ppb, and preferably below the current level of detection via NAA. This reduced amount of refractory metal contamination in the silica melt improves the chemical composition of the silica glass allowing for a decrease in discoloration and surface haze. Furthermore, utilization of a furnace equipped with a crucible including the non-reactive lining allows operation at optimum temperature ranges. Operation at these optimum temperatures may achieve better fining. Moreover, operation at optimum fusion temperatures will increase solubility of gaseous species in the raw material, thus reducing airline defects in the drawn products.
[0011] Similarly, the present inventive crucible will also help to further reduce the presence of haze and discoloration in the resultant glass products. In addition, the present inventive furnace allows for the use of an oxidizing atmosphere in the melt zone. Previously, oxidizing agents in the melt zone were avoided because of their negative impact on the refractory walls of the crucible, particularly on tungsten and molybdenum.
[0012] It should be noted that the terms “quartz” and “silica” are used interchangeably throughout this application, both being directed generally to the compound SiO 2 . Nonetheless, the present invention encompasses the use of any raw material introduced to the melting furnace, including but not limited to natural silica/quartz and synthetic silica.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The structure, operation and advantages of the present preferred embodiment of this invention will become further apparent upon consideration of the following description, taken in conjunction with the accompanying drawings, wherein:
[0014] FIG. 1 is a longitudinal sectional view of a furnace of the present invention;
[0015] FIG. 2 is a schematic view of a furnace demonstrating the present inventive construction; and
[0016] FIG. 3 is a cross-sectional view of a typical optical fiber.
DETAILED DESCRIPTION OF THE INVENTION
[0017] In one of its preferred embodiments, the fused quartz product of the present invention can be formed in a furnace configuration having the features shown in FIG. 1 . The furnace has a general cylindrical shape. Preferably, an elongated cylindrical melting crucible 10 constructed of a refractory metal layer 11 , such as tungsten or molybdenum as well as combinations thereof, is used. The melting crucible 10 further includes a lining of rhenium 13 over the refractory metal layer 11 .
[0018] A purified sand raw material is fed through a top opening 12 into a melt zone 14 of the crucible member. The top opening 12 is provided with movable closure means 16 , such as a trapdoor which can be kept closed except for observing the level of the melt 18 and during feeding of the raw material into the crucible. Automatic feeder means 20 are provided at the top opening of the crucible member to maintain a predetermined level of the raw material in the crucible. The feeder includes a discharge tube 22 having its outlet opening located in the crucible 10 so as to provide the raw material in an upper region where melting takes place, a purge gas inlet tube 24 and reservoir means 26 which contains a supply of the raw material being fed automatically to the discharge tube.
[0019] The purge gas being supplied to the feeder helps eliminate gases contained in the raw material which could otherwise form bubbles in the fused quartz melt which cannot thereafter be removed or minimized in a manner to be described in part immediately hereinafter. The composition of the purge gas is generally a gas mixture of hydrogen and helium in the volume ratios 40-100% hydrogen and 60-0% helium.
[0020] The lower portion 28 (a drawing zone) of the crucible 10 includes an annular ring 30 having central opening 32 through which the elongated fused quartz member is continuously formed by drawing the viscous material through the opening. A core 34 is centrally disposed in the opening 32 and extends below—but could extend above—the means of forming tubing from the viscous material being drawn from the melt. As known by the skilled artisan, the position of the core can be shifted as necessary to produce the desired size of extrudate. Support element 35 is affixed to the wall of the crucible and provides rigid support of the core which helps to maintain a constant size opening from which the product is being drawn. The core is fabricated with a hollow interior 36 which is connected to inlet pipe 38 so that a supply of non-oxidizing gas can be furnished as a forming atmosphere while the tubing 40 is being drawn.
[0021] A second inlet pipe 42 supplies what can be a mixture of hydrogen in a non-oxidizing carrier gas such as argon or nitrogen in volume ratios 1-20% hydrogen and 99-80% carrier gas as a protective atmosphere which surrounds the exterior refractory metal wall 11 of the crucible 10 . This supply of gas is provided to annular space 44 which provides a housing means for the crucible and includes a central bottom opening 46 providing exhaust means from the cavity for the gas in a manner which envelops the exterior surface of the elongated fused quartz member 40 being drawn from the furnace. The exterior wall of the annular space comprises a refractory cylinder 48 which in combination with exterior housing 50 of the furnace construction serves as the container means for the induction heating coils of the apparatus. More particularly, a concentric passageway 52 is defined between the exterior wall of the refractory cylinder 48 and the interior wall of housing 50 in which is disposed two helical-shaped induction heating coils 54 and 56 supplying separate heating sources for the upper and lower zones of the crucible, respectively. Of course, additional coils may be employed as governed by the size of the furnace, for example, it may be beneficial to include additional coil(s) in the finish zone. In any case, the heating sources and the power supplies thereto can be of conventional construction.
[0022] A third supply pipe 58 is located in the top section of exterior housing 50 , passing into the crucible 10 , allowing a gas mixture to be fed to the melt zone 14 of the crucible. This gas mixture is generally an inert carrier gas in combination with an oxidizing gas. The preferred carrier gas is selected from hydrogen, helium and the other noble gases and the preferred oxidizing gas is water vapor or air. Preferably, in the case of hydrogen and water vapor, the oxidizing gas fed to the melt Zone 14 will be a hydrogen with a dew point of greater than 30° C., more preferably, greater than 50°.
[0023] The preferred form of the present invention includes the rhenium lining 13 which enables the introduction of the oxidizing gas. Moreover, since the refractory metals forming the walls of the crucible are usually rapidly oxidized and degraded at the temperature of furnace operation, it is beneficial to protect them from the oxidizing atmosphere in the melt zone. Of course, any material suitable to this purpose can be used, such as rhenium, osmium, iridium and mixtures thereof.
[0024] In prior processes, the presence of hydrogen in the melt zone to protect the refractory materials also resulted in the Mo/W oxides being reduced and remaining in the melt as metal particles causing a loss of strength in the drawn articles. The presence of oxidizing gas (e.g. water vapor) will keep or convert the refractory metal oxides to that complexed state, resulting in their discharge as volatile gases or becoming solubilized into the melt with little negative impact.
[0025] Of course, the present inventive method and use of a non-reactive crucible lining in the melt zone is not limited to the furnace or crucible shown in FIG. 1 .
[0026] In accordance with carrying out the process of the present invention in the above-described apparatus, a natural silica sand having a nominal particle size of −50 mesh U.S. screen size which has been purified by chemical treatment to the nominal impurity content below is supplied to the top opening of the crucible member in the apparatus. Alternatively, a synthetic silica can be used.
RAW MATERIAL Impurity Natural (p.p.m.) Synthetic (p.p.m.) Fe 2 O 3 1 0.07 TiO 2 2 <.02 Al 2 O 3 20 100 CaO 0.4 <.01 MgO 0.1 <.05 K 2 O 0.6 0.1 Na 2 O 0.7 0.1 Li 2 O 0.6 <.05 B <0.2 — ZrO 2 <1.0 <.02
[0027] The above raw material is provided to the crucible member which has been heated in excess of 2050° C. while also being supplied with the hydrogen and helium gas mixture hereinbefore specified. After a predetermined melt level of fused quartz has been established in the crucible and the molten material caused to flow by gravity through central bottom opening 32 in the crucible member, tubing or rod is then drawn continuously by the drawing machine (not shown) in the presence of a forming gas atmosphere as hereinbefore specified. The above-described furnace is operated in connection with conventional tube or rod drawing machinery which has been omitted from the drawing as forming no part of the present invention. In any continuous drawing of tubing/rod in the foregoing described manner, the electrical power being supplied to the lower heating coil 56 is typically maintained at a lower level than the electrical power being supplied to the upper heating coil 54 in order to lower the temperature of the material as it is being drawn to below a temperature of 2050° C. However, the use of a non-reactive lining in the finish zone can allow higher temperature operation if desired.
[0028] As stated above, the internal surface of the furnace crucible 10 includes a non-reactive (e.g. rhenium, osmium, platinum or iridium) sheet or coating 13 . The coating 13 may be applied to the refractory metal layer 11 by chemical vapor deposition, electrolysis, plasma spray or any other technique known to the skilled artisan (hereinafter referred to as “chemical bonding”). The non-reactive layer 13 may also be physically attached to the refractory metal layer 11 by attaching a sheet directly to the wall of the crucible with rivets, bolts, screws, etc., preferably constructed from the same or similar material as the non-reactive lining itself. Alternatively, a properly shaped rhenium sleeve can be inserted into the crucible. In fact, a combination of coating or lining methods may be used depending on the geometric complexity of the segments comprising the crucible assembly.
[0029] Referring now to FIG. 2 , an alternative embodiment of the present invention is demonstrated. Moreover, a sealed cup of rhenium 113 is located around and above the melt/fusion zone 115 . This position of the cup 113 shields the tungsten walls 117 of the crucible from the atmosphere 119 in the melt zone 115 . This protection is supplemented by feeding a dry hydrogen gas through tube 121 to the space 123 between cup 113 and walls 117 . A tube 125 is provided to feed wet hydrogen into the melt zone 115 , and a tube 126 is provided to exhaust wet hydrogen gas. Of course, proper seals are provided between tube 125 and sand feed tube 127 to create a gas barrier within cup 113 . As is conventional in the art, a layer of insulation 129 is disposed between tungsten walls 117 and the induction heating coils 131 . As shown in this embodiment, feed sand 133 is beneficially in a wet hydrogen environment 119 as it fuses into a molten state 135 for eventual product forming.
[0030] Referring now to FIG. 3 , an optical fiber of the present invention is shown, comprising an optical fiber core 137 surrounded by a sheath 139 of silica formed via the present inventive process.
[0031] While the invention has been described by reference to preferred embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements without departing from the scope of the invention. In addition, any modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but the invention will include all embodiments falling within the scope of appended claims.
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A crucible for melting a silica for fusion of said silica into a desired shape. The crucible having a main body with inner and outer surfaces comprised of a refractory material. In addition, at least a portion of the inner surface includes a barrier layer comprised of a material selected from rhenium, osmium, iridium, and mixtures thereof. An inlet tube to the crucible being provided to supply an oxidizing gas to a melt zone.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a micromechanical device, which includes at least two sensor elements, an evaluation wafer, and at least two cavities having different gas pressures.
[0003] 2. Description of the Related Art
[0004] Such a micromechanical device is known, for example, from the published German patent application document DE 102006016260 A1 and allows multiple different sensor systems, having different requirements for the atmosphere surrounding them, to be combined in one micromechanical device. The different sensor systems, typically an acceleration sensor and a rotation rate sensor, are situated in different cavities and include a sensor element, preferably a seismic mass. For such micromechanical devices, it is generally provided that the different sensor systems are manufactured at the same time, i.e., in one method step, on a substrate, whereby particularly small and cost-effective combinations of different sensor systems are implementable in one single micromechanical device. The technical requirement exists for the affected micromechanical devices that the sensor systems are to be operated under the gas pressure provided in each case for them, which is different in most cases. Specifically, for example, while a preferably low gas pressure (approximately 1 mbar) is desirable for a rotation rate sensor, so that the resonant driven seismic mass of the rotation rate sensor only experiences a slight damping, acceleration sensors are preferably operated at a gas pressure which is approximately 500 times higher. The related art typically uses getter materials to set the desired gas pressure, which differs from cavity to cavity. This getter material is, for example, introduced into the cavity for which a lower pressure is provided, and is capable in an activated state of capturing gas molecules, whereby the gas pressure in the cavity is reduced. The getter material is typically activated in that the temperature exceeds a threshold value. The use of additional getter materials, which are therefore linked to additional costs, during the production of the micromechanical device has proven to be a disadvantage.
[0005] In addition, it is desirable to dimension the electrical connection between the sensor system and the evaluation circuit in such a way that the micromechanical device is not enlarged further and the electrical signal path between sensor system and evaluation circuit is preferably short. If the relevant electrical connection is selected to be excessively large, it is therefore to be expected that interfering influences may act from the outside on the signal path and worsen the signal-to-noise ratio. It is therefore the object of the present invention to provide a micromechanical device and a cost-effective method for manufacturing a micromechanical device, the micromechanical device having at least two cavities having different gas pressures. The present invention is additionally directed to providing a micromechanical device, in which the sensor system is connected to the evaluation circuit via a very short, electrically conductive signal path.
BRIEF SUMMARY OF THE INVENTION
[0006] The object is achieved by a micromechanical device including a sensor wafer, at least one intermediate wafer, and an evaluation wafer, the micromechanical device having a main plane of extension, the sensor wafer, the intermediate wafer, and the evaluation wafer being stacked in such a way that the intermediate wafer is situated between the sensor wafer and the evaluation wafer. In general, multiple such micromechanical devices are manufactured in a shared manufacturing process, intermediate wafer, sensor wafer, and evaluation wafer extending over all micromechanical devices to be produced during the manufacturing process.
[0007] It is additionally provided according to the present invention that the evaluation wafer is an ASIC wafer, i.e., the evaluation wafer has an application-specific integrated circuit, which is provided to process or relay the items of information originating from the sensor wafer in the form of electrical signals.
[0008] Furthermore, it is provided according to the present invention that the sensor wafer and/or the intermediate wafer include(s) a first sensor element, preferably a first seismic mass of an acceleration sensor or a rotation rate sensor, and the sensor wafer and/or the intermediate wafer include(s) a second sensor element, which is spatially separated from the first sensor element, preferably a second seismic mass of an acceleration sensor or a rotation rate sensor. It is provided that the first sensor element is located in a first cavity, which is formed by the intermediate wafer and the sensor wafer, and the second sensor element is located in a second cavity, which is formed by the intermediate wafer and the sensor wafer. In particular, it is provided that the sensor element or the first seismic mass and the second seismic mass include electrodes which interact together with one or multiple further electrodes attached to the intermediate wafer and/or the sensor wafer, and therefore form a sensor system or a rotation rate sensor or acceleration sensor.
[0009] Furthermore, it is provided according to the present invention that a first gas pressure in the first cavity differs from a second gas pressure in the second cavity, and the intermediate wafer has at least one opening. It is provided that this opening is then part of an intermediate space, which is delimited both by the intermediate wafer and also by the evaluation wafer and also by the sensor wafer. Such an opening may expose the view from the evaluation wafer to the sensor wafer in a direction extending perpendicularly to the main plane of extension, for example. In an alternative specific embodiment, the opening may also, however, expose the view from the evaluation wafer to the sensor wafer if the viewing direction does not extend perpendicularly to the main plane of extension, but rather is inclined at an angle thereto (i.e., at an angle to the direction extending perpendicularly to the main plane of extension), the angle being less than 90°. In particular, the provided opening of the intermediate wafer is capable of delimiting individual subregions of the intermediate wafer from one another. The micromechanical device according to the present invention has proven to be advantageous in relation to those from the related art in that the micromechanical device does not have getter material and therefore the additional costs arising due to the getter material are avoided. In one preferred specific embodiment, the intermediate wafer has convexities, on the side facing toward the sensor wafer, in the area of the first and/or the second cavity, to guarantee or provide a certain movement freedom to the sensor element. In one particularly preferred specific embodiment, it is provided that the micromechanical device has multiple intermediate wafers. In addition, it is provided for another specific embodiment of the present invention that the evaluation wafer has a thickness of 30 μm-150 μm. Using such a thin evaluation wafer it is possible to design the sensor wafer as sufficiently thick that occurring mechanical stresses (for example, induced by different thermal expansions between the micromechanical device and a circuit board on which the micromechanical device is situated) advantageously do not have an effect on the sensor element, because the sensor element is anchored in the thick (150 μm-1000 μm) and stable sensor wafer.
[0010] In another specific embodiment of the present invention, it is provided that at least one opening of the intermediate wafer is situated between the evaluation wafer and the second cavity.
[0011] In one particularly preferred specific embodiment of the present invention, it is provided according to the present invention that the intermediate wafer is made of an electrically conductive material, preferably a monocrystalline silicon wafer having a high level of doping (boron, phosphorus, arsenic, or antimony). In addition, it is possible that the intermediate layer includes one or multiple coatings. Using such a conductive intermediate wafer for the micromechanical device, it advantageously results that the micromechanical device, thanks to the openings in the intermediate wafer, has signal paths, i.e., electrically conductive connecting parts, which are independent of one another. The signal paths may also extend partially through the second cavity. Electrical signals may be transmitted with the aid of the signal paths from the sensor wafer to the evaluation wafer (preferably for evaluating the signals from the sensor system) or from the evaluation wafer to the sensor wafer (for example, to drive the seismic mass). It thus results that the signal path between evaluation wafer and sensor wafer is short in comparison to those which are known from the related art for micromechanical devices. In a particularly advantageous way, an electrically conductive signal path is thus implemented, which is less susceptible to interference in relation to electromagnetic radiation and parasitic capacitances in comparison to those micromechanical devices in which the electrical signals are transmitted via a longer signal path. In addition, the short signal paths contribute to the micromechanical device being able to be dimensioned as small as possible.
[0012] In another specific embodiment of the present invention, it is provided that a first atmosphere or a first gas or a first gas mixture in the first cavity differs from a second atmosphere or a second gas or a second gas mixture. The advantage thus results for the micromechanical device that optimum operating conditions provided for the first and/or second sensor elements may be set not only via the first and/or the second gas pressure, but may also be set by the first and/or second gas or gas mixture located in the first and second cavities. This could prove to be advantageous in particular if it is shown that the gas or gas mixture which is optimum or provided for the operation of the first sensor element in the first cavity is disadvantageous for the operation of the second sensor element in the second cavity (for example, because it has an unfavorable viscosity for the second sensor element in the second cavity).
[0013] In another specific embodiment of the present invention, it is provided that the first sensor element is a part or component of an acceleration sensor and the second sensor element is a part or component of a rotation rate sensor. The possibility thus advantageously results of combining a sensor which analyzes a translational movement and a sensor which analyzes a rotational movement in a single micromechanical device. It is similarly possible that the first sensor element is a part or component of a rotation rate sensor and the second sensor element is a part or component of an acceleration sensor.
[0014] In another specific embodiment of the present invention, it is provided that one or multiple sensor means are provided on the intermediate wafer, i.e., between the evaluation wafer and the sensor wafer. The sensor means may include a further sensor element or passive elements, for example, a capacitance, a coil, or a diode. In particular, such passive elements are provided there where they are to be protected from influences such as moisture and/or electrical fields. In one preferred specific embodiment of the present invention, the sensor means include a magnetic field sensor, which is situated on the intermediate wafer. The advantage thus results for the micromechanical device of including still more modules, for which an independent device would otherwise be required. Space may thus be saved, for example, on a chip carrier or a circuit board, on which the micromechanical device is situated together with other modules. In addition, it has proven to be an advantage that the sensor means is protected from moisture and electrical fields by the arrangement between evaluation wafer and intermediate wafer.
[0015] In another specific embodiment of the present invention, one or multiple stops are provided in the first and/or the second cavity. Such stops, which are preferably situated at defined points above the sensor element, advantageously allow the movement freedom of the first and/or the second sensor element (in particular the first and/or the second seismic mass) to be restricted, for example, to prevent spring fractures of the sensor element in the event of overload. In one alternative specific embodiment, it is provided that the first and/or the second sensor element has/have an anti-adhesive layer, in particular an organic anti-adhesive layer. Such a layer advantageously prevents the sensor elements from sticking to one another in the event of overload. In addition it is possible in another specific embodiment that the first and/or second cavity has/have both a stop and an anti-adhesive layer.
[0016] In another specific embodiment of the present invention, it is provided that the sensor wafer and/or evaluation wafer include(s) printed conductors, the sensor wafer having one or multiple first printed conductor(s) and the evaluation wafer having one or multiple second printed conductor(s). Together with the signal paths, which the intermediate wafer provides, the micromechanical device is advantageously capable of sending electrical signals directly from the sensor system of the sensor wafer to the integrated circuit of the evaluation wafer or vice versa, the intermediate wafer ensuring that at least one first printed conductor of the sensor wafer is electrically conductively connected to at least one second printed conductor of the evaluation wafer.
[0017] In another preferred specific embodiment of the present invention, it is provided that, on the evaluation wafer, an electrical terminal is situated on the side of the evaluation wafer facing toward the intermediate wafer or on the side facing away from the intermediate wafer. Such an electrical terminal is provided to connect the micromechanical device to the circuit board or the chip carrier. If the terminal is located on the side facing away from the intermediate wafer in particular, it is possible to use the micromechanical device in a bare die structure. In the bare die structure, the micromechanical device may be soldered directly onto the circuit board, whereby further packaging (for example, mold packaging), which is therefore linked to additional costs, of the micromechanical device may advantageously be omitted.
[0018] Another object of the present invention is a method for manufacturing a micromechanical device including a sensor wafer, an intermediate wafer, and an evaluation wafer, the micromechanical device having a main plane of extension, the sensor wafer, the intermediate wafer, and the evaluation wafer being stacked in such a way that the intermediate wafer is situated between the sensor wafer and the evaluation wafer, the evaluation wafer having at least one application-specific integrated circuit, and the sensor wafer and/or the intermediate wafer including a first sensor element and the sensor wafer and/or the intermediate wafer including a second sensor element, which is spatially separated from the first sensor element, the first sensor element being located in a first cavity, which is formed by the intermediate wafer and the sensor wafer, and the second sensor element being located in a second cavity, which is formed by the intermediate wafer and the sensor wafer, a first gas pressure in the first cavity differing from a second gas pressure in the second cavity, and the intermediate wafer having at least one opening in a direction perpendicular to the main plane of extension, the sensor wafer and the intermediate wafer being connected to one another by a first connection step and the intermediate wafer and the evaluation wafer being connected to one another by a second connection step, during the first connection step, the first gas pressure of a first gas or first gas mixture in the first cavity being set and, during the second connection step, the second gas pressure of a second gas or second gas mixture in the second cavity being set, the first connection step taking place chronologically before the second connection step. The method according to the present invention has the advantage over those which are known from the related art that it dispenses with getter materials, to implement a second gas pressure in the second cavity which differs from the first gas pressure in the first cavity. The first connection step is implemented in a first atmosphere, which includes the first gas pressure and the first gas or gas mixture, and the second connection step is implemented in a second atmosphere, which includes the second gas pressure and the second gas or gas mixture. In one preferred specific embodiment, the first gas or gas mixture corresponds to the second gas or gas mixture. In addition to the costs which are saved (by omitting getter materials), it has proven to be a further advantage of the method according to the present invention for manufacturing a micromechanical device that it is not necessary to heat the micromechanical device to activate the getter material, whereby the risk of temperature-related irreversible damage of one of the components of the micromechanical device is dispensed with.
[0019] In one alternative specific embodiment, a connection, which implements an electrical contact between intermediate wafer and evaluation wafer or sensor wafer, is used for the first connection step and/or the second connection step. With the aid of the contacts and an electrically conductive signal path, which the intermediate wafer has, electrical signals may be transmitted from the sensor wafer via the electrical contact to the evaluation wafer (preferably for evaluating the signals from the sensor system) or from the evaluation wafer via the electrical contact to the sensor wafer (for example, to drive the seismic mass). It thus results that the signal path between evaluation wafer and sensor wafer is short in comparison to those which are known from the related art for micromechanical devices. An electrically conductive signal path is thus implemented, which is particularly advantageously less susceptible to interference in relation to electromagnetic radiation and parasitic capacitances in comparison to those micromechanical devices in which the electrical signals are transmitted via a longer signal path. In addition, the short signal paths contribute to the micromechanical device not being enlarged.
[0020] In one particularly preferred specific embodiment, the electrical contact between intermediate wafer and evaluation wafer or sensor wafer is a eutectic AlGe connection. For such a eutectic AlGe connection, it is provided that an aluminum (Al) layer or a layer which is essentially made of aluminum is situated on the sensor wafer and/or the evaluation wafer on the sides facing toward the intermediate wafer, this layer applied to the sensor wafer or evaluation wafer advantageously being accompanied by the advantage of being compatible with known sacrificial layer etching methods (HF gas phase etching) or methods for depositing anti-adhesive layers. In addition, the aluminum layer may fulfill the task of an etch stop layer. A germanium (Ge) layer is situated on the intermediate wafer for the eutectic AlGe connection, the germanium layer being deposited, tempered, purified, and conditioned on the intermediate wafer at high temperatures, to improve the connection properties, without influencing the sensitive sensor elements. In one preferred specific embodiment, the germanium layer or the aluminum layer is applied to a silicon underlay or layer, whereby silicon may diffuse during the first and/or second connection step(s) into the eutectic AlGe connection and increase the melting temperature. A self-stabilizing system thus advantageously results, which is also still stable at temperatures above the eutectic temperature of AlGe. The silicon layer under the germanium layer is preferably selected to be thinner during the second connection step, to keep the melting temperature for the second connection step lower than for the first connection step, which advantageously prevents the AlGe connection of the first connection step from melting again during the second connection step and therefore causing weakening or shifting of the AlGe connection of the first connection step.
[0021] In one preferred specific embodiment of the present invention, the intermediate wafer has pre-structuring, i.e., the intermediate wafer already has recesses or stops before the first connection step, which are situated both on the side facing toward the evaluation wafer and on the side facing toward the sensor wafer and, after the first connection step, are part of the first cavity and/or the second cavity. On the one hand, stops in the first and/or the second cavity are used, for example, to prevent spring fractures of the seismic mass. On the other hand, convexities or recesses in the area of the first and/or the second cavity ensure that a certain movement freedom is guaranteed or made available to the sensor element. In addition, the advantage results that the internal pressure in the first and/or the second cavity may be reliably set with the aid of the recesses or convexities, even if degassing occurs during the first connection step and/or the second connection step.
[0022] In another preferred specific embodiment of the present invention, the intermediate wafer is structured after the first connection step and before the second connection step. This structuring preferably implements, using simple means, the opening in the intermediate layer, which is responsible for a small access to the second cavity. In addition, this structuring has the advantage that, in a simple way, parts of the intermediate wafer may be insulated from one another, whereby conduction paths form after the second connection step.
[0023] In another preferred specific embodiment of the present invention, the intermediate wafer is structured with the aid of an etching method, preferably using an anisotropic etching step or a trenching step. Trenches are etched around the electrical contacts in the intermediate wafer, to implement a ventilation access to the second cavity and insulate the electrical contacts from the intermediate wafer, whereby freestanding stamps (or small rods) arise in the intermediate wafer, which are mechanically coupled to the sensor wafer. If an aluminum layer was situated on the sensor wafer, it may advantageously act as an etch stop layer and partially prevent the etching into the sensor wafer. The AlGe connection, which implements the electrical contact between sensor wafer and intermediate wafer, is preferably smaller than the mechanical connection of the sensor wafer to a sensor system, which includes the sensor element. The advantage thus results that mechanical stress influences are reduced, which originate from the AlGe connection or from the stamp, after intermediate wafer, evaluation wafer, and sensor wafer have been layered one on top of another. In one alternative specific embodiment of the present invention, evaluation wafer and intermediate wafer include printed conductors, which are exposed with the aid of the etching method and via which the electrical signals may be conducted to the sensor structure. This may advantageously contribute to the reduction of the occurring mechanical stresses in the micromechanical device.
[0024] In another preferred specific embodiment of the present invention, the intermediate wafer is ground on the side opposite the sensor wafer after the first connection step, to make it thinner. Using a thin intermediate wafer, not only is the signal path shortened, but rather the extension of the micromechanical device in a direction perpendicular to the main plane of extension is advantageously reduced in comparison to the case in which the intermediate wafer is not ground thin. The extension of the micromechanical device may be reduced further, in that the evaluation wafer is ground thin on the side opposite the intermediate wafer after the second method step.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] FIG. 1 shows a schematic view of a micromechanical device according to a first specific embodiment.
[0026] FIG. 2 shows a schematic view of a micromechanical device according to a second specific embodiment.
[0027] FIG. 3 shows a schematic view of a micromechanical device according to a third specific embodiment.
[0028] FIGS. 4 through 7 show a method for manufacturing a micromechanical device.
DETAILED DESCRIPTION OF THE INVENTION
[0029] In the various figures, identical parts are always provided with identical reference numerals and are therefore generally also only cited or mentioned once in each case.
[0030] FIG. 1 shows a first specific embodiment according to the present invention of a micromechanical device 100 . It includes an intermediate wafer 1 , an evaluation wafer 11 , and a sensor wafer 5 , which have a shared main plane of extension and are stacked in such a way that intermediate wafer 1 is situated between evaluation wafer 11 and sensor wafer 5 . In the specific embodiment shown, a first sensor element 2 and a second sensor element 3 are part of sensor wafer 5 . First sensor element 2 and second sensor element 3 are preferably seismic masses, which are each part of a sensor system, such a micromechanical device 100 being able to include a plurality of (in this specific embodiment two) sensor elements 3 . In particular, first sensor element 2 is part of an acceleration sensor and second sensor element 3 is part of a rotation rate sensor. A first cavity 120 , which contains first sensor element 2 , has, according to the present invention, a different pressure than a second cavity 130 , which contains second sensor element 3 . Alternatively, a first atmosphere in first cavity 120 may also differ from a second atmosphere in second cavity 130 . Preferably, first and/or second cavity 120 and/or 130 include(s) one or multiple stops 16 , which are provided, for example, to prevent spring fractures of the seismic mass in the event of an overload. In the illustrated specific embodiment according to the present invention of micromechanical device 100 , intermediate wafer 1 includes openings or interruptions 140 , which are situated in such a way that they are, inter alia, an integral part of second cavity 130 . In addition, connection parts 6 , which are insulated from one another, and which connect evaluation wafer 11 and sensor wafer 5 , may form due to openings or interruptions 140 . The connection parts may also be situated inside the second cavity. If intermediate wafer 1 is made of an electrically conductive material, these connection parts 6 form conductor paths, via which evaluation wafer 11 and sensor wafer 5 are electrically conductively connected to one another, if an electrical contact 27 is provided for an electrical connection between intermediate wafer 1 and evaluation wafer 11 or sensor wafer 5 . In particular, conductor paths 6 may also electrically conductively connect printed conductors 23 , which are provided in evaluation wafer 11 or sensor wafer 5 , to one another, one or multiple printed conductors 23 in sensor wafer 5 being electrically conductively connected to the sensor system, and one or multiple printed conductors 23 in evaluation wafer 11 being electrically conductively connected to an application-specific integrated circuit, which is an integral part of evaluation wafer 11 .
[0031] With the aid of electrically conductive conductor paths 6 and printed conductors 23 , electrical signals may be transmitted from the sensor system to the application-specific integrated circuit. To connect micromechanical device 100 in an electrically conductive way to a circuit board or a carrier for micromechanical devices, a bond pad 30 is provided on the evaluation wafer.
[0032] The micromechanical devices according to the second and third specific embodiments of the present invention shown in FIG. 2 and FIG. 3 have essentially the same features as the micromechanical device according to the first specific embodiment. Therefore, the description of the parts which were already described in FIG. 1 will be avoided or simplified.
[0033] FIG. 2 shows a second specific embodiment according to the present invention of a micromechanical device 100 . In comparison to the first specific embodiment of the present invention, it has the feature that a sensor means 13 is situated on the intermediate wafer, on the side facing toward the evaluation wafer. Sensor means 13 may be a further sensor system, in particular a sensor means 13 , or a passive element. Sensor means 13 is preferably a magnetic field sensor. Independently of this sensor means 13 , micromechanical device 100 according to the second specific embodiment has an etch stop layer 18 , which is provided on sensor wafer 5 , to prevent etching of sensor wafer 5 during the manufacturing process of micromechanical device 100 . This is generally a layer including aluminum for this purpose.
[0034] FIG. 3 shows a second specific embodiment according to the present invention of a micromechanical device 100 . In this specific embodiment, the electrical terminal, which electrically conductively connects micromechanical device 100 to a circuit board, for example, is a solder ball 34 , which is situated on evaluation wafer 11 on the side facing away from intermediate wafer 1 . To connect solder ball 34 in an electrically conductive way to printed conductors 23 or the evaluation-oriented circuits, one or multiple through silicon vias (TSV) 32 , which are connected via a wiring level 33 to solder ball 34 , are provided in evaluation wafer 11 . This specific embodiment has the advantage that micromechanical device 100 may be situated directly on the circuit board in the sense of a bare die structure, the packaging of micromechanical device 100 , which is linked to additional costs, being able to be omitted. Through vias 32 are preferably filled or partially filled with metal and are insulated from the silicon of the evaluation wafer by an insulation layer.
[0035] FIGS. 4 through 7 show individual manufacturing steps for manufacturing a micromechanical device 100 according to the present invention. FIG. 4 shows a sensor wafer 5 and an intermediate wafer 1 , before they are connected to one another in a first connection step. Sensor wafer 5 includes a first sensor element 2 and a second sensor element 3 . In addition, sensor wafer 5 has a printed conductor 23 , which is electrically conductively connected to a sensor system, the sensor system including first sensor element 2 or third sensor element 3 . It is provided that the electrical signal from the sensor system is conducted via printed conductor 23 to an electrical contact, which is to electrically conductively connect intermediate wafer 1 to sensor wafer 5 . For this purpose, sensor wafer 5 preferably has a first aluminum (Al) layer 17 at the points provided for the electrical contact. In addition, sensor wafer 5 is preferably equipped with a first aluminum layer 17 at those points, at which a further, possibly solely mechanical connection is planned between intermediate wafer 1 and sensor wafer 5 , for example, for the hermetic closure of the intermediate wafer with the sensor wafer. Therefore, a first coating pattern is implemented on sensor wafer 5 on the side facing toward intermediate wafer 1 . Intermediate wafer 1 has a second coating pattern, which is situated congruently or approximately congruently to the first coating pattern on the side facing toward sensor wafer 5 and is preferably made of first germanium (Ge) layers 19 . In particular, it is possible that intermediate wafer 1 is structured, the structure corresponding to the second coating pattern and including ridges of the intermediate wafer which face toward sensor wafer 5 . In the specific embodiment shown, intermediate wafer 1 has further ridges in addition to the second coating pattern. In following FIGS. 5 through 7 , each of the features or components described in the preceding figure are supplemented with further components or further features. Therefore, in FIGS. 5 through 7 , the features or components of the micromechanical device which are already known from the preceding figure are not described in detail again. FIG. 5 shows how intermediate wafer 1 and evaluation wafer 5 are connected to one another via a first AlGe connection 4 after a first connection step, the connections being located at the points at which the first coating pattern is congruent with the second coating pattern. If the intermediate wafer has a structure at these points, it is referred to hereafter as a ridge of first type 14 . All further structures on the side of the intermediate wafer facing toward the sensor wafer are referred to hereafter as ridges of the second type and generally form stops 16 , which are preferably provided to prevent a spring fracture of the seismic mass in the event of an overload. A first cavity 120 and a second cavity 130 , which both have a first gas pressure, are produced by the first connection step.
[0036] FIG. 6 shows an evaluation wafer 11 and an intermediate wafer-sensor wafer stack 10 before a second connection step. Intermediate wafer-sensor wafer stack 10 includes intermediate wafer 1 and sensor wafer 5 after it (i.e., intermediate wafer-sensor wafer stack 10 ) has been structured. In general, an anisotropic etching method is provided for the structuring, which induces openings or interruptions in the intermediate wafer, whereby the intermediate wafer has individual isolated points, i.e., small rods/stamps, which are linked via AlGe connection 4 to sensor wafer 5 . In one preferred specific embodiment, the anisotropic etching method also etches into the sensor wafer, whereby printed conductors are exposed which are possibly situated in the sensor wafer. It is additionally provided according to the present invention that one of the openings or interruptions caused by the etching method, for example, forms a small access 7 . A second gas pressure in the second cavity will then generally no longer correspond to the first gas pressure in the first cavity, for which a small access is not provided.
[0037] Before the second connection step is completed, intermediate wafer 1 may be structured on its side facing toward evaluation wafer 11 , whereby recesses 20 result, for example. A sensor means could be situated in these recesses, for example.
[0038] To complete the second connection step, the intermediate wafer has a third coating pattern, on the side facing away from sensor wafer 5 , which is preferably made of a second germanium (Ge) layer 29 . A germanium layer 29 is to be located on each of the small rods of the intermediate wafer. The third coating pattern is congruent or approximately congruent with a fourth coating pattern applied to the evaluation wafer, the coating pattern being made of second aluminum (Al) layers. Evaluation wafer 11 additionally includes a bond pad 30 , via which the micromechanical device may preferably establish the electrical contact to a circuit board.
[0039] FIG. 7 shows a micromechanical device after the second connection step, intermediate wafer 1 and evaluation wafer 11 being connected to one another via a second AlGe connection 9 . The gas pressure in the second cavity generally differs from that in the first cavity, because the second cavity could assume the ambient gas pressure via the small access during the second connection step. In one alternative specific embodiment, the second cavity accommodates a second atmosphere (having a second type of gas or a second gas mixture) during the first connection step, which differs from a first atmosphere (having a first type of gas or a first gas mixture), which has been accommodated by the first cavity during the first connection step.
[0040] In addition, in the specific embodiment shown, micromechanical device 100 has a germanium etching 31 of the intermediate wafer, whereby a cavity is implemented above bond pad 30 . In this specific embodiment, it is possible to expose bond pads 30 without damage during a sawing process.
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A micromechanical device having a main plane of extension includes a sensor wafer, an evaluation wafer, and an intermediate wafer situated between the sensor wafer and the evaluation wafer, the evaluation wafer having at least one application-specific integrated circuit. The sensor wafer and/or the intermediate wafer includes a first sensor element and a second sensor element spatially separated from the first sensor element, the first and second sensor elements being respectively located in a first cavity and a second cavity each formed by the intermediate wafer and the sensor wafer, a first gas pressure in the first cavity differing from a second gas pressure in the second cavity, and the intermediate wafer having an opening at a point in a direction perpendicular to the main plane of extension.
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FIELD OF THE INVENTION AND RELATED ART STATEMENT
The present invention relates to a roller of a draft apparatus in a spinning machine.
A draft apparatus is provided with plural pairs of draft rollers such as back rollers, middle rollers and front rollers. The roller pairs rotate while holding a fiber bundle under pressure to thereby draft the fiber bundle at a predetermined draft ratio. These roller pairs are each composed of a bottom roller which is rotated positively by a motor and a top roller which is brought into pressure contact with the bottom roller and thereby rotated. Generally, the bottom rollers are constituted as a single shaft common to all spindles, while the top rollers are constituted as relatively short shafts which are independent at every two spindles. In order to ensure the gripping for a fiber bundle between bottom and top rollers, usually the bottom roller portion in contact with the fiber bundle is formed with a fine unevenness, while a rubber cot is fitted over the outer periphery of the top roller portion. More specifically, the portion (hereinafter referred to as the "draft portion") of the bottom roller which is contact with a fiber bundle is merely formed so that its outside diameter is the same as or slightly larger than that of the other portion. Where a plurality of shafts are interconnected to constitute a single bottom roller, the connections are sometimes made smaller in diameter than the draft portion. Even in such a case, however, the roller portions adjacent to the draft portion have about the same outside diameter as that of the draft portion, and in many cases there is formed a stepped portion at the boundary of the large and the small diameter portion of the bottom roller.
During operation of a draft apparatus, short fibers which constitute the above fiber bundle are sometimes separated from the fiber bundle and wind around the draft roller. Once this occurs, there arises unevenness in thickness or breakage of spun yarn, so in this case it is necessary to discontinue the spinning operation and remove the fibers wound onto the roller. If the fibers on the roller are cut with a cutter knife or the like, the peripheral surface of the roller may also be damaged by the knife, so the use of such knife or the like is not desirable. Since the top rollers are independent at every two spindles as previously noted, the fibers wound onto the top rollers are easily removed by being moved axially of the rollers, while the bottom rollers are constituted as a single shaft common to all spindles and the entirety is about the same in diameter, so the removal of the wound fibers is an extremely difficult work.
OBJECT AND SUMMARY OF THE INVENTION
It is an object of the present invention to provide a roller of a draft apparatus from which fibers wound onto the roller can be easily removed.
The draft roller of the present invention is characterized in that its portion in contact with a fiber bundle, i.e. the draft portion, is made relatively large in diameter, and the roller portions adjacent to the draft portion are tapered gradually away from the draft portion.
According to the draft roller of the present invention, when fibers are wound around the draft portion, the fibers are moved from the draft portion to the above tapered portions whereby looseness can be imparted to the fibers. If in this state a suitable cutter is inserted between the fibers and each tapered portion to cut the fibers, the wound fibers can be removed easily without damaging the peripheral surface of the roller.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a view showing a draft roller embodying the present invention and
FIG. 2 is a perspective view of a pneumatic type spinning machine.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
FIG. 2 illustrates a pneumatic type spinning machine, in which a fiber bundle or sliver S drawn out from a can 1 passes through a draft apparatus D which comprises back rollers 2, middle rollers 4 each having an apron 3 and front rollers 5. Thereafter, the sliver S is introduced into an air injection nozzle 6, then drawn out by delivery rollers 7 and passes through a slub catcher 8. Further, it is guided by a traverse guide 9 and wound onto a package P being rotated by means of a friction roller 10. The above draft rollers, namely, back rollers 2, middle rollers 4 and front rollers 5, are respectively constituted as pairs of top rollers 2a, 4a, 5a located above and bottom rollers 2b, 4b, 5b located below. The top and bottom rollers rotate while holding the sliver S under pressure to draft the sliver. The top rollers are independent at every two spindles and they are supported by a top roller support 11. The bottom rollers are constituted as a single shaft common to all spindles, which shaft is rotated positively by means of a motor (not shown). Actually, this shaft comprises rollers independent at every two spindles and interconnected in series by coupling. Further, a cylindrical rubber cot 12 having a uniform thickness is fitted over the top roller portion which is in contact with the sliver S. The sliver S can be gripped positively by the elasticity of the said rubber. The air injection nozzle 6 applies a compressed air stream to the sliver S leaving the front rollers 5 to thereby twist the sliver to obtain a spun yarn Y.
FIG. 1 illustrates the front bottom roller 5b and a structure for supporting the same.
The bottom rollers 5b, formed of a metal, are independent at every two spindles as previously noted and are interconnected by a later-described coupling. Each roller 5b comprises draft portions 15 formed on both sides of a central portion 14 having a uniform thickness, tapered portions 16 formed outside the draft portions, and connections 17 of a small diameter formed at still outside end portions. The draft portions 15 which are in pressure contact with the top roller 5a through the fiber bundle S have a diameter slightly larger than that of the central portion 14, and the connections 17 are of the smallest diameter. The tapered portions 16 are each in a conical shape which connects the outer periphery of the draft portion 15 and that of the connection 17 smoothly to prevent the formation of a clear difference in height between both portions. That is, the outside diameter of the tapered portion decreases gradually from the draft portion 15 toward the connection 17. The front roller 5b is provided in plural numbers, which are interconnected and fixed by means of a coupling 18 in an opposed state of the connections 17. Numeral 19 denotes a bottom roller supporting block fixed onto a base 20 of the spinning machine. The coupling 18 is housed in an axial bore 21 of the supporting block 19, and bearings 22 are provided between the connections 17 on both sides of the coupling 18 and the supporting block 19, whereby the bottom roller 5b is supported rotatably. Numeral 23 denotes a collar for preventing the entry of dust, etc. and numeral 24 denotes a bolt for fixing the supporting block 19. In FIG. 1, the coupling 18, etc. at the right end portion of the roller 5b are omitted.
The following description is now provided about the operation of the roller 5b.
During draft operation, when fibers wind around the right-hand draft portion 15 in FIG. 1, the operator moves the wound fibers toward the right-hand tapered portion 16 by means of a suitable jig. Since the tapered portion 16 is of a smaller diameter than the draft portion 15, the wound fibers f thus moved are loosened on the tapered portion 16. Then, a suitable cutter or jig 25 is inserted between the wound fibers f and the tapered portion 16 and pulled in the direction of arrow 26 to thereby cut and remove the fibers f.
Since the tapered portion 16 is of a smaller diameter than the draft portion 15, the foregoing wound fiber removing operation is facilitated. On the other hand, where the tapered portion 16 is not conical but cylindrical, that is, where the tapered portion 16 is in the form of a cylinder having approximately the same diameter as the connection 17, there is formed a large difference in height at the boundary of the tapered portion 16 and the draft portion 15 and consequently there arises the following problem. Such a roller is subjected to a quench hardening treatment in the manufacturing process for impartment of strength thereto. But since there is the above difference in height on the roller, the quench hardening becomes non-uniform at this stepped portion, thus resulting in formation of a weak point in strength. Such a difficulty in quench hardening treatment can be overcome by forming the tapered portion 16 conically to remove the above difference in height, whereby a roller having a sufficient strength can be obtained.
Although in FIG. 1 the tapered portions 16 are formed outside the draft portions 15, they may be formed in inside positions, namely, at the central portion 14. However, most preferred dynamically is the roller shape shown in FIG. 1 in which the connections 17 at both ends supported by the bearings 22 are made small in diameter, and from the connections 17 there are formed the large diameter draft portions 15 and central portion 14 through the conical tapered portions 16.
According to the roller of the present invention, the fibers wound around the draft portions can be removed easily and it is possible to maintain a sufficient strength.
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A draft roller in a spinning machine in which its portion in contact with a fiber bundle, i.e. the draft portion, is made relatively large in diameter, and the roller portion adjacent to the draft portion are tapered gradually away from the draft portion so that fibers wound around the draft portion are moved therefrom to the tapered portions and can be removed easily.
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CROSS REFERENCE TO RELATED APPLICATION
This is a continuation-in-part of my copending application Ser. No. 730,546, filed Oct. 7, 1976 and now abandoned.
BACKGROUND OF THE INVENTION
2-[(3,4-Dichlorophenoxy) methyl]-2-imidazoline and its pharmaceutically acceptable salts are known to have antidepressant and barbiturate antagonist activity (White, U.S. Pat. No. 3,449,355) and alcohol antagonist activity (Marshall U.S. Pat. No. 3,860,719). The compound is generically known as "fenmetozole." Fenmetozole and its salts have a favorable low toxicity. Fenmetozole hydrochloride has been administered to adult humans, both normal subjects and schizophrenic and/or depressed patients at dosages of 250 to 450 milligrams fenmetozole hydrochloride per day for 3-4 weeks. (Chien and Kaplan, Curr. Therap. Res. 11,471-474 (1969) and 13,350-352 (1971)) and has also been administered to normal adults at single dosages ranging from 25 to 250 milligrams with no ill effects reported other than a "tingling sensation" on the skin reported by some of the subjects, decreased heart rate and increased blood pressure at high dose level, Fink, Curr. Therap. Res. 18, 590-596 (October 1975).
Minimal Brain Dysfunction ("MBD") is a recognized neuropathological condition occurring in children, characterized by symptoms including hyperkinesis, chronic short attention span, distractibility, emotional lability and a characteristic electroencephalogram ("EEG"). Ethiology is unknown and diagnosis requires discrimination between MBD and similar behavioral symptons due to environmental factors (such as diet) and/or primary psychiatric disorder. EEG analysis is thus a significant factor in differential diagnosis. Over the last ten years, stimulant drugs have assumed a major role in the treatment of children with Minimal Brain Dysfunction. The synthetic sympathomimetic amines (especially methylphenidate) are known to be particularly useful. Recent advances in electrophysiology, utilizing specialized equipment and computerized measurement, permit the precise evaluation of various forms of brain dysfunction and abnormality. The practical application of these techniques permit: assessment of neuropathology, evaluation of drug effects, and assessment of sensory function and cognitive processes with a high degree of objectivity.
SUMMARY OF THE INVENTION
It has now been discovered that 2-[(3,4-dichlorophenoxy)methyl]-2-imidazoline (fenmetozole) and its pharmaceutically-acceptable salts are useful in alleviation of Minimal Brain Dysfunction in children. The invention thus concerns the internal administration to children suffering from Minimal Brain Dysfunction ("MBD") an amount of fenmetozole or a pharmaceutically-acceptable salt thereof sufficient to alleviate the Minimal Brain Dysfunction. In a preferred embodiment, the compound fenmetozole hydrochloride is administered orally to children between the ages of about 5 and 15 years and exhibiting symptoms of MBD, (diagnosed or diagnosable symptoms preferably including characteristic EEG changes) in an amount effective to reduce one or more of the MBD symptoms. Preferably, the amount is about 0.5 to 10 milligrams of fenmetozole hydrochloride per kilogram of body weight per day.
DETAILED DESCRIPTION
In the practice of the invention, fenmetozole or a specified salt is administered internally to a human child having MBD. The child under treatment is one of an age at which MBD is manifested, normally from about 5 or 6 to about 15 years of age. The child is also one suffering from MBD, that is, conditions such as hyperkinesis, learning disability, chronic short attention span. Diagnosis should include EEG analysis, and should be carefully conducted to differentiate between MBD and other conditions. Also, blood pressure determinations should be made and non-hypertensive children with MBD (normal blood pressure or hypotension) are preferred subjects to those having MBD with hypertension.
The compound can be administed orally or by injection or suppository, but oral administration is generally preferred. The exact dosage to be administered will vary somewhat from subject to subject depending on factors such as exact compound, dosage form and route of administration employed; age, size and weight of child; time and frequency of administration, etc. The dosage and regimen to be used in particular cases can be ascertained by conventional procedures, such as the use of EEG analysis to follow the effect of different dosages. In general, an effective dose will be from about 0.5 to about 10 milligrams of compound per kilogram of body weight per day, administered singly or, preferably in multiple divided dosages (e.g. two doses morning and noon. Preferably, the dosage administered either on a daily basis or at a given time (whether as the entire daily dose or a portion thereof) is also kept below an amount which produces serious, non-transitory increases in blood pressure. Preferred effective dosages are in the range of from about one to about five milligrams per kilogram per day with individual divided doses being between about 0.5 and about 3 mg/kg.
The following example is illustrative.
EXAMPLE 1
Fenmetozole hydrochloride was administered to children in the age range of 5 to 15 years, having diagnosed MBD. Fenmetozole hydrochloride was employed orally at a daily dosage rate of about 3 mg/kg/day using three divided dosages. (The compound was provided in 25 and 50 mg capsules, and the regimen adjusted to approximate 3 mg/kg daily for each child).
For comparison, methylphenidate (Ritalin® -- CIBA) was used at a recommended dosage rate of 0.6 mg/kg/day. EEG's were taken and recorded both pre-drug and post drug so that drug effect could be analyzed against the individual subjects' own pre-drug (untreated) EEG as a baseline. EEG analyses included both resting analyses (discrete wave band analyses, signal ratio, etc.) and evoked potential studies (visual and auditory evoked responses). Additionally, crossover studies were conducted in which a child was tested on administration of one drug for 4 days, then with the other drug for 4 days (after an intervening "wash out" period of three weeks without any drug, so that fenmetozole hydrochloride and methylphenidate could be compared in the same child. Thirteen subjects were tested. In each case methylphenidate was administered first so that any "carry over" drug effect still present after the "wash out" period would tend to bias the study against fenmetozole hydrochloride. The studies indicated that fenmetozole was at least as effective as methylphenidate in alleviating MBD, as indicated by EEG normalization in both the resting and evoked potential studies. In general, methylphenidate produced more pronounced improvement in resting analysis than in evoked potential, while fenmetozole produced marked improvement in evoked response and less effect on resting analysis. No significant effect on blood pressure was noted. Pulse rates were increased after methylphenidate treatment, but not after fenmetozole.
EXAMPLE 2
To assess drug abuse potential, fenmetozole hydrochloride was tested in comparison to methylphenidate to examine the ability of each compound to maintain a self-injection reponse in monkeys which had been trained to self-inject codeine. Differences in the self-injection reinforcement properties are indicative of a difference in the abuse potential of drugs. Woods and Tessel, Science, 185, 1067-9 (1974) and Tessel and Woods, Psychopharmacologia, 43, 239-244 (1975). Methylphenidate has been reported to maintain self-injection responses. Johansen and Schuster, J. Pharmacol. Exptl. Therap. 193; 676-688 (1975).
Three rhesus monkeys were prepared and trained to self-inject codeine (0.3 mg/kg/injection) in accordance with known procedures. Doses of fenmetozole hydrochloride (0.01 to 0.32 mg/kg/injection) and methylphenidate (0.003 to 0.32 mg/kg/injection) were alternated in each monkey and the responses compared to response produced with codeine and with normal saline. Methylphenidate at 0.003 mg/kg/injection produced response rates similar to those produced by saline (less than 0.05 response per second); 0.01 mg/kg/injection increased self-injection response rates and the maximal self-injection rate (comparable to the codeine rate) was found at 0.03 mg/kg/injection. Larger doses reduced the rate from its maximum of 2.0-2.5 responses/second to about 1.5 responses/second. Fenmetozole hydrochloride had a much lower effect than methylphenidate at all doses. The maximal response to fenmetozole was less than 0.5 response/second at 0.10 mg/kg/injection, and was less than two standard deviation units from the response to normal saline.
These results show that fenmetozole does not produce significant self-injection responses when compared to methylphenidate, indicating the fenmetozole lacks significant abuse potential. In other studies, fenmetozole has not been found to cause hallucinogenic side effects.
While some EEG studies in normal adults have indicated some similarities between fenmetozole and methylphenidate, the comparative effect of the two on MBD in children, and other studies indicate significant differences in the psychopharmacological effects of the two drugs.
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A method useful for alleviating minimal brain dysfunction in humans comprises internally administering to a human an effective amount of 2-[(3,4-dichlorophenoxy)methyl]-2-imidazoline or a pharmaceutically-acceptable salt thereof.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a method and composition for the topical treatment of diabetic neuropathy. More particularly, the present invention relates to a topical composition including a combination of ingredients that provide a surprising degree of effective relief from the symptoms of diabetic neuropathy and to a method for administering the topical composition to treat diabetic neuropathy.
[0003] 2. Description of the Prior Art
[0004] Diabetes mellitus is a common disease that is usually classified into insulin-dependent and non-insulin dependent types. Both types may be managed by diet, in combination with insulin in the first type and a variety of drugs in the second type. However, while the changes in blood glucose associated with diabetes can usually be managed reasonably satisfactorily by conscientious patients and doctors, this does not prevent long term damage to many tissues as a result of the disease. This damage may take many forms but the major types are damage to the eyes (retinopathy), nerves (neuropathy), kidneys (nephropathy) and cardiovascular system,
[0005] There are many approaches to reducing or preventing these forms of damage, which are collectively known as the long-term complications of diabetes. One approach is based on damage that results from over-production of the glucose metabolite, sorbitol, in the cells of the body, Glucose can be converted to sorbitol by the enzyme aldose reductase. High levels of sorbitol may be among the causes of diabetic complications such as diabetic neuropathy. As a result, a number of pharmaceutical companies have been developing aldose reductase inhibitors for the purpose of reducing diabetic neuropathy.
[0006] It has been established that a wide variety of flavanoids are effective inhibitors of aldose reductase, including such flavanoids as quercetin, quercetin and myrecetrin. However, U.S. Pat. No. 4,232,040 discloses that despite the fact that these flavanoids have been shown in in vitro studies to be among the most potent flavanoids for aldose reductase inhibition, a need exists for aldose reductase inhibitors that can be more effectively used and in lower doses than the prior art compounds, including these flavanoids.
[0007] In fact, numerous patents are devoted to goal of developing improved aldose reductase inhibitors. Among these patents are U.S. Pat. Nos. 6,069,168; 5,011,840; 4,210,667; 4,147,795; 5,866,578; and 5,561,110. Numerous other patents also exist which relate to aldose reductase inhibitors.
[0008] Another approach to the treatment of neuropathy is disclosed in U.S. Pat. No. 5,840,736 (Zelle et al.). In this method, pharmaceutical compositions for stimulating the growth of neurites in nerve cells comprising a neurotrophic amount of a compound and a nerve growth factor. These compositions may be administered in a number of ways including orally and topically.
[0009] Still another approach to the treatment of neuropathy is disclosed in U.S. Pat. No. 5,550,249 (Della Ville et al.). In this approach, compositions suitable for treatment of vitamin H deficiencies are administered for the treatment of neuropathy. This patent relates to biotin salts with alkanolamines. The compositions may be administered orally, parenterally or topically.
[0010] U.S. Pat. No. 5,665,360 (Mann) relates to the treatment of peripheral neuropathies associated with diabetes mellitus by periodic topical application of a composition containing capsicum oleoresin as the active ingredient. When applied to the skin of the affected area, pain and burning associated with the neuropathy are said to be reduced. However, capsicum oleoresin has been shown to kill nerve endings in some cases and thus this composition suffers from this disadvantage.
[0011] U.S. Pat. No. 5,981,594 (Okamoto et al.) relates to a method of treatment of diabetic neuropathy using combined administration of a formulation including as an active ingredient, a prostaglandin I derivative with an anti-diabetic agent in order to improve nerve conduction velocities. Suitable anti-diabetic agents include oral hypoglycemic agents and insulin.
[0012] The Okamoto patent also contains a detailed discussion of the various types of neuropathy that may be associated with diabetes. According to this patent, nerve conduction velocity (NCV) is the most widely used method of objectively evaluating the severity of diabetic neuropathy. This patent also mentions that current methods of treating diabetic neuropathy such as dietetic therapy, administration of insulin, administration of aldose reductase inhibitors or aminoguaninidine to improve abnormal glucose metabolism, administration of troglitazone or agents for the improvement of blood flow have been tested but found to be insufficient when a single drug was used. Also, according to this patent, methods of treatment by combined use of different therapeutic agents which have different functions had yet to be established. The patent concludes that combined drug therapies for diabetic neuropathy, aiming at recovering once reduced nerve conduction velocity, have not yet been confirmed.
[0013] There remains a need in the art for an effective treatment for diabetic neuropathy that does not suffer from the disadvantage that it causes severe side effects, as do many aldose reductase inhibitors, for example.
[0014] Accordingly, it is the primary object of the present invention to provide a topical composition that is effective for the treatment of diabetic neuropathy.
[0015] It is another object of the present invention to provide a topical composition for the treatment of diabetic neuropathy which does not cause serve side effects in the patients treated with the composition.
[0016] These and other objects of the present invention will be apparent from the summary and detailed descriptions of the invention which follow.
SUMMARY OF THE INVENTION
[0017] In a first aspect, the present invention relates to a topical composition for the treatment of diabetic neuropathy. The composition comprises a cold compounded mixture of a compound that promotes synthesis of nerve growth factor, an aldose reductase inhibitor and an antioxidant formulated in a pharmaceutically acceptable carrier. It has been found that this combination of active agents provides significant, effective relief of the symptoms of diabetic neuropathy, as well as at least partial recovery of lost neurological function in some cases. In view of the consensus in the art that effective combinations of various active agents have not been demonstrated to be effective for the treatment of diabetic neuropathy, the present invention provides a surprising and unexpected effect. In addition, the topical compositions of the present invention, when used in effective amounts to treat diabetic neuropathy, do not exhibit the severe side effects of many prior art compositions proposed for treatment of this ailment,
[0018] In a second aspect, the present invention relates to a method for the topical administration of a composition in accordance with the present invention for the treatment of diabetic neuropathy. In the method, an effective amount of the composition of the invention is topically administered to the areas of the body that have been adversely affected by the diabetic neuropathy on a regular basis over a period of time sufficient to provide the beneficial effects of relief from the symptoms and at least some recovery of the damaged nerve tissues.
[0019] In a third aspect, the present invention relates to a pharmaceutically acceptable carrier for topical compositions that provides excellent dispersions and/or solutions of active ingredients and good penetration through the skin to the areas to be treated. The carrier for topical compositions may also include one or more materials that provide beneficial properties to the skin since many sufferers from diabetic neuropathy develop skin problems such as ulcers, lesions or cell damage.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0020] In a first aspect, the present invention relates to a topical composition for the treatment of diabetic neuropathy. The composition includes a compound that promotes synthesis of nerve growth factor, an aldose reductase inhibitor and an antioxidant formulated in a pharmaceutically acceptable carrier for a topical composition.
[0021] The compound that promotes synthesis of nerve growth factor may be selected from suitable compounds that have been shown to have this activity. Suitable compounds that promote synthesis of nerve growth factor are those that do not induce significant, adverse side effects when topically applied to a patient in amounts that promote synthesis of nerve growth factor, and which do not react with one or more of the ingredients of the topical composition resulting in a substantial loss of activity of one or more active ingredients. Preferred compounds for promoting synthesis of nerve growth factor are those that occur naturally in the human body and/or materials obtained from plants or animal which may be ingested or topically applied by humans without significant, adverse side effects in the amounts used or derivatives thereof
[0022] Exemplary compounds that promote synthesis of nerve growth factor are vitamin D 3 , vitamin D 3 derivatives such as 1(S), 3(R)-dihydroxy-20(R)-(1-ethoxy-5-ethyl-5-hydroxy-2-heptyn-1-yl)-9, 10-seco-pregna-5(Z), 7(E), 10 (19)-triene. The preferred nerve growth factor used in the topical composition is vitamin D 3 . Also, pharmaceutically acceptable salts of the compounds that promote synthesis of nerve growth factor may be employed.
[0023] The compound that promotes synthesis of nerve growth factor is used in an amount effective to promote the synthesis of nerve growth factor of about 10,000 to about 3 million IU. per kg of the composition. More preferably, the compound that promotes synthesis of nerve growth factor is employed in an amount of about 50,000 to about 2 million IU per kg of the composition, and most preferably an amount of 100,000 to about 1 million IU is used per kg of the composition.
[0024] The preferred compounds that induce synthesis of nerve growth factor may, in addition to this activity, also function to prevent neurotrophic deficits. This additional effect of the preferred compounds may also contribute to the overall beneficial effect of the topical composition of the present invention.
[0025] In order to formulate the compound that promotes synthesis of nerve growth factor in the topical composition of the present invention, it may be necessary to use a dispersant. Suitable dispersant materials are known to persons skilled in the art. A particularly suitable dispersant for the compounds that promote synthesis of nerve growth factor is corn oil. Corn oil also has the advantage that it is a natural product. The amount of corn oil used is an amount sufficient to disperse the compound that promotes synthesis of nerve growth factor.
[0026] The second active ingredient of the topical composition of the present invention is an aldose reductase inhibitor. Numerous suitable aldose reductase inhibitors are known to persons skilled in the art. Again, suitable aldose reductase inhibitors are those that do not induce significant, adverse side effects when topically applied to a patient in an amount effective for aldose reductase inhibition, and which do not react with one or more of the ingredients of the topical composition resulting in a substantial loss of activity of one or more active ingredients of the composition. Preferred aldose reductase inhibitors are those that occur naturally in the human body and/or materials obtained from plants or animal which may be ingested or topically applied by humans without significant, adverse side effects in the amounts used or derivatives thereof
[0027] As mentioned above, numerous aldose reductase inhibitors are known to persons skilled in the art. However, significant adverse side effects are associated with the use of many aldose reductase inhibitors in humans. Thus, it is important to select one or more aldose reductase inhibitors for use in the topical composition of the present invention based on minimizing the risk associated with use of the aldose reductase inhibitor taking into account the amount of that particular inhibitor that must be employed to achieve the desired level of aldose reductase inhibition. Different aldose reductase inhibitors exhibit different levels of inhibition. With this in mind, the preferred aldose reductase inhibitors for use in the topical compositions of the present invention are flavonoids and flavonoid derivatives. Exemplary aldose reductase inhibitors include (−)-epigallocatechin; (−)-epigallocatechin-gallate; 1,2,3,6-tetra-o-gallyol-β-d-glucose; 2′o-acetylacetoside; 3,3′,4 -tri-o-methyl-ellagic acid; 6,3′,4′-trihydroxy-5,7,8-trimethoxyflavone; 6-hydroxy-luteolin; 6-hydroxykaempferol-3,6-dimethyl ether; 7-o-acetyl-8-epi-loganic acid; acacetin; acetoside; acetyl trisulfate quercetin; amentoflavone; apiin; astragalin; avicularin; axillarin; baicalein; brazilin; brevifolin carboxylic acid; caryophyllene; chrysin-5,7-dihydroxyflavone; chrysoeriol; chrysosplenol; chrysosplenoside-a; chrysosplenoside-d; cosmosiin; δ-cadinene; dimethylmussaenoside; diacerylcirsimaritin; diosmetin; dosmetin; ellagic acid; ebinin; ethyl brevifolin carboxylate; flavocannibiside; flavosativaside; genistein; gossypetin-8-glucoside; haematoxylin; hispiduloside; hyperin; indole; iridine; isoliquiritigenin; isoliquiritin; isoquercitrin; jionoside; juglanin; kaempferol-3-rhamnoside; kaempferol-3-neohesperidoside; kolaviron; licuraside; linariin; linarin; lonicerin; luteolin; luetolin-7-glucoside; luteolin-7-glucoside; luetolin-7-glucoronide; macrocarpal-a; macrocarpal-b; macrocarpal-d; macrocarpal-g; maniflavone; methy scutellarein, naringenin; naringin; nelumboside; nepetin; nepetrin; nerolidol; oxyayanin-a; pectolinarigenin; pectolinarin; quercetagetin; quercetin; quercimertrin; quercitrin; quercitryl-2″ acetate; reynoutrin; rhamnetin; rhoifolin; rutin; soutellarein; sideritoflavone; sophoricoside; sorbarin; spiraeoside; trifolin; vitexin; and wogonin, The most preferred flavonoid and/or flavonoid derivative aldose reductase inhibitors are quercetin, quercetrin, myricetin, kaempferol and myrecetrin since these compounds exhibit a high level of aldose reductase inhibition in combination with a relatively low toxicity. Also, pharmaceutically acceptable salts of these aldose reductase inhibitors may be employed.
[0028] The flavonoids and flavonoid derivatives are also preferred since some of these compounds may provide additional beneficial effects in the composition of the present invention. For example, quercetin may act as a chelator for transition metals that some studies have linked to certain symptoms of diabetic neuropathy. Flavonoids may also have some anti-inflammatory activity and/or may help stabilize cell membranes, both of which activities may be beneficial in the treatment of diabetic neuropathy.
[0029] The aldose reductase inhibitor is used in an amount of about 2 to about 40 grams per kg of the composition. More preferably, the aldose reductase inhibitor is employed in an amount of about 5 to about 30 grams and most preferably an amount of 8 to about 20 grams per kg of the composition.
[0030] Another active ingredient in the composition of the present invention is the antioxidant. The antioxidant may be a single compound or a mixture of two or more compounds. Also, the antioxidant may include one or more compounds that provide additional beneficial effects beyond the antioxidant activity, such as aldose reductase inhibition,
[0031] Compounds which may be used as antioxidants are those which exhibit antioxidant activity when administered topically without causing any severe adverse side affect when used in an amount effective to provide sufficient antioxidant activity, and which do not react with one or more of the ingredients of the topical composition resulting in a substantial loss of activity of one or more active ingredients. Preferred antioxidants are those that occur naturally in the human body and/or materials obtained from plants or animal which may be ingested or topically applied by humans without significant, adverse side effects in the amounts used or derivatives thereof
[0032] More preferred antioxidants are selected from ascorbyl palmitate, ascorbic acid (vitamin C), vitamin A, vitamin E acetate, α-lipoic acid, especially DL-α-lipoic acid, coenzyme Q10, glutathione, catechin, glangin, rutin, luteolin, morin, fisetin, silymerin, apigenin, gingkolides, hesperitin, cyanidin, citrin and derivatives thereof which exhibit antioxidant activity. Even more preferably, mixtures of two or more antioxidants are employed in the composition of the present invention. Particularly preferred antioxidant mixtures are ascorbyl palmitate with one or both of vitamin A and vitamin E acetate. The antioxidants may also be used in the form of their pharmaceutically acceptable salts and this may be preferred in some cases to increase solubility or dispersability, to reduce adverse side effects, etc.
[0033] The antioxidant is used in an amount of about 1 to about 50 grams per kg of the composition. More preferably, the antioxidant is employed in an amount of about 2 to about 30 grams, and most preferably an amount of about 5 to about 20 grams per kg of the composition.
[0034] The antioxidants used in the composition of the present invention are preferably selected not only for their antioxidant activity, but also based on other beneficial effects that particular compounds may provide. For example, ascorbyl palmitate not only has antioxidant activity, but also may act as an aldose reductase inhibitor and may help prevent degradation of nitric oxide (NO) and thus is a particularly preferred antioxidant for the present invention. Similarly, vitamin E may also help prevent degradation of nitric oxide and is thus a preferred antioxidant. Vitamin A is a fat-soluble material and thus is preferred for use due to this additional beneficial property. However, due to its solubility characteristics, vitamin A may need to be formulated in a suitable dispersant such as corn oil in much the same manner as vitamin D 3 as described above,
[0035] Suitable additional beneficial properties for compounds useful in the compositions of the present invention include absorbability when applied topically, aldose reductase inhibition, antioxidant properties, free radical scavenging, transition metal chelation, nitric oxide stabilization, and anti-inflamatory activity.
[0036] The compositions in accordance with the present invention may provide one or more of the following beneficial effects to a patient when topically applied in effective amounts; relief of pain, burning, tingling, electrical sensations and/or hyperalgesia, increased microcirculation, nitric oxide stabilization, promotes healing of skin ulcers and lesions, protein kinase C inhibition, decreased oxidative stress, anti-inflammation, protection against radiation damage, particularly ultraviolet radiation, blockage of the formation of leukotrienes, stabilization of cell membranes, and promotion of the synthesis of nerve growth factor.
[0037] The method of the present invention involves the topical application of a composition of the present invention to areas of the skin in the vicinity of tissue that suffers from diabetic neuropathy. In particular, the present invention is useful on the patients' extremities such as the fingers, toes, hands and feet where diabetic neuropathy is often the most pervasive.
[0038] In the method, a suitable amount of the composition of the invention is applied one to six times daily as needed to relieve pain and other symptoms of the diabetic neuropathy. Preferably, the composition is applied two to four times daily, as needed for pain. A sufficient amount should be applied to cover the area afflicted with the diabetic neuropathy with a thin layer of the composition and the composition should be rubbed into the skin until little or no residue remains on the skin. Treatment begins initially to treat acute symptoms but may be continued indefinitely to relieve pain, prevent symptoms of diabetic neuropathy from returning and possibly restore some nerve and/or skin function.
[0039] The method of the present invention may provide one or more of the beneficial effects described above for the compositions of the invention. In addition, the method of the present invention may provide some additional beneficial effects due to one or more of the ingredients contained in the pharmaceutically acceptable carrier as described in more detail below,
[0040] The pharmaceutically acceptable carrier of the present invention is suitable for use as a carrier for topical compositions wherein the active ingredients are dissolved, dispersed and/or suspended in the composition. The carrier of the present invention contains at least a hydrophilic ointment base, panthenol or a panthenol derivative and a dispersant if needed to disperse one or more insoluble or partially insoluble active ingredients in the carrier.
[0041] Suitable hydrophilic ointment bases are known to persons skilled in the art. Exemplary hydrophilic ointment bases suitable for use in the present invention are non-U.S.P. hydrophilic ointment bases such as those made by Fougera, Inc. Sufficient hydrophilic ointment base is employed to act as a Garrier for the active ingredients of the composition. Typically the hydrophilic ointment base will make up more than about 80% of the total composition and more preferably about 80-90% of the composition is the hydrophilic ointment base. The hydrophilic ointment base functions as a carrier and enhances penetration into the skin.
[0042] The panthenol or panthenol derivatives useful in the present invention include at least D-panthenol, DL-panthenol and mixtures hereof This component of the carrier has skin moisturizing properties and acts as a quick, deep penetrating component of the carrier that helps deliver the active ingredients through the skin to the area to be treated and imparts a healing effect to damaged tissue. The amount of panthenol or panthenol derivative to be employed is from about 0.25 to about 10 weight percent, more preferably from about 0.5 to about 5 weight percent and most preferably from about 1 to about 2 weight percent, based on the total weight of the composition.
[0043] The carrier of the present invention may also include additional ingredients such as other carriers, moisturizers, humectants, emollients dispersants, radiation blocking compounds, particularly UV-blockers, as well as other suitable materials that do not have a significant adverse effect on the activity of the topical composition. Preferred additional ingredients for inclusion in the carrier are sodium acid phosphate moisturizer, witch hazel extract carrier, glycerine humectant, apricot kernal oil emollient, and corn oil dispersant.
[0044] Other materials which may optionally be included in the topical compositions of the present invention include inositol, other B-complex vitamins, and anti-inflammatory agents. The composition of the present invention may also be employed to facilitate wound healing, for the treatment of skin cancer and/or one or more symptoms thereof or as a composition for protecting skin from the harmful effects of radiation such as radiation breakdown.
[0045] The composition of the present invention is made by cold compounding. This is an important feature of the invention since one or more of the compounds employed in the topical composition are sensitive to heat or other types of energy and thus the activity of the composition may be detrimentally affected as a result of the formulation of the compositions in other manners. Thus, the ingredients of the topical composition the present invention are merely mixed together, without heating using a sufficient amount of the carrier to provide a substantially homogeneous cream or ointment. It may be necessary to dissolve, disperse or suspend one or more of the ingredients prior to cold compounding in order to ensure substantially homogeneous distribution of the active ingredients in the composition.
[0046] A preferred composition of the invention can be made using the following ingredients, all based on use of one pound of hydrophilic ointment base. 25-35 cc of a 50% aqueous solution of sodium acid phosphate moisturizing agent, 5-10 cc of D- or DL-panthenol, 5-10 cc of glycerine, 1-3 cc of apricot kernal oil, 3-5 cc of a dispersion of vitamins A and D 3 in a corn oil base, 10-20 cc of witch hazel extract, 0.5-2 cc of vitamin E acetate, 2-4 grams of ascorbyl palpitate and 4-8 grams of quercetin powder. Optionally, one or more of the glycerin, witch hazel extract, vitamins A and E and/or the ascorbyl palmitate can be reduced or eliminate from a particular composition, if desirable or larger amounts of one type of component, i.e. antioxidant, can be employed while reducing the amount of another component of the same type or having a similar type of activity,
[0047] The invention will now be further illustrated by the following example.
EXAMPLE 1
[0048] A topical composition including a mixture of an hydrophilic ointment base, sodium acid phosphate moisturizing agent, a witch hazel extract carrier, glycerine, apricot kernal oil and DL-panthenol as the pharmaceutically acceptable carrier and vitamins A and D 3 , ascorbyl palmitate, quercetin and vitamin E acetate was prepared by cold compounding. The formulation of the composition is given in Table 1,
[0049] The composition was prepared by first placing the hydrophilic ointment base in a stainless steel bowl and mixing briskly until the ointment becomes creamy. Then, the sodium acid phosphate, panthenol, ascorbyl palmitate, glycerine, apricot kernal oil, vitamins A and D 3 , witch hazel extract, vitamin E acetate and quercetin are added in that order. After each ingredient is added, mixing is continued until all traces of dry ingredients have disappeared and a substantially homogeneous mixture is obtained. The final color should be a consistent yellow and the cream should have the consistency of cake frosting. The mixture is then placed in a sterile container. All containers which contact the composition during mixing must also be sterilized with, for example, zephiran choride or a chlorox solution such as betadine.
[0050] This composition was topically administered, under the supervision of a physician, to several patients diagnosed with the most difficult cases of diabetic peripheral neuropathy. The topical composition was applied twice daily in the morning and afternoon, except that patients were permitted to apply the composition up to six times daily, as needed for pain relief over a period of a few days. All of the eight patients treated experienced immediate positive results that lasted up to a day or two after treatment was discontinued. The effects noted by the patients included the relief of burning pain, tingling, healing of damaged skin, and reversal of skin discoloration due to impaired circulation.
TABLE 1 Ingredient Amount Employed Hydrophilic ointment base 1 pound 50% aqueous solution of Sodium acid phosphate 25 cc DL-panthenol 5 cc Glycerine 5 cc Apricot kernal oil 3 cc Witch hazel extract 12 cc Vitamin E acetate 1 cc Ascorbyl Palmitate 2 grams Quercetin powder 4 grams
[0051] The foregoing detailed description of the invention and examples are not intended to limit the scope of the invention in any way and should not be construed as limiting the scope of the invention. The scope of the invention is to be determined from the claims appended hereto.
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A method and composition for the treatment of diabetic neuropathy is disclosed. The composition comprises a cold compounded mixture of a compound that promotes synthesis of nerve growth factor, an aldose reductase inhibitor and an antioxidant formulated in a pharmaceutically acceptable carrier. It has been found that this combination of active agents provides significant, effective relief of the symptoms of diabetic neuropathy, as well as at least partial recovery of lost neurological function in some cases. In view of the consensus in the art that effective combinations of various active agents have not been demonstrated to be effective for the treatment of diabetic neuropathy, the present invention provides a surprising and unexpected effect. In addition, the topical compositions of the present invention, when used in effective amounts to treat diabetic neuropathy, do not exhibit the severe side effects of many prior art compositions proposed for treatment of this ailment,
In a second aspect, a method for the topical administration of a composition in accordance with the present invention for the treatment of diabetic neuropathy is disclosed. In the method, an effective amount of the composition of the invention is topically administered to the areas of the body that have been adversely affected by the diabetic neuropathy on a regular basis over a period of time sufficient to provide the beneficial effects of relief from the symptoms and at least some recover of the damaged nerve tissues.
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BACKGROUND OF THE INVENTION
Portable compact disc players and/or other media playing devices, pocket computers, dedicated game consoles and wearable computers are very convenient and useful electronic devices to have for the convenience of enjoying a diverse universe of entertainment and information wherever and whenever the user wants to do so; However, We have found that the great majority of O.E.M. have neglected to include with the aforementioned devices, a convenient and safe way to carry them.
The method we have devised allows the user to carry the portable electronic information and/or entertainment rendering devices in a safe, convenient and reliable way. This method is safe for both the user and the device. The user does not have to become entangled with any hanging straps, ropes, strings, wires or too many hooks, . . . , etc. The portable information and/or entertainment rendering device is kept safe from falling to the ground and being damaged or totally destroyed. We have tested this carrier in several environments to make sure that the assertions we make, herein, are true.
The convenience of the carrier refers to its seamlessness, ease and intuitive utilization. The user will attach the carrier to the portable electronic information and/or entertainment rendering device and then clip it to himself/herself around the waistband, shirt pocket, pants pockets, blouse or shirt collar, back of the blouse or shirt collar, . . . , wherever there is a contour to hook up with.
The reliability of the carrier comes from the geometrical structure of it and the type of materials we used to manufacture it. The materials we used allow for maximum flexibility, elasticity and strength. The carrier can be attached and detached, respectively, on and off the portable electronic information and/or entertainment rendering devices.
We have already created a working prototype; it can be attached and detached at will to and from several models of portable compact disc players we have tested, from a particular manufacturer. We have tested its reliability by going to gymnasiums, running in tracks, going shopping, . . . , etc. So far, we have not had an accidental detachment event, yet.
BRIEF SUMMARY OF THE INVENTION
In summary, the device is an attacheable and detacheable carrier for portable electronic information and/or entertainment rendering devices without a built-in attachment clip (see definitions below).
Which device the carrier will mate with is determined at the time of manufacture; depending on the particular device, model and manufacturer, a small modification on the upper and lower portions of the carrier and decreasing/increasing its longitudinal length will make it engage the particular portable electronic information and/or entertainment rendering device.
We consider the following electronic devices and any combination thereof, to be portable electronic information and/or entertainment rendering devices:
Definitions:
1. portable compact disc players with/without (digital/analog) radio receiver.
2. portable electronic media rendering devices (digital video/digital audio regardless of format).
3. portable digital video disc players with/without wearable display and/or with/without terrestrial/satellite (digital/analog) television receiver.
4. portable (digital/analog) terrestrial/satellite television receiver with/without wearable display.
5. portable (digital/analog) satellite radio receiver.
6. portable (digital/analog) terrestrial radio receiver.
7. portable (digital/analog) terrestrial radio transceiver.
8. portable dedicated electronic game consoles.
9. pocket computers.
10. wearable computers.
Drawing Point of View Descriptive Statement:
THE VIEWS: (BRIEF DESCRIPTION)
a. FIG. 1 : REAR
b. FIG. 2 : LATERAL (RIGHT and LEFT, SYMMETRICAL)
c. FIG. 3 : FRONT
d. FIG. 4 : REAR (with parts named)
e. FIG. 5 : LATERAL (RIGHT and LEFT, SYMMETRICAL with parts named)
f. FIG. 6 : FRONT (with parts named)
g. FIG. 7 : ENGAGEMENT (LATERAL PERSPECTIVE)
DESCRIPTIVE GEOMETRY: (BRIEF DESCRIPTION)
Axes definitions and reference points are as follows:
1. The TOP-BOTTOM axis is denoted and spanned by the upper case symbol T (reference point for TOP) and upper case letter B (reference point for BOTTOM).
2. The FRONT-REAR axis is denoted and spanned by the upper case symbol F (reference point for FRONT) and upper case symbol R (reference point for REAR).
3. The SIDE-SIDE axis is denoted and spanned by the upper case symbol S (reference point for SIDE 1 ) and upper case symbol S′ (reference point for SIDE 2 ).
In FIG. 1 and FIG. 4 , the carrier prototype for compact disc players is shown from a rear perspective. The most important parts are shown, respectively. The upper case letter T indicates the top of the carrier and the lower case letter B indicates the bottom of the carrier.
In FIG. 2 and FIG. 5 , the compact disc player carrier prototype is shown from a lateral approach. The carrier is symmetrical alongside its TOP-BOTTOM axis, hence only one of the two possible lateral views is shown.
In FIG. 3 and FIG. 6 , the carrier prototype for portable compact disc players is shown from a frontal approach. The carrier prototype for portable compact disc players has no symmetry alongside its FRONT-REAR or SIDE-SIDE axis.
In FIG. 7 , the carrier prototype for portable compact disc players is shown engaging an actual portable compact disc player. It can be noted, that the carrier engages the compact disc player in an unobstrussive manner and allows the physical media to be placed into and removed from the portable compact disc player (an information and/or entertainment rendering device).
DETAILED DESCRIPTION OF THE INVENTION
As it applies to all information contained herein, we are defining as portable electronic information and/or entertainment rendering devices the following:
1. portable compact disc players with or without terrestrial/satellite (digital/analog) radio receiver. 2. portable electronic media rendering devices (digital video/digital audio regardless of format). 3. portable digital video disc players with/without wearable display and/or with/without terrestrial/satellite (digital/analog) television receiver. 4. portable (digital/analog) terrestrial/satellite television receiver with/without wearable display. 5. portable (digital/analog) satellite radio receiver. 6. portable (digital/analog) terrestrial radio receiver. 7. portable (digital/analog) terrestrial radio transceiver. 8. portable dedicated electronic game consoles. 9. pocket computers 10. wearable computers
Drawings alpha-numeric parts list and descriptions as applicable to FIGS. 4 , 5 and 6 is as follows: device interface body ( 1 ), user engagement hook body ( 2 ), hook base swiveling fulcrum ( 3 ), user engagement hook body base ( 4 ), user engagement hook body spring ( 5 ), user engagement hook body fulcrum ( 6 ), not assigned ( 7 ), ( 8 ), ( 9 ); tension release tab ( 10 ), set of upper primary device engagement hooks ( 11 ), set of upper secondary device engagement hooks ( 12 ), set of upper device engagement arms ( 13 ), device friction rubber retainer ( 14 ), set of lower device engagement arms ( 15 ), set of lower device engagement hooks ( 16 ), not assigned ( 17 ), ( 18 ), ( 19 ); user operation friction surfaces ( 20 ), user engagement hook friction surfaces ( 21 ), upper device engagement arms curvature angle (C 1 ), upper device engagement arms curvature length (L 1 ), lower device engagement arms curvature angle (C 2 ), lower device engagement arms curvature length (L 2 ), the upper lateral angle (C 3 ) between ( 13 ) and ( 15 ), the upper lateral curvature length (L 3 ) between ( 13 ) and ( 15 ), the lower lateral angle (C 4 ) between ( 13 ) and ( 15 ), the lower curvature length (L 4 ) between ( 13 ) and ( 15 ), the angle (C 5 ) between ( 15 ), the curvature length (L 5 ) between ( 15 ), the gangle (C 6 ) between ( 13 ), the curvature length (L 6 ) between ( 13 ), hook body base swiveling fulcrum axis of rotation (A) and user engagement hook body fulcrum axis of rotation (B).
The carrier device is designed to be attached or detached at will and with ease on/off the portable electronic information and/or entertainment rendering devices; This in turn allows the user to carry and use the aforementioned devices attached to his/her belt, pant pockets, shirt pockets, T-shirt neck, pant or skirt waistline, purse pocket, carrying case pocket, etc. With very small modifications at the upper and lower portions of the carrier and its longitudinal length, it can be mated to many different types of portable electronic information and/or entertainment rendering devices. The initial prototype, was meant to mate with a specific compact disc player model from one particular manufacturer; soon we realized that we could use the carrier with other compact disc players from that same manufacturer. In addition, we realized that by making slight changes on the upper and lower engaging points of the carrier, we can mate the carrier to other compact disc players and other media playing devices from the same and other manufacturers. Furthermore, we realized that the carrier could be modified easily to mate to portable electronic dedicated game consoles, pocket computers and wearable computers.
In this manner, the user of the portable electronic information and/or entertainment rendering device, can enjoy the use of the device without the hassle of hanging strings and/or straps. Furthermore, the worry of accidental damage to the portable electronic information and/or entertainment rendering device due to an accidental fall is greatly minimized regardless of the activity in which the user is involved. The carrier device is very unobstrussive. Furthermore, we have personally tested the carrier device on a physical fitness center setting. We have done the following while wearing the carrier device on our fitness pants carrying number # 1 (see “Tested Compact Disc Players and Other Media Playing Devices”).
What is new and different with this portable electronic information and/or entertainment rendering device carrier is that it allows the user to change the media without unbuttoning or unstrapping anything. Furthermore, the user is able to carry the portable electronic information and/or entertainment rendering device anywhere on his/her body where there is a closed loop-like topology. Furthermore, is light weight, compact and unobstrussive. and/or entertainment rendering devices is not by engolfing them in a protective “pouch”, but by engaging the built-in edges, crevices and contours (when available) on the portable electronic information and/or entertainment rendering devices. The “carrier” uses small hooks and frictional surface forces to attach itself to the portable electronic information and/or entertainment rendering devices, thus preventing accidental detachment and slippage.
Mode of Engagement:
Portable Electronic Information and/or Entertainment Rendering Device Type:
Portable Compact Disc Players
Pick up the carrier by its back on one hand and then pick up the compact disc player and/or other media playing device with the other hand. Bring the back of the compact disc player and/or other media playing device in front of the carrier. Now, engage the bottom hooks of the carrier with the lower edge(s) and/or contour(s) of the compact disc player and/or other media playing device. When this engagement has been achieved, Now, proceed to engage the top of the compact disc player and/or other media playing device with the top of the carrier; now, proceed to push the compact disc player and/or other media device upper edges and/or contour(s) towards the upper double row of hooks; when the double “clicking” sound is heard, full engagement has been achieved. These procedures were tested with the working prototype as it applies to the compact disc players and/other media playing devices as described in:
“Tested Compact Disc Players and Other Media Playing Devices”.
Tested Activities and Environments:
Indoors:
Thread Mill, Weight Lifting, Frontal Crunches, Lateral Crunches, Circuit Running, Office work, Warehouse work, Auto repair shop, Light manufacturing, Sitting, Walking.
Outdoors:
Jogging, Running, Bicycling, Fishing(*), Walking, Hiking, Skiing, Roller-Blading, Skating, Motorbicycle racing (Track/Field), Mountain climbing, Surfing(*), Boating(*), Water Skiing(*), Skateboarding.
(*) The compact disc player and/or other media devices must be protected against water damage.
Tested Compact Disc Players and Other Media Playing Devices:
1. SONY(®) “Car Ready Walkman” with G-Protection
[Model Name: CD WALKMAN Model Number: D-EJ368CK]
Manufacturer Address:
Sony Corporation
6-7-35 Kitashinagawa; Shinagawa-ku, Tokyo, 141-0001 Japan ZHT
[Manufacturer locale: SONY Corp., China]
[Serial Number: 3-250-565-01]
2. SONY(®) “Sportsman Walkman” with G-Protection
[Model Name: CD WALKMAN Model Number: unknown]
Manufacturer Address:
Sony Corporation
6-7-35 Kitashinagawa; Shinagawa-ku, Tokyo, 141-0001 Japan ZHT
[Manufacturer locale: SONY Corp., China]
[Serial Number: unknown]
3. SONY(®) “Digital Tuner/CD Player Walkman” with G-Protection
[Model Name: RADIO/CD WALKMAN Model Number: D-FJ210]
Manufacturer Address:
Sony Corporation
6-7-35 Kitashinagawa; Shinagawa-ku, Tokyo, 141-0001 Japan ZHT
[Manufacturer locale: SONY Corp., China]
[Serial Number: unknown]
4. Durabrand(®) CD 855 Programmable CD player with ESP and Remote Control
[Model Name: Durabrand CD 855 Model Number: CD 855]
Manufacturer Address:
Lennox Electronics, Corp.
2 Germak Drive, Carteret, N.J. 07008
[Manufacturer locale: Lenoxx Electronics, Corp., China]
[Serial Number: unknown]
Tools and Materials Utilized:
1. ABS Plastic 2. One cellular telephone belt-carrying clip. 3. One piece of neoprene rubber 4. (Chemical Compound): SEM(®) 39768 part B “Problem Plastic Repair Material” 5. (Chemical Compound): Crazy Glue(™). 6. One Plastic Cutting Blade. 7. One 0.7 KW heat gun with adjustable thermal control. 8. Miniature tweezers.
Method of Manufacture:
note: The original working prototype was meant to engage one particular compact disc player model from one particular manufacturer.
1. We cut the cellular telephone's belt-carrying clip with a standard plastic cutting blade. 2. We proceeded to measure and cut the piece of ABS plastic to the proper dimensions we wanted with a standard plastic cutting blade. 3. We cut the ABS plastic to the following dimensions:
Length: 3 inches Width: ½ inches Thickness: 1/16 inches
4. We then proceeded to remove the excess amount of ABS plastic no longer needed for the particular shape we had in mind. 5. Using a heat gun and miniature tweezers, we proceeded to shape the bottom half of the previously cut cellular telephone's belt-carrying clip. In this manner, we made it accommodate and engage in a secure manner, the bottom of the compact disc player. Using the heat gun, we molded the lower portion of the compact disc player's carrier to be accepted by the groove provided by the manufacturer of the compact disc player. 6. When we were assured this section of the device was finished to our satisfaction, we then proceeded to measure and cut the 3-inch piece of ABS plastic to the proper length needed in order to have the upper portion of the cellular telephone's belt carrying clip be accepted by the existing lip provided by the compact disc player. 7. We then proceeded to mix the two part epoxy to secure the piece of ABS plastic cut to the proper dimensions to extend the upper portion of the clip and attach it to the lower portion of the clip to accept the proper device at hand, which happened to be a compact disc player. 8. We then used a piece of rubber 1 inch-square by one-sixteenth inch thick for the prevention of any potential slippage or sliding of the compact disc player when engaged to the portable electronic information and/or entertainment rendering device carrier. 9. We then cut to the proper size the upper portion of the cellular telephone's belt-carrying clip. Using Crazy Glue(™), we glued the 1 inch-square by one-sixteenth inch thick rubber piece to this upper portion where the center base of the clip meets the compact disc player's back. 10. In turn, the upper portion of the clip did not need any modification at hand. 11. In this manner, the portable electronic information and/or entertainment rendering device carrier is finished and ready to be used for the portable compact disc player.
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It is a carrier for portable electronic information and/or entertainment rendering devices. The carrier engages the contour(s) and/or edge(s) of the aforementioned devices and by means of frictional surface forces prevents slippage. It is an attacheable and detacheable carrier. The carrier attaches to the portable information and/or entertaiment rendering devices by means of hooks and frictional force. The carrier attaches to the user by means of a spring-loaded hook.
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CROSS-REFERENCE TO RELATED APPLICATIONS
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not Applicable.
BACKGROUND OF THE INVENTION
Mounting fabric in preparation for being embroidered requires hoop means which places the area of the fabric to be embroidered under tension to meet the requirement of what every type of machine is to be used to apply a desired design or lettering or art work to the fabric.
The prior art which relates to framing fabric for embroidery work includes such complicated apparatus as can be found in prior art patents such as U.S. Pat. Nos. 4,545,127 of Oct. 8, 1985; 4,561,177 of Dec. 31, 1985; 4,767,111 of Aug. 30, 1985; 5,432,990 of Jul. 18, 1995; and 4,805,297 of Feb. 21, 1989. These examples of the art require complicated apparatus for handling fabric to which embroidery designs are to be applied. The complication adds cost and requires individuals of mechanical ability.
In other words the embroidery hoop apparatus of the character found in the art is expensive and embodies complicated apparatus for accomplishing the end results in the field of embroidery work.
OBJECTS OF THE INVENTION
It is the desire to avoid complicated embroidery hoop apparatus by providing simple hoop supporting boards that offer a range of sizes of fabric all reduced to simple manipulation for supporting hoops at desired locations on fabric to suit a variety of embroidery machines.
A further object of the invention is to embody hoop apparatus for accommodating a variety of sizes of fabric items in a single board adapted to receive selected sizes of fabric items.
Another object of the invention is to provide a fabric supporting board that allows for selectivity of location of embroidery hoop to accommodate embroidery work suitable for children through adult sizes.
Yet another object of the invention is to provide a conventional size of board which is easily portable and does not require misshaping garments to accomplish the creation of designs suitable for embroidery work.
These and other objects pertaining to the important embroidery hoop apparatus will be apparent from the description of this invention.
BRIEF SUMMARY OF THE INVENTION
The invention comprises a board means for applying embroidery hoop means to a garment or fabric for framing the fabric to receive embroidery whereby the framed fabric can be removed from the board means and brought to a program driven embroidery machine so the embroidery work can be located on the fabric framed in the hoop means.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
In the drawings, FIG. 1 is a plan view in slanted elevation of the hoop supporting board suitable for selective sizes of fabric;
FIG. 2 is a back side of the hoop supporting board of FIG. 1;
FIG. 3 is a side elevation taken along 3--3 in FIG. 2;
FIG. 4 is a side elevation of the board of FIG. 2 with one size board laid back to reduce the fabric size for the remaining board;
FIG. 5 is a side view of FIG. 2 with the central sleeve side board laid out from the board;
FIG. 6 is a perspective view of a typical board slidable support;
FIG. 7 is a fragmentary view of a typical hinge for the several boards;
FIG. 8 is a plan view of the hinge of FIG. 7;
FIG. 9 is a plan view of a typical female hoop of adjustable size; and
FIG. 10 is a view of a typical male hoop.
Corresponding reference numerals will be used throughout the several figures of the drawings.
DETAILED DESCRIPTION OF THE INVENTION
The view of FIG. 1 illustrates the adjustable female embroidery hoop having the size adjustment element 12 which is intended to accommodate fabric thickness in order to receive a male hoop seen in FIG. 10. The board of FIG. 1 is composed of a stationary central board 13 having a pair of straight outer edges 14 merging at the top in a shaped form 15. The stationary central board 13 is fitted to an inner hinged board 16 having a pair of straight legs with sides 17 and a connective top 18 following the shape of the top 15 for the stationary central board 13. The inner hinged board 16 is fitted with an outer board 19 having a pair of straight legs 20 connected by a formed top connection 21. The bottom ends of the inner board is connected to a base 22 by the hinge leaf 23 of a hinge plate 24 seen in FIG. 8. That hinge plate 24 has an outer leaf 25 attached to the bottom of the legs 20 of the outer board 19.
As seen in FIGS. 1 and 2, the respective outer, inner and central boards are intended to line up in a common plane by the alignment slide blocks 26 (see FIG. 6) which are attached to the rear side of the several boards 13, 16 and 19. Since those boards are formed from a transparent sheet of plastic the slide blocks 26 can be seen in FIGS. 1 and 2.
The board assembly seen in FIGS. 1 and 2 are provided with a small fabric sleeve board 27 which is fitted between the support braces 28 for the adjacent larger board 13 which is not hinged. That board 13 is held in a slanted position (see FIGS. 3, 4 and 5) and is provided with a pair of aligned hinge pins 29 located by bearing plates 30 carried in the slanted surfaces of the braces 28. That fabric sleeve board swings on the pins 29 into frontal position relative to the slanted board assembly in FIG. 5. As the board swings out, its rear end 27A abuts a stationary stop rod 31 which limits the angle of projection. In addition to the abutment stop 31 there is provided a removable support element 32 (FIG. 5) which can be set in place on a pin 33, and when the board 27 is swung back into the plane of the other boards that support element 32 needs to be removed so it will not interfere with fabric slipped over the slanted boards.
When it is necessary to hinge either of the boards 16 or 19 to a laid back position, as seen in FIG. 4, there is a support rod 34 positioned on the base 22. In order to be able to swing either or both of the boards 16 and 19 to a laid back position it is first necessary to slide the blocks 26 inwards so the edges of the boards 16 or 19 clear the blocks 26. But when the boards 16 and 19 are returned to the slanted up position there are stop elements at the top edges to position the boards correctly. The first stop 35 is on the top of the sleeve board 27. A second stop 36 on top of the stationary board positions the board 16 and finally a stop 37 on the top of the board 16 positions the board 19. Thus, the several stops 35,36 and 37 serve the purpose to align the several separate boards in the same plane.
FIGS. 9 and 10 illustrate the female and male hoops which are seen in FIG. 1. As before noted the female hoop 11 is made to have an inner circumferential dimension so that as fabric gets thicker that hoop must be made large to allow the fixed dimension of the male hoop 38 to fit into the female hoop 11 and exert a tension in the fabric laid over the female hoop with sufficient tension in the fabric to allow the male hoop to reach an inset position. In order to allow the fabric and the hoops 11 and 38 to stay together and be removed from the hoop boards, the female hoop 11 is provided with mounting plates 39 with locating pins 40 which initially are inserted in the proper aperture 41 in the respective boards for that purpose which allows female hoop to fine positions on one or more boards in the aperture 41 shown in the view of FIGS. 1 and 2. The utility of the foregoing apparatus is to be understood as providing a frame F having a shaped surface over which fabric material may be fitted in preparation that the attachment of female and male embroidery hoops 11 and 38 respectively may be applied. The initial step in embroidery work, which may be applied to the fabric, which may be an article of clothing, a table cover or other fabric item, is to select a target area on the frame so the projections 40 on the female hoop 11 can be inserted in the selected aperture in the frame surface for support. The fabric may then be placed on or over the frame to cover the female hoop 11 in alignment with the target area. That mounting of the fabric is followed by adjusting the inner circumferential dimension of the female hoop by the sizing adjustment element 12 to suit the thickness of the fabric to allow the male hoop 38 to be press-fitted into the female and subject the fabric within the hoop to a desired tension so the embroidery machine can be satisfied.
While the invention has been described in connection with specific means, it should be understood that the description is made only by an example and is not intended to limit the scope of the invention as it may be defined by the scope of the following claims.
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Apparatus for promoting embroidery work on fabric such as clothing, comprising a board frame for receiving the fabric to be embroidered through the mounting of hoops on the board to prepare an area of the fabric for embroidery, and to boards being constructed to fit different sizes of fabric material.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a 1-amino-2-cyclohexene derivative useful as an intermediate in the production of various medicines and agricultural agents and a production process therefor.
2. Discussion of the Background
Recently, condensed ring compounds containing hetero atoms (such as oxygen, nitrogen and sulfur) have been found to have various biological activities and vigorous developments have been made for them as medicines and agricultural agents. For example, Amemiya et al. have reported a dihydrobenzothiophene derivative or a tetrahydrobenzothiophene derivative having an inhibitory action on thromboxane synthetase (Journal of Medicinal Chemistry, 1989, vol. 32, pp. 1265-1272). Nagai et al. have reported a carbazole-3,4-dicarboximide derivative having anti-tumor activity (Japanese Patent Laid-Open No. 4-178387). Additionally, Dubroeucg et al. have reported a benzofuran or a benzothiophene carboxamide which has an effect as a tranquilizer, anti-anginal drug and immunomodulator (Japanese Patent Laid-open No. 63-39874).
Various studies have also been made for production processes for the condensed ring compounds. For condensed ring forming reactions, one method of bonding together the side chains of cyclic compounds having two side chains is the Robinson annelation. For example, Amemiya et al. obtain 4,5-dihydrobenzo[b]thiophene-6-carboxylic acid methyl ester by forming 7-oxo-4,5,6,7-tetrahydrobenzo[b]thiophene using 3-bromothiophene as a starting material (MacDowell et al., Journal of Heterocyclic Chemistry, 1965, vol. 2, pp. 44-48), methoxycarbonylating the same, reducing the ketone and then dehydrating with an acid. Further, in the method of Nagai et al., a carbazole skeleton is formed according to the Fisher indole synthesis using N-benzyl-4-oxocyclohexane-1,2-carboximide as the starting material and then reacting the same with phenylhydrazine. In Dubroeucg et al., 4-phenylbenzo[b]thiophene-6-carboxylic acid was obtained by condensing 3-benzoylpropionic acid and 2-thiophene carboxy aldehyde in the presence of acetic anhydride and potassium acetate to obtain 5-phenyl-3-(2-thienylmethylene)-2-furanone and heating the same in acetic acid in the presence of methane sulfonic acid. Kido et al. report a method of constructing the 2,4,5,6,7,7a-hexahydrobenzofuran-2-one skeleton by the condensation reaction of 2-methyl-3-vinylbutenolide and 2-formyl-6-methyl-5-heptenic acid methyl ester and then introducing the same to furoventalene having a benzofuran skeleton isolated from sea fan (Gorgonia ventalina) (Journal of Organic Chemistry, 1981, vol. 46, pp. 4264-4266).
As described above, condensed ring compounds are useful as intermediate products for the synthesis of various medicines and agricultural agents. However, there are few general production processes for condensed ring compounds, and the development of such general production processes is much in demand. The method described above of bonding side chains of cyclic compounds having two side chains with each other often requires multiple steps for the cyclizing reaction and, accordingly, functional groups that can be introduced may sometimes be restricted depending on the reaction conditions. In addition, the availability of starting materials significantly limits the applicability of such a process as a general process for producing the various desired condensed ring compounds.
On the other hand, cycloaddition reactions, typically represented by the Dieis-Alder reaction, have a feature capable of forming a condensed ring in a single stage since two bonds are formed in the same reaction. Examples include indole alkaloid synthesis by way of indole quinodimethane type diene (Magnus et al., Tetrahedron, 1981, vol, 37, pp. 3889-3897; Journal of American Chemical Society, 1982, vol. 104, pp. 1140-1141; Journal of American Chemical Society, 1983, vol. 105, pp. 4739-4749; Journal of American Chemical Society, 1983, vol. 105, pp. 4750-4757; Journal of American Chemical Society, 1984, vol. 106, pp. 2105-2114 and Accounts of Chemical Research, 1984, vol. 17, pp. 35-41), carbazole synthesis using pyrano[3,4-b]indol-3-one or pyrano[4,3-b]indol-3-one (Doren et al., Tetrahedron, 1989, vol. 45, pp. 6761-6770; Moody et al., Journal of Chemical Society, Perkin Transaction I, 1988, pp. 1407-1415; Journal of Chemical Society, Perkin Transaction I, 1989, pp. 376-377 and Journal of Chemical Society, Perkin Transaction I, 1990, pp. 673-679), and carbazole synthesis using vinyl indole (Pindur et al., Helvetica Chimica Acta, 1988, vol. 71, pp. 1060-1064; and Journal of Organic Chemistry, 1990, vol. 55, pp. 5368-5374).
Although the above-mentioned methods are excellent in being single stage condensed ring-forming reactions, the method of Magnus et al. is only used in the intramolecular Dieis-Alder reaction, while the method of using pyranoindol-3-one or vinyl indole requires multiple stages and/or special steps for the preparation of starting materials and further requires expensive starting materials and reagents. These methods thus cannot thoroughly take advantage of the single stage cyclization reaction from an industrial point of view. Further, each of the processes is applied only to carbazole derivatives, and thus cannot be said to be a general method for synthesizing condensed ring compounds.
SUMMARY OF THE INVENTION
Accordingly, one object of the present invention is to provide a novel intermediate product which can be used to make various condensed ring compounds.
Another object of the present invention is to provide a process for producing such intermediate products in a minimum number of steps and at a high yield taking advantage of the feature of the cycloaddition reaction, using easily available starting materials and without using expensive reagents.
These and other objects of the present invention have been satisfied by the discovery of 1-amino-2-cyclohexene derivatives and a production process therefor, wherein the 1-amino-2-cyclohexene derivatives are useful in the preparation of medicinal and agricultural agents.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention relates to a 1-amino-2-cyclohexene derivative represented by the following formula (I): ##STR2## where A represents a bivalent organic group which may contain 1 to 3 oxygen atoms, nitrogen atoms and/or sulfur atoms, wherein A may form a ring having a total of 5-8 members, and the ring may form a condensed ring with one or more additional rings; R 1 represents a hydrogen atom, an alkyl group, an alkenyl group, an aryl group or an aralkyl group, R 2 represents a hydrogen atom, an alkyl group, an alkenyl group, an aryl group, an aralkyl group, a cyano group or a group represented by the formula: --COR 21 , where R 21 represents a hydrogen atom, an alkyl group, an alkenyl group, an aryl group, an aralkyl group, an alkoxy group, an alkenyloxy group, an aryloxy group, an aralkyloxy group or an amino group which may have a substituent, R 3 represents a cyano group, a nitro group or a group represented by the formula: --COR 31 , where R 31 represents a hydrogen atom, an alkyl group, an alkenyl group, an aryl group, an aralkyl group, an alkoxy group, an alkenyloxy group, an aryloxy group, an aralkyloxy group or an amino group which may have a substituent, R 4 represents an alkyl group, an alkenyl group, an aryl group or an aralkyl group, R 5 represents a hydrogen atom, an alkyl group, an alkenyl group, an aryl group, an aralkyl group, an alkoxy group, an alkenyloxy group, an aryloxy group, an aralkyloxy group or an amino group which may have a substituent, in which R 2 and R 31 may join together to form a bivalent organic group optionally containing an oxygen atom or a nitrogen atom; and
a process for producing a 1-amino-2-cyclohexene derivative (I) which comprises condensing an aldehyde represented by the formula (II): ##STR3## where A and R 1 are as defined above with a primary amine represented by the following formula (III):
H.sub.2 NR.sup.4 (III):
where R 4 is as defined above to obtain an imine represented by the following formula (IV): ##STR4## where A, R 1 and R 4 are as defined above, and reacting the imine (IV) in the presence of a basic substance with a carbonylating agent represented by the following formula (V): ##STR5## where R 5 is as defined above and X represents a leaving group, and an ethylene derivative represented by the following formula (VI):
R.sup.2 --CH═CH--R.sup.3 (VI)
where R 2 and R 3 are as defined above, [hereinafter referred to as dienophile (VI)]; and
a process for producing a 1,3-cyclohexadiene derivative represented by the following formula (IX): ##STR6## where A, R 1 , R 2 and R 3 are as defined above, which comprises subjecting the 1-amino-2-cyclohexene derivative (I) to an elimination reaction by a basic substance.
Examples of a ring formed by A include 5-membered rings such as a cyclopentene ring, a cyclopentadiene ring, a dihydrofuran ring, a furan ring, a pyrrole ring, a pyrroline ring, a dehydrodioxolane ring, a pyrazole ring, a pyrazoline ring, an imidazole ring, an oxazole ring, an isoxazole ring, a thiazole ring, an oxadiazole ring and a triazole ring; 6-membered rings such as a benzene ring, a cyclohexadiene ring, a cyclohexene ring, a pyran ring, a dihydropyran ring, a pyridine ring, a dihydropyridine ring, a tetrahydropyridine ring, a dehydrodioxan ring, a dehydromorpholine ring, a pyridazine ring, a dihydropyridazine ring, a tetrahydropyridazine ring, a pyrimidine ring, a dihydropyrimidine ring, a tetrahydropyrimidine ring, a pyrazine ring and a dihydropyrazine ring; 7-membered rings such as a cycloheptatriene ring, a cycloheptadiene ring, a cycloheptene ring, as well as aza, oxa or thia substituted derivatives thereof, and a thiazepin ring; and 8-membered rings such as a cyclooctatetraene ring, a cyclooctatriene ring, a cyclooctadiene ring, a cyclooctene ring as well as aza, oxa or thia substituted derivatives thereof.
Where the ring formed by A forms a condensed ring with one or more other rings, A can include a benzofuran ring, an isobenzofuran ring, a chromene ring, an indolizine ring, an isoindole ring, an indole ring, a quinolizine ring, an indazole ring, an isoquinoline ring, a quinoline ring, a phthalazine ring, a naphthyridine ring, a quinoxaline ring, a quinazoline ring, a benzothiophene ring and the hydrogenated forms thereof. Any of the above rings may have a substituent.
In the present invention, "alkyl" includes linear or branched alkyl groups of 1 to 8 carbon atoms such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tertbutyl, pentyl, isopentyl, neopentyl, hexyl, heptyl and octyl; and cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl. "Alkenyl" includes vinyl, allyl, methallyl, butenyl, plenyl and octenyl.
"Aryl" includes phenyl or naphthyl, either of which may have a substituent. Specific examples include phenyl, naphthyl, fluorophenyl, chlorophenyl, bromophenyl, methoxyphenyl, nitrophenyl, tolyl, xylyl and isopropylphenyl. "Aralkyl" includes benzyl which may have a substituent, such as benzyl, methoxybenzyl, dimethoxybenzyl, nitrobenzyl, chlorobenzyl and bromobenzyl.
"Alkoxy" includes linear or branched alkoxy groups of 1 to 8 carbon atoms, such as methoxy, ethoxy, propoxy, isopropoxy, butoxy, hexyloxy and octyloxy; and cycloalkyloxy groups such as cyclopentyloxy and cyclohexyloxy. "Alkenyloxy" includes alkenyloxy groups of 1 to 8 carbon atoms such as allyloxy, methallyloxy, plenyloxy and octenyloxy.
"Aryloxy" includes phenoxy which may have a substituent, such as phenoxy, methylphenoxy, methoxyphenoxy, chlorophenoxy, bromophenoxy and nitrophenoxy. "Aralkyloxy" includes benzyloxy which may have a substituent, such as benzyloxy, chlorobenzyloxy, bromobenzyloxy, methoxybenzyloxy, methylbenzyloxy and nitrobenzyloxy. "Amino group having a substituent" includes secondary amino groups substituted with aralkyl, alkylene, aryl and/or aralkyl, such as dimethylamino, diethylamino, N-phenylmethylamino, N-benzylmethylamino and 1-pyrrolidyl.
The leaving group represented by X in the general formula (V) includes halogen, such as chlorine and bromine; and acyloxy, such as acetoxy, propionyloxy, butylyloxy and valeryloxy.
As an example of 1-amino-2-cyclohexene derivative (I), there can be mentioned a tetrahydrobenzothiophene derivative or a tetrahydrobenzofuran derivative represented by the following general formula (I-1): ##STR7## where each of R 32 , R 41 and R 51 represents an alkyl group, an aryl group or an aralkyl group and Y represents a sulfur atom or an oxygen atom, and a tetrahydrocarbazole derivative represented by the following general formula (I-2): ##STR8## (where R 32 , R 41 and R 51 are as defined above, and R 6 represents an alkyl group, an aralkyl group, an acyl group, an alkoxycarbonyl group, an alkanesulfonyl group or an arenesulfonyl group).
Examples of the aldehyde (II) include a 3-methylthiophene-2-aldehyde or a 3-methylfuran-2-aldehyde represented by the following formula (VII): ##STR9## where Y is as defined above, or 2-methylindole-3-aldehyde represented by the following formula (VIII): ##STR10##
Examples of the 1,3-cyclohexadiene derivative (IX) include a dihydrobenzothiophene carboxylic acid derivative or a dihydrobenzofuran carboxylic acid derivative represented by the following general formula (IX-11): ##STR11## where R 32 and Y are as defined above, or a dihydrocarbazol carboxylic acid derivative represented by the following general formula (IX-21): ##STR12## where R 32 and R 6 are as defined above.
Compound (IX-11) and compound (IX-21) can be transformed, if necessary, by subjecting them to hydrolysis to obtain a dihydrobenzothiophene carboxylic acid derivative or a dihydrobenzofuran carboxylic acid derivative represented by the following general formula (IX-1): ##STR13## where Y is as defined above and R 33 represents a hydrogen atom, an alkyl group, an aryl group or an aralkyl group, or a dihydrocarbazol carboxylic acid derivative represented by the following general formula (IX-2): ##STR14## where R 33 and R 6 are as defined above, respectively.
In compounds (I-2), (IX-2) and (IX-21), R 6 is preferably a group used conventionally as a protecting group for nitrogen in indole. More specifically, the alkyl groups and aralkyl groups which may be used are those described previously. The acyl groups include alkanoyl groups which may have a substituent, such as formyl, acetyl, propionyl, butyryl, isobutyryl, valeryl, isovaleryl, pivaloyl, chloroacetyl and trifluoroacetyl; and benzoyl or naphthoyl groups which may have a substituent, such as benzoyl, methoxybenzoyl, chlorobenzoyl and naphthoyl. The alkoxycarbonyl groups of R 6 include lower alkoxycarbonyl groups such as methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, isopropoxycarbonyl, butoxycarbonyl and tert-butoxycarbonyl; aryloxycarbonyl groups which may have a substituent, such as phenoxycarbonyl and nitrophenoxycarbonyl; and aralkyloxycarbonyl groups which may have a substituent, such as benzyloxycarbonyl and methoxybenzyloxycarbonyl. The alkane sulfonyl groups of R 6 include methane sulfonyl and ethane sulfonyl. The arene sulfonyl groups of R 6 include benzene sulfonyl, toluene sulfonyl and bromobenzene sulfonyl.
Conversion from the aldehyde (II) to the imine (IV) is conducted by condensing the aldehyde (II) with the amine (III). The reaction can be conducted under conventional conditions used generally for obtaining an imine from an aldehyde and a primary amine. For example, the conversion can be conducted by mixing the aldehyde (II) and the amine (III) in the presence or absence of a solvent. Suitable solvents are those which give no undesired effect on the reaction, including aliphatic hydrocarbon solvents such as pentane, hexane, heptane and ligroin; aromatic hydrocarbon solvents such as benzene, toluene, xylene and chlorobenzene; ether solvents such as diethyl ether, tetrahydrofuran and dioxane; alcohol solvents such as methanol and ethanol; ester solvents such as methyl acetate, ethyl acetate and butyl acetate; or a mixture thereof, and reacting in the presence or absence of a dehydrating agent, such as silica gel, molecular sieves, alumina, sodium sulfate, magnesium sulfate and copper sulfate.
Further, reaction may also be conducted in an azeotropic solvent with water while removing water by azeotropic distillation.
Isolation and purification from a reaction mixture of the thus obtained imine (IV) is conducted using conventional techniques. For instance, the imine (IV) can be obtained by separating insoluble matter contained in the reaction mixture by filtration, condensing the liquid filtrate, recrystallizing residues and then purifying, for example, by chromatography. Further, crude products can be used as they are obtained, without purification, in the succeeding reaction. When the resultant imine (IV) is deposited from the reaction mixture, it is recovered by filtration and purified if necessary, by recrystallization and then can be used in a succeeding reaction.
Conversion from the imine (IV) to the 1-amino-2-cyclohexene derivative (I) is conducted in the presence of a basic substance by reacting imine (IV) with carbonylating agent (V) and dienophile (VI). As the carbonylating agent used herein, there can be mentioned carboxylic acid anhydrides, such as acetic anhydride, propionic anhydride, butyric anhydride, valeric anhydride and trifluoro acetic anhydride; carboxylic acid halides, such as acetyl chloride, propionyl chloride, butyryl chloride, isobutyryl chloride, valeryl chloride, isovaleryl chloride, pivaroyl chloride and benzoyl chloride; chloroformate esters, such as methyl chloroformate, ethyl chloroformate, propyl chloroformate, isopropyl chloroformate, butyl chloroformate, allyl chloroformate, phenyl chloroformate, nitrophenyl chloroformate and benzyl chloroformate; carbamic acid halides, such as N,N-dimethyl carbamic acid chloride. Among these, chloroformate esters are preferred. The amount of the carbonylating agent (V), while different depending on the type used, ranges from 0.5 to 20 mol, preferably, from 1.1 to 10 mol based on one mol of the imine (IV).
As the dienophile (VI), there can be mentioned acrylates which may have a substituent, acrylamides which may have a substituent, acrylonitrile which may have a substituent, propenal which may have a substitutent, vinyl ketones which may have a substituent, maleic acid esters, maleic anhydride, maleimides, fumaric acid esters, fumaronitrile and nitroethylene which may have a substituent. More specific examples include alkyl acrylates such as methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, butyl acrylate, isobutyl acrylate, sec-butyl acrylate, tert-butyl acrylate, pentyl acrylate, hexyl acrylate, cyclopentyl acrylate and cyclohexyl acrylate; aryl acrylates, such as phenyl acrylate, naphthyl acrylate, chlorophenyl acrylate, bromophenyl acrylate, methoxyphenyl acrylate, nitrophenyl acrylate, tolyl acrylate, xylyl acrylate and isopropylphenyl acrylate; aralkyl acrylates, such as benzyl acrylate, methoxybenzyl acrylate, dimethoxybenzyl acrylate, nitrobenzyl acrylate, chlorobenzyl acrylate and bromobenzyl acrylate; substituted acrylates, such as methyl crotonate and methyl succinate; N-substituted acrylamides, such as N,N-dimethylacrylamide; substituted acrylamides, such as N,N-dimethylcrotonamide and N,N-dimethylcinnamamide; acrylonitrile; aromatic-substituted acrylonitriles, such as crotononitrile and cinnamonitrile; acrolein; substituted propenals, such as crotonaldehyde and cinnamaldehyde; vinyl ketones, such as methyl vinyl ketone, ethyl vinyl ketone, phenyl vinyl ketone, styryl methyl ketone, 3-penten-2-one and 1-penten-3-one; maleates, such as dimethyl maleate; maleic anhydride; fumarates, such as dimethyl fumarate; maleimides, such as N-phenyl maleimide; fumaronitrile and vinyl nitro compounds such as nitroethylene. The amount of dienophile (VI) used ranges from 0.5 to 50 mol, preferably from 1.1 to 10 mol, based on 1 mol of the imide (IV).
The basic substance used for the reaction includes tertiary amines such as trimethyl amine, triethyl amine, tributyl amine, trihexyl amine, trioctyl amine, diisopropyl ethyl amine, dimethyl aniline, diethyl aniline and N-methylmorpholine; alkali metal carbonates, such as lithium carbonate, sodium carbonate and potassium carbonate; alkali metal hydroxides, such as lithium hydroxide, sodium hydroxide and potassium hydroxide; alkaline earth metal hydroxides, such as magnesium hydroxide and calcium hydroxide; and metal hydrides, such as a lithium hydride and sodium hydride. Among these, a sterically hindered (i.e. bulky) tertiary amine which exhibits relatively high basicity and is soluble in the reaction system, such as diisopropyl ethyl amine, is preferred. The amount of the basic substance used ranges from 0.5 to 50 mol, preferably from 1.1 to 10 mol, based on one mol of the imine (IV). The amount is preferred to be more than 1 mol per 1 mol of the carbonylating agent (V) used.
The conversion reaction from imine (IV) to 1-amino-2-cyclohexene derivative (I) can be conducted with or without solvent. When the reaction is conducted in a solvent, there is no particular restriction on the solvent to be used so long as it does not give any undesired effect on the reaction. Suitable solvents include aromatic hydrocarbon solvents, such as benzene, toluene, xylene, chlorobenzene, trimethylbenzene and cumene. The amount of the solvent used preferably ranges from 3 to 200 times by weight based on the imine (IV).
The reaction temperature may vary depending on the solvent, the carbonylating agent (V) and the dienophile (VI) used and is preferably within a range from 40° C. to the reflux temperature for the reaction system. The reaction time, which may vary depending on the reaction temperature, preferably ranges from 30 minutes to 24 hours. By properly controlling the reaction temperature, the reaction time can be controlled.
The conversion reaction described above can be practiced, for example, as shown below. Dienophile (VI) and the basic substance are added to the solution of imine (IV), and carbonylating agent (V) is added to the resultant mixture within a temperature range from under ice cooling (0° C.) to the reflux temperature of the reaction mixture. After the completion of the addition, the mixture is heated to the desired temperature until imine (IV) disappears.
Isolation and purification of the thus obtained 1-amine-2-cyclohexene derivative (I) from the mixture is conducted using conventional organic purification methods. For instance, after cooling the reaction mixture to a room temperature, it is washed with an aqueous solution of sodium hydrogen carbonate and saline water, dried on sodium sulfate and the solvent is then distilled off to obtain a crude product.
Conversion from 1-amino-2-cyclohexene derivative (I) to 1,3-cyclohexadiene derivative (IX) is conducted in the presence of a basic substance by subjecting 1-amino-2-cyclohexene derivative (I) to an elimination reaction.
The basic substance used for the elimination reaction is not particularly limited so long as the substance does not cause side reaction and has sufficient basicity to cause elimination to form the 1,3-cyclohexadiene derivative (IX). Suitable basic substances include metal alkoxides, such as lithium methoxide, sodium methoxide, potassium methoxide, sodium ethoxide, potassium ethoxide, potassium tert-butoxide and sodium tert-amyloxide; metal amides, such as lithium amide, sodium amide, potassium amide, lithium diisopropyl amide, lithium cyclohexyl isopropyl amide, lithium hexamethyl disilazide, sodium hexamethyl disilazide, potassium hexamethyl disilazide and lithium tetramethyl piperizide; amines, such as diazabicyclo[2.2.21]octane (DABCO) and diazabicycle[5.4.0]undec-7-ene (DBU); and quaternary ammonium hydroxides, such as trimethyl benzyl ammonium hydroxide, and tributyl ammonium hydroxide. In the case of quarternary ammonium hydroxides, the quaternary ammonium hydroxide can be formed in the system from a corresponding halide and an alkali metal hydroxide. The amount of the basic substance used ranges from 0.8 to 20 mol, preferably from 0.95 to 10 mol, based on one mol of the 1-amino-2-cyclohexene derivative (I).
The elimination reaction is usually conducted in a solvent and the solvent used varies depending on the basic substance used. Suitable solvents include alcohol solvents, such as methanol, ethanol, propanol, isopropyl alcohol and tert-butyl alcohol; ether solvents, such as diethyl ether, tetrahydrofuran, dioxane and 1,2-dimethoxy ethane; polar aprotic solvents, such as N,N-dimethylformamide and dimethyl sulfoxide; hydrocarbon solvents, such as hexane, heptane, cyclohexane, petroleum ether and ligroin; aromatic hydrocarbon solvents, such as benzene, toluene and xylene; water; or a mixture thereof. The amount of the solvent used preferably ranges from 3 to 200 times by weight based on 1-amino-2-cyclohexene derivative (I).
The reaction temperature for the elimination reaction, while different depending on the basic substance and the solvent used, preferably ranges from 0° C. to 150° C. The reaction temperature varies depending on the reaction temperature and preferably ranges from 30 minutes to 24 hours.
Isolation and separation of the thus obtained 1,3-cyclohexadiene derivative (IX) from the reaction mixture can be performed using conventional organic methods. For instance, 1,3-cyclohexadiene derivative (IX) can be obtained by adding the reaction mixture to iced water, separating an organic layer, then extracting an aqueous layer with an organic solvents, such as ethyl acetate, diethyl ether, dichloromethane or toluene, collecting the organic layer and washing with an aqueous sodium chloride solution, drying over sodium sulfate or magnesium sulfate and then concentrating to obtain a crude product, which is purified, for example, by recrystallization and/or chromatography. Further, it is possible to use the crude products as they are obtained, with no further purification, in the succeeding reaction or use the reaction mixture without isolation or purification in the succeeding reaction.
The 1,3-cyclohexadiene derivative (IX) in which R 3 represents a group represented by the formula --COR 31 , and R 31 represents an alkoxy group, an alkenyloxy group, an aryloxy group or an aralkyloxy group, can be converted by hydrolysis into a 1,3-cyclohexadiene carboxylic acid derivative represented by the following general formula (IX-3): ##STR15## where A and R 1 are as defined above, R 22 represents R 2 or carboxyl group, and R 2 is as defined above. The carboxylic acid (IX-3) is a compound included in the 1,3-cyclohexadiene derivative (IX).
The hydrolysis reaction can be conducted in accordance with a conventional method used to convert an ester to a corresponding carboxylic acid. For instance, it can be conducted by adding an aqueous solution containing a sufficient amount of an alkali metal hydroxide for hydrolysis to the 1,3-cyclohexadiene derivative (IX) in which the group represented by R 3 is an alkoxy carbonyl group, an alkenyloxy carbonyl group, an aryloxy carbonyl group and an aralkyloxy carbonyl group, or a solution thereof, and stirring at a temperature within a range from 0° C. to 100° C. till the 1,3-cyclohexadiene derivative (IX) in which the group represented by R 3 is an alkoxy carbonyl group, an alkenyloxy carbonyl group, an aryloxy carbonyl group, an aralkyloxy carbonyl group disappears completely.
Isolation and purification of the thus obtained carboxylic acid (IX-3) from the reaction mixture can be conducted using conventional organic techniques. For instance, a crude product is obtained by distilling off low boiling ingredients of the reaction mixture, adding water as necessary to the resultant residue, extracting the same with an organic solvent such as ethyl acetate, diethyl ether, dichloromethane or toluene, rendering the aqueous layer acidic, with, for example, hydrochloric acid, then extracting with an organic solvent such as ethyl acetate, diethyl ether or dichloromethane, washing the liquid extract with an aqueous sodium chloride solution, then drying by using sodium sulfate or the like and distilling off the solvent. The crude product is then purified, for example, by chromatography or recrystallization to obtain the carboxylic acid (IX-3).
The thus obtained carboxylic acid (IX-3) can be converted into the 1,3-cyclohexadiene derivative (IX) by esterification under conventional conditions.
Among the 1,3-cyclohexadiene derivatives (IX), the compound represented by the following formula (IX-12): ##STR16## can be converted into 2-(1-imidazolylmethyl)-4,5-dihydrothianaphthene-6-carboxylic acid, which has an inhibitory action on thromboxane synthetase and is useful in pharmaceuticals in accordance with a method as described in Journal of Medicinal Chemistry, 1989, vol. 32, pp. 1265-1272. Further, the compound represented by the following general formula (IX-13): ##STR17## where Y is as defined above, can be converted by dehydrogenation, hydrolysis and amidation by sec-butylamine and N-methylation into N-sec-butyl-N-methyl-5-phenylbenzo[b]furan-6-carboxamide or N-sec-butyl-N-methyl-5phenylbenzo-[b]thiophene-6-carboxamide having an activity as a tranquilizer, anti-anginal drug and immunomodulator. Further, the compound represented by the following formula (IX-14): ##STR18## can be converted by conjugate addition of cyanide ion, hydrolysis, imidation, debenzylation and dehydrogenation into N-(N-dimethylaminoethyl)-8-hydroxy-1-methyl-9H-carbazol-3,4-dicarboximide having anti-tumor activity.
The aldehyde (II) can be obtained, for example, by formylating the compound represented by the following general formula (X): ##STR19## where A and R 1 are as defined above. For instance, 3-methylthiophene-2-aldehyde can be obtained from 3-methylthiophene, 3-methylfuran-2-aldehyde can be obtained from 3-methylfuran and 2-methylindole-3-aldehyde can be obtained from 2-methylindole by formylation using Vilsmeier's reagent (N,N-dimethylformamide-phosphoroxy chloride), respectively, and the aldehydes are available as commercial products.
Having generally described this invention, a further understanding can be obtained by reference to certain specific examples which are provided herein for purposes of illustration only and are not intended to be limiting unless otherwise specified.
EXAMPLES
Example 1
3-methylthiophene-2-aldehyde (103 g, 0.816 mol) was mixed with hexane (100 ml), to which aniline (74.4 ml, 0.816 mol) was added and stirred at room temperature for 7 hours. After separating deposited crystalline solids by filtration, and washing with hexane, 139.5 g (yield: 85%) of 3-methylthiophene-2-aldehyde phenylimine was obtained. After concentrating the liquid filtrate and stirring at room temperature for a further 12 hours, 7.30 g (yield: 4%) of 3-methylthiophene-2-aldehyde phenylimine was obtained by post treatment in the same manner as above. 1 H-NMR spectra (chemical shift, ppm: in CDCl 3 ); 2.47 (3H, s), 6.92 (1H, d, J=4.9 Hz), 7.15-7.30 (3H), 7.30-7.45 (3H), 8.61 (1H).
3-methylthiophene-2-aldehyde phenylimine (50 g, 0.248 mol), methyl acrylate (224 ml, 2.48 mol) and diisopropyl ethylamine (173 ml, 0.993 mol) were mixed in xylene (1000 ml) and stirred under ice cooling. Methyl chloroformate (76.8 ml, 0.993 mol) was added to the mixture. After completing the addition, the reaction mixture was heated under reflux for 3 hours and then allowed to cool to room temperature. The reaction mixture was washed with an aqueous solution of sodium hydrogen carbonate and an aqueous solution of sodium chloride and dried over sodium sulfate. After distilling off the solvent, 83 g of crude N-methoxycarbonyl-N-phenyl-7-amino-4,5,6,7-tetrahydrobenzo[b]thiophene-6-carboxylic acid methyl ester was obtained.
The thus obtained crude N-methoxycarbonyl-N-phenyl-7-amino-4,5,6,7-tetrahydrobenzo[b]thiophene-6-carboxylic acid methyl ester (83 g) was dissolved in methanol (830 ml), sodium methoxide (95.8 g in 28% methanol solution) was added and stirred at 60° C. for 2 hours and then allowed to cool to room temperature. Water (500 ml) and potassium hydroxide (27.9 g) were added to the reaction mixture and stirred at 60° C. for one hour. After distilling off methanol, water was added to the residue and extracted with toluene. The resultant aqueous layer was rendered acidic with dilute hydrochloric acid and extracted with ethyl acetate. The liquid extract was washed with an aqueous solution of sodium chloride and then dried over sodium sulfate. The solvent was distilled off and the resultant: residue was purified by recrystallization (in methyl acetate/hexane) to obtain 30.9 g (yield: 72.3% from phenylimine) of 4,5-dihydrobenzo[b]thiophene-6-carboxylic acid as a pale yellow crystalline powder. By concentrating and then recrystallizing the filtrate, 4.3 g (yield: 10.1%) of second crystals were obtained. Melting point: 151.5°-153° C. 1 H-NMR spectra (chemical shift, ppm: in CDCl 3 ): 2.70 (2H, m), 2.88 (2H, m), 6.93 (1H, d, J=4.9 Hz), 7.37 (1H, d, J=4.9 Hz), 7.66 (1H, s). Conditions for high speed liquid chromatographic analysis:
Column: Hiber LiCrospher 100 RP-18 (5 μm) 250 mm×4 mm φ (manufactured by Cica-MERCK)
Eluent: methanol/water (volume ratio 1:1) 0.9 ml/min
Column temperature: 45° C.
Detector: UV absorption detector
Wavelength: 254 nm
Retention time: 6.1 min
Purity (surface area percentage): 99.6%
Example 2
3-methylthiophene-2-aldehyde phenylimine (1.92 kg, 9.48 mol), diisopropyl ethyl amine (4.96 kg, 38.34 mol), methyl acrylate (4.13 kg, 47.94 mol) and methyl chloroformate (3.63 kg, 38.4 mol) were mixed in xylene (30 liter) at room temperature and stirred at 80°-100° C. under reflux for 3 hours. After cooling to room temperature, sodium hydrogen carbonate (10% aqueous solution, 10 liter) and water (7 liter) were added. After washing the organic layer with sodium chloride (20% aqueous solution), N-methoxycarbonyl-N-phenyl-7-amino-4,5,6,7-tetrahydrobenzo[b]thiophene-6-carboxyl acid methyl ester was obtained by filtration as crystalline solids (660 g, yield: 20% from imine). 1 H-NMR spectra (chemical shift, ppm: in CDCl 3 ): 0.95-1.23, 1.65-1.85 (joined 1H, m), 1.85-2.25 (1H, m), 2.25-2.75 (2H, m), 2.75-3.20 (1H, m), 3.50-4.00 (1H, br), 3.71 (3H, s), 3.82 (3H, s), 6.85-7.40 (joined 1H, m), 6.60-6.95 (2H, m), 6.95-7.60 (4H, m).
Example 3
N-methoxycarbonyl-N-phenyl-7-amino-4,5,6,7-tetrahydrobenzo[b]thiophene-6-carboxylic acid methyl ester (100 mg, 0.290 mmol) was dissolved in methanol (3 ml), to which sodium methoxide (28% methanol solution, 1 ml) was added and stirred at room temperature overnight. The reaction mixture was poured into ice water and extracted with diethyl ether. After washing the liquid extract with an aqueous solution of sodium chloride and drying over sodium sulfate, the solvent was distilled off. The residue was purified by silica gel column chromatography to obtain 46.7 mg (yield 48%) of 4,5-dihydrobenzo[b]thiophene-6-carboxylic acid methyl ester as white crystalline solids. 1 H-NMR spectra (chemical shift, ppm: in CDCl 3 ): 2.68 (2H, m), 2.84 (2H, m), 3.79 (3H, s), 6.90 (1H, d, J=4.9 Hz), 7.31 (1H, d, J=4.9 Hz), 7.53 (1H, s).
Example 4
4,5-dihydrobenzo[b]thiophene-6-carboxylic acid methyl ester (100 mg, 0.515 mmol) was dissolved in methanol (5 ml), to which potassium hydroxide (1N aqueous solution, 2 ml) was added and stirred under heating and reflux for 3 hours. After allowing the reaction mixture to cool, the methanol was distilled off. The resultant mixture was diluted with water and extracted with toluene. The aqueous layer was rendered acidic by using 1N hydrochloric acid and extracted with ethyl acetate. After washing the liquid extract with an aqueous solution of sodium chloride and drying it over sodium sulfate, the solvent was distilled off. 76 mg (yield: 82%) of 4,5-dihydro[b]thiophene-6-carboxylic acid showing the same physical property values as those obtained in Example 1 was obtained as crystalline solids by recrystallizing the residue (in methyl acetate/hexane).
Examples 5-9
Table 1 shows results of analysis by high speed chromatography when reaction was conducted in the same manner as in Example 2 using various basic substances. In the table, imine represents 3-methylthiophen-2-aldehyde phenylimine, aldehyde represents 3-methylthiophene-2-aldehyde, carbamate represents methyl N-phenyl carbamates, and tetrahydrobenzothiophene represents N-methoxycarbonyl-N-phenyl-4,5,6,7tetrahydrobenzo[b]thiophene-6-carboxylic acid methyl ester.
__________________________________________________________________________Basic Imine-basedSubstance equivalent Reaction HPLC area ratio (%)ExampleCom- Imine-based of methyl time Alde- Carba- Tetrahydro-No. pound equivalent chloroformate (Hr) Imine hyde mate benzothiophene__________________________________________________________________________5 NaOH 4 2 0.5 0 31 14 546 Na.sub.2 CO.sub.3 4 2 5 0 16 6 787 K.sub.2 CO.sub.3 5 4 0.5 0 41 15 448 K.sub.2 CO.sub.3 10 2 0.2 0 60 20 209 LiH 4 2 1.5 0 27 11 62__________________________________________________________________________
Condition for high speed liquid chromatographic analysis:
Column: Hiber LiCrosorb Si-60 (5 μm) 250 mm×4 mm φ (manufactured by Cica-MERCK)
Column temperature: 32° C.
Eluent: hexane/tetrahydrofuran (volume ratio 10:1) 1 ml/min
Detector: UV absorption detector
Wavelength: 254 nm
Example 10
3-methylthiophene-2-aldehyde phenylimine (100 mg, 0.497 mmol) and triethylamine (0.21 ml, 1.49 mmol) were mixed in xylene, to which acetyl chloride (0.14 ml, 1.99 mmol) was added under ice cooling. Methyl acrylate (0.22 ml, 2.48 mmol) was added to the resultant mixture and stirred under reflux for 7 hours. After allowing the reaction mixture to cool, water was added and the mixture was extracted with ethyl acetate. After washing the liquid extract with an aqueous solution of sodium chloride and drying over sodium sulfate, the solvent was distilled off to obtain 300 mg of crude products. Purification by silica gel column chromatography gave 114 mg (yield: 83%) of N-acetyl-N-phenyl-7-amino-4,5,6,7-tetrahydrobenzo[b]thiophene-6-carboxylic acid methyl ester. 1 H-NMR spectra (chemical shift, ppm: in CDCl 3 ): 1.00-1.50 (1H, m), 1.73, 1.86 (joined 3H, s×2), 1.85-2.20 (1H, m), 230-2.85 (2.5H), 2.95-3.20 (0.5H, m), 3.74, 3.82 (joined 3H, s×2), 6.63-6.85 (2H), 7.15-7.70 (5H).
Example 11
N-acetyl-N-phenyl-7-amino-4,5,6,7-benzo[b]thiophene-6-carboxylic acid methyl ester (134 mg, 0.407 mmol) was dissolved in methanol (5 ml), to which sodium methoxide (28% methanol solution; 157 mg, 0.813 mmol) was added and stirred at room temperature. Sodium methoxide (28% methanol solution, 0.16 ml) was then added at 4 hr, 10 hr, and 28.5 hr, respectively, and they were stirred for 35.5 hours at room temperature. After heating the reaction mixture for 45 minutes under reflux, it was allowed to cool to room temperature. The reaction mixture was poured into ice water and extracted with diethyl ether. After washing the liquid extract with an aqueous solution of sodium chloride and drying over sodium sulfate, the solvent was distilled off to obtain 250 mg of crude products. They were purified by silica gel column chromatography to obtain 66 mg (yield: 84%) of 4,5-dihydrobenzo[b]thiophene-6-carboxylic acid methyl ester showing the same physical property values as those obtained in Example 3.
Example 12
2-methylindole-3-carboxaldehyde (10 g, 0.06 mol) was mixed with hexane (40 ml), to which aniline (9.6 ml, 0.11 mol) was added and stirred at 70° C. for 3.5 hours under reflux. Then, toluene (20 ml) was added and dissolved. The mixture was then submitted to silica gel column chromatography. The column was eluted by a developing solvent of hexane/ethyl acetate=3/1 and a fraction containing the desired product was concentrated by distilling off the solvent, to obtain 10.5 g (yield: 75%) of 2-methylindole-3-carboxaldehyde imine. 1 H-NMR spectra (chemical shift, ppm: in CDCl 3 ): 2.63 (3H, s), 7.15-7.42 (8H, m), 8.19 (1H, s), 8.45-8.48 (1H, m), 8.69 (1H, s).
2-methylindole-3-carboxaldehyde imine (100 mg, 4.5 mmol), methyl acrylate (0.194 g, 22.5 mmol) and diisopropyl ethyl amine (0.116 g, 9.0 mmol) were mixed in toluene (2 ml) and stirred at 80° C. Ethyl chloroformate (0.098 g, 9.0 mmol) was added to the mixture. After completing the addition, the reaction mixture was heated for one hour under reflux and allowed to cool to room temperature. Water was added and the mixture was extracted with toluene. The organic layer was washed with an aqueous solution of sodium chloride and dried over sodium sulfate. The solvent was distilled off to obtain crude products of N, 9-bis(ethoxycarbonyl)-N-phenyl-1-amino-1,2,3,4-tetrahydro-9H-carbazole-2-carboxylic acid methyl ester. Silica gel column chromatography using a developing solvent of hexane/ethyl acetate=5/1, gave a fraction containing the desired product. The product was concentrated by distilling off the solvent, to obtain 150 mg (yield: 71.8% from imine) of N,9-bis(ethoxycarbonyl)-N-phenyl-1-amino-1,2,3,4-tetrahydro-9H-carbazole-3-carboxylic acid methyl ester. 1 H-NMR spectra (chemical shift, ppm: in CDCl 3 ): 1.15-1.25 (3H, m), 1.40-1.51 (3H, m), 1.88-2.19 (2H, m), 2.68-2.91 (2H, m), 2.95-3.11 (1H, m), 3.75 (3H, s), 4.15-4.32 (2H, m), 4.40-4.51 (2H, m), 6.25-6.35 (1H, d, J=7.9 Hz), 6.75-6.88 (2H, m), 7.10-7.20 (2H, m), 7.22-7.38 (2H, m), 7.59-7.60 (1H, m), 8.10-8.20 (1H, m).
The thus obtained N,9-bis(ethoxycarbonyl-N-phenyl-1-amino-1,2,3,4-tetrahydro-9H-carbazole-3-carboxylic acid methyl ester was dissolved in methanol (10 ml), to which sodium methoxide (1 g in 28% methanol solution) was added. After stirring at room temperature for 2 hours, water was added to the reaction mixture and methanol was distilled off. Water was then added to the residue, which was extracted with ethyl acetate. After washing the liquid extract with an aqueous solution of sodium chloride, it was dried over sodium sulfate. The solvent was distilled off and the residue was submitted to silica gel column chromatography, eluting with a developing solvent of hexane/ethyl acetate=5/1. A fraction containing the desired product was concentrated by distilling off the solvent, to obtain 80 mg (yield: 59.7% from imine) of 9-ethoxycarbonyl-1,2-dihydro-9H-carbazole-3-carboxylic acid methyl ester. 1 H-NMR spectra (chemical shift, ppm: in CDCl 3 ): 1.12-1.35 (3H, m), 2.43-2.68 (3H, m), 2.79-2.90 (1H, m), 3.75 (3H, s), 4.18-4.31 (2H, m), 6.77-6.89 (2H, m), 7.25-7.35 (1H, m), 7.58-7.65 (1H, d, J=6.7 Hz), 7.77 (1H, s).
Example 13
3-methylthiophene-2-aldehydimine (1 g, 5 mmol), dimethyl malonate (3.6 g, 25 mmol) and diisopropyl ethyl amine (1.28 g, 10 mmol) were mixed in toluene (4 ml) and stirred at 80° C.. Ethyl chloroformate (1.07 g, 10 mmol) was added to the mixture. After completing the addition, the reaction mixture was heated for one hour under reflux and allowed to cool to room temperature. Water was added and the mixture was extracted with toluene. The organic layer was washed with an aqueous solution of sodium chloride and dried over sodium sulfate. The solvent was distilled off to obtain crude product of N-ethoxycarbonyl-N-phenyl-7-amino-4,5,6,7-tetrahydrobenzo[b]thiophene-5,6-dicarboxylic acid dimethyl ester. Silica gel column chromatography using a developing solution of hexane/ethyl acetate=3/1, gave a fraction containing the desired product, which was concentrated by distilling off the solvent, to obtain 1.2 g (yield: 57.7% from imine) of N-ethoxycarbonyl-N-phenyl-7-amino-4,5,6,7-tetrahydrobenzo[b]thiophene-5,6-dicarboxylic acid dimethyl ester. 1 H-NMR spectra (chemical shift, ppm: In CDCl 3 ): 0.90-1.30 (3H, m), 1.58-2.73 (joined 2H, m), 2.80-3.25 (2H, m), 3.50-3.80 (6H, m), 3.90-4.30 (2H, m), 5.10-6.30 (joined 1H, m), 6.60-6.95 (2H, m), 7.10-7.60 (5H, m).
The thus obtained N-ethoxycarbonyl-N-phenyl-7-amino-4,5,6,7-tetrahydrobenzo[b]thiophene-5,6-dicarboxylic acid dimethyl ester was dissolved in methanol (10 ml), to which sodium methoxide (1 g in 28% methanol solution) was added and stirred at room temperature for 2 hours. After adding water to the reaction mixture and distilling off methanol, water was added to the residue, which was extracted with ethyl acetate. The liquid extract was washed with an aqueous solution of sodium chloride and then dried over sodium sulfate. The solvent was distilled off and the residue submitted to silica gel column chromatography. Elution with a developing solvent of hexane/ethyl acetate=3/1 gave a fraction containing the desired product, which was concentrated by distilling off the solvent, to obtain 0.6 g (yield: 47.5% from imine) of 4,5-dihydrobenzo[b]thiophene-5,6-dicarboxylic acid dimethyl ester. 1 H-NMR spectra (chemical shift, ppm: in CDCl 3 ): 2.90-3.10 (1H, m), 3.40-3.58 (1H, m), 3.63 (3H, s), 3.83 (3H, m), 3.85-4.00 (1H, m), 6.85-6.98 (1H, d, J=4.9 Hz) , 7.27-7.40 (1H, d, J=4.9 Hz), 7.67 (1H, s).
Example 14
3-methylthiophene-2-aldehydimine (1 g, 5 mmol), acrylonitrile (1.35 g, 25 mmol) and diisopropyl ethyl amine (1.28 g, 10 mmol) were mixed in toluene (4 ml) and stirred at 80° C. Ethyl chloroformate (1.07 g, 10 mmol) was added to the mixture. After completing the addition, the reaction mixture was heated for one hour under reflux and then allowed to cool to room temperature. Water was added and the mixture extracted with toluene. The organic layer was washed with an aqueous solution of sodium chloride and then dried over sodium sulfate. The solvent was distilled off to obtain crude products of N-ethoxycarbonyl-N-phenyl-7-amino-4,5,6,7-tetrahydrobenzo[b]thiophene-6-nitrile. The resultant residue was purified by recrystallization (ethyl acetate/hexane) to obtain 0.65 g (yield: 40.0% from imine) of N-ethoxycarbonyl-N-phenyl-7-amino-4,5,6,7-tetrahydrobenzo[b]thiophene-6-nitrile. 1 H-NMR spectra (chemical shift, ppm: in CDCl 3 ): 1.00-1.30 (4H, m), 1.60 (1H, s), 1.70-1.89 (1H, m), 2.31-2.60 (2H, m), 3.11-3.27 (1H, m), 4.00-4.36 (2H, m), 6.25 (1H, s), 6.62-6.75 (1H, m), 6.90-7.11 (2H, s), 7.12-7.38 (3H, m).
The thus obtained N-ethoxycarbonyl-N-phenyl-7-amino-4,5,6,7-tetrahydrobenzo[b]thiophene-6-nitrile (100 mg) was dissolved in methanol (10 ml), to which sodium methoxide (1 g in 28% methanol solution) was added and stirred at 60° C. for 2 hours. Water was then added to the reaction mixture and, after distilling off the methanol, water was added to the residue, which was extracted with ethyl acetate. The liquid extract was washed with an aqueous solution of sodium chloride and then dried over sodium sulfate. The solvent was distilled off and the residue submitted to silica gel column chromatography. Elution with a developing solvent of hexane/ethyl acetate=3/1 gave a fraction containing the desired product, which was concentrated by distilling off the solvent, to obtain 40 mg (yield: 32.0% from imine) of 4,5,-dihydrobenzo[b]thiophene-6-nitrile. 1 H-NMR spectra (chemical shift, ppm: in CDCl 3 ): 2.49-2.70 (2H, m), 2.74-3.00 (2H, m), 6.80-6.95 (1H, m), 7.16 (1H, s), 7.27-7.41 (1H, m).
Example 15
3-methylthiophene-2-aldehydimine (1 g, 5 mmol), methyl vinyl ketone (1.75 g, 25 mmol) and diisopropyl ethyl amine (1.28 g, 10 mmol) were mixed in toluene (4 ml) and stirred at 80° C. Ethyl chloroformate (1.07 g, 10 mmol) was added to the mixture. After completing the addition, the reaction mixture was heated for one hour under reflux and then allowed to cool to room temperature. Water was added and the mixture was extracted with toluene and washed with an aqueous solution of sodium chloride and dried over sodium sulfate. The solvent was distilled off to obtain crude products of N-ethoxycarbonyl-N-phenyl-7-amino-4,5,6,7tetrahydrobenzo[b]thiophene-6-acetyl. The resultant residue was purified by recrystallization (ethyl acetate/hexane) to obtain 0.70 g (yield: 40% from imine) of N-ethoxycarbonyl-N-phenyl-7-amino-4,5,6,7-tetrahydrobenzo[b]thiophene-6-acetyl- 1 H-NMR spectra (chemical shift, ppm: in CDCl 3 ): 0.85-1.35 (4H, m), 1.50-1.90 (2H, m), 2.05-2.60 (4H, m), 2.90-3.08 (1H, m), 3.95-4.28 (2H, m), 5.90-6.77 (joined 3H, m), 6.90-7.31 (joined 5H, m).
The thus obtained N-ethoxycarbonyl-N-phenyl-7-amino-4,5,6,7-tetrahydrobenzo[b]thiophene-6-acetyl (100 mg) was dissolved in methanol (10 ml), to which sodium methoxide (1 g in 28% methanol solution) was added and stirred at room temperature for one hour. Water was then added to the reaction mixture, methanol was distilled off. Water was then added to the residue, which was extracted with ethyl acetate. The liquid extract was washed with an aqueous solution of sodium chloride and dried over sodium sulfate. The solvent was distilled off and the residue was submitted to silica gel column chromatography. Elution with a developing solvent of hexane/ethyl acetate=10/1 gave a fraction containing the desired product which was concentrated by distilling off the solvent, to obtain 40 mg (yield: 31.2% from imine) of 4,5-dihydrobenzo[b]thiophene-6-acetyl. 1 H-NMR spectra (chemical shift, ppm: in CDCl 3 ): 2.31 (3H, m), 2.40-2.85 (joined 4H, m), 6.71 (1H, m), 6.75-6.89 (1H, m), 6.90-7.01 (1H, m).
Example 16
3-methylfuran-2-carboxaldehyde (10 g, 0.09 mol) was mixed with hexane (40 ml), to which aniline (9.6 ml, 0.11 mol) was added and stirred at room temperature for 30 minutes. The reaction mixture was concentrated by distilling off the solvent and then submitted to silica gel column chromatography. Elution with a developing solvent of hexane/ethyl acetate=20/1 gave a fraction containing the desired product which was concentrated by distilling off the solvent, to obtain 5.2 g (yield: 31%) of 3-methylfuran-2-carboxaldehyde imine. 1 H-NMR spectra (chemical shift, ppm: in CDCl 3 ): 2.32 (3H, s), 6.63 (1H, d, J=4.9 Hz), 7.05-7.25 (3H), 7.26-7.40 (3H), 8.32 (1H, s).
3-methylfuran-2-carboxaldehyde imine (1.5 g, 8.15 mmol), methyl acrylate (3.5 g, 40.7 mmol) and diisopropyl ethyl amine (2.1 g, 16.3 mmol) were mixed in toluene (6 ml) and stirred at 80° C. Ethyl chloroformate (1.77 g, 16.3 mmol) was added to the mixture. After completing the addition, the reaction mixture was heated for one hour under reflux and allowed to cool to room temperature. Water was added and the mixture was extracted with toluene. The organic layer was washed with an aqueous solution of sodium chloride and dried over sodium sulfate. The solvent was distilled off to obtain crude products of N-ethoxycarbonyl-N-phenyl-7-amino-4,5,6,7-tetrahydrobenzo[b]furan-6-carboxylic acid methyl ester. Silica gel column chromatography using a developing solvent of hexane/ethyl acetate=5/1, gave a fraction containing the desired product, which was concentrated by distilling off the solvent, to obtain 1.2 g (yield: 43.0% from imine) of N-ethoxycarbonyl-N-phenyl-7-amino-4,5,6,7tetrahydrobenzo[b]furan-6-carboxylic acid methyl ester. 1 H-NMR spectra (chemical shift, ppm: in CDCl 3 ): 1.00-1.40 (3H, m), 1.65-2.10 (2H, m), 2.15-3.05 (joined 2H, m), 3.74 (3H, s), 3.95-4.30 (3H, m), 5.75-6.20 (joined 1H, m), 6.50-6.95 (2H, m), 7.00-7.50 (5H, m).
The thus obtained N-ethoxycarbonyl-N-phenyl-7-amino-4,5,6,7-tetrahydrobenzo[b]furan-6-carboxylic acid methyl ester was dissolved in methanol (10 ml), to which sodium methoxide (1 g in 28% methanol solution) was added. After stirring at 60° C. for 2 hours, water was added to the reaction mixture and methanol was distilled off. Water was then added to the residue, which was extracted with ethyl acetate. After washing the liquid extract with an aqueous solution of sodium chloride, it was dried over sodium sulfate. The solvent was distilled off and the residue was submitted to silica gel column chromatography. Elution with a developing solution of hexane/ethyl acetate=9/1 gave a fraction containing the desired product, which was concentrated by distilling off the solvent, to obtain 0.5 g (yield: 34.7% from imine) of 4,5-dihydrobenzo[b]furan-6-carboxylic acid methyl ester. 1 H-NMR spectra (chemical shift, ppm: in CDCl 3 ): 2.51-2.80 (4H, m), 3.78 (3H, s), 6.33 (1H, s), 7.31-7.42 (2H, m).
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1-amino-2-cyclohexene compounds represented by the following formula (I): ##STR1## wherein the substituents are as defined in the specification, a process for preparing the compounds and their use as intermediates in the production of medicinal and agricultural agents is disclosed.
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RELATED PATENT DATA
This patent resulted from a divisional application of U.S. patent application Ser. No. 08/887,742, which was filed on Jul. 3, 1997.
TECHNICAL FIELD
The invention pertains to semiconductor capacitor constructions and to methods of forming semiconductor capacitor constructions. The invention is thought to have particular significance in application to methods of forming dynamic random access memory (DRAM) cell structures, to DRAM cell structures, and to integrated circuitry incorporating DRAM cell structures.
BACKGROUND OF THE INVENTION
A commonly used semiconductor memory device is a DRAM cell. A DRAM cell generally consists of a capacitor coupled through a transistor to a bitline. A semiconductor wafer fragment 10 is illustrated in FIG. 1 showing a prior art DRAM array 83 . Wafer fragment 10 comprises a semiconductive material 12 , field oxide regions 14 , and wordlines 24 and 26 . Wordlines 24 and 26 comprise a gate oxide layer 16 , a polysilicon layer 18 , a silicide layer 20 and a silicon oxide layer 22 . Silicide layer 20 comprises a refractory metal silicide, such as tungsten silicide, and polysilicon layer 18 typically comprises polysilicon doped with a conductivity enhancing dopant. Nitride spacers 30 are laterally adjacent wordlines 24 and 26 .
Electrical node locations 25 , 27 and 29 are between wordlines 24 and 26 and are electrically connected by transistor gates comprised by wordlines 24 and 26 . Node locations 25 , 27 and 29 are diffusion regions formed within semiconductive material 12 .
A borophosphosilicate glass (BPSG) layer 34 is over semiconductive material 12 and wordlines 24 and 26 . An oxide layer 32 is provided between BPSG layer 34 and material 12 . Oxide layer 32 inhibits diffusion of phosphorus from BPSG layer 34 into underlying materials.
Conductive pedestals 54 , 55 and 56 extend through BPSG layer 34 to node locations 25 , 27 and 29 , respectively. Capacitor constructions 62 and 64 contact upper surfaces of pedestals 54 and 56 , respectively. Capacitor constructions 62 and 64 comprise a storage node layer 66 , a dielectric layer 68 , and a cell plate layer 70 . Dielectric layer 68 comprises an electrically insulative layer, such as silicon nitride. Cell plate layer 70 comprises conductively doped polysilicon, and may alternatively be referred to as a cell layer 70 . Storage node layer 66 comprises conductively doped hemispherical grain (HSG) polysilicon.
A conductive bitline plug 75 contacts an upper surface of pedestal 55 . Bitline plug 75 may comprise, for example, tungsten. Together, bitline plug 75 and pedestal 55 comprise a bitline contact 77 .
A bitline 76 extends over capacitors 62 and 64 and in electrical connection with bitline contact 77 . Bitline 76 may comprise, for example, aluminum.
The capacitors 62 and 64 are electrically connected to bitline contact 77 through transistor gates comprised by wordlines 26 . A first DRAM cell 79 comprises capacitor 62 electrically connected to bitline 76 through a wordline 26 and bitline contact 77 . A second DRAM cell 81 comprises capacitor 64 electrically connected to bitline 76 through wordline a 26 and bitline contact 77 . DRAM array 83 comprises first and second DRAM cells 79 and 81 .
If capacitors 62 and 64 are inadvertently shorted together, a so-called “double bit failure” will occur. Such double bit failures can occur if a stray piece of polysilicon, or HSG polysilicon, breaks off during formation of DRAM array 83 and disadvantageously electrically connects capacitors 62 and 64 . Prior art capacitor fabrication methods employ chemical-mechanical polishing (CMP) of HSG polysilicon. HSG polysilicon pieces can break off during such CMP processes and cause double bit failures. It would be desirable to develop alternative DRAM constructions which could be formed by methods avoiding double bit failures.
SUMMARY OF THE INVENTION
The invention includes a number of methods and structures pertaining to semiconductor circuit technology, including: methods of forming DRAM memory cell constructions; methods of forming capacitor constructions; DRAM memory cell constructions; capacitor constructions; and integrated circuitry. For instance, the invention encompasses a method of forming a capacitor wherein a mass of silicon material is formed over a node location, and wherein the mass comprises exposed doped silicon and exposed undoped silicon. The method can further include substantially selectively forming rugged polysilicon from the exposed undoped silicon and not from the exposed doped silicon. Also, the method can include forming a capacitor dielectric layer and a complementary capacitor plate proximate the rugged polysilicon and doped silicon.
As another example, the invention encompasses a capacitor to having a capacitor dielectric layer intermediate a first capacitor plate and a second capacitor plate, wherein at least one of the first and second capacitor plates has a surface against the capacitor dielectric layer, and wherein said surface comprises both doped rugged polysilicon and doped non-rugged polysilicon.
BRIEF DESCRIPTION OF THE DRAWINGS
Preferred embodiments of the invention are described below with reference to the following accompanying drawings.
FIG. 1 is a schematic cross-sectional view of a semiconductor wafer fragment comprising a prior art DRAM array.
FIG. 2 is a schematic cross-sectional process view of a semiconductor wafer fragment at preliminary processing step of a processing method of the present invention.
FIG. 3 is a view of the FIG. 2 wafer fragment at a processing step subsequent to that of FIG. 2 .
FIG. 4 is a view of the FIG. 2 wafer fragment at a processing step subsequent to that of FIG. 3 .
FIG. 5 is a view of the FIG. 2 wafer fragment at a processing step subsequent to that of FIG. 4 .
FIG. 6 is a view of the FIG. 2 wafer fragment at a processing step subsequent to that of FIG. 5 .
FIG. 7 is a view of the FIG. 2 wafer fragment at a processing step subsequent to that of FIG. 6 .
FIG. 8 is a view of the FIG. 2 wafer fragment at a processing step subsequent to that of FIG. 7 .
FIG. 9 is a top view of the FIG. 8 wafer fragment.
FIG. 10 is a view of the FIG. 2 wafer fragment at a processing step subsequent to that of FIG. 8 .
FIG. 11 is a view of the FIG. 2 wafer fragment at a processing step subsequent to that of FIG. 10 .
FIG. 12 is a view of the FIG. 2 wafer fragment at a processing step subsequent to that of FIG. 11 .
FIG. 13 is a view of the FIG. 2 wafer fragment at a processing step subsequent to that of FIG. 12 .
FIG. 14 is a view of the FIG. 2 wafer fragment at a processing step subsequent to that of FIG. 6 processed according to a second embodiment of the present invention.
FIG. 15 is a view of the FIG. 2 wafer fragment at a step subsequent to that of FIG. 14 .
FIG. 16 is a top view of the FIG. 15 wafer fragment.
FIG. 17 is a view of the FIG. 2 wafer fragment at a step subsequent to that of FIG. 15 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
This disclosure of the invention is submitted in furtherance of the constitutional purposes of the U.S. Patent Laws “to promote the progress of science and useful arts” (Article 1, Section 8).
Methods of forming DRAM arrays of the present invention are described with reference to FIGS. 2-17, with FIGS. 2-13 pertaining to a first embodiment of the invention, and FIGS. 14-17 pertaining to a second embodiment of the invention. In describing the first embodiment of the present invention, like numerals from the preceding discussion of the prior art are utilized where appropriate, with differences being indicated by the suffix “a” or with different numerals.
Referring to FIG. 2, a semiconductor wafer fragment 10 a is illustrated at a preliminary step of a process of the present invention. Wafer fragment 10 a comprises a semiconductive material 12 a , field oxide regions 14 a , and a thin gate oxide layer 16 a . Over gate oxide layer 16 a is formed polysilicon layer 18 a , silicide layer 20 a and silicon oxide layer 22 a . Silicide layer 20 a comprises a refractory metal silicide, such as tungsten silicide, and polysilicon layer 18 a typically comprises polysilicon doped with a conductivity enhancing dopant. Layers 16 a, 18 a , 20 a and 22 a can be formed by conventional methods.
Referring next to FIG. 3, polysilicon layer 18 a , silicide layer 20 a and silicon oxide layer 22 a are etched to form wordlines 24 a and 26 a. Such etching can be accomplished by conventional methods. Between wordlines 24 a and 26 a are defined electrical node locations 25 a , 27 a and 29 a , with wordlines 26 a comprising transistor gates which electrically connect node locations 25 a , 27 a , and 29 a . Node locations 25 a , 27 a and 29 a are diffusion regions formed within semiconductive material 12 a.
Referring to FIGS. 4 and 5, a nitride layer 28 a is provided over wordlines 24 a and 26 a and subsequently etched to form nitride spacers 30 a laterally adjacent wordlines 24 a and 26 a.
Referring to FIG. 6, an insulative material layer 34 a is formed over material 12 a and over wordlines 24 a and 26 a . Insulative layer 34 a may comprise, for example, BPSG, and can be formed by conventional methods. Insulative layer 34 a comprises an upper surface 35 a. Openings 38 a , 39 a and 40 a are formed extending through insulative layer 34 a to node locations 25 a , 27 a and 29 a , respectively.
Referring to FIG. 7, an undoped silicon layer 100 is formed over insulative layer 34 a and within openings 38 a , 39 a and 40 a . Undoped silicon layer 100 narrows openings 38 a , 39 a and 40 a , but does not fill such openings. Undoped silicon layer 100 preferably has a thickness of from about 50 Angstroms to about 1000 Angstroms, with a thickness of about 300 Angstroms being most preferred. Undoped silicon layer 100 preferably comprises substantially amorphous silicon. Such substantially amorphous layer can be 5-10% crystalline. Undoped silicon layer 100 can be formed by conventional methods, such as, for example, by deposition utilizing either silane or disilane. For purposes of the continuing discussion, and for interpreting the claims that follow, “undoped” silicon is defined as silicon having a dopant concentration of less than 5×10 18 atoms/cm 3 , and “doped” silicon is defined as silicon having a dopant concentration of at least 5×10 18 atoms/cm 3 . “Undoped” silicon preferably comprises less than or equal to 1×10 18 atoms/cm 3 , and “doped” silicon preferably comprises at least 1×10 19 atoms/cm 3 .
A doped silicon layer 102 is formed over undoped silicon layer 100 and within openings 38 a , 39 a and 40 a . In the shown embodiment of the invention, doped layer 102 completely fills openings 38 a , 39 a and 40 a . However, in alternative embodiments of the invention, such as the embodiment discussed below with reference to FIGS. 14-17, layer 102 can only partially fill openings 38 a , 39 a and 40 a. As will be appreciated by persons of ordinary skill in the art, the thickness of layer 102 will vary depending on whether layer 102 is chosen to completely fill openings 38 a , 39 a and 40 a , or to partially fill such openings. Doped silicon layer 102 preferably comprises doped polysilicon, and can be formed by conventional methods.
After formation of layers 100 and 102 , an upper surface of wafer fragment 10 a is planarized to remove layers 100 and 102 from over insulative layer 34 a . Such planarization can be accomplished by, for example, chemical-mechanical polishing (CMP).
Referring to FIG. 8, after the above-discussed planarization, pedestals 104 , 106 and 108 remain in openings 38 a , 39 a and 40 a (shown in FIG. 7 ), respectively. Pedestals 104 , 106 and 108 comprise undoped silicon layer 100 and doped silicon layer 102 , and are over node locations 25 a , 27 a and 29 a , respectively. Pedestals 104 , 106 and 108 also comprise exposed upper surfaces 116 , 118 and 120 , respectively.
FIG. 9 illustrates a top view of the FIG. 8 wafer fragment, and shows that pedestals 104 , 106 and 108 actually comprise a core of doped silicon layer 102 surrounded by undoped silicon layer 100 .
Referring again to FIG. 8, insulative layer 34 a is selectively removed relative to the silicon of pedestals 104 , 106 and 108 to form a new upper surface 37 a lower than previous upper surface 35 a (shown in FIG. 7 ). The preferred BPSG insulative layer 34 a can be selectively removed relative to pedestals 104 , 106 and 108 using a conventional oxide etch. The selective removal of insulative layer 34 a exposes a sidewall surface 110 of pedestal 104 , a sidewall surface 112 of pedestal 106 , and a sidewall surface 114 of pedestal 108 . Sidewall surfaces 110 , 112 and 114 comprise undoped silicon layer 100 . Additionally, in the shown embodiment a portion of undoped silicon layer 100 is below upper surface 37 a of BPSG layer 34 a , and remains unexposed. The depth of removal of insulative layer 34 a can be controlled by a number of methods. For example, layer 34 a could be removed via a timed etch. As another example, an etch stop layer could be formed within layer 34 a at a desired depth of surface 37 a . An example of a layer 34 a comprising an etch stop layer is a layer comprising BPSG and having a silicon nitride etch stop layer formed within the BPSG at a level of upper surface 37 a.
As exposed side wall surfaces 110 , 112 and 114 of pedestals 104 , 106 and 108 comprise undoped silicon layer 100 , and as exposed upper surfaces 116 , 118 and 120 of the pedestals comprise exposed doped silicon layer 102 , as well as exposed undoped silicon layer 100 , the pedestals comprise exposed doped silicon and exposed undoped silicon at the processing step of FIG. 8 .
Referring to FIG. 10, a rugged polysilicon layer 122 is substantially selectively formed from the exposed undoped silicon of surfaces 110 , 112 114 , 116 , 118 , and 120 (shown in FIG. 8 ), and not from the exposed doped silicon of surfaces 116 , 118 and 120 . Rugged polysilicon layer 122 comprises materials selected from the group consisting of HSG and cylindrical grain polysilicon. The substantially selective formation of a preferred HSG polysilicon layer 122 from undoped silicon surfaces but not from doped silicon surfaces can be accomplished by the following process.
First, wafer fragment 10 a is loaded into a conventional chemical vapor deposition (CVD) furnace and is subjected to an in situ hydrofluoric acid (HF) clean to remove native oxide. The in situ HF clean preferably comprises a flow rate of 85 standard cubic centimeters per minute (sccm) of HF gas and 8500 sccm of H 2 O gas, at a pressure of 15 Torr, for a time of about 20 seconds. Wafer fragment 10 a is then exposed to silane to form amorphous silicon seeds on the undoped silicon. Wafer fragment 10 a is then annealed for approximately 20 minutes at about 560° C. The seeding and anneal steps convert undoped amorphous silicon into rugged polysilicon (such as hemispherical grain polysilicon), while leaving exposed doped silicon layers not converted to rugged polysilicon. It is noted that the above-described process for forming HSG polysilicon does not require disilane, and hence is different than the “pure” selective hemispherical grain deposition utilized in high vacuum tools with disilane.
After the formation of rugged polysilicon layer 122 , a short polysilicon etch is performed to remove any monolayers of silicon deposited on insulative layer 34 a during the above-described seeding step. Such polysilicon etch can be accomplished with conventional conditions, and may comprise either a wet etch or a dry etch.
The above-described process for forming rugged polysilicon layer 122 advantageously avoids formation of polysilicon on a back side (not shown) of wafer fragment 10 a . The method can also avoid double bit failures by removing monolayers of silicon after formation of HSG.
Subsequent thermal processing of pedestals 104 , 106 and 108 can out-diffuse dopant from doped polysilicon layer 102 into undoped silicon layer 100 (shown in FIG. 8 ), to convert unexposed portions of undoped silicon layer 100 into a doped polysilicon layer 119 . Subsequent thermal processing can also out-diffuse dopant from doped polysilicon layer 102 into rugged polysilicon layer 122 . Thermal processing to out-diffuse dopant from doped polysilicon layer 102 into adjacent undoped layers will typically comprise temperatures of 800° C. or greater.
Referring to FIG. 11, a dielectric layer 124 is provided over insulative layer 34 a and over pedestals 104 , 106 and 108 . Dielectric layer 124 will typically comprise silicon nitride and or silicon oxide, although other suitable materials are known to persons of skill in the art. A capacitor cell plate layer 126 is provided over dielectric layer 124 . Capacitor cell plate layer 126 will typically comprise doped polysilicon, but other suitable materials are known to persons of skill in the art.
Referring to FIG. 12, a patterned masking layer 128 is formed over pedestals 104 and 108 , leaving pedestal 106 exposed. Subsequently, wafer fragment 10 a is subjected to etching conditions which remove cell plate layer 126 and dielectric layer 124 from proximate pedestal 106 . After such etching, pedestal 106 is electrically isolated from pedestals 104 and 108 , with the only remaining electrical connection between pedestal 106 and pedestals 104 and 108 being through wordlines 26 a . Methods for removing cell plate layer 126 and dielectric layer 124 from proximate pedestal 106 are known to persons of ordinary skill in the art.
Referring to FIG. 13, masking layer 128 is removed and an insulative layer 130 is formed over pedestals 104 , 106 and 108 , and over insulative layer 34 a . Insulative layer 130 may comprise, for example, BPSG, and can be formed by conventional methods. A conductive bitline plug 75 a is formed extending through insulative layer 130 and in electrical contact with pedestal 106 . Pedestal 106 comprises rugged lateral surfaces 136 and an upper surface 118 which has a predominant portion not comprising rugged-polysilicon. As shown, the non-rugged polysilicon of upper surface advantageously provides a smooth landing region for bitline plug 75 a.
Pedestal 106 and bitline plug 75 a together form a bitline contact 77 a . A bitline 76 a is formed over bitline plug 75 a and in an electrical connection with pedestal 106 through bitline plug 75 a. Bitline 76 a and bitline plug 75 a may be formed by conventional methods.
The above-describe method can be used to avoid chemical-mechanical polishing of a rugged polysilicon layer, thus avoiding a potential source of double bit failures.
FIG. 13 illustrates a DRAM array 83 a of the present invention. DRAM array 83 a comprises capacitors 62 a and 64 a . Capacitors 62 a and 64 a comprise capacitor storage nodes 132 and 134 , respectively, which comprise doped polysilicon layer 102 , doped polysilicon layer 119 and rugged-polysilicon layer 122 . As the doped polysilicon layer 119 is formed from the undoped silicon layer 100 (shown in FIG. 8 ), the undoped silicon layer 100 and doped silicon layer 102 of pedestals 104 and 108 in FIG. 8 together define capacitor storage nodes 132 and 134 . Storage nodes 132 and 134 have rugged-polysilicon-comprising lateral surfaces 138 and 140 , respectively. Storage nodes 132 and 134 further comprise top surfaces 116 and 120 , respectively, which have predominant portions which do not comprise rugged-polysilicon.
Cell plate layer 126 and dielectric layer 124 are operatively proximate to storage nodes 132 and 134 so that the storage nodes, together with cell plate layer 126 and dielectric layer 124 , form operative capacitors 62 a and 64 a . Dielectric layer 124 contacts rugged surfaces 138 and 140 , as well as top surfaces 116 and 120 of storage nodes 132 and 134 .
Capacitors 62 a and 64 a are connected to pedestal 106 through wordlines 26 a . Capacitor 62 a , together with bitline contact 77 a and an interconnecting wordline 26 a , comprises a first DRAM cell 79 a. Capacitor 64 a , together with bitline contact 77 a and an interconnecting wordline 26 a , comprises a second DRAM cell 81 a.
A second embodiment of the invention is described with reference to FIGS. 14-17. In describing the embodiment of FIGS. 14-17, numbering similar to that utilized above for describing the embodiment of FIGS. 2-13 is utilized, with differences being indicated by the suffix “b”, or by different numbers.
Referring to FIG. 14, a wafer fragment 10 b is shown at a processing step subsequent to that of the above-discussed FIG. 6 . Wafer fragment 10 b comprises wordlines 24 b and 26 b having constructions identical to that discussed above with regard to the prior art. Wafer fragment 10 b further comprises node locations 25 b , 27 b and 29 b between wordlines 24 b and 26 b . Wafer fragment 10 b also comprises a semiconductor substrate 12 b and field oxide regions 14 b formed over substrate 12 b.
An insulative material layer 34 b is formed over wordlines 24 b and 26 b , and over semiconductive material 12 b . Insulative layer 34 b may comprise a number of materials known to persons of ordinary skill in the art, including BPSG. Openings 38 b , 39 b and 40 b extend through insulative layer 34 b to node locations 25 b , 27 b and 29 b , respectively.
A first undoped silicon layer 146 extends over insulative layer 34 b and within openings 38 b , 39 b and 40 b . Undoped silicon layer 146 preferably comprises amorphous silicon, and preferably has a thickness of from about 50 Angstroms to about 500 Angstroms. Undoped silicon layer 146 can be formed by conventional methods, such as CVD. Undoped silicon layer 146 narrows openings 38 b , 39 b and 40 b.
A doped silicon layer 148 is formed over undoped silicon layer 146 and within narrowed openings 38 b , 39 b and 40 b . Doped silicon layer 148 preferably comprises polysilicon, and can be formed by conventional methods, such as CVD. Doped silicon layer 148 preferably has a thickness of from about 50 Angstroms to about 500 Angstroms, and preferably does not fill openings 38 b , 39 b and 40 b . Rather, doped silicon layer 148 preferably further narrows openings 38 b , 39 b and 40 b beyond where openings 38 b , 39 b and 40 b were narrowed by undoped silicon layer 146 .
A second undoped silicon layer 150 is formed over doped silicon layer 148 and within openings 38 b , 39 b and 40 b . Undoped silicon layer 150 preferably comprises the same preferable materials of first undoped silicon layer 146 . Accordingly, second undoped silicon layer 150 preferably comprises substantially amorphous silicon. Second undoped silicon layer 150 preferably has a thickness of from 50 to 500 Angstroms, and in the shown preferred embodiment does not fill openings 38 b , 39 b and 40 b.
After formation of layers 146 , 148 and 150 , wafer fragment 10 b is planarized to remove layers 146 , 148 and 150 from over insulative layer 34 b . Such planarizing may be accomplished by, for example, chemical-mechanical polishing. After the planarization of wafer fragment 10 b , pedestals 104 b , 106 b and 108 b (shown in FIG. 15) having upper surfaces 116 b , 118 b and 120 b (shown in FIG. 15 ), respectively, remain within openings 38 b , 39 b and 40 b.
Referring to FIG. 15, the material of insulative layer 34 b is selectively removed relative to the silicon of pedestals 104 b , 106 b and 108 b to form an upper surface 37 b of insulative layer 34 b which is below upper surfaces 116 b , 118 b and 120 b of pedestals 104 b , 106 b and 108 b . The removal of insulative layer 34 b exposes sidewalls 110 b, 112 b and 114 b of pedestals 104 b , 106 b and 108 b , respectively. The exposed sidewalls 110 b , 112 b and 114 b comprise first undoped silicon layer 146 . Additionally, in the shown embodiment a portion of undoped silicon layer 146 is below upper surface 37 b of BPSG layer 34 b , and remains unexposed. In the shown preferred embodiment, pedestals 104 b, 106 b and 108 b comprise hollow interiors corresponding to openings 38 b , 39 b and 40 b (shown in FIG. 14 ). The depth of removal of insulative layer 34 b can be controlled by methods such as those discussed above with reference to FIG. 8 for controlling the depth of removal of insulative layer 34 a.
Referring to FIG. 16, which is a top view of the FIG. 15 wafer fragment, second undoped silicon layer 150 lines the hollow interiors corresponding to openings 38 b , 39 b and 40 b.
Referring to FIG. 17, wafer fragment 10 b is subjected to processing identical to that discussed above regarding FIG. 10 to convert exposed undoped silicon surfaces to rugged-polysilicon surfaces, while not roughening exposed doped silicon surfaces. Such treatment forms a rugged-polysilicon layer 122 b from exposed portions of first undoped silicon layer 146 (shown in FIG. 15) and forms a rugged-polysilicon layer 160 from second undoped silicon layer 150 within the interiors of pedestals 104 b , 106 b and 108 b . Such processing also out-diffuses dopant from doped silicon layer 148 into adjacent undoped layers and thus converts unexposed portions of undoped layer 146 (shown in FIG. 15) into doped regions 119 b.
Subsequent processing, similar to the processing discussed above with reference to FIGS. 11-13, may be conducted to form a DRAM array from pedestals 104 b , 106 b and 108 b . In such DRAM array, pedestals 104 b and 108 b would be storage nodes for first and second capacitors, respectively, and pedestal 106 b would form a conductive contact to a bitline. Such subsequent processing is not illustrated as the description above regarding FIGS. 11-13 is sufficient to enable a person of skill in the art to form a DRAM array from the structure of FIG. 17 . It is noted, however, that the storage nodes formed from pedestals 104 b and 108 b would differ from the storage nodes of FIG. 13 in that the storage nodes formed from pedestals 104 b and 108 b would have the shape of upwardly open containers, with the interiors of such containers being lined by rugged-polysilicon layer 160 .
The above-described DRAMs and capacitors of the present invention can be implemented into monolithic integrated circuitry, including microprocessors.
To aid in interpretation of the claims that follow, the term “semiconductive substrate” is defined to mean any construction comprising semiconductive material, including, but not limited to, bulk semiconductive materials such as a semiconductive wafer (either alone or in assemblies comprising other materials thereon), and semiconductive material layers (either alone or in assemblies comprising other materials). The term “substrate” refers to any supporting structure, including, but not limited to, the semiconductive substrates described above.
In compliance with the statute, the invention has been described in language more or less specific as to structural and methodical features. It is to be understood, however, that the invention is not limited to the specific features shown and described, since the means herein disclosed comprise preferred forms of putting the invention into effect. The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims appropriately interpreted in accordance with the doctrine of equivalents.
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The invention includes a number of methods and structures pertaining to semiconductor circuit technology, including: methods of forming DRAM memory cell constructions; methods of forming capacitor constructions; DRAM memory cell constructions; capacitor constructions; and monolithic integrated circuitry. The invention includes a method of forming a capacitor comprising the following steps: a) forming a mass of silicon material over a node location, the mass comprising exposed doped silicon and exposed undoped silicon; b) substantially selectively forming rugged polysilicon from the exposed undoped silicon and not from the exposed doped silicon; and c) forming a capacitor dielectric layer and a complementary capacitor plate proximate the rugged polysilicon and doped silicon. The invention also includes a capacitor comprising: a) a first capacitor plate; b) a second capacitor plate; c) a capacitor dielectric layer intermediate the first and second capacitor plates; and d) at least one of the first and second capacitor plates comprising a surface against the capacitor dielectric layer and wherein said surface comprises both doped rugged polysilicon and doped nonrugged polysilicon.
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This application is a division of our U.S. Patent application Ser. No. 729,517, filed Oct. 4, 1976, now U.S. Pat. No. 4,117,943.
BACKGROUND OF THE INVENTION
Automatic numerical controlled machines are used to perform a variety of machining operations, such as milling, boring, drilling, reaming, honing, and threading. For each such operation, the exact location, the amount of material to be removed, the finished dimension, and the diameter and depth of holes to be machined, are predetermined and translated into a numerical code which is stored on magnetic tape, perforated tape, cards or the like. The machine is thus "numerically controlled" to perform many machining operations automatically without the requirement for human operators in constant attendance. Such a sequence of operations normally requires the use of a variety of tools, and so the selection of the specific tool needed for each operation and its insertion in the machine spindle is accomplished by numeric control of an automatic tool changer. The automatic tool changer selects a specific tool from a plurality of different types and sizes of tools in a storage magazine and transfers the selected tool to the spindle of the machine while simultaneously removing the previously used tool from the spindle and depositing it in the storage magazine in the position from which the newly selected tool was removed. Such a tool changing operation requires significantly less time to effect a tool change than a system which removes a tool from the spindle and searches for the position in the storage magazine from which the tool was removed and then searches the magazine for the next tool and subsequently inserts the tool in the spindle. This latter operation employs "position coding" of the magazine, whereas the instant operation employs "tool coding" which allows an old tool to be placed in the storage position from which the new tool has just been removed. It is conceivable that after a number of machine sequential operations a specific tool may have occupied every position in the tool storage magazine, without ever having impaired the machine's ability to find that tool when it is next needed.
One of the tool coding techniques currently in use employs a plurality of axially spaced lands and grooves, which may be binary coded, on each of the tool holders for facilitating the selection of a particular tool from a plurality of different types and sizes of tools. The lands and grooves are provided by a plurality of rings which are slipped over the outside diameter of the tool holder. Usually two sizes of rings are utilized, each having the same inside diameter to slidably fit the tool holder, each having the same thickness, and differing only in outside diameter, the smaller diameter ring serving as the groove, and the larger diameter ring serving as the land. These lands and grooves function as the two numerals "0" and "1" in the binary numbering system. Various combinations of grooves and lands produce binary numbers 1, 2, 4, 8 and 16 depending on their relative position along the tool holder and, therefore, require the shop man to be familiar with the binary numbering system or to use a code card to compare against the tool in order to know the cumulative value of the binary digits comprising the coded number. This has been the cause for confusion and error among machine shop personnel, both in setting up such tools and in subsequent indentification of the tool in usage. Additionally, there has been some difficulty experienced by personnel in the mounting of tools in their tool holders to the precise dimensional requirements of a fully automated numerical control system.
SUMMARY OF THE INVENTION
It is therefore an object of this invention to provide a device and method for coding and identifying machine tools which overcome the above noted problems.
A further object of this invention is to precisely locate the cutting tool within the tool holder and torque the tool holder collet to the prescribed preload while maintaining the free tool length.
Another object is to provide a system for automatically selecting, installing and inspecting tool holders having binary coding rings of improved accuracy.
The above objects, and others, are accomplished in accordance with this invention by a three-station arrangement for selecting, installing and inspecting tool holder coding rings. At the first station, binary coding rings having two different diameters (representing binary 0 and 1) are automatically selected and stacked in response to a numerical keyboard input to produce the desired binary total. At the second station, the rings are installed on a tool holder, the tool holder collet is tightened and the tool dimensions are measured and verified as within the selected tolerances. At the third station, a digital ring counter automatically inspects the ring and land configuration and produces a digital readout which can be verified against the number used in selecting the rings originally.
BRIEF DESCRIPTION OF THE DRAWING
Details of the invention, and a preferred embodiment thereof, are further described in the drawing, wherein:
FIG. 1 is a perspective view of the overall assembly comprising three sequential operating stations;
FIG. 2 is a perspective view, partially cut away showing a typical prior art tool holder useful with the system of this invention;
FIG. 3(a) is a representation of a binary coding chart for selecting coding rings;
FIG. 3(b) is schematic representation illustrating the coding of a typical tool holder;
FIG. 4 is a plan view of the coding ring selector station;
FIG. 5 is an electrical schematic diagram of the circuit used in ring selection;
FIG. 6 is a perspective view, showing the tool holder torquing station;
FIG. 7 is a plan view of the tool holder torquing device;
FIG. 8 is a vertical section through the torquing device, taken on line 8--8 in FIG. 7;
FIG. 9 is a simplified schematic diagram of the electro-pneumatic system which operates the torquing station;
FIG. 10 is a vertical elevation view showing the tool inspection assembly;
FIG. 11 is a plan view of the system control panel;
FIG. 12 is a perspective view of the ring decoder switch head used at the ring counter station;
FIG. 13 is a partial sectional view taken through one switch assembly, on line 13--13 in FIG. 12; and
FIGS. 14a and 14b are simplified electrical schematic drawings showing the ring counter circuit.
DETAILED DESCRIPTION OF THE INVENTION
Referring now to FIG. 1, there is seen an overall perspective view of the device for pre-setting tools to be used in numerical controlled machines. The components of the system are installed on a convenient work surface, such as desk-like support 10. Desk 10 may typically include drawers 12 in which parts, adjusting tools, etc. may be conveniently stored. A sloping rack 14 may be provided for storage of tool holders awaiting use.
Three sequential work stations are located on the surface of desk 10. From left to right as seen in FIG. 1, there are coding ring selector assembly 16, tool installing and dimensional measuring assembly 18 and digital ring counter assembly 20.
As detailed below, the desired digital tool code is entered at keyboard 22, causing selection of different diameter rings in the required order by ring selector 16. The resulting ring stack is installed on a conventional tool holder (typically of the type illustrated in FIG. 2). A tool is inserted, or may previously been inserted, in the tool holder. The tool holder is placed in the torquing device 24 of the installation and measuring station, the tool holder collet is tightened and vertical probe 26 and horizontal probe 28 measure tool dimensions, which are displayed on display 30.
The tool holder is then moved to the digital ring counter 20 where the number corresponding to the binary ring code produced by the pattern of rings on the tool holder is displayed. If the rings were correctly selected, the number displayed by counter 20 will be the same as that entered on keyboard 22 to start the sequence of operations.
Thus, tools for numerical controlled machines can be rapidly and accurately assembled and checked for correct coding and tool dimensions.
In order to fully comprehend the operation of this system, the configuration of a typical tool holder useful with this device should be made clear. Such a prior-art tool holder is shown, partially cut-away, in FIG. 2.
The main body 34 of tool holder 36 has a generally cylindrical exterior configuration adapted to fit conventional numerically controlled machines, such as milling machines. A pair of opposed flats 37 on tool holder 36 permit it to be secured against rotation, as detailed below. A tapered collet 38 fits into a correspondingly tapered base 40 within main body 34. A selected machining tool 42, typically a milling tool, fits within collet 38 and is retained in place when hexagonal nut 44 is tightened, driving collet 38 into bore 40. At the inner end of tool 42 a plug 46 threaded into internal threads 48 abuts tool 42. A slot 50 in the end of plug 46 permits adjustment of the extension of tool 42 by moving plug 46 thereagainst with a screwdriver prior to tightening nut 44.
A threaded securing ring 52 and flange 54 are located on main body 34 in a spaced relationship. A stack of coding rings 56 having two outside diameters are arranged in a selected sequence between securing ring 52 and flange 54, and are held in place by ring 52. The selected indentification of rings 56 can be read by sensors in the numerical control machine so that selection of the required tool according to a binary code is accomplished. While a specific tool is illustrated in FIG. 2, any other tool using rings of two different diameters for binary coding can be used with our pre-setting device.
A typical binary coding arrangement is illustrated in FIGS. 3(a) and 3(b). The chart 58 shown in FIG. 3(a) includes coding for a group of tools and for a specific tool within a group. The number down the sides of the charts, which correspond to key numbers on keyboard 22, are each the sum of the binary numbers shown by rings in the positions illustrated by dots 59. Spacers occupy positions without dots. In order to code a tool holder, one might select group 5 and tool 20, as shown by arrows 61. The use of this chart is illustrated in FIG. 3(b) in which chart 58 has been cut off just below the selected Group 5, Tool 20, locations. When the chart is placed against tool holder 36, it is seen that rings 74 correspond to chart positions containing dots 59, while spacers 76 correspond to chart positions without dots. The binary summing of the ring portions to provide chart and keyboard numbers is schematically illustrated just below tool holder 36.
Clearly mistakes are possible when a machine operator must determine ring and spacer positions from two different locations on a chart such as that shown in FIG. 3(a), then manually select and stack the rings and spacers on a tool holder. Checking ring and spacer location is difficult, since in practice the operator must refer back to the full chart and cannot cut it off for use as a gage as we have done for schematic illustration purposes in FIG. 3(b).
A plan view of ring selector 16 is shown in FIG. 4. Selector 16 includes an elevated mounting panel 60 within which the electronic components shown in FIG. 5 may be contained. Two axial drive means 62 and 64 are mounted on panel 60 with their axially movable shafts 66 and 68, respectively, lying just above the plane of panel 60. Drive means 62 and 64 may typically be electrical solenoids or hydraulic cylinders capable of moving shafts 66 and 68 rapidly between extended (as shown with shaft 66) and retracted (as shown by shaft 68) positions. Pushers 70 and 72, having a circular front surface resembling a shuffleboard cue, are secured to the ends of shafts 66 and 68, respectively. Stacks of rings 74 and spacers 76 are positioned within housings 78 and 80 adjacent to the retracted positions of pushers 70 and 72, respectively. While all of rings 74 and spacers 76 have the same inside diameter, rings 74 have a uniform larger outside diameter than the uniform smaller outside diameter of spacers 76.
When one of drive means 62 and 64 is actuated, shaft 66 or 68 is extending, pushing the bottom most ring out from under the corresponding stack. As the ring is propelled over the edge of panel 60, it falls onto an upstanding elliptical or conical member 82. Thus, when drive means 62 and 64 are pulsed in a selective sequence, a stack of rings having the selected pattern of outside diameters will be placed on upstanding member 82. As seen in FIG. 3, pusher 70 has just deposited a spacer 76 on member 82 and is retracting.
In order to produce a ring stack on member 82 having the proper binary coded indentification, the operator depresses keys on keyboard 22 in the proper order. An error may be retracted by pressing "clear" key 84. When the proper key sequence has been entered, the "install" key 86 is depressed. Drive means 62 and 64 are then electronically pulsed in the proper sequence to produce the desired ring stack.
A typical electronic circuit capable of pulsing drive means 62 and 64 in a sequence corresponding to a number entered on keyboard 22 is schematically illustrated in FIG. 4.
Each of the keys in keyboard 22 actuates a correspondingly numbered switch 90 which includes an electromagnetic means 92 for holding an operated key switch closed until cleared. If an error is made, pressing the "clear" key 84 operates normally closed clear switch 94, actuating clear relay 96, releasing all holding means 92.
Once the selected keys have all been pressed, the "install" key 86 is pressed, closing install switch 98, starting stepping motor 100. As ring selector switch 102 and spacer selector switch 104 are stepped around counter-clockwise together, the moving contact closes circuits at positions 1-8 sequentially. The first 5 contacts on switches 102 and 104 correspond to binary 1, 2, 4, 8 and 16 as shown on the chart in FIG. 3(a). Thus, if Group 5 has been selected on keyboard 22, the desired pattern will be ring, spacer ring, spacer, spacer. When ring selector switch reaches the first contact 106, the circuit is closed through switch "05" to ring install relay 108 which actuates the ring installing drive means 64 (which may be a solenoid) to push a ring 74 onto member 82. Spacer install relay 110 is not actuated, since the circuit between it and the first contact of spacer selector switch 104 was broken when normally closed switch 112 was opened when switch "05" was closed by pressing key "05".
Stepping motor 100 then steps switches 102 and 104 to the second contact. Since the circuit between contact 116 of ring selector switch 102 and the ring install relay 108 is not completed by closing switch "05", a ring is not selected. On the other hand, since closing switch "05" does not open normally closed switch 114, a circuit is complete from contact 118 of spacer selector switch to spacer install relay 110. This actuates a solenoid or other drive means 62 to push a spacer 76 onto member 82 (as seen in FIG. 4).
In a similar manner, the switches 102 and 104 are stepped through the remaining contacts. The first five contacts operate the ring or spacer selection relays, while the sixth contact on switches 102 and 104 is not used. A "clear signal" switch 120 is coupled to switches 102 and 104 for rotation therewith. When switch 120 reaches contact 122, "clear" relay 96 is actuated, clearing the keyboard and stopping stepping motor 100, by opening "install" switch 98 through release of holding means 124. A plurality of transistor diodes 126 are provided in circuits leading away from switches 102 and 104 to prevent signal path reversal.
After installation of the "Group" rings and spacers, the "Tool" rings and spacers are similarly installed. To produce the pattern shown in FIG. 3(b) key 20 on keyboard 22 would be pressed, closing switch 20 shown in FIG. 5. This will open and close the appropriate switches to provide the required spacer, spacer, ring, spacer, ring pattern.
Thus it can be seen that the ring selector 16 as shown in FIG. 4, together with electrical circuitry of the sort illustrated in FIG. 5 provides a means for rapidly and accurately selecting rings and spacers to give a desired tool holder indentification. Of course, other electrical circuits may be used, if desired. For example, electronic components can be substituted for many of the electro-mechanical arrangements shown.
The stack of coding rings and spacers 56 is lifted off of member 82 and slipped over a tool holder 36, after which retaining ring 52 is threaded into place. A corresponding tool 42 is inserted into collet 38 and plug 46 is adjusted to provide the desired tool extension, producing an assembled tool as seen in FIG. 2, ready for tool position checking and tightening of collet 38 to lock tool 42 in place.
Details of the torque head which secures the tool 42 in tool holder 36 are shown in FIGS. 6, 7 and 8. The torquing device 24 basically includes a cylindrical sleeve 134 and an outwardly extending flange 136. Sleeve 134 has a cylindrical bore 132 adapted to hold tool holder 36. Flange 136 is secured to the surface of desk 10; or, if desired to a stabilizing support column 138 (as seen in FIG. 1) which may extend through desk 10 from flange 136 to the floor. Bore 132, which continues down through the top of desk 10. If a support column 138 is provided, an opening (not shown) is provided just below the desk top at the front of column 138, so that the operator may reach into column 138 and rotates plug 46 within tool holder 36 with a screwdriver while the tool holder is mounted in the torque head. Thus, the extension of tool 42 may be adjusted while extension readings are being taken, as discussed in detail below. A setscrew 137 is brought into engagement with tool holder 36 so that the tool holder is not raised when plug 46 is adjusted with a screwdriver extended upwardly in bore 132.
A rotatable member 140 surrounds sleeve 134 and is mounted on bearings 142 and 144 for rotation relative thereto. An outwardly extending flange 146 on member 140 terminates in gear teeth which may engage a driven gear driven by any suitable conventional means, such as an electrical or air motor (not shown) mounted below the surface of desk 10.
Tool holder 36 rests in a horizontal slot 148 in the upper end of sleeve 134, which engages flats 37 on tool holder 36 (shown in FIG. 2) to hold tool holder 36 against rotation. Tool holder 36 can be secured in bore 132 by tightening setscrew 137.
A support member 150 is securely fastened to rotatable member 140, such as by cap screw 152 and pin 154. A T-slot 156 at the top of member 150 guides a wrench 158 for sliding movement toward and away from tool holder 36 within sleeve 134. To torque nut 44 to tighten collet 38 around tool 42, an operator slides wrench 158 inwardly to fully engage nut 44, then actuates the drive means to rotate rotatable member 140 by pressing button 180 on control panel 178 (FIG. 9). In a conventional manner, rotation is continued until nut 44 has been tightened to the desired torque loading.
A simplified electro-hydraulic schematic diagram illustrating the torque head operating arrangement, is shown in FIG. 9. This system uses an air motor 210 driving gear 146 through gear 212 (FIG. 1) to provide 0 to 150 foot-pounds torque at the torque head 24. Typical air motors include the Gardner-Denver Co. Series 70B4 air motors. Although air motors are preferred for simplicity and efficiency, an electric motor drive system could be used, if desired.
In the system shown in FIG. 9, shop air (or air from any source, such as a portable compressor) at a pressure of about 80 to 100 psi enters through line 214 and passes through filter 216 which removes dirt and moisture from the air. Line 214 divides, with air passing to solenoid valve 218 through line 220 and to a pressure regulator assembly 222 through line 224. Pressure regulator assembly 222 includes air dome regulator 226, preset regulator 228 and pressure gage 230. Preset regulator 228, typically a Grove Model 18 from Grove Valve and Regulator Co., presets the static load on air dome regulator 226, which may typically be a Grove Model GS400 or GH400 regulator. Pressure gage 230 measures the pressure in the dome of air dome regulator 226. This assembly 222, using the air dome loading principle, is preferred over spring types since it provides a universal control range without requiring mechanical spring adjustment and is more accurate.
Air at the selected maximum pressure passes from pressure regulator assembly 222 to a motor stop and air dump valve 232. With handle 234 in the position shown, air is directed to motor direction valve 236 through line 238. When handle 234 is moved downwardly as indicated by the arrow, air supply from line 224 is shut off and air in line 238 is dumped through exhaust 240.
With handle 242 of direction valve 236 in the position shown, air is directed to the forward drive connection of air motor 210 through line 243. An air pressure gage 244 can be calibrated in pounds torque, since the torque generated by air motor 210 is directly proportional to entering air pressure. To reverse air motor 210, handle 242 is moved downwardly as indicated by the arrow. Air in line 243 is dumped through exhaust 246 and air from line 238 is directed to the reverse connection of air motor 210 through line 248.
If it is necessary to provide greater torque than is provided by the pressure regulated line 224, additional pressure may be provided by pressing button 180 to open valve 218 to admit unregulated air through line 220 to valve 236. Ordinarily the button is quickly pressed, or "jogged" so that torque, as shown on gage 244, rises in small increments. A relief valve 250 is set to release below the pressure at which the air motor or other components might be damaged.
In use, a tool holder is placed in torque device 24 and wrench 158 is moved into engagement with nut 44. Valve handles 234 and 242 are moved to the upper, or forward drive, positions. Gear 212 (FIG. 1) is rotated by air motor 210, rotating geared flange 146 and wrench 158 (FIG. 6) to tighten nut 44. If additional torque is required, button 180 is jogged to slowly increase torque to the level desired, as indicated on gage 244. Valve handle 234 is moved to the lower or exhaust position, releasing the torque. Wrench 158 is retracted and the tool holder can be removed.
If an error was made in locating the tool 42 in tool holder 36 as indicated by vertical probe 26 or horizontal probe 28 (FIG. 1) or for any other reason, it may be desirable to remove nut 44. To do so, wrench 158 is again brought into engagement with nut 44, handle 234 is moved to the upper or operate position and handle 242 is moved to the lower or reverse position. Since the regulated air pressure is usually insufficient to break nut 44 loose, button 180 is ordinarily pressed and held down, admitting full pressure air to air motor 210, until nut 44 breaks loose. Button 180 is released and handle 234 is moved to the lower or exhaust position. Then, geared flange 146 can easily be rotated by hand during further removal of nut 44, readjustment of the tool position, etc.
While tool holder 36 is in the torquing device, the tool 42 can be checked for proper length and diameter. The inspection assembly, comprising vertical probe 26 and horizontal probe 28, is shown in FIGS. 1 and 10.
A column 164, mounted on desk 10 supports both vertical probe 26 and horizontal probe 28. If desired for greater stability, column 164 could extend through desk 10 to the floor, similarly to column 138. Vertical probe 26 includes a cylinder 166 within which measuring probe 168 is axially movable. Vertical probe 26 may be an hydraulic cylinder, lead screw or any other means allowing selective extension of measuring probe 168. Measurements are made by measuring means 170, such as a Kodar II measuring system from Ideal Aerosmith, Inc., which measures the extension of measuring probe 168. Vertical probe 26 is mounted on a carriage 172 which surrounds the upper portion of column 164 for movement therealong. Pinion gears (not shown) rotatable by knob 174 move carriage 172 along rack gear 176. Ordinarily, carriage 172 will be left in one position during measuring similar tools. When tools of greatly varying length are to be measured, carriage 172 is moved as necessary. Either an automatic compensation is made in measuring means 170 to compensate for carriage movement, or measuring means 170 is recalibrated.
After the tool has been locked in the collet by operating torque head 24 (by pressing button 180 on the control panel 178, FIG. 11) the vertical dimension, or extension, of the tool is measured by pressing vertical probe button 182 (FIG. 10) with slide switch 184 in the upper or "extension" position. While button 182 is held down, probe 168 is extended and the extension measurement from measuring means 170 is displayed on display 30, which also shows the word "extension" as seen at 31 in FIG. 1. If desired, a conventional printer may also be actuated to produce a paper copy of the exterior readout.
Measurement of the horizontal dimension of tool 42, or runout, is obtained by a horizontal probe assembly 28, which includes an hydraulic or similar cylinder 188 housing an extendable measuring probe 190. A measuring means 192, such as another Kodar II Unit, measures the extension of probe 190 and sends a signal to display 30. Horizontal probe assembly 28 is mounted on a carriage 194 which surrounds column 164 for vertical movement therealong. Carriage 194 is moved by a motor (not shown) mounted on carriage 194, which may be a conventional air or electrical motor, which drives a pinion gear (not shown) engaging rack 176 secured to column 164. This reversible motor is operated by pressing either "up" button 202 or "down" button 204 on control panel 178 (FIG. 11) to position probe 190 at the desired location. The horizontal dimension, or runout, of tool 42 is measured at the selected location by pressing horizontal probe button 206 with slide switch 184 in the lower or "runout" position. Probe 190 extends into contact with tool 42 and measuring means 192 displays the runout on display 30 while the word "runout" is also displayed. Again, if desired, a conventional printer may be used to produce a hand copy readout. When button 206 is released, probe 190 retracts. If either extension or runout is out of tolerance, nut 44 is backed off, the position of tool 42 is adjusted, nut 44 is retightened and the measurements are repeated. Runout readings may be taken at several positions by withdrawing wrench 158 and manually rotating tool holder 36 while taking other horizontal readings.
When measurement of tool 42 runout and extension is completed, the tool holder 36 is removed from torque device 24 and moved to the ring counter 20. As seen in FIG. 1, ring counter 20 includes a housing having a ledge 280 upon which tool holder 36 may be placed as shown. On the front panel of ring counter are included an "on-off" switch 282 and a digital readout display 284. The portion of tool holder 36 carrying coding rings 56 fits within a ring sensor head 286 which is shown in greater detail in FIGS. 12 and 13.
Sensor head 286 includes a base plate 288 spaced from an upper plate 290 by a pair of blocks 292 and 294. Base plate 288 has a slot 296 sized to allow tool holder 36 to slide easily but snugly thereinto. Upper plate 290 is generally U-shaped to allow placement of tool holder 36 without hindrance. Each of blocks 292 and 294 has a plurality of holes through which pins 298 protrude. The pins are aligned with ring positions on tool holder 36, with block 292 matching the 1, 3, 5, 7 etc. ring positions and pins (hidden in FIG. 12) in block 294 matching the 2, 4, 6, 8, etc. ring positions. While all pins could be located in one block, this staggered arrangement is preferred because typical micro switches are considerably thicker than coding rings 56.
Pins 298 are arranged to be slidable inwardly of the holes in the blocks. When a larger diameter ring 74 is at a selected location, the corresponding pin 288 will be pressed inwardly, while the pin will not be moved if a smaller diameter spacer ring 76 is at that location. As seen in FIG. 13, each pin 298 when moved inwardly operates a conventional microswitch 300. Microswitches 300 are held in place by long bolts 302 which pass through upper plate 290, microswitches 300, spacer blocks 304 into threaded holes in base plate 288. Similar bolts 306 secure blocks 292 and 294 to base plate 288 and upper plate 290.
Depending upon which pins 298 are engaged by large diameter code rings 74, a pattern of switches 300 will be closed which will generate a signal producing a digital output at display 284 (FIG. 1). A typical circuit for accomplishing this is shown schematically in FIGS. 14(a) and 14(b). The circuits shown in FIGS. 14(a) and 14(b) include five of the ten switches, producing output on two of the four digital readout elements, the "units" and "tens" elements, making up display 284. FIG. 14(a) includes an illustration of the ring selector switch arrangement 330, nandgate assembly circuit 352 and the "units" digital readout element 334. FIG. 14(b) ring selector switch arrangement 330 (repeated for clarity) a nandgate assembly circuit 336 and the "tens" digital readout element 338. Similar circuitry, not shown for clarity continues in the same manner to operate the "units" and "tens" display elements for the other half of the ring and spacer coding assembly.
Referring now to FIG. 14(a), the array of ring selector switches 330 which could, for example, be the top four switches 300 in FIG. 12 is seen with switch 340 closed by a ring 74 and switches 342, 344, and 346 remaining open due to the presence at the corresponding position in ring counter 20 of spacer 76 rather than rings 74. As indicated in the binary ring value column 350, for the example given, the signal from switch 340 is "1" or low (grounded) while the signals from switches 342, 344, 346 and 348 are 2, 4, 8, and 16, respectively or all high (ungrounded).
In a conventional manner, conductors connect each of the switch outputs to the correspondingly coded inputs of the individual nandgates making up nandgate array 352. For example, a "low" signal will pass from the 1 output of switch 340 to the input of each nandgate 352 having an "1" input. One of these conductors is schematically indicated at 341, illustrating a connection between the 1 contact of switch 340 and the 1 input of one of the members of nandgate array 352. Similarly, "high" signals will pass from the outputs 2, 4, 8 and 16 of the other switches to the corresponding inputs of nandgates 352. "Low" can be thought of as presence of an electrical signal while "high" is the absence of an electrical signal. Since each of nandgates 352 is an inverter, if all inputs to a nandgate are high, the nandgate output will be low, while if any of the parallel input signals is low, the nandgate output will be high.
Signals from the nandgate horizontal rows within array 352 are passed to nandgate array 354. Again, each of nandgates 354 acts as an inverter, so that if all of the input signals are high, the output will be low, while if any of the input signals are low, the output will be high.
The output signals from nandgate array 354 are inverted by inverter array 356 and conducted to digital readout element 334 in a conventional manner. Each "high" input into an inverter 356 will produce a "low" output, causing the corresponding bar elements of readout 334 to be illuminated. Thus in the present example, bars 358 and 360 will be illuminated, producing the "1" readout. The matrix of inputs to nandgates 352 are selected in a conventional manner so that the appropriate 2, 3 or more readout bars will be illuminated in the desired configuration. These may, of course be varied, depending upon the readout element configuration, number of bars, etc.
The "tens" display is operated in a similar manner, as illustrated in FIG. 13(b). In this case, for example, the second and fourth coding rings may have operated switches 342 and 346. The outputs of switches 340 through 348 are then 1 (high), 2 (low), 4 (high), 8 (low) and 16 (high). This produces a binary "10", which should appear in the digital readout elements 334 and 338. The output signals of each switch are conducted to the correspondingly coded inputs of all nandgates in nandgate array 352 (FIG. 13(a)) and 362 (FIG. 13(b)). Since the highest displayed number desired is less than 40, there are only nandgate groups in array 362 for 10, 20, and 30, as indicated in the drawing.
As discussed above, the nandgates in arrays 352 and 362 produce a low output signal when any of the parallel inputs is low. Thus, a "low" signal is produced by the nandgate rows for "0" (FIG. 14(a)) and "10" FIG. 14(b). The output signals from nandgate arrays 352 and 362 pass to nandgate arrays 354 and 364 where the signals are summed and inverted in the manner discussed above in conjunction with FIG. 14(a). The output passes to inverters 356 and 366, where the signal is inverted and directed to digital readout elements 334 and 338. "Low" signals from individual inverters in arrays 356 and 366 cause the corresponding bars of each readout to be illuminated. For the number "10", the outer ring of readout 334 is illuminated, and bars 370 and 372 of readout element 338 are illuminated.
While FIGS. 13(a) and 13(b), illustrate one decoding logic circuit, others, with other digital readout means, may be used if desired. As mentioned above, the other five decoding switches as seen in FIGS. 1 and 12, are connected to a circuit and readout means which duplicates that shown in FIGS. 13(a) and 13(b), so that all four digits are displayed.
If desired, a stack of coding rings produced at the first station may be installed on a tool holder and the coding sequence can be immediately checked at the third station prior to installation of a tool in the tool holder. While certain preferred arrangements and components are described in conjunction with the above description of a preferred embodiment, there may be varied and other components used, where suitable, with similar results. For example other electronic circuits may be substituted for those described where a similar function is performed.
Other applications, variations and ramifications of this invention will occur to those skilled in the art upon reading this disclosure. These are intended to be included within the scope of this invention, as defined in the appended claims.
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A device to code a machine tool holder, to preset the tool length, to mount the tool in the holder, and to inspect tool dimensions and coding. These functions are performed by a ring selector which selects different outside diameter rings in such sequence that a desired indentification of a tool by a combination of lands and grooves is accomplished, by a power torque machine which tightens the tool holder collet, by a digital height and diameter gage device which inspects the tool dimensions, and by a digital ring counter which gives a digital readout of the land and groove combination on the external surface of a tool holder.
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FIELD OF THE INVENTION
[0001] The present embodiments generally relate to subterranean cementing operations and, more particularly, to methods and compositions for achieving zonal isolation, controlling gas migration, preventing corrosive conditions and sustaining wellbore integrity during drilling or construction of boreholes in such subterranean formations.
BACKGROUND
[0002] The following paragraphs contain some discussion, which is illuminated by the innovations disclosed in this application, and any discussion of actual or proposed or possible approaches in this Background section does not imply that those approaches are prior art.
[0003] Natural resources such as oil and gas residing in a subterranean formation or zone are usually recovered by forming a wellbore that extends into the formation. The wellbore is drilled while circulating a drilling fluid therein. The drilling fluid is usually circulated downwardly through the interior of a drill pipe and upwardly through the annulus, which is located between the exterior of the pipe and the walls of the wellbore. After terminating the circulation of the drilling fluid, a string of pipe, e.g., casing, is run in the wellbore.
[0004] Cementing is a common technique used in wellbore operations to isolate or secure particular areas of a wellbore from other areas of a wellbore (zonal isolation). This type of cementing is typically performed by pumping a cement slurry into the annulus between the outside surface of a pipe string and the inside formation surface or wall of a wellbore and allowing the cement to set into a hard mass (i.e., sheath). Cement slurries typically contain cement, water, and various additives that can be tailored based on the type of cementing operation desired. The cement sheath attaches the string of pipe to the walls of the wellbore and seals the annulus, allowing a wellbore to be selectively completed.
[0005] However, cement can sometimes experience shrinkage that creates gaps between the cement and casing, resulting in loss of zonal isolation. Expansion additives are often added to the cement slurry in order to promote bonding integrity between the cement and the casing. Good bonding between the cement and the casing helps in achieving zonal isolation, controlling gas migration, protecting the casing from corrosive conditions and sustaining wellbore integrity. Poor bonding can limit production from the well and reduce the effectiveness of any stimulation treatments.
[0006] A large variety of materials have been used or proposed as cement expansion additives. For instance, common cement expansion additives include calcium sulfate hemihydrate, sodium sulfate and magnesium oxide. Generally, such materials provide cement expansion, however, such expansion is gained at the expense of either impaired compressive strength development or increased slurry viscosity. Furthermore, the growth of the petroleum industry has created a need for the recycling of many of the byproducts of petroleum processes. Therefore, it would be advantageous to use a petroleum process by-product as an expansion additive that provides adequate expansion, while simultaneously not affecting other desirable cement properties.
DETAILED DESCRIPTION
[0007] It is to be understood that the following disclosure provides many different embodiments, or examples, of the present invention for implementing different features of various embodiments of the present invention. Specific examples of components are described below to simplify and exemplify the present disclosure. These are, of course, merely examples and are not intended to be limiting.
[0008] According to certain embodiments of the present invention, a cement composition is provided that includes cement, water, and an expansion additive.
[0009] According to certain embodiments, the cement composition includes a hydraulic cement. According to certain embodiments, a variety of hydraulic cements may be utilized, including, but not limited to, those comprising calcium, aluminum, silicon, oxygen, iron, and/or sulfur, which set and harden by a reaction with water. Suitable hydraulic cements include, but are not limited to, Portland cements, gypsum cements, high alumina content cements, slag cements, high magnesia content cements, and combinations thereof. In certain embodiments, the hydraulic cement may comprise a Portland cement. In some embodiments, the Portland cements that are suitable for use are classified as Classes A, C, H, and G cements according to the American Petroleum Institute, API Specification for Materials and Testing for Well Cements, API Specification 10, Fifth Ed., Jul. 1, 1990.
[0010] According to certain embodiments, the cement composition includes water. The water may be fresh water, brackish water, saltwater, or any combination thereof. The cement composition may further include a water-soluble salt. Suitable water-soluble salts include sodium chloride, calcium chloride, calcium bromide, potassium chloride, potassium bromide, magnesium chloride, and combinations thereof. According to certain embodiments, the cement composition includes a water-soluble salt in an amount of from about 1% to about 36% by weight of the water (bwow). According to certain embodiments, the cement composition includes calcium chloride in an amount of from about 0.5% to about 5.0% by weight of the water (bwow).
[0011] According to certain embodiments, the expansion additive includes spent catalyst derived from oil refinery cracking processes. In oil refinery cracking, complex organic molecules such as heavy hydrocarbons are broken down into simpler molecules by the breaking of carbon-carbon bonds in the precursors. The rate of cracking and the end products are strongly dependent on the presence and type of catalysts employed. Once a catalyst has been fully utilized in the cracking process, it is described as being “spent.” Typical catalysts employed in oil refinery cracking include silica-alumina catalysts. According to certain embodiments, the expansion additive includes spent silica-alumina cracking catalyst.
[0012] In certain embodiments, the spent cracking catalyst includes active alumina, silica, phosphorous pentoxide, sulfur trioxide, calcium oxide, iron oxide, cobalt oxide, nickel oxide, molybdenum oxide, and combinations thereof. Generally, the spent cracking catalyst can be added to the cement composition in any desired concentration. According to certain embodiments, the cement composition includes spent cracking catalyst in an amount of from about 1% to about 20% by weight of cement (bwoc). In certain embodiments, the spent cracking catalyst is passed through at least a 325 mesh size sieve before use.
[0013] According to certain embodiments, the spent cracking catalyst has an aluminum oxide content of from about 65% to about 95% by weight. According to certain embodiments, the spent cracking catalyst has a silicon dioxide content of from about 1% to about 15% by weight. According to certain embodiments, the spent cracking catalyst has a diphosporous pentoxide content of from about 1% to about 10% by weight. According to certain embodiments, the spent cracking catalyst has a sulfur trioxide content of from about 1% to about 5% by weight. According to certain embodiments, the spent cracking catalyst has a calcium oxide content of from about 0.1% to about 1.0% by weight. According to certain embodiments, the spent cracking catalyst has an iron (III) oxide content of from about 2% to about 5% by weight. According to certain embodiments, the spent cracking catalyst has a cobalt oxide content of from about 0.5% to about 1.0% by weight. According to certain embodiments, the spent cracking catalyst has a nickel oxide content of from about 1% to about 3% by weight. According to certain embodiments, the spent cracking catalyst has a molybdenum oxide content of from about 5% to about 30% by weight.
[0014] According to certain embodiments, the cement composition which includes spent cracking catalyst has a percent expansion of from about 0.1% to about 10% when cured at a temperature of from about 100° F. to about 190° F. and at a pressure of from atmospheric pressure up to about 3000 psi.
[0015] According to certain embodiments, the cement composition which includes spent cracking catalyst has increased rheology but the slurry remains pourable and pumpable, and the compressive strength of the cement composition is not impaired in any way.
[0016] According to certain embodiments, the spent cracking catalyst expansion additive accelerates the thickening of the cement slurry. In certain embodiments, the cement composition which includes spent cracking catalyst attains a consistency of about 70 Bc (Bearden units of consistency) after setting for about 1 hour to about 2 hours.
[0017] According to certain embodiments, the spent cracking catalyst expansion additive has pozzolanic activity. Pozzolanic activity is a measure of the degree of reaction over time between calcium ions (or calcium hydroxide) in the presence of water. Pozzolanic activity of a composition is considered one of the parameters governing long term performance of the compressive strength of cement.
[0018] In certain other embodiments, the cement composition may further include a fluid loss additive. According to certain embodiments, the cement composition includes a fluid loss additive in an amount of from about 0.3% to about 2.0% by weight of cement (bwoc). A suitable fluid loss additive is hydroxyethyl cellulose.
[0019] In certain other embodiments, the cement composition may further include an accelerator. According to certain embodiments, the cement composition includes an accelerator in an amount of from about 1.0% to about 5.0% by weight of cement (bwoc). A suitable accelerator is calcium chloride.
[0020] In certain other embodiments, the cement composition may further include a dispersant. According to certain embodiments, the cement composition includes a dispersant in an amount of from about 0.1% to about 1.0% by weight of cement (bwoc). Suitable dispersants include polycarboxylate ether and formaldehyde sodium naphthalene sulfonate condensate.
[0021] In certain embodiments, a method for setting cement in order to reduce contraction of the cement is provided. According to certain embodiments, the method comprises first mixing water, cement and a cement expansion additive in order to form a cement slurry. In certain embodiments, a fluid loss additive can also be included in the cement slurry. The water to cement ratio can be determined based on the need for the cementing operation. One of ordinary skill in the art can determine the ratio of water to cement needed for a particular operation. According to certain embodiments, the cement expansion additive is the spent cracking catalyst composition described above.
[0022] According to certain embodiments, the cement slurry is pumped or injected into the desired place and allowed to expand and harden.
[0023] The following examples are illustrative of the compositions and methods discussed above.
EXAMPLES
Cement Slurry Preparation
[0024] Spent cracking catalyst was obtained from RKG International Pvt Ltd. and was analyzed for oxide content by X-Ray Fluorescence. The spent cracking catalyst had an oxide content as shown in Table 1 below:
[0000]
TABLE 1
Spent Cracking Catalyst Oxide Composition
Spent
Element as
cracking
Oxides
catalyst (%)
Al 2 O 3
71.31
SiO 2
6.02
P 2 O 5
4.06
SO 3
1.14
CaO
0.29
Fe 2 O 3
3.51
CO 3 O 4
0.80
NiO
1.40
MoO 3
11.48
TOTAL
100
[0025] A cement slurry containing the spent cracking catalyst was prepared by mixing 152.21 g of water, 300.0 g of Class G cement, 30.0 g of the spent cracking catalyst, 3.0 g of CaCl 2 , and 1.8 g of Halad®-322. Halad®-322 is a fluid loss additive that includes hydroxyethyl cellulose and is commercially available from Halliburton Energy Services.
[0026] A control cement slurry containing Microbond, instead of the spent cracking catalyst, was prepared by mixing 149.23 g of water, 300 g of Class G cement, 30.0 g of Microbond, 3.0 g of CaCl 2 , and 1.8 g of Halad®-322. Microbond is a gypsum blend and is commercially available from Halliburton Energy Services.
Expansion Testing
[0027] The expansion effect of the spent cracking catalyst and other cement additives was tested by pouring cement slurries into a ring expansion mold and measuring the amount of expansion exerted on the ring by each cement slurry as they set.
[0028] Five cement slurries, four with different expansion additives and one without an expansion additive, were prepared and poured into a ring expansion mold. The slurries included the ingredients indicated in Table 2 below.
[0000]
TABLE 2
CEMENT SLURRY COMPOSITIONS
Water
Class G
Expansion
CaCl 2
Halad ®-
Slurry
(g)
Cement (g)
additive (g)
(g)
322
No
150.78
300.0
0.0
3.0
1.8
expansion
additive
Fresh
150.50
300.0
30.0
3.0
1.8
catalyst
(pure
alumina)
Molybdenum
162.30
300.0
30.0
3.0
1.8
oxide
Microbond
149.23
300.0
30.0
3.0
1.8
Spent
152.21
300.0
30.0
3.0
1.8
cracking
catalyst
Percent Expansion at 100° F. and Atmospheric Pressure
[0029] The cement slurries set forth in Table 2 were prepared and poured into ring expansion molds and were then allowed to cure for 7 days at 100° F. and atmospheric pressure. After 7 days, the percent expansion of the ring expansion mold was measured. All experiments were run three times. Table 3 summarizes the results of these expansion tests.
[0000]
TABLE 3
Expansion at 100° F., atmospheric pressure
Curing
Expansion
time
% Expansion
Average
Additive
(Days)
1
2
3
Expansion (%)
No expansion
7
0.18
0.16
0.18
0.17
additive
Fresh catalyst
7
0.35
0.31
0.35
0.34
Molybdenum
7
0.23
0.24
0.24
0.24
oxide
Microbond
7
0.42
0.42
0.44
0.43
Spent cracking
7
0.60
0.62
0.62
0.61
catalyst
[0030] The cement composition prepared with the spent cracking catalyst had an average expansion of 0.61%. In contrast, the cement composition that did not include an expansion additive had an average expansion of 0.17%. Also in contrast, the cement compositions prepared with fresh catalyst, molybdenum oxide and Microbond had average expansions of only 0.34%, 0.24% and 0.43%, respectively, at the same temperature and pressure. These results show that a cement composition that includes the spent cracking catalyst provides greater expansion at 100° F. and atmospheric pressure than a cement composition with no cement expansion additive and cement compositions with that include fresh catalyst, molybdenum oxide and Microbond. These results demonstrate that it is the spent cracking catalyst and the blend of oxides included in the spent cracking catalyst that is contributing to the expansion of the cement.
Percent Expansion at 100° F. and 3000 Psi
[0031] The cement slurries set forth in Table 2 that included the spent cracking catalyst and Microbond expansion additives, were prepared and poured into ring expansion molds and were then allowed to cure for 7 days at 100° F. and 3000 psi. After 7 days, the percent expansion of the ring expansion mold was measured. All experiments were run three times. Table 4 summarizes the results of these expansion tests.
[0000]
TABLE 4
Expansion at 100° F., 3000 psi
Expansion
Curing
% Expansion
Average
Additive
time (Days)
1
2
3
Expansion (%)
Microbond
7
0.69
0.66
0.66
0.67
Spent
7
0.76
0.79
0.79
0.78
cracking
catalyst
[0032] The cement composition prepared with the spent cracking catalyst had an average expansion of 0.78%. In contrast, the cement composition prepared with Microbond had an average expansion of only 0.67% at the same temperature and pressure. This result shows that a cement composition that includes the spent cracking catalyst provides greater expansion at 100° F. and 3000 psi compared to a cement composition that includes Microbond.
Percent Expansion at 190° F. and 3000 Psi
[0033] The cement slurries set forth in Table 2 that included the spent cracking catalyst and Microbond expansion additives, were prepared and poured into ring expansion molds and were then allowed to cure for 7 days at 190° F. and 3000 psi. After 7 days, the percent expansion of the ring expansion mold was measured. All experiments were run three times. Table 5 summarizes the results of these expansion tests.
[0000]
TABLE 5
Expansion at 190° F., 3000 psi
Curing
Expansion
time
% Expansion
Average
Additive
(Days)
1
2
3
Expansion (%)
Microbond
7
0.79
0.77
0.79
0.78
Spent cracking
7
1.08
1.08
1.08
1.08
catalyst
[0034] The cement composition prepared with the spent cracking catalyst had an average expansion of 1.08% at 190° F. and 3000 psi. In contrast, the cement composition prepared with Microbond had an average expansion of only 0.78% at the same temperature and pressure. This result shows that a cement composition that includes the spent cracking catalyst provides greater expansion at 190° F. and 3000 psi compared to a cement composition that includes Microbond.
Thickening Test
[0035] The thickening of cement slurries was tested by measuring the time it took for the cement slurries to reach 70 Bc (Bearden units of consistency).
[0036] The cement slurries set forth in Table 2 that included the spent cracking catalyst and Microbond expansion additives, were prepared and were monitored with a Fann HPHT consistometer Model 290 and the time it took for the cement slurries to reach 70 Bc was measured. Table 6 summarizes the results of the thickening tests.
[0000]
TABLE 6
Thickening time at 100° F., 2600 psi
Expansion
Additive
Time (hr:min)
Bc
Microbond
2:47
70
Spent Cracking
1:49
70
Catalyst
[0037] The cement composition prepared with the spent cracking catalyst as the cement expansion additive took 1 hour and 49 minutes to reach 70 Bc, compared to a cement composition prepared with Microbond as the cement expansion additive which took 2 hours and 47 minutes to reach 70 Bc. This result shows that a cement composition that includes the spent cracking catalyst expansion additive has a much shorter thickening time to reach 70 Bc at 100° F. and 2600 psi compared to a cement composition that includes Microbond, a conventional cement expansion additive.
Compressive Strength Testing
[0038] Wellbore cement compositions develop and maintain compressive strength to withstand typical conditions experienced in a wellbore. The compressive strength of a cement composition is determined with a UCA (Ultrasonic Cement Analyzer) which determines how the compressive strength of the cement develops over time during curing (or setting). The compressive strength of a cement is determined by measuring the change in velocity of an ultrasonic signal transmitted through the cement sample as it hardens. As the compressive strength of the cement increases, the transmit time of the signal through the sample decreases. The UCA can then convert the signal transmit time into a compressive strength (psi) measurement.
[0039] The cement slurries set forth in Table 2 that included the spent cracking catalyst and Microbond expansion additives, were prepared and were tested for the time it took them to reach a compressive strength of 50 psi, and again for their compressive strength at 24 hours using a UCA device. In typical oilfield processes, cement compositions need to develop a compressive strength of at least 50 psi before commencing further drilling of a well. Therefore, the shorter the time it takes for a cement composition to reach a compressive strength of 50 psi, the more desirable that cement composition is for use in oilfield processes. Table 7 summarizes the results of the compressive strength testing.
[0000]
TABLE 7
Compressive strength at 100° F., 3000 psi
Expansion
Compressive
Additive
strength (psi)
Time (hr:min)
Microbond
50
5:01
2780
24:00
Spent cracking
50
3:37
catalyst
2183
24:00
[0040] The cement composition prepared with the spent cracking catalyst expansion additive reached a compressive strength of 50 psi in 3 hours and 37 minutes, compared to the cement composition prepared with the Microbond expansion additive which reached a compressive strength of 50 psi in 5 hours and 1 minute. Additionally, the cement composition prepared with the spent cracking catalyst reached a compressive strength of 2183 psi after 24 hours, compared to the cement composition prepared with Microbond which reached a compressive strength of 2780 psi after 24 hours. Therefore, these results show that utilizing the spent cracking catalyst as a cement expansion additive does not impair, and in face enhances, early compressive strength development of the cement composition compared to a cement composition that includes the conventional Microbond expansion additive. Also, these results show that utilizing the spent cracking catalyst as a cement expansion additive does not prevent a cement composition from attaining an acceptable compressive strength at 24 hours after cure.
Rheology Test
[0041] Two samples of the cement slurries set forth in Table 2 that included the spent cracking catalyst and Microbond expansion additives, were prepared and were analyzed using a Fann 35 rheometer with bob and sleeve arrangement, and the dial readings, which are related to viscosity, at various RPMs were recorded. The results of the rheology tests are shown in table 8 below.
[0000]
TABLE 8
Rheology Test
Spent cracking
Spent cracking
Microbond
Microbond
catalyst
catalyst
RPM
Sample 1
Sample 2
Sample 1
Sample 2
3
1
1
12
18
6
2
2
15
18
30
6
7
17
19
60
10
12
22
24
100
15
17
28
32
200
29
32
45
48
300
44
44
66
66
600
85
112
[0042] The results in Table 8 show that that cement slurries prepared with the spent cracking catalyst have comparable viscosities to those prepared with Microbond. Furthermore, the results in Table 8 are within the range that demonstrates that cement slurries prepared with the spent cracking catalyst are pourable and can be pumped easily.
[0043] While the present invention has been described in terms of certain embodiments, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the appended claims.
[0044] The present disclosure has been described relative to certain embodiments. Improvements or modifications that become apparent to persons of ordinary skill in the art only after reading this disclosure are deemed within the spirit and scope of the application. It is understood that several modifications, changes and substitutions are intended in the foregoing disclosure and in some instances some features of the invention will be employed without a corresponding use of other features. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the scope of the invention.
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A cement composition and method for well treatment employing the cement composition that is effective at achieving zonal isolation, controlling gas migration, preventing corrosive conditions and sustaining wellbore integrity during drilling or construction of boreholes in such subterranean formations. The cement composition includes spent cracking catalyst from oil cracking processes.
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This is a divisional of application(s) Ser. No. 09/195,512 filed on Nov. 19, 1998 now U.S. Pat. No. 6,069,245 which is a continuation of Ser. No. 08/832,253 filed Apr. 3, 1997 now U.S. Pat. No. 5,902,882.
TECHNICAL FIELD
The present invention is concerned with a novel process for the manufacture of azepines and with intermediates used in this process.
DETAILED DESCRIPTION
The present invention is concerned with a process for the manufacture of azepines of the formula
wherein R 1 and R 2 are independently an acyl residue of an aromatic carboxylic acid.
The compounds of formula I include known, pharmacologically active compounds, for example, balanol (see Int. Patent Application WO 93/03730) and other phosphokinase inhibitors, for example, the compounds described in European Patent Application A-0 663 393. The process in accordance with the invention enables such compounds to be manufactured in a simpler and more economical manner than has been possible with previously known processes.
In the scope of the present invention, acyl residues R 1 and R 2 are selected from the group consisting of benzoic acid; benzoic acid substituted by the group selected from hydroxy, halogen, preferably fluorine, lower-alkyl and lower-alkoxy; benzoyl; and benzoyl substituted by the group selected from fluorine, lower-alkyl and lower-alkoxy. The term “lower” denotes groups with 1-6 C atoms. Compounds of formula I in which R 2 is p-hydroxybenzoyl or p-(2-fluoro-6-hydroxy-3-methoxybenzoyl)benzoyl and R 1 is p-hydroxybenzoyl or 4-hydroxy-3,5-dimethylbenzoyl are preferred. R 4 is an amino protecting group, perferably tert.-butoxycarbonyl.
In one embodiment of the present invention, the novel process for the manufacture of compounds of formula I comprises the catalytic asymmetric hydrogenation of a compound of the formula
wherein R 3 is lower-alkyl and HX is an acid, to a compound of the formula
Examples of acids HX for the acid addition salts of formula II and formula IV are inorganic acids, such as mineral acids, for example HCl, and organic acids, such as sulphonic acids, for example, p-toluenesulphonic acid and methanesulphonic acid.
The catalyst for the asymmetric hydrogenation is a complex of an optically active, preferably atropisomeric, diphosphine ligand with a metal of Group VIII of the periodic system, especially ruthenium. Such catalysts are described, for example, in European Patent Publication A-0 643 052.
As catalysts there come into consideration rhodium-diphosphine complexes of the formulae
(RuL) 2+ (X 0 ) 2 III-a
(RuLX 2 ) 2+ (X 0 ) 2 III-b
(RuLX 1 X 2 ) + X 3 III-c and
RuL(X 4 ) 2 III-d
wherein
X 0 is selected from the group consisting of BF 4 − , ClO 4 − , B(phenyl) 4 − , SbF 6 − , PF 6 − , and Z 1 —SO 3 − ; X 1 is halide; X 2 is benzene, hexamethylbenzene or p-cymene; X 3 is selected from the group consisting of halide, ClO 4 − , B(phenyl) 4 − , SbF 6 − , PF 6 − , Z 1 —SO 3 − and BF 4 − ; X 4 is selected from the group consisting of Z 2 —COO—, Z 3 —SO 3 − , allyl and CH 3 COCH═C(CH 3 )O—; Z 1 is halogenated lower alkyl or halogenated phenyl; Z 2 is selected from the group consisting of lower alkyl, phenyl, halogenated lower alkyl and halogenated phenyl; Z 3 is lower alkyl or phenyl; and L is an optically active, preferably atropiso-meric, diphosphine ligand.
Especially preferred ligands L are
MeOBIPHEP (6,6′-Dimethoxybiphenyl-2,2′-diyl)bis-(diphenylphosphine); BIPHEMP (6,6′-Dimethylbiphenyl-2,2′-diyl)bis-(diphenylphosphine); BINAP ((1,1′-Binaphthyl)-2,2′-diyl)bis-(diphenylphosphin); pTol-BIPHEMP (6,6′-Dimethylbiphenyl-2,2′-diyl)bis(di-(p-tolyl)phosphine); pAn-MeOBIPHEP 6,6′-Dimethoxy-P,P,P′,P′-tetrakis-(4-methoxy-phenyl)-biphenyl-2,2′-bis-phosphine; pDMA-MeOBIPHEP 6,6′-Dimethoxy-P,P,P′,P′-tetrakis-(4-dimethylamino-phenyl)-biphenyl-2,2′-bis-phosphine; pPhenyl-MeOBIPHEP (6,6′-Dimethoxybiphenyl-2,2′-diyl)-bis(bis-(biphenyl)-phosphine); mTol-BIPHEMP (6,6′-Dimethylbiphenyl-2,2′-diyl)bis(di-(m-tolyl)phosphine); Cy 2 -MeOBIPHEP P2, P2-Dicyclohexyl-6,6′-dimethoxy-P2′,P2′-diphenyl-biphenyl-2,2′-bis-phosphine; 2-Furyl 2 -BIPHEMP P,P-Diphenyl-P′,P′-di-2-furyl-(6,6′-di methyl-biphenyl-2,2′-diyl)diphosphine; (3,5-Me,4-MeO)-MeOBIPHEP 6,6′-Dimethoxy-P,P,P′,P′-tetrakis-(dimethyl-4-methoxy-phenyl)-biphenyl-2,2′-bis-phosphine; DiMeOBIPHEP (5,5′,6,6′-Tetramethoxybiphenyl-2,2′-diyl)bis(diphenylphosphine); TriMeOBIPHEP (4,4′,5,5′,6,6′-Hexamethoxybiphenyl-2,2′-diyl)bis(diphenylphosphine); and 2-Furyl-MeOBIPHEP (6,6′-Dimethoxybiphenyl-2,2′-diyl)bis-(di-2-furylphosphine).
These ligands are described in Patent Publications EP 643 052, EP 647 648, EP 582 692, EP 580 336, EP 690 065, EP 643 065, JP 523 9076.
Diacetoxy-ruthenium-[(R)-6,6′-dimethoxybiphenyl-2,2′-diyl]bis(diphenylphosphine [Ru(OAc) 2 (R)-MeOBIPHEP] is an especially preferred catalyst.
The ratio of ruthenium to ligand L in the complexes of formulae II-a to III-d is from about 0.5 mol to about 2 mol, preferably at about 1 mol of ruthenium per mol of ligand. The substrate/catalyst ratio (S/C; mol/mol) is from about 20 to about 30000, preferably from about 100 to about 5000.
The hydrogenation is carried out with the exclusion of oxygen in ethanol under an elevated pressure, for example, at pressures of from about 1 bar to about 100 bar, preferably from about 5 bar to about 70 bar, and at temperatures of from about 0° C. to about 80° C., preferably from about 20° C. to about 50° C.
The compound of formula IV is converted into a carboxylic acid compound of the formula
wherein R 4 is a protecting group,
preferably a tert.-butoxycarbonyl group. The ester group R 3 of the compound of formula IV is saponified using aqueous alkali, for example, sodium hydroxide solution, at room temperature. The carboxylic acid of formula V is then converted by known methods into an acid azide or acid amide containing compound of the formula
wherein A is azide or amino.
Subsequent degradation according to Curtius or Hofmann, yields an oxazolidone compound of the formula.
The oxazolidone of formula VI is hydrolyzed to a compound having the formula
in a manner known per se, for example, using aqueous-alcoholic alkali while heating to 70-90° C.
The hydroxy group and the amino group in the compound of formula VII are then acylated in a manner known per se, for example, by reaction with a reactive derivative of a carboxylic acid R 1 COOH or R 2 COOH, such as a mixed anhydride. When these carboxylic acids contain acylatable groups, such as OH groups, these groups are conveniently intermediately protected. Compounds of formula I in which R 1 and R 2 are different from one another can be obtained, for example, by N-acylating the amino group in the compound of formula VII selectively with 1 equivalent of R 1 COOH and subsequently O-acylating with 1 equivalent of R 2 COOH.
The protecting group R 4 can be removed in a manner known per se from the compound of formula VII. For example, when R 4 is tert.-butoxycarbonyl group, R 4 can be removed by treatment with an acid, such as 2N HCl in a solvent such as ethyl acetate.
Another embodiment of the novel process for the manufacture of compounds of formula I, in accordance with the present invention, comprises microbially reducing a compound of the formula
wherein R 3 is lower alkyl and R 4 is a protecting group, to a compound having the formula
In principal, the reduction is not limited to a specific microorganism. Fungus strains (fungi), especially yeasts, are conveniently used as the microorganisms. An especially preferred microorganism is Hanseniaspora uvarum R 1052, especially the strain deposited on 16.1.1996 at the Deutschen Sammlung von Mikroorganismen und Zellkulturen (DSMZ) under No. DSM 10 496.
The reduction of a compound III to a compound of formula IV can be carried out using intact cell cultures or using enzymes obtained from the microorganisms. The preferred microorganism, Hanseniaspora uvarum R 1052, can be cultivated in aerobic aqueous submersed cultures on usual nutrient substrates which contain carbon and nitrogen sources, for example, glucose or starch, and, respectively, soya meal, yeast extract or peptone, as well as inorganic salts, such as ammonium sulphate, sodium chloride or sodium nitrate. The cultivation can be carried out at temperatures of about 20-35° C., preferably at 27° C., in a pH range of about 3-9, preferably at about pH 5-7.
The compound of formula III is added to the culture of the microorganism in an organic solvent, for example, ethyl acetate.
The course of the reduction can be followed by thin-layer chroma-tography of samples of the reaction medium. In general, the reaction takes about 8-12 hours. The reaction product, the compound of formula VIII, can be separated from the culture solution by extraction with a suitable organic solvent, for example, with ethyl acetate.
In the next reaction step, the compound of formula VIII is saponified, using aqueous alkali, for example, sodium hydroxide solution, at room temperature, to its corresponding carboxylic acid. The carboxylic acid is then converted using known methods into an acid azide or acid amide containing compound of the formula
Subsequent degradation according to Curtius or Hofmann yields an oxazolidone compound of the formula
By alkaline hydrolysis of the oxazolidone IX, for example by using aqueous-alcoholic alkali while heating to 70-90° C., there is obtained a compound of the formula
The hydroxy group and the amino group in the compound of formula X are then acylated in a manner known per se, for example, by reaction with a reactive derivative of a carboxylic acid R 1 COOH or R 2 COOH, such as a mixed anhydride. The compound of formula X is preferably N-acylated with an aromatic carboxylic acid of the formula R 1 COOH to a compound having the formula
The compound of formula XI is then acylated with an aromatic carboxylic acid or a reactive derivative thereof, of the formula R 2 OH, in the presence of triphenylphosphine and diethyl azo-dicarboxylate, to yield a compound having the formula
The protecting group R 4 can be removed in a manner known per se from the compound of formula XII. For example, when R 4 is tert.-butoxycarbonyl group, R 4 can be removed by treatment with an acid, such as 2N HCl in a solvent such as ethyl acetate.
The intermediate compounds of the formulae II, IV, V, VI, VIII, VIIIa, IX, X and XI as well as the compound prepared in Example 12a and, respectively, 17 are novel and are likewise objects of the present invention.
The invention is illustrated in more detail by the following Examples, however is in no manner limited thereby. In these Examples, the abbreviations used have the following significance: “ee” is “enantiomeric excess”, which is defined as percent of R-product minus percent of S-product; “dec.” is “decomposition”; HPLC is high performance liquid chromatography.
EXAMPLE 1
Preparation of Compounds of Formula II and Formula III.
a) A solution of 218.3 g of di-tert-butyl dicarbonate in 250 ml of dichloromethane was added at 20-25° C. while stirring, in the course of 1 hour, to 101.2 g of piperidin-3-ol in 750 ml of dichloromethane. The reaction mixture was stirred at room temperature for a further 2 hours. Thereafter, a solution of 33.6 g of sodium bicarbonate and 11.9 g of potassium bromide in 1000 ml of deionized water was added and the reaction mixture was cooled to −20 C. After the addition of 0.39 g of 2,2,6,6-tetramethyl-piperidine 1-oxide, 560 g of 13.3% aqueous sodium hypochlorite solution were added at 0-5° C. in the course of 80 minutes. After stirring at −2° C. for a further 30 minutes, the excess sodium hypochlorite solution was added at 0-5° C. in the course of 80 minutes. After stirring at −20° C. for a further 30 minutes, the excess sodium hypochlorite was destroyed by the addition of about 10 ml of 38% aqueous sodium bisulphite solution. The reaction mixture was then warmed to 20° C. and the aqueous layer was separated and extracted with 500 ml of dichloromethane. Both organic phases were washed with 500 ml of 10% sodium chloride solution, combined and dried over sodium sulphate. After filtration and removal of the solvent under reduced pressure the oily residue was purified by distillation under reduced pressure which yielded 191.2 g of tert-butyl 3-oxo-piperidine-1-carboxylate as a colourless oil, boiling point 80-82° C./0.01 mbar. b) 99.6 g of the compound obtained in paragraph a) were dissolved in 600 ml of diethyl ether. The solution was cooled to −70° C. and the white suspension was treated simultaneously and dropwise in the course of 1 hour with solutions of 62.0 ml of ethyl diazoacetate in 125 ml of diethyl ether and 69.0 ml of boron trifluoride etherate in 125 ml of diethyl ether, with the internal temperature being held at −70° C. After stirring at −70° C. for a further 1 hour the cooling bath was removed, the reaction mixture was warmed to 0° C. and treated with 375 ml of 10% sodium carbonate solution. The aqueous phase was separated and extracted with 250 ml of diethyl ether. The organic phases were washed with 250 ml of 10% sodium chloride solution, combined and dried over sodium sulphate. The solvent was removed under reduced pressure at 30° C. yielding ethyl 1-(tert-butoxycarbonyl)-4-oxo-azepan-3-carboxylate as a crude product in the form of a yellow oil, which was used in the next step without further purification. c) 147.2 g of the product obtained in paragraph b) were dissolved in 1250 ml of dioxan and seeded with 0.1 g of ethyl 4-oxo-azepan-3-carboxylate hydrobromide. Thereafter, 175 ml of 5.7M. HBr/ethyl acetate were added at room temperature, while stirring, in the course of 25 minutes. After further seeding with 0.1 g of ethyl 4-oxo-azepan-3-carboxylate hydrobromide, the suspension was stirred at room temperature for 5 hours. The crystals were filtered off, washed with ethyl acetate and dried at 50° C. and 25 mbar. The resulting 91.0 g of crude ethyl 4-oxo-azepan-3-carboxylate hydrobromide was dissolved in 1250 ml of 2-butanone while stirring and heating under reflux. The solution was cooled to 65° C. and seeded with 0.1 g of pure ethyl 4-oxo-azepan-3-carboxylate hydrochloride. After cooling to room temperature, the suspension was stirred at room temperature for 1 hour and at 0° C. for 3 hours. The crystals were filtered off, washed with 200 ml of 2-butanone (cooled to −10° C.) and dried at 50° C. and 25 mbar, yielding 68.2 g of white ethyl 4-oxo-azepan-3-carboxylate hydrobromide, melting point 127-130° C. (dec.). d) 59.4 g of the compound obtained in paragraph b) were dissolved in 1000 ml of 1M HCl in dioxan and stirred at room temperature for 24 hours. After a reaction period of 1.5 hours the solution was seeded with about 25 mg of ethyl 4-oxo-azepan-3-carboxylate hydrochloride. The white suspension was filtered, washed with dioxan and dried at 50° C. and 25 mbar, yielding 31.3 g of ethyl 4-oxo-azepan-3-carboxylate hydrochloride in the form of white crystals, which contained about 0.4 mol of dioxan per mol of hydrochloride according to the NMR spectrum. The hydrochloride was recrystallized for further purification and in order to remove the dioxan. 31.3 g of ethyl 4-oxo-azepan-3-carboxylate hydrochloride were dissolved in 600 ml of 2-butanol at 80° C. and the solution was cooled to −20° C. in the course of 2 hours and stirred at −20° C. for 3 hours. The white suspension was filtered, washed with 2-butanol (cooled to −20° C.) and dried at 50° C. and 25 mbar to yield 22.9 g of ethyl 4-oxo-azepan-3-carboxylate hydrochloride in the form of white crystals, melting point 145-148° C. (dec.).
EXAMPLE 2
75.0 g of ethyl 4-oxo-azepan-3-carboxylate hydrochloride and 800 ml of ethanol were introduced into an autoclave. The autoclave was closed and the air was removed therefrom by repeated evacuation to about 0.1 bar and pressurization with argon (7 bar) and hydrogen (40 bar) while stirring. Thereafter, a solution of 226 mg of diacetoxy-rhuthenium (R)-6,6′-dimethoxybiphenyl-2,2-diyl)-bis(diphenylphosphine) in 20 ml of ethanol was fed into the autoclave at 2 bar hydrogen pressure with the exclusion of oxygen. Thereafter, hydrogen pressure was increased to 40 bar and the reaction mixture was hydrogenated while stirring at 30° C. for 19 hours and at 50° C. for 3 hours. Thereafter, the content of the autoclave was washed out with 200 ml of ethanol and the combined solutions were evaporated at 50° C./100 mbar and the brown residue was dried for 2 hours. The residue (75.9 g, consisting of about 80% 3R,4R and 20% 3S,4R isomers) was triturated with 450 ml of tetrahydrofuran at 24° C. for 19 hours and at 16° C. for 1 hour. The crystals were filtered off under suction, washed with tetrahydrofuran and dried to constant weight at 50° C./20 mbar for 3.5 hours. There were obtained 56.3 g of light beige crystals, which were again triturated with 225 ml of tetrahydrofuran as previously described. The crystals were removed by suction filtration and dried, yielding 55.1 g of ethyl (3R,4R)-4-hydroxy-azepan-3-carboxylate hydrobromide in the form of white crystals, which were enantiomerically pure according to HPLC.
EXAMPLE 3
As in Example 2, 23.2 g of ethyl 4-oxo-azepan-3-carboxylate hydrochloride in 90 ml of ethanol were hydrogenated with a solution of 36.1 mg of the ruthenium catalyst in 10 ml of ethanol under 40 bar hydrogen pressure at 30° C. for 21 hours and at 50° C. for 3 hours. The residue, consisting of about 80% 3R,4R and 20% 3S,4R isomers, was triturated with tetrahydrofuran and ethanol at 50° C. for half an hour and at room temperature for 4 hours. The crystals were filtered off under suction, washed with a small amount of tetrahydrofuran/ethanol and dried to constant weight at 50° C./20 mbar, to yield 13.3 g of enantiomerically pure ethyl (3R,4R)-4-hydroxy-azepan-3-carboxylate hydrochloride in the form of white crystals.
EXAMPLE 4
As in Example 2, 0.44 g of ethyl 4-oxo-azepan-3-carboxylate hydrochloride in 9 ml of ethanol was hydrogenated with a solution of 3.2 mg of di(η 2 -acetato)(η 4 -cycloocta-1,5-diene)-ruthenium(II) and 5.8 mg (R)-MeOBIPHEP in 1 ml of diethyl ether/THF 3/1 under 40 bar hydrogen pressure at 25° C. for 23.5 hours. The yellow hydrogenation solution was evaporated on a rotary evaporator at 40°/20 mbar. With a conversion of 83%, the residue consisted, according to HPLC analysis, of 65% ethyl (3R,4R)-4-hydroxy-azepan-3-carboxylate hydrochloride with an ee>99%.
EXAMPLE 5
The hydrogenations set forth in Table 1 were carried out in an analogous manner to Examples 2-4.
TABLE 1
Asymmetric hydrogenation of ethyl 4-oxo-azepan-3-carboxylate.HX 1 )
Ex
T
Press.
Conv./
trans 3 )
cis
No
L
X
Solv.
° C.
bar
hr
%
ee
%
ee
5a
(S)-BINAP
Cl
2)
25
40
62/23
78
>99
22
73
5b
(R)-BIPHEMP
Cl
2)
25
40
90/23
66
94
34
38
5c
(R)-pTol-
Cl
2)
25
40
93/23
72
>99
28
62
BIPHEMP
5d
(R)-p-An-
Cl
2)
25
40
87/23
80
>99
20
77
MeOBIPHEP
5e
(R)-mTol-
Cl
2)
25
40
90/24
58
97
42
47
BIPHEMP
5f
(R)-pDMA-
Cl
2)
25
40
79/24
72
>99
28
95
MeOBIPHEP
5g
(R)-pPhenyl-
Cl
2)
25
40
54/23
82
>99
18
26
MeOBIPHEP
5h
(S)-3,5-Me,4-
Cl
2)
25
40
34/23
55
>99
45
61
MeO-MeOBIPHEP
5i
(R)-DiMeOBIPHEP
Cl
2)
25
40
99/23
66
>99
34
86
5j
(R)-MeOBIPHEP
Br
EtOH
40
100
99/21
76
>99
24
84
5k
″
Br
EtOH
60
100
100/21
69
>99
31
85
5l
(R)-2-Furyl-
Br
EtOH
40
100
76/29
64
98
36
95
MeOBIPHEP
5m
(R)-2-Furyl-2-
Br
EtOH
40
100
94/21
68
>99
32
69
Biphemp
5n
(R)-TriMeOBIPHEP
Br
EtOH
30
100
100/23
76
>99
24
95
5o
(R)-Cy2-
Cl
EtOH
80
20
100/22
38
>99
62
92
MeOBIPHEP
5p
(R)-MeOBIPHEP
Cl
MeOH
30
100
100/22
75
>99
25
88
5q
″
Cl
iPrOH
″
″
90/22
78
>99
22
84
5r
″
Cl
AcOH
25
40
97/23
5
>99
95
94
1) Catalyst preparation analogously to Example 2 and 3.
2) Catalyst preparation: in situ analogously to Example 4, solvent: ethanol-diethyl ether-tetrahydrofuran 9:0.65:0.35.
3) trans: compound IV or its enantiomer. Chiral diphosphine ligands with (R)-configuration give (3R,4R)-IV.
EXAMPLE 6
As in Example 3, 3.32 g of ethyl 4-oxo-azepan-3-carboxylate hydrochloride were hydrogenated in the presence of 6.3 mg of [RuCl((R)-MeOBIPHEP)(C6H6)]Cl under 40 bar hydrogen pressure at 30° C. for 19 hours and at 50° for 3 hours. The yellow hydrogenation solution was evaporated on a rotary evaporator at 40°/20 mbar. With a conversion of 95% the residue consisted, according to HPLC analysis, of 79% ethyl (3R,4R)-4-hydroxy-azepan-3-carboxylate with an ee>99%.
EXAMPLE 7
A catalyst solution was prepared in a glove box (O 2 content <1 ppm) by dissolving 1.3 ml of a 0.03 molar ethanolic HBr solution and 16.1 mg of Ru(OAc)2((R)-MeOBIPHEP) in 10 ml of ethanol and stirring for 0.5 hour. Then, 0.53 g of ethyl 4-oxo-azepan-3-carboxylate hydrobromide and 2 ml of the catalyst solution prepared above were placed in 4 ml of ethanol in an autoclave and hydrogenated at 20° C. under 100 bar hydrogen pressure for 21 hours. The yellow hydrogenation solution was evaporated on a rotary evaporator at 40°/20 mbar. With a conversion of 76%, the residue consisted, according to HPLC analysis, of 58% ethyl (3R,4R)-4-hydroxy-azepan-3-carboxylate hydrobromide with an ee>99%.
EXAMPLE 8
A catalyst solution was prepared in a glove box (O 2 content <1 ppm) by dissolving 1.0 ml of a 0.04 molar ethanolic HBF4 solution and 32.1 mg of Ru(OAc)2((R)-MeOBIPHEP) in 10 ml of ethanol and stirring for 0.5 hour. Then, 0.53 g of ethyl 4-oxo-azepan-3-carboxylate hydrobromide and 1 ml of the catalyst solution prepared above were placed in 9 ml of ethanol in an autoclave and hydrogenated at 20° C. under 100 bar hydrogen pressure for 21 hours. The yellow hydrogenation solution was evaporated on a rotary evaporator at 40°/20 mbar. With a conversion of 44% the residue consisted according to HPLC analysis of 37% ethyl (3R,4R)-4-hydroxy-azepan-3-carboxylate hydrobromide with an ee>99%.
EXAMPLE 9
67.0 g of ethyl (3R,4)-4-hydroxy-azepan-3-carboxylate hydrobromide were suspended in 500 ml of tert-butyl methyl ether and treated with 30.4 g of triethylamine. Thereafter, a solution of 54.6 g of di-tert-butyl dicarbonate in 25 ml of tert-butyl methyl ether was added at room temperature in the course of 20 minutes. Thereafter, the mixture was stirred at room temperature for a further 2 hours.
500 ml of 2N NaOH were added to the white suspension and the reaction mixture was stirred vigorously at room temperature for 2 hours. The reaction mixture was then acidified with 175 ml of 6N HCl and, after phase separation, the aqueous phase was extracted twice with 100 ml of tert-butyl methyl ether. All organic phases were washed with 150 ml of 10% sodium chloride solution, combined and dried over sodium sulphate. After removal of the solvent under reduced pressure at 40° C. the crude hydroxyacid was dissolved in 260 ml of butyl acetate at about 85° C. After seeding with pure product the suspension was cooled to −20° C. in the course of 2 hours and stirred at this temperature overnight. The suspension was filtered, washed with 100 ml of hexane and dried at 50° C. and 25 mbar, yielding 55.9 g of (3R,4R)-4-hydroxy-azepan-1,3-dicarboxylic acid 1-tert-butyl ester, melting point 121.5-122.5° C.
EXAMPLE 10
300 ml of ethyl acetate and 20.9 ml of triethylamine were added to 38.9 g of the compound prepared in Example 9. The solution was heated to reflux, then 32.4 ml of diphenylphosphoryl azide were added in the course of 30 minutes and the heating under reflux was continued for a further 2 hours. After cooling to room temperature the reaction mixture was treated with 300 ml of ethyl acetate and washed with 150 ml of 5% sodium hydrogen carbonate solution and twice with 150 ml of water. The aqueous phases were extracted twice with 300 ml of ethyl acetate. The combined organic phases were dried over sodium sulphate and evaporated at 45° C. under reduced pressure. The crude crystalline residue was dissolved in 300 ml of butyl acetate, seeded with pure product, cooled to −20° C. in the course of about 3 hours and stirred overnight. The suspension was filtered, washed with butyl acetate (pre-cooled to −20° C.) and dried at 60° C. and 25 mbar to yield 29.9 g of (3aR,8aR)-5-tert-butoxycarbonyl-2-oxo-octahydro-oxazolo[4,b-c]azepine, melting point 152.5-153.5° C.
EXAMPLE 11
25.6 g of the compound prepared in Example 10 were added to 250 ml of methanol and 250 ml of 2N NaOH. The reaction mixture was heated to reflux and held at this temperature for 3 hours. After cooling, 265 ml of solvent were distilled off at 50° C. and 150 mbar and the residue was extracted three times with 200 ml of ethyl acetate each time. The three organic phases were washed with 50 ml of 10% sodium chloride solution, combined and dried over sodium sulphate. After removal of the solvent the viscous oil obtained as the residue was dissolved in 100 ml of cyclohexane at 60° C., seeded with pure product, cooled to room temperature in the course of 2 hours and stirred overnight. The suspension was filtered, washed with 40 ml of cyclohexane and dried at 50° C. and 25 mbar, yielding 21.5 g of tert-butyl (3R,4R)-3-amino-4-hydroxy-azepan-1-carboxylate, melting point 99-100.5° C.
EXAMPLE 12
a) 4.58 g of p-toluenesulphonyl chloride dissolved in 24 ml of dichloromethane were added at room temperature in the course of 10 minutes to 4.66 g of 4-tert-butoxybenzoic acid and 6.11 g of 4-dimethylaminopyridine in 30 ml of dichloromethane. After stirring at room temperature for 2 hours, 2.30 g of the compound prepared in Example 6 in 6 ml of dichloromethane were added in the course of 10 minutes. Thereafter, the mixture was stirred at room temperature for 16 hours. The reaction mixture was washed twice with 20 ml of 1N NaOH each time and then with 40 ml of 1N HCl and 40 ml of water. All aqueous phases were extracted with 20 ml of dichloromethane. The combined organic phases were dried over sodium sulphate and the solvent was removed under reduced pressure. The residual white foam was chromatographed over 300 g of silica gel with 6.5 l of hexane-ethyl acetate (2:1). Fractions of 250 ml were collected. Fractions 8-25 were combined and the solvent was evaporated under reduced pressure, there being obtained 5.91 g of a white foam which was dissolved in 80 ml of heptane at 60° C. After stirring at −20° C. overnight the crystals were filtered off, washed with cold heptane and dried at 50° C. and 25 mbar to yield 5.34 g of tert-butyl (3R,4R)-3-(4-tert-butoxy-benzoylamino)-4-(4-tert-butoxy-benzoyloxy)-azepan-1-carboxylate, melting point 1 25.5-127.5° C.
b) 20.0 ml of 5M HCl in ethyl acetate were added at room temperature and while stirring to 5.83 g of the compound obtained in paragraph a) dissolved in 30 ml of ethyl acetate. The reaction mixture was stirred at room temperature overnight and the white precipitate was filtered off and washed three times with 5 ml of ethyl acetate each time and dried at 50° C./25 mbar for 16 hours. The white powder obtained was dissolved in 50 ml of water and stirred at 50° C. for 1 hour. The solution was then lyophilized and yielded 3.97 g of pure 3-(4-hydroxy-benzoylamino)-4-(4-hydroxy-benzoyloxy)-hexahydroazepine hydrochloride.
EXAMPLE 13
Hanseniaspora uvarum R 1052 was cultivated for 3 days at 27° C. in a Petri dish containing a solid nutrient substrate. After 3 days, 100 ml of liquid nutrient medium in a 500 ml shaking flask was seeded with a loop of this culture. This pre-culture was shaken at 27° C. for 18 hours. The cells grew to a density of 5×10 8 cells/ml (stationary phase). The entire pre-culture was used to inoculate a reactor which contained 7500 ml of nutrient medium (containing 1% yeast extract Difco: Bacto Yeast Extract # 0127-17-9, 1% Pepton Difco: Bacto Peptone # 0118-17-0 and 2% glucose in deionized water). After 18 hours, 750 ml of 50% glucose solution and immediately thereafter 29 g of the compound prepared in Example 1b dissolved in 20 ml of ethyl acetate were added in the course of 25 minutes. After 12 hours the culture solution was extracted twice with 2000 ml of ethyl acetate each time. The combined organic phases were dried over sodium sulphate. The solvent was removed under reduced pressure at 30° C. to yield 30.1 g of ethyl (3R,4S)-1-(tert-butoxycarbonyl)-4-hydroxy-azepan-3-carboxylate as a viscous orange oil.
EXAMPLE 14
a) A mixture of 28.7 g of the compound prepared in Example 13 in 200 ml of tert-butyl methyl ether and 200 ml of 2N NaOH was stirred vigorously at room temperature for 4 hours and then at 50° C. for 20 hours. After cooling, the aqueous phase was extracted twice with 100 ml of tert-butyl methyl ether each time. The organic phases were discarded. The aqueous phase was acidified cautiously with about 70 ml of 6N HCl and extracted once with 200 ml of tert-butyl methyl ether and twice with 100 ml of tert-butyl methyl ether each time. All three organic phases were washed once with 50 ml of 10% sodium chloride solution, combined and dried over sodium sulphate. After removal of the solvent under reduced pressure (40° C./25 mbar) the brown viscous oil was dissolved in 60 ml of isopropyl ether at 60° C. and left to crystallize at −20° C. for 16 hours. The crystals were filtered off, washed with a small amount of isopropyl ether, cooled to −20° C. and dried at 40° C. for 5 hours and 25 mbar, yielding 12.0 g of (3R,4S)-4-hydroxy-azepan-1,3-dicarboxylic acid 1-tert-butyl ester of melting point 98.5-101.5° C.
b) 140 ml of ethyl acetate, 9.8 ml of triethylamine and 15.9 ml of diphenylphosphoryl azide were added to 18.1 g of the compound obtained in paragraph a). The solution was heated to reflux for 2 hours, cooled, diluted with 140 ml of ethyl acetate and washed with 70 ml of 5% sodium hydrogen carbonate solution and twice with 70 ml of water each time. The three aqueous phases were separated and washed three times with 140 ml of ethyl acetate. The combined organic phases were dried over sodium sulphate and the solvent was removed at 45° C./25 mbar. The crude crystalline residue was dissolved in 140 ml of butyl acetate at about 80° C., seeded with pure product, cooled and stirred at −20° C. for 6 hours. The suspension was filtered, washed with butyl acetate (cooled to −20° C.) and dried at 60° C. and 25 mbar overnight, to yield 13.3 g of tert-butyl (3aR,8aS)-2-oxo-octahydro-oxazolo[4,b-c]azepine-5-carboxylate of melting point 158-159° C.
EXAMPLE 15
200 ml of methanol and 200 ml of 2N NaOH were added to 20.5 g of the compound prepared in Example 14b). The reaction mixture was heated to reflux and left at this temperature for 4 hours. After cooling, 200 ml of methanol were distilled off at 50° C. and 150 mbar and the residue was extracted three times with 160 ml of ethyl acetate each time. The organic phases were washed with 40 ml of 10% sodium chloride solution, combined and dried over sodium sulphate. After removal of the solvent, the viscous oil obtained as the residue was dissolved in 80 ml of methylcyclohexane at 50° C., seeded with pure product, cooled and stirred at 0° C. for 4 hours. The crystals were filtered off, washed with 20 ml of methylcyclohexane and dried at 50° C. and 25 mbar overnight, yielding 17.4 g of tert-butyl (3R,4S)-3-amino-4-hydroxy-azepan-1-carboxylate, melting point 64-67° C.
EXAMPLE 16
9.06 g of p-toluenesulphonyl chloride in 75 ml of dichloro-methane were added at room temperature to 11.5 g of 4-(tert-butoxy)-benzoic acid and 13.1 g of 4-dimethylaminopyridine in 100 ml of dichloromethane. The reaction mixture was stirred for a further 2 hours. The solution was then added in the course of 1 hour to 11.5 g of the compound prepared in Example 10 dissolved in 50 ml of dichloromethane. After stirring at room temperature for 1 hour, the reaction mixture was washed with 100 ml of 1N NaOH, 100 ml of 1N HCl and 100 ml of water. All aqueous phases were extracted with 50 ml of dichloromethane. The combined organic phases were dried over sodium sulphate and the solvent was separated under reduced pressure. The foam-like residue was dissolved in 400 ml of hot heptane and left to crystallize at room temperature overnight. The crystals were washed with 25 ml of heptane and dried at 50°/25 mbar to yield 17.3 g of tert-butyl (3R,4S)-3-(4-tert-butoxy-benzoylamino)-4-hydroxy-azepan-1-carboxylate of melting point 131.5-132.5° C.
EXAMPLE 17
262 mg of diethyl azadicarboxylate in 2 ml of tetrahydrofuran were added while stirring to 407 mg of the compound prepared in Example 16, 253 mg of 4-(tert-butoxy)-benzoic acid and 394 g of triphenylphosphine in 8 ml of tetrahydrofuran. After stirring at 50° C. for 4 hours, the solvent was removed under reduced pressure and the residue was taken up in 20 ml of cyclohexane and washed once with 20 ml of water and twice with 10 ml of 70% methanol/water each time. The aqueous-alcoholic phase was extracted twice with 10 ml of cyclohexane each time. The combined cyclohexane phases were dried over sodium sulphate and the solvent was removed under reduced pressure. The residual viscous oil was dissolved in 10 ml of hot heptane, seeded with pure end product and left to crystallize at room temperature for 18 hours and yielded 241 mg of tert-butyl (3R,4R)-3-(4-tert-butoxy-benzoylamino]-4-(4-tert-butoxy-benzoyloxy)-azepan-1-carboxylate of melting point 126-128° C. This compound can be reacted further as in Example 12b.
EXAMPLE 18
12.91 g of p-toluenesulphonyl chloride dissolved in 15 ml of dichloromethane were added at room temperature in the course of 15 minutes to 1.94 g of 4-(tert-butoxy)-benzoic acid and 2.63 g of 4-dimethylaminopyridine in 20 ml of dichloromethane. The reaction mixture was stirred for 2 hours and added in the course of 1 hour to 2.30 g of tert-butyl (3R,4R)-3-amino-4-hydroxy-azepan-1-carboxylate dissolved in 10 ml of dichloromethane. After stirring for 1 hour the reaction mixture was washed with 20 ml of 1N NaOH, 20 ml of 1N HCl and 20 ml of water. All aqueous phases were washed in succession with 10 ml of dichloromethane. The combined organic phases were dried over sodium sulphate, filtered and the solvent was evaporated. The foam-like residue obtained was dissolved in 80 ml of hot heptane and crystallized at room temperature overnight. The crystals were washed with 10 ml of heptane and dried to yield 3.23 g of tert-butyl (3R,4R)-3-(4-tert-butoxy-benzoylamino)-4-hydroxy-azepan-1-carboxylate, m.p. 134-135° C.
EXAMPLE 19
572 mg of p-toluenesulphonyl chloride in 3.5 ml of dichloromethane were added at room temperature in the course of 10 minutes to 679 mg of 4-benzoyl-benzoic acid and 764 mg of 4-dimethylaminopyridine in 5 ml of dichloromethane. After further stirring at room temperature for 2 hours 1016 mg of tert-butyl (3R,4R)-3-(4-tert-butoxy-benzoylamino)-4-hydroxy-azepan-1-carboxylate in 2.5 ml of dichloromethane were added in the course of 10 minutes while stirring. Thereafter, the reaction mixture was stirred at room temperature for a further 2.5 hours and washed with 6 ml of 1N NaOH, 6 ml of 1N HCl and 6 ml of water. All aqueous phases were extracted in succession with 6 ml of dichloromethane. The combined organic phases were dried over sodium sulphate and the solvent was evaporated. The crude product was chromatographed over 100 g of silica gel with 1.41 of hexane/ethyl acetate (2:1). Fractions of 100 ml were collected. Fractions 5-9 were combined and the solvent was evaporated. There were obtained 1.48 g of a white foam, which was crystallized from 50 ml of hot heptane, to yield 1.24 g of tert-butyl (3R,4R)-3-(4-tert-butoxy-benzoylamino)-4-(4-benzoyl-benzoyloxy)-azepan-1-carboxylate, m.p. 145-148° C., as a white powder.
EXAMPLE 20
3.0 ml of 5N HCl in ethyl acetate were added at room temperature while stirring to 922 mg of the azepine prepared in Example 19 in 4.0 ml of ethyl acetate. The reaction mixture was stirred at room temperature overnight and the precipitate was filtered off, washed three times with 2 ml of ethyl acetate and dried at 50° C./25 mbar for 16 hours yielding 0.70 g of 3-(4-hydroxy-benzoylamino)-4-(4-benzoyl-benzoyloxy)-hexahydroazepine hydrochloride.
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A novel process for the manufacture of compounds of the formula
wherein R 1 and R 2 independently represent aroyl.
The present invention also concerns novel intermediates used in the novel process for making compounds of formula I.
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FIELD OF THE INVENTION
[0001] This invention pertains generally to the field of charge pumps and more particularly to improving their efficiency.
BACKGROUND
[0002] Charge pumps use a switching process to provide a DC output voltage larger or lower than its DC input voltage. In general, a charge pump will have a capacitor coupled to switches between an input and an output. During one clock half cycle, the charging half cycle, the capacitor couples in parallel to the input so as to charge up to the input voltage. During a second clock cycle, the transfer half cycle, the charged capacitor couples in series with the input voltage so as to provide an output voltage twice the level of the input voltage. This process is illustrated in FIGS. 1 a and 1 b . In FIG. 1 a , the capacitor 5 is arranged in parallel with the input voltage V IN to illustrate the charging half cycle. In FIG. 1 b , the charged capacitor 5 is arranged in series with the input voltage to illustrate the transfer half cycle. As seen in FIG. 1 b , the positive terminal of the charged capacitor 5 will thus be 2* V IN with respect to ground.
[0003] Charge pumps are used in many contexts. For example, they are used as peripheral circuits on flash and other non-volatile memories to generate many of the needed operating voltages, such as programming or erase voltages, from a lower power supply voltage. A number of charge pump designs, such as conventional Dickson-type pumps, are know in the art. FIG. 2 shows a 2 stage, 2 branch version of a conventional Dickson type charge pump that receives Vcc as its input voltage on the left and generates from it an output voltage on the right. The top branch has a pair of capacitors 303 and 307 with top plates connected along the branch and bottom plates respectively connected to the non-overlapping clock signals CLK 1 and CLK 2 . The capacitors 303 and 307 are connected between the series of transistors 301 , 305 , and 309 , which are all diode connected to keep the charge from flowing back to the left. The bottom branch is constructed of transistors 311 , 315 , and 319 and capacitors 313 and 317 arranged in the same manner as the top branch, but with the clocks reversed so the two branches will alternately drive the output.
[0004] V TH -cancellation pumps can be used to replace the traditional Dickson charge pumps with diode connected switches for better efficiency and strong IV characteristics, because the V TH -drop in each stage of a Dickson charge pump is offset by boosting the gate of the transfer switch to a higher voltage through an auxiliary pump. However this kind of architecture has an inherent reverse leakage issue when the pump is supposed to deliver very high currents, such as where a large capacitance is instantaneously connected to the output of the pump. The reverse leakage issue hampers pump recovery time and causes power loss. Consequently, such V TH -cancellation pumps could benefit from ways to reduce this revers leakage problem.
SUMMARY OF THE INVENTION
[0005] According to a first set of aspects, a charge pump circuit generates an output voltage. The charge pump circuit includes an output generation section, an offset cancellation section, and first and second output transistors. The output generation section has a first leg receiving a first clock signal and providing a first output and has a second leg receiving a second clock signal and providing a second output, wherein the first and second clock signals are non-overlapping. The first and second outputs of the first and second output generation section's legs are respectively connected through the first and second output transistors to provide the output voltage. The offset cancellation section has a first leg providing a first offset cancellation output and has a second leg having a second offset cancellation output, where the first and second offset cancellation outputs of the output generation section are respectively connected to the control gate of the first and second output transistors. When the first and second offset cancellation outputs are high, the first and second outputs of the output generation section are respectively high; and when the first and second outputs of the output generation section are low, the first and second offset cancellation outputs are respectively low. The charge pump circuit also includes first and second shorting transistors. The first shorting transistor is connected between the first output of the output generation section and the control gate of the first output transistor and has a gate connected to the gate of the second output transistor. The second shorting transistor is connected between the second output of the output generation section and the control gate of the second output transistor and has a gate connected to the gate of the first output transistor.
[0006] Another set of aspects concern a method of reducing leakage in a charge pump circuit. The method includes receiving an input voltage, receiving a first clock at a first branch of a first charge pump section and generating from it a first output from the input voltage, and receiving a second clock signal at a second branch of the first charge pump section and generating from it a second output from the input voltage. The first and second clock signals are non-overlapping. The method also includes receiving a third clock at a first branch of a second charge pump section and generating therefrom a third output from the input voltage and receiving a fourth clock signal at a second branch of the second charge pump section and generating therefrom a fourth output from the input voltage. The first and second charge pump sections have the same structure. The first clock signal is high when the third clock signal is high and the third clock signal is low when the first clock signal is low. The second clock signal is high when the fourth clock signal is high and the fourth clock signal is low when the second clock signal is low. The third and fourth outputs are applied to the control gates of first and second transistors, respectively, where the first and second transistors are respectively connected between the first and second outputs of the first charge pump section and the output of the charge pump circuit. The fourth and third outputs are applied to the control gates of third and fourth transistors, respectively, wherein the third transistor is connected between the first output and the third output and the fourth transistor is connected between the second output and the fourth output.
[0007] Various aspects, advantages, features and embodiments of the present invention are included in the following description of exemplary examples thereof, which description should be taken in conjunction with the accompanying drawings. All patents, patent applications, articles, other publications, documents and things referenced herein are hereby incorporated herein by this reference in their entirety for all purposes. To the extent of any inconsistency or conflict in the definition or use of terms between any of the incorporated publications, documents or things and the present application, those of the present application shall prevail.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The various aspects and features of the present invention may be better understood by examining the following figures, in which:
[0009] FIG. 1 a is a simplified circuit diagram of the charging half cycle in a generic charge pump.
[0010] FIG. 1 b is a simplified circuit diagram of the transfer half cycle in a generic charge pump.
[0011] FIG. 2 shows a 2 stage, 2 branch version of a conventional Dickson type charge pump.
[0012] FIG. 3A is a schematic of a voltage double type of charge pump with V TH cancellation.
[0013] FIGS. 3B and 3C illustrate a clock scheme and typical node voltages for the device of FIG. 3A .
[0014] FIG. 4 shows a recovery time profile, transient response and I-V curves
[0015] FIGS. 5-7 show embodiments of V TH cancellation charge pumps having reduced reverse leakage.
[0016] FIGS. 8A and 8B illustrate voltage and current levels for the circuits of FIGS. 3A and 7 , respectively.
DETAILED DESCRIPTION
[0017] A typical doubler-based charge pump stage is shown in FIG. 3A , with a corresponding clock scheme shown in FIG. 3B . Pump capacitors C 1 401 and C 2 403 get charged through switches M 3 405 and M 4 407 , respectively, to a voltage V IN during phase Φ 2 /Φ 1 respectively. This voltage is then boosted by a voltage V DD by using clocks, Φ 1 /Φ 2 , and passed on to V OUT through switches M 1 409 / M 2 411 respectively. To minimize the drop across switches M 1 409 and M 2 411 , a higher voltage is used at nodes V G1 /V G2 , which are in turn obtained through a separate auxiliary pump using pump capacitors C B1 421 , C B2 422 and along with boosted clocks, Φ B1 /Φ B2 to boost V IN by 2V DD . Typical node voltages are shown in FIG. 3C .
[0018] A common application of a charge pump is to supply a high-voltage bias to very large capacitive load, represented C L 433 . An example of this is when the charge pump is a peripheral element of a flash EEPROM memory circuit. This load is typically switched ON (here represented by closing a switch S 1 431 ) after the charge pump reaches steady state, causing a significant voltage drop on the output V OUT . The time taken for the charge pump to reach steady-state again is termed the recovery time. Voltage doubler-based architectures suffer from a slow recovery compared to the Dickson-type architectures due to a reverse-leakage phenomenon that is absent in Dickson-type architectures.
[0019] To explain this phenomenon, consider a charge pump in steady-state. When switch M 1 409 is ON, consider a very large capacitor C L 433 connected suddenly to the node V OUT using switch S 1 431 . The pump capacitor C 1 401 loses charge instantaneously to C L 433 , causing the voltage V OUT to drop by some voltage, say V drop . This charge lost to the load should be replenished in the next phase from the supply V IN through the switch M 3 405 , during which time the switch M 1 409 should be completely OFF. Since there is no discharge path for the auxiliary pump capacitor, C B1 421 , it loses no charge and V G1 still stays at V IN , whereas V 1 has dropped to V IN −V drop . For an appreciable drop, this switch, M 1 409 , starts conducting and enables an alternate current path from the output node back into the pump capacitor, C 1 401 . This slows down the voltage build-up on V OUT as charge from C L 433 leaks back into the pump and the recovery time increases. Though the charge is not lost and goes back into the pump capacitor, switching losses in this reverse-leakage path attribute to increased power consumption during recovery. This is the reverse-leakage issue addressed in the following. A typical recovery profile for both types of charge pump is shown in FIG. 4 .
[0020] More information on prior art charge pumps, such as Dickson type pumps, and charge pumps generally, can be found, for example, in “Charge Pump Circuit Design” by Pan and Samaddar, McGraw-Hill, 2006, or “Charge Pumps: An Overview”, Pylarinos and Rogers, Department of Electrical and Computer Engineering University of Toronto, available on the webpage “www.eecg.toronto.edu/˜kphang/ece1371/chargepumps.pdf”. Further information on various other charge pump aspects and designs can be found in U.S. Pat. Nos. 5,436,587; 6,370,075; 6,556,465; 6,760,262; 6,922,096; 7,030,683; 7,554,311; 7,368,979; 7,795,952; 7,135,910; 7,973,592; and 7,969,235; US Patent Publication numbers 2009-0153230-A1; 2009-0153232-A1; 2009-0315616-A1; 2009-0322413-A1; 2009-0058506-Al; US- 2011 - 0148509 -A1; 2007-0126494-A1; 2007-0139099-A1; 2008-0307342 A1; and 2009-0058507 A1; and applications Ser. Nos. 12/973,641 and 12/973,493, both filed Dec. 20, 2010, and Ser. No. 13/228,605, filed Sep. 9, 2011. More detail on voltage cancellation pumps, including multi-stage arrangements, can be found in U.S. Pat. No. 7,969,235.
[0021] The basic idea is to somehow short the nodes V 1 and V G1 when M 2 411 is ON, thereby guaranteeing that M 1 409 is turned OFF; but the circuit also needs to ensure that this new switch should be open when M 1 409 is intended to be ON, thereby preventing loss of charge from C B1 421 during intended operation. There are several embodiments described in the following to do this.
[0022] A first embodiment uses the addition of weak diodes M 7 441 /M 8 443 between V G1 /V G2 and V 1 /V 2 , respectively, as shown in FIG. 5 . Consider when the pump in steady-state and in the Φ 1 phase: When C L 433 is suddenly connected through the switch S 1 431 , V 1 drops suddenly but V G1 does not. When the pump shifts to phase Φ 2 , since the diode M 7 441 is forward-biased, V G1 and V 1 equalizes quickly until V 1 =V G1 −V TH and hence M 1 409 is shut OFF thereby preventing reverse leakage. Since the diode is forward-biased during phase Φ 1 also, it has to be a weak diode. The drop in V G1 due to the forward-biased diode M 7 441 during phase Φ 1 is minute and even this small amount of charge lost by C B1 421 is gained back by C 1 401 and C L 433 . Hence, the drop in power efficiency is minimal. The recovery time now improves as the reverse-leakage path is cut off and there is more charge transferred from C 1 401 to C L 433 in each clock cycle. The power efficiency is also better as the dynamic losses due to the reverse-leakage path are absent.
[0023] A second embodiment adds switches M′ 7 451 /M′ 8 453 between V G1 /V G2 and V 1 /V 2 respectively as shown in FIG. 6 . fhe switches M′ 7 451 /M′ 8 453 are driven by the opposite phase clocks, V G2 /V G1 respectively. Consider the pump of FIG. 6 in steady-state and in the Φ 1 phase: When C L 433 is suddenly connected through the switch S 1 431 , V 1 drops suddenly but V G1 does not. When the pump shifts to phase Φ 2 , the switch M′ 7 451 is turned ON strongly, as its gate-source voltage (V GS ) level is close to 2V DD , thereby shorting V 1 and V G1 . This causes the V GS of M 1 409 to be ZERO and hence, the reverse leakage path is cut off Back in phase Φ 1 , V G2 drops by 2V DD and the switch. M′ 7 451 is turned OFF completely, as long as the drop in voltage V 1 is not very drastic (>V DD +V TH ). Hence, there is no drop in V G1 during phase Φ 1 and the driving capability of switch M 1 401 is unaltered. It is worth noting that there is no possibility for the switches M′ 7 451 /M′ 8 453 to turn ON accidentally as Φ B1 /Φ B2 are non-overlapping clocks by design. For designs working on the limit due to area constraints, a minute loss of driving capability in switches M 1 409 /M 2 411 cannot be tolerated and this new design will help in such cases. A disadvantage of this embodiment relative to that to be discussed next is that it takes some time to cut-off the reverse-leakage path due to the non-overlap time between the boosted clocks Φ B1 /Φ B2 . Hence, some degree of reverse leakage can occur.
[0024] Another embodiment, shown in FIG. 7 , uses depletion-type devices M″ 7 461 /M″ 8 463 instead of enhancement-type devices M′ 7 451 /M′ 8 453 of FIG. 6 for the sorting switches. This causes these switches turn ON immediately after the removal of boosted clocks Φ B1 /Φ B2 , thereby cutting off the reverse-leakage path from the outset. M″ 7 461 is weakly ON when Φ B1 is removed and strongly ON when Φ B2 is applied. However, during phase Φ 1 , the switch M″ 7 461 starts conducting if the voltage drop exceeds a certain level (>V DD −|V TH |). This can be preferable when the drop in voltage is not too much, i.e.; as long as C 1 401 /C 2 403 is comparable to C L 433 .
[0025] A graphical depiction of the operation of the embodiment of FIG. 7 is shown in FIGS. 8A and 8B . FIG. 8A shows the voltage and current profiles for a typical doubler-type charge pump such as in FIG. 3 , whereas FIG. 8B shows the voltage and current profiles for the modified charge pump of FIG. 7 . The charge needed to be transferred to the output in both cases is ∫(I A1 +I A2 )*dt. As shown in FIG. 8B , the negative components (reverse current) of I A1 /I A2 have been reduced greatly, thereby transferring more charge to the output every cycle and reducing the recovery-time.
[0026] The embodiments described above address the reverse leakage issue in doubler-type charge pump architectures. Depending on the charge pump application and design constraints, the preferred embodiment can be chosen for the charge pump. Compared to previous charge pump circuits, the embodiments described here can provide a ramp-up time comparable to the Dickson-type charge pumps, similar I-V performance, and better power efficiency. Charge pump architectures are typically optimized keeping the steady-state performance in mind so as to reduce power consumption, area, or both. Doubler-type charge pump architectures with V TH -cancellation offer distinctly better performance than their Dickson-type architecture equivalents; but the dynamic performance of the pump (ramp-up, recovery-time) is adversely affected and can make it unsuitable for sensitive applications where the Dickson-type architecture may be chosen. The techniques presented here improve the dynamic performance of doubler-type charge pumps along with ensuring better power efficiency, making them comparable to the Dickson-type charge pumps and thereby providing high levels of both steady-state performance and dynamic performance in the same voltage doubler-type charge pump architecture.
[0027] Although the invention has been described with reference to particular embodiments, the description is only an example of the invention's application and should not be taken as a limitation. Consequently, various adaptations and combinations of features of the embodiments disclosed are within the scope of the invention as encompassed by the following claims.
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Techniques are presented to reduce reversion leakage in charge pump circuits. The exemplary circuit is a charge pump of the voltage doubler type, where the output of each leg is supplied through a corresponding output transistor. An auxiliary charge pump is used to supply the gates of the output transistors in order to cancel the threshold voltage of these output transistors. To reduce reverse leakage back through the output transistors, in each leg of the charge pump a switch is connected between the gate of the output transistor and the output level of the leg so the these levels can be shorted when that particular is not supplying the pump's output.
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This application claims priority from U.S. Provisional application Ser. No. 61/340,893 (“the '893 application”) filed Mar. 24, 2010. The '893 application is incorporated herein by reference.
BACKGROUND OF TIE INVENTION
The present invention relates to a method and apparatus for facilitating the connection of tubular used in the oil and gas exploration and extraction industries. More specifically, the invention relates to an apparatus for running or pulling tubular into or out of a well bore.
In the construction of oil or gas wells it is usually necessary to line the well bore with a string of steel pipes commonly known as tubular or tubing or generically as oil country tubular goods (“OCTG”). For purposes of this application, such steel pipes shall hereinafter be referred to as “tubular OCTG”. Because of the length of the tubular OCTG required, individual sections of tubular OCTG are typically progressively added to the string as it is lowered into a well from a drilling rig or platform. The section to be added is restrained from falling into the well by some tubular engagement means, typically a spider or the like, and is lowered into the well to position the threaded pin of the tubular OCTG section adjacent the threaded box of the tubular OCTG in the well bore. The sections are then joined by relative rotation of the sections until such time as the desired total length has been achieved.
It is common practice to use a power tong to torque the connection to a predetermined torque in order to connect the sections of tubular OCTG. This traditional method and equipment types have been used extensively around the world for a period in excess of fifty years. While this method is in daily use it normally requires a large team of specialist personnel along with a plethora of equipment to successfully undertake this task. It is also a very dangerous task with personnel having to be located on a small platform suspended up to 15 feet from the rotary table and the power tong tethered to a steel cable under high loads.
In more recent times, a top drive may be used; this is, a top drive rotational system used for drilling purposes. Where a top drive system is used to make the connection, the use of a surface mounted slip type spider to restrain the section of tubular OCTG to be added may be problematic, due to the configuration of the spider in so much as it sits on or protrudes above the rig floor causing a further obstruction or safety hazard. It is therefore known to make use of an apparatus generically as referred to as an “FMS” or flush mounted spider, which can be inserted into the rotary table so that a section of tabular OCTG may be added or removed, and engaged therewith to hold the section in place. Such apparatus may comprise one or more slips and or toothed grapples, which may be hydraulically or pneumatically operated to engage an outer surface of the tubular. While this is advancement over the traditional approach as it lowers the equipment operational height; it has drawbacks in that because of the design characteristics of the upper section, plates, slips and or grapples may function or operate above the rotary table, thereby becoming a safety or operational problem. This method also places the tubular OCTG to be connected at a height that may still require an additional work table or platform to facilitate the connection thereof.
Secondly as the slips and or grapples tend to be functioned using only two pneumatic or hydraulic cylinders mounted to a horseshoe or split ring whereby side loading of the tools can occur if misalignment is an issue thereby scarring can occur to the outside surface of the tubular OCTG and its integrity thereof.
The intention of the present invention is to offer a much-improved method for an FMS for running tubular OCTG into a borehole without the shortfalls in the tools available today.
SUMMARY OF THE INVENTION
An apparatus has been invented for handling tubular OCTG. The apparatus is mountable inside a rotary table as a true FMS and can be used to grip the tubular OCTG from the outside. The system comprises an outer body, slip backs, slip fronts and gripping pads or die blocks.
The operator can remotely manipulate the FMS to extend or retract the hydraulic or pneumatic cylinders causing a relative movement in the slip bodies and gripper pads or die blocks to grip the outer surface of the tubular OCTG and secure it in the rotary table on the drill floor. Once the operator has activated the hydraulic or pneumatic cylinders thereby causing relative movement in the slip bodies and gripper pads or die blocks to grip the tubular OCTG, then torque may be applied using the rotational capability of the top drive or a traditional style power tong to remotely couple the two joints of tubular OCTG together.
According to a first aspect of the present invention, there is provided an outer body, slip backs, slip fronts and gripping pads or die blocks, wherein the outer body is manufactured utilizing standard machining practices and plate cutting techniques such as torch cutting, plasma cutting, laser cutting, and water-jet cutting thereby eliminating the need for castings.
According to a second aspect of the present invention, the outer body is manufactured and assembled using a bolted and welded construction process.
According to a third aspect of the present invention, each set of slip backs and or slip fronts may each contain a hydraulic or pneumatic cylinder in direct engagement and axial alignment with the slips, thus negating the need for any linking mechanisms there between.
According to a fourth aspect of the present invention, the outer body uses a series of spherical balls or rollers each partially encased by a housing. This allows a portion of each ball or roller to protrude from its respective housing, the protruding portion of the ball or roller to contact the tubular OCTG allowing it to move in a vertical position such is the case running in or out of the hole or in a rotating motion such is the case with drilling, milling, reaming or fishing with casing.
The present invention may further comprise a control system that is able to manipulate the hydraulic or pneumatic cylinders and other elements of all aspects of the present invention. The control system of the present invention is able to manipulate the hydraulic or pneumatic cylinders utilizing either a wireless communication system or a system of hydraulic or pneumatic control line umbilical. The system may also be coupled conventionally using a series of cables should the use of wireless communication be restricted.
The control system is also able to set and unset the hydraulic or pneumatic cylinders used to manipulate the slip backs, slip fronts and gripping pads or die blocks to contact the tubular OCTG thereby to secure the tubular OCTG in the rotary table. The control system is also able to monitor feedback loops that include sensors or monitors on the elements of the present invention. For example, sensors of the control system of the present invention may monitor the open and close status of transfer elevators, the status of a hydraulic actuator and the set or unset position of the slipper gripper pads or die blocks. The control system is designed or rated for use in a hazardous working environment. Communication with the processor of the control system is accomplished through a wireless communications link. The control system is also able to monitor feedback loops that include sensors or monitors on the elements of the present invention. For example, sensors of the control system of the present invention monitor the open and close status of the FMS and or other elements. The control system is designed or rated for use in a hazardous working environment. Communication with the processor of the control system can be accomplished through a wireless communications link, these may include Zone 1 or Zone II certified components. The hydraulic circuit shall contain a metering device such that all hydraulic or pneumatic cylinders stroke at a uniform rate upon activation.
By reversing the process the tubular OCTG members can be removed from a well bore if desired.
it is an object of this invention to provide a tubular gripping apparatus for supporting or handling a tubular, with a) two or more main upper plates and two or more lower plates forming an opening there through to accept a tubular (a “tubular guiding system”), b) a plurality of slip assemblies evenly distributed about a central axis, c) each slip assembly comprising a slip back, a slip, one or more die inserts, and a hydraulic or pneumatic cylinder, and d) each of said slip backs are affixed to a main upper plate and a lower plate, and the entire assembly is hinged in at least one place thereby allowing the gripping apparatus to open, allowing a tubular to be inserted or removed in a radial direction in relation to the central axis, and a hinge pin is substantially retained to the gripping apparatus by some means such as threads, retainer rings, snap rings, set screws, cotter pins, R clips, etc. with at least one pin being removable to allow the gripping apparatus to open. It is further intended that the slips be in sliding engagement with the slip backs and the slips move in both a vertical and radial direction simultaneously as they travel up or down the inclined surface of the slip backs, the slips are in sliding abutment with the slip backs, and the slips move in both a vertical and radial direction simultaneously as they travel up or down the inclined surface of the slip backs, which inclined surfaces may be between 6 degrees and 20 degrees in relation to a vertical axis or between 9 degrees and 14 degrees in relation to a vertical axis
It is a further object of this invention that the hydraulic or pneumatic cylinders are mounted in a cavity formed between the slips and slip backs, thus are in axial alignment with the inclined surfaces of the slips and slip backs, and the hydraulic cylinders are configured such that hydraulic pressure is applied to the largest area of the hydraulic piston for exerting a force to urge the slips down the inclined surface toward a gripping or latched position, thus providing for maximum gripping force for a given applied hydraulic pressure, and further that the hydraulic or pneumatic cylinders are in direct engagement and axial alignment with the slips, thus negating the need for any linking mechanisms there between, and hydraulic or pneumatic fittings connected to the retract or extend port of the hydraulic cylinders are housed in a cavity in the slip backs.
It is further intended that a slip back and slip may be manufactured from a single piece of steel utilizing wire EDM (electrical discharge machining) to cut the inclined profile, thus providing a matched sliding fit there between and the inclined surfaces of the slips and slip backs are coated with a friction reduction material, plating or process such as Teflon, Xylan, chrome plating, hard dense chrome plating, diamond chrome plating, electroless nickel, etc., or plain bearing or self lubricating material such as an acetal filled bronze, etc. Likewise, all components can be manufactured utilizing standard machining, EDM (electrical discharge machining), and or forging practices as well as plate cutting techniques such as plasma cutting, laser cutting, torch cutting, and water-jet cutting, thus eliminating the need for castings and the means of attaching individual components to form a complete unit includes both bolting and welding.
It is also intended that the tubular guiding system is affixed to the upper plate (s), wherein the tubular guiding system is hinged to open in two different directions, 90 degrees to each other, and the tubular guiding system utilizes a high density urethane, polymer coated, plastic, composite or alloy member affixed or bonded to a steel member of the guiding system.
It is an object of this invention to provide a tubular gripping apparatus to be used as a flush mounted spider wherein the upper plates are configured to fit standard rotary tables, the main upper and lower plates contain one or more notches or recesses to allow the running of umbilical or control lines while running tubulars and the tubular guiding system includes a roller for assisting in running umbilical or control lines.
It is an object of this invention to provide a tubular gripping apparatus to be used as an elevator or a top drive mounted tubular running tool.
It is an object of this invention to provide a tubular gripping apparatus controlled remotely from a manual hydraulic control console, or an electro-hydraulic control console, or wirelessly controlled remotely from a touch screen or any combination thereof.
It is an object of this invention to provide a tubular gripping apparatus wherein all slip movement takes place below the rig floor and/or rotary table.
It is an object of this invention to provide a tubular gripping apparatus for supporting a tubular, with; a) a body forming an opening there through to accept a tubular, b) a plurality of slip backs evenly distributed about a central axis, c) said slip backs are constituents of said body, d) said body containing one or more torque transfer members for engagement with the rotary table, whereby torque and or reactive torque is transferred from the body to the rotary table, and where all slip movement takes place below the upper plates and/or below the rig floor and/or rotary table.
It is an object of this invention to provide a tubular gripping apparatus for handling a tubular, with a) a body forming an opening there through to accept a tubular, b) a plurality of slip backs evenly distributed about a central axis, c) said slip backs are constituents of said body d) said body containing lifting ears to provide a means of attachment to the bail arms.
It is an object of this invention to provide a tubular gripping apparatus for supporting a tubular, with; a) a body forming an opening there through to accept a tubular, b) two or more slip backs evenly distributed about a central axis, e) said slip backs are constituents of said body, d) a cavity is formed between each slip and slip back, e) a hydraulic cylinder is mounted in said cavity, and where all slip movement takes place below the upper plates and/or below the rig floor and/or rotary table.
It is an object of this invention to provide a tubular gripping apparatus for handling a tubular, with a) a body forming an opening there through to accept a tubular, b) two or more slip backs evenly distributed about a central axis, c) said slip backs are constituents of said body, d) a cavity is formed between each slip and slip back, e) a hydraulic cylinder is mounted in said cavity.
It is an object of this invention to provide a tubular OCTG supporting spider for use on a drilling rig, work-over platform, hydraulic work-over or snubbing unit with; a) a body which includes one or more upper plate (s) to be securely located in a rotary table, b) said body containing an opening there through to accommodate a tubular, c) two or more slip assemblies are evenly distributed about a central axis, d) each said slip assembly comprising a slip back, a slip, one or more die inserts, and a hydraulic cylinder, and where all slip movement takes place below the upper plates and/or below the rig floor and/or rotary table.
It is an object of this invention to provide a tubular OCTG handling elevator for use on a drilling rig, work-over platform, hydraulic work-over or snubbing unit, with; a) a body which includes lifting ears to provide a means for attachment to the bail arms, b) said body containing an opening there through to accommodate a tubular, c) two or more slip assemblies are evenly distributed about a central axis, d) each said slip assembly comprising a slip back, a slip, one or more die inserts, and a hydraulic or pneumatic cylinder.
It is an object of this invention to provide a tubular gripping apparatus for supporting or handling a tubular, with a) two or more main upper plates and two or more lower plates forming an opening there through to accept a tubular; b) a plurality of slip assemblies evenly distributed about a central axis; c) each slip assembly comprising a slip back, a slip, one or more die inserts, guide plates, and a hydraulic or pneumatic cylinder; d) each of said slip backs are affixed to a main upper plate and a lower plate, and where all slip movement takes place below the upper plates and/or below the rig floor and/or rotary table.
It is an object of this invention to provide a tubular OCTG supporting spider for use on a drilling rig, work-over platform, hydraulic work-over or snubbing unit with: a) a body which includes one or more upper plate (s) to be securely located in a rotary table, b) said body containing an opening there through to accommodate a tubular, c) two or more slip assemblies are evenly distributed about a central axis, d) each said slip assembly comprising a slip back, a slip, one or more die inserts, guide plates, and a hydraulic cylinder, and where all slip movement takes place below the upper plates and/or below the rig floor and/or rotary table.
It is an object of this invention to provide a tubular OCTG handling elevator for use on a drilling rig, work-over platform, hydraulic work-over or snubbing unit, comprising: a) a body which includes lifting ears to provide a means for attachment to the bail arms b) said body containing an opening there through to accommodate a tubular, c) two or more slip assemblies are evenly distributed about a central axis, d) each said slip assembly comprising a slip back, a slip, one or more die inserts, guide plates, and a hydraulic or pneumatic cylinder, and where all slip movement takes place below the upper plates and/or below the rig floor and/or rotary table.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other aspects of the present invention will now be described by way of example only and with reference to the accompanying drawings, in which:
FIG. 1 is sectioned elevation view of the gripping apparatus with a tubular situated along the central axis, sectioned along line A-A of FIG. 5 .
FIG. 2 is a top view of the slip back.
FIG. 3 is a top view of the slip.
FIG. 4 is a top view of the slip assembly.
FIG. 5 is a top view of the gripping apparatus assembly.
FIG. 6 is a top view of the tubular guiding system.
FIG. 7 is a top view of a series of rollers as a second embodiment of the tubular guiding system.
FIG. 8 is a top view of a multi faced die insert.
FIG. 9 is a top view of a curved die insert.
FIG. 10 is a top view of a V shaped die insert.
FIG. 11 is a top view of a multi faced die insert with nodules.
FIG. 12 is a top view of a curved die insert with nodules.
FIG. 13 is a top view of a V shaped die insert with nodules.
FIG. 14 is an elevation view of a die insert with a symmetric dovetail.
FIG, 15 is an elevation view of a die insert with a non-symmetric dovetail.
FIG. 16 is a top view of a slip assembly with guide plates.
FIG. 17 is an elevation view of a slip assembly with guide plates.
DETAILED DESCRIPTION OF THE INVENTION
It will be apparent that many other changes may be made to the illustrative embodiments, while falling within the scope of the invention and it is intended that all such changes can be covered by the claims appended hereto.
Although the disclosed embodiments have been described in detail, it should be understood that various changes, substitutions and alterations can be made to the embodiments without departing from their spirit and scope. Other technical advantages of the present invention will be readily apparent to one skilled in the art from the following figures, drawings, descriptions and claims.
Referring to the drawings, shown is a gripping apparatus for supporting or handling a tubular member. The apparatus in its entirety is identified by the reference numeral 100 .
FIG. 1 shows a sectioned elevation view of the gripping apparatus 100 , sectioned about line A-A of FIG. 5 . This gripping apparatus can be used as a flush mounted spider to operate in a rotary table or an elevator suspended by bail arms. Illustrated in this view are the top plates 1 which are affixed to the upper surface of the slip backs 3 . The lower surface of the slip backs 3 are affixed to the lower plates 2 . Slips 4 are in sliding engagement with the slip backs 3 . Die inserts 5 are attached to slips 4 via a symmetric dovetail profile 24 or a non symmetric dovetail profile 25 or the like, both as shown in FIGS. 14-15 . These profiles may be vertical or horizontal. Double acting hydraulic cylinders 6 are disposed in a cavity formed between slip backs 3 and slips 4 . The hydraulic cylinders 6 are threadedly connected to a lower surface of slips 4 at surface 31 . The upper portion of the hydraulic piston 8 is the largest area of the piston, thus providing a maximum force in a downward direction for a given applied pressure. This provides a greater force to stroke the hydraulic cylinder to latch and grip a tubular than the force to release the grip on a tabular and retract the cylinder. The hydraulic cylinder rod 7 protrudes through a bore in the lower portion of the cylinder. The slip backs 3 contain a cavity 30 to allow pressure conduits access to the retract port of the hydraulic cylinders. A tubular T is disposed in the opening of the gripping apparatus along the central axis.
FIG. 2 illustrates the low bearing profile 36 and cavity profile 9 of the slip backs 3 . These profiles also provide a means for the sliding engagement between the slip backs 3 and the slips 4 . The load bearing surface 36 of the slip backs 3 is in sliding abutment with the load bearing surface 37 of the slips 4 . These surfaces are coated with a friction reduction material or process. These friction reduction techniques aid in the efficiency of the gripping apparatus and also prevent or reduce the possibility of the abutting surfaces from friction welding to one another under heavy loads.
FIG. 3 illustrates the load bearing profile 37 and cavity profile 9 a of the slips 4 . The cavities 9 and 9 a of the slip backs and slips respectively form a cylindrical cavity wherein the hydraulic cylinders are disposed. This cylindrical cavity is in axial alignment with the inclined surfaces of the slip backs 3 and slips 4 . This allows the hydraulic cylinders to also be in axial alignment with the slips 4 , thus forcing the slips 4 directly up or down the inclined surface to release or grip the tubular. This removes the necessity of having linkages between the hydraulic cylinders and the slip mechanisms. For this reason, all potential forces of the hydraulic cylinders are realized. Linkages are necessary when the hydraulic , cylinders are positioned at any angle other than that of the inclined surfaces. This causes losses of the hydraulic forces as well as additional linkage parts and associated connecting pins which can be potential weak points.
FIG. 4 illustrates a slip assembly 10 constituted by the slip backs 3 and slips 4 in sliding engagement with one another. Also shown is the cylindrical cavity formed between the slip backs 3 and slips 4 . The inclined surface where load bearing surfaces 36 and 37 abut is designated as inclined surface 11 . Not shown in this view are the die inserts due to the many variations possible. See FIG. 8 through FIG. 15 for possible variations.
FIG. 5 shows a top view of the gripping apparatus 100 utilizing two (2) top plates 1 and four (4) slip assemblies 10 disposed equally about the central axis. One or more notches 27 are placed into the top plates for accommodating the running of umbilical's, control lines, or the like when the gripping apparatus 100 is being utilized as a flush mounted spider. At least one of these notches 27 will be aligned with roller 16 such that umbilical's can be guided through the gripping apparatus 100 without damage. Also shown in the top plates 1 are holes 28 and 29 to accommodate the hinge pin (not shown) and removable connecting pin (not shown). These pins are to facilitate the opening of the gripping apparatus in the event a tubular must be removed in a radial direction with relation to the central axis.
FIG. 6 is a top view of the tubular guiding system 50 which includes two (2) upper doors 13 and one (1) lower door 14 . The upper doors 13 are hinged to open about axes 18 via hinges 11 . The hinges 11 are affixed to both the upper doors 13 and lower door 14 . Lower door 14 is hinged about axis 17 via hinge 12 . Hinge 12 is affixed to both the lower door 14 and one of the top plates 1 or an additional plate (not shown) which would be affixed via bolts to a top plate 1 . Thus, the two upper doors 13 are able to open independently of one another. Also, the lower plate 14 is able to open which in turn causes the attached upper doors 13 to follow suit. Attached to the upper plates 13 are guides 15 . These guides 15 may be fabricated from materials such as steel, aluminum, bronze, brass, aluminum bronze, polyurethane, composites, plastics, etc. or a combination thereof. In lieu of the guide 15 , a roller type guide assembly 34 may be utilized as is shown in FIG. 7 . This system uses a series ball rollers 19 each partially encased by a housing. This allows a portion of each ball bearing to protrude from its respective housing. This protruding portion of the ball contacts the tubular allowing it to move in a vertical position such is the case running in or out of the hole or in a rotating Motion such is the case with drilling, milling, reaming or fishing with casing.
FIG.'s 8 through 15 illustrate various geometries, features, and profiles of the die inserts 5 . FIG. 8 shows one embodiment of a die insert having a multi-faced gripping profile. FIG. 9 shows a curved gripping profile. FIG. 10 shows a V shaped gripping profile. FIGS. 11 through 13 show the same gripping profiles mentioned above with the addition of nodules on the gripping faces. These nodules may be of various shapes such as hemispherical, nodular, lumpy, sinusoidal, waveform, etc. or any combination or multitude thereof. In addition, any of the above mentioned surface profiles may be smooth, smooth and hardened, toothed, grit coated, toothed and grit coated, etc. or a combination or multitude thereof.
FIG. 14 shows a die insert 5 with a symmetrical dovetail profile 24 on its side opposite the gripping surface. This dovetail profile 24 is used as a means of attaching the die insert 5 to the slip 4 in a manner whereby the die insert can be readily changed. The need arises to change out these die inserts for several reasons such as: the outside diameter of the tubular to be gripped has changed, a different profile is needed for a specific tubular material or weight, or the die insert wears out and is no longer functional, etc. FIG. 15 is the same as FIG. 14 with the exception that the dovetail profile 25 is non symmetric.
FIG. 16 is a top view of a slip assembly illustrating the use of guide plates 32 bolted to the sides of the slip 4 and engaged with guide ways 34 . The plates feature an interlocking profile 35 which is in sliding engagement with guide way 34 of the slip back 3 . These plates are attached via bolts 33 . The plates could alternatively be bolted to the slip back 3 with the guide way 34 on the slip 4 . Also, the guide ways 34 are shown as machined slots (female profile), but could alternatively be male profiles. These guide plates 32 allow the slips 4 to be easily removed from the slip backs 3 for servicing.
FIG. 17 is an elevation view of the slip assembly utilizing the guide plates 32 and guide ways 34 .
It will be apparent to those skilled in the art that many other changes can be made to the illustrative embodiments, while falling within the scope of the invention and it is intended that all such changes be covered by the claims appended hereto.
Although the disclosed embodiments have been described in detail, it should be understood that various changes, substitutions, or alterations can be made to the embodiments without departing from their spirit and scope. Other technical advantages of the present invention will be readily apparent to one skilled in the art from the following figures, drawings, descriptions and claims.
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A method and apparatus for facilitating running or pulling tubulars from a well bore whereby the functions of a surface mounted traditional spider/elevator are replaced by an FMS which may also be remotely controlled. The FMS comprises a main body consisting of upper and lower plates assembled in a bolted and welded configuration, a slip assembly each said slip assembly comprising a slip back, a slip, one or more die inserts, a hydraulic or pneumatic cylinder and multiple sized die blocks to conform to the tubular OCTG diameter.
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This application claims benefit to U.S. provisional application No. 60/164,479 filed Nov. 10, 1999.
BACKGROUND OF THE INVENTION
This invention relates to tufting machines for producing tufted textile goods such as carpet, upholstery and the like and more particularly to a hollow needle tufting machine of the type disclosed in U.S. Pat. Nos. 4,549,946; 4,991,523; 5,080,028; 5,158,027; 5,165,352; 5,205,233 and 5,267,520 and is an improvement over the apparatus and methods disclosed therein.
U.S. Pat. No. 4,549,946 discloses a tufting apparatus of this type for producing patterned tufted goods using yarns of different colors or different textures. This apparatus is capable of placing yarn into a backing to create patterns and designs which were then previously generally available only from a weaving loom or by using printing techniques. The apparatus employed multiple heads spaced across the width of a backing material. Each head included a reciprocating hollow needle for penetrating the backing and for implanting yarn tufts into the backing by feeding yarn through the needle pneumatically. The needle is connected to a yarn exchanger into which a plurality of yarns of different colors, for example, are supplied and a mechanism is included which enables a selection of a yarn for implantation into the backing for each penetration by the needle. The multiple heads were stepped in synchronism across the backing for a distance corresponding to the spacing between the heads in order to implant a transverse row of yarn tufts. The backing was then advanced to the position of the next row and the process repeated to implant the next row. A computer controlled the selection of the yarn implanted by each needle for each penetration of the backing in order to produce a desired pattern in the finished goods.
A significant factor influencing the production speed of practical apparatus employing the aforesaid patented disclosure is the number of tufting heads embodied in the apparatus. The greater the number of heads, the less distance each head had to traverse and, accordingly, the faster a row of tufts could be implanted into the backing. As the number of heads increased, however, other problems arose. The increased weight made it more difficult to move the heads accurately and to maintain their alignment and positions relative to one another. Thus, rather than the multiple heads which carry the hollow needles being moved across the backing, U.S. Pat. No. 4,991,523 proposed that the backing rather than the heads be shifted transversely to move substantially less weight. Not only did this simplify the transverse shifting apparatus but also provided greater speed and accuracy to the yarn placement.
The shifting of the backing material results in a number of transversely spaced stitches produced by each needle, the spacing between adjacent stitches or tufts being equal to the stitch gauge of the product produced. For example, if the needles are spaced apart by two inches, as has been and remains the case in the machines produced using the disclosures of the aforesaid patents, and the gauge or space between adjacent stitches is {fraction (1/10)} inch, the backing is shifted a total of 20 steps from the first penetration of the backing by a particular needle to the last penetration of the backing by that needle before the fabric is shifted in the opposite direction. Accordingly, if the needles could be spaced apart by less than the two inches mandated in the prior art in view of the number of feed mechanisms involved, i.e., a separate feed mechanism for each yarn for each needle, then the number of shifts required to be made by the fabric would be less and therefore the time required to produce a fabric of a given length would be reduced. This, of course, translates into an increased speed of operation, speed being a major drawback of machines in the prior art.
Another significant factor influencing the cost and accuracy of this type of tufting apparatus is the control over the feeding of the yarn to the hollow needles. The feeding of the yarn must be positive, and when a yarn change is to be made for a particular needle, the yarn previously stitched by the needle has to be positively withdrawn from the needle so that the subsequent yarn will not be blocked by the previously sewn yarn. Unless this withdrawal of the previously sewn yarn in the prior art apparatus and method is assured, a substantially greater air pressure is required to supply the subsequent yarn through the needle. Furthermore, when the yarn is withdrawn from the needle, unless the yarn withdrawal is controlled, the next time that yarn is required to be fed to the needle an accurate and consistent length of yarn can not be assured. This would also result in requiring additional air pressure to assure that a sufficient length of yarn is supplied. The effect is that a greater than required amount of pressure must be utilized, and if too much yarn is supplied to the needle additional yarn shearing operations are required for producing a satisfactory product. Accordingly, in U.S. Pat. No. 5,080,028 a pullback mechanism is disclosed which is disposed between the yarn feeder and the hollow needle, the pullback mechanism acting to pull the yarn a preselected amount from the needle so that the yarn passageway in the needle is not restricted by the previous yarn when a subsequent yarn is to be sewn. Additionally, to assure that the pullback mechanism draws the yarn from the needle and not from the yarn supply or the feed roller, clamping apparatus had to be disposed between the yarn feed roller and the pullback mechanism to positively clamp the yarn when the yarn change is to be made. The pullback mechanism is thereafter activated and the yarn feed roller ceases positive feeding of the yarn. Thus, the yarn pullback mechanism draws a predetermined amount of yarn from the needle maintaining it in reserve until again required. Additionally, the yarn feed roller as it ceases positive feeding draws a preselected amount of yarn from the yarn supply for subsequent use when needed. When the needle is to commence stitching with a particular yarn, the yarn feed roller is activated and the yarn clamping apparatus and yarn pullback mechanism are deactivated.
A further significant factor affecting the efficiency and cost of the aforesaid apparatus and its operation is the amount of pressurized air that must be supplied to feed a selected yarn through the system from the yarn injectors which receive the yarn associated with a respective needle and directly on through separate passageways to the yarn exchanger in which yarn exchange occurs. In the early machines, air was supplied to a plenum from which air was directed to a tapered space leading into each yarn carrying conduit extending to the yarn exchanger. Air was thus constantly supplied to the plenum under high pressure to drive the yarn fed by the yarn feed rollers. This resulted in a substantial amount of wasted air and the system was thereafter modified. Air flow was then regulated and controlled so that air under a high pressure was only supplied to a passageway having the selected yarn for injection into and through the needle, while air under a low pressure is supplied to the other passageways. Thus, both low and high pressure air flows into the funnel of the yarn exchanger. This, however, resulted in a turbulence so that the various yarns became entangled, and this problem was in turn solved by disposing an air jet in the yarn exchanger adjacent to the entry to the needle for blowing air into the needle inlet to prevent the selected yarn from being diverted and tangled with one or more of the other yarns.
The yarn exchanger in these machines has the form of a funnel with each yarn adapted to enter the enlarged end through a separate passageway and the air jet is in the form of a nozzle disposed for blowing the selected yarn into the needle. The selected yarn is fed to the needle by high pressure air within its passageway while low pressure air flows through the other passageways. Accordingly, a substantial amount of air under pressure to must be directed into the yarn exchanger funnel.
With all these changes the method and apparatus heretofore discussed still retains major drawbacks that substantially and significantly limit its acceptance. First and foremost is the slow production rates because of the spacing between adjacent needles, and the other major drawback is the high energy consumption and noise levels due to the large amount of compressed air that must be utilized for the aforesaid reasons. The high air consumption has also been a limiting factor toward increasing production rates by precluding an increased number of hollow needles per machine.
Thus, it may be seen that there has always been a need for greater speed and thus production efficiency for these hollow needle tufting machines and that there is a need to reduce the amount of air required by the machines to reduce production cost. Additionally, not only does the large air flows require large compressors, but the noise levels associated with these air flows is great.
SUMMARY OF THE INVENTION
Consequently, it is a primary object of the present invention to provide a hollow needle tufting machine and a method for operating the same with increased production rates and lower air flow requirements than machines of the prior art.
It is another object of the present invention to provide apparatus permitting a greater number of needles in a hollow needle tufting machine than permitted by the prior art.
It is a further object of the present invention to provide a method and apparatus permitting a plurality of yarns to be disposed within a hollow needle of a hollow needle tufting machine and not pulling any of the yarns which are not being sewn back out of the needle.
In accordance with the present invention the requirement for a yarn exchanger has been eliminated and all of the yarns to be sewn by a given needle are maintained within the needle below the entry thereto and just above the exit opening. The plurality of yarns that are not being sewn are not retracted from the needle thereby removing the necessity of having a yarn exchanger as in the prior art, and the plurality of yarns are held within the needle during the machine cycle by a single air injector, preferably with multiple jets or openings, disposed at the entry to the needle.
Furthermore, it may be possible to remove the high and low air solenoids, air solenoids formerly required for retracting arms, air cylinders for retracting arms, some air manifold assemblies, individual yarn injectors, individual tubes or conduits for each yarn, some assemblies formerly required of a needle bar, an individual supply of air for each yarn at any given time, flexible ribbon hoses provided from air manifold assemblies to each individual yarn, and/or final entries over a needle inlet at the needle bar. Of course, in some embodiments many of these elements may be retained, as so desired.
Additionally, an improved needle includes a plurality of openings located along its length. Preferably these openings are drilled at angles relative to the length of the needle to unsubstantially affect the airflow in the downward direction. However the holes may act as relief vents when air moves in the upward direction, such as may result from back pressure generated when the bottom of the needle (typically the pointed end with the yarn opening) is obstructed during the tufting and/or cutting process.
The angled holes along the length of the needle have been found to reduce the tendency of back pressure generated during the tufting process to force yarns out of the top of the needle, thereby “unthreading” the needle and inhibiting the sewing process.
These changes reduce the amount of air required during operation and not only reduce the size and cost of the required compressor, but also the noise levels associated therewith to acceptable levels. By eliminating the multiplicity of yarn exchangers, which in the prior art comprises one yarn exchanger per needle, a substantially greater amount of space is made available for mounting additional yarn feed mechanisms. Thus, the number of needles may be increased accordingly so as to increase the production speed of the machine.
Consequently, the present invention eliminates the yarn exchangers of the prior art and disposes all of the yarns within each needle. Eliminating the yarn exchangers provides space for additional yarn feed mechanisms. Since there is one yarn feed mechanism for each yarn per needle, additional needles may be carried by the needle bar. Increasing the number of needles, increases the productivity and effectively the speed of the machine. Furthermore, a significant decrease in the number of rotating parts, i.e., mass, allows for higher needle bar reciprocating speeds due to reduced forces and vibration levels. Higher reciprocation speeds may result in higher production levels due to higher obtainable machine speeds. Thus, not only does the present invention provide lower production costs and machine costs by reducing the amount of air flow required, but productivity may be increased substantially.
It is anticipated that at least twice as many needles may be utilized in a hollow needle tufting machine of this type so that the space between adjacent needles rather than being two inches as required in the prior art may be no more than, and possibly less than, one inch between needles. With a gauge of {fraction (1/10)} inch, as opposed to the 20 steps required in the prior art, only 10 steps are required by a machine having twice the needle constructed in accordance with the present invention. Accordingly, the effective speed of the machine is at least double that of the prior art. It may also be that the space made available for feed mechanisms by means of the present invention will prove to be such that more than twice the number of feed mechanisms may be used. In that case the expected speed of the machine would be increased accordingly.
BRIEF DESCRIPTION OF THE DRAWINGS
The particular features and advantages of the invention as well as other objects will become apparent from the following description taken in connection with the accompanying drawings, in which:
FIG. 1 is a side elevational view, in cross section and diagrammatic, of tufting apparatus embodying the present invention;
FIG. 2 . is a fragmentary front elevational view of the yarn feed apparatus associated with two needles of the present invention; and
FIG. 3 is a fragmentary rear elevational view greatly enlarged illustrating a pair of needles and the needle bar and injector portion of the apparatus illustrated in FIG. 1 .
FIG. 4 is a fragmentary elevational view of a single needle illustrated in FIG. 3 .
DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 illustrates a tufting machine 10 constructed in accordance with the principles of the present invention, the machine having a plurality of hollow and perforated needles 12 (illustrated in greater detail in FIGS. 3 and 4) for penetrating a backing material 14 to implant yarn tufts 16 therein. The backing material 14 may be advanced longitudinally past the reciprocating needles by a backing advance or feeding system which may comprise a pair of pin rollers 18 and 20 which are driven my motors (not illustrated) at slightly different rotational speeds so as to maintain the backing under tension as it passes beneath the reciprocating needles. The backing advance system may include guide rollers (not illustrated) which cooperate with the pin rollers to guide the backing. A second pair of pin rollers 22 , 23 carried by a frame 24 may be mounted above and below the backing material so as to aid in shifting the backing material laterally or transversely. The backing movement through the machine is not continuous, but is moved in steps at a rate substantially equal to half of the stitch rate per step. During each step the backing is also shifted one lateral or transverse step.
Thus, each needle may insert yarn into the backing at a number of transverse locations. The transverse positioning mechanism (not illustrated) may be any of a number of commercially available devices and, in accordance with advantages provided by the present invention may be a servo motor, gear motor or a linear actuator which may drive the needle plate 26 over which the backing is fed and which acts with the rollers 22 , 23 and frame 24 to shift the backing in accordance with a pattern.
The needles 12 may be reciprocated by an adjustable cam assembly 28 which is coupled to the needles by a link assembly 30 , the adjustable cam assembly comprising a cam 32 essentrically mounted on a main shaft 34 and connected by a yoke member or connecting strap 36 to the link assembly. The link assembly 30 may comprise a connecting link 38 which is pivotally connected to the push rods 40 at the lower ends thereof so as to reciprocate the push rods. The needle bar 42 is connected at the lower ends of the push rods and carries the needles 12 . The yarn exchanger as used in the prior art may be eliminated and the needle bar 42 need not have a funnel entry or individual conduits for yarns in order to eliminate mass. However, some or all of these elements may be useful in some embodiments.
Disposed within the needle bar is a tube 48 which comprises an air injector for blowing air to maintain the positions of the plurality of yarns within the needle bar 42 for reasons hereinafter described. Preferably, as illustrated, the lower ends of the injector is at the exit of the needle bar 42 and in the inlet of the needles 12 . The injector preferably includes a plurality of jets or openings 49 . The injector may have a larger diameter than the interior passageway of the needle 12 in order to ensure adequate airflow into the needle 12 . As hereinafter described, each injector is fed with air from an air supply line 50 fed with air from an air manifold 52 . Locating the air injector 48 in the position illustrated at the inlet of the needle rather than in a funnel in a raised position above the needle as in the prior art, air within the funnel may be “eliminated” so as to eliminate the turbulent flow characteristics in the finnel of the prior art apparatus. It also ensures that the yarn strands are maintained within the needle.
A plurality of yarn strands 54 a, 54 b, 54 c, 54 d, 54 e, 54 f fed by means hereinafter described are disposed within the body of the needle at all times. Because of this, the yarn exchangers required in the prior art apparatus are no longer required. Thus, space is made available for mounting a substantially greater number of yarn feed devices 56 than has been available in the prior art. A yarn strand e.g. 54 a from a source, such as a creel (not illustrated) is fed to the machine and enters through a top yarn guide 58 , is fed through other yarn guides 60 , 61 and through a tension device 62 comprising a pair of rolls 64 , 65 to another yarn guide 66 . From this yarn guide the yarn strand is threaded through the yarn feed mechanism 56 between a pair of gears 68 , 70 to a lower yarn guide 75 . Another yarn guide 72 may be included for feed mechanisms disposed at upper portions of the machine. The lower yarn guide 75 receives a plurality of different yarns e.g. 54 a, 54 b, 54 c, 54 d, 54 e, 54 f.
In the prior art, air was continuously supplied to the passageways, low pressure being supplied to those yarns which were not selected to be sewn into the backing while high pressure air was supplied to the yarn passageway selected to be sewn into the backing on a particular stitch. Thus, air was always applied to the tubes. In accordance with the present invention this is not necessary, nor are the parts necessary. However, in some embodiments, some or all of these elements may be used with the structure and methodology taught herein. During the needle thread-up process, the yarn is forced by the air injector into the needle 12 . During the tufting process the yarn being sewn and the other yarns within the needle are held in the needle by air pressure acting on the yarns from the injector 48 .
Each yarn for each needle has a separate yarn feed apparatus 56 , a computer or the like (not illustrated) programmed with a pattern conventionally selects the particular yarn which is to be tufted into the backing material. The yarn is selected by activating the yarn feed mechanism 56 for that particular yarn. As aforesaid, this mechanism comprises a pair of gears 68 , 70 that are spring loaded so as to be forced together by means of a leaf spring 80 . The gear 70 has a fixed shaft, while the other gear 68 has a floating shaft. Because yarn is threaded between the gears, the gears hold the yarn and prevent the yarn from feeding to the needle unless a particular yarn is selected. An air actuator 82 extends to a pivotally mounted arm 84 on which the gear 68 is mounted, the other end of the air actuator being connected to a solenoid valve 86 which when opened permits air to flow to the actuator. Moreover, the gear 70 meshes with a feed gear 88 that is rotated by a servo motor, or gear motor, actuated when the solenoid 86 is actuated thereby to rotate the gears to feed the selected yarn strand e.g. 54 a. The air from the injector 48 within the needle bar thereafter blows or drives the yarn through the needle. By timing the reciprocation of the needle bar with the feeding of the yarn, a stitch is sewn into the backing material after the needle penetrates the backing. As the needle exits the backing, the yarn remains therein in view of the flow of the air through the needle and the backing closes around the yarn. As the needle reciprocates above the backing material, the backing feeds longitudinally and traverses laterally by means of the lateral shifting apparatus and the needle is thereafter again reciprocated in a downward path, the same or another yarn being selected to be fed through the needle into the backing. The apparatus may include a cutting mechanism including a blade 90 for cutting the yarn which has been tufted into the backing. After a tuft has been formed, the gear mechanism of the feed mechanism for that particular yarn may be deactivated so that although that yarn will remain within the needle, it will not again sew or tuft until it is again selected by the computer. Another yarn residing within the needle may be selected to thereafter be fed and sewn as described.
The needles 12 of the preferred embodiment are illustrated in greater detail in FIGS. 3 and 4. The needles 12 may include a plurality of vents or holes 15 . The holes communicate an exterior surface 17 with an interior surface 19 of the needle 12 . Furthermore the holes 12 may be drilled, or otherwise formed, in the needle 12 during the process of making the needles 12 at at least one angle α relative to an axis 21 located along the length of the needle 12 and directed in the upward direction toward the needle bar 42 . It is preferred that a single angle α be between about 5 and about 80 degrees, between about 10 and about 70 degrees, between about 15 and about 60 degrees, and between about 20 and about 45 degrees. Multiple angles α could also be utilized.
As illustrated in FIG. 3, yarns 54 a-f enter the needle 12 at inlet 23 and proceed into the needle cavity 25 where they remain until one of the yarns is selected for use as described above. Once selected for use, the yarn exits the cavity 25 at yarn exit 13 and may be sewn, or tufted, into a backing material when the point 27 penetrates the body material.
Since all the yarns that are to be selected to be sewn by a needle remain within the needle, the yarn exchangers are not required. This provides space for additional yarn feed mechanisms so that banks of such mechanisms may be aligned transversely at both upper and lower locations as illustrated in FIG. 2 . Thus, at least twice the number of feed mechanisms may be used. This thereby allows at least twice the number of needles and hence at least twice the effective speed of the machine relative to the prior art. A reduction in mass of reciprocating parts also affords higher speeds and additional production.
Another advantage of the construction includes the ability to reduce the amount of compressed air supplied for any given needle. Instead of having an injector for each yarn supplied to a needle, the preferred embodiment utilizes a single injector 48 for all the yarns supplied to a given needle. Therefore, the quantity of compressed air supplied to a particular tufting machine is drastically reduced making closer needles more practical, if so desired.
Numerous alterations of the structure herein disclosed will suggest themselves to those skilled in the art. However, it is to be understood that the present disclosure relates to the preferred embodiment of the invention which is for purposes of illustration only and not to be construed as a limitation of the invention. All such modifications which do not depart from the spirit of the invention are intended to be included within the scope of the appended claims.
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A method and apparatus for tufting comprises a hollow tufting needle supplied with a plurality of yarns. The plurality of yarns are maintained within the cavity of the needle. One of the yarns is selectively fed out of a yarn opening by releasing the yarn from a yarn feed device and utilizing an air injector proximate to the yarn entrance of the needle to assist in expelling the selected yarn from the needle. When a different yarn is desired to be utilized, the yarn feed device secures the previously selected yarn and another yarn is selectively fed in a similar manner as the first yarn. The needle utilized includes a plurality of holes or vents angled relative to the axis of the needle.
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FIELD OF THE INVENTION
The present invention relates to silica-filled halogenated butyl elastomers, such as bromobutyl elastomers (BIIR).
BACKGROUND OF THE INVENTION
It is known that reinforcing fillers such as carbon black and silica greatly improve the strength and fatigue properties of elastomeric compounds. It is also known that chemical interaction occurs between the elastomer and the filler. For example, good interaction between carbon black and highly unsaturated elastomers such as polybutadiene (BR) and styrene butadiene copolymers (SBR) occurs because of the large number of carbon-carbon double bonds present in these copolymers. Butyl elastomers may have only one tenth, or fewer, of the carbon-carbon double bonds found in BR or SBR, and compounds made from butyl elastomers are known to interact poorly with carbon black. For example, a compound prepared by mixing carbon black with a combination of BR and butyl elastomers results in domains of BR, which contain most of the carbon black, and butyl domains which contain very little carbon black. It is also known that butyl compounds have poor abrasion resistance.
Canadian Patent Application 2,293,149 shows that it is possible to produce filled butyl elastomer compositions with improved properties by combining halobutyl elastomers with silica and specific silanes. These silanes act as dispersing and bonding agents between the halogenated butyl elastomer and the filler. However, one disadvantage of the use of silanes is the evolution of alcohol during the process of manufacture and potentially during the use of the manufactured article produced by this process. Additionally, silanes significantly increase the cost of the resulting manufactured article.
Co-pending Canadian Patent Application 2,339,080 discloses filled halobutyl elastomeric compounds containing certain organic compounds having at least one basic nitrogen-containing group and at least one hydroxyl group enhance the interaction of halobutyl elastomers with carbon-black and mineral fillers, resulting in improved compound properties such as tensile strength and abrasion (DIN).
SUMMARY OF THE INVENTION
The present invention provides a process for preparing compositions containing halobutyl elastomers, at least one mineral filler and at least one silazane compound. The invention also provides filled halobutyl elastomer compositions comprising halobutyl elastomers, at least one mineral filler and at least one silazane compound. Preferably, the present invention provides a means to produce such filled compositions without the evolution of alcohol, and at significantly reduced cost, compared to processes known in the art.
Surprisingly, it has been discovered that silazane compounds enhance the interaction of halobutyl elastomers with mineral fillers, resulting in improved compound properties such as tensile strength and abrasion (DIN). Silazane compounds are believed to disperse and bond the silica to the halogenated elastomers.
Accordingly, the present invention also provides a process, which includes mixing a halobutyl elastomer with at least one mineral filler, in the presence of at least one silazane compound, and curing the resulting filled halobutyl elastomer. According to the present invention, the resulting filled halobutyl elastomer has improved properties.
Additionally, it has been found that mixtures of silazane compounds and an additive containing at least one hydroxyl group and a functional group containing a basic amine enhance the interaction of halobutyl elastomers with mineral fillers, resulting in improved compound properties such as tensile strength and abrasion resistance (DIN).
Accordingly, the present invention also provides a process which includes mixing a halobutyl elastomer with at least one mineral filler, in the presence of at least one silazane compound and one additive containing at least one hydroxyl group and a functional group containing a basic amine, and curing the resulting filled halobutyl elastomer. The resulting composition, having improved properties, forms another aspect of the invention.
The halobutyl elastomer, which is admixed with the mineral filler and the silazane compound or the mixture of silazane compound and an additive containing at least one hydroxy group and a functional group containing a basic amine, may also be in a mixture with another elastomer or elastomeric compound. The halobutyl elastomer should constitute more than 5% of any such mixture. Preferably, the halobutyl elastomer should constitute at least 10% of any such mixture. In some cases it is preferred not to use mixtures but to use the halobutyl elastomer as the sole elastomer. If mixtures are to be used, the other elastomer may be, for example, natural rubber, polybutadiene, styrene-butadiene or poly-chloroprene or an elastomer compound containing one or more of these elastomers.
The filled halobutyl elastomer can be cured to obtain a product, which has improved properties, such as improved abrasion resistance, rolling resistance and traction. Curing can be effected with sulfur. The preferred amount of sulfur is in the range of from 0.3 to 2.0 parts by weight per hundred parts of rubber. An activator, for example zinc oxide, may also be used, in an amount in the range of from 0.5 parts to 2 parts by weight. Other ingredients, for instance stearic acid, antioxidants, or accelerators may also be added to the elastomer prior to curing. Sulphur curing is then effected in any known manner. See, for example, “Rubber Technology”, chapter 2, “The Compounding and Vulcanization of Rubber” (3 rd ed., Chapman & Hall, 1995).
Other curatives known to cure halobutyl elastomers may also be used. Such known curatives include bis dieneophiles. Suitable bis dieneophiles include m-phenyl-bis-maleinimide and m-phenylene-bis-maleimide (HVA2). Other suitable compounds that are known to cure halobutyl elastomers include phenolic resins, amines, amino acids, peroxides, zinc oxide and the like. Combinations of the aforementioned curatives may also be used.
The mineral filled halobutyl elastomer of the present invention can also be admixed with other elastomers or elastomeric compounds before it is subjected to curing with sulphur. This is discussed further below.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a graph of the stress/strain curves of filled halobutyl elastomer compounds, which contain HMDZ, according to the present invention, and to a filled halobutyl elastomer compound which does not contain HMZD.
FIG. 2 is a graph of the complex modulus/strain curves of filled halobutyl elastomer compounds, which contain HMDZ, according to the present invention, and to a filled halobutyl elastomer compound which does not contain HMZD.
FIG. 3 is a graph of the time versus the torque for filled halobutyl elastomer compounds, which contain HMDZ, according to the present invention, and to a filled halobutyl elastomer compound which does not contain HMZD.
FIG. 4 is a graph of the stress/strain curves of filled halobutyl elastomer compounds, which contain HMDZ and MEA, according to the present invention, and to a filled halobutyl elastomer compound which does not contain HMZD.
FIG. 5 is a graph of the complex modulus/strain curves of filled halobutyl elastomer compounds, which contain HMDZ and MEA, according to the present invention, and to a filled halobutyl elastomer compound which does not contain HMZD.
FIG. 6 is a graph of the stress/strain curves of filled halobutyl elastomer compounds, which contain HMDZ and MEA and were prepared on a 6″×12″ mill, according to the present invention, and to a filled halobutyl elastomer compound which does not contain HMZD.
FIG. 7 is a graph of the complex modulus/strain curves of filled halobutyl elastomer compounds, which contain HMDZ and MEA and were prepared on a 6″×12″ mill, according to the present invention, and to a filled halobutyl elastomer compound which does not contain HMZD.
FIG. 8 is a graph of the stress/strain curves of filled halobutyl elastomer compounds, which contain HMDZ and DMEA and were prepared in a Banbury mixer, according to the present invention, and to a filled halobutyl elastomer compound which does not contain HMZD.
FIG. 9 is a graph of the complex modulus/strain curves of filled halobutyl elastomer compounds, which contain HMDZ and DMEA and were prepared in a Banbury mixer, according to the present invention, and to a filled halobutyl elastomer compound which does not contain HMZD.
FIG. 10 is a graph of the stress/strain curves of filled halobutyl elastomer compounds, which contain HMDZ and DMEA and were prepared on a 6″×12″ mill, according to the present invention, and to a filled halobutyl elastomer compound which does not contain HMZD.
FIG. 11 is a graph of the complex modulus/strain curves of filled halobutyl elastomer compounds, which contain HMDZ and DMEA and were prepared on a 6″×12″ mill, according to the present invention, and to a filled halobutyl elastomer compound which does not contain HMZD.
DETAILED DESCRIPTION OF THE INVENTION
The phrase “halobutyl elastomer(s)” as used herein refers to a chlorinated or brominated butyl elastomer. Brominated butyl elastomers are preferred, and the present invention is illustrated, by way of example, with reference to bromobutyl elastomers. It should be understood, however, that the present invention extends to the use of chlorinated butyl elastomers.
Halobutyl elastomers suitable for use in the present invention include, but are not limited to, brominated butyl elastomers. Such elastomers may be obtained by bromination of butyl rubber, which is a copolymer of an isoolefin, usually isobutylene and a co-monomer that is usually a C 4 to C 6 conjugated diolefin, preferably isoprene and brominated isobutene-isoprene-copolymers (BIIR). Co-monomers other than conjugated diolefins can be used, such as alkyl-substituted vinyl aromatic co-monomers which includes C 1 -C 4 -alkyl substituted styrene. An example of a halobutyl elastomer which is commercially available is brominated isobutylene methylstyrene copolymer (BIMS) in which the co-monomer is p-methylstyrene.
Brominated butyl elastomers typically contain in the range of from 0.1 to 10 weight percent, preferably 0.5 to 5 weight percent of repeating units derived from diolefin, preferably isoprene, and in the range of from 90 to 99.9 weight percent, preferably 95 to 99.5 weight percent of repeating units derived from isoolefin, preferably isobutylene, based upon the hydrocarbon content of the polymer, and in the range of from 0.1 to 9 weight percent, preferably 0.75 to 2.3 weight percent and more preferably from 0.75 to 2.3 weight percent bromine, based upon the bromobutyl polymer. A typical bromobutyl polymer has a molecular weight, expressed as the Mooney viscosity according to DIN 53 523 (ML 1+8 at 125° C.), in the range of from 25 to 60.
A stabilizer may be added to the brominated butyl elastomer. Suitable stabilizers include calcium stearate and epoxidized soy bean oil, preferably used in an amount in the range of from 0.5 to 5 parts by weight per 100 parts by weight of the brominated butyl rubber (phr).
Examples of suitable brominated butyl elastomers include Bayer Bromobutyl 2030, Bayer Bromobutyl 2040 (BB2040), and Bayer Bromobutyl X2 commercially available from Bayer Corporation. Bayer BB2040 has a Mooney viscosity (ML 1+8@125° C.) of 39±4, a bromine content of 2.0±0.3 wt % and an approximate molecular weight of 500,000 grams per mole.
The brominated butyl elastomer used in the process of the present invention may also be a graft copolymer of a brominated butyl rubber and a polymer based upon a conjugated diolefin monomer. Co-pending Canadian Patent Application 2,279,085 is directed towards a process for preparing such graft copolymers by mixing solid brominated butyl rubber with a solid polymer based on a conjugated diolefin monomer which also includes some C—S—(S) n —C bonds, where n is an integer from 1 to 7, the mixing being carried out at a temperature greater than 50° C. and for a time sufficient to cause grafting. The bromobutyl elastomer of the graft copolymer can be any of those described above. The conjugated diolefins that can be incorporated in the graft copolymer generally have the structural formula:
wherein R is a hydrogen atom or an alkyl group containing from 1 to 8 carbon atoms and wherein R 1 and R 11 can be the same or different and are selected from hydrogen atoms or alkyl groups containing from 1 to 4 carbon atoms. Suitable conjugated diolefins include 1,3-butadiene, isoprene, 2-methyl-1,3-pentadiene, 4-butyl-1,3-pentadiene, 2,3-dimethyl-1,3-pentadiene 1,3-hexadiene, 1,3-octadiene, 2,3-dibutyl-1,3-pentadiene, 2-ethyl-1,3-pentadiene, 2-ethyl-1,3-butadiene and the like. Conjugated diolefin monomers containing from 4 to 8 carbon atoms are preferred, 1,3-butadiene and isoprene being more preferred.
The polymer based on a conjugated diene monomer can be a homopolymer, or a copolymer of two or more conjugated diene monomers, or a copolymer with a vinyl aromatic monomer.
The vinyl aromatic monomers, which can optionally be used, should be copolymerizable with the conjugated diolefin monomers being employed. Generally, any vinyl aromatic monomer, which is known to polymerize with organo alkali metal initiators, can be used. Such vinyl aromatic monomers usually contain in the range of from 8 to 20 carbon atoms, preferably from 8 to 14 carbon atoms. Examples of suitable vinyl aromatic monomers include styrene, alpha-methyl styrene, various alkyl styrenes including p-methylstyrene, p-methoxy styrene, 1-vinylnaphthalene, 2-vinyl naphthalene, 4-vinyl toluene and the like. Styrene is preferred for copolymerization with 1,3-butadiene alone or for terpolymerization with both 1,3-butadiene and isoprene.
According to the present invention, halogenated butyl elastomer may be used alone or in combination with other elastomers such as:
BR
polybutadiene;
ABR
butadiene/C 1 -C 4 alkyl acrylate copolymers;
CR
polychloroprene;
IR
polyisoprene;
SBR
styrene/butadiene copolymers with styrene
contents of 1 to 60, preferably 20 to 50 wt. %;
IIR
isobutylene/isoprene copolymers;
NBR
butadiene/acrylonitrile copolymers with
acrylonitrile contents of 5 to 60, preferably 10 to
40 wt. %;
HNBR
partially hydrogenated or completely
hydrogenated NBR; or
EPDM
ethylene/propylene/diene copolymers.
Fillers according to the present invention are composed of particles of a mineral, suitable fillers include silica, silicates, clay (such as bentonite), gypsum, alumina, titanium dioxide, talc and the like, as well as mixtures thereof.
Further examples of suitable fillers include:
highly disperse silicas, prepared e.g. by the precipitation of silicate solutions or the flame hydrolysis of silicon halides, with specific surface areas of 5 to 1000, preferably 20 to 400 m 2 /g (BET specific surface area), and with primary particle sizes of 10 to 400 nm; the silicas can optionally also be present as mixed oxides with other metal oxides such as Al, Mg, Ca, Ba, Zn, Zr and Ti;
synthetic silicates, such as aluminum silicate and alkaline earth metal silicate;
magnesium silicate or calcium silicate, with BET specific surface areas of 20 to 400 m 2 /g and primary particle diameters of 10 to 400 nm;
natural silicates, such as kaolin and other naturally occurring silica;
glass fibers and glass fiber products (matting, extrudates) or glass microspheres;
metal oxides, such as zinc oxide, calcium oxide, magnesium oxide and aluminum oxide;
metal carbonates, such as magnesium carbonate, calcium carbonate and zinc carbonate;
metal hydroxides, e.g. aluminum hydroxide and magnesium hydroxide
or combinations thereof.
Because these mineral particles have hydroxyl groups on their surface, rendering them hydrophilic and oleophobic, it is difficult to achieve good interaction between the filler particles and the butyl elastomer. For many purposes, the preferred mineral is silica, especially silica prepared by the carbon dioxide precipitation of sodium silicate.
Dried amorphous silica particles suitable for use as mineral fillers in accordance with the present invention have a mean agglomerate particle size in the range of from 1 to 100 microns, preferably between 10 and 50 microns and more preferably between 10 and 25 microns. It is preferred that less than 10 percent by volume of the agglomerate particles are below 5 microns or over 50 microns in size. A suitable amorphous dried silica has a BET surface area, measured in accordance with DIN (Deutsche Industrie Nor) 66131, of between 50 and 450 square meters per gram and a DBP absorption, as measured in accordance with DIN 53601, of between 150 and 400 grams per 100 grams of silica, and a drying loss, as measured according to DIN ISO 787/11, of from 0 to 10 percent by weight. Suitable silica fillers are commercially available under the trademarks HiSil 210, HiSil 233 and HiSil 243 available from PPG Industries Inc. Also suitable are Vulkasil S and Vulkasil N, commercially available from Bayer AG.
Mineral fillers can also be used in combination with known non-mineral fillers, such as
carbon blacks; suitable carbon blacks are preferably prepared by the lamp black, furnace black or gas black process and have BET specific surface areas of 20 to 200 m 2 /g, for example, SAF, ISAF, HAF, FEF or GPF carbon blacks; or
rubber gels, preferably those based on polybutadiene, butadiene/styrene copolymers, butadiene/acrylonitrile copolymers and polychloroprene.
Non-mineral fillers are not normally used as filler in the halobutyl elastomer compositions of the present invention, but in some embodiments they may be present in an amount up to 40 phr. It is preferred that the mineral filler should constitute at least 55% by weight of the total amount of filler. If the halobutyl elastomer composition of the present invention is blended with another elastomeric composition, that other composition may contain mineral and/or non-mineral fillers.
According to the present invention the silazane compound can have one or more silazane group, such as a disilazane. Organic silazane compounds are preferred. Suitable silazane compounds include but are not limited to hexamethyldisilazane, heptamethyldisilazane, 1,1,3,3-tetramethyldisilazane, 1,3-bis(chloromethyl)tetramethyldisilazane, 1,3-divinyl-1,1,3,3-tetramethyldisilazane, and 1,3-diphenyltetramethyl-disilazane.
Examples of additives, which give enhanced physical properties to mixtures of halobutyl elastomers, filler and organic silazanes, include proteins, aspartic acid, 6-aminocaproic acid, diethanolamine and triethanolamine. Preferably, the additive containing at least one hydroxyl group and a functional group containing a basic amine should also contain a primary alcohol group and an amine group separated by methylene bridges, which may be branched. Such compounds have the general formula HO—A—NH 2 ; wherein A is a C1 to C20 alkylene group, which may be linear or branched.
More preferably, the number of methylene groups between the two functional groups should be in the range of from 1 to 4. Examples of preferred additives include monoethanolamine and N,N-dimethyaminoalcohol.
The amount of filler to be incorporated into the halobutyl elastomer can vary between wide limits. Typical amounts of filler range from 20 parts to 250 parts by weight, preferably from 30 parts to 100 parts, more preferably from 40 to 80 parts per hundred parts of elastomer. The amount of the silazane compound is typically in the range of from 0.5 to 10 parts per hundred parts of elastomer, preferably of from 1 to 6, more preferably of from 2 to 5 parts per hundred parts of elastomer. The amount of the additive containing at least one hydroxyl group and a functional group containing a basic amine used in conjunction with the silazane compound is typically in the range of from 0.5 to 10 parts per hundred parts of elastomer, preferably of from 1 to 3 parts per hundred parts of elastomer.
Furthermore up to 40 parts of processing oil, preferably from 5 to 20 parts, per hundred parts of elastomer, may be present. Further, a lubricant, for example a fatty acid such as stearic acid, may be present in an amount up to 3 parts by weight, more preferably in an amount up to 2 parts by weight.
The halobutyl elastomer(s), filler(s) and silazane(s) or silazane/additive containing at least one hydroxyl group and a functional group containing a basic amine mixtures are mixed together, suitably at a temperature in the range of from 25 to 200° C. It is preferred that the mixing temperature be greater than 60° C., and a temperature in the range of from 90 to 150° C. is preferred. Normally the mixing time does not exceed one hour; a time in the range from 2 to 30 minutes is usually adequate. The mixing is suitably carried out on a two-roll mill mixer, which provides good dispersion of the filler within the elastomer. Mixing may also be carried out in a Banbury mixer, or in a Haake or Brabender miniature internal mixer. An extruder also provides good mixing, and has the further advantage that it permits shorter mixing times. It is also possible to carry out the mixing in two or more stages. Further, the mixing can be carried out in different apparatuses, for example one stage may be carried out in an internal mixer and another in an extruder.
The enhanced interaction between the filler and the halobutyl elastomer results in improved properties for the filled elastomer. These improved properties include higher tensile strength, higher abrasion resistance, lower permeability and better dynamic properties. These render the filled elastomers suitable for a number of applications, including, but not limited to, use in tire treads and tire sidewalls, tire innerliners, tank linings, hoses, rollers, conveyor belts, curing bladders, gas masks, pharmaceutical enclosures and gaskets.
According to the present invention, a bromobutyl elastomer, silica particles, a silazane compound or a silazane/additive containing at least one hydroxyl group and a functional group containing a basic amine mixture and, optionally, a processing oil extender are mixed on a two-roll mill at a nominal mill temperature of 25° C. The mixed compound is then placed on a two-roll mill and mixed at a temperature above 60° C. It is preferred that the temperature of the mixing is not too high, and more preferably does not exceed 150° C., since higher temperatures may cause curing to proceed undesirably far and thus impede subsequent processing. The product of mixing these four ingredients at a temperature not exceeding 150° C. is a compound which has good stress/strain properties and which can be readily processed further on a warm mill with the addition of curatives.
The filled halobutyl rubber compositions of the present invention, and preferably filled bromobutyl rubber compositions have many uses, preferably in tire tread compositions. Important features of a tire tread composition are that it shall have low rolling resistance, good traction, particularly in the wet, and good abrasion resistance so that it is resistant to wear. Compositions of the present invention display these desirable properties. Thus, an indicator of traction is tan δ at 0° C., with a high tan δ at 0° C. correlating with good traction. An indicator of rolling resistance is tan δ at 60° C., with a low tan δ at 60° C. correlating with low rolling resistance. Rolling resistance is a measure of the resistance to forward movement of the tire, and low rolling resistance is desired to reduce fuel consumption. Low values of loss modulus at 60° C. are also indicators of low rolling resistance. As is demonstrated in the examples below, compositions of the present invention display high tan δ at 0° C., low tan δ at 60° C. and low loss modulus at 60° C.
The invention is further illustrated but is not intended to be limited by the following examples in which all parts and percentages are by weight unless otherwise specified.
EXAMPLES
Description of Tests:
Abrasion resistance: DIN 53-516 (60 grit Emery paper)
Dynamic Property Testing: Dynamic testing (tan δ at 0° C. and 60° C., Loss modulus at 60° C.) were carried out using the GABO. The GABO is a dynamic mechanical analyzer for characterizing the properties of vulcanized elastomeric materials. The dynamic mechanical properties give a measure of traction with the best traction usually obtained with high values of tan δ at 0° C. Low values of tan δ at 60° C., and in particular, low loss moduli at 60° C. are indicators of low rolling resistance. RPA measurements were obtained with the use of an Alpha Technologies RPA 2000 operating at 100° C. at a frequency of 6 cpm. Strain sweeps were measured at strains of 0.1, 0.2, 0.5, 1, 2, 5, 10, 20, 50 and 90°.
Cure rheometry: ASTM D 52-89 MDR2000E Rheometer at 1° arc and 1.7 Hz
Description of Ingredients and General Mixing Procedure:
Hi-Sil 233—silica—a product of PPG
Sunpar® 2280 —paraffinic oil produced by Sun Oil
Maglite® D —magnesium oxide produced by CP Hall
The brominated butyl elastomer (in all cases commercial Bayer Bromobutyl 2030) silica, oil and silazane or silazane/additive containing at least one hydroxyl group and a functional group containing a basic amine mixture were mixed on either:
i) a tangential Banbury internal mixer operating at 77 rpm while being thermally regulated with the use of a Mokon set to 40° C. Compounds were mixed for a total of 6 minutes. The final rubber temperature ranged from 140° C. to 180° C.
ii) a 6″×12″ two-roll mill with the rolls running at 24 and 32 rpm. The mill roll was set at 25° C., with a total incorporation time of 10 minutes. The mixed compounds were then “heat treated” for a further 10 minutes with the roll temperature at 110° C. The final rubber temperature was 125° C.
Curatives were then added to the cooled sample with the mill at 25° C.
Example 1
The affect of silazane incorporation into halogenated butyl elastomer/silica compounds was investigated via the formulation of several compounds of which hexamethyidisilazane (HMDZ) was incorporated as the silazane compound. For comparison, a halogenated butyl elastomer/silica compound with no silazane was also prepared as a control compound.
Brominated isoprene isobutylene rubber (BIIR) was mixed with the silazane and 60 parts per hundred rubber (phr) of silica filler (HiSil 233) in a tangential Banbury mixer under the mixing conditions described above. Identical curative ingredients (1 phr of stearic acid, 0.5 phr of sulfur, and 1.5 phr of ZnO) were then added on a cool mill to each of the compounds. The compounds were then cured for either t c( 90)+10 minutes at 170° C. (for DIN Abrasion testing) or t c( 90)+5 minutes at 170° C. and tested. Tables 1 and 2 gives the product compositions, and physical property data for the HMDZ containing compounds and for a compound containing no filler bonding agent.
The data in Table 1 shows the effect of adding HMDZ to assist in the bonding and dispersion of the siliceous filler in the brominated butyl elastomer. The ratio M300/M100 is commonly used as a relative measure of the degree of filler reinforcement in an elastomer compound (the higher the ratio the higher the reinforcement). While the M300/M100 for compound 1d with no HMDZ (example 1d will here in be used as the control compound for the remaining examples) is 1.97 the M300/M100 values for the compounds containing HMDZ ranges from 3.76 to 4.13. (See FIG. 1 ). The value of the complex modulus (G*, MPa) at low strains obtained from RPA measurements is commonly used as a relative measure of the degree of filler reinforcement in an elastomer compound (the lower the value of G*, the higher the degree of filler dispersion). From the data in Table 1, it is clear that a significant improvement in filler dispersion is observed on the addition of HMDZ to brominated butyl rubber/silica compounds. Specifically, for the control compound, the G* value is 2934 MPa while for the compounds containing HMDZ, this value ranges from 365 to 631 MPa (See FIG. 2 ).
Importantly, the data in Table 1 also shows that the improvement in filler dispersion and bonding does not effect the overall processability of the resulting compound. On examination of the Mooney Scorch data presented in Table 1 and FIG. 3, it can be seen that the incorporation of HMDZ into these brominated butyl rubber/silica compounds significantly improves the scorch safety (i.e. increase in the t03 times).
With respect to the performance of these compounds in tires treads, tan δ values at 0° C. and 60° C. as well as loss modulus (G″, MPa) values at 60° C. are quoted. Specifically, high tan δ values at 0° C. are indicative of good traction while low values of tan δ at 60° C. and low values of G″ at 60° C. are indicative of low rolling resistance. From the data presented in Table 2, the positive effects of HMDZ on the tan δ value at 0° C. and the G″ value at 60° C. are seen. While the control compound possesses a tan δ (0° C.) of 0.23 and a G″ (60° C.) of 3.33 MPa, compounds containing HMDZ possess tan δ (0° C.) values ranging from 0.49 to 0.88 and G″ (60° C.) values ranging from 0.93 to 1.98 MPa.
Example 2
Co-pending Canadian Patent Application 2,339,080 illustrates the utility of additives containing at least one hydroxyl group and at least one substituent bearing a basic amine group in the dispersion and reinforcement of silica in halogenated butyl elastomer compounds. Given the positive effect seen through the introduction of HMDZ into halogenated butyl elastomer/silica compounds, mixtures of HMDZ and the additive containing at least one hydroxyl group and a functional group containing a basic amines of the type described above were examined. This example investigates the effect of incorporating mixtures of HMDZ and monoethanolamine (MEA) into halogenated butyl elastomer/silica compounds prepared in a Banbury internal mixer.
Brominated isoprene isobutylene rubber (BIIR) was mixed with the additives and 60 parts per hundred rubber (phr) of silica filler (HiSil 233) in a tangential Banbury mixer under the mixing conditions described above. Identical curative ingredients (1 phr of stearic acid, 0.5 phr of sulfur, and 1.5 phr of ZnO) were then added on a cool mill to each of the compounds. The compounds were then cured for either t c( 90)+10 minutes at 170° C. (for DIN Abrasion testing) or t c( 90)+5 minutes at 170° C. and tested. Tables 3 and 4 gives the product compositions, and physical property data for the HMDZ/MEA containing compounds and for a compound containing only MEA.
The data in Table 3 shows the effect of adding HMDZ and MEA to assist in the bonding and dispersion of the filler in the brominated butyl elastomer. While the M300/M100 for the control compound is 1.97, the compounds containing HMDZ and MEA possess M300/M100 values ranging from 2.79 to 4.30 (See FIG. 4 ). Additionally, a significant improvement in filler dispersion is observed on the addition of HMDZ and MEA to brominated butyl rubber/silica compounds. Specifically, for the control compound, the G* value is 2934 MPa while for the compounds containing HMDZ and MEA, this value ranges from 304 to 1609 MPa (See FIG. 5 ). The incorporation of 2.9 phr of HMDZ and 2.2 phr of MEA or 2.9 phr of HMDZ and 1.1 phr of MEA is seen to improve the degree of filler dispersion over what is observed for the compound which only contains MEA.
While the data in Table 3 suggests the addition of HMDZ into halogenated butyl elastomer/silica/MEA compounds lowers the M300/M100 values and increases the DIN abrasion volume loss, it is important to note the significant improvement in scorch safety as evidence by the increased t03 times.
From the data presented in Table 4, the positive effects of HMDZ and MEA on the tan δ value at 0° C. and the G″ value at 60° C. are seen. While the control compound possesses a tan δ (0° C.) of 0.23 and a G″ (60° C.) value of 3.33 MPa, compounds containing HMDZ and MEA possess tan δ (0° C.) values ranging from 0.43 to 0.85 and G″ (60° C.) values ranging from 1.10 to 2.39 MPa. Furthermore, compounds which contain 2.9 phr of HMDZ and 2.2 phr of MEA and compounds which contain 2.9 phr of HMDZ and 1.1 phr of MEA possess superior tan δ (0° C.) and G″ (60° C.) values than does the halogenated butyl elastomer/silica compound which only contains MEA.
Example 3
This example investigates the effect of incorporating mixtures of HMDZ and monoethanolamine (MEA) into halogenated butyl elastomer/silica compounds prepared on a 6″×12″ mill.
Brominated isoprene isobutylene rubber (BIIR) was mixed with the additives and 60 parts per hundred rubber (phr) of silica filler (HiSil 233) on a 6″×12″ mill under the mixing conditions described above. Identical curative ingredients (1 phr of stearic acid, 0.5 phr of sulfur, and 1.5 phr of ZnO) were then added to each of these compounds on a cool mill. The compounds were then cured for either t c(90) +10 minutes at 170° C. (for DIN Abrasion testing) or t c(90) +5 minutes at 170° C. and tested. Tables 5 and 6 gives the product compositions, and physical property data for the HMDZ/MEA containing compounds and for a compound containing only MEA.
The data in Table 5 shows the effect of adding HMDZ and MEA to assist in the bonding and dispersion of the filler in the brominated butyl elastomer. While the M300/M100 for the control compound is 1.97, the compounds containing HMDZ and MEA possess M300/M100 values ranging from 4.02 to 6.00. (See FIG. 6 ). Additionally, a significant improvement in filler dispersion is observed on the addition of HMDZ and MEA to brominated butyl rubber/silica compounds. Specifically, for the control compound, the G* value is 2934 MPa while for the compounds containing HMDZ and MEA, this value ranges from 256 to 538 MPa (See FIG. 7 ). The incorporation of HMDZ in conjunction with MEA is seen to improve both the degree of reinforcement (M300/M100) and of filler dispersion (G* at low strains) over what is observed for the compound which contains only MEA.
The data in Table 5 also suggests that the addition of HMDZ into halogenated butyl elastomer/silica/MEA compounds lowers the DIN abrasion volume loss when compared to both the control compound and the compound which contains only MEA.
From the data presented in Table 6, the positive effects of HMDZ and MEA on the tan δ value at 0° C. and the G″ value at 60° C. are seen. While the control compound possesses a tan δ (0° C.) of 0.23 and a G″ (60° C.) of 3.33 MPa, compounds containing HMDZ and MEA possess tan δ (0° C.) values ranging from 0.50 to 0.86 and G″ (60° C.) values ranging from 0.69 to 1.78 MPa. Furthermore, compounds which contain both HMDZ and MEA possess superior tan δ (0° C.) and G″ (60° C.) values than does the halogenated butyl elastomer/silica compound which contains only MEA.
Example 4
This example investigates the effect of incorporating mixtures of HMDZ and N,N-dimethylaminoethanol (DMAE) into halogenated butyl elastomer/silica compounds prepared in a Banbury.
Brominated isoprene isobutylene rubber (BIIR) was mixed with the additives and 60 parts per hundred rubber (phr) of silica filler (HiSil 233) in a tangential Banbury mixer under the mixing conditions described above. Identical curative ingredients (1 phr of stearic acid, 0.5 phr of sulfur, and 1.5 phr of ZnO) were then added on a cool mill to each of these compounds. The compounds were then cured for either t c(90) +10 minutes at 170° C. (for DIN Abrasion testing) or t c(90) +5 minutes at 170° C. and tested. Tables 7 and 8 give the product compositions, and physical property data for the HMDZ/DMAE containing compounds and for a compound containing only DMAE.
The data in Table 7 shows the effect of adding HMDZ and DMAE to assist in the bonding and dispersion of the filler in the brominated butyl elastomer. While the M300/M100 for the control compound is 1.97, the compounds containing HMDZ and DMAE possess M300/M100 values ranging from 2.93 to 4.27. (See FIG. 8 ). Additionally, a significant improvement in filler dispersion is observed on the addition of HMDZ and DMAE to brominated butyl rubber/silica compounds. Specifically, for the control compound, the G* value is 2934 MPa while for the compounds containing HMDZ and MEA, this value ranges from 227 to 1056 MPa (See FIG. 9 ). The incorporation of 2.9 phr of HMDZ and 3.2 phr of DMAE or 2.9 phr of HMDZ and 1.6 phr of DMAE is seen to improve the degree of filler dispersion over what is observed for the compound which contains only DMAE.
While the data in Table 7 suggests the addition of HMDZ into halogenated butyl elastomer/silica/DMAE compounds lowers the M300/M100 values and increases the DIN abrasion volume loss, it is important to note the significant improvement in scorch safety as evidence by the increased t03 times possessed by these compounds.
From the data presented in Table 8, the positive effects of HMDZ and DMAE on the tan δ value at 0° C. and the G″ value at 60° C. are seen. While the control compound possesses a tan δ (0° C.) of 0.23 and a G″ (60° C.) of 3.33 MPa, compounds containing HMDZ and DMAE possess tan δ (0° C.) values ranging from 0.45 to 0.82 and G″ (60° C.) values ranging from 0.48 to 2.31 MPa. Furthermore, compounds which contain 2.9 phr of HMDZ and 3.2 phr of DMAE or 2.9 phr of HMDZ and 1.6 phr of DMAE possess superior tan δ (0° C.) and G″ (60° C.) values than does the halogenated butyl elastomer/silica compound which contains only DMAE.
Example 5
This example investigates the effect of incorporating mixtures of HMDZ and N,N-dimethylaminoethanol (DMAE) into halogenated butyl elastomer/silica compounds prepared on a 6″×12″ mill.
Brominated isoprene isobutylene rubber (BIIR) was mixed with the additives and 60 parts per hundred rubber (phr) of silica filler (HiSil 233) on a 6″×12″ mill under the mixing conditions described above. Identical curative ingredients (1 phr of stearic acid, 0.5 phr of sulfur, and 1.5 phr of ZnO) were then added on a cool mill to each of these compounds. The compounds were then cured for either t c(90) +10 minutes at 170° C. (for DIN Abrasion testing) or t c(90) +5 minutes at 170° C. and tested. Tables 9 and 10 give the product compositions and physical property data for the HMDZ/DMAE containing compounds and for a compound containing only DMAE.
The data in Table 9 shows the effect of adding HMDZ and DMAE to assist in the bonding and dispersion of the filler in the brominated butyl elastomer. While the M300/M100 for the control compound is 1.97, the compounds containing HMDZ and DMAE possess M300/M100 values ranging from 4.41 to 6.55. (See FIG. 10 ). Additionally, a significant improvement in filler dispersion is observed on the addition of HMDZ and DMAE to brominated butyl rubber/silica compounds. Specifically, for the control compound, the G* value is 2934 MPa while for the compounds containing HMDZ and MEA, this value ranges from 245 to 742 MPa (See FIG. 11 ). The incorporation of 2.9 phr of HMDZ and 3.2 phr of DMAE or 2.9 phr of HMDZ and 1.6 phr of DMAE is seen to improve both the degree of reinforcement (M300/M100) and of filler dispersion (G* at low strains) over what is observed for the compound which contains only DMAE.
The Mooney Scorch data presented in Table 9 also illustrates the positive impact on the t03 times (increased t03 times imply improved processability) observed on addition of HMDZ to halogenated butyl elastomer/silica/DMAE compounds.
From the data presented in Table 10, the positive effects of HMDZ and DMAE on the tan δ value at 0° C. and the G″ value at 60° C. are seen. While the control compound possesses a tan δ (0° C.) of 0.23 and a G″ (60° C.) of 3.33 MPa, compounds containing HMDZ and DMAE possess tan δ (0° C.) values ranging from 0.56 to 0.86 and G″ (60° C.) values ranging from 0.42 to 1.61 MPa. Furthermore, compounds which contain 2.9 phr of HMDZ and 3.2 phr of DMAE or 2.9 phr of HMDZ and 1.6 phr of DMAE possess superior tan δ (0° C.) and G″ (60° C.) values than does the halogenated butyl elastomer/silica compound which contains only DMAE.
TABLE 1
Example
1a
1b
1c
1d
Additives
HMDZ
HMDZ
HMDZ
Control
Additives (phr)
5.8
2.9
1.45
0
STRESS STRAIN (Die C DUMBELLS, cured for tc90 + 5 min, tested @ 23° C.)
Hard. Shore A2 Inst. (pts.)
51
60
67
80
Ultimate Tensile (MPa)
18.27
18.7
17.76
11.22
Ultimate Elongation (%)
876
800
752
894
Strain (% Elongation)
Stress (MPa)
Stress (MPa)
Stress (MPa)
Stress (MPa)
25
0.6
0.86
1.2
2.1
50
0.77
1
1.25
2.02
100
1.05
1.28
1.48
1.97
200
2.02
2.49
2.79
2.62
300
4.07
5.28
5.56
3.89
300/100
3.88
4.13
3.76
1.97
DIN ABRASION (cured for tc90 + 10 min @ 170° C.)
Abrasion Volume Loss (mm 3 )
282
190
189
283
COMPOUND MOONEY SCORCH (Small rotor, tested @ 130° C.)
t Value t03 (min)
10.26
15.23
11.89
2.52
t Value t18 (min)
24.21
22.23
14.78
9.34
t Value t18 − t03 (min)
13.95
7
2.89
6.82
MDR CURE CHARACTERISTICS (tested @ 170° C., 1° arc, 1.7 Hz)
MH (dN · m)
18.08
24.27
28.77
32.04
ML (dN · m)
3.71
5.12
8.28
17.86
Delta t′50—t′10 (min)
4.36
3.92
3.19
8.33
RPA PAYNE EFFECT (tested @ 100° C., 30 cpm)
G*
G*
G*
G*
Strain %
kPa
kPa
kPa
kPa
0.28
365.97
466.02
631.4
2934
0.98
413.78
520.18
721.14
3134
TABLE 2
Example
1a
1b
1c
1d
Additives
HMDZ
HMDZ
HMDZ
Control
Additives (phr)
5.8
2.9
1.45
0
GABO (cured for tc90+5 @ 170° C.,
test run from −100° C. to 100° C.)
Tan δ @ 0° C.
0.88
0.68
0.49
0.23
Tan δ @ 60° C.
0.23
0.21
0.17
0.08
G″ @ 60° C. (MPa)
0.93
1.37
1.98
3.33
TABLE 3
Example
2a
2b
2c
2d
2e
Additives
MEA
HMDZ/MEA
HMDZ/MEA
HMDZ/MEA
HMDZ/MEA
Additives (phr)
2.2
2.9/2.2
2.9/1.1
1.45/1.1
1.45/0.55
STRESS STRAIN (Die C DUMBELLS, cured for tc90 + 5 min, tested @ 23° C.)
Hard. Shore A2 Inst. (pts.)
71
56
53
70
70
Ultimate Tensile (MPa)
14.88
15.91
15.66
16.29
16.05
Ultimate Elongation (%)
340
567
821
909
1036
Strain (% Elongation)
Stress (MPa)
Stress (MPa)
Stress (MPa)
Stress (MPa)
Stress (MPa)
25
1.46
0.773
0.689
1.3
1.34
50
1.75
0.999
0.854
1.34
1.3
100
2.71
1.63
1.13
1.58
1.4
200
6.66
4.08
2.14
2.79
2.23
300
12.79
7.01
3.89
4.73
3.91
300/100
4.72
4.30
3.44
2.99
2.79
DIN ABRASION (cured for tc90 + 10 min @ 170° C.)
Abrasion Volume Loss (mm 3 )
232
303
341
292
291
COMPOUND MOONEY SCORCH (Small rotor, tested @ 130° C.)
t Value t03 (min)
0.09
3.02
7.14
6.27
11.35
t Value t18 (min)
1.71
4.38
11.89
10.81
21.92
t Value t18 − t03 (min)
1.62
1.36
4.75
4.54
10.57
MDR CURE CHARACTERISTICS (tested @ 170° C., 1° arc, 1.7 Hz)
MH (dN · m)
34.61
21.64
18.67
32.74
31.44
ML (dN · m)
9.24
3.71
3.35
6.63
7.4
Delta t′50—t′10 (min)
2.64
4.3
5.98
3.51
4.04
RPA PAYNE EFFECT (tested @ 100° C., 30 cpm)
Strain
G*
G*
G*
G*
G*
%
kPa
KPa
kPa
kPa
kPa
0.28
676.38
304.68
374.25
1555
1609.8
0.98
717.37
346.05
381.16
1691.1
1720.9
TABLE 4
Example
2a
2b
2c
2d
2e
Additives
MEA
HMDZ/MEA
HMDZ/MEA
HMDZ/MEA
HMDZ/MEA
Additives (phr)
2.2
2.9/2.2
2.9/1.1
1.45/1.1
1.45/0.55
GABO (cured for tc90 + 5 @ 170° C., test run from −100° C. to 100° C.)
Tan δ @ 0° C.
0.50
0.82
0.85
0.45
0.43
Tan δ @ 60° C.
0.11
0.20
0.23
0.14
0.14
G″ @ 60° C. (MPa)
1.61
1.13
1.10
2.32
2.39
TABLE 5
Example
3a
3b
3c
3d
3e
Additives
MEA
HMDZ/MEA
HMDZ/MEA
HMDZ/MEA
HMDZ/MEA
Additives (phr)
2.2
2.9/2.2
2.9/1.1
1.45/1.1
1.45/0.55
STRESS STRAIN (Die C DUMBELLS, cured for tc90 + 5 min, tested @ 23° C.)
Hard. Shore A2 Inst. (pts.)
80
55
55
67
65
Ultimate Tensile (MPa)
17.4
17.45
20.5
17.57
20.63
Ultimate Elongation (%)
405
387
498
588
624
Strain (% Elongation)
Stress (MPa)
Stress (MPa)
Stress (MPa)
Stress (MPa)
Stress (MPa)
25
2.42
0.8
0.79
1.28
1.21
50
3.04
1.2
1.09
1.41
1.37
100
5.54
2.28
1.92
1.88
1.79
200
10.78
6.69
5.69
3.98
3.77
300
14.86
13.07
11.52
7.56
7.75
300/100
2.68
5.73
6.00
4.02
4.33
DIN ABRASION (cured for tc90 + 10 min @ 170° C.)
Abrasion Volume Loss (mm 3 )
263
181
159
213
174
COMPOUND MOONEY SCORCH (Small rotor, tested @ 130° C.)
t Value t03 (min)
3.9
0.09
3.47
4.13
10.98
t Value t18 (min)
5.32
0.95
6.71
6.34
16.73
t Value t18 − t03 (min)
1.42
0.86
3.24
2.21
5.75
MDR CURE CHARACTERISTICS (tested @ 170° C., 1° arc, 1.7 Hz)
MH (dN · m)
45.93
17.5
20.06
32.39
31.04
ML (dN · m)
12.83
4.86
4.52
7.18
7.83
Delta t′50—t′10 (min)
1.21
3.4
3.42
2.45
2.55
RPA PAYNE EFFECT (tested @ 100° C., 30 cpm)
Strain
G*
G*
G*
G*
G*
%
kPa
kPa
kPa
kPa
kPa
0.28
1577.2
256.55
255.86
590.43
537.89
TABLE 6
Example
3a
3b
3c
3d
3e
Additives
MEA
HMDZ/MEA
HMDZ/MEA
HMDZ/MEA
HMDZ/MEA
Additives (phr)
2.2
2.9/2.2
2.9/1.1
1.45/1.1
1.45/0.55
GABO (cured for tc90 + 5 @ 170° C., test run from −100° C. to 100° C.)
Tan δ @ 0° C.
0.28
0.84
0.86
0.50
0.56
Tan δ @ 60° C.
0.08
0.16
0.18
0.14
0.14
G″ @ 60° C. (MPa)
2.91
0.69
0.88
1.78
1.59
TABLE 7
Example
4a
4b
4c
4d
4e
Additives
DMAE
HMDZ/DMAE
HMDZ/DMAE
HMDZ/DMAE
HMDZ/DMAE
Additives (phr)
3.2
2.9/3.2
2.9/1.6
1.45/1.6
1.45/0.8
STRESS STRAIN (Die C DUMBELLS, cured for tc90 + 5 min, tested @ 23° C.)
Hard. Shore A2 Inst. (pts.)
64
54
54
69
70
Ultimate Tensile (MPa)
20.73
18.26
17.79
17.45
15.97
Ultimate Elongation (%)
428
585
715
756
924
Strain (% Elongation)
Stress (MPa)
Stress (MPa)
Stress (MPa)
Stress (MPa)
Stress (MPa)
25
1.13
0.734
0.74
1.26
1.32
50
1.47
1.05
1
1.36
1.34
100
2.48
1.73
1.5
1.7
1.54
200
7.29
4.42
3.39
3.37
2.6
300
13.91
8.21
6.41
5.96
4.51
300/100
5.61
4.21
4.27
3.51
2.93
DIN ABRASION (cured for tc90 + 10 min @ 170° C.)
Abrasion Volume Loss (mm 3 )
156
161
204
236
243
COMPOUND MOONEY SCORCH (Small rotor, tested @ 130° C.)
t Value t03 (min)
0.32
4.86
7.17
7.85
13.6
t Value t18 (min)
4.7
7.4
12.93
13.13
25.93
t Value t18 − t03 (min)
4.38
2.54
5.76
5.28
12.33
MDR CURE CHARACTERISTICS (tested @ 170° C., 1° arc, 1.7 Hz)
MH (dN · m)
29.01
22.74
21.3
32.91
32.19
ML (dN · m)
8.91
5.17
4.38
5.79
5.74
Delta t′50—t′10 (min)
2.08
3.06
4.87
3.72
4.67
RPA PAYNE EFFECT (tested @ 100° C., 30 cpm)
Strain
G*
G*
G*
G*
G*
%
kPa
kPa
kPa
kPa
kPa
0.28
504.7
227.53
267.66
806.94
1056.2
0.98
531.22
266.22
280.89
901.32
1149.6
TABLE 8
Example
4a
4b
4c
4d
4e
Additives
DMAE
HMDZ/DMAE
HMDZ/DMAE
HMDZ/DMAE
HMDZ/DMAE
Additives (phr)
3.2
2.9/3.2
2.9/1.6
1.45/1.6
1.45/0.8
GABO (cured for tc90 + 5 @ 170° C., test run from −100° C. to 100° C.)
Tan δ @ 0° C.
0.70
0.82
0.84
0.56
0.45
Tan δ @ 60° C.
0.10
0.11
0.14
0.14
0.14
G″ @ 60° C. (MPa)
0.80
0.48
0.66
1.61
2.31
TABLE 9
Example
5a
5b
5c
5d
5e
Additives
DMAE
HMDZ/DMAE
HMDZ/DMAE
HMDZ/DMAE
HMDZ/DMAE
Additives (phr)
3.2
2.9/3.2
2.9/1.6
1.45/1.6
1.45/0.8
STRESS STRAIN (Die C DUMBELLS, cured for tc90 + 5 min, tested @ 23° C.)
Hard. Shore A2 Inst. (pts.)
68
53
53
67
65
Ultimate Tensile (MPa)
20.81
22.32
21.53
20.96
20.26
Ultimate Elongation (%)
494
552
559
569
614
Strain (% Elongation)
Stress (Mpa)
Stress (MPa)
Stress (MPa)
Stress (MPa)
Stress (MPa)
25
1.36
0.73
0.75
1.33
1.24
50
1.61
1.04
1.04
1.58
1.4
100
2.52
1.74
1.73
2.39
1.89
200
7.03
5.25
5.15
5.76
4.09
300
13.04
11.4
10.97
10.96
8.33
300/100
5.17
6.55
6.34
4.59
4.41
DIN ABRASION (cured for tc90 + 10 min @ 170° C.)
Abrasion Volume Loss (mm 3 )
171
218
245
161
154
COMPOUND MOONEY SCORCH (Small rotor, tested @ 130° C.)
t Value t03 (min)
0.12
11.5
20.18
8.89
26.49
t Value t18 (min)
5.23
23.24
>30
20.97
30
t Value t18 − t03 (min)
5.11
11.74
NR
12.08
NR
MDR CURE CHARACTERISTICS (tested @ 170° C., 1° arc, 1.7 Hz)
MH (dN · m)
35.72
19.81
19.55
34.52
30.34
ML (dN · m)
10.39
5.81
5.12
9.17
9.09
Delta t′50—t′10 (min)
2.61
8.09
8.49
3.79
3.98
RPA PAYNE EFFECT (tested @ 100° C., 30 cpm)
Strain
G*
G*
G*
G*
G*
%
kPa
kPa
kPa
kPa
kPa
0.28
672.69
245.56
270.49
646.73
742.46
0.98
724.12
251.58
275.81
769.07
842.28
TABLE 10
Example
5a
5b
5c
5d
5e
Additives
DMAE
HMDZ/DMAE
HMDZ/DMAE
HMDZ/DMAE
HMDZ/DMAE
Additives (phr)
3.2
2.9/3.2
2.9/1.6
1.45/1.6
1.45/0.8
GABO (cured for tc90+5 @ 170° C., test run from −100° C. to 100° C.)
Tan δ @ 0° C.
0.55
0.86
0.86
0.56
0.56
Tan δ @ 60° C.
0.11
0.11
0.13
0.13
0.15
G″ @ 60° C. (MPa)
1.40
0.42
0.53
1.46
1.61
Although the invention has been described in detail in the foregoing for the purpose of illustration, it is to be understood that such detail is solely for that purpose and that variations can be made therein by those skilled in the art without departing from the spirit and scope of the invention except as it may be limited by the claims.
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The present invention provides a process for preparing a filled halobutyl elastomer, which comprises mixing a halobutyl elastomer, mineral filler and a silazane compound or mixture of a silazane compound and an additive which contains at least one hydroxyl group and at least one substituents which bears a basic amine group, and curing the filled elastomer with sulfur or other curative systems. The present invention has the advantages of (a) not evolving alcohol either during the manufacture or subsequent use of the article manufactured from the compound, (b) improving the scorch safety of filled halobutyl elastomer compounds which employ silica as the mineral filler and a the additive containing at least one hydroxyl group and a functional group containing a basic amine as a dispersing aid and (c) significantly reducing the cost of the compound compared to analogous compounds currently known in the art.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a method and a device for displacing and storing brake fluid for a hydraulic brake system of a vehicle.
[0003] 2. Description of Related Art
[0004] In a hydraulic brake system of a vehicle, a brake pedal is mostly actuated by the driver and, with the optional assistance of a brake booster, mechanically displaces a piston in a master brake cylinder, at whose outlets a hydraulic unit is connected. In this manner, brake fluid is introduced into the hydraulic unit (e.g., ESP or ABS) and directed to the wheel brake cylinders. There, the introduced volume increases the brake pressure and causes braking action by pressing the brake pads onto the brake disks.
[0005] In modern brake systems, brake calipers are often provided with an increased gap between brake pads and brake disks to reduce the friction of the brake and thereby minimize fuel consumption. This gap is set in a purely mechanical manner and is a function of, inter alia, the time of brakeless travel. For this reason, the size of the gap is not always the same. In the case of manipulating the brake pedal, this results in, inter alia, a pedal play up to the point of closing the gap, which is a function of the driving situation; and therefore, this results in a non-reproducible relationship between pedal travel and total braking torque. The pedal characteristic may be different from braking instance to braking instance.
[0006] In addition, such a gap reduces the dynamic response of a braking action, since in the event of manipulating the brake pedal, any existing gap causes the braking action to still not occur immediately.
BRIEF SUMMARY OF THE INVENTION
[0007] The present invention provides a method and a device for displacing and storing brake fluid for a hydraulic brake system of a vehicle. In this context, the brake system has at least one hydraulic accumulator, at least one brake booster and at least one brake circuit, the brake booster being developed in such a manner, that even without action of the driver, actuation of the brake booster allows a volume of brake fluid to be automatically displaced.
[0008] The essence of the present invention is that:
brake fluid is displaced into the hydraulic accumulator and stored, by automatic actuation of the brake booster; and at least a portion of the stored brake fluid is emptied by the hydraulic accumulator into the brake circuit as a function of the operating state of the brake system.
[0011] In a specific embodiment of the present invention, a hydraulic accumulator is integrated into the brake system, the hydraulic accumulator being hydraulically connected to the master brake cylinder and the wheel brakes, in which, for example, the gap mentioned at the outset is supposed to be closed. This connection may be broken by a switchable valve. A controllable, electronic brake booster, which is advantageously a component of the brake system, may be controlled in such a manner, that it exerts force on the piston of a master brake cylinder without assistance from the driver and consequently displaces a volume in the direction of a brake circuit. If one breaks the hydraulic connection to the brake circuit and opens the hydraulic connection to the hydraulic accumulator, then volumes of brake fluid may be introduced into the accumulator. By closing the hydraulic connection, the introduced volume may be held there. If one opens the connection again, then the volume is released again and enters into the brake circuit. Now, if the brake circuit has at least one wheel brake having a gap between the brake pad and the brake disk, then at least one portion of the stored brake fluid may be discharged by the hydraulic accumulator into the brake circuit to reduce the gap. In this manner, the variable gap may be closed, irrespective of the initial size of the gap, by introducing a volume of brake fluid. In this context, it is particularly provided that the gap be reduced until a pressure increase in the brake circuit is detected and/or the driver lowers the position of the brake pedal, the pedal travel being monitored with the aid of a pedal-travel sensor.
[0012] In an advantageous refinement of the present invention, a first interrupting device is provided,
by the closing of which, the brake pressure in the at least one brake circuit is independent of an actuation of the brake booster; and which is open during the emptying. In addition, a second interrupting device may be provided, by the opening of which a hydraulic connection between the at least one brake circuit and the hydraulic accumulator is rendered possible, and which is configured as follows:
The second interrupting device is opened during the emptying of the at least one portion of the stored brake fluid. The second interrupting device is closed during the storage.
[0018] Alternatively or in addition to the reduction of the gap, it may also be provided that at least a portion of the stored brake fluid be emptied by the hydraulic accumulator into the brake circuit to increase the dynamics of the pressure build-up in the brake circuit.
[0019] In particular, it is provided that the present invention's displacing of brake fluid into the hydraulic accumulator in driving situations, in which the driver does not brake and/or braking is unlikely, takes place, in particular, as a function of the position of a brake pedal.
[0020] Furthermore, the displacing of brake fluid into the hydraulic accumulator may take place as a function of a measured accumulator pressure, the accumulator pressure being measured by a pressure sensor at hand.
[0021] The emptying of the hydraulic accumulator according to the present invention may take place
on the basis of driver behavior, in particular, changing the position of and/or the contact state of a brake pedal ( 101 ) of an accelerator pedal and/or on the basis of driving situations, particularly in the case of braking assistance, in which the brake pressure exceeds the degree predetermined by the brake pedal, or in the case of emergency braking.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] FIG. 1 schematically shows the part of a brake system in which the hydraulic accumulator is integrated, as well as the devices which are necessary for the controlled charging and emptying of the same.
[0025] FIG. 2 shows the method steps for charging the hydraulic accumulator.
[0026] FIG. 3 shows the method steps for emptying the hydraulic accumulator.
DETAILED DESCRIPTION OF THE INVENTION
[0027] The device according to the present invention is represented in FIG. 1 . In response to manipulation by the driver, an actuating element 101 of a brake system, in the form of a brake pedal, is mechanically able to displace a first of two pistons 103 of a tandem master brake cylinder 102 . In addition to the braking force exerted by the driver, first piston 103 may be acted upon by an assisting force that is produced by a brake booster 104 .
[0028] In the exemplary embodiment represented here, the brake booster is a controllable, electromechanical brake booster. In the following, the starting point is a controllable, electromechanical brake booster, which is controlled by a control unit (not drawn in, here) and is able, with the assistance of an electric motor, to exert a force on input piston 103 of tandem master brake cylinder 102 . Further specific embodiments of a brake booster, such as a controllable, pneumatic brake booster, are easily conceivable.
[0029] A second piston of the tandem master brake cylinder is also displaced by the combination of brake pedal manipulation and brake force amplification. The displacement of pistons 103 and 105 results in the displacement of brake fluid into the brake circuits respectively connected to the two outlets of tandem master brake cylinder 106 and 107 .
[0030] The volume displaced into the brake circuits produces an increase of pressure in the wheel brake cylinders connected to the brake circuits. The pressure increase at the wheel brake cylinders causes the brake pads to be pressed against the brake disks, and thus, produces a braking action.
[0031] In the case of an increased gap between the brake pads and brake disks, it is of interest to compensate for this and to prevent free play in the pedal. For this reason, in a variant of the brake system according to the present invention, a switchable hydraulic accumulator 108 is connected to tandem master brake cylinder 102 at its output side; in the method of the present invention, the switchable hydraulic accumulator being developed and operated in such a manner, that it is able to displace a volume into the at least one, connected brake circuit and thereby build up pressure at the wheel brake cylinders.
[0032] In the specific embodiment sketched here, the hydraulic accumulator is connected to outlet 107 of tandem master brake cylinder 102 via a switchable exhaust valve 109 . In a preferred exemplary embodiment, valve 409 is a controllable solenoid valve and is controlled by a control unit that is not drawn in, here. The control unit may be separate, as well as provided in the form of the control unit of the brake booster or of a hydraulic accumulator connected to outlets 106 and 107 .
[0033] In the embodiment sketched here, hydraulic accumulator 108 is made up of a chamber 110 , a piston 111 , as well as a compressible element 112 , which is able to exert a force on the piston, in opposition to the compression, and, thus, to store energy and release it again by displacing the piston.
[0034] Of course, other specific embodiments of the hydraulic accumulator are conceivable, for example, a diaphragm-type accumulator, a metallic expansion-bellows accumulator or a piston accumulator.
[0035] According to the depicted exemplary embodiment of the present invention, the hydraulic accumulator is charged by brake booster 104 , via tandem master brake cylinder 102 , when valve 109 is open. In order to prevent the occurrence of a braking action, a valve 113 is provided, which breaks the hydraulic connection between the tandem brake master cylinder and the wheel brakes while the accumulator is charged. This valve may either be additionally integrated into the brake circuit as a component, or be already integrated, thus, e.g., in the form of intake valves at the individual wheel brakes. The volume of brake fluid is held in the accumulator by closing valve 109 , and discharged by reopening valve 109 . In this context, in some instances, the valve position of the intake valves of a connected hydraulic unit is to be taken into consideration.
[0036] In the first specific embodiment of the present invention, the switchable hydraulic accumulator is operated to reduce the gap at at least one wheel brake of a brake system.
[0037] To that end, in a first step, while the driver is not braking, the input piston 103 of tandem master brake cylinder 102 is displaced by actuation of brake booster 104 ; and consequently, when valve 109 is open and input valves of the hydraulic unit (not drawn in) are closed, a volume of brake fluid is displaced out of outlets 106 and 107 , into the hydraulic accumulator. This causes compression of compressible element 112 , and the accumulator receives brake fluid. As soon as the accumulator is filled, valve 109 is closed. Brake booster 104 is reset and is therefore available for braking.
[0038] The level of the accumulator pressure and, therefore, the fluid level of the accumulator may be measured by a pressure sensor already present, such as the inlet pressure sensor or the brake-circuit pressure sensor.
[0039] The decision of when/if the accumulator is charged/may be charged may be linked, for example, to the accelerator position. If the accelerator position exceeds a limiting value, then the accumulator is charged.
[0040] For the braking feel, it is important to maintain the relationship between pedal travel and total braking torque of the vehicle, regardless of the gap present at the start of the braking. To that end, in the case of braking by the driver, directly after a manipulation of the brake pedal by the driver is sensed and the connection of the master brake cylinder to the reservoir (not drawn in) is thereby broken, valve 109 is opened, and accumulator 108 displaces a volume of brake fluid into the brake system and, in this manner, provides for a pressure increase at the wheel brake cylinders, which results in an at least partial reduction of the gap.
[0041] In order to reduce the gap completely, a suitable amount of brake fluid from the hydraulic accumulator must be introduced into the brake system. Valve 109 is left open until contact of the brake pads with the disks is detected. This contact may be detected in light of a pressure increase characteristic of the contact of the brake pads.
[0042] A further option for detecting the contact is available in the case of braking with the aid of the electromechanical brake booster, by detecting a characteristic increase in the motor load torque of the servomotor of the brake booster as a function of the pedal travel.
[0043] The pressure increase may be determined by a pressure sensor in at least one brake circuit of the hydraulic system, the brake circuit being connected to the hydraulic accumulator.
[0044] The pedal travel may be ascertained with the aid of a pedal-travel sensor, or using the motor position of the servomotor of the brake booster. The motor load torque may be derived, for example, from the motor current and/or from the rotational speed of the motor. In the case of speed control or position control of the motor, the current increases proportionally to the motor load torque; in the case of current control or torque control, a higher motor load torque results in a lower rotational speed of the motor.
[0045] Of course, other methods of detecting the contact are conceivable.
[0046] As soon as contact of the brake pads with the brake disks is detected, valve 109 is closed.
[0047] Consequently, it is ensured:
that the introduction of the volume of brake fluid from the hydraulic accumulator to reduce the gap does not trigger a braking action, or triggers only a slight braking action; that a brake pressure higher than that desired by the driver (through the pedal actuation selected by him or her) is not set at the wheel brake cylinders; and that therefore, the driver senses the desired relationship between pedal travel and total braking torque.
[0051] It is equally possible to close the valve when the driver lowers the position of the brake pedal.
[0052] In an alternative embodiment of the method according to the present invention, the hydraulic accumulator is emptied to increase the dynamic braking response, thus, for example, in the case of automatic emergency braking without driver participation, or in the case of braking with the aid of a braking assistance function, e.g., initiating full braking on the basis of rapid brake pedal actuation by the driver. To that end, valve 109 is controlled in such a manner, that it is opened and the hydraulic accumulator releases a volume of brake fluid. In order to supply the displaced volume from the accumulator to the connected brake circuit, valve 113 is opened. In the case of such braking, the brake pressure is increased with the aid of the controllable brake booster, with the aid of the pressure build-up via the volume injection of the hydraulic accumulator, as well as, optionally, with the aid of an active pressure build-up of a traction control system.
[0053] Valve 109 remains open until the accumulator pressure is lower than the pressure in the brake circuit. The accumulator pressure may either be measured by an additional sensor or calculated from the starting pressure (after charging) and the valve opening time.
[0054] Irrespective of the application of the method or the purpose of the application, the method is made up of two basic elements, the charging of the hydraulic accumulator, as well as the emptying of the hydraulic accumulator.
[0055] In FIGS. 2 and 3 , these two main components are exemplarily shown for one brake circuit, but may easily be expanded to two brake circuits.
[0056] Charging method, shown in FIG. 2 :
[0057] 201 . Closing valve 113
[0058] 202 . Opening valve 109
[0059] 203 . Controlling the brake booster in such a manner, that the input piston of the master cylinder is displaced by brake booster 104 , and a volume of brake fluid is thereby displaced into hydraulic accumulator 108
[0060] 204 . Monitoring the pressure build-up in the hydraulic accumulator, using a pressure sensor
[0061] 205 . Closing valve 109 as soon as hydraulic accumulator 108 is charged
[0062] 206 . Resetting brake booster 104 .
[0063] Emptying method, shown in FIG. 3 (solid line: braking situation; dashed line: emergency braking/braking assistant)
[0064] 301 . Starting situations:
[0065] a. Braking Situation: Sensing brake pedal actuation by the driver
[0066] b. Braking assistance case/emergency braking
[0067] 302 . Opening valve 113
[0068] 303 . Opening valve 109 up to a break-off condition
[0069] a. Accumulator pressure<brake circuit pressure
[0070] b. Detection of contact of the brake pads
[0071] 304 . Closing valve 109
[0072] As an alternative to step 204 , during the charging, although it is not shown graphically, if the pressure sensor is situated on the side of valve 113 facing away from the accumulator, in a first substep, the starting pressure may be recorded, in a second substep, valve 113 is closed, and in a third substep, by controlling the travel of brake booster 104 , a volume is injected until the accumulator is full. In this alternative, the fluid level may be ascertained with the aid of the starting pressure and a pressure-versus-volume characteristic curve of the accumulator.
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In a method for displacing and storing brake fluid for a hydraulic brake system of a vehicle which brake system has at least one hydraulic accumulator, at least one brake booster and at least one brake circuit, the brake booster is configured in such a manner, that even without an action of the driver, actuation of the brake booster allows a volume of brake fluid to be automatically displaced. The brake fluid is displaced into the hydraulic accumulator and stored, by automatic actuation of the brake booster, and at least a portion of the stored brake fluid is emptied by the hydraulic accumulator into the brake circuit as a function of the operating state of the brake system.
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[0001] This patent claims priority from and incorporates by reference the provisional U.S. patent application Ser. No. 60/646825, filed Jan. 25, 2005.
BACKGROUND OF THE INVENTION
[0002] The present invention relates to the field of valves, more specifically to the field of reed valves. U.S. Pat. Nos. 6,454,545 B1 (Ikeda, 2002), 6,231,315 B1 (Ikeda, 2001), 5,454,397 (Miszczak, 1995), 5,355,910 (Gies, 1994), 5,226,796 (Okamoto, 1993), 5,186,475 (Kawai, 1993), 4,714,416 (Sano, 1987), 4,696,263 (Boyesen, 1987), 4,580,604 (Kawaguchi, 1986), 3,994,319 (Airhart, 1976), 3,983,900 (Airhart, 1976), 3,939,876 (Lundvik, 1976), 2,906,281 (Pillote, 1959), 2,881,795 (Waldenmaier, 1959), 2,864,394 (Hempel, 1958), and 2,476,320 (Paulus, 1949) disclose various valves comprising various cantilever or reed components. None of the cited patents disclose or claim the apparatus of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0003] The structure and operation of the invention will become apparent upon reading the following detailed description of the preferred embodiment and upon reference to the accompanying drawings in which like details are labeled with like identification numbers throughout. The drawings do not conform to a consistent scale.
[0004] FIG. 1 is a cross sectional view of an air-conditioning compressor in which the preferred embodiment of the present invention bulkhead insert and reed stabilizer are installed.
[0005] FIG. 2 is a cross-sectional view of the front bulkhead of a state-of-the-art air-conditioning compressor that does not embody the present invention.
[0006] FIG. 3 is a cross-sectional view of the front bulkhead of the compressor of FIG. 1 in which the preferred embodiment of the present invention bulkhead insert and reed stabilizer are installed.
[0007] FIG. 4 is a cross-sectional view of the preferred embodiment of the present invention bulkhead insert.
[0008] FIG. 5 is an isometric view of the cantilever portions of a reed valve, its integrated annular support structure, and two integrated tabs with alignment holes. The entire FIG. 5 structure is herein referred to as a “reed.”
[0009] FIG. 6 is a plan view of a reed retainer.
[0010] FIG. 7 is a sectional view of one of the curved radial arms of a reed retainer.
[0011] FIG. 8 is a plan view of a gasket.
[0012] FIG. 9 is a plan view of a valve plate.
[0013] FIG. 10 is a plan view of a suction reed.
[0014] FIG. 11 is a cross-sectional view of a cylinder block assembly.
[0015] FIG. 12 is a plan view of a shaft.
[0016] FIG. 13 is an isometric view of a shaft, two valve plates, a gasket, a suction reed, a discharge reed, a discharge reed retainer, a piston, four alignment pins, and the preferred embodiment of the present invention bulkhead insert.
[0017] FIG. 14 is a rotated view of FIG. 13 .
[0018] FIG. 15 is a cross-sectional view of a reed stabilizer.
[0019] FIG. 16 is a large-scale view of the front bulkhead area of FIG. 1 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0020] The inventors present herein the best mode for carrying out the present invention in terms of its preferred embodiment, depicted within the aforementioned drawings. Herein, the preferred embodiment of the present invention will be considered to have a front end and a rear end. The end of the preferred embodiment where splined end 25 of shaft 12 in FIGS. 1 and 12 protrudes from front bulkhead 2 will be referred to as the “front,” and the opposite end will be referred to as the “rear.” “Outboard” herein refers to the direction radially outward from the longitudinal axis of shaft 12 .
[0021] A reed valve is a valve having a cantilever that is anchored, pinned, clamped, or otherwise held at one end, with the opposite end free to undergo displacement in the process of opening and closing a port or ports that provide ingress or egress of gases, fluids, and substances that have some fluidic characteristics including, but not limited to, grain, sand, and pellets. As is common in the many industries that employ valves, “reed” is used herein to denote the cantilever portion of a reed valve. Although it can be used in any application calling for a reed valve, the preferred embodiment of the present invention is incorporated in an air-conditioning compressor commonly understood in the automotive industry.
[0022] FIG. 1 shows cylinder blocks 1 assembled between front bulkhead 2 and rear bulkhead 3 of an automotive compressor 100 . Within the interior cavities of cylinder blocks 1 are at least one piston 10 and a swash plate 9 . A drive belt, chain, gear, or other transfer means transfers automotive engine energy to splined end 25 (see FIG. 12 ) of shaft 12 , and shaft 12 in turn imparts rotational motion to a swash plate 9 that is attached to shaft 12 . Motion of swash plate 9 converts rotary motion of shaft 12 into linear reciprocating motion of piston 10 .
[0023] That reciprocating motion of piston 10 in a cylinder provides the refrigerant compression required in a cooling system. A cooling cycle includes stages of compression and expansion of a refrigerant gas. At the end of a compression stage, the pressure of the compressed gas forces valves to open, thus providing routes by which the gas can escape the compression chambers and proceed to the expansion part of the system where the desired cooling is achieved. The cantilever portion of a valve that provides for such gas transfer is called a discharge reed. Front discharge reed 7 and rear discharge reed 26 can be seen in FIG. 1 . Front discharge reed 7 and rear discharge reed 26 are free to bend as far as front and rear reed retainers 8 and 24 , respectively, permit.
[0024] FIGS. 2 and 3 show, respectively, a portion of a prior art air-conditioning compressor, and a like portion of a compressor equipped with the present invention. FIG. 2 shows that the prior art anchor point of reed 14 is a distance (D 1 )/ 2 from the centerline of shaft 12 . FIG. 3 shows that the anchor point of the present invention discharge reed 7 is a shorter distance (D 2 )/ 2 from the shaft centerline. The result is a present invention reed of length R 2 ( FIG. 3 ) greater than the prior art reed length R 1 ( FIG. 2 ). Because the bending stress imposed on a flexed cantilever is inversely proportional to the cantilever length, longevity of discharge reed 7 will be greater than that of reed 14 for the same displacement, cross-section, and material. MARKS' STANDARD HANDBOOK FOR MECHANICAL ENGINEERS 5-24 (Theodore Baumeister ed., McGraw-Hill 8th ed. 1978).
[0025] As shown in FIGS. 3, 4 , and 16 , insert 13 is the present invention that provides for the increased length of discharge reed 7 . After shaft seal 11 is pressed into front bulkhead 2 , O-ring 19 and insert 13 are pressed into front bulkhead 2 . A sealant may be used to enhance the sealing capability of seal 11 and/or insert 13 . As illustrated in FIGS. 3, 4 , and 16 , O-ring 15 is then fitted into circumferential cavity 27 in insert 13 .
[0026] As shown in FIG. 16 , front discharge reed 7 is placed concentrically on top of the surface of front valve plate 4 marked with the letter “F” (to denote “front”; see FIG. 9 ), and front discharge reed retainer 8 is placed on top of front discharge reed 7 so that reed and reed retainer alignment holes 28 and 29 , respectively, align with the two alignment holes in front valve plate 4 . As shown in FIG. 16 , the small diameter rear end D 3 of reed stabilizer 17 (see FIG. 15 ) is slip-fitted into the concentric inner holes in reed retainer 8 , reed 7 , and front valve plate 4 , and then crimped. This riveting process creates a subassembly consisting of front reed retainer 8 , front reed 7 , front valve plate 4 , and reed stabilizer 17 .
[0027] Next, front gasket 5 , shown in FIGS. 1 and 8 , is installed on the side of front valve plate 4 marked with the letter “F,” shown in FIGS. 1, 9 , 13 , and 14 , so that front gasket 5 and front valve plate 4 are concentric, and holes 32 in gasket 5 align with holes 31 in valve plate 4 . The subassembly consisting of front reed retainer 8 , front reed 7 , front valve plate 4 , and reed stabilizer 17 is then installed so that gasket 5 is against front bulkhead 2 , stabilizer 17 is against O-ring 15 , and gasket holes 32 and valve plate holes 31 align with pins 34 (see FIGS. 13 and 14 ) pressed into alignment holes (not shown) in front bulkhead 2 . A second set of pins (not shown) penetrates holes 28 and 29 in front discharge reed 7 and front reed retainer 8 , respectively, and the mating alignment holes in front valve plate 4 . Front suction reed 20 , shown in FIGS. 1 and 10 , is then concentrically installed against valve plate 4 using pins 34 and holes 33 for alignment.
[0028] Front suction reed 20 , shown in FIG. 10 , in the described compressor featuring the preferred embodiment of the present invention, is a thin, flat, spring steel stamping partially comprising five integral lollipop shaped suction reeds 6 (see FIG. 10 ) that each open to admit uncompressed refrigerant gas into a compression chamber as the piston in that chamber moves away from top dead center. Like the discharge reeds, the suction reeds are cantilevers, but in the described compressor design they are subjected to significantly less bending stress than are the discharge reeds. The present invention is not employed in the design of the suction reeds of the described compressor, but could be employed in a design in which suction reed valves are radially deployed around a shaft or some other central feature of a machine.
[0029] FIG. 11 shows cylinder block assembly 300 , which includes shaft 12 , swash plate 9 , piston 10 , thrust washer and bearing assemblies 18 for swash plate retention, shaft needle bearings 16 , and cylinder blocks 1 . O-rings (not shown) are fitted in circumferential grooves 36 and 37 in the front and rear faces, respectively, of cylinder blocks 1 . Cylinder block assembly 300 is installed concentrically with front bulkhead 2 and against front valve plate 4 so that splined end 25 of shaft 12 protrudes through the center holes of front valve plate 4 , gasket 5 , front discharge reed 7 , front reed retainer 8 , insert 13 , shaft seal 11 , and front bulkhead 2 .
[0030] Rear suction reed 21 (see FIG. 1 ), a duplicate of front suction reed 20 , is then installed on the front side of rear valve plate 22 , and is aligned with pins 35 shown in FIGS. 13 and 14 . Rear valve plate 22 is installed against the O-ring in groove 37 of the rear face of cylinder block assembly 300 . Rear discharge reed 26 , a duplicate of front discharge reed 7 , is installed against rear valve plate 22 . Rear reed retainer 24 , a duplicate of front reed retainer 8 , is then installed over shaft 12 and against rear discharge reed 26 .
[0031] Utilizing receiver 19 (see FIG. 13 ), rear reed retainer 24 and rear discharge reed 26 are secured to rear valve plate 22 . Gasket 23 , the mirror image of gasket 5 (see FIG. 1 ) is concentrically installed on the rear side of rear valve plate 22 , which is marked with the letter “R” (not shown). Finally, rear bulkhead 3 is installed over shaft 12 and bolted to cylinder block assembly 300 and front bulkhead 2 with bolts 30 .
[0032] In the described compressor featuring the preferred embodiment of the present invention, many variations are feasible. The O-rings such as O-rings 15 and 19 in FIG. 16 could be gaskets. In the preferred embodiment, discharge reeds 7 and 26 are shaped like flowers with petals, but they could have the shape of a star, or any other shape resembling a disc with radiating arms, and they could be constructed of materials other than metal. Reed retainers 8 and 24 could also be shaped like a star, or any other disc having radiating arms. Reed retainers 8 and 24 could also be simple discs. Insert 13 , front discharge reed 7 , and front reed retainer 8 are not required to be separate pieces, and their compositions are not limited to any particular material. In a tradeoff between parts count and total compressor weight, reed stabilizer 17 could be eliminated with a more substantial bulkhead. The present invention is not limited to use in compressors; it can also be incorporated in any number of machines that require valves situated around the circumference of a shaft.
[0033] It will be apparent to those with ordinary skill in the relevant art having the benefit of this disclosure that the present invention provides an apparatus for improving the longevity of prior art reed valves by decreasing the bending stress on the reeds of such valves during operation. It is understood that the forms of the invention shown and described in the detailed description and the drawings are to be taken merely as currently preferred examples, and that the invention is limited only by the language of the claims. The drawings and detailed description presented herein are not intended to limit the invention to the particular embodiments disclosed. While the present invention has been described in terms of one preferred embodiment, it will be apparent to those skilled in the art that form and detail modifications can be made to the described embodiment without departing from the spirit or scope of the invention.
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An apparatus for increasing the longevity of reed valves. Machines such as automotive air conditioning compressors operate with a centrally-located rotating shaft that requires lubricant seals. Assembly of such machines with access for installation of one or more shaft seals commonly dictates an annular cavity between the shaft outer diameter and the housing inner diameter. For reed valves radially deployed around the shaft, the result is an anchor point that, coupled with the commercial need for minimum overall machine diameter, restricts the allowable length of the valve reeds. A cylindrical insert that fits in the annular cavity provides for an anchor point close to the shaft, and a clamping device that anchors the reed to a retainer and its valve plate permits the use of longer reeds that offer enhanced life.
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This invention relates to a device for assisting the opening of a door, and particularly to such a device where the door to be opened is subjected to pressure above atmospheric pressure and which would be difficult to open against such pressure.
BACKGROUND
It is common to provide spring or air cushion devices which operate to open or close doors, but there are situations where a door is subjected to pressures which make opening the door by hand very difficult or impossible. One such situation is the fire escape stairwell which is commonly contructed in multi-story buildings. Such stairwells extend between floors of the building and have doors to each of the floors. A main function of such stairwells is to provide an escape for occupants on a floor in the event of a fire, and at the same time prevent the spreading of a fire between floors.
More recently it has been the practice to provide an air blower which in the event of a fire alarm will create a pressure in the chamber defined by the stairwell so that when the door to the stairwell is opened on any floor on which there is a fire the draft will be from the interior toward the exterior of the chamber rather than from the floor into the stairwell. The effect of this is to keep the fire from entering the stairwell and passing to other floors.
One difficulty with such an arrangement is that the pressure generated by the blower is applied to the inside of the door and it is difficult or impossible to move the door by hand about its hinges into the stairwell to open the door. Further, it is necessary that the door be opened and closed normally in the absence of any fire alarm.
I have set myself to the problem presented by a situation such as that above described and have devised apparatus and methods which will assist in the opening of the door when the pressure is applied but which will allow the normal opening and closing of the door without interference when the pressure is not being applied.
DETAILED DESCRIPTION
One embodiment of my invention is illustrated in the accompanying drawings in which
FIG. 1 is a schematic elevational view of a stairwell which connects the floors of a building and in which my improved device has been installed;
FIG. 2 is an enlarged elevational view of apparatus connected to a door of the stairwell in accordance with my invention, the view being taken as seen from line 2--2 of FIG. 1; and
FIG. 3 is a plan view of the apparatus shown in FIG. 2.
As illustrated in FIG. 1 the stairwell here shown provides a chamber A within the boundary of walls 11 and 12 and the ceiling 13. This chamber connects with the first floor through door 14, with the second floor through door 15, and with the third floor through door 16. An open stairway 17 leads from the first to the second floor and then to the third floor.
A fire alarm system B is provided and this is arranged as in well known systems to provide an electrical signal when on any floor someone acts to actuate the alarm.
The blower C is sensitive to the fire alarm signal and in response to this signal begins to operate and generate air pressure in chamber A which pressure extends throughout the chamber and against each of doors 14, 15 and 16. This pressure operates to create a draft of air from the inside toward the exterior of chamber A when either of doors 14 to 16 is opened, and so prevents entrance of fire from any floor into the stairwell.
To compensate for the effect of such pressures on the doors I provide mechanism D which is sensitive to the signal produced by the alarm system and which will urge the doors toward open position when such signal is received. In FIG. 1 this mechanism is shown only as applied to door 15 on the second floor, but may be applied to each of the first or third floor doors in the same way.
In the embodiment illustrated, mechanism D includes a vertical track 19 in wall 11 in which a weight 20 is disposed. For easy adjustment weight 20 is composed of several discs which are secured together by the fastening bolts 20a. To support weight 20 I provide the solenoid 21 in which is contained the slidable bolt or detent 22. The solenoid is made secure with the wall and the detent is associated with a spring 22a which presses it to its extended position where its end portion is beneath the weight 20, as shown in FIG. 2.
A cable 23 is connected with weight 20 at its top side. This cable extends over pulley 27 fastened to the wall, and thence to the front edge portion of the door 15 where the other end of the cable is attached to the eyepiece 24 in the door. The arrangement is such that when the solenoid 21 is actuated the bolt 22 is withdrawn to a position where it no longer extends beneath the weight 20 and therefore no longer supports this weight, allowing the weight to pull on the cable 23 thus urging the door 15 toward open position as shown in dotted lines in FIG. 3.
When the detent 22 is thus withdrawn the weight may move downwardly within the track 19 as the door is opened. I prefer that the cord 23 be long enough so that when the door is closed the weight 20 will be drawn up to the position in which the detent 22 is even with and is depressed by the weight 20, but not so long that when the door is closed the detent will have passed the weight 20 and be projected on the underside of this weight.
To prevent the weight 20 from striking the bottom of the track with force I provide the spring 25 at the bottom of the track which serves to cushion the descent of the weight and prevent the otherwise sudden shock which would result. The spring 25 may be positioned at any desired location along track 19 so that the urge toward open position of the door need not operate after the door has been opened to a prededetermined degree, which suitably may be that degree that permits a person to pass through the doorway.
Suitably the detent 22 may be beveled on the lower side of its forward end so that when the alarm has passed and the pressure within the chamber returns to normal, the door may simply be closed, which serves to raise weight 20 in its track, the contact of the beveled portion of the detent with the weight serving to withdraw the detent to allow the weight to pass.
A small auxiliary weight 20b which is much lighter than weight 20 is attached to cord 23 on the right hand side of pulley 27 (as shown in FIG. 2). When the door is closed as above described the weight 20 will draw the cord taut raising weight 20b, then the operator may pull on the cord to raise the weight to a further extent at which time the weight passes completely by the detent 22 and the detent is projected under the weight in this cocked position. When the operator then releases the cord the weight 20b descends to take up slack in the cord and keep the cord taut between the door 15 and the partition 19.
Also I provide a spring 18 which is disposed between the weight 20 and the bracket 18a which is attached to a track 19. This spring 18 is arranged to cushion the ascent of the weight 20 to the position shown in FIG. 2, and so prevent the slamming of the door when it is closed during the application of pressure on the inside of the chamber.
I prefer that the weight 20 be not sufficient to open the door when the weight is released, but only sufficient to compensate or partially compensate for the urge of the added pressure within the chamber toward the door to close it. In this condition the door will remain closed until a person exerts at least some pressure against the door to open it. Adjustment of the weight to accomplish this condition is easily made by adding or removing weight sections 20a.
To review the sequence of operation of the improved apparatus, when an alarm is made a signal is produced which serves to start the blower C in operation thus producing a pressure within chamber A. This signal operates also through electrical connections 26 to actuate the solenoid 21 which withdraws detent 22 from its position in which it supports weight 20. The force of weight 20 is then applied to cable 23 to door 15, tending to urge the door toward open position. But if the force of weight 20 is not sufficient to overcome the spring which normally functions to close the door plus the force of the added air pressure, the door will not then open. However, the door will open easily when anyone pushes against it. In this condition the force of the weight compensates or partially compensates for the effect on the door of the added air pressure due to the operation of blower C.
The weight 20 descends in its track as the door 15 is opened. When the weight contacts the spring 25 its movement is gradually brought to a stop, and any further opening of the door is governed only by the normal operation of the door.
When the emergency has passed and the blower is stopped and the alarm control brought to normal there is no longer an actuating signal and the door may be manually closed allowing the detent 22 to assume its original position in which it supports weight 20. In this condition the door may be opened and closed normally without interference from the special compensating mechanism D.
It may be further observed that spring 25 serves not only to prevent the crashing of weight 20 at the bottom of the track when the door is opened, but serves also to assist in starting the door from open toward closed position. This is especially helpful since when the door is open there will be little or no pressure exerted against the interior of the door due to the operation of the blower C.
While only one embodiment of my invention has been illustrated and described in detail it will be apparent to those skilled in this art that the invention may take many and varied forms and all such forms and structures are to be considered as within the spirit of the invention and contained within the scope of the appended claims.
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Apparatus for assisting the opening of a door when the door is subjected to added air pressure tending to hold the door closed, the apparatus including means operable when the pressure comes to be applied for urging the door toward opened position thus compensating or partially compensating for the effect of the added air pressure. Preferably, such means includes a weight and means which when actuated releases the weight to cause the weight to be applied to urge the door to an open position.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This disclosure relates to and claims the benefit of the filing date of commonly-owned, U.S. Provisional Patent Application No. 62/220,612, filed Sep. 18, 2015, the entire contents and disclosure of which is incorporated by reference as if fully set forth herein.
FIELD OF THE INVENTION
[0002] The present invention relates to improvements for DC power supplies having a three-phase transformer, e.g., of the 12-step or 24-step configuration, and specifically an apparatus for such DC power supplies that provides improved features such as: current limiting for the entire transformer, rectifiers and load; limiting of power inrush currents during voltage application or supply turn on; and also provides EMI filtering.
BACKGROUND
[0003] FIG. 1 illustrates a schematic diagram of a conventional three-phase, 12 step (pulse) transformer rectifier power supply 10 . The conventional 12 step transformer rectifier power supply 10 shown is designed to provide lower harmonic AC input current and relatively high power factor for DC outputs. However, these existing designs are deficient in that, secondary voltages produced are not inherently current limit protected, and separate circuits need to be employed to protect against primary transformer failure or secondary circuit electrical failures or short circuits.
[0004] From FIG. 1 , a three phase input voltage, e.g., at 50 Hz, 60 Hz or 400 Hz can typically be applied to a three phase transformer with Delta and Wye secondaries adjusted in turns for equal voltage output to two 3-phase rectifiers with each rectified secondary being placed in parallel through balancing inductors to a common load, the voltage so derived is usable by electronic loads. The Wye transformer secondary voltage phase shift with respect to the corresponding Delta secondary is 15 degrees, and hence the ‘step’ input current waveform with 360 degrees/30=12 steps or input current pulses. Similarly a 24 step (pulse) transformer would contain primary Delta-Wye interconnected windings and corresponding secondary winding yielding an input current waveform with 360 degrees/15=24 steps or input current pulses. Since this waveform has twice as many steps, it more closely approximates a sinusoidal input current and will yield 5-6% harmonic current. However since abrupt changes in the current are still present the EMI spectrum is large, and no overload protection is provided for the high power, or low impedance transformer, that is failure of a rectifier or shorted circuit on the load will require fuses and or circuit interrupt switches. In addition turn inrush current is not limited, unless a specific inrush current limiter is added.
[0005] FIG. 2 depicts a plot of an input current waveform 20 at any of the three line phase lines of the conventional 12 step (pulse) transformer rectifier power supply (e.g., a 48 Volt, 2 KW load) in an uncorrected power supply system that produces input harmonic currents exceeding 10% which is undesirable for most current power systems. Most military-grade power systems require less than 5% limits on harmonic current.
[0006] In FIG. 1 , the supply 10 includes a three phase transformer with separate Delta and Wye secondaries, two full wave rectifiers connected trough balancing inductors to a common load. The source may be a three phase commercial power line such as the 110-125 volt 50-60 HZ or 400 HZ available from a generator. The common parallel secondary D.C. Voltage is then filtered by output capacitor Co and used by the electronic loads. The Delta transformer Primary to Delta transformer secondary voltage phase remains a zero phase shift while the Wye secondary phase shift with respect to the Delta primary is 30 degrees, after rectification and paralleling with supply loading the input ‘step’ or pulse current waveform is generated.
[0007] This output voltage from power supply is a suitable low voltage supply for any of a number of electronic equipment applications, such as computer systems, medical instrumentation, telephone switching systems, machine control systems, or other apparatus employing semiconductor devices or integrated circuitry or that requires supply voltages.
[0008] By way of example, however, the typical efficiency of such prior art power supplies may exceed 85% for 425 volt outputs and 80% for 48 volt outputs, but with relatively low power factors for reasons discussed herein with reference to FIG. 2 .
SUMMARY
[0009] There is provided an apparatus and circuit enhancement for an AC to DC power supply that provides high efficiency of power conversion, reduction of line harmonic current while achieving near unity power factor.
[0010] The apparatus and circuit enhancements may be provided for a 12-step (pulse) or 24-step (pulse) configured transformer design for a DC power supply.
[0011] The apparatus and circuit enhancements for the AC to DC power supply further limits in-rush currents, such as exhibited at device turn-on, provides short circuit protection to the power supply, and enhances filtering of electromagnetic interference (EMI).
[0012] In one embodiment, the apparatus and circuit enhancement comprises a series resonant LC circuit including a series connected passive nonlinear inductor (L) and capacitor element (C) at each transformer phase input to provide an adjustable impedance which is current dependent to enhance the performance of regulated DC power supplies. This enhancement reduces the need for complex 24 step (pulse) transformers by reducing the current levels to below 2% at harmonic frequencies while providing almost unity power factor using a simple 12 step transformer.
[0013] In addition, the apparatus and circuit enhancement including the series nonlinear resonant LC circuit for the DC power supply also provides enhanced electromagnetic interference (EMI) filtering due to harmonic current spectrum reduction.
[0014] Thus, in one aspect there is provided an AC to DC power supply. The AC to DC power supply comprises: an n-step or pulsed power transformer rectifier configured to receive a 3-phase current from a connected 3-phase unregulated AC power source, the n-step or pulsed power transformer rectifier power supply having respective inputs associated with a respective phase, and the power supply including at least a primary transformer winding, and a Delta connected secondary transformer and a Wye connected secondary transformer, each Delta and Wye connected secondary transformer operatively coupled to the n-step or pulsed power transformer rectifier and having windings in parallel to provide a DC voltage; a passive circuit at each respective input of a respective phase, the passive circuit comprising a nonlinear resonant series connected LC circuit wherein L is inductor having an inductance and C is a capacitor having a capacitance, the inductance in combination with the capacitance of values reducing odd harmonic frequency current components from the line current drawn by the power supply in response to a load being placed on the AC to DC power supply, the inductance in combination with the capacitance having values that set the LC circuit near resonance and below the fundamental frequency of the 3-phase current; and wherein the power supply odd harmonic current components from the line current are reduced to less than approximately 2% cent of an uncorrected value to thereby reduce electromagnetic interference while achieving a power factor value of greater than about 0.98 at less than about 1% loss in line operating input voltage.
[0015] In a further aspect, there is provided a method of operating an AC to DC power supply having an n-step or pulsed power transformer rectifier configured to receive a 3-phase current from a connected 3-phase unregulated AC power source, the n-step or pulsed power transformer rectifier power supply having respective inputs associated with a respective phase, and the power supply including at least a primary transformer winding, and a Delta connected secondary transformer and a Wye connected secondary transformer, each Delta and Wye connected secondary transformer operatively coupled to the n-step or pulsed power transformer rectifier and having windings in parallel to provide a DC voltage output. The method comprises: providing at each respective input of a respective phase a nonlinear resonant series LC circuit wherein L is inductor having an inductance and C is a capacitor having a capacitance, an inductance value and capacitance value of the nonlinear resonant series LC circuit configured to achieve near resonance and below a fundamental frequency of the 3-phase current; connecting a power supply load to an output of the AC to DC power supply; and reducing, based on the configured nonlinear resonant series LC circuit, the AC to DC power supply odd harmonic frequency current components from the line current drawn by the power supply having the connected power supply load, wherein the odd harmonic frequency current components from the line current are reduced to less than approximately 2% cent of an uncorrected value to thereby reduce electromagnetic interference while achieving a power factor value of greater than about 0.98 at less than about 1% loss in line operating input voltage.
[0016] In addition, during power supply turn on, the input current surge drawn by the transformer or load, results in an impedance increase in the non-linear LC circuit thus limiting the inrush current. Similarly, short circuit on the secondary due to rectifier or load failure results in input current limiting.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0017] Other aspects, features and advantages of the present invention will become more fully apparent from the following detailed description, the appended claims, and the accompanying drawings in which similar elements are given similar reference numerals.
[0018] FIG. 1 illustrates a schematic diagram of a conventional uncorrected three-phase, 12 step (pulse) transformer rectifier power supply 10 ;
[0019] FIG. 2 illustrates an example plot depicting an input current waveform at any phase of the three phase line drawn by the conventional 12-step power supply 10 of FIG. 1 ;
[0020] FIG. 3 illustrates the passive circuit elements L and C of the series nonlinear resonant LC circuit in each phase of the input to the three phase transformer in a power supply 100 to provide the current harmonic reduction; and
[0021] FIG. 4 illustrates an example plot depicting an input current waveform 150 at any phase of the three phase line drawn by the enhanced DC power supply 100 having the series nonlinear resonant LC circuit at the phase inputs to provide the corrected line current in accordance with one embodiment.
DETAILED DESCRIPTION
[0022] Referring to FIG. 3 , in one embodiment, there is provided a DC to AC power supply apparatus 100 having circuitry 102 for improving the harmonic current for a 12 step or pulse transformer, while improving the power factor, providing short circuit current limiting for rectifier failure as well as inrush current limiting. In addition, any electromagnetic interference (EMI) generated is reduced, since the input current is near sinusoidal at the generator frequency. The use of this apparatus 100 with the least complex 12 step transformer also improves the reliability of the power supply, while generating the benefits described herein and reduces the need for complex 24 step (pulse) transformer.
[0023] Particularly according to an embodiment of the present invention, the circuit 102 , e.g., a harmonic current correction circuit, includes a nonlinear inductor and capacitor, the former being electrically connected in series with the capacitor, and the same (repeating) circuit is placed in each phase between the source and the uncorrected power supply input. For a rated load the impedance introduced as function of frequency per phase is |Z|. For this circuit, a series R L C circuit per phase as shown in FIG. 3 , the series connection of inductor and capacitor, exhibits a magnitude of impedance (|Z|) according to:
[0000] |Z|=R+ωLj+ 1/(ω Cj )
[0000] where ωL is the inductive reactance component (|X l |) and 1/ωC is the capacitive reactance component (|X c |) of the impedance and R the resistance.
[0024] Impedance |Z|=√{square root over ((R 2 +(X l −X c ) 2 ))} is present to current flow from the source. If X l =X c then the loss due to line current flow at the fundamental frequency is I AC 2*R, and can be minimized by design. In one example embodiment, use of an inductor L and capacitor C near resonance but below the fundamental frequency achieves efficiency of greater than 99.5%, the |Z| being low at the generator fundamental frequency less than an ohm. While increasing |Z| with frequency reduces harmonic current amplitudes that would flow due to the transformer Delta-Wye secondary rectifier loading. The uncorrected line current, for each phase, can be represented by its Fourier Series as follows:
[0000]
i
θ
(
t
)
=
∑
n
=
1
,
3
,
5
,
7
,
9
∞
i
(
t
)
sin
(
w
o
n
t
+
θ
)
[0000] where θ is a transformer phase, i(t)=∫i 1 (t)sin(w o nt) are the Fourier coefficients; and I RMS is the line current: I RMS =√{square root over ((I 1 2 +I 3 2 +I 5 2 +I 7 2 + . . . +I n 2 ))} where I 1 =RMS value of the fundamental current; and the line current=I RMS =I 1 when all harmonics are 0.
[0025] From the above equations, it is can be seen that the harmonic current is reduced as impedance to these higher frequency components is increased. It should also be noted that the flux in the core of L is a function of I AC , that provides a mechanism to support the current limiting.
[0026] Thus, referring to FIG. 3 , the circuit 102 including Inductance L and C are designed and selected at a value calculated to attenuate the odd harmonics that otherwise distort the current I AC from the AC power line. The harmonics are attributable principally the ‘step’ waveform approximation to a sin wave input current. Particularly, by proper selection of the value of inductance L and C, the odd harmonic currents may be reduced to less than approximately 2% of their uncorrected value.
[0027] From the above the inductor and capacitor have a magnitude of impedance |Z| related to the square root of (R 2 +(X l −X c ) 2 ), if X l =X c then the loss due to line current flow at the fundamental frequency is I AC 2*R, and can be minimized by design, e.g., by use of an inductor and capacitor having combined impedance near resonance but below this frequency. Efficiency of greater than 99.5% is demonstrated, i.e., the |Z| is low at the generator fundamental frequency. While increasing |Z| with frequency reduces harmonic current amplitudes that would flow due to the power supply input rectifier and bulk storage capacitor. The uncorrected line current can be represented by its Fourier Series. The harmonic current is reduced as impedance to these higher frequency components is increased.
[0028] FIG. 4 shows a greatly improved generator line current, total harmonic distortion of less than 2% demonstrated at about 2.0 KWatt loads where LC resonates near the power line frequency.
[0029] In essence, this circuit exploits the variable impedance characteristics of the LC circuit apparatus. Design of L assures that less than 1% of the line range is sacrificed, to produce a power factor of 0.99 or better for normal line currents. The flux in L by design is determined by the line current, L can be designed to be reduced in value as the line current is increased beyond the corresponding full load supply current thus moving the circuit away from the resonant fundamental frequency with C. The increased impedance of this circuit will then limit the alternating current (AC) line current.
[0030] Thus, in one aspect, the present invention provides a circuit to the 12 step (or 24-step or greater) transformer power supply which:
[0031] 1) Limits in-rush current during voltage turn on or transients;
[0032] 2) Provides short circuit current protection for T 1 should there be a shorted load or shorted secondary components;
[0033] 3) Reduces EMI circuit current spectrum generation; and
[0034] 4) Improves harmonic current to less than 2%, and achieves increased power factor as a result of the linear use of this LC circuit.
[0035] In view of FIG. 3 , the present invention thus provides a simple, low cost circuitry for enhancing the power factor of such switching regulator or electronic voltage power supplies.
[0036] In one embodiment, a power factor improvement ranging from 1-2% has been achieved using the presently preferred embodiments described herein, which comprises a linear current transformer and a capacitor, at the front end input section of the power supply for direct connection to the AC power line. These improvements are achieved at least in part by the effect of this circuit 102 to enhance the input waveform to the power supply, reduce harmonics attributable to other circuitry within the power supply, and enhance the load demand.
[0037] Referring to FIG. 3 , the preferred embodiment of the harmonic current reduction and power factor correction circuit 102 includes a linear inductor of inductance L and capacitor of capacitance C connected in a series fashion between each phase of the source voltage and each phase of the power supply input. Non-linear inductance L and capacitance C are designed and selected for values designed to attenuate the odd harmonics that otherwise distort the current IAC from the AC power line (the power line input being illustrated in FIG. 2 as a waveform). The harmonics are attributable principally to the step approximation of the transformer rectified Delta and Wye outputs. By proper selection of the value of inductance L the odd harmonic currents may be reduced to less than approximately 2% cent of their uncorrected value, at an AC power line frequency ranging from 47 Hz to 65 or 380 Hz-420 Hz.
[0038] The result is an input current to the power supply having a virtually distortion free sinusoidal characteristic as shown in the example waveform 150 of FIG. 4 .
[0039] The capacitor C of the correction circuit is selected to have a value suitable to provide the reactive power (volt amperes) demanded by the load presented by power supply. The circuit voltage drop V 1 which is proportional to its impedance at the power line frequency. (i.e., the demand current of the load represented by the power supply). Specifically, the voltage drop by the circuit is I AC *|Z| at the fundamental source frequency. With the inductive reactance=X l and the capacitance reactance=X c , and with the quantity X l −X c approaching zero, the voltage drop is I AC *R where R is essentially the loss in L.
[0040] Thus, an efficiency of 99.5% with a loss of less than 1% of the operating line range of the power supply is achieved for this circuit, while producing a power factor of greater than 0.98 for the power supply.
[0041] Further noteworthy results were achieved using the present invention with a Switching Power, Inc. Boeing model BX-2000 power supply. The supply tested was loaded to 2 KW at 60 HZ. Data was recorded with and without the present invention.
[0042] The uncorrected power supply 10 of FIG. 1 yielded greater than 10% input harmonic current.
[0043] Table 1 illustrates performance of an example operation of the BX-2000 Power Supply configured with the nonlinear resonant series LC circuit and connected with a 2 KW output load, and drawing AC line current input as shown in FIG. 4 :
[0000]
TABLE 1
Freq
Vin
Iin
ATHD
Output Load
(Hz)
(Vrms)
(Irms)
P.F.
(%)
(Vdc/A)
58.2
115.66
11.1
0.999
~0.80
46.99 V/42.7 A
60.0
115.63
11.1
0.999
~0.80
46.97 V/42.7 A
61.8
115.63
11.1
1.00
~0.80
43.91 A/42.7 A
Single
Harmonics
Ch1(%)
Ch2(%)
Ch3(%)
% AH03
0.50
0.51
0.20
% AH05
0.47
0.54
0.35
% AH07
0.16
0.28
0.17
% AH09
0.07
0.25
0.10
% AH11
1.24
1.10
1.00
% AH13
0.70
0.90
0.90
% AH15
0.04
0.06
0.06
[0044] In addition the introduction of the impedance |Z| in each phase results in a maximum input current, due to secondary transformer short circuit or rectifier failure of Vac/|Z|, thus providing by proper design of L and C the claimed overload protection.
[0045] According to an example test implementation, a current maximum of 50% above full load current was observed in short circuit of the output, simulating worst case failure of the transformer, rectifier or load short circuit.
[0046] In addition the introduction of the impedance |Z| of the harmonic current correction circuit limits the input inrush current during supply turn on. Data observed indicated a 100% reduction in in-rush currents on supply random AC input voltage application at peak of any phase voltage during power application. Currents as high as 100 A peak were mitigated to 50 A peak with the circuit described in reference to FIG. 3 .
[0047] In addition, reducing the input current harmonic levels to less than 1% reduces the EMI spectrum, reducing the filter design requirements. The lack of ‘step’ high frequency input current edges implies reduced electromagnetic spectrum, that along with no high frequency carrier or modulator for reducing harmonic current through the use of an ‘active current limit’ circuit yields lower overall, low and high frequency conducted and radiated EMI spectrum.
[0048] Although an example of the present invention have been shown and described, it would be appreciated by those skilled in the art that changes might be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents.
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Circuit and apparatus for improving operating features characteristics of DC power supplies implementing three Phase transformer devices of the type such as 12-step and 24-step transformers. The circuit and apparatus reduces harmonic AC input current while providing almost unity power factor for DC power supply outputs intended for aircraft or marine applications where size and weight are concerns. The circuit includes a passive series connected nonlinear resonant LC circuit connected at each phase of the input to the three phase transformer With the three phase transformer having the added series nonlinear resonant LC circuit, the power supply is enhanced with current limiting for the entire transformer, rectifier and load, due to load shorting, input voltage transients, transformer winding short circuit or rectifier failure. Further, such apparatus provides limiting of power inrush currents during voltage application or turn on, while also providing EMI filtering.
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FIELD OF THE INVENTION
The present invention relates to a blade assembly of a blender
DESCRIPTION OF PRIOR ART
Conventional blenders usually comprise two layers of blades attached to the rotor to form a cross and provided on the bottom of the blending container. The plain cross shape of the blade assembly limits the stirring range and cutting ability. Therefore, modification has been made by bending the tips of the first-layer blade upwardly and the tips of the second-layer blade downwardly to improve both stirring range and cutting ability of the blender.
However, during the mixing or crushing process, the plain design of said improved tip-bending blade makes the first-layer blade cutting the content mostly and only a fewer portion is processed by the second-layer blade, lowering the efficiency of the blender. Thus, to increase the efficiency of the blender and to shorten the processing time has become the main objective of the present invention.
Further, when processing hard object, such as crushing ice, the friction with the blades increases the power consumption of the blender. Therefore, to reduce the friction with the blades without affecting its processing ability has become another objective of the present invention.
SUMMARY OF THE INVENTION
To solve foregoing disadvantages, a blade assembly of a blender consists essentially of a first and a second blade ( 3 , 4 ), having an square axial hole ( 38 , 47 ) provided on each thereof, a screw ( 6 ) which can pass said axial holes ( 38 , 47 ) and engages with a receiving hole ( 11 ) on a drive shaft ( 1 ), a seat ( 2 ) corresponds with said drive shaft ( 1 ), and a gear ( 5 ) provided on a bottom of the seat ( 2 ). Said first blade ( 3 ) comprising a cutting edge ( 31 ) on a side and a spine ( 32 ) on an another side and said second blade ( 4 ) comprising a cutting edge ( 41 ) on a side and a spine ( 42 ) on an another side, characterized in that:
Said first blade ( 3 ) comprises of a flat portion ( 33 ) having said axial hole ( 38 ) in an center, a wing portion ( 34 ) extended respectively from a left and right side of said flat portion ( 33 ) and a tip portion ( 35 ) extended upwardly from a distal end of each wing portion ( 34 ); each wing portion ( 34 ) is inclined upwardly by an upward first angle (θ 1 ), each tip portion ( 35 ) is set perpendicular with axis Y by a second angle (θ 2 ) and an edge ( 30 ) of said flat portion ( 33 ) where connecting to said wing portion ( 34 ) is inclined by a third angle (θ 3 ). Said wing portion ( 34 ) is also lifted by a lifting forth angle (θ 4 ) and said tip portion ( 35 ) is inclined backwardly by a fifth angle (θ 5 ).
Said second blade ( 4 ) comprising of a flat portion ( 43 ) having said axial hole ( 47 ) in an center and a wing portion ( 44 ) extended respectively from a left and right side of said flat portion ( 43 ); each wing portion ( 44 ) is inclined downwardly by an downward sixth angle (θ 6 ) and an edge ( 40 ) of said flat portion ( 43 ) where connecting to said wing portion ( 44 ) is inclined by a seventh angle (θ 7 ).
By elevating the wing portion ( 34 ) with the first angle (θ 1 ) and the cutting edge with the fourth angle (θ 4 ), the angled wing portion ( 34 ) of the first blade ( 3 ) can lead the content crushed by the first blade ( 3 ) passing downwardly and be processed by the second blade ( 4 ), increasing the efficiency and shortening the processing time. The vertical cutting tip ( 35 ) can bring the content precipitated in the bottom of the container toward the upper portion and also stabilize the blade.
The bending second blade ( 4 ) can create a turbulent flow, allowing the content cycling between both first and second blade ( 3 , 4 ), blending to finer particles. The waving-designed cutting edges ( 31 , 41 ) of the first and second blades ( 3 , 4 ) can cut the fiber of the food or fruit with efficiency.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a perspective view of the blade assembly according to the invention.
FIG. 2 is an exploded view of the blade assembly.
FIG. 3 is a cross sectional view of the blade assembly.
FIG. 4 illustrates a front, a top and a side view of the first blade of the invention.
FIG. 5 illustrates a front, a top and a side view of the second blade of the invention.
FIG. 6 illustrates a front, a top and a side view of another embodiment of the second blade of the invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
The preferred embodiments of the present invention are described in detail according to appended drawings.
Referring to FIGS. 1-3 , a blade assembly of a blender consists of a first and a second blade ( 3 , 4 ) spaced by a gasket ( 71 ) and other three gaskets ( 72 , 73 , 74 ) are provided on the bottom of the second blade ( 4 ). Said first and second blades ( 3 , 4 ) have a square axial hole ( 38 , 47 ) provided on each thereof, and a screw ( 6 ) which can pass said axial holes ( 38 , 47 ), gaskets ( 72 , 73 , 74 ) and screwed into a receiving hole ( 11 ) of a drive shaft ( 1 ) for fastening the blades ( 3 , 4 ). A seat ( 2 ) which corresponds with said drive shaft ( 1 ) is provided under, and a gear ( 5 ) is provided on the bottom of the seat ( 2 ). To ensure both blades can be fixed tightly, two gaskets ( 75 , 76 ) are provided further between the screw ( 6 ) and the first blade ( 3 ).
Said first blade ( 3 ) comprises a cutting edge ( 31 ) on a side and a spine ( 32 ) on another side. Referring to FIG. 4 , said first blade ( 3 ) includes further a flat portion ( 33 ) with the axial hole ( 38 ) in the center, a wing portion ( 34 ) extended respectively from the left and right side of said flat portion ( 33 ) and a tip portion ( 35 ) extended upwardly from a distal end of each wing portion ( 34 ). Each wing portion ( 34 ) is elevated from the horizontal X-axis by an upward first angle (θ 1 ), each tip portion ( 35 ) is set perpendicular with the X-axis by a second angle (θ 2 ) and an edge ( 30 ) of said flat portion ( 33 ) where connecting to said wing portion ( 34 ) is inclined by a third angle (θ 3 ) relative to the horizontal Y-axis. Said wing portion ( 34 ) is also elevated from the Y-axis by a forth angle (θ 4 ) and said vertical tip portion ( 35 ) is inclined backwardly by a fifth angle (θ 5 ).
When the first blade ( 3 ) rotates, said elevated wing portion ( 34 ) generates a turbulent flow on the upper side and a down force on the bottom, leading the content that crushed by the first blade ( 3 ) can pass downwardly and be processed by the second blade ( 4 ), increasing the efficiency and shortening the processing time. The vertical cutting tip ( 35 ) can bring the content precipitated in the bottom of the container toward the upper portion and also stabilize the blade.
Said first angle (θ 1 ) is set in a range of 15° to 25° degrees, said second angle (θ 2 ) is set to have 90° degrees, said third degree ( 83 ) is set in a range of 40° to 50° degrees, said forth angle (θ 4 ) is set in a range of 5° to 15° degrees, said fifth angle (θ 5 ) is set in a range of 25° to 35° degrees, said sixth angle (θ 6 ) is set in a range of 10° to 20° degrees and said seventh angle (θ 7 ) is set in a range of 15° to 25° degrees.
Said cutting edge ( 31 ) and tip portion ( 35 ) of the first blade ( 3 ) are provided with a plurality of waving shapes ( 36 ), and each waving shape ( 36 ) comprising pluralities of teeth ( 37 ).
Said second blade ( 4 ), as shown in FIG. 5 , comprises a cutting edge ( 41 ) on a side and a spine ( 42 ) on another side. Said second blade ( 4 ) further includes a flat portion ( 43 ) having said axial hole ( 47 ) in the center and a wing portion ( 44 ) extended respectively from a left and right side of said flat portion ( 43 ). Each wing portion ( 44 ) is set downwardly from the horizontal X-axis by a sixth angle (θ 6 ) and an edge ( 40 ) of said flat portion ( 43 ) where connecting to said wing portion ( 44 ) is inclined from the horizontal Y axis by a seventh angle (θ 7 ).
Said sixth angle (θ 6 ) is set in a range of 10° to 20° degrees and said seventh angle (θ 7 ) is set in a range of 15° to 25° degrees.
Another embodiment of said second blade ( 4 ) is disclosed according to FIG. 6 , wherein said wing portion ( 44 ) of the second blade ( 4 ) includes an upper and a lower portion ( 441 , 442 ). The upper portion ( 441 ) is extended respectively from a left and right side of said flat portion ( 43 ) and each upper portion ( 441 ) is set downwardly from the horizontal X-axis by a sixth angle (θ 6 ) and an edge ( 40 ) of said flat portion ( 43 ) where connecting to said upper portion ( 441 ) of the wing portion ( 44 ) is inclined by a seventh angle (θ 7 ).
Said sixth angle (θ 6 ) is set in a range of 40° to 50° degrees and said seventh angle (θ 7 ) is set in a range of 15° to 25° degrees.
Said cutting edge ( 41 ) and tip portion ( 45 ) of the second blade ( 4 ) are provided with a plurality of waving shapes ( 46 ), and each waving shape ( 46 ) comprising pluralities of teeth ( 47 )
The bending second blade ( 4 ) creates a turbulent flow, allowing the content that need to be processed cycling between both first and second blades ( 3 , 4 ), blending into finer particles. The waving-designed cutting edges ( 31 , 41 ) of the first and second blades ( 3 , 4 ) can cut the fiber of the food or fruit finely with efficiency.
The structure of said seat ( 2 ) is shown in FIG. 3 . Said seat ( 2 ) consists of a conical portion ( 21 ) provided on a top end thereof, a threaded connecting portion ( 23 ) provided on a bottom end and a flange ( 22 ) provided in between for holding an O-ring ( 29 ). Said seat ( 2 ) incorporates two ring seals ( 24 , 25 ) to avoid of the liquid penetrating therein, two bearings ( 27 , 28 ) and a bearing cap ( 26 ) sheathing thereon.
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A blade assembly of a blender consists of a first and a second blade. The first blade has an elongated and slightly elevated body with two vertical tips, and the second blade with the body bent downwardly. The unique design of said first and second blades can create a turbulent flow, allowing the content in the container cycling between the blades to achieve finer particle and efficient processing time.
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BACKGROUND OF THE INVENTION
The field of the present invention relates to handheld scanners such as for example a laser scanner used to read bar code labels.
SUMMARY OF THE INVENTION
A handheld laser scanner, used for the purpose of non-contact reading of bar codes, emits a scanning line of laser light from an opening on one end of the scanner. The scanner includes a protective housing which incorporates all electronics, optics, light sources, and scanning mechanisms necessary to generate the scanning beam of light, detect the light scattered by the bar code, convert the detected light energy into a digital bit stream, decode the digital information and turn it into a valid bar code, and communicate that information to a data terminal. The scanner includes an oval-shaped handle and a unique round dome-shaped scanner head. This scanner also includes a transparent scanning window above the trigger area of the dome, markings on top of the scanner to aid with aiming, and a multi-color indicator light on top of the dome.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a right side elevation view of a handheld scanner according to the present invention; and
FIG. 2 is a top plan view of the handheld scanner of FIG. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention discloses a new type of handheld laser scanner, with features to make it easier for the scanner manufacturer to assemble the unit as well as easier for the scanner user to actuate, aim, support in the hand, and observe scanner indicator lights during operation.
In one embodiment of the invention, the scanner housing described below will enclose the following parts: a laser light source such as a visible laser diode, a focusing means for the light source, a scanning means for the light source, a means of relaying the scanning beam away from the scanner housing so that it hits a target bar code, a means of collecting the light energy scattered by the bar code, a means of converting that light energy into an analog electronic signal representative of the bar code, a means of converting that analog electronic signal into a digital bit stream, a means of translating the digital bit stream into valid bar code information, a means of formatting the bar code data so that it may be understood properly by a data terminal, a means of communicating with a data terminal, and a means of transmitting the scanned bar code data to the data terminal.
Referring to FIG. 1, the scanner housing 1 consists of several parts. It includes a handle portion 1 which has an oval cross section in the narrow part, and opens up to form a large circular section ending at the seam 7. It also includes a top dome portion 2 and a transparent scanning window 4. This transparent scanning window 4 allows the laser scanning beam to exit from the scanner toward a bar code, as well as to collect the scattered light from the bar code and convert it into valid bar code information.
Mounted on the scanner housing and more or less directly under the scanning window 4 is a trigger 3, which is finger-activated. When pushed, it activates all electronics inside the scanner, so that the laser turns on, the scanning mechanism is set in motion, and all analog detection and digital processing electronics are activated. By pushing the trigger, the scanner can now be used to read labels.
Referring to FIG. 2 the top of the scanner dome 2 includes several other features of importance to this invention. First of all, two aiming lines 5 are painted, molded, or marked in some other way on the top of the dome in a "V" shape as shown on the drawing. These lines touch the edge of the dome at the edges of the transparent scanning window 4. The aiming lines 5 meet at a point which lies on a line running between the center of the scanning window and the center of the dome. Because these lines form a wedge shape which is easily visible to the scanner operator, these aiming lines make it easier for the scanner operator to aim the scanner at the bar code.
The top of the dome 2 also includes a multi-color LED indicator 6 at the rear end of the scanner, and along the same line between the center of the dome and the center of the transparent scanner window 4. This LED indicator 6 can, in one embodiment, glow amber when the trigger is depressed and the laser beam is activated, and then turn green momentarily when a bar code has been read successfully. The LED indicator performs the multiple functions of providing visual feedback to the user as to the status of laser scanning and label decoding.
The LED indicator 6 also provides additional aiming cues for the user in that its linear shape makes it an additional pointer to guide the user to aim the scanner along a line drawn between the LED indicator and the center of the transparent scanning window 4.
The seam 7 between the handle I and the top of the dome 2 also provides aiming cues as well, since it is lined up with the center of the outgoing scanning beam.
In one embodiment, the scanner would be assembled with data terminal interface electronics in the handle 1, and all other electronics plus the optomechanical scanning subsystem in the dome portion of the scanner.
One feature of the present invention, as shown in FIG. 1, is the comfortable round shape of the dome portion of the scanner, which allows the scanner to rest comfortably on the hand eve without scanning. This minimizes the fatigue associated with more conventional scanner products.
A second feature of the present invention, as shown in FIG. 2, is the use of the aiming lines 5 as a means of guiding the user to aim the scanner more intuitively in the same direction as the output scanning beam.
A third feature of the present invention, as also shown in FIG. 2, is the positioning of the LED indicator light 6 toward the back of the scanner and on the top of the dome, so that it is easy for the user to see during normal operation.
A fourth feature of the present invention, as also shown in FIG. 2, is the positioning of the LED indicator light 6 in such a way that it can be used as an additional scanner aiming cue by the user.
A fifth feature of the present invention, as also shown in FIG. 1, is the use of the seam 7 between the top of the scanner dome 2 and the handle 1 as an additional scanner aiming cue for the user.
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A scanner including an oval-shaped handle and a round dome-shaped scanner head with a transparent scanning window above the trigger area of the dome. Markings on top of the scanner to aid with aiming, and a multi-color indicator light on top of the dome.
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BACKGROUND OF THE INVENTION
The present invention relates to protective linings in general, and more particularly to a protective lining arrangement for use in industrial halls, especially in large-area storage halls, and which can be mounted on pre-formed foundations or floors, especially on those consisting of concrete.
The pollution of underground water and the resultant endangerment of the potable water by chemical substances, especially by chlorinated hydrocarbons, has been publicized to a large extent over the several past years. The storage of such chemical substances requires especially cautious preventative and monitoring measures, inasmuch as damaging events may occur, as established by experience, as a result of leakage or accidents. To deal with this problem, it has already been proposed to give the floor regions of the storage facilities tub-shaped constructions and configurations, and to use steel structures or concrete with suitable surface coatings for this purpose. Even the filling stations for such environmentally noxious liquid substances must be taken into consideration in this respect, and the aforementioned tub-shaped structures must be used therein. The same considerations are also applicable for the containers for such products.
However, experience has shown that collecting tubs of this kind do not assure sufficient safety against leakage particularly of solvents on the basis of chlorinated hydrocarbons, inasmuch as even small unrecognized leaks result in a permanent environmental damage and inasmuch as concrete is not completely impermeable to such products.
SUMMARY OF THE INVENTION
Accordingly, it is a general object of the present invention to avoid the disadvantages of the prior art.
More particularly, it is an object of the present invention to provide a protective lining arrangement which does not possess the drawbacks of the known arrangements of this type.
Still another object of the present invention is to devise a protective lining arrangement of the type here under consideration which is stable enough to be withstand considerable loading by vehicles, machines or stored goods, and yet is highly resistant to the development of leakage cracks or the like.
It is yet another object of the present invention to design the above arrangement in such a manner as to provide for an early detection and localization of any leakages that may occur despite all precautions, in any event well before the occurrence of any seepage into the ground.
A concomitant object of the present invention is so to construct the arrangement of the above type as to be relatively simple in construction, inexpensive to manufacture, easy to use, and yet reliable in operation.
In keeping with these objects and others which will become apparent hereafter, one feature of the present invention resides in a protective lining arrangement, particularly for industrial halls and especially for large-area storage halls, for mounting on a pre-formed foundation, especially of concrete. This arrangement includes at least one protective lining component including at least one lower plate which is connectable to the foundation, at least one upper plate, and at least one shape-stable distancing layer interposed between the upper and lower plates and separating them from one another while simultaneously forming an air-tightly closable gap space between the upper and lower plates; leakage monitoring means; and means for connecting the leakage monitoring means with the gap space.
The protective lining component, which is constructed in accordance with the present invention so as to be double-walled, is thus provided with a gap space that is filled with a shape-stable and yet air-permeable distancing material and that is gas-tightly closable and connectable to the leakage monitoring device. The upper and the lower plate of the protective lining component may be made of a slightly or highly alloyed steel or of chemically resistant alloys and compounds, such as tombac or, if the loading is correspondingly small, even of welded-together synthetic plastic material webs. The shape-stable material, which is to be loadable in compression and yet still has to be air or gas permeable, can be constituted above all by a metallic mesh, especially by expanded metal mesh. The expanded metal mesh is a punched sheet metal material where apertures are punched as well as metal bending operations are performed in the original sheet metal material in the course of the punching operation. In this manner, there is obtained a mesh-like, three-dimensional structure with a high loadability in compression.
The securing of the protective lining plates is accomplished, in an advantageous manner, by means of holding strips of steel which are connected to the foundation either by dowels or by means of anchors embedded in the concrete foundation already during the formation of the latter. The lower plate of the protective lining component is connected to the holding strip either by point welds or by continuous welded joints. When two adjacent ones of the lower plates are welded in abutment with one another, then they can also be simultaneously welded to the holding strip. Another possibility is that one of the lower plates is welded to the holding strip first, and subsequently the other lower plate is also welded in an overlapping relationship. Advantageously, the lower plates are welded to the holding strip in accordance with a predetermined welding plan in a so-called pilgrim welding process; during the performance of this welding process, short strips are being welded at a distance from one another and in alternation with each other, in order to obtain the smallest possible thermal expansions and stresses. For a further improvement of the adhesion to the foundation, additional holding strips may be provided underneath the lower plate, and these additional holding strips may be welded to the lower plate by welded joints that are provided in bores that are formed in the lower plate.
If it is expected that vapor diffusion will exist from the area of the foundation, then advantageously a vapor barrier layer, for instance in the form of a tarred damping board, is positioned between the foundation and the lower plate.
For the further building-up of the protective lining component, the expanded metal layer is loosely positioned on top of the thus secured lower plate. Subsequently thereto, the upper is positioned on top of the expanded metal layer and is sealingly welded to the lower plate, preferably again in the aforementioned pilgrim welding operation. When the floor or foundation area is large, two or more of the protective lining components are being used. The gap spaces of these components are advantageously separated from one another in a vacuum-tight manner, and they are connectable with one another by respective conduits, for the purpose of leakage detection and leakage search. For these connections, there are advantageously being used U-shaped tubular sections which are connectible to mutually adjacent ones of connecting nipples of each two adjacent ones of the protective lining components.
A slight inclination is advantageously provided in the protective lining during its formation. This slight inclination may lead to and terminate at a drain or sump, from which any liquids which may be present on the top of the protective lining can be more easily exhausted or pumped out. The sump may also be lined by a double-walled jacket or lining of the type discussed above.
In the bottom region, there may be further provided depressions, such as pits, for instance working pits as used in industrial plants, or channels, for instance for the reception of rails. These depressions are also lined with a double-walled protective lining of the above-discussed construction. The pits or channels constitute collection or accumulation regions for possibly escaping chemical substances or liquids, and they are so dimensioned that the contents of, for instance, a drum or another container, or a kettle of a kettle carriage that is to be unloaded there, can be received therein.
For the connection of machines and devices to the protective lining arrangement, bolts or nuts may be welded to the upper plate of the respective component. For the securing of more massive machines and devices, mounting plates are welded to the upper plate, and these mounting plates may then carry, in turn, the mounting nuts or bolts. What is important is that the double-walled protective lining is not drilled through during the mounting of such machines or devices.
The double-walled protective lining may be prefabricated one component after another. In this connection, it is particularly advantageous when the thus prefabricated components are open on one side, and these unilaterally open components are then welded shut by means of a covering strip or an overlapping plate. Correspondingly, the individual pit or channel regions can be prefabricated and only later assembled with one another and with other components.
For the accomplishment of a leakage-proof connection to a wall, the respective protective lining component may be bent upwardly through 90° at its marginal region that is adjacent to the wall in question, and this upwardly bent region can be connected to the associated wall by suitable angled connectors or brackets.
In accordance with a further advantageous aspect of the present invention, the gap spaces of the protective lining can be evacuated through a suction connection, and they are connected to a manometer that is incorporated in the leakage monitoring device. In this arrangement, it is particularly advantageous when the suction conduit is connected at the lowest region of the gap space, and when the measuring conduit is connected at the highest region of the gap space. A liquid lock may be incorporated in the suction conduit. This liquid lock serves for preventing any liquid which may be drawn into the suction conduit from reaching the leakage monitoring device. In addition thereto, detonation prevention devices may be provided in the suction conduit and/or in the measuring conduit. These devices or barriers prevent flame or conflagration propagation from one of the regions to another.
A closable filling and/or testing nipple may be provided at a region of the gap space which is remote from the measuring conduit connection and may be used for admitting testing gas into and/or for the testing of the entire protective lining arrangement. This nipple may be used for supplying, for instance, an inert gas, such as nitrogen, into the gap space for leakage detection or for filling such gap space, prior to its evacuation, with such inert gas for corrosion reduction.
When a leakage occurs, then the gap spaces of the individual protective lining components can be separately connected, for the purpose of leakage location search, to the leakage monitoring device, and they may be thus tested for integrity and absence of leaks. The same result can be achieved in that the gap spaces of the respective protective lining components are disconnected one after the other from the assembly of such gap spaces, and the thus obtained partial gap space assemblies are connected to the leakage monitoring device and tested for their absence of leaks. In this manner, the location of any leak, or the region of occurrence of such a leak, can be found relatively quickly even in huge industrial halls.
BRIEF DESCRIPTION OF THE DRAWING
The present invention will be described below in more detail with reference to the accompanying drawing in which:
FIG. 1 is a sectional view of a fragment of a protective lining component of the present invention, taken in a vertical plane;
FIG. 2 is a view similar to FIG. 1 but taken at an abutment region of two adjacent protective lining components;
FIG. 3 is a perspective view from above of a protective floor lining constituted by a plurality of adjacent protective lining components of FIGS. 1 and 2; and
FIG. 4 is a partially sectioned view of a floor region of an industrial hall with the protective lining arrangement of the present invention installed therein.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the drawing in detail, and first to FIG. 1 thereof, it may be seen that the reference numeral 11 has been used therein to identify one of many components of a floor covering or of a similar protective lining. The component 11 consists essentially of an upper plate 1 and a lower plate 2, as well as of a distancing layer 3 which is interposed between the upper plate 1 and the lower plate 2. The upper plate 1 and the lower plate 2 are advantageously made of a relatively thick metal sheet, preferably of steel, while the distancing layer 3 is constituted by or made of expanded metal. The expanded metal of the distancing layer 3 has a mesh-like, three-dimensional structure exhibiting a high transverse loadability.
Webs can be arranged in a plurality of layers that are welded to one another.
Because of the presence of apertures and bent metal portions in the expanded metal of the distancing layer 3, the layer 3 is permeable to air and other gaseous media, as well as to liquids, so that a continuous gap space 8 is present between the upper plate 1 and the lower plate 2. This gap space 8 may be either evacuated or filled with a gaseous medium. The lower plate 2 of the protective lining can and will be connected in use by welding to holding strips 4 which are advantageously also made of steel and which, in turn, are connected by respective screws 6 and 7 to a pre-formed concrete foundation. The evacuatable gap space 8 is connected by means of a measurement conduit 16 to a leakage detection arrangement 17.
At least one holding strip (4) situated underneath a portion of said lower plate (2) and connected to said foundation (5). Said lower plate (2) has at least one opening therein which is bounded by a rim at which said lower plate (2) can be welded to said holding strip (4).
It may be seen particularly in FIG. 2 of the drawing that two adjacent ones of the components 11 of the protective lining are connected with another at their regions at which they abut one another and are also secured to the foundation 5. The connecting screws 6 and 7 penetrate through the holding strip 4 at regions that are transversely offset from the center of the holding strip 4, either in an offset relationship, or in a parallel relationship, with respect to one another. As a result of this transversely offset arrangement of the screws 6 and 7, there is obtained an integral central region of the holding strip 4 which is not damaged by the presence of any screw-receiving holes that could eventually constitute leakage locations. The lower plates 2 of the two adjacent protective lining components 11 are welded to one another in abutment with each other and are also weldedly connected, by the same welding seam, to the holding strip 4. The expanded metal distancing layers 3 are then placed from above onto the adjacent lower plates 2 that are connected in this manner to the concrete foundation or floor 5.
Subsequently thereto, the upper plate 1 that is situated at left in FIG. 2 of the drawing is placed from above onto the associated distancing layer 2 and is sealingly welded at its edge region by means of a continuous welding seam 14 to the associated lower plate 2 that is situated thereunder. Simultaneously therewith, even the respective expanded metal distancing layer 3 is welded to the associated plates 1 and 2. After this operation is completed, the upper plate 1 which is illustrated at the right in FIG. 2 of the drawing is positioned from above onto the thus obtained assembly, in such a manner that its marginal or edge portion overlaps the left-hand upper plate 1. Thereafter, the right-hand and the left-hand upper plates 1 are weldingly connected to one another by means of a continuous sealing welding joint 10.
In this manner, there are obtained two of the gap spaces 8, the width (vertical dimension) of which is determined by the wall thickness of the expanded metal distancing layers 3. When corresponding sealing welded joints are provided at the remaining three sides of each of the protective lining components 11, these two gap spaces 8 can be separately evacuated. The two gap spaces 8 are separated from one another as far as their evacuation is concerned, but they can be connected with one another for the purpose of leakage detection and leakage search. U-shaped tubular sections 12 are being used for connecting such neighboring gap spaces 8 with one another. The tubular sections 12 are connected to mutually adjacent connecting nipples of two adjacent ones of the protective lining components 11. A floor protection lining assembly which is illustrated in FIG. 3 of the drawing includes five of the protective lining components 11 which are welded to one another at their regions at which they abut one another, and the gap spaces 8 of which are connected in series by means of the respective tubular sections 12.
An example of the structure of the protective lining arrangement of the present invention is illustrated in FIG. 4 of the drawing. In this implementation of the present invention, there is provided a plurality of the protective lining elements 11 which are connected with one another at respective abutment regions 20 at which they abut one another. The protective lining components 11 are constructed in the above-discussed manner so as to be double-walled, and each of them includes, situated between and embraced by the upper plate 1 and the lower plate 2, the aforementioned distancing layer 3 made of expanded metal, and the gap space 8. The gap spaces 8 are connected with one another at the respective connecting nipples by respective U-shaped tubular sections or members 12.
One of the protective lining components 11 is provided with a depression 23 which constitutes a pump drain. Respective lateral lining portions 24 and bottom lining portion 25 which together bound the depression 23 are also double-walled and have the evacuatable gap space 8. At the regions of respective side walls 27 of the factory or storage hall or bay, the marginal portions of the respective protective lining components 11 are bent upwardly through 90° and, in this manner, they form a tub rim wall 26 which has a height, for instance, of 10 to 40 centimeters. A runoff sheet metal member 29, which is secured to the respective side wall 27, overlaps and embraces an upper edge region 28 of the rim wall 26, so that any liquid which may flow downwardly on the side wall 27 does not penetrated into an interspace 30 present between the protective lining and the side wall 27; rather, such liquid will flow on the runoff sheet metal member 25 onto the supervised or monitored floor protection lining. A tar-coated damping board 40 prevents vapor diffusion from the foundation 5 into the protective lining.
At least one additional protective lining component similar to the protective lining component and having an additional gap space (8). The additional gap space (8) is gas-tightly separated from said gap space (8). Said connecting means includes a separate measuring conduit (16) for each of said gap spaces (8). A separate suction conduit (31) is furnished for each of said gap spaces (8) as well as means for establishing communication between said measuring conduit (16) and suction conduit (31) and said leakage monitoring means (32).
The gap space 8 of the protective lining is connected, by means of a suction conduit 31 and the aforementioned measuring conduit 16, with the leakage detection arrangement 17 which includes a subatmospheric pressure measuring device 32. A suction conduit connection 33 for the suction conduit 31 is disposed at the vicinity of the lowest or deepest point of the protective lining, whereas the measuring conduit 16 is connected to the gap space 8 at a highest point region 34 of the gap space 8. A liquid lock 35 is interposed in the suction conduit 31. The liquid lock 31 serves for the prevention of drawing-in liquid in the event of occurrence of a leakage. Furthermore, detonation safety devices 36 are provided both in the suction conduit 31 and in the measuring conduit 16. These detonation safety devices 36 serve in the event of fire for the prevention of penetration of flames or conflagration from one region to the other. A filling and testing nipple 37 is arranged at a side of the upwardly bent tub rim 26 of the protective lining that is opposite to the measuring conduit line connection 34. The filling and testing nipple 37 can be closed by means of a ball tap 38, and it may be supplied, for leakage control or testing of the entire protective lining, with an inert gas which consists, for instance, or nitrogen.
For securing of machines or devices on the protective lining components 11, bolts 41 or nuts can be welded to the respective upper plates 1. For larger devices and machines, mounting plates 42 are welded to the upper plate or plates 1, and these mounting plates 42 then, in turn, carry mounting bolts 43 or nuts.
The upper plate 1 may be constructed or configured as a sandwich plate which is provided with a covering 44 of a synthetic plastic material. This synthetic plastic material covering 44 may be applied to the upper plate or plates 1 by being painted on, welded to, glued to, or poured onto the upper plate or plates 1. It is also possible for the covering 44 to be constituted by an industrial flooring, a synthetic resin coating, or a paint layer, or for such flooring, coating or layer to be applied over the upper surface of the covering 44. The industrial flooring may be made, for instance, on a cement or synthetic resin/cement basis. The coating is to be particularly chemically inactive and is to prevent the formation of sparks, as they would develop, for example, if forklift trucks were driven on metallic flooring and if their prongs were allowed to come into contact with and rub against such metallic flooring, or if handling steel sheet bundles or containers and allowing them to slide along a metallic flooring with attendant friction. The protective lining as described above is particularly intended for use in industrial or storage halls or bays, in which explosion protection is to be assured as well.
While the present invention has been described and illustrated herein as embodied in a specific construction of a floor lining for industrial uses, it is not limited to the details of this particular construction, since various modifications and structural changes are possible and contemplated by the present invention. Thus, the scope of the present invention will be determined exclusively by the appended claims.
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A protective lining arrangement, which is intended for use in industrial halls, especially in large-area storage halls, and, on the one hand, is to be capable of being loaded to a high degree by vehicles, machines and stored goods while, on the other hand, is to provide excellent protection against undesirable seepage of hazardous liquid substances into the ground, consists of a plurality of protective lining components which are connected to one another by welded joints. Each of such protective lining components includes an upper plate, a lower plate, and a distancing layer of expanded metal which is interposed between the upper and lower plates and keeps them apart by a predetermined distance, while simultaneously providing between the two plates a gap space having a width corresponding to the predetermined distance. The gap spaces of the protective lining components can be evacuated and are connected via a measuring conduit to a leakage monitoring device.
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FIELD OF THE INVENTION
This invention relates to communication systems, and more particularly to a system and method for removing the Doppler shift in the frequency of a signal transmitted from a mobile platform, and/or removing the Doppler shift from a signal received by a mobile receiving platform.
BACKGROUND OF THE INVENTION
In a mobile communication network, Doppler shift occurs when the velocity vector of a transmitting mobile platform differs from the velocity of a receiving mobile platform. For example, when two platforms are stationary with respect to each other (or with respect to a common reference frame) and are communicating with each other, the frequency of the signal received by the receiving platform from the transmitting platform will be the same as the frequency transmitted by the transmitting platform. In this case no Doppler frequency shift exists since the distance between the two platforms remain constant. When the distance between the two platforms is reducing with time, the frequency of the signal received by the receiving platform from the transmitting platform will be higher than the frequency transmitted by the transmitting platform due to the Doppler affect. When the distance between the two platforms is increasing with time, the frequency of the signal received by the receiving platform from the transmitting platform will be lower than the frequency transmitted by the transmitting platform due to the Doppler affect.
It is noted that distance between two platforms can also increase or decrease with time though one of the two platforms is stationary with respect to a common reference frame. This relative distance variation between the two platforms with respect to time will result in a Doppler frequency shift that needs to be accounted for by the receiving platform regardless whether it is the moving platform or the stationary platform with respect to a common reference frame.
For a nominal frequency of f 0 , the actual frequency at the receiver is f 0 +Δf, where Δf is the Doppler shift. To accommodate this variation in the received frequency of an electromagnetic wave signal, previously developed systems call for the receiver electronics to accept a wider frequency bandwidth than the nominal frequency bandwidth of the signal. This increases the amount of noise entering the receiver, thereby reducing the signal-to-noise ratio. In addition, the variation in frequency means that the system must use larger guard bands, i.e., unused bands of frequency between each link's nominal frequency and the frequencies of other links. This arrangement wastes bandwidth. Furthermore, because the incoming frequency is not precisely known, the receiving modem must scan over a range of frequencies before it can lock onto the carrier. This reduces the time available for data to be received, especially in time division multiple access (TDMA) systems where the modem must resynchronize at the beginning of every time slot. The above described Doppler shift applies to acoustic signals having a frequency of possibly less than 1 Hz to hundreds of KHz, as well as to electromagnetic wave signals. The Doppler shift has the negative effect of increasing the time to establish a two-way communication link due to longer modem synchronization times, the drawback of necessitating the extra bandwidth needed for guard bands, and serves to increase noise present with the received signal as a result of the use of the guard bands.
SUMMARY OF THE INVENTION
The present invention is directed to a system and method for compensating for the Doppler shift effect on a signal being transmitted from a transmitting platform to a receiving platform, where at least one of the two platforms is a mobile platform.
In one preferred implementation the system of the present invention involves the use of a transmitter having an associated processor. The transmitter is located on a mobile platform. A receiver having its own processor is disposed on a separate platform. Signals, for example electromagnetic wave signals, are transmitted from the transmitting mobile platform to the receiving mobile platform. The transmitting mobile platform determines its velocity vector relative to a reference frame that is common to all platforms in the system, as well as a unit vector that represents the direction of the receiving platform relative to the transmitting platform. The processor associated with the transmitter uses the velocity vector and the unit vector to calculate a Doppler shift that would be experienced by the receiving platform if the receiving platform were stationary with respect to a common reference. The processor then alters the transmitted frequency of the signal from the transmitter as necessary to cancel the Doppler shift that the receiving platform would experience.
In another preferred implementation, the receiving platform operates to cancel the Doppler shift on a signal that it is receiving from a transmitting platform. In this embodiment the receiver determines a vector of velocity relative to the common reference frame, as well as a unit vector in the direction from itself to the transmitting platform. A processor associated with the receiver uses this information to determine a Doppler shift that would be experienced by the receiving platform when receiving the signal from the transmitting platform, if the transmitting platform was stationary. The process to adjust the frequency of the receiver is needed to cancel the Doppler shift in the receive signal that is attributable to movement of the receiving platform. In another alternative preferred embodiment, both the receiving and transmitting platforms perform the above-mentioned Doppler shift determinations. The transmitting platform removes the Doppler shift that would be imparted to the transmitted signal as a result of motion of the transmitting platform, while the receiving platform similarly determines and removes the Doppler shift component that is attributable to its own motion, relative to the transmitting platform.
Another alternative preferred embodiment is designed for two-way communications where each platform includes both a receiver and a transmitter that perform the above-mentioned Doppler shift determinations. The transmitter on each platform removes the Doppler shift that would be imparted to the transmitted signal (and experienced by the other mobile platform), as a result of its own motion, while the receiver on each platform similarly determines and removes the Doppler shift component that is attributable to its own motion, relative to the other platform.
The present invention is not limited to electromagnetic wave signals but can be applied to acoustic signals, including sonar signals, as well as optical signals including laser signals. Furthermore, the present invention can be used with electromagnetic wave or light signals transmitted through the atmosphere or between spacecrafts, or to electromagnetic wave or acoustic signals between two underwater vessels communicating with each other while submerged underwater. The present invention is equally applicable to situations where one platform is stationary and the other one is mobile, or where both platforms are mobile.
The features, functions, and advantages can be achieved independently in various embodiments of the present inventions or may be combined in yet other embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:
FIG. 1 is a simplified schematic diagram of two mobile platforms communicating with each other and further illustrating, in simplified fashion, the unit vectors that each makes use of in determining a direction from it to the other platform;
FIG. 2 is a simplified block diagram of the components on the transmitting platform and the receiving platform;
FIG. 3A is a flow chart illustrating the steps performed by a transmitting mobile platform, in accordance with a preferred implementation of the present invention; and
FIG. 3B is a flow chart illustrating the steps performed by a receiving mobile platform, in accordance with a preferred implementation of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.
Referring to FIG. 1 , there is shown a system 10 that includes a preferred implementation of the present invention. The system 10 generally includes a transmitting mobile platform 12 having a transmitter 14 carried thereon, and a receiving mobile platform 16 having receiver 18 located thereon. Assuming for the moment that receiving platform 16 is stationary or moving toward mobile platform 12 , then electromagnetic wave signals transmitted from transmitter 14 of transmitting platform 12 , as represented by signal line 20 , would be increasing slightly in frequency since platform 12 is moving towards platform 16 . This increase in frequency represents the Doppler shift that the receiving platform 16 “sees.” If receiving platform 16 is moving towards transmitting platform 12 , then an additional Doppler shift component will be experienced by receiving platform 16 due to its own movement.
With brief reference to FIG. 2 , the transmitter 14 on the transmitting platform 12 is in communication with a processor 22 . An antenna 24 is used for transmitting electromagnetic wave signals. The receiving platform 16 similarly includes a processor 26 which is in communication with the receiver 18 . An antenna 28 is used for receiving electromagnetic wave signals from the receiver 18 . Antennas 28 and 24 may be located on an exterior surface of each mobile platform 12 and 16 or at a suitable location internal to a fuselage of each mobile platform 12 and 16 . Furthermore, while the transmitting platform 12 and the receiving platform 16 are each illustrated as aircraft, it will be appreciated that the present invention can be implemented with any mobile platform such as trains, busses, ships, satellites, spacecrafts, missiles, submarines, torpedoes, other airborne vehicles, other undersea vessels, other land vehicles, or other space vehicles. Furthermore, each mobile platform could have a bi-directional transceiver for both transmitting and receiving electromagnetic wave signals. In this instance, as will be explained in greater detail in the following paragraphs, each mobile platform will determine the necessary Doppler shift corrections needing to be applied, on both transmit and receive operations, as a result of its own motion.
Referring further to FIG. 1 , the transmitting platform 14 , to remove the Doppler effect that will be experienced by the receiving platform 16 due to the motion of the transmitting platform 12 , must determine 1) its own velocity relative to a common, pre-established reference frame, and 2) a direction to the receiving platform 16 relative to the common reference frame. If the receiving platform 16 is a mobile platform such as illustrated in FIG. 1 , then the receiving platform also must determine its velocity relative to the same (i.e., common, pre-established) reference frame, and also its direction relative to the transmitting platform 12 relative to the same common, pre-established reference frame. The scenario with both platforms 12 and 16 moving towards each other will be assumed for the purpose of the following description.
The total Doppler shift of the electromagnetic wave signal 20 received at the receiver 18 is due to two velocities: the velocity of the transmitting platform 12 , as well as the velocity of the receiving platform 16 . Assuming for the moment that platform 16 is stationary, the received frequency at receiver 18 can be represented by the following equation:
Δ f T =f 0 r TR ·v T /c
where f T is the frequency emitted by the transmitter; “c” is the speed of light; “·” represents a vector dot product; where Δf T is the frequency shift due to the transmitting platform's motion; and where f 0 represents the carrier frequency of the transmitted signal 20 for the stationary platform.
With the present invention, each mobile platform 12 , 16 performs local adjustments to eliminate the part of the frequency shift that is due to its own motion. For example, if the transmitting platform 12 and the receiving platform 16 were each stationary, the transmitting platform 12 would transmit at f 0 and the receiving platform 16 would receive the electromagnetic wave signal 20 at f 0 . However, since the transmitting platform 12 is moving relative to the receiving platform 16 , the transmitting platform 12 first determines its velocity vector v T relative to an agreed upon common reference frame, for example, Local Earth Coordinates or common stellar coordinates. In this regard, it will be appreciated that a common coordinate frame of reference for position and velocity in a three dimensional coordinate system will be necessary in most instances. Three dimensional coordinate systems can be obtained by the aircraft's on-board navigation system which provides longitude, latitude, altitude, direction, and velocity with respect to Local Earth Coordinates. This can be provided by multiple earth stations or multiple GPS satellites (GPS constellation) to correlate a position and determine a velocity. This can be accomplished for a spacecraft by referencing to multiple heavenly bodies (sun, planets, stars, constellations, etc.) to triangulate a position and determine a velocity. There are numerous other common coordinate navigation systems that can be used to determine position and velocity such as Long Range Radio Aid to Navigation (LORAN), VHF Omnidirectional Range navigation system (VOR), etc.
The transmitting platform 12 must then determine a unit vector r TR in the direction from itself to the receiving platform 16 with respect to the common reference frame. The precise mechanism or system for determining the unit vector r TR depends on the system in which the invention is used. For example, and with further reference to FIG. 1 , if the satellite 30 is employed with the system 10 , then each platform 12 and 16 can continuously report its position to other platforms operating in a given region via the satellite's 30 transponder. This would be assuming that the satellite is a geosynchronous satellite whose location is constant relative to a position on Earth. Other means of establishing a common reference frame could involve having each transmitting platform continuously track the direction of its link partners using synchronous beam cloning, using a signal strength indication in combination with pointing a directional antenna, or other suitable means.
Referring further to FIG. 1 , since the transmitting platform 12 knows its approximate position relative to the satellite 30 , and since the transmitting platform is able to retrieve approximate position information on the position of the receiving platform 16 via the satellite 30 , a unit vector 32 (r TR ) can be determined. Unit vector 32 represents the direction from the transmitting platform 12 to the receiving platform 16 . Similarly, the receiving platform 16 determines a unit vector 34 that represents the direction from it to the transmitting platform 12 . The unit vector 34 (r RT ) is also determined using position information of the position of the transmitting platform 12 that is obtained via the satellite 30 . Receiving platform 16 obtains its own position information via any suitable means, such as its inertial navigation system or from satellite 30 .
The processor 22 on the transmitting platform 12 determines the Doppler frequency shift (Δf T ) that a stationary receiver in direction r TR would observe. The processor 22 adjusts the frequency at which transmitter 14 transmits, thus changing its emitted frequency from f 0 to (f 0 −Δf T ). This cancels the Doppler shift due to the transmitting platform's 12 motion so the actual Doppler shift experienced by a stationary receiver in direction r TR would be zero.
The receiving platform 16 performs similar steps. The processor 26 initially obtains a velocity of the receiving platform 16 (v R ) using the same reference frame as the transmitting platform 12 (i.e., the common reference frame). The receiving platform 16 also determines the unit vector r RT 34 representing the direction from itself to the transmitting platform 12 . The processor 26 computes the Doppler frequency shift (Δf R ) that the receiver would observe for a signal transmitted at frequency f 0 from a stationary transmitter along the unit vector 34 (i.e., r RT ). For electromagnetic wave signals, this frequency shift can be given by the equation:
Δ f r =f 0 r RT ·v r /c
where “v r ” is the velocity of the receiving platform.
The processor 26 then adjusts the frequency setting of receiver 18 , changing its nominal frequency from f 0 to f 0 +Δf R . Given that the transmitting platform 12 has removed the frequency shift component (i.e., Δf T ) due to the transmitting platform's 12 motion, the frequency (f R ) of the signal arriving at the receiving platform 16 can be given by the equation:
f
R
=
f
0
+
Δ
f
r
+
Δ
f
T
-
Δ
f
T
=
f
0
+
Δ
f
R
.
The term f R thus represents exactly the frequency at which the receiving platform's receiver 18 expects to receive the electromagnetic wave signal 20 . This substantially eliminates the problems that arise from frequency mismatch due to the Doppler shift of the signal 20 .
In practice, the remaining frequency mismatches after the above-described Doppler shift corrections are applied are typically about 1.5-2.0 orders of magnitude smaller than the Doppler mismatch remaining when using many previous developed correction systems. Many remaining frequency mismatches are largely due to measurement errors in speed and direction, and the time lag between these measurements. Additionally, errors in frequency adjustment (i.e. imprecise voltages used to adjust frequency, or imprecise voltage-to-frequency shift coefficients) also can affect the degree of frequency mismatch reduction achieved with the present invention. However, for equipment typically used on aircraft, these errors are typically on the order of one percent to a few percent that of the Doppler shifts encountered without the benefit of the present invention. Thus, the noise entering the receiver, the frequency scan time and the guard bandwidth can all be reduced significantly compared to what is needed with previous correction systems that do not achieve the significant degree of Doppler mismatch reduction that the present invention achieves.
With brief reference to FIGS. 3A and 3B , a simplified flowchart setting forth the basic steps of one preferred implementation of the present invention 10 will be described. This implementation assumes that both the transmitting platform 12 and the receiving platform 16 are moving relative to the common reference frame. At operation 50 , transmitting platform 12 obtains a velocity vector (v T ) representing its speed, relative to the common reference frame. At operation 52 , the transmitting platform 12 next obtains the unit vector (r TR ) for the direction from it to the receiving platform 16 . At operation 54 , the processor 22 determines, from the velocity vector (v T ) and the unit vector (r TR ), the Doppler shift (Δf T ) affecting the signal 20 being transmitted as a result of the motion of the transmitting platform 12 . In operation 56 , the processor 22 then controls the transmitter 14 in a manner so that the frequency of the signal 20 transmitted is adjusted as needed to cancel out the Doppler shift (Δf T ) that will be experienced by the receiving platform 16 . These operations are periodically repeated to adjust for changes in v T and r TR . The update rate can be as low as 10 ms for fast aircraft or missiles for which the transmitting platform 12 is relatively close to the receiving platform 16 (i.e., quick dynamic shifts in Doppler). The update rate can be several seconds or longer for submarines with slow maneuvers while receiving ultra low frequency signals (slow dynamic shifts in Doppler). The update rate will depend on how fast the Doppler shift changes. Doppler shift dynamics depend on 1) how fast the relative velocity changes between the receiver and the transmitter and 2) the relative difference in platform velocity with respect to the signal velocity.
At operation 58 , the receiving platform 16 obtains velocity vector (v r ) information relative to the common reference frame. At operation 60 , the receiving platform 60 obtains unit vector (r RT ) for the direction from it to the transmitting platform 12 . At operation 62 , the receiving platform 16 determines the Doppler shift (Δf T ) affecting signal 20 as a result of its own motion, and assuming that transmitting platform 12 is stationary. Finally, at step 64 , the processor 26 adjusts the receive frequency of receiver 18 to cancel out the Doppler shift that is attributable to the motion of the receiving platform 16 . These operations are periodically repeated to adjust for changes in v R and r RT .
For a two-way communications link between platform 12 and platform 16 , there would be a receiver and a transmitter on each platform. The receiver and transmitter on platform 12 will have a common platform velocity vector (v T12 =v R12 ) and a common direction vector (r T12R16 =r R12T16 ). The resulting transmitter and receiver Doppler frequency adjustments made on platform 12 will be equal and opposite (Δf T12 =−Δf R12 ). Platform 16 would also have a receiver and a transmitter that will have a common platform velocity vector (v T16 =v R16 ) and a common direction vector (r T16R12 =r R16T12 ). The resulting transmitter and receiver Doppler frequency adjustments made on platform 16 will be equal and opposite (Δf T16 =−Δf R16 ). Thus, each mobile platform would be performing a Doppler shift correction during both transmitting and receiving operations.
The formula for Doppler shift of sound waves varies depending on whether the source is moving, the observer is moving, or both. If the observer (receiver) is moving, the formula for frequency f′ that the receiver hears is:
f ′=( v+v observer )/ v Formula 1
where v is the speed of sound in the medium, v observer is the speed of the observer (receiver) toward the source, and f is the frequency in the absence of any Doppler shift. Note that v observer is negative if the observer (receiver) is moving away from the source. If the source (transmitter) is moving, the formula for frequency f′ that a stationary receiver hears is:
f′=fv /( v−v stationary receiver ) Formula 2
where v and f are the same as before and v stationary receiver is the speed of the transmitter toward the receiver.
The two formulae combine when both transmitter and receiver are in motion:
f′=f ( v+v observer )/( v−v stationary receiver ).
For the present system and method, the receiver would use the Formula 1 above to correct the incoming frequency and the transmitter would use the Formula 2 to correct the outgoing frequency.
The present invention thus offers a means to reduce the waste of transmitter to receiver frequency synchronization time and bandwidth that is currently caused by Doppler shift in mobile communication systems. This waste is most significant in systems that use fast moving nodes like aircraft, missiles and spacecraft. The Doppler shift has less impact on slow moving systems such as automobiles, vans, trucks or land vehicles, and watercraft. With such slow moving vehicles, the signal velocity is very high compared to the speed of the vehicle as is typically the case when electromagnetic radio frequencies or light frequencies are used. Doppler shift can be significant for relatively slow moving nodes if the signal velocity is comparatively slow, as can be the case when acoustic signals are used.
While various preferred embodiments have been described, those skilled in the art will recognize modifications or variations which might be made without departing from the inventive concept. The examples illustrate the invention and are not intended to limit it. Therefore, the description and claims should be interpreted liberally with only such limitation as is necessary in view of the pertinent prior art.
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A system and method for correcting for Doppler shift in transmitted and received electromagnetic wave, light wave, or acoustic wave signals between two platforms, where at least one of the platforms is moving relative to the other. The system involves determining a Doppler shift that affects the frequency of a signal being transmitted from a transmitting platform, as a result of motion of the transmitting platform, and adjusting the frequency of the transmitted signal to cancel out the determined degree of Doppler shift that will be experienced by the receiving platform. If the receiving platform is also moving, then a determination is made as to the Doppler shift that will be imparted to the signal being received because of motion of the receiving platform. A receiver on the receiving platform is controlled to account for this degree of Doppler shift. Therefore, the Doppler shift components attributable to the motion of each, or both, platforms is accounted for.
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CROSS REFERENCE TO RELATED APPLICATION
[0001] This application claims priority based on European patent application EP 09 167 924.1, filed Aug. 14, 2009.
FIELD OF THE INVENTION
[0002] The invention relates to a drive and guide device for a needle bar in a needle loom.
BACKGROUND OF THE INVENTION
[0003] The needle bar of a needle loom must be guided during its movement in the machine stand in a direction perpendicular or essentially perpendicular to the needle-punching support surface. The guide devices provided for this purpose, whether these be rails or rods, lead to problems with heat, lubrication, and sealing. Wear must be avoided as much as possible, because otherwise the punching accuracy during operation suffers. This is disadvantageous especially at high needle-punching densities.
[0004] A guide device for the needle bar in a needle loom containing at least one pair of rocker arms, which are arranged on opposite sides of the needle bar, is known from U.S. Pat. No. 4,241,479 A. One end of each of these arms is hinged to the needle bar, while a support device is present on the other end, which supports the rocker arm in question on the machine stand so that it is free to rock. For this purpose, a first bearing surface is formed on the machine stand for each rocker arm; this first bearing surface faces a second bearing surface on the end of the rocker arm. The bearing surface on the machine stand is designed in the manner of an involute gear recess, into which a tooth designed in complementary fashion on the opposite end of the associated rocker arm engages, the tooth thus being free to rock in the gear recess. In this way, the needle bar can be guided along a straight path, wherein the elements participating in its guidance perform exclusively rolling movements.
[0005] A needle loom in which the lateral guidance of the needle bar during its up and down stroke is provided by a symmetrically designed four-bar linkage, which is hinged to the needle bar or its carrier and to the machine stand, is known from DE 10 2006 008 485 A1. The dimensions of the four-bar linkage are chosen in such a way that the Ball's point which it forms and which lies on the needle bar describes a straight path within the stroke range of the needle bar.
[0006] Although the two previously described designs avoid the sliding type of guides, which are vulnerable to wear, they are relatively complicated mechanically. The two designs contain pivot bearings on the needle bar, which must be lubricated, and the latter design also has an additional number of non-stationary pivot bearings, which increases the difficulty of lubrication even more, because the lubricant must be supplied to these non-stationary pivot bearings continuously for as long as they are in operation.
SUMMARY OF THE INVENTION
[0007] It is an object of the present invention to provide a drive and guide device for a needle bar in a needle loom, which is simple technically and which makes do with a reduced number of lubrication points.
[0008] A preferred embodiment of the drive and guide device for a needle bar in a needle loom includes a machine stand and has a first crankshaft rotatably supported in the machine stand and a needle bar supported in the machine stand movable at least up and down. The drive and guide device also includes a first connecting rod supported on a first cam of the first crankshaft connected to the needle bar and a guide device for guiding the needle bar along a path extending substantially perpendicular to a needle-punching support surface. The first connecting rod and the guide device includes a leaf spring which is rigidly connected to the needle bar to transmit a drive or guide force. The first connecting rod can be rigidly connected to the needle bar and forms a rigid unit with it, whereas the guide device comprises a guiding leaf spring, which is rigidly anchored in the machine stand, and which extends on a level which is approximately the same as that of the needle bar in the needle loom.
[0009] In a another preferred embodiment, one end of a first connecting leaf spring is attached to the end of the first connecting rod facing away from the cam. This connecting spring comprises a second end, which is rigidly attached to the needle bar, and the guide device includes a second crankshaft, which is on approximately the same level as the needle bar in the machine stand and which has at least one second cam, on which a second connecting rod is supported, the end of this second rod facing away from the second cam is rigidly connected to the needle bar.
[0010] In an additional preferred embodiment, the first connecting rod is rigidly connected to the needle bar to form a single rigid unit, and the guide device comprises a second crankshaft, which is on approximately the same level as the needle bar in the machine stand and which has at least one second cam, on which a second connecting rod is supported. One end of a second connecting leaf spring is rigidly attached to the end of this second rod which faces away from the second cam, while the other end of the second connecting leaf spring is rigidly connected to the needle bar. With an arrangement such as this, a motion component in a direction parallel to the needle- punching support surface can be superimposed on the movement of the needle bar in the direction perpendicular to the base. During a punch, this parallel component follows the movement of the nonwoven web being processed on the needle loom.
[0011] In further preferred embodiments of the invention, a first connecting rod, which gives the needle bar the motion component in a direction perpendicular to the needle-punching support surface, is connected to the needle bar by a connecting leaf spring, which is rigidly connected at one end to the connecting rod, and at the other end to the needle bar. In comparison to a guiding leaf spring, which guides the needle bar during its punching movement, this connecting leaf spring is relatively short, which prevents it from buckling out to the side during the punching movement.
[0012] A connection between the connecting rod and the needle bar can also be realized for the second connecting rod, by which a motion component parallel to the needle-punching support surface is transmitted to the needle bar. Here too, the connecting leaf spring should be short enough to prevent it from buckling during operation.
[0013] The invention can also be used in needle looms which comprise two needle bars arranged parallel to each other, which are driven by first crankshafts individually assigned to them. Each needle bar can be guided individually from the side by a guiding leaf spring or by a second crankshaft with a second connecting rod and possibly a connecting leaf spring. It is also possible, however, for both needle bars to be guided by a single guiding leaf spring or by a single second crankshaft with a second connecting rod and possibly a connecting leaf spring, provided that the needle bars are coupled to each other. If the first crankshafts rotate in opposite directions, a single coupling leaf spring is sufficient to couple the needle bars together. If the first crankshafts rotate in the same direction, two coupling leaf springs arranged one above the other a certain distance apart are provided between the two needle bars, these springs being connected rigidly to the needle bars to prevent the needle bars from tipping toward each other uncontrollably.
[0014] To minimize the flexing of the connecting leaf spring and to increase its service life, the guiding leaf spring should be as long as possible. If in fact the guiding leaf spring is long, however, there is the danger that, during operation, the moving needle bar will cause it to oscillate and possibly to flutter. To avoid such undesirable action, the guiding leaf spring may be surrounded by a stiff guard which prevents the leaf spring from oscillating. A guard of this type can consist of two rails, which are parallel to each other and which rest on the narrow sides of the guiding leaf spring, the rails being connected to each other by several pairs of bars arranged a certain distance apart. The bars of each pair form a gap between them, through which the guiding leaf spring extends. The rails can be provided at their ends with buffers of plastic or rubber, because the ends of the rails can come into contact with the parts of the machine adjacent to them. The buffers dampen the noise which may develop during operation.
[0015] The needle bar of a needle loom is put in motion by at least two connecting rods. In the case of very large working widths, it is also possible for more than two connecting rods to be used. These connecting rods are set in motion by a corresponding number of cams on the associated crankshaft. The same applies to the guide devices. It should be appreciated that while the invention is explained on the basis of only a single connecting rod and one guide device, this should not be understood as a numerical limitation.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] In order that the advantages of the invention will be readily understood, a more detailed description of the invention briefly described above will be rendered by reference to specific embodiments that are illustrated in the appended drawings. Understanding that these drawings depict only typical embodiments of the invention and are not therefore to be considered to be limiting of its scope, the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings, in which:
[0017] FIG. 1 is a schematic diagram of a drive and guide device according to the invention based on the example of a needle loom with one needle bar;
[0018] FIG. 2 is a schematic diagram of a drive and guide device according to the invention based on the example of a needle loom with two needle bars;
[0019] FIG. 3 is a schematic diagram of an alternative embodiment of a drive and guide device according to the invention based on the example of a needle loom with two needle bars;
[0020] FIG. 4 is a schematic diagram of a drive and guide device according to the invention based on the example of a needle loom in which a single needle bar has a first drive, which produces the actual punching action, and a second drive, which can move the needle bar horizontally;
[0021] FIG. 5 is a schematic diagram of a drive and guide device according to the invention based on the example of a needle loom in which each of the two needle bars has its own first drive, which produces the actual punching action, and a second drive, which can move the needle bars horizontally;
[0022] FIG. 6 shows an embodiment of the invention similar to that of FIG. 3 with an elastic connection between the needle bar and the connecting rod producing the punching movement;
[0023] FIG. 7 is a schematic diagram of an alternative embodiment of the connections of a guiding leaf spring;
[0024] FIG. 8 shows an embodiment similar to FIG. 1 , including a second drive, which gives the needle bar a motion component perpendicular to the punching motion, with an elastic connection between the needle bar and the connecting rod of the second drive;
[0025] FIG. 9 shows an embodiment of the invention similar to FIG. 6 with a second drive which is connected to the needle bar;
[0026] FIG. 10 is a perspective view of a guard surrounding the leaf spring to prevent the leaf spring from fluttering; and
[0027] FIG. 11 is an enlarged view of the circled area in FIG. 10 .
DETAILED DESCRIPTION OF THE INVENTION
[0028] In the following, specific embodiments of the invention shown in the drawings are described in detail. The diagrams in the drawings are limited for the sake of clarity to the parts of a needle loom essential to the explanation of the invention.
[0029] FIG. 1 shows a portion of the needle loom including a needle bar 1 , which carries on its bottom surface a needle board 3 equipped with needles 2 . A needle-punching support surface 4 is set up opposite the needles. Needle-punching support surface 4 serves to support the web of material (not shown) to be needled. Such web of material may be a nonwoven web or the like which, during the operation of the needle loom, is transported through the needle loom transversely with respect to the longitudinal direction of the needle bar 1 .
[0030] One end of a rigid first connecting rod 5 is rigidly connected to the side of the needle bar 1 facing away from the needles 2 . The other end of the connecting rod is supported on a first cam 6 of a first crankshaft 7 . The first crankshaft 7 is supported rotatably in a machine stand 8 of the needle loom, which also carries the needle-punching support surface 4 .
[0031] To guide the needle bar 1 up and down with respect to the needle-punching support surface 4 during operation, one end of a flexible guiding leaf spring 9 is rigidly attached to the needle bar. The other end of this guiding leaf spring 9 is attached rigidly to the machine stand. 8 .
[0032] During operation, the needle bar 1 is set into up-and-down motion with respect to the needle-punching support surface 4 by the first crankshaft 7 , operating by way of the first cam 6 and the first connecting rod 5 . As needle bar 1 executes this motion, it is guided by the elastic guiding leaf spring 9 , which bends elastically over its entire length but especially near the points where it is clamped to the needle bar 1 and to the machine stand 8 . Due to the stiffness of the first connecting rod 5 and its rigid connection to the needle bar 1 and due to restricting the needle bar 1 from sideways movement—a limitation which holds the bar in a position almost always directly below the first crankshaft 7 —the needle bar 1 executes a tipping movement around its longitudinal axis, which also leads to elastic flexing of the guiding leaf spring 9 . To minimize this tipping movement, the first connecting rod 5 should be as long as possible, that is, long in relation to the stroke of the needle bar 1 . To minimize the bending stress of the guiding leaf spring 9 , it should be as long as possible, that is, comparatively long in relation to the stroke of the needle bar.
[0033] FIG. 2 shows an exemplary embodiment of the invention in which the invention is realized in a needle loom comprising two needle bars 1 , which are arranged next to each other and which operate independently. Assigned to each needle bar 1 is its own punching drive, consisting of first crankshaft 7 , operating by way of first cam 6 and first connecting rod 5 . Each needle bar 1 , furthermore, is rigidly connected to one end of an individual guiding leaf spring 9 , the other end of which is rigidly clamped in the machine stand 8 . The two arrangements are mirror images of each other. Their behavior during operation is completely comparable to that already explained above on the basis of the example of FIG. 1 .
[0034] FIG. 3 shows a schematic diagram of an embodiment of a needle loom with two needle bars 1 , each of which has its own needle-punching drive, consisting of crankshaft 7 , operating by way of cam 6 and connecting rod 5 , in a manner completely comparable to the embodiment of FIG. 2 . For the sake of clarity, the needle-punching support surface 4 and most of the machine stand 8 are not shown. The only part of the machine stand 8 shown is the point where, when one end of a guiding leaf spring 9 is clamped, the other end is rigidly connected to one of the needle bars 1 , in the present case the needle bar 1 shown on the left hand side of the drawing. The two needle bars 1 are connected to each other on their facing sides by an elastic coupling leaf spring 10 , which is rigidly attached to the two needle bars 1 .
[0035] During operation, the rotation of the first crankshaft 7 leads to a rising and falling movement of the needle bars 1 . In addition, due to the rigid connection of the stiff first connecting rod 5 to the needle bars 1 and the limitation on the movement of the bars by the guiding leaf spring 9 and the coupling leaf spring 10 , needle bars 1 are tipped around their longitudinal axes, i.e., to the right and to the left in the drawing. The lateral guidance of the needle bar 1 shown on the left in the drawing is provided by the guiding leaf spring 9 attached to it, which behaves in the same way as guiding leaf springs 9 shown in FIGS. 1 and 2 . As shown in FIG. 3 , the lateral guidance of needle bar 1 shown on the right in the drawings is provided by the elastic coupling leaf spring 10 .
[0036] If the two first crankshafts 7 turn in the same direction, the coupling leaf spring 10 flexes into the shape of an “S”, that is, it bends in two opposite directions, because the needle bars tip in the same direction. If the two first crankshafts 7 turn in opposite directions, the coupling leaf spring 10 bulges out in only one direction, that is, first in the upward direction and then in a downward direction, which means that it is subject to less bending stress than that present in the first-mentioned operational variant. Counter-rotating operation of the first crankshafts 7 is preferred as it is easier to balance the inertia within the needle loom.
[0037] FIG. 4 shows another embodiment of the invention, which differs from the previously described embodiments primarily in that the unit consisting of first connecting rod 5 , which is moved by first cam 6 of first crankshaft 7 , and the needle bar 1 is not rigid. Instead, an elastic connecting leaf spring 11 is inserted between the free end of the connecting rod 5 and the needle bar 1 . The connecting leaf spring 11 is rigidly connected at one end to the first connecting rod 5 and at the other to the needle bar 1 . Connecting leaf spring 11 transmits the thrust forces for punching coming from the crankshaft 7 and is relatively short so that it does not buckle to the side under the effect of the thrust forces mentioned.
[0038] The lateral guidance of the needle bar 1 can in this case be accomplished by a guiding leaf spring 9 of the type shown in FIG. 1 . This variant is not shown in the example of FIG. 4 , but will be understood to be possible by one skilled in the art.
[0039] FIG. 4 shows, in contrast, a variant for the lateral guidance of the needle bar 1 by means of a second connecting rod 12 , which is moved by a second crankshaft 14 supported in the machine stand (not shown), acting by way of a second cam 13 . The second crankshaft 14 is arranged on approximately the same level as the needle bar 1 . The second connecting rod 12 and the needle bar together form a rigid unit. A rotation of the second crankshaft 14 at the same speed as that of the first crankshaft 7 is able superimpose a motion component oriented parallel to the needle-punching support surface onto the punching motion of the needle bar oriented essentially perpendicular to the base (not shown). During the time that the needles 2 remain in the web to be processed, this parallel component proceeds in the same direction as that of the web through the needle loom. Although it is true that, during this movement, the needle bar 1 also tips slightly around its longitudinal axis as a result of the rigid connection between the second connecting rod 12 and the needle bar 1 , nevertheless, if the second connecting rod 12 is long enough, the tipping angle is so small that it does not produce any noticeable disadvantageous effect in the processed web of material. A “long” connecting rod in this context means long with respect to the stroke of the needle bar 1 . The previously mentioned tipping movements of the needle bar 1 are absorbed by the elastic connecting leaf spring 11 , which flexes under the effect of the tipping movements.
[0040] In a manner fully comparable to that shown in FIGS. 1 and 4 , FIG. 5 shows the application of the features explained on the basis of the example of FIG. 4 to a needle loom with two needle bars 1 arranged next to each other. Each needle bar 1 has its own first drive for the needle-punching movement, consisting of a first crankshaft 7 , a first cam 6 , a first connecting rod 5 , and a connecting leaf spring 11 . In addition, each needle bar 1 has a second drive for the horizontal motion component oriented parallel to the needle-punching support surface 4 (not shown). The second drive consists of a rigid second connecting rod 12 , rigidly attached to the needle bar 1 , and a second cam 13 on a second crankshaft 14 , which is mounted on approximately the same level as the needle bar 1 . The arrangements are mirror images of each other. The way they function is the same as that described above in relation to the embodiment of FIG. 4 .
[0041] FIG. 6 shows an exemplary embodiment of the invention which is comparable to that of FIG. 3 with respect to function but which requires that the first crankshafts 7 turn in the same direction. It also differs in design from the embodiment in FIG. 3 in that each of the first connecting rods 5 are connected to the needle bar 1 by way of an elastic connecting leaf spring 11 —similar to the embodiment of FIGS. 4 and 5 . Another difference versus the embodiment of FIG. 3 is that the guidance of the needle bar 1 shown on the right in FIG. 6 is provided by two elastic coupling leaf springs 10 , which are arranged one above the other a certain distance apart, and each of which is rigidly connected to the needle bars 1 . Two coupling leaf springs 10 are required as a result of the elastic connection between first connecting rods 5 and needle bar 1 . In this embodiment, a certain freedom of movement is restrained which cannot be limited sufficiently by only a single coupling leaf spring according to the example of FIG. 3 .
[0042] In the preferred embodiments described on the basis of FIGS. 1-3 and 6 , both ends of the guiding leaf spring 9 are clamped rigidly in position, one end on the needle bar 1 and the other on the machine stand 8 , and in the bent states, i.e., when the needle bar is in its upper and lower end positions, the spring assumes a slightly “S”-like shape. According to the variant shown partially in FIG. 7 , the bending stress of the guiding leaf spring 9 can be reduced by supporting one end in a pivot bearing 15 . Preferably pivot bearing 15 is lubricated for life, that is, a bearing which requires little or no maintenance. In this case, the guiding leaf spring 9 shows only a simple form of flexure in the end positions of the needle bar 1 , and its overall bending stress is reduced in comparison with that present in the previously described exemplary embodiments.
[0043] FIG. 8 shows another preferred embodiment of the invention. This is similar to the exemplary embodiment of FIG. 1 to the extent that the needle-punching drive of the needle bar 1 consists of a first crankshaft 7 , which is connected to the needle bar 1 by way of a first cam 6 and a first connecting rod 5 rotatably supported thereon. The connecting rod 5 and the needle bar 1 , similar to the preferred embodiment of FIG. 1 , form a rigid unit. For the guidance of the needle bar 1 during its punching movement, a second crankshaft 14 is provided, which is rotatably supported in the machine stand (not shown) on approximately the same level as the needle bar 1 . The second crankshaft 14 has a second cam 13 , on which a second connecting rod 12 is rotatably supported. The second connecting rod 12 has a free end, which is connected to the needle bar 1 by a second elastic connecting leaf spring 16 . The second connecting leaf spring 16 has ends, one of which is rigidly connected to the needle bar 1 , the other to the free end of the second connecting rod 12 . With this design, a motion component oriented parallel to the needle-punching support surface (not shown in FIG. 8 ) can be superimposed on the punching movement of the needle bar in a manner completely comparable to the example of FIG. 4 . Such parallel movement again follows the forward movement of the web being processed in the needle loom during the time that the needles 2 remain in the web. The second connecting leaf spring 16 makes it possible for the needle bar to execute the tipping movements versus the needle-punching support surface which occur during operation as a result of the cams 6 and 13 acting by way of the connecting rods 5 and 12 . Again, the connecting rods 5 and 12 should be long in relation to the stroke of the needle bar 1 to minimize such tipping movements.
[0044] The exemplary embodiment of FIG. 9 shows a needle loom with two needle bars arranged next to each other, which are connected to each other by two elastic coupling leaf springs 10 . To this extent and also with respect to the needle-punching drives of the needle bars, this embodiment is the similar to that of FIG. 6 . The embodiment of FIG. 9 differs from that of FIG. 6 in that it adds a second drive to the two needle bars 1 , namely, a drive which gives the needle bars 1 a motion component parallel to the needle-punching support surface (not shown), as described on the basis of the example of FIG. 8 . The second drive comprises a second crankshaft 13 , supported in the machine stand on approximately the same level as the needle bar 1 , this crankshaft carrying a second cam 14 , on which a second connecting rod 12 is rotatably supported. The free end is connected to one of the needle bars 1 , namely, to the needle bar 1 shown on the left in the drawing, by means of a second connecting leaf spring 16 . The second connecting leaf spring 16 has two ends, one of which is rigidly connected to the second connecting rod 12 , the other to the previously mentioned needle bar 1 . The second connecting leaf spring 16 makes it possible for the left needle bar 1 to execute the tipping movements versus the needle-punching support surface which occur during operation as a result of the cams 6 and 13 acting by way of the connecting rods 5 and 12 , whereas the coupling leaf springs 10 make it possible for the two needle bars 1 to move with respect to each other. Again, the connecting rods 5 and 12 should be long in relation to the stroke of the needle bar 1 to minimize the previously mentioned tipping movements. To increase the stiffness, the needle bars 1 could be connected here by a diagonal strut (not shown), located in the area between the coupling leaf springs 10 . It is also contemplated that the interior area between the two needle bars 1 could be filled in completely by a wall of sheet metal, for example, to increase the stiffness.
[0045] It can be seen from the examples shown and explained above that the concept of the rigid connection between connecting rods and needle bars and the use of elastic leaf springs for guidance and also in the drive of the needle bars can be implemented in any desired way as long as it is ensured that at least one elastic leaf spring is used either to guide the needle bar or as part of the needle-punching drive. As a result of the invention, the need for lubrication is completely eliminated at least on the needle bar, which considerably reduces the effort required to lubricate the interior of the machine, as there is no need to introduce lubricant to the moving parts of the machine.
[0046] As has been explained above, it is desirable that the guide element, whether it be a second connecting rod with a second connecting leaf spring or a guiding leaf spring, be as long as possible in relation to the stroke of the needle bar. If the guide element is a guiding leaf spring 9 , it can easily, because of its length, start to oscillate under the effect of the up-and-down movement of the needle bar 1 . To suppress such natural oscillations, a guard 17 , which is shown in FIG. 10 and a detail of which is shown on a larger scale in FIG. 11 , is provided according to an elaboration of the invention.
[0047] According to FIG. 10 , the preferred embodiment with a guard 17 for a guiding leaf spring 9 consists of two stiff rails 18 , which are arranged parallel to each other and which are connected to each other by several pairs of rods 19 . The connecting rods 19 of one pair form a gap, through which the guiding leaf spring 9 extends, and the longitudinal edges of the spring rest on the rails 18 . If the rails 18 are flat, at least three pairs of connecting rods 19 must be present, as shown in FIG. 10 , to suppress the natural oscillations of the guiding leaf spring 9 . If the stroke frequency of the needle bar 1 arrives in a range in which the guiding leaf spring 9 could be caused to oscillate harmonically, the number of pairs of connecting rods 19 will have to be increased correspondingly.
[0048] Alternatively, the rails 18 could have a C-shaped cross section, wherein the side pieces of the rails face each other. If the guiding leaf springs 9 are embedded in soft plastic or rubber provided in the groove between the side pieces of a rail 18 , the connecting rods 19 can then under certain conditions be omitted entirely. The leaf spring in this case has sufficient freedom to flex in the groove and yet is still securely supported.
[0049] Because the ends of the guard 17 can come in contact with adjacent machine parts, the ends of the rails 18 are preferably provided with buffers 20 of rubber or plastic to dampen the noise which would otherwise occur during operation.
[0050] Reference throughout this specification to “one embodiment,” “an embodiment,” “a preferred embodiment,” “alternate embodiment” or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases “in one embodiment,” “in an embodiment,” “in a preferred embodiment,” “in an alternate embodiment,” and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment.
[0051] Furthermore, the described features, advantages, and characteristics of the invention may be combined in any suitable manner in one or more embodiments. One skilled in the relevant art will recognize that the invention may be practiced without one or more of the specific features or advantages of a particular embodiment. In other instances, additional features and advantages may be recognized in certain embodiments that may not be present in all embodiments of the invention.
[0052] While the present invention has been described in connection with certain exemplary, alternate or specific embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications, alternatives, modifications and equivalent arrangements as will be apparent to those skilled in the art. Any such changes, modifications, alternatives, modifications, equivalents and the like may be made without departing from the spirit and scope of the invention.
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The drive and guide device for a needle bar of a needle loom having a machine stand includes a first crankshaft rotatably supported in the machine stand; a needle bar supported in the machine stand; a first connecting rod supported on a first cam of the first crankshaft and connected to the needle bar; and a guide device for guiding the needle bar along a path extending perpendicular to the needle-punching support surface. The first connecting rod and/or the guide device comprises a leaf spring, which is rigidly connected to the needle bar to transmit a drive or guide force. As a result, lubrication points on elements of the needle loom which move from place to place are eliminated.
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BACKGROUND AND SUMMARY OF THE INVENTION
[0001] This invention relates to surface film laminates used in roofing membranes adapted for the waterproofing and sealing of substrate structures, particularly in roofing applications and to the method of manufacturing such membranes. More particularly, the present invention is in the field of energy-efficient roofing membranes and shingles based on atactic polypropylene modified or styrene-butadiene-styrene modified or thermoplastic polyolefin modified bituminous compound, with a factory-applied surface film laminate of the present invention that provides high reflectivity and emissivity on the weathering surface of the membrane, resulting in reduced energy needed to maintain optimal building temperatures, effecting significant economical and environmental benefits, in addition to complying with the requirements of various regulatory bodies.
[0002] Energy consumption and costs have received much attention because when energy prices go up, a corresponding need has arisen for roof systems that assist in energy conservation. There has been a need for a roofing material with high reflectivity and high emissivity, especially in regions where cooling-degree days exceed heating-degree days. Several studies have been conducted that correlated the surface temperature of a building's roof to the energy required to maintain comfortable living conditions inside the building. Such studies have revealed that cooler roofs resulted in lower energy costs associated with heating the interior of the building. After extensive research and analysis, several governmental and non-governmental entities, research organizations, regulatory bodies and building standards-setting organizations have recognized the significance of benefits associated with energy savings through the use of cool roofing materials that help lower energy costs by maintaining lower surface temperatures. One of the several energy programs that have been recently launched is the Energy Star program implemented by the U.S. Department of Energy and the U.S. Environmental Protection Agency. Energy Star program is a national campaign to help protect the environment through energy efficient products and practices. Other nationwide programs include the Leadership in Energy and Environmental Design (LEED) program, ‘Green Roof’ program, ‘Cool Communities’ program coordinated by the U.S. Department of Energy, etc. Several local jurisdictions have also launched energy efficient roof programs. In 1994, the State of Georgia enacted what has come to be known as the Georgia White Roof Amendment that requires the use of additional insulation for roofing systems whose surfaces do not have test values of 75% or more for both reflectivity and emissivity. In January of 2001, California launched its California Energy Commission's Cool Savings Program to allocate money towards the use of cooler roofing systems. The program, which is the first of its kind, grants a building owner a rebate of up to 20 cents/foot 2 of roof surface that contains cool roofing materials. Similarly, the Sacramento Municipal Utility District has instituted a rebate program to contractors of up to 20 cents/foot 2 for roof products that contain cool roofing materials. The city of Tucson, Ariz. is investigating ‘cool community’ mitigation measures to reduce heat island effect of hot roofing and paving materials. Other jurisdictions have gone even further by making energy efficient roofing program mandatory on all new roof installation. For example, the City of Chicago has enacted a new ordinance that requires the use of roofing materials to meet stringent requirements for energy efficiency such as 65% initial solar reflective properties and 50% solar reflective properties after three years, and 90% emissivity. Several other metropolitan areas are set to follow these examples.
[0003] The term “cool roof” is used in the trade, in general, to refer to a roof surface that is highly reflective and highly emissive. A roof surface's primary characteristics that are critical to energy performance are solar reflectivity and emissivity. Reflectivity, also known as albedo, is the amount of incoming solar energy a roofing material's surface reflects and is measured as a percentage of solar heat reflected off of the roof. Emissivity is the amount of absorbed energy a roofing material radiates from itself because of the material's own heat and temperature, and is measured as a percentage of heat that comes off of a roof. In other words, reflectivity is the percentage of the sun's heat a roof keeps off the building structure, whereas emissivity is the percentage of heat a roof lets out of a building structure.
[0004] For a building to have improved thermal efficiency its roof system should have a high reflectivity, i.e., it should keep out a high percentage of the solar energy to which it is exposed, and the roof system should have high emissivity, i.e., it should let out a high percentage of the heat it has absorbed. Most surfaces have high reflectivity but low emissivity and vice-versa. For example, black asphaltic surface has low reflectivity but high emissivity, whereas aluminum metallic roof surface has high reflectivity but low emissivity. Conventional roof surfaces with low reflectivity and high emissivity heat to 160 to 190 degrees Fahrenheit during the summer. Metal or aluminum coated roofs with high reflectivity and low emissivity still warm to 140 to 170 degrees Fahrenheit. Cool roofs with both high reflectivity and high emissivity only reach 100 to 120 degrees Fahrenheit in the summer sun.
[0005] In order to qualify as a cool roof, it is essential for the roofing material to possess both high reflectivity and high emissivity characteristics. Reflectivity is measured using ASTM E903 or ASTM E1918 and emissivity is determined in accordance with ASTM E408. A cool roof, as defined by the U.S. Department of Energy as part of its Energy Star program, is a roof made with a product that meets or exceeds the Department's solar reflectance requirements, without compromising product quality or performance. Energy Star labeled roof product is a reflective roof material that lowers roof surface temperature by up to 100 degrees Fahrenheit, thereby decreasing the amount of heat transferred into a building's interior. Energy Star labeled roof product provides several benefits, including cost and energy savings, extended roof life, and decreased pollution.
[0006] Roofs undergo significant expansion and contraction as they heat and cool throughout the day. Heat absorbed can accelerate degradation due to UV rays and water. Reflective roof can reduce the amount of thermal shock that occurs on the roof surface and make the roof last longer. Also cool roofs are long lasting because they reflect the sun's ultraviolet rays that are responsible for breakdown of most conventional materials.
[0007] To summarize, cool roofs offer many benefits, including decreased roofing maintenance and replacement costs, improved building comfort, reduced impact on surrounding air temperatures, reduced peak electricity demand, reduced waste stream of roofing debris due to extended roof life, etc.
[0008] Reflectivity and emissivity are dependent on the surface characteristics of the roofing membrane. Uncoated APP and SBS modified roofing membranes have reflectivity values of 0.05 to 0.10 whereas white granulated roofing membranes possess reflectivity in the range of 0.20 to 0.40. There are several coatings that are available in different colors that can be applied to the exposed surface of the sheet to improve the reflectivity and emissivity factors. Modified bitumen roofing products do not meet criteria for cool roofing without application of external coatings on the top surface of the roofing membrane after installation of the same at the jobsite. Such external treatment that is generally in the form of coatings has several drawbacks. Coatings are generally sprayed or rolled onto the main roof's surface area and are difficult to handle. These emit volatile organic compounds (VOC) that are harmful to the environment. Coatings are very expensive, and the process of application of coatings is labor intensive and time-consuming because of extensive surface preparation required. Most manufacturers of coatings stipulate stringent requirements for preparation of the surface of the membrane before application of the coatings—such instructions, when improperly followed, result in not achieving the desired results. Also most coatings are recommended to be applied a few days after installation of the roofing membrane, which extends the time needed for prompt completion of the roofing project. Moreover, most coatings lose their effectiveness in 5-8 years and therefore the roof needs to be recoated to attain the desired reflective and emissive properties. Also the amount of coating applied is very subjective; it depends on several factors such as the laborer, type of membrane, surface texture of the membrane, etc. All of the above factors determine the effectiveness of the performance of coatings over a period of time.
[0009] Although there are film materials commercially available that possess high reflective and high emissive properties, such films cannot be directly applied to the asphaltic compound due to a variety of reasons, such as processing difficulties due to heat sensitivities of the film, potential for delamination of the film caused by exudation of oil from modified asphaltic compound, discoloration of the film due to exudation of oil from modified asphaltic compound, etc. A roofing material with a metallic or aluminum top layer and a bitumen coating bottom layer is known in the prior art. For example, U.S. Pat. No. 5,096,759, discloses a membrane containing a laminated top aluminum foil surface and a bottom bitumen coating surface. The surface film laminate applied on the top layer of the membrane to impart cool roof properties constitutes the weathering surface. Such film can a lamination of multiple layers consisting of fabric, foil and film materials. The fabric material generally used is commercially available polyester or polypropylene that is utilized in a variety of applications including roofing, furniture, etc. Aluminum foil used is of commercial grade widely used in the manufacture of food packaging to ensure freshness of the contents since such foil offers excellent barrier characteristics. Film employed can be polyester (polyethylene terephthalate—PET) or polyvinyl fluoride (PVF). Polyester (PET) in sheet form has multiple applications and is widely used. PVF preferred is a special grade produced by DuPont De Nemours & Company under the trade name, Tedlar. Tedlar possesses excellent properties such as high reflectivity, high emissivity, excellent ultraviolet light resistance, good heat resistance, fire retardancy, good dimensional stability, good bonding characteristics to various substrates using adhesives, resistance to attack by solvents, fungi, etc. This material also has proven outdoor exposure and owing to such excellent properties, this material is widely used in outdoor applications. To avoid differential stresses arising from changes in temperature, the various substrates are preferably made of materials having similar or identical thermal expansion properties. Several laminating companies can be used for the production of such laminates.
[0010] There are currently several products available in the market that have fabric material on the top surface of the asphaltic compound in order to provide high temperature resistance and anti-slip properties. It is well known that most coatings used to meet cool roof criteria are silver or white in color. In order to obtain a silver color finish, it is possible to metallize one or both sides of a fabric material which can be made of polypropylene or polyester. Alternately a white color fabric can be used to get a white color finish. The advantage of using a fabric over other materials such as film or foil is that their coarse texture assists in adhering the surface film laminate to the asphaltic substrate. Film or foil materials typically have very smooth surfaces, which may provide insufficient surface area for bonding, and therefore could delaminate from the surface of the asphaltic compound after cooling of the roofing membrane.
[0011] Coincidentally, polyester fabric has thermal expansion characteristics similar to that of the modified bituminous compound. Moreover, it is noteworthy that one of the preferred choices of reinforcing carrier in a modified bituminous roofing membrane is polyester. Another reason for choosing polyester fabrics is because they are relatively inexpensive. However, fabrics are not designed for outdoor applications, and therefore do not have long life when exposed to the elements, and hence will fail in a short period. Failure could be caused by a variety of factors such as ultraviolet light, moisture, attack from solvents and fungi, foot traffic, migration of oil and plasticizers in the modified bituminous compound causing delamination, etc.
[0012] For purposes of the present invention, the preferred materials are polyester (PET) or polyvinyl fluoride (PVF) and foil such as aluminum. Aluminum has its advantages in that it is readily available and is affordable. It also has good bonding characteristics to surfaces such as fabrics, good impermeability and excellent reflective properties. The main drawback associated with aluminum foil is its relatively low emissive characteristics. Moreover, use of a thin layer of aluminum can cause the surface film laminate to fail by erosion or damage due to traffic. Conversely, use of a thicker foil increases cost in addition to posing other problems such as the product becomes very rigid and difficult to handle.
[0013] The present invention offers a surface laminate that meet the requirements of high reflectivity and high emissivity required for conventional roofing membranes and shingles to qualify as ‘cool roofs’ without the drawbacks associated with the usage of coatings. The laminate of the present invention is made in the factory (saving labor costs in the field and providing quality control that is not available when field applied coatings are used) and has several advantages in that it is environmentally friendly, relatively inexpensive, highly reliable, and does not involve additional time for installation of the roof. Such treatment is performed under rigid factory conditions and is not subject to the numerous variables in the field as with application of an external coating. The surface laminate that is the subject of this invention provides enhanced reflectivity and emissivity because of its unique design features. This inventive laminate can be used on APP modified and SBS modified membranes, self-adhesive membranes, underlayments such as employed under tile roofing and metal panels, as well as on shingles.
[0014] It is important to note that “cool roof” requirements for shingles are not as stringent as for modified membrane roofing, i.e., the reflectivity and emissivity requirements are lower for shingles that for membranes for flat roofs. Table 1 provides the requirements of the Energy Star program for roofing products and Table 2 provides the requirements of the City of Chicago for cool roof products. This is due to the fact that shingles are applied on steep slope, which is defined as a roof pitch of 2:12 inches and greater. Though the present inventive films are silver or white colored, which may not be desirable in residential applications, it is possible to have sufficiently reflective and emissive films in a variety of other colors for use in shingle roofing for residential applications.
[0015] It is, therefore, one object of the present invention to provide a high reflective and high emissive surface laminate that can be applied to the top surfaces of roofing membranes to prevent heat from being absorbed by the roofing material by enhancing reflectivity and emissivity characteristics.
[0016] Another object of the present invention is to provide a high reflective and high emissive surface laminate that can be applied to the top surfaces of roofing shingles to prevent heat from being absorbed by the material by enhancing reflectivity and emissivity characteristics.
[0017] Yet another embodiment of the present invention is to provide a high reflective and high emissive surface laminate in the form of a seam tape that can be used in repair or patching work on existing and new roofing structures. Such seam tapes are usually 6 to 12 inches in width. When torch grade cool roofing modified membranes are applied on the rooftop, the backside of one roll is torched and attached to the overlap area of an adjacent roll. Similarly when mop grade cool roofing modified membranes are applied on the rooftop, the backside of one roll is hot mopped and attached to the overlap area of an adjacent roll. During this process of application, the laminate surface on the overlap areas (i.e. the side lap and end lap) of the composite membrane could experience heat distortion. Seam tapes of the present invention could be applied over the end lap and side lap joint areas to provide a continuous cool roofing membrane covering. Use of such seam tape also serves the purpose of protecting the exposed edges of the membrane from deterioration due to ultraviolet rays.
[0018] In one preferred embodiment, the surface laminate of this invention is a hybrid of a polyolefinic fabric and a polyolefinic sheet material, bonded together using a bonding adhesive, with or without a coating of an ultraviolet resistant material on the exposed side of the top layer. In another preferred embodiment, the surface laminate of this invention is a hybrid of a polyolefinic fabric, a polyolefinic sheet and an aluminum foil, bonded together using bonding adhesive, with or without a coating of an ultraviolet resistant material on the exposed side of the top layer. The polyolefinic fabric can be made of polypropylene or polyester, of unit weight ranging from 15 grams/meter 2 to 250 grams/meter 2 , depending upon the method of application to the modified bituminous substrate. Bonding adhesive used as bonding agent can be low density polyethylene (LDPE), acrylic adhesive or ethyl acrylic acid (EAA), of thickness in the range of 0.5 mil (12.5 microns) to 1.5 mil (37.5 microns). Polyolefinic film on the top surface can be commercially available polyester (PET) or Polyvinyl fluoride (PVF), of thickness ranging from 1 mil (25 micron) to 2 mil (50 micron), clear or white in color, depending upon the desired color of the laminate, and with or without ultraviolet inhibitors inside the polymeric material. Clear polyolefinic film can be metallized using vapor deposition techniques to yield a silver color look. Aluminum foil used is commercially available grade of 1 mil in thickness. To avoid differential stresses arising from changes in temperature, the various substrates are preferably made of materials having similar or identical thermal expansion properties.
[0019] Fabric employed in this application can be polypropylene or polyester based. However, due to the superior thermal characteristics of the polyester material, fabric selected for this lamination was a polyester of unit weight ranging from 30 to 250 grams/meter 2 depending on the preferred method of subsequent lamination of the surface film to the modified bituminous compound. If the preferred mode of manufacture of the ‘cool roof’ modified bitumen membrane is by laminating the surface film laminate of the present invention to the top of the modified bitumen compound, a 30 to 50 grams/meter 2 polyester mat is preferred. However, if the preferred mode of manufacture of the ‘cool roof’ modified bitumen membrane is by coating the modified bitumen compound on the surface film laminate of the present invention, a 140 to 250 grams/meter 2 polyester mat is preferred.
[0020] Polyolefinic film can be polyester (PET) or polyvinyl fluoride (PVF) material. However, there are significant differences in cost and performance characteristics of PET and PVF sheets. While both have good inherent ultraviolet resistant properties, PVF film is 6 to 10 times costlier than its PET counterpart. Both films are available in a variety of colors. However this invention focuses on white and silver color film surfaces. It is noteworthy that white and silver color sheets meet the high reflectivity and emissivity requirements whereas other colors do not. However other colored sheets may be suitable for use in cool roofing shingles, which require significantly lower reflectivity and emissivity values. See Table 1 and 2 for minimum acceptance values. The success of the surface laminate depends primarily on the ultraviolet resistant nature of the polyolefinic film. White sheets have pigments such as titanium di-oxide added in order give the white color, and the pigment is carried by a sheet. “Carried by”, as used herein includes mixed into the material comprising a sheet and applied as a coating to a sheet. Such films are opaque and do not allow UV light to pass through them. These films are also available with built-in ultraviolet inhibitors to absorb any UV light that may enter inside.
[0021] Another important factor when choosing a sheet is thickness. A minimum of 1 mil (25 micron) is required to achieve the desired properties. Use of a thin sheet can cause premature failure through erosion or damage by traffic. Use of a thicker sheet dramatically increases cost in addition to posing other problems in that the product becomes very rigid and difficult to handle. A PVF sheet of 1 mil (25 micron) thickness was selected for this application due to its proven outdoor weatherability, high reflectivity, high emissivity, excellent ultraviolet light resistance, good heat resistance, fire retardant properties, good dimensional stability, good bonding characteristics to various substrates using adhesives, resistance to attack by solvents, fungi, etc. A white color PVF sheet is used to get a white color film laminate surface and a metallized, clear PVF sheet or clear PVF film/aluminum foil combination is used to give a silver color surface laminate. After metallization of the PVF film using vacuum metal deposition technique to achieve silver color finish, such sheets are oriented in a manner that the metallized surface faces downward in the direction of the PET fabric, i.e., the metallized surface comes into contact with the bonding adhesive. Because the sheet is metallized on its underside, the silver color is protected from becoming discolored or damaged during manufacture and installation of the roofing membranes. Also, metallizing the underside permits the metallized surface not to be exposed to the elements where it might be eroded by action of the weather or wear away by foot traffic.
[0022] Aluminum foil employed is of commercially available grade of thickness ranging from 0.5 mil to 1.5 mil, with a preferred thickness of 1 mil. Such foil can be specially formulated with alloys to give added flexibility to the structure in order to facilitate ease of manufacture and ease of application of the roofing membrane at the jobsite.
[0023] The various layers can be bonded together with an adhesive such as acrylic or ethyl acrylic acid (EAA) or low density polyethylene (LDPE). While an acrylic adhesive is the most expensive option, it provides the best bonding strength based on prior art. Acrylics have excellent emissive properties as well. Since bonding strength is very important for the long-term performance of the membrane, the preferred bonding agent is a clear, acrylic adhesive of thickness 0.5 mil (12.5 microns) to 1.5 mil (37.5 microns). Such adhesives can also consist of UV stabilizers. UV stabilizers can be added to the adhesive to prevent delamination of the film from the fabric in case of attack of the adhesive layer due to UV light penetration through the existing upper layers.
[0024] The exposed surface of this surface laminate can be coated with an external layer of an ultraviolet resistant low density polyethylene or other proprietary ultraviolet resistant coatings in the order of 0.5 mil (12.5 microns) to 1 mil (25 microns) thickness to impart an additional layer of protection from ultraviolet light. An added advantage of using a UV resistant coating based on low density polyethylene (LDPE) is that LDPE has excellent emissive properties as well.
[0025] Furthermore, the upper surface of the laminate is preferably embossed to enhance aesthetics, provide slip resistance to the surface in addition to masking any surface imperfections.
[0026] When such film laminates are applied to the top asphaltic compound layer of modified bitumen membranes, roofing products that meet high reflectivity and emissivity criteria for cool roofing is achieved.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] [0027]FIG. 1 shows an embodiment of the inventive silver surface film laminate.
[0028] [0028]FIG. 2 shows an embodiment of the inventive white surface film laminate.
[0029] [0029]FIG. 3 shows another embodiment of the inventive silver surface film laminate.
[0030] [0030]FIG. 4 shows another embodiment of the inventive white surface film laminate.
[0031] [0031]FIG. 5 shows an embodiment of the inventive surface film laminate to be used as a seam tape.
[0032] [0032]FIG. 6 shows another embodiment of the inventive surface film laminate to be used as a seam tape.
[0033] [0033]FIG. 7 is a process of manufacture for one embodiment of the inventive surface film laminate.
DETAILED DESCRIPTION OF THE INVENTION
[0034] [0034]FIG. 1 shows one embodiment of the surface laminate 1 , which is silver in color. A PET fabric 2 is laminated to a translucent and preferably clear, PVF sheet 3 using an adhesive 4 . The underside 5 (hereinafter also referred to as metallized surface 5 ) of the PVF sheet 3 is metallized using a metal deposition technique (such as vapor deposition, perhaps in vacuum) to give a silver color to the laminate in order to establish reflectivity. The metallized PVF sheet 3 is oriented such that the metallized surface 5 faces downward in the direction of the PET fabric 2 , i.e., the metallized surface 5 comes into contact with the bonding adhesive 4 . An UV resistant coating 6 is applied on the upper side 8 of the PVF sheet 3 and an emboss pattern 7 can be applied on the top surface to enhance aesthetics and provide anti-slip properties. The preferred embodiment of a silver colored laminate surface 1 is a metallized, clear polyvinyl fluoride (PVF) sheet 3 of 1 mil (25 microns) thickness, with built-in ultraviolet inhibitors to prevent UV degradation, with or without a 0.7 mil thick clear, UV inhibiting coating 6 on the top surface. This metallized sheet 3 is then laminated to a polyester fabric 2 using a clear, adhesive 4 of 0.5 mil (12.5 microns) to 1.5 mil (37.5 microns) thickness. The surface laminate 1 has a thickness between 6 mil (0.15 mm) and 10 mil (0.25 mm).
[0035] Another embodiment of the surface laminate is shown in FIG. 2, which is white in color. A PET fabric 9 is laminated to a white PVF sheet 10 using an adhesive 11 . An UV resistant coating 12 is applied on the exposed side of the PVF sheet 10 and an emboss pattern 13 can be applied on the top surface to enhance aesthetics and provide anti-slip properties. Although it is not necessary to metallize the bottom surface of the PVF sheet 10 , metallization is preferred in order to block any UV light from penetrating to the adhesive layer. Of course, the metallized PVF sheet 10 is oriented such that the metallized surface faces downward in the direction of the PET fabric 9 , i.e., the metallized surface comes into contact with the bonding adhesive 11 . The preferred embodiment of a white surface laminate 8 is a metallized, white polyvinyl fluoride (PVF) sheet 10 of 1 mil (25 microns) thickness, with built-in ultraviolet inhibitors to prevent UV degradation, with or without a 0.7 mil thick clear, UV inhibiting coating 12 on the top surface. This metallized sheet 10 is then laminated to a polyester fabric 9 using a clear, adhesive 11 of 0.5 mil (12.5 microns) to 1.5 mil (37.5 microns) thickness. The surface laminate 8 has a thickness between 6 mil (0.15 mm) and 10 mil (0.25 mm).
[0036] Furthermore, a white surface laminate 8 can be achieved by choosing a bonding adhesive 11 that is white in color. The white bonding adhesive provides the white color to the laminate, rather than having to use a white-colored sheet. Alternatively, to obtain the white colored laminate surface 8 , a white UV inhibiting coating can be applied on the top surface while using a clear PVF sheet 3 and clear adhesive 4 . The white UV inhibiting coating on the top surface provides the white color to the laminate surface 8 .
[0037] As shown in FIG. 3, another embodiment of the silver surface laminate 14 is a hybrid of a polyester fabric 15 , aluminum foil 17 and a PVF sheet 19 bonded using an adhesive 16 and 18 . The use of a mid-layer of aluminum foil 17 is to provide an additional barrier against migration of oil and plasticizers to the top surface of the structure and penetration of ultraviolet rays to the bottom surface of the structure. This construction can be coated with an external layer of an ultraviolet resistant polyethylene coating 20 or other proprietary ultraviolet resistant coatings of 0.5 mil (12.5 microns) to 1 mil (25 microns) thickness. An added advantage of using a coating 20 based on low density polyethylene (LDPE) is that LDPE has excellent emissive properties as well. A geometric pattern 21 can be embossed on the top surface of this sheet to enhance aesthetics, provide slip resistance to the surface in addition to masking any surface imperfections. Contrary to the prior embodiment, it is not necessary to metallize the surface to get the silver finish since the mid-layer, i.e., the aluminum foil 17 , is silver in color, and therefore the laminate 14 will appear silver on the top surface. The preferred embodiment of such laminate 14 is a clear PVF sheet 19 of 1 mil (25 microns) thickness, with built-in ultraviolet inhibitors to prevent UV degradation and a 0.7 mil (17.5 microns) thick clear, UV inhibiting coating 20 on the top surface, laminated using a clear, bonding adhesive 18 of 1.5 mil (37.5 microns) thickness to a 1 mil (25 micron) thick aluminum foil 17 , which in turn is laminated using a clear, bonding adhesive 16 of 1.5 mil (37.5 microns) thickness to a polyester fabric 15 . Such surface laminate 14 preferably has a thickness in the range of 6 mil (0.15 mm) to 10 mil (0.25 mm). It is noteworthy that the clear sheet 19 of this embodiment is not metallized due to an added layer of silver color aluminum foil 17 .
[0038] [0038]FIG. 4 illustrates another embodiment of a white surface laminate. The preferred embodiment includes a white PVF sheet 27 of 1 mil (25 microns) thickness, with built-in ultraviolet inhibitors to prevent UV degradation and a 0.7 mil thick clear, UV inhibiting coating 28 on the top surface, laminated using a clear, bonding adhesive 26 of 1.5 mil (37.5 microns) thickness to a 1 mil (25 microns) thick aluminum foil 25 , which in turn is laminated using a clear, bonding adhesive 24 of 1.5 mil (37.5 microns) thickness to polyester fabric 23 . Furthermore, a white color laminate surface 22 can be achieved by choosing a bonding adhesive 24 that is white in color. The white adhesive provides the white color to the laminate, rather than having to use a white-colored sheet. Alternatively, to obtain the white colored laminate surface, one can apply a white UV inhibiting coating 28 on the top surface while using a clear PVF sheet 19 and clear adhesive 24 . The white UV inhibiting coating 28 on the top surface provides the white color to the surface laminate 22 .
[0039] [0039]FIG. 5 shows another embodiment of the present invention, which is a seam tape 30 that is made from the abovementioned laminates. Such seam tape 30 can be white or silver surface laminates 31 and cut into narrower widths, preferably 6-9 inches. These tapes can be coated with a pressure-sensitive adhesive 32 on the bottom surface and a silicone release agent 33 on the top surface and self-wound.
[0040] [0040]FIG. 6 shows another embodiment of a seam tape 34 which consists of a PVF sheet 35 that is treated with a pressure-sensitive adhesive 36 on one side and a silicone release agent 37 on the opposite side. Such tapes are cut into narrower widths, such as 6 to 9 inches, and are self-wound.
[0041] [0041]FIG. 7 illustrates the process of manufacture of a surface laminate. Based on the desired color, white or clear, metallized PVF sheet is unwound from a unwinding station 38 . A bonding adhesive of desired thickness is applied at the adhesive applicator 39 . Coating thickness is precisely controlled using automated systems. After this application, the adhesive is allowed to cure by air cooling. PET fabric is applied to the adhesive side of the sheet at the fabric applicator 41 . This laminate is pressed using press rollers and then wound into rolls at the winder 42 . In case of silver laminate, a clear, PVF sheet is metallized on one surface in a separate process before this lamination. Such metallized sheet is loaded at the unwinding station 38 such that the metallized surface will be adhesive coated at the adhesive applicator 39 . The production of a surface laminate comprised of fabric, foil and sheet is performed as a two-step process. PVF sheet and aluminum foil are initially bonded together using an adhesive. The aluminum foil surface of such laminate is in turn laminated to a PET fabric using an adhesive and such structure is subsequently wound into rolls.
[0042] A seam tape may be obtained by slitting any of the above-mentioned sheets into narrower widths using a slitting device. Seam tape with the aforementioned reflectivity and emissivity may be used around the base of chimneys and other roof penetrations, and may be used to repair or supplement a lap joint.
[0043] The foregoing detailed description shows examples of embodiments of the present inventions. It will be understood by those of skill in the art that the inventions described herein, as claimed below, may be practiced in a number of alternative ways and that variations and modifications from the embodiments shown and described herein may still embody the spirit and scope of the appended claims.
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A reflective and emissive surface film laminate specially designed to form a top surface of modified bituminous roof covering composite such as membranes, underlayments and shingles to constitute a roof with thermal characteristics with substantially reduced amount of radiant energy entering a structure with such a covering.
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