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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an apparatus for vertically supporting pipes in oil production rigs, wherein the apparatus includes an outer frame and a centering device.
2. Description of the Related Art
Apparatus of the above-described type are used particularly on off-shore drilling platforms in order to lower the necessary pipes when carrying out drilling procedures. It is necessary in that process to clamp the pipes at certain points in time from the outside and to secure the pipes and, at other times, to release the clamping action and to lower the pipes for carrying out a lowering process.
Apparatus which have become previously known are not sufficiently able in a simple manner to vertically support pipes with different diameters and to carry out a support of pipes which are long and, thus, very heavy.
SUMMARY OF THE INVENTION
Therefore, it is the primary object of the present invention to construct an apparatus of the above-described type in such a way that it can be universally used.
In accordance with the present invention, at least one wedge device for clamping the pipe is arranged in the area of an inner side of the outer frame.
The arrangement of the wedge device in the area of the inner side of the outer frame makes it possible in a simple manner to clamp and release the pipe by a vertical movement of the wedge device. The wedge device clamps the pipe relative to the outer frame. It is possible in particular to use in a simple manner wedge devices having different sizes in the outer frame and, thus, to effect an adjustment to different outer diameters of the pipes, wherein these procedures take little time and material. In particular, it is not necessary to exchange large and heavy structural components.
Putting in place a pipe from the side is made possible by constructing the outer frame of several parts.
In particular, the outer frame may be constructed of two parts. For providing a high mechanical load bearing capacity in a radial direction, it is proposed that the parts of the outer frame are mechanically connected to each other.
Placing the pipe in the support device from the side is made easier and the manipulation is simultaneously simpler by providing the outer frame with an access door.
An alignment of the pipe relative to the support apparatus is made possible by the fact that the outer frame is connected to the centering device in the area of its vertically upwardly directed extension.
Placing the pipe in the support apparatus is also facilitated by constructing the centering device of several parts.
In particular, the centering device is constructed of two parts.
The manipulation by means of lifting devices is made possible by the fact that the centering device is slewable and connected to the outer frame.
The support of the pipes with high support forces is achieved by providing the wedge device with a positioning device and at least one carrier provided with at least one wedge.
For an adaptation to pipes to be supported having different sizes, a particular feature provides that the outer frame is optionally provided with a wedge device selected from a set of wedge devices having different sizes.
Also, contributing to the universal construction of the apparatus is the fact that the carrier is selected from a set of carriers having different sizes.
A positioning at high force applications is facilitated by providing the positioning device of the wedge device with at least one hydraulic cylinder for setting the position.
The parts can be secured by attaching at least two wedges to the carrier using at least one support element.
A clamping action without play is achieved by providing the wedge device with three carriers.
A maintenance-free long-term operability is facilitated by connecting the wedge device to a central lubricant supply.
A further improvement of the universal utility of the apparatus for different pipe sizes and different pipe weights can be achieved by providing the outer frame on an outer side thereof with at least one outer adapter for size adjustments.
Moreover, a simple manipulation is effected by providing guide recesses for receiving hinge bolts for connecting the access door to the other frame, wherein the guide recesses have a length which is greater than a width thereof.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of the disclosure. For a better understanding of the invention, its operating advantages, specific objects attained by its use, reference should be had to the drawing and descriptive matter in which there are illustrated and described preferred embodiments of the invention.
BRIEF DESCRIPTION OF THE DRAWING
In the drawing:
FIG. 1 is a perspective side view of an outer frame with closed access door and with a closed centering device;
FIG. 2 is a perspective side view of the outer frame of FIG. 1 shown with the centering device removed and the access door open;
FIG. 3 is a perspective view of the outer frame of FIG. 1 ;
FIG. 4 is a perspective view of the access door of FIG. 1 shown with hinge bolts removed;
FIG. 5 is a partial top view, on a larger scale, of the outer frame with the access door for illustrating the support sleeves for the hinge bolts;
FIG. 6 is a view similar to FIG. 5 , shown with inserted access door and the hinge bolts in an untensioned state;
FIG. 7 shows the arrangement of FIG. 6 after tensioning by wedging a pipe to be supported;
FIG. 8 is a perspective view of an outer frame with the centering device being folded up and the access door being open;
FIG. 9 is a partial view of the arrangement of FIG. 8 with the access door being closed with a carrier being inserted in the wedge device;
FIG. 10 is a perspective view of the outer frame for illustrating the use of outer adapter pieces;
FIG. 11 is an illustration similar to FIG. 10 for illustrating the use of outer adapter ring segments;
FIG. 12 is a side view of an outer frame with the access door being closed and a centering device placed on the outer frame;
FIG. 13 is a top view in the viewing direction XIII in FIG. 12 ;
FIG. 14 is an illustration similar to FIG. 13 with the access door being open;
FIG. 15 is another perspective illustration of an outer frame with the access door being removed and an outer adapter ring being used;
FIG. 16 is a schematic top view of an outer frame with the access door being closed and with a wedge device with three carriers;
FIG. 17 is a perspective view of a carrier of the wedge device with appropriate wedges and adapter segments;
FIG. 18 is a view of the carrier according to FIG. 17 after the insertion of the wedges and the adapter segments;
FIG. 19 is an exploded view of an outer frame with the required access door, centering device, and carriers of the wedging device;
FIG. 20 is a top view of an apparatus with a dividable outer frame;
FIG. 21 is a perspective side view of the apparatus of FIG. 20 ; and
FIG. 22 is a perspective view of a dividable outer frame.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 of the drawing shows a perspective view of an apparatus for vertically supporting a pipe, not shown. The apparatus includes an outer frame 1 and a centering device 2 . The centering device 2 is arranged vertically aligned above the outer frame 1 . The outer frame 1 is essentially U-shaped and defines an access opening 3 . The access opening 3 can be closed by an access door 4 .
FIG. 2 shows the apparatus of FIG. 1 after the centering device 2 has been removed and the access door 4 has been opened. FIG. 2 particularly shows a hinge bolt 5 of the access door 4 which is guided in projections 6 of the access door 4 , wherein the projections 6 are provided with guide recesses 7 . In the closed state of the access door 4 , the projections 6 of the access door 4 mesh in the manner of a comb in projections 8 of the outer frame 1 . The projections 8 also have guide recesses 9 .
For carrying out a closing procedure of the access door 4 , the hinge bolt 5 is pulled out of the guide recesses 7 of the projections 6 and, after the access door 4 has been closed, the hinge bolt 5 is pushed through all guide recesses 7 , 9 of the projections 6 , 8 .
When opening and closing the access door 4 , a second hinge bolt 5 advantageously remains in the area of the corresponding guide recesses 7 , 9 and forms a rotary hinge as a result.
FIG. 2 shows carriers 10 of a wedge device 11 . The wedge device 11 additionally has a positioning device 12 which supports the carriers 10 and is mounted so as to be movable relative to the outer frame 1 in a vertical direction.
FIG. 3 is a perspective view of the outer frame 1 with the access door 4 removed. Viewable as a result are projections 13 with guide recesses 14 for the hinge bolts 5 . In the closed state, the projections 13 of the access door 4 mesh with the projections 8 of the outer frame 1 .
FIG. 4 shows the access door 4 with pulled-out hinge bolts 5 . This makes visible projections 13 with guide recesses 14 for the hinge bolts 5 . In a closed state, the projections 13 of the access door 4 mesh with the projections 8 of the outer frame 2 .
FIG. 5 is a partial illustration on a significantly larger scale, showing in a top view an access door 4 which is arranged in the area of the access opening 3 . FIG. 5 shows the state of assembly before the projections 13 of the access door 4 have been engaged with the projections 8 of the outer frame 1 . It can particularly be seen that the guide recesses 9 , 14 have an essentially oval cross-section. As a result, the hinge bolts 5 , which have an essentially circular cross-section, can be inserted with play into the guide recesses 9 , 14 and a mechanical clamping action can be effected by an activation of the wedge device 11 which occurs by a vertical displacement of the positioning device 12 .
FIG. 6 shows the outer frame 1 with the access door 4 in place prior to carrying out clamping of the wedge device 11 which is not illustrated in the Figure. It can be seen that the hinge bolt 5 is mounted with play.
FIG. 7 shows the device of FIG. 6 after clamping has been performed. The hinge bolts 5 successively rest against the oppositely located limiting surfaces of the guide recess 9 , 14 .
FIG. 8 is a perspective view similar to FIG. 2 with the centering device 2 being mounted and open. In accordance with this embodiment, the centering device 2 is formed of two semicircular segments which can each be pivoted with the outer frame 1 . The access door 4 is shown opened and this makes it possible to see the positioning device 12 .
FIG. 9 is a partial illustration of the device of FIG. 8 shown after a partial disassembly of one of the carrier 10 supported by the positioning device 12 by using the tool 16 . The carrier 10 is pulled out in the vertical direction and upwardly out of the positioning device 12 by using the tool 16 .
FIG. 10 of the drawing shows an illustration of the outer frame 2 similar to FIG. 3 , however, with outer adapters 17 being disassembled. By using the outer adapters 17 it is possible to insert differently dimensioned outer frames 1 in uniformly dimensioned receiving devices which are installed in the area of drilling platforms.
FIG. 11 shows an embodiment which is modified compared to the embodiment of FIG. 10 , wherein the outer adapters 17 are not constructed in the manner of a block, as seen in FIG. 10 , but in the manner of circular segments. Advantageously, the outer adapters 17 shown in FIG. 10 as well as in FIG. 11 are fastened to the outer frame 1 by means of bolts 18 .
FIG. 12 is a side view of the device of FIG. 4 in a viewing direction toward the front of the access door 4 . This essentially illustrates the symmetric configuration of the total apparatus.
The top view of FIG. 13 shows the arrangement of three carriers 10 within the positioning device 12 . FIG. 14 shows a top view with the access door 4 being opened.
FIG. 15 shows another illustration of the outer frame 1 without the access door 4 being in place and with the use of an outer adapter ring. FIG. 16 once again illustrates in a top view the outer frame 1 with the access door 4 being closed and three carriers 10 being used. Each of the carriers 10 supports a plurality of wedges 19 which serve for securing a pipe 20 .
FIG. 17 is an exploded view of a carrier 10 with its corresponding wedges 19 and support elements 21 . The wedges 19 are placed in indentations 22 of the carrier 10 and are secured by the support elements 21 . In the illustrated embodiment, always two wedges 19 are arranged in pairs one above the other. In addition, a row of wedges 19 are arranged next to each other. This results in two rows of wedges 19 which are arranged one above the other and are separated from each other by a support element 21 . Additional support elements 21 are arranged in the area of ends of the ridges 19 which are facing away from each other and which serve for further securing the wedges 19 at the carrier 10 .
FIG. 18 shows the device of FIG. 17 after the components have been assembled. The support elements 21 are secured with the use of bolts 23 at the carrier 10 .
FIG. 19 is an exploded view of the total apparatus in order to illustrate the geometric arrangement of the individual components relative to each other.
FIG. 20 shows an embodiment in which the outer frame 1 is formed of two frame segments of essentially the same size which may be connected to each other, for example, by screws. The frame segments 24 , 25 contact each other in the area of a plane 26 of separation. This embodiment avoids the use of a separate access door 4 . Four holding wedges are being used.
FIG. 21 is a perspective view of the apparatus of FIG. 20 .
The perspective view of FIG. 22 shows another embodiment which uses two frame segments 24 , 25 . In this case, the frame segments 24 , 25 are connected to each other essentially in accordance with the connecting principle according to FIG. 1 . The frame segments 24 , 25 have projections 27 which are provided with guide recesses 28 for locking bolts, not shown.
While specific embodiments of the invention have been shown and described in detail to illustrate the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles. | An apparatus for vertically supporting pipes in oil production rigs. The apparatus includes an outer frame and a centering device. In the area of an inner side of the outer frame, at least one wedge device is provided for clamping the pipe. The outer frame is connected to the centering device so as to be vertically aligned and facing upwardly. A wedge device may additionally include a positioning device and a carrier provided with at least one wedge. | 4 |
This application is a divisional application of Applicants' copending parent application Ser. No. 318,448, filed Dec. 26, 1972.
BACKGROUND OF THE INVENTION
This invention relates to novel flame retardant compounds, flame retardant resin compositions containing same and to a method for imparting flame resistance to natural and synthetic resins.
More particularly, this invention is directed to novel haloalkyl esters of glycols which have been found to impart flame resistance to a variety of polymeric materials.
Prior Art
Prior art which appears relevant to the present invention is as follows:
U.S. Pat. No. 2,978,478 discloses that alkylene glycols may be reacted with phosphorus compounds, such as phosphorus-oxychloride, to prepare phosphate esters. The reaction described in the patent is disclosed in the present invention as a method for preparing intermediate compounds which are subsequently converted to the novel flame retardant compounds of the present invention. The patent advises against preparing phosphate esters by the glycol/phosphorus oxychloride reaction since it is stated that heterocyclic esters will result therefrom, as well as the formation of diphosphate and polyphosphate esters. The patent does not disclose the compounds of the present invention.
U.S. Pat. No. 3,192,242 discloses certain bis (halo-methyl)-1,3- propylenebis (phosphoroidihalidates) and reaction thereof with oxirane compounds to prepare flame retardant halogenated diphosphates. The haloalkyl glycol esters of the present invention are not shown.
U.S. Pat. No. 3,360,591 discloses chlorine-substituted aromatic esters of aromatic glycols which are used to reduce preignition of fuels. The compounds of the present invention are not disclosed.
Summary of the Invention
This invention relates to compounds of the formula ##STR1## WHEREIN R represents alkylene, cycloalkylene or bis (alkylene) cycloalkylene; R' represents an alkylene group of 1 to 10 carbon atoms; X represents oxygen or sulfur; hal represents chlorine or bromine and n represents 1 when R is alkylene and a integer of from 0 to 5 when R represents cycloalkylene or alkylene-cycloalkylene. The compounds of the invention have utility as flame retardant materials for resins.
The objective of this invention is to provide novel flame retardant materials to provide resin compositions containing same and to also provide a method for imparting flame retardance to resin systems.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The objective of this invention is accomplished by providing compounds of formula (I) above.
The novel compounds of the invention are prepared by reacting phosphoroldihalidates of glycols or glycol ethers having the formula
HO-R (OR).sub.n OH II
wherein R and n are defined above with respect to Formula (I), with an oxirane compound.
Illustrative glycols which are utilized in the preparation of the compounds of the invention include alkylene glycols, cycloalalkylene glycols, bis (alkylene) cycloalkylene glycols and alkylene glycol ethers. Illustrative alkylene glycols include alkylene glycols having from 1 to 10 carbon atoms, such as ethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, and decamethylene glycol.
Illustrative cycloalkylene glycols include cyclohexylene glycol (e.g. 1.4-cyclohexanediol) and cyclopentylene glycol and similar compounds.
Illustrative bis (alkylene) cycloalkylene glycols include bis (methylene) cyclohexylene glycol (e.g. 1.4-cyclohexane dimethylol), bis (ethylene) cyclohexylene glycol, bis (propylene) cyclohexylene glycol and like compounds.
Illustrative glycol ethers include diethylene glycol, dipropylene glycol and the like.
The preferred glycols and glycol ethers which are utilized to prepare the flame retardant materials of the present invention include diethylene glycol, ethylene glycol, cyclohexane dimethylol and cyclohexanediol.
The oxirane reactant which is utilized in the preparation of the compounds of the present invention include diethylene glycol, ethylene glycol, cyclohexane dimethylol and cyclohexane diol.
The oxirane reactant which is utilized in the preparation of the compounds of the present invention includes ethylene oxide, 1,2-propylene oxide, mixtures of ethylene oxide and propylene oxide, styrene oxide, epoxyalkanes such as 1,2-epoxybutane and the like.
The phosphorus oxyhalide or thiohalide reactant which is utilized in the preparation of the compounds of the present invention includes phosphorus oxytrichloride, phosphorus oxytribromide, phosphorus oxydibromidechloride and the corresponding thiophosphorus analogs.
Generally, the compounds of the invention are prepared by initially reacting the desired glycol with a phosphorus oxyhalide or phosphorus thiohalide to afford the intermediate glycol phosphorodihalidate or thiophosphorodihalidate, which is subsequently reacted with a oxirane compound to obtain the compounds of the invention.
The reaction conditions under which the compounds of the present invention are prepared are applicable to either batch or continuous operation. The temperature may be in the range of 0° to 100°C., with 40° to 60°C. preferable. Although the reaction may be run under a vacuum, a slight pressure (i.e. 2-20 psi) is preferable. Standard purification work-up procedures are used.
Fire retardant properties are afforded in natural and synthetic polymer materials by incorporating the compounds of the invention into such materials in an amount of from 1 to 100 phr (parts per hundred resin), preferably in an amount of from about 3 to about 20 phr.
The following examples illustrate specific embodiments of the preparation and utility of certain of the compounds of the present invention.
EXAMPLE 1
Preparation of diethylene glycol bis-phosphorodichloridate
In a 1 liter flask, fitted with a mechanical stirrer, thermometer and reflux condenser are placed 307 gms. (2.0 moles) phosphorus oxychloride. The phosphorus oxychloride is cooled to 14° to 15°C. and 106 gms. (1.0 moles) of diethylene glycol is added over a period of 2 to 3 hours. Residual phosphorus oxychloride is removed. The product recovered is is diethylene glycol bis-phosphorodichloridate. The temperature of the reaction mixture is then raised to 30°C. for about 1 hour.
EXAMPLE 2
Preparation of diethylene glycol bis-di-2-chloroethylphosphate
To the product of Example 1 there is added 2.5 gms. tetrabutyl titanate. Ethylene oxide is added subsurface at such a rate that the temperature is maintained at 65°-70°C. Completion of the reaction is indicated by the abrupt drop in temperature. The product is washed with sodium bicarbonate/water, dehydrated and filtered. The product is diethylene glycol bis-di-2-chloroethylphosphate. There is obtained 507 gms. (98 percent) of product.
EXAMPLE 3
Preparation of cyclohexane dimethylol-1,4-bis-phosphorodichloridate
In accordance with the procedure of Example 1, there are reacted one mole of cyclohexane dimethanol and two moles phosphorusoxychloride. The product is cyclohexane dimethylol-bis-phosphorodichloridate.
EXAMPLE 4
Preparation of cyclohexane dimethylol-bis-di-2-chloroethylphosphate
In accordance with the procedure of Example 2, tetrabutyl titanate is added to the product of Example 3 and ethylene oxide is introduced. The product is cyclohexane dimethylol-bis-di-2-chloroethylphosphate.
Following the procedure of Examples 1-4, but substituting phosphorus thiochloride for phosphorus oxychloride there is obtained diethylene glycol bis-thiophosphorodichloridate, diethylene glycol bis-di-2-chloroethylthiophosphate, cyclohexane dimethylol bis-thiophosphorodichloridate and cyclohexane dimethylol bis-di-2-chloroethylthiophosphate.
Substitution of propylene oxide for ethylene oxide in Examples 2 and 4 affords diethylene glycol bis-di-2-chloropropylphosphate and cyclohexanedimethylol bis-di-2-chloropropylphosphate.
EXAMPLE 5
Preparation of cyclohexanediol bis-phosphorodichloridate
In accordance with the procedure of Example 1, there are reacted one mole of 1,4-cyclohexanediol and two moles of phosphorus oxychloride to afford cyclohexanediol bis-phosphorodichloridate.
EXAMPLE 6
Preparation of cyclohexanediol-1,4-bis-di-2-chloroethylphosphate
In accordance with the procedure of Example 2, tetrabutyl titanate is added to the product of Example 5 and ethylene oxide is introduced. The product is cyclohexanediol-1,4-bis-di-2-chloroethylphosphate.
EXAMPLE 7
This example illustrates the flame retardant utility of the compounds of the present invention when incorporated in various resin composition.
A polymer composition is prepared having the following formulation:
Substituent Parts by Weight______________________________________"EPI-REZ".sup.1 70.0"VERSAMID".sup.2 30.0"MODAFLOW".sup.3 0.3Flame Retardant 5, 10 or 20______________________________________.sup.1 "EPI-REZ" 510 -- epoxy resin presently available from Celanese Chemical Co..sup.2 "VERSAMID" -- polyamide stabilizer presently avail- able from General Mills..sup.3 "MODAFLOW" -- processing aid presently available from Monsanto Company.
Three formulations are prepared, one being a control, the second containing a commercial flame retardant ("FYROL" 99, a trademark of Stauffer Chemical Co. for their brand of ethylene glycol polyphosphate flame retardant) and the third containing the compound of Example 2 of the invention. The comparative properties of the resins are shown in Table I, below. The "oxygen index" reflects data obtained in accordance with ASTM D2863-70 and is defined as the minimum concentration of oxygen, expressed as volume percent, in a mixture of oxygen and nitrogen that will just support combustion under the conditions of the test procedure. The greater the oxygen index, the better the flame retardancy.
Table I__________________________________________________________________________ Water Extraction Oxygen 48 Hrs. Drying Volatility, Index, % Soluble &Flame Retardant PHR* % Loss % O.sub.2 Mat. LOss Absorption__________________________________________________________________________Control 0 0.11 17.9 0 1.89Ethyleneglycol polyphosphate 5 0.59 21.2 0 3.22 10 0.03 21.2 0.05 3.96Example 2 5 0.46 21.6 0 3.04Compound** 10 0.03 21.3 0.56 4.12__________________________________________________________________________ * PHR--parts per hundred resin ** Diethylene glycol bis-di-2-chloroethyl phosphate
The compound of Example 2 demonstrates improved flame retardance.
EXAMPLE 8
The compound of Example 2 is formulated, at 15 phr, into a flexible urethane foam having the following formulation:
Substituent Parts by Weight______________________________________Polyoxypropylene glycol 100.00Triethylenediamine 0.65Silicon surfactant 1.00Water 4.00Stannous octoate stabilizer 0.16Tolylene diisocyanate 54.00______________________________________
The properties of the formulation are tested in comparison to a control containing no flame retardant and in comparison to the formulation containing 15 phr of a commercial flame retardant. The data are shown in Table II, below.
The column marked "ASTM-D-1962" in Table II refers to a horizontal burning test for cellular plastics. In such test, a specimen (6 inches × 2 inches × 1/2 inch) is supported on a horizontal, hard-cloth support with the 1/2 inch dimension vertical. One end of the specimen is contacted for 60 seconds with a 11/2 inch high blue flame from a 3/8 inch diameter barrel Bunsen Burner fitted with a 17/8 inch wide wingtop.
If the specimen instantly goes out, it is self-extinguishing. If the specimen burns and subsequently goes out, it is characterized as self-extinguishing/burn rate given as inches and seconds burned. If the specimen completely burns, its burn rate in inches/minute is given.
Table II______________________________________Flame Rate Self-Exting. VolatilityRetardant In./Min. In. Sec. Fogging % Loss______________________________________Control 6.8 -- -- 99 0.20Example 2Compound -- 0.5 10 89 0.77Ethyleneglycolpolyphosphate -- 0.5 11 44 1.43______________________________________
Fire retardants incorporated in flexible urethane foam are often so volatile as to be unusable in practical applications. In Table II the compound of Example 2 renders the foam self-extinguishing with only a slight increase in volatility. It also processes with no internal discoloration or scorch. Ethylene glycol polyphosphate has been found to scorch in this formulation and, while rated self-extinguishing, is twice as volatile as the compound of Example 2.
Results comparable to Examples 7 and 8 are obtained when the compounds of the present invention are incorporated in other resin systems, e.g. methacrylates, melamine/formaldehyde, vinyl halides and the like as described hereinafter.
As illustrated in Example 7 and 8, the compounds of the present invention are useful as flame retardants for a wide variety of natural and synthetic polymer materials. The compounds may be used in concentrations of from about 0.1 percent by weight of polymer up to about 50 weight percent or more depending on the particular use for which the polymer material is intended.
Synthetic polymer materials, i.e., those high molecular weight organic materials which are not found in nature, with which the compounds of the invention are advantageously employed may be either linear or crosslinked polymers and may be in the form of sheets, coatings, foams and the like. They may be either those which are produced by addition or condensation polymerization.
An important class of polymers which are beneficially flame retarded with the compounds of the invention are those obtained from a polymerizable monomer compound having ethylenic unsaturation. A particularly preferred class of polymers which are flame retarded consist of the polymerized vinyl and vinylidene compounds, i.e., those having the CH 2 = C< radical. Compounds having such a radical are, for example, the solid polymeric alkenes, such as polyethylene, polypropylene, polyisobutylene or ethylene/propylene copolymers; polymerized acrylyl and alkacrylyl compounds such as acrylic, fluoroacrylic and methacrylic acids, anhydrides, esters, nitriles and amides, for example, acrylonitrile, ethyl or butyl acrylate, methyl or ethyl methacrylate, methoxymethyl or 2-(2-butoxyethoxy)ethyl methacrylate, 2-(cyanoethoxy)ethyl 3-(3-cyanopropoxy)propyl acrylate or methacrylate, 2-(diethylamino) ethyl or 2-chloroethyl acrylate or methacrylate, acrylic anhydride or methacrylic anhydride; methacrylamide or chloroacrylamide; ethyl or butyl chloracrylate; the olefinic aldehydes such as acrolein, methacrolein and their acetals; the vinyl and vinylidene halides such as vinyl chloride, vinyl fluoride, vinylidene fluoride and 1-chloro-1-fluoroethylene; polyvinyl alcohol; the vinyl carboxylates such as vinyl acetate, vinyl chloroacetate, vinyl propionate, and vinyl 2-ethylhexanoate; the N-vinyl imides such as N-vinyl phthalimide and N-vinyl succinamide; the N-vinyl lactams such as N-vinyl caprolactam and N-vinyl butyrolactam; vinyl aromatic hydrocarbon compounds such as styrene, alpha-methylstyrene, 2,4-dichlorostyrene, alpha- or beta-vinyl-naphthalene, divinyl benzene and vinyl fluorene; the vinyl ethers such as ethyl vinyl ether or isobutyl vinyl ether; vinyl-substituted heterocyclic compounds such as vinyl pyridine, vinyl pyrrolidone, vinylfuran or vinylthiophene; the vinyl or vinylidene ketones such as methyl vinyl ketone or isopropenyl ethyl ketone; vinylidene cyanide. Homopolymers of the above compounds or copolymers and terpolymers thereof are beneficially flame retarded by the compounds of the present invention. Examples of such copolymers or terpolymers are those obtained by polymerization of the following monomer mixtures; vinyl chloride/vinyl acetate, ethylene/vinyl chloride/vinyl acetate, acrylonitrile/vinyl pyridine, styrene/methyl methacrylate, styrene/N-vinyl pyrrolidone, cyclohexyl methacrylate/vinyl chloroacetate, acrylonitrile/vinylidene cyanide, methyl methacrylate/vinyl acetate, ethyl acrylate/methacrylamide/ethyl chloroacrylate, vinyl chloride/vinylidene chloride/vinyl acetate.
Other polymers of compounds having the ethylenic group, >C = C<, are homopolymers, copolymers and terpolymers of the alpha-, beta-olefinic dicarboxylic acids and derivatives thereof such as the ahydrides, esters, amides, nitriles and imides for example, methyl, butyl, 2-ethylhexyl or dodecyl fumarate or maleate; maleic chloromaleic, citraconic or itaconic anhydride; fumaronitrile, dichlorofumaronitrile or citracononitrile; fumaramide, maleamide or N-phenyl maleamide. Examples of particularly useful polymers and terpolymers prepared from the alpha-, beta- olefinic dicarboxylic compounds are the copolymers of maleic anhydride and a vinyl compound such as ethylene, propylene, isobutylene, styrene, alpha methylstyrene, vinyl acetate, vinyl propionate, methyl isopropenyl ketone, isobutyl vinyl ether, the copolymers of dialkyl fumarate such as ethyl or butyl fumarate and vinyl compounds such as styrene, vinyl acetate, vinylidene chloride, ethyl methacrylate, acrylonitrile and the like.
The compounds of the invention act as flame retardants for the polymers and copolymers of unsaturated, cyclic esters of carbonic acid, for example, homopolymeric vinylene carbonate or the copolymers of vinylene carbonate with ethylenic compounds such as ethylene, vinyl chloride, vinyl acetate, 1,3-butadiene, acrylonitrile, methacrylonitrile, or the esters of methacrylic or acrylic acid.
Readily flame retarded by the compounds of the invention are also the polyarylcarbonate polymers such as the linear polyarylcarbonates formed from diphenols or dihydroxy aromatic compounds including single and fused-ring nucleii with two hydroxy groups as well as monohydroxy-substituted aromatic residues jointly in pairs by various connecting linkages. Examples of the foregoing include dihydorxy benzenes, naphthalenes and the like, the dihydroxydiphenyl ethers, sulfones, alkanes, ketones and the like.
The compounds of the invention also act as flame retardants for polymers, copolymers or terpolymers of polymerizable compounds having a plurality of double bonds, for example, rubbery, conjugated diene polymerizates such as homopolymerized 3-butadiene, 2-chlorobutadiene or isoprene and linear copolymers or terpolymers such as butadiene/acrylonitrile, isobutylene/butadiene, butadiene/styrene; esters of saturated di- or poly-hydroxy compounds with olefinic carboxylic acids such as ethylene glycol dimethacrylate, triethylene glycol dicrotonate or glyceryl triacrylate; esters of olefinic alcohols with dicarboxylic acids or with olefinic monocarboxylic acids such as diallyl adipate, divinyl succinate, diallyl fumarate, allyl methacrylate or crotyl acrylate and other diethylenically unsaturated compounds such as diallyl carbonate, divinyl ether or divinylbenzene, as well as the crosslinked polymeric materials such as methyl methacrylate/diallyl methacrylate copolymer or butadiene/styrene/divinyl benzene terpolymer.
The cellulose derivatives are flame retarded by the compounds of the present invention. For example, cellulose esters such as cellulose acetate, cellulose triacetate or cellulose butyrate, the cellulose ethers such as methyl or ethyl cellulose, cellulose nitrate, carboxymethyl cellulose, cellophane, rayon, regenerated rayon and the like may be flame retarded.
The compounds of the present invention are well suited for flame retarding liquid resin compositions of the polyester type, for example, the linear polyesters which are obtained by the reaction of one or more polyhydric alcohols with one or more alpha, beta-unsaturated polycarboxylic acids alone or in combination with one or more saturated polycarboxylic acid compounds, or the crosslinked polyester resins which are obtained by reacting a linear polyester with a compound containing a CH 2 = C< group.
The compounds of the present invention are compatible flame retardants for epoxy resins. Such resins are condensation products formed by the reaction of a polyhydroxy compound and epichlorohydrin, which condensation products are subsequently cured by the addition of crosslinking agents. The hydroxy compounds may be, for example, ethylene glycol, 4,4'-isopropylidenediphenol and similar materials. The crosslinking agent employed in the curing step may be a dicarboxylic compound such as phthalic anhydride or adipic acid, but is more generally a polyamine such as ethylene diamine, paraphenylamine diamine or diethylene triamine.
Polyurethanes are a class of polymer materials which are flame retarded by the compounds of the present invention. The polyurethanes, like the above-mentioned polyesters, are materials which are employed in structural applications, for example, as insulating foams, in the manufacture of textile fibers, as resin bases in the manufacture of curable coating compositions and as impregnating adhesives in the fabrication of laminates of wood and other fibrous materials. Essentially, the polyurethanes are condensation products of a diisocyanate and a compound having a molecular weight of at least 500 and preferably about 1500-5000 and at least two reactive hydrogen ions. The useful active-hydrogen containing compounds may be polyesters prepared from polycarboxylic acids and polyhydric alcohols, polyhydric polyalkylene ethers having at least two hydroxy groups, polythioether glycols, polyesteramides and similar materials.
The polyesters or polyester amides used for the production of the polyurethane may be branched and/or linear, for example, the esters of adipic, sebasic, 6-aminocaproic, phthalic, isophthalic, terephthalic, oxalic, malonic, succinic, maleic, cyclohexane-1,2-dicarboxylic, cyclohexane-1,4-dicarboxylic, polyacrylic, naphthalene-1,2-dicarboxylic, fumaric or itaconic acids with polyalcohols such as ethylene glycol, diethylene glycol, pentaglycol, glycerol, sorbitol, triethanolamine and/or amino alcohols such as ethanolamine, 3-aminopropanol, and with mixtures of the above polyalcohols and amines.
The alkylene glycols and polyoxyalkylene or polythioalkylene glycols used in the production of polyurethanes may be ethylene glycol, propylene glycol, butylene glycol, diethylene glycol, triethylene glycol, polythioethylene glycol, dipropylene glycol and the like.
Generally, any of the polyesters, polyisocyanate-modified polyesters, polyester amides, polyisocyanate-modified polyester-amines, alkylene glycols, polyisocyanate-modified alkylene glycols, polyoxyalkylene glycols and polyisocyanate-modified polyoxyalkylene glycols having three reactive hydrogen atoms, three reactive carboxylic and/or especially hydroxyl groups may be employed in the production of polyurethanes. Moreover, any organic compound containing at least two radicals selected from the group consisting of hydroxy and carboxy groups may be employed.
The organic polyisocyanates useful for the production of polyurethanes include ethylene diisocyanate, ethylidene diisocyanate, propylene-1,2-diisocyanate, m-phenylene diisocyanate, 2,4-tolylene diisocyanate, triphenylmethane triisocyanate, or polyisocyanates in blocked or inactive form such as the bis-phenyl carbamates of tolylene diisocyanate and the like.
Phenolic resins are flame retarded by the compounds of the present invention, which compounds may be incorporated into the phenolic resin either by milling and molding applications or by addition to film-forming or impregnating and bonding solutions prior to casting. Phenolic resins with which the present compounds are employed are, for example, the phenol-aldehyde resins prepared from phenols such as phenol, cresol, xylenol, resorcinol, 4-butylphenol, cumylphenol, 4-phenylphenol, -nonylphenol, and aldehydes such as formaldehyde, acetaldehyde or butyraldehyde in the presence of either acetic or basic catalysts, depending upon whether the resin is intended for use as a molding or extruding resin or as the resin base in coating and impregnating compositions.
Aminoplasts are another group of aldehyde resins which are flame retarded by the compounds of the invention. Examples of aminoplasts are the heat-convertible condensation products of an aldlehyde with urea, thiourea, quanidine, cyanamide, dicyandiamide, alkyl or aryl guanamines and the triazines such as melamine, 2-fluoro-4,6-diamino-1,3,5-triazine and the like. When the aminoplasts are to be used as impregnating agents, bonding adhesives, coatings and in casting of films, the compounds of the present invention are incorporated into solutions or suspensions in which the aminoplast is carried. The resulting mixtures give strong, fire-retardant laminates when sheets of paper, glass, cloth or fabric are impregnated therewith and cured.
Another class of compounds which are flame retarded by compounds of the present invention are the nylons, for example, the superpolyamides which are generally obtained by the condensation of a diamine, for example, hexamethylene diamine with a dicarboxylic acid, for example, adipic acid.
Other polyamides which are flame retarded in accordance with the present invention are the polypeptides which may be prepared, for example, by reaction of N-carbobenzyl oxyglycine with glycine or mixture of glycine and lysine or an N-carboxy amino acid anhydride such as N-carboxy-DL-phenylalanine anhydride, piperidone, 2-oxohexamethyleneimine and other cyclic amides. The compounds of the present invention can be incorporated into molding or extruding compositions for a flame retardant effect.
The compounds of the present invention are also useful as flame retardants for linear polymers obtained by the self-condensation of bifunctional compounds, for example, the polyethers which are derived by the self-condensation of dihydric alcohols such as ethylene glycol, propylene glycol or hexamethylene glycol; the polyesters which are obtained by the self-condensation of hydroxy acids such as lactic acid or 4-hydroxybutric acid; the polyamides which are prepared by the self-condensation of aminocarboxylic acids such as 4-aminobutyric acid; the polyahydrides which are formed by the self-condensation of dicarboxylic acids such as sebasic or adipic acid.
The preferred synthetic polymer materials which are flame retarded by the compounds of the present invention are the vinyl halide polymers in the form of milled products, plastisols and foams, rigid and flexible polyurethane coatings and foams, epoxy resins, ABS and GRS rubbers, aminoplasts and phenolics. The vinyl halide polymers can be simple, mixed homopolymers of vinyl chloride or polyvinylidene chloride, or copolymers or terpolymers in which the essential polymeric structure of polyvinyl chloride is interspersed at intervals with residues of other ethylenically unsaturated compounds copolymerizable therewith. The essential properties of the polymeric structure of polyvinyl chloride is retained if not more than about 40 percent of a comonomer is copolymerized therewith. Especially preferred copolymers include ethylene/vinyl chloride and vinyl chloride/acrylonitrile copolymers. Especially preferred terpolymers include ethylene/vinyl chloride/acrylonitrile, ethylene/vinyl chloride/acrylic acid and ethylene/vinyl chloride/acrylamide terpolymers.
Natural polymeric materials which may be flame retarded by the compounds of the present invention include natural rubber, cellulose esters, for example, cellulose acetate and cellulose nitrate, ethyl cellulose, cork and wood flour products and similar cellulosic materials.
The polymer formulations which are flame retarded in accordance with the present invention, whether in sheet or film form or of foam or molded structure, may contain various conventional additives such as fillers, extenders, crosslinking agents and colorants. Minor amounts of stabilizers, for example, are usually incorporated to reduce the effects of heat and light.
When foamable compositions are used, the composition may be a self-blowing polymer or the polymer may be blown by chemical or mechanical means or by the use of compressed gas. Fillers which are frequently employed to lower the cost of the finished material and to modify its properties include calcium carbonate and magnesium silicate. When fillers are employed, they are generally present in an amount of up to about 150 parts by weight of filler per 100 parts by weight of polymer formulation.
Where a colored or tinted composition is desired, colorants or color-pigments are incorporated in amounts of from about one to about five parts by weight to 100 parts by weight of polymer.
Surfactants such as silicones are normally added to foam formulations which are mechanically frothed. The surfactants reduce the surface tension of the foam and thereby increase the air or gas entrapment characteristics of the foam.
Additionally, glass-forming inorganic materials such as zinc borate, zinc oxide, lead oxide, lead silicate and silicon dioxide may be added to decrease the flame and smoke generating characteristics of the polymer.
While the invention has been described by referring to certain specific embodiments, it is not so limited since many modifications and variations are possible in the light of the above teachings. The invention may therefore be practiced otherwise than as specifically described without departing from the spirit and scope of the invention. | Compound of the formula ##EQU1## WHEREIN R represents alkylene, cycloalkylene or alkylenecycloalkylene, R' represents an alkylene group of 1 to 10 carbons, X represents oxygen or sulfur, hal represents chlorine or bromine and n represents an integer from 0 to 5, are useful as flame retardants for material and synthetic material. | 8 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a radiation image recording and read-out apparatus for recording a radiation image on a stimulable phosphor, exposing the stimulable phosphor to stimulating rays which cause the stimulable phosphor to emit light in proportion to the stored radiation energy, detecting the emitted light to read out the radiation image, and converting the emitted light into electric signals. This invention particularly relates to a radiation image recording and read-out apparatus which efficiently carries out image recording, image read-out and other processing.
2. Description of the Prior Art
When certain kinds of phosphors are exposed to a radiation such as X-rays, α-rays β-rays, γ-rays, cathode rays or ultraviolet rays, they store a part of the energy of the radiation. Then, when the phosphor which has been exposed to the radiation is exposed to stimulating rays such as visible light, light is emitted by the phosphor in proportion to the stored energy of the radiation. A phosphor exhibiting such properties is referred to as a stimulable phosphor.
As disclosed in U.S. Pat. No. 4,258,264 and Japanese Unexamined Patent Publication No. 56(1981)-11395, it has been proposed to use a stimulable phosphor in a radiation image recording and reproducing system. Specifically, a recording material provided with a layer of the stimulable phosphor is first exposed to a radiation passing through an object such as the human body to have a radiation image of the object stored thereon, and is then two-dimensionally scanned by stimulating rays such as a laser beam which cause the recording material to emit light in proportion to the stored radiation energy. The light emitted by the recording material upon stimulation thereof is photoelectrically detected and converted to electric image signals by a photodetector, and the radiation image of the object is reproduced as a visible image by use of the image signals on a recording medium such as a photographic film, a display device such as a cathode ray tube (CRT), or the like.
The radiation image recording and reproducing system using a recording material provided with a stimulable phosphor is advantageous over conventional radiography using a silver halide photographic material in that the image can be recorded over a very wide range (latitude) of radiation exposure. More specifically, since the amount of light emitted upon stimulation after the radiation energy is stored on the stimulable phosphor varies over a wide range is proportion to the amount of said stored energy, it is possible to obtain an image having desirable density regardless of the amount of exposure of the recording material provided with the stimulable phosphor to the radiation, by reading out the emitted light with an appropriate read-out gain and converting it into electric signals to reproduce a visible image on a recording medium or a display device.
In the aforesaid radiation image recording and reproducing system, the recording material provided with the stimulable phosphor is used to temporarily store the radiation image in order to reproduce the final visible image therefrom on a final recording medium. For economical reasons, therefore, it is desirable that the recording material provided with the stimulable phosphor be used repeatedly.
Accordingly, the applicant proposed in, for example, Japanese Unexamined Patent Publication No. 58(1983)-200269, a radiation image recording and read-out apparatus which enables efficient circulation and reuse of the stimulable phosphor.
The proposed radiation image recording and read-out apparatus comprises, built in a single apparatus:
(a) a supporting material,
(b) at least one recording material fixed on said supporting material and comprised of a stimulable phosphor layer capable of storing a radiation image,
(c) an image recording section for exposing said recording material to a radiation passing through an object to have a radiation image of the object stored on said recording material,
(d) an image read-out section provided with a stimulating ray irradiation means for irradiating stimulating rays to said recording material carrying said radiation image stored thereon, and a photoelectric read-out means for obtaining electric image signals by reading out light emitted by said recording material in proportion to the stored radiation energy when said recording material is exposed to the stimulating rays,
(e) a means for circulating said recording material on said supporting material with respect to said image read-out section for enabling reuse of said recording material by repeatedly moving said supporting material and said image read-out section with respect to each other, and
(f) an erasing section for eliminating the radiation energy remaining on said recording material prior to image recording on said recording material after the radiation image is read out therefrom at said image read-out section,
whereby the recording material is efficiently circulated and reused.
In the proposed radiation image recording and read-out apparatus, it is very advantageous that a material comprising an endless supporting belt and a plurality of stimulable phosphor layers overlaid on the endless supporting belt be used as the recording material. In this case, the recording material can be applied around rollers or the like and conveyed and circulated sequentially through the image recording section, the image read-out section and the erasing section. An example of such a configuration is shown in FIG. 5.
With reference to FIG. 5, three stimulable phosphor sheets 102, 102, 102 are fixed on an endless conveyor 101. The conveyor 101 is provided around rollers 103 and 104, and moved in the direction as indicated by the arrow by rotations of the rollers 103 and 104. Around the conveyor 101, an image recording section 110, an image read-out section 120 and an erasing section 130 are disposed sequentially in the direction of conveyance by the conveyor 101.
The image recording section 110 is provided with a radiation source 111 which may be an X-ray source or the like, and stores a radiation image of an object 112 on the stimulable phosphor sheet 102 facing the radiation source 111 via the object 112. The stimulable phosphor sheet 102 carrying the radiation image thus stored thereon is then sent to the image read-out section 120. The image read-out section 120 is provided with a stimulating ray source 121 for emitting stimulating rays 121A such as a laser beam, a light deflector 122 constituted by a galvanometer mirror or the like for deflecting the stimulating rays 121A emitted by the stimulating ray source 121 in the width direction of the conveyor 101, and a photodetector 123 for reading out the light 125 emitted by the stimulable phosphor sheet 102 upon stimulation thereof by the stimulating rays 121A. The photodetector 123 may be constituted by a head-on type photomultiplier, a photoelectric amplification channel plate or the like. The photodetector 123 photoelectrically detects the light 125 emitted by the stimulable phosphor sheet 102 upon stimulation thereof and guided by a light guide member 124. When the image-recorded stimulable phosphor sheet 102 has been sent to the image read-out section 120, the stimulable phosphor sheet 102 is moved normal to the direction of scanning of the stimulating rays 121A, so that the overall surface of the stimulable phosphor sheet 102 is exposed to the stimulating rays 121A and the image read-out is carried out over the overall surface of the stimulable phosphor sheet 102. After the image read-out from the stimulable phosphor sheet 102 is finished, the stimulable phosphor sheet 102 is sent to the erasing section 130 provided with an erasing light source 131. The erasing light source 131 irradiates light having a wavelength within the stimulation wavelength range of the stimulable phosphor sheet 102 onto the stimulable phosphor sheet 102 to cause it to release the radiation energy remaining thereon. The erasing light source 131 may be constituted by, e.g., a tungsten-filament lamp, a halogen lamp, an infrared lamp, or a laser source as disclosed in U.S. Pat. No. 4,400,619. The stimulable phosphor sheet 102 erased at the erasing section 130 is sent again to the image recording section 110. In the course of movement of the stimulable phosphor sheet 102 to the erasing section 130, the stimulable phosphor sheet 102 is cleaned by a cleaning roller 105, and dust is removed from the sheet surface.
However, with the radiation image recording and read-out apparatus as shown in FIG. 5 wherein the overall conveyor 101 is stopped or moved, various problems arise as described below. Specifically, the conveyor 101 must be stopped at the time the image recording is to be carried out at the image recording section 110, and must be moved at the time the image read-out is to be carried out at the image read-out section 120, so that the image recording and the image read-out cannot be carried out at the same time. Therefore, the image recording cannot be carried out as long as the image read-out from the stimulable phosphor sheet 102 is being carried out at the image read-out section 120. A comparatively long time is taken for the image read-out, and therefore the image recording cannot be carried out efficiently in the case where the image recording is to be carried out sequentially for may images. Also, with the radiation image recording and read-out apparatus as shown in FIG. 5, it is not always possible to carry out several image recording steps sequentially and to make wait the image-recorded stimulable phosphor sheets in the region prior to the image read-out section 120. Furthermore, as the conveyor 101 passes over the image read-out section 120 and the erasing section 130 at the same speed, the apparatus cannot satisfy the need that the erasing be carried out substantially by decreasing the speed of conveyance of the stimulable phosphor sheet at the time of the erasing as compared with the image read-out step.
SUMMARY OF THE INVENTION
The primary object of the present invention is to provide a radiation image recording and read-out apparatus wherein a stimulable phosphor layer is provided on an endless belt, and the conditions of conveyance of the endless belt at an image recording section, an image read-out section and other sections are adjustable independently.
Another object of the present invention is to provide a radiation image recording and read-out apparatus wherein processing is carried out substantially and efficiently at an image recording section, an image read-out section and other sections.
The present invention provides a radiation image recording and read-out apparatus comprising:
(i) an endless belt provided with a stimulable phosphor layer,
(ii) a conveyance means for conveying and circulating said endless belt applied around said conveyance means,
(iii) an image recording section provided to face said endless belt for exposing said stimulable phosphor layer to a radiation carrying an image to have the radiation image stored on said stimulable phosphor layer,
(iv) an image read-out section facing said endless belt and provided with a stimulating ray irradiation means for irradiating stimulating rays to said stimulable phosphor layer carrying said radiation image stored thereon, and a photoelectric read-out means for obtaining electric image signals by reading out light emitted by said stimulable phosphor layer in proportion to the stored radiation energy when said stimulable phosphor layer is exposed to the stimulating rays, and
(v) an erasing section provided to face said endless belt for eliminating the radiation energy remaining on said stimulable phosphor layer prior to image recording on said stimulable phosphor layer after the radiation image is read out therefrom at said image read-out section,
wherein said conveyance means is provided with adjustment sections capable of variably adjusting a length of conveyance of said endless belt, said adjustment sections being provided at least at two positions.
The stimulable phosphor layer may be formed over the overall surface of the endless belt, or only at necessary portions of the surface of the endless belt.
With the radiation image recording and read-out apparatus in accordance with the present invention wherein the adjustment sections are provided, various effects can be achieved in accordance with the positions of the adjustment sections. Specifically, in the case where the two adjustment sections are provided before and after the image recording section respectively, the image recording can be carried out by stopping the conveyance of the endless belt at the image recording section, and the read-out of an image stored on an endless belt portion can be carried out at the image read-out section by shortening the length of conveyance of the endless belt at the adjustment section provided before the image recording section and feeding the endless belt portion to the image read-out section. Also, the endless belt fed out of the image read-out section can be accommodated by increasing the length of conveyance of the endless belt at the adjustment section provided after the image recording section in accordance with the extent of shortening of the length of conveyance of the endless belt at the adjustment section provided before the image. recording section. In this manner, with the radiation image recording and read-out apparatus in accordance with the present invnetion, the image recording and the image read-out can be carried out simultaneously depending on the positions of the adjustment sections. Also, in the case where the adjustment section is provided before the image read-out section, the endless belt portions on which the image recording has been finished can be made to wait at this adjustment section.
Also, in the case where the adjustment sections are provided before and after the erasing section respectively, the speed of conveyance of the endless belt at the erasing section can be made lower than the speed of conveyance of the endless belt at the image read-out section by increasing the length of conveyance at the adjustment section provided before the erasing section as the endless belt is conveyed out of the image read-out section.
As mentioned above, with the radiation image recording and read-out apparatus in accordance with the present invention wherein the conveyance means for the endless belt is provided with at least two adjustment sections for changing the length of conveyance of the endless belt, the conditions of conveyance of the endless belt at the respective sections of the apparatus-can be changed. Therefore, the image recording and the image read-out can be carried out at the same time, or a plurality of the image recording steps can be carried out continuously. Also, the speed of conveyance of the endless belt can be changed between the image read-out and the erasing. Accordingly, with the radiation image recording and read-out apparatus in accordance with the present invention, processing at the respective sections of the apparatus can be carried out substantially and efficiently.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1A, 1B and 1C are side views showing an embodiment of the radiation image recording and read-out apparatus in accordance with the present invention,
FIGS. 2, 3 and 4 are schematic views showing further embodiments of the radiation image recording and read-out apparatus in accordance with the present invention, and
FIG. 5 is a schematic view showing the conventional radiation image recording and read-out apparatus,
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention will hereinbelow be described in further detail with reference to the accompanying drawings.
With reference in FIGS. 1A, 1B and 1C, a recording belt 1 composed of an endless belt on which a stimulable phosphor layer is formed over the overall surface is applied around conveying rollers 2A, 2B, 2C, 2D, 2E, 2F, 2G and 2H secured to predetermined positions and around tension rollers 3A, 3B, 3C, 3D, 3E, 3F, 3G and 3H as will be described later, and is conveyed and circulated in the direction as indicated by the arrow. In this embodiment, a conveyance means for the recording belt 1 is constituted by the conveying rollers 2A through 2H and the tension rollers 3A through 3H.
A radiation source 11 constituted by an X-ray source or the like is disposed above the recording belt 1 to face it. The upper region of the apparatus including the radiation source 11 and an image recording table 13 on which an object 12 is to be placed constitutes an image recording section 10. At the image recording section 10, the radiation source 11 is activated to produce a radiation, the radiation passes through the object 12 placed on the image recording table 13, and a radiation image of the object 12 is projected onto the recording belt 1. In this manner, the radiation image of the object 12 is stored on the stimulable phosphor layer of the recording belt 1. A plurality of radiation images can be stored on the recording belt 1, each radiation image is stored on each of the hatched portions of the recording belt 1 shown in FIG. 1. The portion of the recording belt 1 on which the image recording has been finished at the image recording section 10 is conveyed by the conveyance means to an image read-out section 20 provided below the recording belt 1.
The image read-out section 20 is provided with a stimulating ray irradiation means 24 for deflecting stimulating rays 22, which are produced by a laser beam source 21, by a light deflector 23 which may be a galvanometer mirror, and scanning the stimulating rays 22 in a main scanning direction normal to the drawing sheet in FIG. 1A, and a photoelectric read-out means 25 composed of a light guide member 26 and a photomultiplier 27 for photoelectrically detecting light emitted by the recording belt 1 in proportion to the stored radiation energy when the recording belt 1 is scanned by the stimulating rays 22. The photomultiplier 27 is a long photomultiplier as disclosed in Japanese Unexamined Patent Publication No. 62(1987)-16666 and provided so that a light receiving face of the long photomultiplier extends along the main scanning line at an angle normal to the drawing sheet in FIG. 1A. In FIG. 1A, reference numeral 28 denotes a reflection mirror for reflecting the light, which is emitted by the recording belt 1 in a direction opposite to the photomultiplier 27, toward the light guide member 26. At the image read-out section 20, the recording belt 1 is conveyed by the conveying rollers 2C, 2D, 2E and 2F at a predetermined speed rightwardly in FIG. 1A, i.e. in a sub-scanning direction, and the overall surface of the image-recorded portion of the recording belt 1 is two-dimensionally scanned by the stimulating rays 22 deflected approximately normal to the sub-scanning direction. As the recording belt 1 is scanned by the stimulating rays 22, the scanned portion of the recording belt 1 emits light in proportion to the stored radiation energy. The emitted light is detected by the long photomultiplier 27 via the light guide member 26, and electric image signals based on the emitted light are generated by the long photomultiplier 27.
The portion of the recording belt 1 for which the image read-out has been finished at the image read-out section 20 is conveyed by the conveying rollers 2C, 2D, 2E and 2F to an erasing section 30 provided adjacent to the image read-out section 20. The erasing section 30 comprises a case 31, and a plurality of (by way of example, three) erasing light sources 32, 32, . . . constituted by fluorescent lamps or the like and disposed in the case 31. The erasing light sources 32, 32, . . . mainly produce erasing light having a wavelength within the stimulation wavelength range of the stimulable phosphor layer of the recording belt 1. The erasing light is irradiated to the overall image forming region of the recording belt 1 while the recording belt 1 is being conveyed, thereby to release radiation energy remaining on the stimulable phosphor layer of the recording belt 1 after the image read-out is finished. The recording belt portion on which the erasing has been finished at the erasing section 30 is conveyed by the aforesaid conveying rollers to the image recording section 10 for reuse in image recording.
In this embodiment, a first adjustment section 40 for variably adjusting the length of conveyance of the recording belt 1 is constituted by the tension rollers 3A, 3B, 3C and 3D, and a second adjustment section 50 is constituted by the tension rollers 3E, 3F, 3G and 3H. The first adjustment section 40 and the second adjustment section 50 makes it possible to carry out the image recording and the image read-out simutaneously. Also, a part of the recording belt 1 for which the image recording has been finished can be made to wait before the image read-out section 20. The effects of the first adjustment section 40 and the second adjustment section 50 will be described hereinbelow.
The tension rollers 3A through 3H are urged by springs 4A through 4h respectively in directions that tension the recording belt 1, and are rotatable freely. By way of example, in the case where the image recording at the image recording section 10 and the image read-out at the image read-out section 20 are started simultaneously from the condition shown in FIG. 1A, the first adjustment section 40 adjusts to shorten the length of conveyance of the recording belt 1. Specifically, at the time the image recording is to be carried out at the image recording section 10, the conveying rollers 2A, 2B, 2G and 2H are stopped from rotating, hold the recording belt 1, and secure the belt portion between the conveying rollers 2A and 2B on one hand and the conveying rollers 2G and 2H on the other hand at the image recording position. On the other hand, the conveying rollers 2C, 2D, 2E and 2F are rotated in the directions as indicated by the arrows to move the recording belt 1 in the sub-scanning direction at the image read-out section 20. As shown in FIG. 1B, as the conveying rollers 2A, 2B, 2G and 2H are stopped from rotating and the conveying rollers 2C, 2D, 2E and 2F are rotated, the tension rollers 3A through 3D are gradually moved in directions that contract the springs 4A through 4D against the urging force of the springs 4A through 4D. As a result of the contraction of the springs 4A through 4D by the tension rollers 3A through 3D, the first adjustment section 40 feeds out the recording belt 1 toward the image read-out section 20. Therefore, the image read-out can be carried out at the image read-out section 20 while the image recording is being carried out at the image recording section 10. At this time, the portions of the recording belt 1 passing through the image read-out section 20 and the erasing section 30 are sequentially sent to the second adjustment section 50. As the conveying rollers 2G and 2H are stopped from rotating, the tension rollers 3E through 3H are moved by the urging force of the springs 4E through 4H in directions that increase the length of conveyance of the recording belt 1, and the recording belt 1 fed to the position prior to the image recording section 10 as a result of movement of the recording belt 1 at the image read-out section 20 is acccommodated by the second adjustment section 50.
On the other hand, a comparatively long time is taken for the image read-out at the image read-out section 20, and therefore it would be very efficient if the image recording could be carried out continuously while the read-out of a single image is being carried out at the image read-out section 20. With this embodiment wherein the first adjustment section 40 and the second adjustment section 50 are provided, the image recording can be carried out continuously. Specifically, in the case where the image recording is to be carried out continuously while the image read-out is being carried out, the conveying rollers 2C, 2D, 2E and 2F are rotated at speeds suitable for moving the recording belt 1 in the sub-scanning direction at a predetermined speed at the image read-out section 20, and the conveying rollers 2A, 2B, 2G and 2H are rotated at comparatively high speeds to feed the recording belt 1 by the length of a single-image portion to the image recording position each time a single image recording step is finished. Therefore, as shown in FIG. 1C, at the second adjustment section 50, the springs 4E through 4H are contracted to shorten the length of conveyance of the recording belt 1 by a difference between the rotation speeds of the conveying rollers 2E, 2F and the rotation speeds of the conveying rollers 2G, 2H. Also, at the first adjustment section 40, the tension rollers 3A through 3D are moved by the urging force of the springs 4A through 4D in directions that increase the length of conveyance of the recording belt 1 by a difference between the rotation speeds of the conveying rollers 2A, 2B and the rotation speeds of the conveying rollers 2C, 2D. In this manner, the portions of the recording belt 1 for which the image recording has been finished are sequentially made to wait at the first adjustment section 40, and the image read-out from these portions can be carried out sequentially at the image read-out section 20 after the image read-out from a preceding portion of the recording belt 1 is finished at the image read-out section 20.
As mentioned above, with this embodiment wherein the first adjustment section 40 and the second adjustment section 50 each composed of a group of the tension rollers are provided before and after the image recording section 10 respectively, the image recording and the image read-out can be carried out simultaneously, and it is possible to eliminate the problem that the next image recording cannot be carried out until the image read-out is finished. Also, with this embodiment wherein the first adjustment section 40 is utilized as the waiting zone, a plurality of the image recording steps can be carried out while the read-out of a single image is being carried out, and can thus be carried out efficiently. Furthermore, the waiting zone can be utilized regardless of the size of the recorded image, and the number of the image-recorded portions of the recording belt 1 that can be made to wait at the waiting zone can be increased in the case of the recording of small images.
The positions of provision and the configurations of the image recording section 10, the image read-out section 20, the erasing section 30, the first adjustment section 40 and the second adjustment section 50 may be changed in various manners. For example, as shown in FIG. 2, the tension rollers of the first adjustment section 40 and the second adjustment section 50 may be provided for horizontal movement. Also, as shown in FIG. 3, the image recording section 10 may be provided in horizontal relation to the apparatus, and the image read-out section 20 and the erasing section 30 may be provided one above the other.
The adjustment sections in the present invention need not necessarily be provided before and after the image recording section, and may be provided at different positions in accordance with the purposes. For example, as shown in FIG. 4, the adjustment sections may be provided before and after the erasing section 30.
In the embodiment shown in FIG. 4, at the time the image recording is to be carried out at the image recording section 10, the overall recording belt 1 is stopped. After the image recording is finished, conveying rollers 2I, 2J, 2K and 2L are rotated to move the recording belt 1 in the sub-scanning direction at the image read-out section 20. On the other hand, at the erasing section 30, in order to carry out the erasing substantially, it is necessary for the recording belt 1 to be moved at a speed lower than the movement speed at the image read-out section 20. Therefore, conveying rollers 2M and 2N provided before and after the erasing section 30 respectively are rotated at speeds lower than the rotation speeds of the conveying rollers 2I through 2L. In the case where a first adjustment section 140 and a second adjustment section 150 having the same configurations as the first adjustment section 40 and the second adjustment section 50 in the embodiment shown in FIG. 1A are provided before and after the erasing section 30 respectively, even though the movement speed of the recording belt 1 is different between the image read-out section 20 and the erasing section 30, the difference in the movement speed can be accommodated by increasing the length of conveyance at the first adjustment section 140 as indicated by the broken lines in FIG. 4, and shortening the length of conveyance at the second adjustment section 150.
The adjustment sections should preferably be provided at three positions, i.e. between the image recording section 10 and the image read-out section 20, between the image read-out section 20 and the erasing section 30, and between the erasing section 30 and the image recording section 10. In this case, both the effects of the embodiment shown in FIG. 1A and the effects of the embodiment shown in FIG. 4 can be achieved.
In the aforesaid embodiment, each of the adjustment sections is not limited to the type wherein the length of conveyance of the recording belt 1 is adjusted by the tension rollers. For example, rollers at the adjustment sections may be mechanically moved by an independent movement means to adjust the length of conveyance. Also, the stimulable phosphor layer need not necessarily be provided over the overall surface of the recording belt 1, and the stimulable phosphor layer for several images may be provided intermittently at a part of the recording belt 1. Furthermore, the configurations of the image read-out section 20, the erasing section 30 and other sections are not limited to those in the aforesaid embodiments. For example, as the photoelectric read-out means, the means provided with the long photomultiplier as mentioned above should preferably be used for making the apparatus small. However, it is also possible to use the photoelectric read-out means as shown in FIG. 5 comprising a light guide member having a light input end face extending along the main scanning line and a cylindrical light output end face, and a comparatively small photomultiplier closely contacted with the light output end face of the light guide member. | A radiation image recording and read-out apparatus comprises an endless belt provided with a stimulable phosphor layer, a conveyance system for conveying the endless belt, an image recording section facing the endless belt for exposing the stimulable phosphor layer to radiation carrying an image to have the radiation image stored thereon, and an image read-out section facing the endless belt for irradiating stimulating rays to the image-recorded stimulable phosphor layer and obtaining electric image signals by detecting light emitted by the stimulable phosphor layer in proportion to the stored radiation energy when the stimulable phosphor layer is exposed to the stimulating rays. An erasing section faces the endless belt for eliminating residual radiation energy on the stimulable phosphor layer. The conveyance system is provided with adjustment section at least at two positions for variably adjusting a length of conveyance of the endless belt. | 6 |
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a process for the preparation of polyamines of the diphenylmethane series and to a process for the preparation of polyisocyanates of the diphenylmethane series having reduced color values. In the process of preparing the polyisocyanates, the resultant polyamines are further phosgenated to form the corresponding polyisocyanates of the diphenylmethane series.
[0002] Polyisocyanates of the diphenylmethane series are to be understood as being isocyanates and mixtures of isocyanates of the following type:
[0003] By analogy, polyamines of the diphenylmethane group are to be understood as being compounds and mixtures of compounds of the following type:
[0004] The large-scale preparation of isocyanates by reaction of amines with phosgene in solvents is known and is described in detail in the literature (Ullmanns Enzyklopädie der technischen Chemie, 4th Edition, Volume 13, page 347-357, Verlag Chemie GmbH, Weinheim, 1977). On the basis of that process, polyisocyanate mixtures are obtained which are used as polyisocyanate components in the production of polyurethane foams and other polyurethane plastics produced by the polyaddition process.
[0005] It is generally known that undesirable colorants or color-giving components are also formed in that process, and these are also retained during further processing of the polyisocyanates to polyurethane foams or other polyurethane plastics. Although the intrinsic color of the polyisocyanate polyaddition products does not adversely affect their mechanical properties, substantially colorless products are desired by the consumer. A measure of the change in color of the polyisocyanate is the extinction at various wavelengths.
[0006] Accordingly, it has for a relatively long time been the aim of many experiments and works, which are described in the literature, to reduce the color values of polyisocyanates of the diphenylmethane series. For example, DE-A1-4208359 describes the treatment of such isocyanates with hydrogen in the presence of support catalysts. DE-A1-4232769 describes the addition of amines, ureas and antioxidants to the isocyanate. DE-A1-19815055 describes improving the color of polyisocyanates of the diphenylmethane group by irradiation with light over a prolonged period of time. DE-A1-19804915 describes the brightening of polyisocyanates of the diphenylmethane series by the complicated addition, stepwise in terms of time and temperature, of formaldehyde at the polyamine stage, the polyamine then being converted into the desired isocyanate by phosgenation.
[0007] A disadvantage of all those procedures is that they are technically complex and/or not very efficient.
SUMMARY OF THE INVENTION
[0008] The object of the present invention is, therefore, to provide a process which is technically simple and reliable and by means of which polyisocyanates of the diphenylmethane series having low color values can be prepared. A further object of the present invention is to provide a simple process for the preparation of polyamines of the diphenylmethane series, from which the corresponding polyisocyanates of the diphenylmethane series having low color values can be prepared by phosgenation of the polyamines.
[0009] The object is achieved according to the invention by a process for the preparation of polyamines of the diphenylmethane series, comprising:
[0010] a) reacting aniline and formaldehyde in the presence of an acid catalyst to form polyamines, and
[0011] b) neutralising the reaction mixture from a) with a base,
[0012] wherein at least one alcohol is present during and/or after the neutralisation step, with the molar ratio of the alcohol to the formaldehyde being at least 0.02:1.
[0013] In accordance with the present invention, the alcohol may be added at a point prior to the neutralisation, during the neutralisation, or after the neutralisation of the reaction mixture. In one embodiment of the invention, after neutralisation, the phases are separated, and the alcohol and an additional quantity of a base are added to the organic phase.
[0014] The object is also achieved according to the invention by a process for the preparation of polyisocyanates of the diphenylmethane series, comprising
[0015] a) reacting aniline and formaldehyde in the presence of an acid catalyst to form polyamines,
[0016] b) neutralising the reaction mixture from a) with a base, and
[0017] c) phosgenating the resultant polyamines into the corresponding polyisocyanates,
[0018] wherein at least one alcohol is present during and/or after the neutralisation step, with the molar ratio of the alcohol to the formaldehyde being at least 0.02:1.
[0019] In accordance with this aspect of the present invention, the alcohol may be added at a point prior to the neutralisation, during the neutralisation, or after the neutralisation of the reaction mixture. In one embodiment of the invention, after neutralisation, the phases are separated, and the alcohol and an additional quantity of a base are added to the organic phase.
[0020] The process according to the invention can be carried out either continuously or discontinuously.
[0021] Polyisocyanates with low color values can be produced by the process according to the invention. Color value here is understood to mean the measured absorbance of a solution of polyisocyanate in monochlorobenzene, containing 2 wt. % polyisocyanate, in a layer thickness of 10 mm and at room temperature, against monochlorobenzene at defined wavelengths.
DETAILED DESCRIPTION OF THE INVENTION
[0022] The polyamine or polyamine mixture of the diphenylmethane series which is prepared by the process according to the present invention is obtained by the condensation reaction of aniline and formaldehyde in the presence of an acid catalyst (H. J. Twitchett, Chem. Soc. Rev. 3(2), 209 (1974), M. V. Moore in: Kirk-Othmer Encycl. Chem. Technol., 3rd Ed., New York, 2, 338-348 (1978)). It is not important to the process of the present invention whether the aniline and formaldehyde are first mixed in the absence of the acid catalyst and the acid catalyst is added subsequently, or whether a mixture of aniline and acid catalyst is reacted with formaldehyde.
[0023] Suitable polyamine mixtures of the diphenylmethane series are usually obtained by the condensation reaction of aniline and formaldehyde in a molar ratio of from 20:1 to 1.6:1, preferably from 10:1 to 1.8:1, and a molar ratio of aniline and acid catalyst of from 20:1 to 1:1, preferably from 10:1 to 2:1.
[0024] Commercially, formaldehyde is generally used in the form of an aqueous solution. It is, however, also possible to use other compounds (instead of formaldehyde) that supply methylene groups, such as, for example, polyoxymethylene glycol, para-formaldehyde or trioxane.
[0025] Strong organic and, preferably, inorganic acids have proved to be suitable as acid catalysts. Examples of suitable acids include hydrochloric acid, sulfuric acid, phosphoric acid and methanesulfonic acid. Preference is given to the use of hydrochloric acid.
[0026] In a preferred embodiment of the process, the aniline and the acid catalyst are first combined. In a further step, optionally after the removal of heat, that mixture is mixed in a suitable manner with formaldehyde at temperatures of from 20° C. to 100° C., preferably from 30° C. to 80° C., and is then allowed to undergo a preliminary reaction in a suitable dwell-time apparatus. The preliminary reaction is carried out at temperatures of from 20° C. to 100° C., preferably in the temperature range from 30° C. to 80° C. Following mixing and the preliminary reaction, the temperature of the reaction mixture is brought in steps or continuously, and optionally under excess pressure, to a temperature of from 100° C. to 250° C., preferably from 100° C. to 180° C., and most preferably of from 100° C. to 160° C.
[0027] In another embodiment of the process, it is possible first to mix and hence react the aniline and the formaldehyde, in the absence of the acid catalyst, in the temperature range of from 5° C. to 130° C., preferably from 40° C. to 100° C., and most preferably from 60° C. to 85° C., which forms condensation products of aniline and formaldehyde (so-called aminal). Following the aminal formation, water present in the reaction mixture can be removed by phase separation or other suitable process steps such as, for example, by distillation. In a further process step, the condensation product is then mixed in a suitable manner with the acid catalyst and undergoes a preliminary reaction in a dwell-time apparatus at temperatures of from 20° C. to 100° C., preferably from 30° C. to 80° C. The temperature of the reaction mixture is then brought in steps or continuously, and optionally under excess pressure, to a temperature of from 100° C. to 250° C., preferably of from 100° C. to 180° C., and most preferably of from 100° C. to 160° C.
[0028] The reaction of aniline and formaldehyde in the presence of an acid catalyst to form polyamines of the diphenylmethane group can be carried out in the presence of further substances. These substances include, but are not limited to solvents, salts, and organic and inorganic acids.
[0029] For working-up of the acid reaction mixture, the reaction mixture is neutralised with a base. According to the prior art, the neutralisation is usually carried out at temperatures of, for example, from 90 to 100° C., without the addition of further substances (see H. J. Twitchett, Chem. Soc. Rev. 3(2), 223 (1974)). Suitable bases for neutralising the reaction mixture include, for example, the hydroxides of the alkali and alkaline earth elements. Aqueous NaOH is preferably used as the base.
[0030] In the process according to the present invention, the acid reaction mixture is neutralised in the presence of an alcohol; and/or an alcohol is added to the reaction mixture after it has been neutralised; and/or the aqueous phase is removed from the neutralised reaction mixture, and a base and an alcohol are added to the organic phase that remains. The purpose of the alcohol is to increase the solubility of hydroxyl ions in the organic phase. Any compounds that increase the solubility of the hydroxyl ions and hence their concentration in the organic phase are therefore suitable in principle for the process according to the invention.
[0031] In particular, suitable alcohols for the present invention include, for example, methanol, ethanol, n-propanol, isopropanol, mono- and di-ethanolamine and their N-substituted derivatives, and triethanolamine. Preference is given to the use of methanol. The positive effect of the solubilising alcohols is not limited to the use of the pure substances. It is also possible to use mixtures of alcohols in the process according to the invention.
[0032] In one embodiment of the process according to the present invention, the acid reaction mixture from the reaction of aniline and formaldehyde is neutralised with a base in the presence of an alcohol.
[0033] The neutralisation is advantageously effected by mixing the acid reaction mixture of the aniline/formaldehyde condensation with the base and the appropriate alcohol, and conveying the mixture to a dwell-time apparatus. If suitable dwell-time apparatuses are used (e.g. stirrer vessels), it is also possible for the acid condensation mixture, the base and the alcohol to be mixed directly in the dwell-time apparatus.
[0034] The addition or feeding in of the solubilising alcohol does not necessarily have to be left until the neutralisation stage. On the contrary, it is also possible to introduce the alcohol into the process with one of the starting materials (i.e. the aniline, formalin, and/or hydrochloric acid) at the start of the process. The direct feeding in of the alcohol at any desired point of the acid-catalysed reaction of aniline and formalin is also possible. It is also possible for the alcohol to be added only following the neutralisation (in a continuous process, for example, in a downstream dwell-time apparatus) and to come into contact with the neutralised reaction mixture for a sufficient dwell time. It is also possible to add the alcohol in several portions at different locations and/or at different times in the process, in each case proportionately.
[0035] The dwell time of the reaction mixture in the presence of the alcohol in the neutralisation apparatus or downstream dwell-time apparatus is preferably ≧0.1 minute, particularly preferably from 0.1 to 180 minutes, most particularly preferably from 2 to 120 minutes, most especially particularly preferably from 5 to 60 minutes. In order to prevent boiling below or at a desired temperature, it may be necessary to carry out the process step under elevated pressure.
[0036] The base used for the neutralisation is preferably employed in amounts of greater than 100%, preferably from 101 to 140%, and most preferably from 105 to 120%, of the amount stoichiometrically required for neutralisation of the acid catalyst used. The alcohol or alcohol mixture is used in a molar ratio, relative to the formaldehyde used for the condensation reaction, of at least 0.02:1, preferably from 0.025:1 to 100:1, more preferably from 0.03:1 to 50:1, most preferably from 0.04:1 to 10:1, most particularly preferably from 0.05:1 to 5:1. The effect of the neutralisation with addition of an alcohol on the MDI color is enhanced if it is ensured that the organic phase and the aqueous phase are sufficiently thoroughly mixed in the neutralisation apparatus or downstream dwell-time apparatus. This can be effected by using the methods known in the art, such as, for example, by means of static or dynamic mixers or by generating turbulence.
[0037] Following the neutralisation, the organic phase is separated from the aqueous phase in a separating vessel. If phase separation is not possible due to the use of large amounts of solubilising alcohol, phase separation can be initiated by the targeted addition of water. Alternatively, it is also possible to first remove the alcohol from the neutralised mixture by suitable methods such as, for example, distillation, and then to carry out the phase separation. The product-containing organic phase that remains after separation of the aqueous phase is subjected to further working-up steps (e.g. washing), and then freed of excess aniline and other substances present in the mixture (e.g. further solvents) by suitable methods such as, for example, distillation, extraction or crystallisation.
[0038] In an alternative embodiment of the process according to the invention, the neutralisation is carried out according to the prior art, for example at a temperature of from 90 to 100° C. Separation of the aqueous phase and the organic phase is then carried out by one of the conventional methods, for example, in a separating flask. After the phase separation, the organic phase of the neutralised reaction mixture is mixed with a base, preferably aqueous sodium hydroxide solution, in a dwell-time vessel, and an alcohol is added thereto.
[0039] The base is used in amounts of greater than 1%, preferably from 2 to 140%, especially from 5 to 120%, of the amount stoichiometrically required for the neutralisation of the acid catalyst used for the condensation reaction. The alcohol or alcohol mixture is used in a molar ratio, relative to the formaldehyde used for the condensation, of at least 0.02:1, preferably from 0.025:1 to 100:1, more preferably from 0.03:1 to 50:1, most preferably from 0.04:1 to 10:1, most particularly preferably from 0.05:1 to 5:1. Treatment of the organic phase of the neutralised reaction mixture is carried out, for example, by mixing the organic phase either with the base or with the alcohol or alcohol mixture or with both in a mixing unit and then conveying the mixture to the dwell-time apparatus (for example stirrer vessel, stirrer vessel cascade, flow pipe or recirculating reactor). If suitable dwell-time apparatuses are used, it is also possible for the organic phase to be mixed with the base and the alcohol or alcohol mixture directly in the dwell-time apparatus.
[0040] Treatment of the organic phase of the neutralised reaction mixture with the base and the alcohol or alcohol mixture is preferably carried out for a dwell time of ≧0.1 minute, preferably from 0.1 to 180 minutes, more preferably from 2 to 120 minutes, most preferably from 5 to 60 minutes. In order to prevent boiling below or at a desired temperature, it may be necessary to carry out the process step under elevated pressure.
[0041] The effect on the color of the polyisocyanates of the diphenylmethane group is enhanced if it is ensured that the organic phase and the aqueous phase are sufficiently thoroughly mixed in the dwell-time vessel. This can be effected by using the methods known in the art such as, for example, by means of static or dynamic mixers, or by generating turbulence. After treatment of the organic phase with the alcohol, which is preferably carried out in the presence of the base, further phase separation is carried out and the organic phase is conveyed to the further working-up steps. If phase separation is not possible due to the use of large quantities of solubilising alcohol, phase separation can be initiated by the targeted addition of water. It is also possible, however, to first remove the alcohol from the neutralised mixture by suitable methods such as, for example, by distillation, and then to carry out the phase separation. It is also possible to introduce the aqueous phase containing the base into the neutralisation of the acid reaction mixture from the condensation of aniline and formaldehyde, optionally after addition of water, in order to establish the desired concentration of base.
[0042] The resulting polyamine or polyamine mixture of the diphenylmethane group is reacted, in accordance with known methods, with phosgene in an inert organic solvent to form the corresponding isocyanates. The molar ratio of crude MDA (i.e diphenylmethane diamine) to phosgene is generally such that from 1 to 10 mol, and preferably from 1.3 to 4 mol, of phosgene are present in the reaction mixture per mol of NH 2 group present. For this aspect of the present invention, suitable compounds to be used as inert solvents include chlorinated aromatic hydrocarbons such as, for example, monochlorobenzene, dichlorobenzenes, trichlorobenzenes, the corresponding toluenes and xylenes, and also chloroethylbenzene. Monochlorobenzene, dichlorobenzene or mixtures of these chlorobenzenes are used preferably used as inert organic solvents. The amount of solvent is generally such that the reaction mixture has an isocyanate content of from 2 to 40 wt. %, preferably from 5 to 20 wt. %, based on the total weight of the reaction mixture. When the phosgenation is complete, the excess phosgene and the inert organic solvent or mixtures thereof are removed from the reaction mixture by distillation.
[0043] The crude MDI's prepared by the process according to the invention have a markedly reduced coloring.
[0044] The following examples further illustrate details for the process of this invention. The invention, which is set forth in the foregoing disclosure, is not to be limited either in spirit or scope by these examples. Those skilled in the art will readily understand that known variations of the conditions of the following procedures can be used. Unless otherwise noted, all temperatures are degrees Celsius and all percentages are percentages by weight.
EXAMPLES
Example 1 (Comparison Example)
[0045] 1011 g of aniline and 611 g of a 32% aqueous formaldehyde solution were simultaneously added dropwise at 80° C., over the course of 20 minutes, under a covering of nitrogen, to 200 g of aniline. After the addition was completed, the mixture was stirred for 10 minutes and then phase separation was carried out at a temperature from 70 to 80° C. 300 g of the organic phase were adjusted to a temperature of 35° C. in a nitrogen atmosphere, and then the remainder of the organic phase and 373 g of 32% aqueous hydrochloric acid were added thereto at that temperature, over the course of 30 minutes. When the addition was complete, and after stirring for an additional 30 minutes at that temperature, the mixture was heated to 60° C. over a period of 10 minutes and maintained at that temperature for 30 minutes. The mixture was then heated to reflux temperature (about 105° C.) over the course of 30 minutes, and stirring was carried out for 10 hours under reflux. Then, 123 g of 50% aqueous sodium hydroxide solution and 265 ml of boiling water were added to 684 g of the acid condensation mixture so obtained. After 30 minutes' stirring under reflux (at about 105° C.), phase separation was carried out at from 80 to 90° C. and the organic phase was washed two times with 800 ml of boiling water each time. The organic phase was then freed of excess aniline under reduced pressure. 50 g of the polyamine formed by this process were dissolved in 255 ml of chlorobenzene, heated to 55° C. and added over the course of 10 s, with intensive stirring, to a solution, adjusted to a temperature of 0° C., of 105 g of phosgene in 310 ml of chlorobenzene. While passing phosgene through, the suspension was heated to 100° C. over the course of 45 minutes and then to reflux temperature over a period of 10 minutes. After a further 10 minutes at that temperature, the solvent was distilled off under reduced pressure to a bottom temperature of 100° C. The crude isocyanate was then heated in a distillation apparatus at a pressure of from 4 to 6 mbar, by means of a heating bath heated to 260° C., until the first product passed over, and it was then cooled to room temperature over the course of 5 minutes. 1.0 g of the isocyanate so obtained was dissolved in chlorobenzene and diluted to 50 ml with chlorobenzene. The solution so obtained had an extinction value of 0.198 relative to chlorobenzene at 430 nm.
Example 2 (According to the Invention)
[0046] An acid condensation mixture was prepared according to the procedure described in Example 1 from 838 g of aniline, 420 g of a 32% aqueous formaldehyde solution and 256 g of 32% hydrochloric acid. 74 g of 32% aqueous sodium hydroxide solution and 74 g of methanol were added to 247 g of that acid condensation mixture, and stirring was carried out for 30 minutes at 105° C. After cooling to 60° C., 700 ml of water were added to the reaction mixture and, after phase separation, as described in Example 1, the organic phase was washed with water, and freed of aniline by distillation under reduced pressure. The resulting polyamine was converted into the corresponding isocyanate with phosgene analogously to Example 1. The extinction at 430 nm according to the method described in Example 1 was 0.172 relative to chlorobenzene.
Example 3 (According to the Invention)
[0047] An acid condensation mixture was prepared according to the procedure described in Example 1 from 838 g of aniline, 420 g of a 32% aqueous formaldehyde solution and 256 g of 32% hydrochloric acid. To 222 g of the resulting acid condensation mixture, were added 66 g of 32% aqueous sodium hydroxide solution and 95 g of ethanol, and stirring was carried out for 30 minutes at 105° C. After cooling to 60° C., 700 ml of water were added to the reaction mixture and, after phase separation as described in Example 1, the organic phase was washed with water and freed of aniline by distillation under reduced pressure. The resulting polyamine was converted into the corresponding isocyanate with phosgene analogously to Example 1. The extinction at 430 nm according to the method described in Example 1 was 0.164 relative to chlorobenzene.
[0048] 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. | The invention relates to a process for the preparation of polyamines of the diphenylmethane series, comprising
a) reacting aniline and formaldehyde in the presence of an acid catalyst to form polyamines, and
b) neutralizing the reaction mixture formed in a) with a base,
wherein at least one alcohol is present during and/or after the neutralization step. The molar ratio of the alcohol to the formaldehyde is at least 0.02:1.
In addition, the present invention relates to a process for the preparation of polyisocyanates of the diphenylmethane series, according to the process as described above, additionally comprising:
c) phosgenating the resultant polyamines into the corresponding polyisocyanates of the diphenylmethane series. | 2 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to golf clubs, more specifically to putters.
2. Description of the Related Art
No aspect of golf receives any more attention, analysis and study than putting. In a round of even par golf, two strokes per hole are allocated to putts. Golfers are continually working on ways to improve or enhance their scores by reducing the number of putts used. The relatively simply stated principle of smoothly imparting a rolling motion to the ball for movement along its intended path or line, is actually very difficult to repeatedly and consistently achieve. Part of this problem is that the structure of a number of putters is often not of a type that makes it easy for a golfer to accomplish this seemingly easy task. The number and variety of putters used is great; almost every golfer has a different type of particular preferred club design of choice for use as their putter. Even so, a golfer may experiment with a wide variety of putters and putting strokes should a run or series of rounds occur with excessive putts. One of the key factors is confidence of the golfer in an ability to consistently impart a smooth, controlled uniform stroke to the ball so that it moves along its intended line or path of movement at the desired speed.
SUMMARY OF THE INVENTION
Briefly, the present invention provides a new and improved golf putter which improves a golfer's ability to consistently impart a smooth putting stroke on the ball. The putter includes a club head mounted on a lower portion of a club shaft. The club head has a sole plate portion with heel and toe portions extending upwardly from it. A ball contact member formed of an elastomer is mounted with a retainer plate which extends upwardly from the sole plate portion. The retainer plate extends between the heel and toe portions of the club head rearwardly of the elastomer ball contact member.
An inertial mass or ballast of the club head is mounted on the sole plate portion rearwardly of the retainer plate and aligned opposite a central portion of the ball engaging or contact face. A hosel or socket is formed in the inertial mass to receive the lower portion of the club shaft. The ball engaging face extends between the heel and the toe portions, over the full lateral extent of the ball contact member and vertically across the front upright surface of the contact member.
With the present invention, a substantial portion of the weight of the club head is formed by the inertial mass, which is centrally located behind the ball contacting member. The elastomer ball contact member imparts a smooth motion to the ball with reduced chance of the ball jumping or skipping off the club face when stroked. Further, the club shaft is connected to the club head at this same central location. Thus, the mass of the club is concentrated or focused in the center part of the ball contact area of the putter. This is also the point of connection of the club shaft to the club head. An alignment indicator or guide is formed on the club head to indicate this central axis or line.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a front isometric view of a golf putter according to the present invention, with portions thereof shown in phantom.
FIG. 2 is a front elevation view of the golf putter of FIG. 1 .
FIG. 3 is a plan view of the golf putter of FIG. 1 .
FIG. 4 is a rear elevation view of the golf putter of FIG. 1 .
FIG. 5 is a rear isometric view of the golf putter of FIG. 1 .
FIG. 6 is a front isometric view of another embodiment of a golf putter according to the present invention, with portions thereof shown in phantom.
FIG. 7 is a side elevation view, taken partly in cross-section, along the line 7 — 7 of FIG. 6 .
FIG. 8 is a front elevation view of the golf putter of FIG. 6 .
DETAILED DESCRIPTION OF INVENTION
In the drawings, the letter P designates generally a new and improved putter according to the present invention. The putter P includes a club or putter head H mounted on a lower portion 10 of a club shaft 11 . The club shaft 11 is conventional and may be of any suitable length in its upward extent from the lower portion 10 mounted with the club head H. The club shaft 11 , as is conventional, has a club grip (not shown) mounted at its upper end. The club grip may be of any of numerous commercially available types.
The club head H is formed of a suitable metal alloy, such as a manganese alloy and includes a sole plate or face member 12 . A heel portion 14 and a toe portion 16 are formed extending upwardly from the sole plate portion 12 of the club head H. The heel portion 14 and toe portion 16 are spaced laterally from each other by a gap 18 on a front portion 20 of the sole plate 12 . The gap 18 is formed inwardly of a retainer plate 22 which extends upwardly from the sole plate 12 . The retainer plate 22 is formed of the same material as the sole plate 12 , heel portion 14 , and toe portion 16 and extends laterally between rear portions 24 and 26 of the heel portion 14 and the toe portion 16 .
With the present invention, a ball contact member 28 is provided in the club head H. The ball contact member 28 is formed of an elastomer, preferably a polyurethane elastomer of suitable hardness, about ⅜″ thick and about 3″ in width by ⅞″ in height. For example, a polyurethane elastomer having a D scale durometer hardness of at least 65 is suitable for use as the ball contact member 28 . The ball contact member 28 is fitted in and fixedly mounted in the gap 18 on the club head H. The ball contact member 28 is mounted by a suitable strength adhesive, such as an epoxy resin, on a rear surface 30 to a front surface 32 of the retainer plate 22 . Similarly, the ball contact member 28 is mounted along a first side surface 34 to an inner surface 36 of the heel portion 14 . The ball contact member 28 is also mounted in the same manner along a second side surface 38 to an inner surface 40 of the toe portion 16 .
The elastomer ball contact member 38 has a ball contact surface 42 formed extending laterally across the full frontal extent of a club face 44 between the metal heel and toe portions 14 and 16 of the club head H. The lateral extent of the ball engaging surface 42 of the ball contact member 38 is preferably three inches or more, thus at least double the diameter of a standard U.S. golf ball. Thus, unless the putter P is intentionally misaligned, the ball when stroked is contacted by the elastomer mass of the ball contact member 28 . Contact with the elastomer ball contact member 28 imparts a smooth motion to the ball with reduced chance of the ball jumping or skipping off the club face in the event that slightly irregular or excessively strong stroke is imparted to the ball.
The ball contact surface 42 of contact member 28 extends vertically with substantially no loft upwardly the full vertical extent of the club face 44 and retainer member 24 between the metal heel and toe portions 14 and 16 , respectively. Thus, regardless of the height that the club head H is above the ground when the ball is stroked during a putting stroke, the ball begins to roll when it is contacted by the elastomer mass 28 of the ball contact member, again reducing the chance of the ball jumping or skipping off the club face 44 . Also, a softer touch can be used in the putting stroke.
The club head H includes an inertial mass or ballast portion 46 formed rearwardly of the retainer plate 22 and ball contact member 28 . The inertial mass 46 extends laterally along the retainer plate 28 over a width spaced about a vertical center plane passing through the center of gravity, as indicated at 48 of the ball contact member 28 . The inertial mass 46 is thus located opposite a central portion 50 of the ball contact surface 42 . In this manner, a substantial portion of the weight of the club head H is represented by the inertial mass 46 , which is centrally located behind the ball contacting member 28 .
The base or sole plate 12 of the club head H includes side flange members 52 and 54 formed extending rearwardly from the retainer plate 22 and laterally from side walls 56 and 58 of the inertial mass 46 . The flange members 52 and 54 along with the base plate portion 12 form a stable, broad generally relatively flat rest or support surface. A golfer may thus rest these portions of the club head H on the ground. This assists the golfer in gripping the club and achieving proper club shaft hand alignment during “setup” before the actual putting stroke, due to the substantial lateral extent of the base plate portion 12 of the club head H.
The inertial mass 46 of the club head H also has a hosel or socket 60 formed extending downwardly therein to receive the lower portion 10 of the club shaft 11 . The hosel 60 in the inertial mass 46 has a central longitudinal axis 62 located in a plane passing downwardly through and intersecting the vertical plane 48 formed through the center of gravity of inertial mass 46 . The longitudinal axis 62 of the hosel 60 is formed at a suitable angle from the vertical center plane 48 , usually between 20° and 30° and preferable approximately 26°, although this may vary depending upon the height of the club user.
The ball contact member 28 similarly has a vertical center plane, as indicated a 70 , passing through its center of gravity. The vertical center plane 70 through the ball contact member 38 is aligned with the vertical center plane 48 through the inertial mass 46 at its center of gravity. In this manner, a longitudinal axis of the club shaft 11 co-extensive with axis 62 of the hosel 60 intersects the aligned vertical center planes 48 and 70 through the centers of gravity of the inertial mass 46 and the ball contact member 38 .
Thus, the club shaft 11 is connected to the club head H at a central location aligned with the substantial portion of the weight of the club head H, represented by the inertial mass 46 . Thus, the mass of the putter P is concentrated or focused in the central part of the ball contact area 50 of the putter P. As has been noted, this is also the point of connection of the club shaft 11 to the club head H.
An aiming indicator or alignment guide groove 80 is formed on the club head H extending from the ball contact surface 42 across a top surface 82 of the ball contact member 28 and a top surface 84 of the retainer plate 22 and a top surface 86 of the inertial mass 46 . The alignment guide 80 is formed in alignment with the vertical planes 48 and 70 formed through the centers of gravity of the ball contact member and the inertial mass 46 . Thus, a user of the putter P can with guide 80 align a substantial portion of mass of the club, represented by the inertial mass 46 and the ball contact member 28 , as well as the connection point between the club shaft 11 and the club head H, with the center line of the ball in aligning a putting stroke.
For additional alignment accuracy, side aiming indicators or alignment guides 88 and 90 are formed in the heel portion 14 and toe portion 16 of the club head H. The alignment indicator 88 is formed in heel portion 14 parallel to aiming guide 80 inwardly of surface 36 extending across an upper surface 92 . Similarly, the alignment indicator 90 is formed parallel to aiming guide 80 outwardly from surface 40 , and extending across an upper surface 94 .
In some instances, golfers prefer to have a slight clicking noise or sound when the ball is stroked during a putting stroke. With an elastomer insert, such as the ball contact member 28 , this does not occur. For golfers who prefer the noise or sound emitted when the ball is stroked during a putting stroke, a metal insert 100 of brass or other suitable material is integrally formed into the ball contact member across the ball contact surface 42 . The metal insert 100 , for example, may be about ½″ in height, 2-⅜″ in width and extend approximately ¼″ into the ball contact face 42 . It is noted that there is a portion 102 (FIG. 7) of the elastomer insert 28 present behind the metal insert 100 and in front of surface 32 of retainer plate 22 . The portion 102 exerts a deadening effect and the metal insert 100 does not increase the likelihood of skipping of the ball off of contact surface 42 .
The foregoing disclosure and description of the invention are illustrative and explanatory thereof, and various changes in the details of the illustrated apparatus and construction and method of operation may be made without departing from the spirit of the invention. | A golf putter improves a golfer's ability to consistently impart a smooth putting stroke on the ball. The putter has an elastomer insert extending over a ball striking surface formed on the head of the club head. An inertial mass or ballast is formed at a rear central portion of the club head, with center portions of the ballast mass aligned with the vertical center line of the ball striking surface. The shaft portion of the putter is connected to the club head so that the longitudinal axis of the shaft intersects the center line of the club head and the inertial mass. The club head also has a base plate portion to assist the golfer in club grip and alignment during “set up” before the actual putting stroke. | 0 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This patent application claims the benefit of the provisional patent application No. 61/280,663, which was filed on Nov. 6, 2009.
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 directed to a minimally invasive surgical apparatus in the form of a cannula that is designed for use in minimally invasive surgical procedures such as general laparoscopic surgery, single incision laparoscopic surgery, natural orifice transluminal endoscopic surgery, thoracoscopic surgery, arthroscopic surgery and robotic surgery. More specifically, the present invention is directed to a minimally invasive surgical apparatus comprising a cannula having a length with opposite proximal and distal ends and with differing characteristics of malleability and elasticity along the cannula length. A proximal portion of the cannula length is more rigid than a distal portion of the cannula length, and the distal portion of the cannula length can be moved to a particular position or into a particular shape relative to the proximal portion and substantially stay in that position or shape. The cannula is designed for use with conventional sources of suction and irrigation and their controllers. Alternatively, the cannula can be provided with an actuator at its distal end that can be activated from inside a body cavity to selectively provide suction and/or irrigation at the cannula distal end in minimally invasive surgical procedures.
[0005] (2) Description of the Related Art
[0006] In large, open incision surgery, a suction cannula connected by a length of sterile tubing to a centralized vacuum system is always available to the surgeon. If the surgeon needs to evacuate blood or other bodily fluids from a surgical site in the open incision, the surgeon or an assistant will pick up the suction cannula and direct the distal end of the cannula to the area of interest at the surgical site. Continuous suction provided by cannulas of this type has been available in operating rooms for many years. Suction cannulas used for this purpose are well known in the prior art and have been available commercially for many years.
[0007] Minimally invasive surgery is a phrase often used to describe different types of surgical procedures where the large, open incision of conventional surgery is replaced by surgical techniques that allow surgical procedures to be performed through smaller incisions. Laparoscopic surgical procedures and other minimally invasive surgical procedures typically employ a pressurized gas to create and maintain an enlarged body cavity or space for performing the surgical procedure. Pressurized gas is injected through the abdominal wall or through the layers of skin of the patient's body to insufflate and expand the abdominal wall or layers of skin and create the space or cavity inside the body for conducting the surgical procedure. Without this created space, the surgeon would not be able to freely manipulate and/or view surgical instruments and tissue in the body when conducting the surgical procedure. Other types of minimally invasive surgery that do not employ insufflation include thoracoscopic surgery and arthroscopic surgery.
[0008] Providing suction and/or irrigation in minimally invasive surgical procedures employing a distending gas is typically provided by a long, rigid cannula that is also inserted through a small incision in the abdominal wall or skin layers to position the distal end of the cannula at a desired position at the surgical site. The opposite proximal end of the cannula typically has a hand piece that has manual actuators for valves in or on the hand piece. The valves control the supply of suction and/or irrigation liquid through the cannula. Manual manipulation of the hand piece by the surgeon outside of the patient's body moves the distal end of the cannula inside the patient's body. An example of such a prior art hand piece and cannula is disclosed in the U.S. patent of Cover, et al. U.S. Pat. No. 6,652,488. This common prior art cannula provides both the functions of suction and irrigation in a single device. When suction or irrigation is desired at the surgical site, a suction or irrigation actuator on the hand piece is manually depressed and the vacuum pressure or irrigation liquid is transmitted through the cannula to the distal end of the cannula at the surgical site.
[0009] Prior art suction cannulas of the type described above have also been used in both open incision and minimally invasive surgical procedures employing electric energy surgical instruments to evacuate smoke generated by the instruments during a surgical procedure. This is particularly useful in laparoscopic surgery procedures to evacuate smoke that creates a haze that is difficult to see through to enable the surgeon to clearly view the surgical site throughout the procedure.
[0010] Extensions of laparoscopic surgery procedures that also employ suction cannula of the type described above include robotic assisted laparoscopic surgery, single incision laparoscopic surgery and natural orifice transluminal endoscopic surgery (NOTES).
[0011] The long, rigid cannulas used to provide suction and/or irrigation in minimally invasive procedures have been found to be disadvantaged in that positioning the distal end of the long, rigid cannula at a desired position at a surgical site inside a body cavity requires manual manipulation of the opposite proximal end of the long, rigid cannula from outside the body. This makes it difficult to accurately position the cannula distal end at a desired position inside the body cavity. In addition, selectively providing suction and/or irrigation to the surgical site at the distal end of the long, rigid cannula requires manual activation of actuators located on the hand piece at the opposite proximal end of the long, rigid cannula. This complicates the use of the cannula in maintaining the cannula distal end at a desired position while manipulating actuators on the cannula proximal end.
[0012] Furthermore, in traditional laparoscopic surgical procedures a 5 mm incision is made in the abdominal wall and a port is inserted in the incision. Surgical instruments used in the surgical procedure are inserted through the port. When suction is needed during the surgical procedure, the surgeon must first remove the instrument currently being used from the port, and then insert the suction cannula through the port. During general surgery, it is not uncommon for the surgeon to swap out their surgical instrument for a suction cannula an average of five to ten times during a single procedure. In order to allow the surgical instrument to remain in the port it would be necessary to make another incision in the abdomen and place an additional port in that incision.
[0013] The dissatisfaction with current suction cannula is even more apparent in robotic surgery where there is a need for greater surgeon autonomy in regard to suction control during a surgery. While the surgeon operates across the room at a counsel, an assistant must sit at the surgery table to provide retraction, suction, irrigation, insertion of sutures, entrapment and removal of dissected tissue, as well as port removal and closure.
SUMMARY OF THE INVENTION
[0014] The present invention provides a new and improved suction and/or irrigation apparatus for minimally invasive surgery in the form of a tubular cannula that provides surgeon autonomy while reducing the size of the abdominal wall opening required for entry of the cannula through the abdomen. The apparatus is a stand-alone apparatus that provides the benefits of less operative time, does not require a separate incision and a port inserted, is surgeon controlled, can be manufactured at low cost, can be integrated with current operating room sources of suction or irrigation and does not add complexity to the laparoscopic surgical procedure or a robotic surgery system. With the elimination of a need for an additional port, the apparatus can be used without taking an instrument out of the abdomen.
[0015] The apparatus is comprised of a tubular cannula having a length with different degrees of malleability. In one embodiment of the apparatus, an actuator is provided at the distal end of the cannula length that is actuated inter-abdominally (or inside a body cavity) to selectively supply suction and/or irrigation to a minimally invasive surgical site. The apparatus of the invention allows the cannula distal end to remain inside a body cavity surgical site where the distal end can be easily manipulated by a surgical instrument to a desired location inside the body cavity and substantially stay at that location when released by the instrument. The embodiment of the apparatus having an actuator at the distal end of the cannula also allows the actuation of the actuator from inside the body cavity by a surgical instrument to selectively supply suction and/or irrigation liquid to the desired location of the surgical site.
[0016] The cannula has a length with opposite proximal and distal ends. The proximal end of the cannula is adapted to be connected with conventional suction and irrigation sources that are operated by a conventional controller for such sources where the controller includes electrically operated valves or other similar devices that are responsive to an electric signal. In some embodiments of the cannula conventional controls for the source of suction (vacuum) may be used such as mechanical valves, for example, trumpet valves. The length of the cannula has different characteristics of malleability. What is meant by a “malleable” characteristic is the ability to be shaped or formed. A more malleable portion of the cannula is easily bent or shaped where a less malleable portion resists bending or shaping. The cannula has a small exterior diameter dimension of about 3 mm in size. The small size allows the cannula to be used through a puncture site in the abdomen as opposed to an incision and port, leaving a significantly smaller scar than a trocar or port site. Other embodiments of the cannula could have an exterior diameter dimension larger than 3 mm.
[0017] In a preferred embodiment of the cannula the proximal portion or first section is substantially straight and substantially rigid. In other embodiments the proximal portion or first section of the cannula length is malleable, enabling this portion of the cannula to be inserted through the abdominal wall where the more distal portion of the cannula extending both externally and internally of the abdomen can be bent without buckling and obstructing the lumen of the cannula. In the preferred embodiment permanent deformation may occur if a shaping or bending force is applied that has enough force to bend the rigid first section of the cannula.
[0018] A distal portion or second section of the cannula length that is adjacent the distal end of the cannula has a greater characteristic or degree of malleability. In one embodiment of the cannula the distal portion or second section of the cannula can be moved by a surgical instrument to a desired location inside a body cavity and substantially stay at that location when released by the instrument.
[0019] The different characteristics of malleability in the first and second sections of the cannula can be achieved by extruding these sections of the cannula of materials having different characteristics of malleability. Alternatively, the different characteristics of malleability in the first and second sections of the cannula can be achieved by embedding a deformable wire or wires in the cannula sections where the wire or wires have different characteristics of malleability. Furthermore, instead of embedding the wire or wires in the extruded first and second sections of the cannula, the cannula could be constructed from an inner PVC tube with the wire or wires extending along the length of the exterior surface of the PVC tube, and a silicone tube positioned over the wire or wires and over the PVC tube with the silicone tube sandwiching the wire between it and the PVC tube.
[0020] In one embodiment of the cannula a tip is provided at the distal end of the cannula. The tip provides an area to be grasped by a surgical instrument manipulated by the surgeon. The tip has a gripping surface that resists the grasping instrument slipping from the tip when the tip is wet from bodily fluids.
[0021] In one embodiment of the cannula an actuator is provided in the tip of the cannula. The actuator can be any type of actuator that can control a supply of suction pressure and/or irrigation liquid in response to actuation of the actuator. For example, the actuator could be an electric switch that communicates with a controller of a source of suction or irrigation. The switch is sealed inside the cannula tip between the internal lumen of the cannula and the exterior surface of the cannula. Electrical conductors extend from the switch. The conductors are embedded in and run along the length of the cannula from the switch at the distal end of the cannula to the proximal end of the cannula. The conductors are sealed inside the cannula length between the exterior surface of the cannula and the interior surface of the cannula lumen. One or both of the electrical conductors could be the wire or wires that extend along the length of the first and second sections of the cannula and provide the different characteristics of malleability and elasticity along the first and second sections of the cannula length.
[0022] At the cannula proximal end the conductors exit the cannula and are accessible for electrical communication to a conventional controller of a suction and/or irrigation source. When the conductors are electrically connected to the controller, activation of the cannula switch transmits a signal to the controller that in turn controls an electromechanical valve of the source of suction to provide suction pressure to the cannula, or controls an electromechanical valve of the source of irrigation liquid to provide irrigation liquid to the cannula.
[0023] The switch in the cannula tip can be actuated by grasping the tip with a surgical grasper and exerting a compressive force on the tip. Alternatively, the switch can be activated by merely exerting a compressive force on one side of the tip with a separate surgical instrument. Still further, the switch could be activated by merely positioning a surgical instrument adjacent the tip. For example, the switch could be a magnetic switch that is activated by positioning a magnetic surgical instrument adjacent the tip. Additionally, a pair of separate switches could be provided at the cannula distal end, with one switch activating the source of suction and the other switch activating the source of irrigation. The two switches would be spaced along the length of the cannula distal end so that both switches could not be activated simultaneously.
[0024] In embodiments of the cannula that do not employ an electric switch, activation may be mechanically driven by a conventional trumpet valve at the cannula proximal end, by a conventional foot-operated actuator, or by a mechanical actuator provided at the cannula distal end.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] Further features of the invention are set forth in the following detailed description of the invention and in the drawing figures.
[0026] FIG. 1 is a schematic representation of the minimally invasive surgical apparatus of the invention and an exemplary environment in which the apparatus is used.
[0027] FIG. 2 is a schematic representation of one embodiment of the apparatus of the invention.
[0028] FIG. 3 is a schematic representation of a further embodiment of the apparatus of the invention.
[0029] FIG. 4 is a schematic representation of a further embodiment of the apparatus of the invention having an actuator at its distal end.
[0030] FIG. 5 is a schematic representation of the construction of the tip of the apparatus of FIG. 4 removed from the cannula distal end, and the actuator of the apparatus inside the tip.
DETAILED DESCRIPTION OF THE INVENTION
[0031] The minimally invasive surgical apparatus 10 of the present invention is designed for use with conventional sources of suction pressure and irrigation liquid typically employed in surgical procedures as well as their controllers. Because suction and irrigation devices of this type are known in the art, and because controllers for devices of this type are known in the art, they will not be described in detail herein.
[0032] The minimally invasive surgical apparatus 10 of the invention comprises a tubular cannula 12 having a length with opposite proximal 14 and distal 16 ends. The cannula 12 is constructed of biocompatible materials that are typically used in cannula or catheter constructions. The cannula proximal end 14 is provided with a conventional connector that will connect the cannula to standard tubing. Connecting the opposite end of the standard tubing to a source of suction pressure and/or a source of irrigation liquid communicates the inner lumen of the cannula 12 with the source of suction pressure and/or the source of irrigation liquid and thereby communicates the suction or liquid through the cannula length to the cannula distal end 16 .
[0033] The length of the cannula 12 is comprised of two different sections, a first section 22 and a second section 24 , in one embodiment of the cannula 12 . A further embodiment of the cannula 12 includes a third section 26 . The two sections 22 , 24 or three sections 22 , 24 , 26 are continuous and the cannula has a smooth continuous exterior surface from its proximal end 14 to the distal end 16 and a smooth continuous interior surface surrounding the lumen from its proximal end 14 to its distal end 16 . The sections of the cannula have distinct characteristics of malleability. As stated earlier, what is meant by the characteristic of malleability is the ability to be shaped or formed, as is the common understanding. A more malleable section of the cannula is easily bent or shaped where a less malleable section of the cannula is more difficult to bend or shape.
[0034] The cannula first section 22 extends from the cannula proximal end 14 along the cannula length toward the cannula distal end to an intermediate point 28 along the cannula length. In a preferred embodiment of the cannula 12 the first section 22 is substantially straight and substantially rigid. The first portion of the cannula length that extends along the cannula first section 22 is constructed of a biocompatible metal or polymer. In other embodiments of the cannula the first section 22 could be constructed of materials that give the cannula first section 22 a lesser characteristic of malleability and a greater characteristic of elasticity. This enables the cannula first section 22 to be positioned or inserted through an abdominal wall where the first section 22 , extending both externally and internally of the abdominal wall can be bent without buckling and/or obstructing the inner lumen of the cannula. The outer diameter of the cannula first section 22 is preferably 2-3 mm and the length of the cannula first section 22 is preferable around 30 cm. The smaller external diameter dimension of the cannula 12 enables it to be inserted through the abdominal wall by making a stab puncture in the abdominal wall. This eliminates the need for a separate incision in the abdominal wall and the insertion of a trocar or port through the incision to accommodate the cannula. Preliminary studies have shown that the smaller outer diameter of the cannula 12 does not affect suction capabilities, does not injure organs, will remove blood at an efficient rate and is efficient at breaking up a clot. In other embodiments of the cannula 12 the outer diameter dimension could be larger than 3 mm.
[0035] The cannula second section 24 extends from the cannula first section 22 or from the intermediate point 28 on the cannula length toward the cannula distal end 16 to a distal end 32 of the second section 24 . In the embodiment of the cannula 12 shown in FIG. 2 the distal end 32 of the second section 24 is also the distal end 16 of the cannula 12 . In the embodiment of the cannula 12 shown in FIG. 3 the distal end 32 of the second section 24 is an additional intermediate point 32 on the length of the cannula. The cannula second section 24 has an outer diameter dimension of 2-3 mm and a length of around 10 cm. This portion of the cannula length occupied by the cannula second section 24 has a greater characteristic of malleability than the cannula first section 22 . Preferably, the cannula second section 24 is substantially inelastic. This enables the cannula second section 24 to function as a joint between the cannula proximal end 14 and the cannula distal end 16 . The greater malleability of the cannula second section 24 limits or substantially reduces any forces transmitted from the cannula distal end 16 to the cannula first section 22 that are the result of movement of the cannula distal end 16 . The inelastic characteristic of the cannula second section 24 also enables the cannula distal end 16 to be freely manipulated with a surgical instrument within the body cavity operative space without experiencing any restrictions to the movement of the cannula distal end 16 from the less malleable or rigid characteristics of the cannula first section 22 . The cannula second section 24 can be formed as a continuous extrusion of materials having a greater characteristic of malleability than the cannula first section 22 . Alternatively, the cannula second section 24 can be formed as a continuous extension from the cannula first section 22 and of a biocompatible polymer that is substantially inelastic with a length of wire 33 extruded in the cannula second section 24 . The gauge of the wire 33 would be less than the wall thickness of the cannula second section 24 . Alternatively, a lumen for the wire 33 could be left in the cannula second section 24 and the wire 33 snaked through the lumen. The wire 33 extending through the cannula second section 24 would enable the cannula second section to be moved to a desired position or shape inside the body cavity by the surgeon grasping the cannula with an instrument adjacent the second section distal end 32 , with the wire 33 holding the cannula second section substantially in the position or shape after the instrument is removed from the second section. Still further, rather than embedding a deformable wire 33 in the extruded length of the cannula second section 24 , the cannula second section 24 could be comprised of an inner tube covered with an outer tube with the deformable wire 33 sandwiched in between. For example, the cannula second section 24 could be constructed of an inner PVC tube with the deformable wire 33 laying along the exterior surface of the length of the PVC tube, and with a silicone tube surrounding the deformable wire 33 and the PVC tube and extending along the length of both the wire 33 and the PVC tube. Still further, the cannula second section 24 could be formed from an inner tube and an outer tube as described above, with a pair of deformable wires 33 extending between the two tubes and along the length of the cannula second section 24 . The wire 33 or pair of wires 33 provide the ability to the cannula second section 24 to remain inside a body cavity and be moved to a desired position or into a particular shape relative to the body cavity and the cannula first section 22 by a surgical instrument held by the surgeon, and substantially remain in the position or shape when released by the instrument. The wire 33 or pair of wires 33 also may function as one or a pair of electrical conductors for the actuator at the cannula distal end.
[0036] The embodiment of the cannula 12 shown in FIG. 3 has the same construction as the embodiment of FIG. 2 described above with the addition of the third section 26 . The third section 26 of the cannula length is a tubular tip. The portion of the cannula length defined by the third section 26 is less malleable than the second section 24 of the length of the cannula. The cannula third section 26 extends from the cannula second section 24 or the additional intermediate point 32 on the cannula length to the cannula distal end 16 . The cannula third section 26 has an outer diameter of 2-3 mm and a length of about 3 cm. The tip of the cannula third section 26 provides an exterior gripping surface that can be grasped by a surgical instrument and resist slipping of the instrument even when the surface is wet.
[0037] FIG. 4 is a representation of an embodiment of the cannula 12 having an actuator on the third section. FIG. 5 is an enlarged, partial view of the cannula 12 of FIG. 4 . In FIG. 5 , the cannula third section 26 is shown comprised of an inner tubular member 34 and an outer tubular member 36 that are connected together at their opposite ends by annular seals 38 . This construction creates a cylindrical interior void or volume within the cannula third section 26 between the inner 34 and outer 36 tubular members. The inner cylindrical volume of the cannula third section 26 is sealed by the annular seals 38 at the opposite ends of the third section. The inner tubular member 34 is more rigid than the outer tubular member 36 . The outer tubular member 36 is malleable and elastic and can be deflected radially inwardly toward the inner tubular member by a moderate force exerted on the exterior surface of the cannula third section. Alternatively, the third section 26 of the cannula could be comprised of an inner tube 34 that is an extension of the inner tube of the cannula second section 24 described above, and an outer tube 36 that is an extension of the outer tube of the cannula second section 24 discussed above. The two deformable wires 33 that extend through this embodiment of the cannula second section 24 described above would then also be employed as the electrical connectors to the actuator.
[0038] The embodiment of minimally invasive surgical apparatus of the invention shown in FIG. 5 also comprises an actuator 40 that is sealed inside the cylindrical interior volume of the cannula third section 26 . The actuator can be any type of actuator that can control a supply of suction pressure and/or irrigation liquid in response to actuation of the actuator. For example, the actuator could be an electric switch that communicates with a controller of a source of suction or irrigation. The actuator 40 could also be a pneumatic actuator, or a pressure switch type actuator, or a mechanical actuator. An exemplary embodiment of the actuator as a switch 40 is schematically shown in FIG. 5 . The switch 40 comprises a plurality of spaced electrically conductive rings 42 arranged along the length of the cannula third section 26 , and a plurality of parallel bars 44 that extend along the length of the cannula third section 26 . The conductive rings 42 are supported on an outer surface of the inner tubular member 34 of the cannula third section 26 and the conductive bars 44 are supported on an inner surface of the outer tubular member 36 of the cannula third section 26 . The rings 42 and bars 44 are spaced radially from each other on opposite sides of the cylindrical interior bore of the cannula third section 26 . In other embodiments of the apparatus the actuator could be located at different positions along the cannula length and is not limited to being positioned at the distal end of the cannula length.
[0039] An electrical conductor 46 is connected to each of the electrically conductive rings 42 and a separate electrical conductor 48 is connected to each of the electrically conductive bars 44 . The electrical conductors 46 , 48 are represented schematically by the dashed line shown in FIGS. 1 , 4 and 5 . These two electrical conductors 46 , 48 extend from the cannula third section 26 , through the cannula second section 24 , through the cannula first section 22 and exit the cannula 12 at the cannula proximal end 14 . Preferably, the electrical conductors 46 , 48 are embedded in the cannula 12 between the interior surface of the lumen and the exterior surface of the cannula 12 . This construction seals the electrical conductors 46 , 48 along the entire length of the cannula.
[0040] Exerting a moderate force on the exterior of the cannula third section 26 will move at least one of the electrically conductive bars 44 inside the cannula third section 26 radially inwardly until it makes contact with at least one of the electrical conductive rings 42 . This contact between the bar 44 and ring 42 completes a circuit through the switch in the cannula third section. The electrical conductors 46 , 48 transmit an electric signal through the length of the cannula 12 in response to actuation of the switch. Actuating the switch 40 can be accomplished by exerting a compressive force on the cannula third section 26 by grasping the cannula third section 26 between the jaws of a surgical grasper. Alternatively, this could be accomplished by exerting a force on the exterior of the cannula third section 26 that is sufficient to move one of the conductive bars 44 into contact with one of the conductive rings 42 . Still further, a variant of the exemplary switch depicted in FIG. 5 could be employed in the cannula third section 26 that is responsive to merely positioning a surgical instrument adjacent to the cannula third section 26 , for example a magnetic switch that is responsive to a magnetic surgical instrument positioned in close proximity to the switch.
[0041] FIG. 1 shows one exemplary environment of the apparatus of the invention 10 being employed in a laparoscopic surgical procedure. As depicted in FIG. 1 , the cannula 12 has been inserted through the abdominal wall 52 and the cannula first section 22 is positioned traversing the abdominal wall 52 . The cannula third section 26 has been positioned adjacent an intra-abdominal surgical site 54 . The greater degree or characteristic of malleability of the cannula second section 24 allows the cannula third section 26 to remain at its placed position.
[0042] In the exemplary environment shown in FIG. 1 , the cannula first section 22 is shown held in place traversing the abdominal wall by a restrictive or stabilizing element 56 . The stabilizing element 56 is constructed as a thick, disc-shaped structure of a foam or other similar material having moderate elasticity. The cannula first section 22 is inserted through a center aperture of the disc-shaped stabilizing element 56 and is held there solely by friction engagement. The stabilizer element 56 may be secured and sealed to the exterior of the abdominal wall by adhesives, sutures, surgical staples or other equivalent means. The friction engagement between the cannula first section 22 and the stabilizer element 56 enables the cannula 12 to be moved in and out of the abdomen through the stabilizing element 56 and rotated relative to the abdomen while the stabilizing element limits the pitch and yaw of the cannula first section 22 . As an alternative to the stabilizing element 56 , a ball and socket construction may be used.
[0043] Due to the small outer diameter dimensions of the cannula 12 , a stabilizing element such as those discussed above may not be necessary. It is contemplated that the cannula 12 will be inserted through the abdominal wall with a stab puncture much like that created by a suture passer. A sharp stylette will be placed through the lumen of the cannula 22 so that the stylette tip projects from the cannula distal end 16 . The stylette tip will be used to puncture through the abdominal wall followed by the cannula 12 passing through the puncture. From outside the abdomen, the surgeon will then remove the stylette from the lumen of the cannula 12 . It is also contemplated that with a stab incision or puncture, the elasticity of the skin around the cannula 12 will provide sufficient constriction that a separate stabilizing element will not be needed for stability. In other embodiments the cannula could have an outer diameter dimension larger than 3 mm.
[0044] A length of conventional, flexible suction tubing 64 is connected to the cannula proximal end 14 . The opposite end of the tubing 64 is connected to a conventional controller 66 that communicates with a source of vacuum pressure 68 . The controller 66 selectively controls the supply of vacuum pressure from the vacuum pressure source 68 to the length of tubing 64 . The controller 66 also communicates with a source of irrigation liquid 72 and controls the supply of irrigation liquid to the length of tubing 64 . The controller 66 is conventional and can be any type of controller known in the art. In the exemplary environment shown in FIG. 1 , the controller 66 includes a pair of electrically operated valves 74 , 76 that respectively control the supply of suction pressure and irrigation liquid to the tubing 64 .
[0045] A pair of electrical conductors 78 , 82 are represented by a dashed line extending from the cannula proximal end 14 to the controller 66 . The electrical conductors 78 , 82 are connected with the electrical conductors 46 , 48 of the cannula 12 and provide electrical communication between the cannula switch 40 and the controller valves 74 , 76 . In the illustrative example of FIG. 1 , depending on whether the source of suction pressure or the source of irrigation liquid is activated by the controller 66 , actuation of the cannula switch 40 transmits a signal through the cannula electrical conductors 46 , 48 and through the pair of electrical conductors 78 , 82 to the controller 66 that results in the opening of one of the controller valves 74 , 76 that in turn controls the supply of suction pressure or irrigation liquid through the flexible tubing 64 and the length of the cannula 12 to the cannula distal end 16 .
[0046] With the construction of the minimally invasive surgical apparatus described above, a cannula is provided with a switch at its distal end that is actuated at a laparoscopic surgery site to selectively supply suction or irrigation liquid to the surgery site from a suction source or an irrigation liquid source external to the surgery site. In addition, the cannula of the invention described above allows the cannula distal end to remain at a desired position relative to the laparoscopic surgery site.
[0047] As various modifications could be made in the constructions and methods herein described and illustrated without departing from the scope of the invention, it is intended that all matter contained in the foregoing description or shown in the accompanying drawings shall be interpreted as illustrative rather than limiting. Thus, the breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims appended hereto and their equivalents. | A minimally invasive surgical apparatus in the form of a cannula has a length with opposite proximal and distal ends, and differing characteristics of malleability along the cannula length. A switch can be provided on the cannula adjacent the distal end. The switch can be intra-abdominally activated to selectively provide suction and/or irrigation in minimally invasive surgical procedures such as general laparoscopic surgery, single incision laparoscopic surgery, natural orifice transluminal endoscopic surgery and robotic surgery. | 0 |
BACKGROUND OF THE INVENTION
[0001] The invention relates to a turbopump comprising a turbine fed with hot gas, a pump driven by the turbine and fed with liquid fluid, and a hot gas exhaust pipe situated downstream from the turbine.
[0002] Such turbopumps are known, e.g. for feeding propellant to the combustion chamber of a rocket engine.
[0003] By way of example, Document EP 1 672 270 in the name of the Applicant describes a turbopump in accordance with the precharacterizing portion of claim 1 .
[0004] The turbine drives the pump (or more precisely the rotor portion of the pump) at speeds that can be very high and can reach several thousands of revolutions per minute. Consequently, the component elements of the turbopump are subjected to high levels of stress and of vibration. In certain circumstances, the frequencies of such vibration can correspond to resonant modes of certain elements of the turbopump, and in particular of certain parts of the turbine, which can lead to the parts concerned being damaged. Such vibration has a negative impact on the operation of the turbopump and on its lifetime.
[0005] In particular, it has been observed that high levels of vibration affect the upstream parts of the turbine (first disk of the turbine that is close to the pump). If this vibration is not damped sufficiently, the vibratory phenomenon can become large, thereby leading to significant damage to the first disk of the turbine, or indeed to destruction of the turbine.
OBJECT AND SUMMARY OF THE INVENTION
[0006] The invention seeks to limit the vibration that occurs in the turbopump, in particular the vibration that affects the upstream parts of the turbine, i.e. the parts close to the pump.
[0007] This object is achieved by the fact that the above-mentioned turbopump includes a bleed-and-injection circuit comprising bleed means for bleeding the liquid fluid at the outlet from the pump, heater means for heating the liquid fluid as bled off in this way so as to transform it into gaseous fluid, and injector means for injecting the gaseous fluid into an interface region of the turbopump situated between the pump and the turbine.
[0008] Research has made it possible to have better understanding of the origin of the vibration affecting the upstream parts of the turbine. To clarify the explanations below, it is assumed that these upstream parts are constituted mainly by the first disk of the turbine.
[0009] Even if particular care is given to the connection between the pump and the turbine, in particular in terms of sealing, small leaks of the pumped liquid fluid occur, such that small quantities of the liquid fluid coming from the pump penetrate into the upstream portion of the casing of the turbine, in particular in the region of the first disk of the turbine.
[0010] Interaction has been revealed between this fluid coming from the pump and the first disk of the turbine. Energetic coupling occurs between this fluid coming from the pump, in which pressure pulses develop, and the first disk that starts vibrating at one of its resonant frequencies under the effect of these pressure pulses. In the absence of sufficient damping, this vibratory phenomenon can become large, thereby leading to significant damage of the disk or even to destruction of the turbine. The invention enables this vibration to be limited, thereby avoiding damage to the turbine.
[0011] Tests have shown that by modifying the thermodynamic conditions (flow rate, temperature) of the fluid coming from the pump and entering into the upstream portion of the pump casing, it is possible to reduce the amplitude of the vibratory phenomenon.
[0012] The inventors have had the idea of bleeding the liquid fluid at the outlet from the pump and of deliberately injecting it into the interface between the pump and the turbine after heating it. Thus, the bled-off and heated liquid fluid is injected in gaseous form into the interface between the pump and the turbine so as to mix in this location with the leakage liquid fluid, thereby causing a hotter fluid to enter into the turbine casing, thus having the effect of significantly reducing or even eliminating the phenomenon of interaction between the fluid coming from the pump and the first disk of the turbine that leads to vibration in the first disk of the turbine, as mentioned above.
[0013] The invention applies not only when the propellant is a cryogenic propellant, but also when the propellant is non-cryogenic. Either way, changing the temperature of the leakage fluid as a result of being mixed with the heated fluid modifies the thermodynamic conditions of the fluid in the desired direction.
[0014] Advantageously, the gaseous fluid is injected via a dynamic sealing system that is located in the interface region situated between the pump and the turbine.
[0015] The sealing system needs to be dynamic since it is mounted on a rotary shaft—the shaft that is common to the turbine and to the pump—in order to provide sealing between a hot environment in which the fluid is gaseous (turbine end) and the cryogenic environment in which the fluid is liquid (pump end).
[0016] The dynamic sealing system is situated in the interface region between the pump and the turbine.
[0017] The rotor of the pump is driven in rotation by the turbine so as to pump the propellant for injection into the combustion chamber of a rocket engine. In the context of the invention, and as often happens in the field of space propulsion, the fluid used as cryogenic propellant is liquid hydrogen.
[0018] Thus, advantageously, the turbine is fed with hot gas and the pump is fed with liquid hydrogen.
[0019] Advantageously, the bleed-and-injection circuit includes a bleed pipe extending from the outlet from the pump to the inlet of a heat exchanger co-operating with the exhaust pipe, and an injection pipe extending from the outlet of the heat exchanger to the interface region, in particular from the outlet of the heat exchanger to the dynamic sealing system.
[0020] Advantageously, the heat exchanger comprises a fluid flow chamber with a wall situated in the hot gas exhaust pipe.
[0021] For the purpose of heating the bled-off liquid, this makes it possible to use heat energy that is already available in the hot gas exhausted by the turbopump.
[0022] Advantageously, the flow chamber is coil shaped.
[0023] A coil provides a large contact surface area with the hot gas exhausted into the pipe in which the coil is situated.
[0024] Advantageously, the bleed-and-injection circuit includes means for controlling the flow of the liquid fluid in the bleed pipe.
[0025] To perform this control, which may be in the form of regulating pressure and/or flow rate in a manner defined by testing, the quantity of fluid that is bled off is a quantity that is necessary and sufficient for obtaining the desired reduction in vibration.
[0026] Advantageously, the means for controlling the flow of liquid fluid in the bleed pipe comprise means for adjusting the fluid pressure.
[0027] Advantageously, the bleed-and-injection circuit includes a bypass pipe for bypassing the heat exchanger between the bleed pipe and the injection pipe, and means for sharing the liquid fluid between the bypass pipe and the heat exchanger.
[0028] It is particularly advantageous to control the temperature of the gaseous fluid that is injected into the interface region between the pump and the turbine. This control over the temperature of the gaseous fluid is provided by the bypass pipe. The bypass pipe makes it possible to tap off liquid propellant prior to being injected into the heat exchanger in order to reinject it into the outlet from the heat exchanger, thereby causing it to be mixed with the fluid that has been vaporized in the heat exchanger and of temperature, if it is too high, that is lowered on coming into contact with the liquid fluid.
[0029] Advantageously, the means for sharing the liquid fluid comprises an adjustable constriction on at least one of the elements constituted by the bypass pipe and a segment of the bleed pipe that extends between the bypass pipe and the heat exchanger.
[0030] The adjustable constriction makes it possible to adapt the quantity of liquid fluid that is transformed into gaseous fluid at the outlet from the heat exchanger, and thus to control the temperature of the gaseous fluid that results from mixing between the gaseous fluid coming from the heat exchanger and the liquid fluid coming from the bypass pipe, which mixture is then injected into the dynamic sealing system; this is done while taking account of the temperature of the hot gas in the exhaust pipe and of the capacity of the heat exchanger.
[0031] Advantageously, the bleed-and-injection circuit includes means for adjusting flow rate in the injection pipe.
[0032] Advantageously, the turbopump includes a helium feed circuit for injecting helium into at least one of the elements constituted by the pump and by the turbine, with helium injection advantageously taking place via the dynamic sealing system.
[0033] The helium flow circuit serves to provide sealing between the pump while cooling down the engine and the turbopump prior to igniting the engine. By means of the above-described provision, advantage is taken of a portion of this circuit for the purpose of injecting the anti-vibration gaseous fluid.
[0034] The use of this pre-existing helium flow system presents the advantage of avoiding any need to incorporate an additional flow system for passing the flow of gaseous fluid and then for injecting it into the interface region of the turbopump situated between the pump and the turbine, with injection taking place in particular via the dynamic sealing system.
BRIEF DESCRIPTION OF THE DRAWINGS
[0035] Other characteristics and advantages of the invention appear on reading the following description of a preferred embodiment of the invention, given by way of example and with reference to the accompanying drawings.
[0036] FIG. 1 is a section view showing a conventional turbopump (shown in simplified manner to facilitate understanding the invention).
[0037] FIG. 2 is a section view of the same turbopump provided with the fluid recirculation system in an embodiment of the invention.
[0038] FIG. 3 is a detail view of the interface region between the pump and the turbine of the turbopump, shown in the zone into which, in accordance with the invention, the gaseous fluid coming from the fluid that has been bled off is injected.
[0039] FIG. 4 is a diagrammatic view of a heat exchanger in an embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0040] FIG. 1 is a simplified view of a turbopump 10 comprising at least a pump 14 and a turbine 12 connected together by a common rotary shaft 13 , 13 ′. This type of turbopump 10 is used in particular in liquid-propellant rocket engines in order to bring the propellants up to the pressure at which the propellants are injected into a combustion chamber of such an engine. In very diagrammatic manner, there can be seen the rotor 14 a of the pump 14 and the rotary disk 12 a of the turbine 12 . Reference 1 designates the casing of the turbopump, which includes a pump casing portion and a turbine casing portion.
[0041] Rotation of the turbine 12 causes the shaft 13 , 13 ′ to rotate, thereby driving the rotor of the pump 14 in rotation for the purpose of pumping a liquid from a feed 22 . By way of example, the turbine 12 is driven by a gas generator on board the rocket engine. This applies to turbopumps in which the turbine is actuated by the expansion of hot gas 20 generated by the gas generator.
[0042] Nevertheless, the turbine 12 of this type of turbopump could also be an expander cycle turbine. This applies to turbopumps in which the turbine is driven by the expansion of a propellant in the gaseous state after it has been heated via the wall of the combustion chamber.
[0043] The hot gas 20 that has driven the turbine 12 in rotation is exhausted via a hot gas exhaust pipe 16 . The hot gas that drives rotation of the turbine may for example be gaseous hydrogen (expander cycle) or a mixture of gaseous hydrogen and steam (gas generator cycle).
[0044] By way of example, the pumped liquid fluid may be a propellant, and in particular liquid hydrogen, that the pump 14 raises to pressure at its outlet 21 for the purpose of injecting the propellant into a combustion chamber of an engine (not shown) associated with the turbopump.
[0045] The hot and gaseous environment of the turbine 12 is sealed from the cryogenic and liquid environment of the pump 14 by a dynamic sealing system 18 that co-operates firstly with the shaft 13 , 13 and secondly with the casing 1 of the turbopump. In spite of this sealing, a small leak of liquid hydrogen is liable to flow from the pump environment 14 to the turbine environment 12 , as represented by arrows f. This leakage liquid reaches the turbine casing portion upstream from the first disk of the turbine. It thus becomes mixed, in a zone Z marked in FIG. 1 , with the hot gas leaving the upstream cavity 1 A of the turbine.
[0046] Bearings 13 A and 13 ′A support the shaft 13 , 13 in rotation relative to the casing 1 of the turbopump.
[0047] There follows a description of an embodiment of the invention, with reference to FIG. 2 .
[0048] In the description below, reference is made, by way of example, to using a hot gas mixture of hydrogen and steam as the fluid flowing through the turbopump for rotating the turbine, and to using hydrogen in liquid form as the liquid fluid being pumped. Nevertheless, other types of fluid could be envisaged, e.g. depending on the type of propellant concerned.
[0049] In the invention, and as shown in FIG. 2 , a bleed-and-injection circuit C is added to the FIG. 1 turbopump. This circuit has bleed means 30 that in the embodiment shown comprise a bleed pipe 30 bleeding liquid hydrogen at the outlet 21 from the pump 14 . This liquid hydrogen is at a high outlet pressure, e.g. about 185 bars. The fluid bled through this bleed pipe 30 then reaches the inlet 32 of a heat exchanger 34 , while it is still in liquid form, and it leaves the heat exchanger at 36 in gaseous form. The outlet 36 from the heat exchanger 34 is connected to an injection pipe 50 that leads into the dynamic sealing system 18 situated at the interface between the pump 14 and the turbine 12 . Specifically, the dynamic sealing system has two gaskets that are axially spaced apart in the longitudinal direction of the shafts 13 , 13 ′, and injection takes place between these two gaskets.
[0050] Specifically, the heat exchanger 34 co-operates with the hot gas exhaust pipe 16 so as to enable it to be heated by the gas coming from the turbine exhaust. More precisely, the heat exchanger 34 is situated in a segment of the pipe 16 .
[0051] The temperature of the liquid hydrogen at the net to the heat exchanger may for example be about 40 K. At the outlet from the heat exchanger 36 , the hydrogen is gaseous as a result of being heated in the heat exchanger.
[0052] In the example shown, pressure regulator means 38 are situated on the liquid hydrogen bleed pipe 30 . The pressure regulator means 38 , e.g. a constriction of variable section, serves to reduce the pressure of the liquid hydrogen flowing in the pipe 30 , e.g. to take it to a pressure of about 110 bars downstream from the constriction.
[0053] Provision could be made for all of the liquid hydrogen downstream from the pressure regulator means 38 to reach the inlet of the heat exchanger. Nevertheless, in the example shown, a bypass pipe 40 serves to bypass the heat exchanger 34 so that a portion of the fluid that has been bled off can pass directly from the bleed type 30 to the injection pipe 50 . Under such circumstances, only a portion of the liquid hydrogen at low pressure is injected into the heat exchanger 34 in order to be heated, while the remaining portion passes directly into the injection pipe 50 without being heated. It can be understood that the relative proportions of heated hydrogen and of non-heated hydrogen determine the temperature of the gaseous fluid that results from mixing them together and that is injected into the region of the dynamic sealing system 18 .
[0054] In order to adjust these proportions, the fluid bleed and injection circuit has means for sharing the liquid hydrogen between the heat exchanger and the bypass pipe. These means may comprise flow sharing means between the bypass pipe 40 and the segment 31 of the bleed pipe 30 that extends between the bypass pipe 40 and the inlet 32 of the heat exchanger. They may merely comprise a flow rate limiter situated on the bypass pipe 40 or on the segment 31 . In the example shown, flow rate adjustment means 39 of the adjustable section constriction type are provided on the segment 31 , and flow rate adjustment means 42 of adjustable section constriction type are provided on the bypass pipe 40 .
[0055] The adjustable constriction 38 serves to adjust the pressure at the inlet to the heater device. The constrictions 39 and 42 serve to adjust the proportion of the fluid that is heated and vaporized in the heat exchanger compared with the proportion that remains liquid and cold, thus making it possible to adjust the temperature of the fluid injected by the pipe 50 , e.g. in order to obtain a temperature of about 300 K. Under all circumstances, the proportions are such that the fluid leaving the pipe 50 is in gaseous form.
[0056] In the example shown, the injection pipe 50 also has means 44 for adjusting the rate at which gaseous hydrogen is injected, e.g. a constriction of adjustable section. These adjustment means are situated in the downstream portion of the pipe 50 , downstream from the connection node 43 between the bypass pipe 40 and the outlet from the heat exchanger. By way of example, this ensures that the gaseous hydrogen is injected into the dynamic sealing system 18 at a flow rate of about 7 grams per second (g/s).
[0057] FIG. 3 shows the dynamic sealing system 18 in detail.
[0058] This figure is a diagram showing the location of the end 50 A of the injection pipe 50 as described above with reference to FIG. 2 . As can be seen, this end 50 A leads into the region of the dynamic sealing system 18 in order to inject gaseous hydrogen into that location. More particularly, the injection at the outlet from the end 50 A takes place at a location referred to as the “inter-ring” location 52 of the dynamic sealing system 18 . This inter-ring location 52 is situated between two sealing gaskets, respectively referenced 55 and 55 ′, that are held by two flanges, respectively referenced 51 and 51 ′, and by a spacer 53 . The gaseous hydrogen from the injection pipe 50 is injected between the two gaskets 55 and 55 ′ via holes 53 ′ that are pierced radially through the spacer 53 .
[0059] A small leakage flow of liquid hydrogen 54 comes from the environment of the pump and flows towards the environment of the turbine.
[0060] This small flow of liquid hydrogen 54 is vaporized as it comes into contact with the gaseous hydrogen. Thus, all of the leakage fluid is vaporized.
[0061] The mixing between the leakage liquid fluid and the gaseous fluid injected into the inter-ring location 52 takes place in the downstream region of the inter-ring location 52 , where “downstream” is in the flow direction of the gaseous fluid injected by the pipe 50 . Specifically, mixing takes place in the gaps between the spacer 53 and the shafts 13 , 13 ′. The pressure at which the gaseous hydrogen is injected into the inter-ring location 52 is of the order of 35 bars, for example.
[0062] FIG. 4 is a diagrammatic view of the heat exchanger 34 situated in the hot gas exhaust pipe 16 . This heat exchanger 34 is preferably held by attachments 35 that withstand thermal expansion.
[0063] The heat exchanger 34 is in the form of a coil. It could have other shapes appropriate for a heat exchanger.
[0064] Nevertheless, and byway of example, when the heat exchanger 34 is in the form of a coil, it presents: a thickness of about 1 millimeter (mm), and it is helically wound so as to form a plurality of turns.
[0065] The temperature inside the hot gas exhaust pipe 16 usually lies in the range about 600 K to about 700 K.
[0066] The injection pipe 50 uses a portion of the helium flow circuit in the turbopump. In the example shown, the turbopump includes a helium feed connected to the dynamic sealing system 18 that provides sealing for the pump during the stage prior to igniting the engine that the turbopump 10 is to feed; this stage is known as the stage of cooling down the engine. No propellant leak between the pump 14 and the turbine 12 is acceptable during this stage.
[0067] As can be seen in FIG. 2 , the injection pipe 50 includes the terminal segment 67 of the pipe for feeding the dynamic sealing system with helium. Thus, a portion of the helium flow circuit is reused for making a portion of the bleed-and-injection circuit of the invention. It should be observed that the segment 67 includes a check valve 66 that is situated upstream from its connection to the injection pipe 50 so as to prevent hydrogen coming from the pipe 50 penetrating into the helium delivery circuit.
[0068] The gaseous hydrogen is introduced into the helium feed circuit of the turbopump 10 after its engine has been ignited, once the pressure at the outlet from the pump reaches a sufficient value. The gaseous helium and hydrogen thus coexist in the same circuit for a few seconds. Once this time has elapsed, only gaseous hydrogen flows in the segment 67 .
[0069] It should be observed that flexible portions may be provided on the above-described pipes (in particular the bleed pipe 30 and the injection pipe 50 ) in order to absorb relative movements between these pipes 30 and 50 within the turbopump 10 . | A turbopump includes a turbine fed with hot gas, a pump driven by the turbine and fed with liquid fluid, and a hot gas exhaust pipe situated downstream from the turbine. The turbopump includes a bleed-and-injection circuit including a bleeder for bleeding the liquid fluid at the outlet from the pump, a heater for heating the liquid fluid as bled off in this way so as to transform it into gaseous fluid, and an injector for injecting the gaseous fluid into an interface region of the turbopump situated between the pump and the turbine, so as to optimize the flow and temperature conditions of the fluid entering into the turbine cavity in order to eliminate the vibratory phenomena that result from interaction between the fluid and the turbine disk. | 5 |
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This is a non-provisional application based upon U.S. provisional patent application Ser. No. 60/649,778, entitled “A MODULAR PLUMBING METHOD FOR OFFICE FURNITURE”, filed Feb. 3, 2005.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to modular office furniture, and, more particularly, to modular office wall panels arranged in a work environment.
[0004] 2. Description of the Related Art
[0005] A typical work surface requires convenient access to electrical power. In an office setting, electrical power is typically provided in the form of electrical receptacles connected to a utility power source. The electrical receptacles power office equipment such as computers, calculators, facsimile machines, copiers, printers, clocks, lamps and the like. Work surfaces are conveniently arranged and can be connected to modular wall panels that are arranged in a removable fashion for use in an office environment. Work surfaces, particularly modular furniture work surfaces are easily configurable to meet the changing needs of the business. Work surfaces require access to electricity, and the existing circuits and receptacles in a building may limit the inherent flexibility of a modular furniture work surface by requiring the work surface to be located near existing circuits and receptacles.
[0006] A fuel cell is an electrochemical energy conversion device that converts hydrogen or some other compound of gases through suitable conversion to hydrogen, and oxygen into water, producing electricity and heat in the process.
[0007] What is needed in the art is a system that does not require connection to a utility power grid, is cost effective to operate, is suitable for typical work environments and is environmentally friendly.
SUMMARY OF THE INVENTION
[0008] The present invention provides a work surface gas delivery system to power a fuel cell module.
[0009] The invention comprises, in one form thereof, a modular wall panel assembly including a wall panel and a plumbing system installed at least partially within the wall panel.
[0010] An advantage of the present invention is that it provides a reconfigurable distribution system for a gas supply.
[0011] Another advantage of the present invention is that it provides an electrical power module that is connectable to a wall panel system.
[0012] Yet another advantage of the present invention is that it removes the restriction of having to position work surfaces proximate to an electrical outlet to obtain power.
[0013] A further advantage of the present invention is that it removes a restriction of having to hardwire modular office panels into a building power grid.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention will be better understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawings, wherein:
[0015] FIG. 1 is a perspective, partially fragmentary view of an embodiment of modular furniture wall panels of the present invention including a plumbing system of the present invention;
[0016] FIG. 2 is another perspective view of the modular furniture wall panel plumbing system of FIG. 1 interconnected with a fuel cell;
[0017] FIG. 3 is a schematicized top view of the modular wall panel system of FIGS. 1 and 2 ; and
[0018] FIG. 4 is a fragmentary perspective view of an end of a modular wall panel of FIGS. 1-3 .
[0019] Corresponding reference characters indicate corresponding parts throughout the several views. The exemplification set out herein illustrates one preferred embodiment of the invention, in one form, and such exemplification is not to be construed as limiting the scope of the invention in any manner.
DETAILED DESCRIPTION OF THE INVENTION
[0020] Referring now to the drawings, and more particularly to FIGS. 1 and 2 , there is shown a workspace in an office environment including modular wall panel system 10 generally having at least one modular wall panel 12 , which is associated with another modular wall panel 14 . Work surface 16 is attached to modular wall panel 14 and provides a functional work surface area. A plurality of modular wall panels 12 and 14 can be interconnected and all panels 12 or 14 , or any subset thereof can have at least one work surface 16 attached therewith. Modular wall panels 12 and 14 are substantially similar and any reference to modular wall panel 14 should be understood to be typical of other interconnected modular wall panels including wall panel 12 .
[0021] Now, additionally referring to FIG. 3 , modular wall panel 14 includes a raceway 18 , a cavity 20 , supply pipes 22 , 24 and 26 , and drain pipes 28 , 30 and 32 . Although supply pipes and drain pipes are illustrated as being separated, the two can be associated and somewhat interconnected to further coordinate their interconnection. Supply pipes 22 , 24 and 26 supply a hydrogen compound, or hydrogen gas throughout modular wall system 10 .
[0022] A drain pipe 32 is shown in raceway 18 allowing a drain line to run along a lower portion of wall panel 14 and interconnect at the ends thereof with other wall panels. At some point along the running of drain pipe 32 a T-coupling 42 is supplied that interconnects a drain pipe 30 , having a predetermined installation length, which interconnects a drain pipe 28 with drain pipe 32 allowing fluid to further drain through floor drain coupling 34 . Various plumbing fixtures, such as a three-way coupling 40 connects a drain pipe 28 in modular panel 14 and another drain pipe in modular wall panel 12 with drain pipe 30 to cause fluid therein to drain towards floor drain coupling 34 . Floor drain coupling 34 may be a flexible tube that is connected to an end of T-coupling 42 and a floor drain. Hydrogen is supplied by a source, not shown, and is distributed by way of supply pipes 22 , 24 and 26 , which may be coupled together such as by an elbow coupling 38 as shown in FIG. 1 . Respectively fluidly coupled to supply pipe 22 and drain pipe 28 are supply valve 44 and drain valve 46 . Valves 44 and 46 respectively shut off the contents of the pipes from the ambient environment, such as that at or above a work surface 16 .
[0023] Now, additionally referring to FIG. 4 , there is shown an end of wall panel 14 with a supply pipe 22 extending therefrom. For purposes of illustration a coupling 36 is shown to interconnect with an end of supply pipe 22 so as to fluidly couple one wall panel with another wall panel, or with a gas source or drain as appropriate. Although the illustration relates to supply pipe and coupling, a similar arrangement for the drain pipes is also provided. It should also be understood that although the supply pipes and drain pipes are, for purposes of illustration, shown as being similar, the actual size, color and/or cross-sectional shape can be different to avoid an inadvertent mixing of supply and drain plumbing.
[0024] As shown in FIG. 3 , a plurality of wall panels are positioned and are plumbed with couplings, such as couplings 36 and T-coupling 42 . Supply lines 22 , 24 and 26 are of a predetermined length and are either integrally constrained and contained in a respective wall panel or are replaceably therein, such as being within a cavity 20 of a wall panel 14 . Couplings such as coupling 36 , elbow coupling 38 , three-way coupling 40 and T-couplings 42 may be removably placed on ends of respective pipes or may be attached requiring a destructive method for their removal.
[0025] A fuel cell 48 is fluidly coupled to a supply pipe 22 and a drain pipe 28 to provide a supply of hydrogen to fuel cell 48 and a drain line for the draining away of water created in the combining of hydrogen with atmospheric oxygen to produce electricity. Fuel cell 48 includes a supply line with coupling 50 , a drain line with coupling 52 and a plurality of electrical outlets 54 . For the purposes of clarity fuel cell 48 is shown positioned on work surface 16 although fuel cell 48 may be integral with wall panel 14 with receptacles 54 remotely located therefrom. Fuel cell 48 is fluidly coupled by way of lines 50 and 52 each with couplings respectively to pipe 22 and pipe 28 . As hydrogen is supplied, oxygen from the atmosphere is consumed by the fuel cell reaction, thereby providing electrical energy at outlets 54 .
[0026] Advantageously the present invention provides fluid coupling of at least one plumbing system in modular wall panel furniture. The fluid coupling provides for the delivery of hydrogen to a fuel cell and the draining of the water created by the reaction therein.
[0027] While this invention has been described as having a preferred design, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims. | A modular wall panel assembly including at least one wall panel and a plumbing system installed at least partially within the at least one wall panel. | 4 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to an apparatus for liquid treatment of disc-shaped articles, and to a heating system for use in such an apparatus.
2. Description of Related Art
Liquid treatment includes both wet etching and wet cleaning, wherein the surface area of a wafer to be treated is wetted with a treatment liquid and a layer of the wafer is thereby removed or impurities are thereby carried off. A device for liquid treatment is described in U.S. Pat. No. 4,903,717. In this device the distribution of the liquid may be assisted by the rotational motion imparted to the wafer.
Techniques for processing a surface of a disc-shaped article are typically used in the semiconductor industry on silicon wafers, for example of 300 mm or 450 mm diameter. However, such techniques may be applied for other plate-like articles such as compact discs, photo masks, reticles, magnetic discs or flat panel displays. When used in semiconductor industry they may also be applied for glass substrates (e.g. in silicon-on-insulator processes), III-V substrates (e.g. GaAs) or any other substrate or carrier used for producing integrated circuits.
When using heated process liquids, there is a problem in achieving temperature uniformity across the surface of the wafer, and the need to address that problem becomes more acute as wafer diameters increase.
In particular, as the wafer diameter increases, so too will the temperature differential between a liquid at the point where it is applied in a central region of the wafer and the same liquid after it has travelled radially outwardly to the periphery of the wafer. This results in varied etch rates as a function of the distance from the center of the wafer, and hence poor process uniformity.
Conventional approaches to alleviate this problem have included dispensing process liquid from movable arms, so-called “boom swing” dispensers; however, this involves an increase in the cost and complexity of the device as well as its operation. The problem can be addressed to some extent by increasing the flow of process liquid, and/or by dispensing a high temperature liquid such as deionized water on the opposite side of the wafer; however, these techniques result in higher consumption of process liquids.
Commonly-owned co-pending application U.S Patent Application Pub. No. 2013/0061873 describes improved apparatus equipped with an infrared heater for heating a wafer to enhance process uniformity. Although the devices of that patent application represent an improvement over conventional techniques, there remains a need to provide further enhanced process uniformity and control.
SUMMARY OF THE INVENTION
Thus, in one aspect, the present invention relates to an apparatus for treating a disc-shaped article, comprising a spin chuck for holding a disc-shaped article in a predetermined orientation relative to an upper surface of the spin chuck, and at least three individually controllable infrared heating elements mounted above the upper surface of the spin chuck and below a disc-shaped article when mounted on the spin chuck. The infrared heating elements are mounted in a stationary manner with respect to rotation of the spin chuck. The at least three individually controllable infrared heating elements are arranged in a nested configuration so as to define individually controllable inner, middle and outer heating zones adjacent a disc-shaped article when positioned on the spin chuck.
In preferred embodiments of the apparatus according to the present invention, each of the heating elements has at least one of a shape and a position such that each of the heating elements heats regions of differing distance from the axis of rotation of the spin chuck.
In preferred embodiments of the apparatus according to the present invention, each of the heating elements comprises a curved portion that extends generally along an arc of a circle that is eccentric to the axis of rotation of the spin chuck.
In preferred embodiments of the apparatus according to the present invention, each of the heating elements comprises two curved portions interconnected by a straight portion, such that each of the heating elements is generally C-shaped.
In preferred embodiments of the apparatus according to the present invention, a first one of the two curved portions extends generally along an arc of a first circle and a second one of the two curved portions extends generally along an arc of a second circle, the first and second circle having centers that are offset from one another.
In preferred embodiments of the apparatus according to the present invention, each of the two curved portions extends generally along an arc of a same circle.
In preferred embodiments of the apparatus according to the present invention, each the heating element comprises two straight portions interconnected by a curved portion.
In preferred embodiments of the apparatus according to the present invention, the two straight portions are parallel to one another.
In preferred embodiments of the apparatus according to the present invention, each of the heating elements comprises a curved portion extending along an arc of a circle, and wherein the circle for each heating element is concentric with the circle for at least two others of the heating elements.
In preferred embodiments of the apparatus according to the present invention, a circle circumscribing emitting portions of any one of the at least three individually controllable infrared heating elements does not intersect a circle circumscribing emitting portions of any others of the at least three individually controllable infrared heating elements.
In preferred embodiments of the apparatus according to the present invention, the apparatus includes a plate that is transparent to infrared radiation emitted by the at least three individually controllable infrared heating elements, said plate being positioned between said at least three individually controllable infrared heating elements and a disc-shaped article when positioned on the spin chuck.
In preferred embodiments of the apparatus according to the present invention, the plate is part of a housing that surrounds the at least three individually controllable infrared heating elements.
In preferred embodiments of the apparatus according to the present invention, the housing is mounted in a stationary manner with respect to rotation of the spin chuck.
In another aspect, the present invention relates to an infrared heating assembly for use in an apparatus for treating a disc-shaped article. The infrared heating assembly comprises at least three individually controllable infrared heating elements mounted in a common frame connector. The at least three individually controllable infrared heating elements are arranged in a nested configuration so as to define individually controllable inner, middle and outer heating zones. Each of the heating elements has at least one of a shape and a position such that each of the heating elements extends over regions of differing distance from the center of a circle circumscribing the infrared heating assembly.
In preferred embodiments of the infrared heating assembly according to the present invention, each of the at least three individually controllable infrared heating elements comprises at least one curved portion and at least one straight portion.
In preferred embodiments of the infrared heating assembly according to the present invention, the curved portions of adjacent infrared heating elements extend along concentric circles and the straight portions of adjacent heating elements are parallel to one another.
In preferred embodiments of the infrared heating assembly according to the present invention, the common frame connector comprises a plurality of electrical connectors equal in number to the at least three individually controllable infrared heating elements, thereby to permit individual connection of each of the at least three individually controllable infrared heating elements to a controller for individually energizing each of the at least three individually controllable infrared heating elements.
In preferred embodiments of the infrared heating assembly according to the present invention, the assembly includes a housing surrounding the at least three individually controllable infrared heating elements, the housing comprising a plate forming an upper portion thereof, the plate being transparent to the infrared radiation emitted by the at least three individually controllable infrared heating elements.
In yet another aspect, the present invention the present invention relates to an infrared lamp for use in heating a disc-shaped workpiece in such a way that the infrared lamp radiates light onto the disc-shaped workpiece while the infrared lamp and the disc-shaped workpiece rotate relative to each other. The infrared lamp comprises an arc-shaped emitting part generally describing a circle that is eccentric in relation to an axis of rotation of the disc-shaped workpiece, and an adjoining emitting part disposed inside the circle and extending from the arc-shaped emitting part generally along a chord of the circle.
In preferred embodiments of the infrared lamp for use in heating a disc-shaped workpiece according to the present invention, the adjoining emitting part has a linear shape.
In preferred embodiments of the infrared lamp for use in heating a disc-shaped workpiece according to the present invention, the lamp includes a second arc-shaped emitting part at an end of the adjoining emitting part opposite the arc-shaped emitting part.
In preferred embodiments of the infrared lamp for use in heating a disc-shaped workpiece according to the present invention, the adjoining emitting part is integrally connected to an end of the arc-shaped emitting part.
In preferred embodiments of the infrared lamp for use in heating a disc-shaped workpiece according to the present invention, the arc-shaped emitting part and the adjoining emitting part are integrally formed and each is round in cross-section.
In yet another aspect, the present invention relates to a heating apparatus comprising an infrared lamp positioned facing a disc-shaped workpiece, the heating apparatus heating the disc-shaped workpiece in such a way that the infrared lamp radiates light onto the disc-shaped workpiece while the infrared lamp and the disc-shaped workpiece rotate relative to each other. The infrared lamp comprises an arc-shaped emitting part generally describing a circle that is eccentric in relation to an axis of rotation of the disc-shaped workpiece, and an adjoining emitting part disposed inside the circle and extending from the arc-shaped emitting part generally along a chord of the circle. The heating apparatus comprises a plurality of the infrared lamps, wherein the arc-shaped emitting parts of the infrared lamps are positioned concentrically to one another.
In preferred embodiments of the heating apparatus according to the present invention, the adjoining emitting part of each of the infrared lamps does not intersect a circle circumscribing the arc-shaped emitting part of the corresponding adjacent inner infrared lamp.
In preferred embodiments of the heating apparatus according to the present invention, the infrared lamp further comprises a second arc-shaped emitting part at an end of the adjoining emitting part opposite the arc-shaped emitting part.
In preferred embodiments of the heating apparatus according to the present invention, ends of the arc-shaped emitting part and the second arc-shaped emitting part define an angle whose vertex is on an axis of rotation of the disc-shaped article.
In preferred embodiments of the heating apparatus according to the present invention, the adjoining emitting part of each of the infrared lamps is integrally connected to an end of the corresponding arc-shaped emitting part.
In preferred embodiments of the heating apparatus according to the present invention, the adjoining emitting part of each of the infrared lamps does not extend outwardly from the circle described by the corresponding arc-shaped emitting part.
BRIEF DESCRIPTION OF THE DRAWINGS
Other objects, features and advantages of the invention will become more apparent after reading the following detailed description of preferred embodiments of the invention, given with reference to the accompanying drawings, in which:
FIG. 1 is an exploded perspective view of an apparatus for treating disc-shaped articles according to an embodiment of the present invention;
FIG. 2 is top plan view of the embodiment of FIG. 1 ;
FIG. 3 is an axial section through the chuck depicted in FIGS. 1 and 2 , taken along the line III-III of FIG. 2 ;
FIG. 4 is a view similar to that of FIG. 2 , of another embodiment of an apparatus according to the present invention;
FIG. 5 is a view similar to that of FIG. 2 , of yet another embodiment of an apparatus according to the present invention;
FIG. 6 is a view similar to that of FIG. 2 , of still another embodiment of an apparatus according to the present invention;
FIG. 7 is an explanatory view for better understanding the relative shapes and sizes of the lamps utilized in the embodiment of FIG. 6 ;
FIG. 8 is a graph showing the depth of material etched when using the lamp assembly of the FIGS. 1-3 embodiment with all three IR lamps turned off;
FIG. 9 is a graph showing the depth of material etched when using the lamp assembly of the FIGS. 1-3 embodiment with all three IR lamps turned on;
FIG. 10 is a graph showing the depth of material etched when using the lamp assembly of the FIGS. 1-3 embodiment with the inner and middle IR lamps turned on and the outer IR lamp turned off; and
FIG. 11 is a graph showing the depth of material etched when using the lamp assembly of the FIGS. 1-3 embodiment with the inner and middle IR lamps turned off and the outer IR lamp turned on.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
Referring now to the drawings, FIGS. 1 and 2 depict an apparatus made up of two principal subassemblies, namely, a base spin chuck 10 and a modular infrared heating assembly 20 . The spin chuck 10 comprises a rotary main body 12 that is mounted for rotation about a stationary central hollow post 14 . This post 14 in turn comprises a central nozzle 18 for dispensing process liquid or gas onto the underside of a wafer when mounted on the spin chuck, as well a series of female electrical sockets 15 in a shoulder of the post 14 , which sockets receive corresponding male connectors (not shown) that depend downwardly from the heating assembly 20 , and which supply driving current to the IR heating lamps inside that assembly 20 .
The chuck body 12 has mounted therein a series of gripping pins 16 , which operate generally as described in the above-referenced U.S. Pat. No. 4,903,717, in that the pins 16 are driven in unison by a common ring gear between a radially outer open position and a radially inner closed position in with the upper ends of these pins engage the edge of a disc-shaped article to be treated.
The heating assembly 20 in this embodiment is formed as a modular unit comprising a lower dished housing or shell 22 that contains the IR lamps 21 , 23 , 25 . A cover 24 is screwed onto the lower housing 22 by a series of peripheral screws 26 , which are six in number in this embodiment.
The cover 24 in this embodiment is a plate formed from a material that is transparent to the wavelengths of IR radiation emitted by the lamps 21 , 23 , 25 , and this plate 24 may be formed for example of sapphire or quartz glass, as is known to those skilled in this art. The plate 24 has a small central opening 19 formed therein, to permit passage of the upper end of dispensing nozzle 18 .
Within the housing of the heating assembly 20 , that is, inside the lower housing 22 and beneath the transparent plate 24 , there is mounted a set of three infrared heating lamps 21 , 23 , 25 , which are carried by a common frame 29 that also incorporates the associated electrical supply wiring (not shown). The assembly formed by the housing formed of lower shell 22 and upper plate 24 , frame 29 and lamps 21 , 23 , 25 in this embodiment is rigidly mounted to the stationary post 14 .
Referring now to FIG. 2 , it can be seen that the wafer W is now supported by the ends of pins 16 projecting adjacent the outer periphery of the heating assembly 20 . The phantom line in FIGS. 2 and 3 designates the position of a wafer W when held by the apparatus, with the underside of wafer W being spaced by a small defined gap from the cover 24 .
The wafer W is centered above the heating assembly 20 , which in turn is centered on the axis of rotation of the underlying spin chuck. It will be appreciated that the spin chuck 10 is therefore designed to hold a wafer W of a specified diameter. In the embodiments described herein, that diameter is 300 mm, which is a common diameter of silicon wafer at present. However, the apparatus may of course be designed to hold disc-shaped articles of other diameters, such as 200 mm and 450 mm.
In the plan view of FIG. 2 it can be seen that each of the three heating elements in this embodiment is made of two curved portions ( 25 - 1 and 25 - 3 in the case of the outer heating element 25 ) interconnected by a straight portion ( 25 - 2 in the case of the outer heating element 25 ). The middle and inner heating elements 23 and 21 , respectively, have the same shape. The heating elements 21 , 23 , 25 of this embodiment are thus generally C-shaped. Moreover, while the curved portions (e.g., 25 - 1 , 25 - 3 ) of these heating elements generally follow a circular arc, and while the adjacent curved portions of all three heating elements are preferably substantially concentric, the circles described by those curved portions are not in this embodiment concentric with the center of the heating assembly 20 and hence are not concentric with the axis of rotation of the spin chuck.
Consequently, in this embodiment, both the position and shape of the heating elements 21 , 23 , 25 is such that, as the wafer W is rotated by the chuck 10 relative to the stationary heating elements 21 , 23 , 25 , each heating element effectively “travels” radially relative to the rotating wafer W, in that each heating element heats an annular region whose radial extent is significant greater than the cross-sectional diameter of the heating elements. For the present embodiment, those zones are delimited by the circles shown in broken line in FIG. 2 , and those zones are designated Z 1 , Z 2 and Z 3 in FIG. 2 .
It will be appreciated that each heating element also contributes to some extent to the heating in the zone or zones adjacent thereto. The broken line circles in FIG. 2 thus delineate the position at which the predominant heating effect changes from one heating element to the next.
In FIG. 3 , it can be seen that the frame 29 is supported within the housing 22 , 24 , with the housing of the heating assembly 20 being in this embodiment rigidly secured to the stationary post 14 , and thus with the frame 29 and lamps 21 , 23 , 25 also being mounted in a stationary manner to the post 14 . The upwardly-facing surface of the lower housing part or shell 22 is preferably provided with a suitable IR reflective coating 31 , to aid in directing the IR radiation emitted by lamps 21 , 23 , 25 , upwardly through the transparent plate 24 and onto the downwardly facing surface of the wafer W.
The stationary post 14 is mounted onto the frame 32 of the apparatus, which in this embodiment also carries a stator 34 . Stator 34 in turn drives rotor 36 , which is attached to the body 12 of spin chuck 10 . Also visible in FIG. 3 is the ring gear 11 mentioned above, which drives the gripping pins 16 in unison.
It will be appreciated that in the embodiments described herein, the entire heating assembly is mounted in a stationary manner on the post 14 , as is described for example in connection with the heating assembly disclosed in commonly-owned co-pending application U.S Patent Application Pub. No. 2013/0061873.
FIG. 4 depicts another embodiment, in which the infrared lamps 21 ′, 23 ′, 25 ′ are shaped differently than in the preceding embodiments. In particular, each lamp comprises two straight portions 21 - 1 ′, 21 - 3 ′, 23 - 1 ′, 23 - 3 ′, 25 - 1 ′, 25 - 3 ′, and one straight portion 21 - 2 ′, 23 - 2 ′, 25 - 2 ′. The shape and position of the straight portions of these elements contribute to the creation of heating zones as described in connection with the preceding embodiments.
FIG. 5 depicts yet another embodiment, in which each of the three heating elements 41 , 43 , 45 is a continuous curved tubular element. Moreover, while these heating elements generally follow a circular arc, and while all three heating elements are preferably substantially concentric, the circles described by those heating elements are not in this embodiment concentric with the center of the heating assembly 20 and hence are not concentric with the axis of rotation of the spin chuck.
Consequently, in this embodiment, both the position and shape of the heating elements 41 , 43 , 45 is such that, as the wafer W is rotated by the chuck 10 relative to the stationary heating elements 41 , 43 , 45 , each heating element also heats an annular region whose radial extent is significant greater than the cross-sectional diameter of the heating elements, as in the preceding embodiments.
FIGS. 6 and 7 illustrate a still further approach to the design of the heating lamps. In this embodiment, four individually controllable IR heating lamps 51 , 53 , 55 , 57 are mounted on a suitable carrier frame 59 in the manner as generally as described in connection with the preceding embodiments. The housing 20 and spin chuck 10 are as previously described.
The conceptual diagram of FIG. 7 reveals the interrelationship between the shapes and sizes of these lamps 51 , 53 , 55 , 57 . In particular, the outer periphery of the curved part of lamp 53 describes a circle R 1 that is also coincident with the inner periphery of the curved part of lamp 51 . Similarly, the outer periphery of the curved part of lamp 55 describes a circle R 2 that is also coincident with the inner periphery of the curved part of lamp 53 , and the outer periphery of the curved part of lamp 57 describes a circle R 3 that is also coincident with the inner periphery of the curved part of lamp 55 . Furthermore, the outer periphery of the largest lamp 51 approximately coincides with a one-fourth quadrant of the circular housing 20 .
Therefore, when the lamps 51 , 53 , 55 , 57 are mounted as shown in FIG. 6 , there are effectively no gaps in the heated regions of the wafer W, as the wafer is rotated in relation to the stationary lamps.
It is to be noted that the heating lamps in each of the preceding embodiments are preferably individually controllable. It is particularly preferred that each lamp can be not only switched on and off independently of the others, but also that the wattage to each lamp can be independently varied. This permits a variety of advantageous process control.
For example, FIG. 8 shows, for purposes of comparison, etching profiles achieved when using the heating lamp assembly of FIGS. 1-3 but without powering any of the three IR lamps 21 , 23 , 25 . As can be seen, there is a markedly greater removal of material from the wafer in the central region of the wafer as compared to the peripheral region. This is because etchant dispensed centrally of the wafer has cooled substantially as it travels radially outwardly across a 300 mm diameter wafer. Moreover, this undesired etching profile is largely the same regardless of whether the etching chemistry, temperature and flow are selected to etch 4 Å or material or 9 Å of material. In either case, the material removed at the outer periphery of the wafer is less by about 2Å.
By contrast, FIG. 9 shows etching profiles achieved by appropriately powering all three of the lamps 21 , 23 , 25 . The etching profiles have been nearly inverted relative to those of FIG. 8 . It should be noted also that these profiles are attained at lower flow rates and shorter processing times than for the data of FIG. 8 . It should also be noted that for many process specifications, the ideal etching profile is not necessarily flat; instead, as in FIG. 9 , a desired etching profile will often call for “overetching” of the peripheral wafer region, e.g., removing approximately 10% more material at the wafer edge than at the wafer center. As can be seen in FIG. 9 , the apparatus and heating assemblies of the present invention are particularly well-suited to such applications.
FIG. 10 shows the profile attained when only the lamps 21 , 23 are powered, whereas FIG. 11 shows the profile attained when only the lamp 25 is powered. In neither case does the resulting profile resemble those of FIG. 9 .
While the present invention has been described in connection with various preferred embodiments thereof, it is to be understood that those embodiments are provided merely to illustrate the invention, and should not be used as a pretext to limit the scope of protection conferred by the true scope and spirit of the appended claims. | An apparatus for treating a disc-shaped article comprises a spin chuck and at least three individually controllable infrared heating elements. The infrared heating elements are mounted in a stationary manner with respect to rotation of said spin chuck. The infrared heating elements are arranged in a nested configuration so as to define individually controllable inner, middle and outer heating zones adjacent a disc-shaped article when positioned on the spin chuck. | 5 |
FIELD OF THE INVENTION
The present invention generally concerns interrogators for use with electronics assemblies that transmit information related to identification variables and/or measurements of selected physical or environmental conditions. More particularly, the subject calibration methodology utilizes a transmitter and receiver pair to evaluate sensed transmitter power. In an alternative embodiment, paired interrogator transceivers in a symmetrical arrangement yield self-evaluating devices for relaying digital data as well as sensed parameter information.
BACKGROUND OF THE INVENTION
The incorporation of electronic devices with pneumatic tire and wheel structures yields many practical advantages. Tire electronics may include sensors and other components for relaying tire identification parameters and also for obtaining information regarding various physical parameters of a tire, such as temperature, pressure, tread wear, number of tire revolutions, vehicle speed, etc. Such performance information may become useful in tire monitoring and warning systems, and may even potentially be employed with feedback systems to regulate proper tire parameters.
Yet another potential capability offered by electronics systems integrated with tire structures corresponds to asset tracking and performance characterization for commercial vehicular applications. Commercial truck fleets, aviation craft and earth mover/mining vehicles are all viable industries that could utilize the benefits of tire electronic systems and related information transmission. Radio frequency identification (RFID) tags can be utilized to provide unique identification for a given tire, enabling tracking abilities for a tire. Tire sensors can determine the distance each tire in a vehicle has traveled and thus aid in maintenance planning for such commercial systems. Vehicle location and performance can be optimized for more expensive applications such as those concerning earth-mining equipment.
One particular type of sensor, or condition-responsive device, that has recently become desirable for use in certain tire electronics systems to determine various parameters related to a tire or wheel assembly is an acoustic wave device, such as a surface acoustic wave (SAW) device. SAW devices have desirable properties for certain sensor applications since they are sensitive, use very little power, and can be operated at RF frequencies convenient for relaying information in a wireless fashion. SAW devices may include at least one resonator element made up of interdigitated electrodes deposited on a piezoelectric substrate.
When an electrical input signal is applied to a SAW device, selected electrodes cause the SAW to act as a transducer, thus converting the input signal to a mechanical wave in the substrate. Other structures in the SAW reflect the mechanical wave and generate an electrical output signal. In this way, the SAW acts like an electromechanical resonator. A change in the output signal from a SAW device, such as a change in frequency, phase and/or amplitude of the output signal, corresponds to changing characteristics in the propagation path of the SAW device. In some SAW device embodiments, monitored device frequency and any changes thereto provide sufficient information to determine parameters such as temperature, and strain to which a SAW device is subjected.
Additional background information regarding RFID technology and SAW devices may be had by reference to co-pending, commonly owned U.S. patent application Ser. No. 10/697,576, filed Oct. 30, 2003, entitled “Acoustic Wave Device With Digital Data Transmission Functionality” incorporated herein for all purposes.
In conventional implementations of SAW devices in tire-related applications, SAW sensors transmit information about the parameters being sensed. However, it is often the case that in radio frequency transmissions systems, especially low power systems, signal strength and/or noise, or more specifically the signal to noise ratio (S/N) becomes a limiting factor. While various implementations of acoustic wave devices such as SAW sensors in tire electronic systems have been developed, and while various combinations of information have been wirelessly relayed from a tire or wheel assembly using conventional technologies, no design has emerged that generally encompasses all of the desired characteristics as hereafter presented in accordance with the subject technology.
SUMMARY OF THE INVENTION
In view of the recognized features encountered in the prior art and addressed by the present subject matter, an improved methodology for the testing and calibration of interrogators for use with SAW based devices has been developed. It should be noted that although the principle portion of the remainder of the present disclosure may refer to the use of SAW based devices as being integrated with a tire or wheel structure, neither such use nor such particular type device is a limitation of the present technology as, in fact, such devices, whether SAW based or not, may be used in combination with a variety of other devices or elements or even as stand alone environmental sensors.
In an exemplary configuration, SAW based devices may include an acoustic wave device connected as a feedback element in an oscillator/amplifier and may be further coupled to an antenna element, thus forming an active transmitter arrangement. The acoustic wave device determines the carrier frequency (or frequencies) produced by such an active transmitter, and therefore, the frequency (or frequencies) of the transmitted RF signal represents one or more sensed parameters with the acoustic wave device itself functioning as a sensor. At the same time, the transmitted signal amplitude may be controlled by means of a separate circuit connected to the oscillator amplifier.
In one of their simpler forms, the transmitted signal from a SAW based device is switched on and off in a timed sequence, but other methods are possible. Positive aspects of this information transmission methodology include circuit simplification and power savings. For example, instead of requiring the circuitry in the tire to measure the sensed parameters, covert them to digital format, and encode them in a transmitted digital data stream, the sensed parameter information is conveyed through the transmitted RF frequency. Such methodology provides for the transmission of any other information desired, however complex or simple, by amplitude modulation of the transmitted signal. Such a circuit configuration provides for the ability to actively transmit a combination of information from integrated tire electronics to a remote receiver location. The combination of information may correspond to the physical parameters sensed by the acoustic wave device as well as digital data superimposed on the RF signal emitted by the acoustic wave device by selectively switching the amplifier on and off.
Another positive aspect of this type of device is that versatility is afforded to the types of information that can be transmitted via the electronics assemblies. Such information can include sensed information relating to parameters such as temperature and pressure associated with a tire or wheel assembly. Other information may include selected combinations of a unique tag identification, distance traveled, number of tire revolutions, vehicle speed, amounts of tread wear, amounts of tire deflection, the amount of static and/or dynamic forces acting on a tire, etc. So many different types of information are possible in part because a microcontroller can be configured to modulate any type of desired data on the RF output signal(s) from the electronics assembly and the subject calibration methodologies are able to insure reliable reception of the transmitted data.
Having recognized the above mentioned positive aspect associated with SAW based devices, the present subject matter recognizes and addresses the fact that there are, never the less, negative aspects associated with SAW based devices that are based on the retransmission of RF energy. Significant among these aspects is the extremely low power level at which the SAW devices transmit signal energy. While such low signal levels may be considered a positive aspect when considering operating energy requirements, these low levels, coupled with other aspects present challenges to data reception and recovery. More specifically, operation of SAW based devices at such low signal level, coupled with often hostile operating conditions and environments, may produce such low signal to noise (S/N) ratios that the accuracy and performance characteristics of the SAW based device's interrogation systems may be compromised.
In accordance with aspects of certain embodiments of the present subject matter, methodologies are provided to insure proper operation of the interrogation systems associated with SAW based devices. More particularly, methodologies have been developed to verify that the interrogators themselves are operating within established specifications.
In accordance with certain aspects of other embodiments of the present subject matter, methodologies have been developed to track the performance of SAW based device interrogators over the operational lifetime of the interrogators to insure reliable identification of data read problems and to provide a means for diagnosing such problems.
In accordance with yet additional aspects of further embodiments of the present subject matter, apparatus and accompanying methodologies have been developed to establish the health of the communications channel between a SAW device and it's associated interrogator.
According to yet still other aspects of additional embodiments of the present subject matter, apparatus and methodologies have been developed to insure the accurate reporting of read data by providing a mechanism for performance testing that may be easily employed prior to each and every data read operation.
In accordance with yet still further aspects of still further embodiments of the present subject matter, methodologies have been developed to account for the effects of ambient interference or background noise affecting the communication channel between a SAW device and it's associated interrogator.
Additional objects and advantages of the present subject matter are set forth in, or will be apparent to, those of ordinary skill in the art from the detailed description herein. Also, it should be further appreciated that modifications and variations to the specifically illustrated, referred and discussed features and elements hereof may be practiced in various embodiments and uses of the invention without departing from the spirit and scope of the subject matter. Variations may include, but are not limited to, substitution of equivalent means, features, or steps for those illustrated, referenced, or discussed, and the functional, operational, or positional reversal of various parts, features, steps, or the like.
Still further, it is to be understood that different embodiments, as well as different presently preferred embodiments, of the present subject matter may include various combinations or configurations of presently disclosed features, steps, or elements, or their equivalents (including combinations of features, parts, or steps or configurations thereof not expressly shown in the figures or stated in the detailed description of such figures). Additional embodiments of the present subject matter, not necessarily expressed in the summarized section, may include and incorporate various combinations of aspects of features, components, or steps referenced in the summarized objects above, and/or other features, components, or steps as otherwise discussed in this application. Those of ordinary skill in the art will better appreciate the features and aspects of such embodiments, and others, upon review of the remainder of the specification.
BRIEF DESCRIPTION OF THE DRAWINGS
A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures, in which:
FIG. 1 diagrammatically illustrates an operational relationship between an interrogator and a SAW based device mounted in a tire according to known practices;
FIG. 2 illustrates a basic operational relationship between a handheld interrogator and a SAW based device;
FIG. 3 illustrates a technique for verifying the operational capabilities and calibration of handheld interrogators in accordance with an exemplary embodiment of the present subject matter;
FIG. 4 illustrates an alternative technique for verifying the operational capabilities and calibration of handheld interrogators using paired interrogators in accordance with another exemplary embodiment of the present subject matter; and
FIG. 5 schematically illustrates an exemplary application of the present subject matter to a vehicle tire-monitoring lane in accordance with yet another embodiment of the present subject matter.
Repeat use of reference characters throughout the present specification and appended drawings is intended to represent same or analogous features or elements of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
As discussed in the Summary of the Invention section, the present subject matter is particularly concerned with the testing and calibration of interrogators for use with electronics assemblies that monitor and relay various information possibly related to tire identification and/or measurements of selected physical conditions associated with a tire, a wheel assembly, or some other item or area of interest.
Selected combinations of aspects of the disclosed technology correspond to a plurality of different embodiments of the present invention. It should be noted that each of the exemplary embodiments presented and discussed herein should not insinuate limitations of the present subject matter. Features or steps illustrated or described as part of one embodiment may be used in combination with aspects of another embodiment to yield yet further embodiments. Additionally, certain features may be interchanged with similar devices or features not expressly mentioned which perform the same or similar function.
Reference will now be made in detail to the presently preferred embodiments of the subject tire electronics assemblies. Referring now to the drawings, FIG. 1 illustrates aspects of a known tire monitoring system with a passively operating electronics assembly, including a condition-responsive device, such as an acoustic wave sensor. Tire structure 10 may incorporate a condition-responsive device 12 to monitor various physical parameters such as temperature or pressure within the tire or associated wheel assembly. Such a condition-responsive device may include at least one resonator-type sensor, such as a surface acoustic wave (SAW) resonator or a bulk acoustic wave (BAW) resonator. It should be appreciated in accordance with the present technology that a condition-responsive device can correspond to either of these specific types of sensors or to any commercially available acoustic wave sensor or other type of sensor that is resonant at a suitable frequency or frequencies. The passively operating assembly with condition-responsive device 12 of FIG. 1 may be energized by a remote source. Thus, a data acquisition transceiver 14 is typically provided with both transmitter and receiver electronics to communicate with the condition-responsive device 12 . RF pulses 16 transmitted from the antenna 20 of the transceiver 14 to the electronics assembly in tire 10 excite the SAW device, which may then store some of this energy and transmit a signal back to the transceiver at the end of each energizing RF pulse.
Referring still to FIG. 1 , transceiver 14 transmits an interrogation signal 16 that is intended to energize a given condition-responsive device 12 at its frequency of natural oscillation (resonant frequency) such that after an excitation pulse, each resonator element in condition-responsive device 12 radiates energy stored during excitation. Peak levels of this radiated energy occur at the respective resonant frequencies of the resonator elements in the condition-responsive device 12 . Such signals are then received at the transceiver 14 . By monitoring changes in the frequency of the signal transmitted back from condition-responsive device 12 , information corresponding to preselected condition(s) within tire structure 10 can be determined.
In accordance with aspects of the present invention, a condition-responsive device 12 may be provided that relays information in addition to the parameters sensed merely by the condition-responsive device itself. Such information may include, but is not limited to, data relating to the specific tire to which the condition-responsive device 12 is associated including manufacturing information, tire information, and other types of data as may be of interest. Such a condition-responsive device may be provided in conjunction with a tire structure in a variety of fashions. For instance, condition-responsive device 12 may be attached to the interior of a tire structure or some other location relative to a wheel assembly. Alternatively, condition-responsive device 12 may be embedded within a tire structure itself. Still further, condition-responsive device 12 may be encased in an elastomer material with appropriate dielectric properties that may then be adhered to or embedded within a tire structure. The condition-responsive device 12 may also be packaged in any number of ways and may be attached to the wheel assembly, the valve stem, or in any other place which allows for substantially accurate measurement of environmental conditions such as temperature and pressure as associated with the tire. In accordance with the variety of possible locations for condition-responsive device 12 , it will be appreciated in accordance with the present subject matter that a condition-responsive device “integrated” with a tire structure or wheel assembly is intended to encompass all such possible locations and others as within the purview of one of ordinary skill in the art.
With reference now to FIG. 2 , there is illustrated an exemplary embodiment of a handheld interrogator 40 for use with condition-responsive device 12 . Interrogator 40 includes a display panel 42 for displaying data read from condition-responsive device 12 and may also display other information relative to the interrogator 40 itself, for example, battery level or software version information. Display panel 42 may also be configured as a “touch” panel so as to perform the dual purpose of display and input control for the interrogator 40 . Alternatively, control elements (not shown) may be mounted to the exterior of the interrogator to provide control of it's various functions. An antenna 44 is mounted to interrogator 40 's main housing and supported remotely from the main housing by a support element 45 .
In normal operation, interrogator 40 may be programmed to transmit one or more signals 48 to condition-responsive device 12 . These signals, received by the condition-responsive device 12 via antennae 26 a , 26 b , may be used to instruct the condition-responsive device 12 to transmit collected and/or otherwise stored data to be read by the interrogator 40 . The transmitted signal 48 may also be rectified by elements within condition-responsive device 12 to supply operating power to the device. Alternatively, depending on the specific type of condition-responsive device 12 involved, interrogator 40 may only be required to read continuously or intermittently transmitted signals 46 transmitted autonomously by condition-responsive device 12 . There is the possibility also that the mutual operation of interrogator 40 and condition-responsive device 12 may require some combination of the two previously discussed operational modes. For example, interrogator 40 may not function as the power source for the condition-responsive device, but may be required to send a signal instructing the condition-responsive device 12 to “download” or transmit data. All such variations in operational characteristics are considered to be within the scope of the present subject matter.
As previously noted, one of the aspects involved with the operation of interrogator and RFID electronics assembly combinations is the heavy dependency of system accuracy and performance on the signal to noise (S/N) ratio of signals transmitted between the interrogator 40 and condition-responsive device 12 . There is, therefore, a need to be able to verify that the interrogators themselves are operating within specification. This verification should be performed over the life of the interrogator to insure that if the system reports a read problem, possibly indicated by too large a standard deviation, that there is a means of diagnosing the problem. In accordance with the present subject matter, a method has been developed to accomplish this objective by using a separate receiver to independently measure the transmitter output power from an interrogator. As an alternative, two interrogation systems with opposed antennas may be employed. These concepts are illustrated respectively in FIGS. 3 and 4 .
With reference to FIG. 3 , there is illustrated a first exemplary embodiment of the present subject matter in the form of a paired interrogator 40 and separate, dedicated, receiver 40 ′. The receiver 40 ′ may correspond to a relatively simple RF detector configuration comprising an antenna 44 ′ and a detector circuit as simple as a rectifier diode and metering element connected in circuit therewith or a more sophisticated receiver configuration may be employed. The receiver 40 ′ may include a display 42 ′ similar to that of the interrogator 40 to include not only a display, but also a touch screen control for the receiver. Alternatively, the receiver 40 ′ may include control elements (not shown) mounted to the receive housing. Of significance to the present invention is the concept that the separate receiver 40 ′ is physically placed at a predetermined, controlled distance from the interrogator 40 such that the separate receiver 40 ′ may obtain consistent, distance specific, power output readings from the interrogator 40 . A mounting arrangement (not shown) of suitable design may be employed to more easily effect precise placement of the interrogator 40 and separate receiver 40 ′. Taking such power output readings over time may assist in insuring accurate calibration of the interrogator 40 . In addition, further useful data may be developed regarding ambient RF noise levels in the vicinity of the interrogator to insure that the signal to noise level within the operating environment is sufficient to obtain accurate readings from the interrogator. For example, a reading of ambient RF signals may be taken by the separate receiver 40 ′ prior to energizing the interrogator 40 to establish a background noise level. Such readings may, for example, provide an opportunity to adjust the power output of the interrogator transmitter to take into consideration ambient noise levels to insure an adequate signal to noise ratio. Alternatively, in the instance of low ambient noise, interrogator transmitter power levels may be lowered to conserve interrogator battery power while yet maintaining adequate signal to noise level to assure accurate data recovery.
With reference to FIG. 4 , there is illustrated a second exemplary embodiment of the present subject matter in the form of a pair of interrogators 40 , 40 ″. Interrogators 40 , 40 ″ each include a display and/or touch control panel 42 , 42 ′ as well as individual antennas 44 , 44 ″. As illustrated in FIG. 4 , the interrogators 40 , 40 ″ are physically placed in spaced opposition to each other at a selected, controlled distance. As with the first exemplary embodiment, a mounting arrangement (not shown) of suitable design may be employed to more easily effect precise placement of the interrogators. The exact separation between the interrogators is a matter of choice, it only being required that the separation distance chosen is within the operational range of the interrogators and, of equal importance, that the same distance is used for any and all calibration/test sequences. Interrogators 40 , 40 ″ are configured such that a calibration mode may be initiated for each interrogator. Such configuration may include, but is not limited to, provision of additional firmware or software with the operational control elements of the interrogators that permits self-calibration and/or testing of the interrogators.
A typical example of a test/calibration sequence may include verification of the transmit power from a selected interrogator 40 or 40 ″. Such a test may be accomplished by transmitting a signal 48 from interrogator 40 and measuring the signal level received by an opposing paired interrogator 40 ″ and vice-versa. Moreover, the receiver portion of each of the transceivers 40 , 40 ″ may be employed to obtain ambient background RF level readings for it's paired transceiver to establish accurate background noise levels for the separated interrogators. By exchanging test signals between opposed interrogators and using reference values established when the units are new or immediately after calibration or servicing, the performance of the interrogators can be continually tracked and a request for service can be generated upon observation of significant deviations from previously established reference norms prior to any interrogator failure.
With reference now to FIG. 5 , a third exemplary embodiment of the present subject matter will now be described. Illustrated in FIG. 5 is an exemplary configuration of a drive-by interrogator arrangement of this embodiment of the present subject matter. In this exemplary configuration, a plurality of interrogators 50 , 52 , 54 , 56 are arranged in an array of four columns, each containing eight interrogators. As should be evident to those of ordinary skill in the art, the exact total number of interrogators included in such an array would depend on the specific use to which the array is placed. In the presently illustrated exemplary configuration, the array of interrogators is configure to permit a multi-wheeled vehicle to pass through a lane 70 with the interrogators positioned in such manner as to allow the tires 60 , 62 , 64 , 66 of such a vehicle to pass between adjacent columns of interrogators. In this manner and under normal operations interrogator 50 is in a position to read data from tire 60 while interrogator 62 reads data from tire 62 , interrogator 54 from tire 64 , and interrogator 56 from tire 66 .
An important aspect arising from the exemplary embodiment of the present subject matter illustrated in FIG. 5 is that the various interrogators of the array are normally placed in fixed relationships to one another. Such placement allows the antennas that are normally placed in opposition to each other to partner with its opposing antenna to perform the testing function. In fact, since the antenna array elements permanently have available to them a paired antenna, the system can be configured to perform a testing operation prior to every data read. Moreover, passage of such an “each and every” read test may be used as a gating criterion prior to allowing a vehicle to enter the lane.
Yet another significant aspect arising from the permanent placement of an array of interrogators resides is the fact that since the interrogators are positioned in their normal use positions, the constant availability of a testing partner interrogator allows the array to test the health of the communications channel between interrogators prior to every read. Such testing allows the system to adjust power levels to compensate for deleterious effects such as from rain, snow, ice and other adverse environmental conditions.
With respect to each of the previously discussed exemplary embodiments of the present subject matter, the various tests performed may include such as frequency, power, noise floor, clock stability, and distortion. In order for the interrogators to perform such tests, each interrogator may have incorporated therein additional circuitry, firmware, or software that will allow a diagnostic routine to be run while at the same time adjusting transmitter frequency and power levels in predictable ways as well as the ability to measure the same.
While the present subject matter has been described in detail with respect to specific embodiments thereof, it will be appreciated that those skilled in the art, upon attaining an understanding of the foregoing may readily produce alterations to, variations of, and equivalents to such embodiments. Accordingly, the scope of the present disclosure is by way of example rather than by way of limitation, and the subject disclosure does not preclude inclusion of such modifications, variations and/or additions to the present subject matter as would be readily apparent to one of ordinary skill in the art. | Disclosed is an apparatus and methodology for insuring measurement accuracy and performance reliability in the operation of devices employed to interrogate SAW devices. The present subject matter relates to an arrangement and methodology that provides an interrogator paired together with a separate receiver, which may comprise a second interrogator, functioning together to perform a self-testing operation. The interrogator may be a handheld device that is temporarily paired with a separate receiver or a like device or the interrogator may correspond to more or less permanently paired set of devices physically placed in an array. | 1 |
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of U.S. Provisional Application No. 60/151,503, entitled “Search Verify Engine to Verify Streaming Audio Sources,” filed on Aug. 30, 1999, the subject matter of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates generally to accessing media content over a network and more specifically to the classification and monitoring of media content.
2. Description of Related Art
The Internet allows digital communication between a server computer and a client computer using various protocols, such as: protocols for the World Wide Web (WWW or Web), such as HTTP (Hyper-Text Transport Protocol), HTML (Hypertext Markup Language) or XML (eXtended Markup Language); protocols for media streams for playing audio or video content, such as MP3 (Motion Picture experts group, audio layer 3) and RM (Real Media); and protocols for wireless applications such as Wireless Application Protocol (WAP).
The WWW often serves as the user front-end for various non-WWW protocols (e.g., media streams and WAP), which are technically Internet services that are not part of the Web. For example, Web pages include text, graphics and access to streaming media resources, such as audio or video content. The user accesses the various content types by means of a browser or a media player, which may be a browser plug-in or a stand-alone application.
A unique Uniform Resource Locator (URL) identifies each computer resource on the Internet. To establish a connection with a particular resource on an Internet server, a user at a client computer sends a request to the URL associated with the desired Internet resource. User URL requests are usually made by typing the URL address directly into an address request box or by selecting a hypertext “hot link” referencing that URL. When the desired connection is formed between the Internet server and the client computer, the user is capable of interacting with the contents of that Internet resource.
Audio and video have been commonly accessible from Web pages since the introduction of media players such as RealPlayer® from RealNetworks® of Seattle, Wash., or Windows® Media Player from Microsoft® of Redmond, Wash., and other similar products. Such media content is usually played using a process called media streaming. Media streaming is a technique for transferring data from a server to a client across a network such that the data is processed and played as a steady and continuous stream. On-demand media streams, such as individual music works, news broadcasts, or program archives, have a fixed playing duration. Live media streams, such as simulcasts of broadcast programming or continuous entertainment services, usually have an unlimited length.
Users generally want to connect with high quality resources that provide the type of entertainment or service of their preference. However, conventional streaming media sources suffer from a variety of deficiencies. If the data cannot be transmitted fast enough between the server and the client due to network delays or user congestion, then short interruptions or garbled fidelity are experienced while the player catches up with the missed content. Furthermore, there is usually an upper limit to the number of simultaneous users that the media site can support, so new users may be denied service if they try to access the URL of the media component. Finally, some media streams may be out of service for a variety of other reasons, including technical problems, content carried on an associated broadcast station but specifically “blacked out” from Web streaming by the rights owner, human error, or a decision to no longer provide the Web services.
There are many different Web sites that provide a directory of audio, video or TV resources. Most of these directories are updated only occasionally, so that the directory listings are often substantially out of date due to the rapid pace of change experienced by media stream sites. There are thousands of media servers on the Internet, and users would like to keep up to date with the many highly dynamic changes affecting reception quality, availability, content, and broadcast schedule.
SUMMARY OF THE INVENTION
The invention is an automated method and a computer program for periodically evaluating media streams on a network of computers. The method and program determine the availability of various media streams and identify various characteristics of each stream. One embodiment of the method includes the steps of periodically obtaining a first and second group of addresses, attempting to establish communication with each media stream, terminating the connection if the connection was established, and reporting the results. Each address identifies a location of a media stream on the network. The second group of addresses only includes those media streams that were previously identified as being unavailable. The step of attempting to establish communication with each media stream is done to determine a characteristic of the media stream. However, even if communication is not established, that fact alone is valuable information that should be reported. A preferred embodiment of the invention periodically obtains the second group of addresses more frequently than the first group so unavailable media streams are verified more frequently than all other media streams.
Another embodiment of the invention includes the steps of periodically obtaining addresses, attempting to establish connections with the media streams using the addresses, determining the transmission rate of each media stream, and updating records that contain information about the media stream with information concerning whether a connection was made to each media stream and, if a connection was made, reporting the transmission rate.
In another aspect of the invention, a computer program includes a control loop and at least one stream verification routine. The control loop obtains a block of addresses from a database each time verification is required. The stream verification routine first receives an individual address from the control loop, then verifies that the media stream is capable of being accessed, and then delivers the results back to the database. Several different stream verification routines can be used if the available hardware can support simultaneous connections with the media streams.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1A is a block diagram illustration of the various systems associated with the invention.
FIG. 1B is a block diagram illustration of the Universal Stream Tuning System (USTS).
FIG. 1C is a block diagram illustration of the URL Verification Engine (UVE).
FIG. 1D is a block diagram illustration of the database system.
FIG. 2 is a flow chart illustrating a process for logging on to the USTS server.
FIG. 3 is a flowchart illustrating a process for filtering, displaying, selecting, and playing media streams.
FIG. 4 illustrates a state diagram for the URL (Uniform Resource Locator) Verification Engine.
FIG. 5 shows the method used for filling out records in the Stream Database.
FIG. 6 is an illustration of a representative Web page tool bar that interacts with the USTS database.
FIG. 7 is an illustration of a representative interactive display of stream categories and subcategories produced from the Stream Database.
FIG. 8 is an illustration of an interactive display that provides interactive results produced from a Stream Database search.
FIG. 9 is an illustration of an interactive display that provides additional stream details provided from the Stream Database.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1A shows various systems that may communicate through the Internet 110 . The Internet 110 is conventional and comprises a collection of networked computer nodes capable of exchanging data packets using standard transmission protocols. The Internet 110 is explained in the reference LAN Times Encyclopedia of Networking , Tom Sheldon, 1994. One such set of protocols conventionally referred to as media stream protocols, enables the transmission of various media streams between nodes throughout the Internet 110 .
A Universal Stream Tuning Service (USTS) 120 enhances the ability of users to locate and receive media streams from the Internet.
The USTS 120 provides a very general tuning service designed to enable use of the USTS from a plurality of other USTS-enabled services 130 , including Web sites 128 and other protocol servers 129 , which may be provided by third parties. The design of the USTS allows the look, feel and content of the other USTS-enabled services 130 to be customized to the particular needs, formats, user equipment types, concepts and business model of each service provider.
The streams used with the USTS are sourced from media stream provider servers 140 . Content supplied from media stream provider servers 140 may include:
Internet simulcasts of conventional radio and TV broadcasting programs;
On-demand streams, such as playing the latest news or weather on request, or playing selections from an entertainment library;
Netcasts, which can have similar programming formats to conventional broadcasting, but are carried only over the Internet;
Live events, such as concerts, sports, press conferences, conventions, etc.;
Premium services, which are subscription services to any type of media content;
Preferential logons, which are subscriptions to a priority server that provides access when public servers are busy; and
Archives, which contain programs broadcast previously.
A codec (compression/decompression) server 144 may be provided in media stream provider servers. Codec servers provide streams that are compressed and coded for specific players such as RealPlayer® or Windows® Media Player, and other similar products.
The user equipment 150 contains at least one codec player 154 , and may take many different forms: desktop computers with different operating systems (Windows®, Mac®, UNIX, Linux®, and other conventional operating systems); TV Web appliances, which use special computer-based equipment to display or play Web or Internet content over a TV set; Internet appliances, such as Internet radios and Web telephones; wireless laptop computers, or wireless Personal Digital Assistants (PDAs); wireless telephones; or game consoles with Internet capability.
Therefore, the USTS 120 assists users in finding and enjoying streams from a wide selection of media streams using a wide variety of stream reception equipment.
FIG. 1B is a block diagram illustrating the Universal Tuning Service (USTS) 120 , which comprises at least one Internet connection 121 , and may have a plurality of USTS servers 122 . The USTS server 122 may be comprised of a database system 123 , a content handler 124 , a USTS server management system 125 , a URL Verification Engine (UVE) 126 , Web page files 131 , and other protocol files 132 . The USTS servers 122 may be sited at the same location, or may be geographically distributed. The content handler 124 and the Web page files 131 may host direct Web pages for the USTS 120 or may host Web pages having USTS capabilities developed for or by third parties.
FIG. 1C is a block diagram illustrating the UVE 126 , which comprises a stream verification system 127 , a connection 133 to the USTS server manager system 125 , a UVE management system 134 , a URL block handler 135 , a time-of-day handler 136 , and a verification scheduler 137 .
FIG. 1D is a block diagram illustrating the database system 123 . Blocks referred to as a database may also be database subsets or tables. The database system 123 . comprises a connection 141 to the USTS server management system 125 , a database management system 142 , a stream database 145 , a user database 146 , an advertisement database 147 , a sponsor database 148 and a stream categories database 149 .
FIG. 2 illustrates the log-on process to gain access to the USTS 120 . A log-on step 200 enables a user of a USTS session hosted by the content handler 124 , the Web page files 131 , the other protocol files 132 , or other USTS-enabled services 130 to interface with the USTS 120 . One entry point 210 to the USTS 120 provides indirect access for other. USTS-enabled services 130 , and the other entry point 214 provides direct access through the content handler 124 , Web page files 131 or other protocol files 132 . Users other USTS-enabled services 130 are connected to the USTS in a step 220 , which may include authentication and recording the identity of that USTS-enabled services 130 . The USTS 120 is provided with the identity of the internal or external services enabling access to the user in a step 230 . If the the content handler 124 , the Web page files 131 , the other protocol files 132 , or other USTS-enabled services 130 collect or forwards a user ID, that is also recorded by the USTS in the step 230 .
The USTS 120 allows users to be anonymous. However, since there are advantages to being a registered user, the user is optionally permitted to register in step a 240 . If the user wants to register, the USTS 120 requests user information and equipment information such as user name, address, e-mail address, Internet connection bandwidth and types of codec players 154 installed on the user's system 150 in a step 250 . The USTS 120 creates a user search profile that is used to filter out media streams that do not apply to the user in a step 260 . If the user is not registered, then the USTS 120 uses a search profile based only on the Web page or Internet service ID. Since the searches of non-registered users are not custom-filtered, search results of non-registered users may include many records that the user is unable to play. On the other hand, if the user is registered, then the USTS 120 creates a search filter profile based on the capabilities of user equipment 150 , codec player(s) 154 , and perhaps the individual user ID. Consequently, registered users get search results that are tailored to what the user is able to play.
FIG. 3 shows the details of the stream search, display, select and play step 270 . After log-on activities the USTS server 122 creates a stream categories table for the session from the stream categories database 149 through interaction with the database management system 142 . The stream categories table may be tailored to meet the preferences of the other USTS-enabled services 130 . All or a portion of the resulting session stream categories table may be displayed to the user in a step 310 . The stream categories table may include only main categories or may be a hierarchical table listing all stream categories and subcategories. If subcategories are used, they may be displayed after selecting a category; or may be directly listed underneath each category.
The user selects a category or subcategory in a step 330 using any conventional interactive user control, such as any type of hypertext link, a user button, or an equipment function button, which records the selected category or subcategory. The USTS 120 , through interactions that may involve the database management system 142 , the stream database 145 , and the user database 146 , then performs a search for streams and displays the streams from the stream database 145 that match the category table description selected and the user filter profile.
The ability to perform a custom search may be provided by the USTS 120 in a tool bar interactive display or may be in a dialog box that the user accesses by standard means such as selecting a user button or a menu item. If this capability is provided, the user may use interactive text field or other interactive devices to describe the desired search. Although step 320 , the option of performing a custom search, is shown after step 310 in FIG. 3, it may be used at any time prior to selecting a media stream in a step 350 . The USTS 120 then locates and displays matching streams in the stream database 145 using the search specifications and user filter profile.
At step 350 , the user interactively selects one media stream to play, either a category/subcategory stream choice from step 330 or a search results stream choice from step 340 . The stream selection means may be any interactive user control which provides a link to a stream file, such as any type of hypertext link, a user button, or an equipment function button.
The same audio or video content may be available from a plurality of media streams, which may be identical streams, streams with a different codec format, or streams with a different bandwidth. Identical streams that are “mirrored” allow more users to access the content and the redundancy allows user to gain access to the material even if one stream is down. Mirrored streams in different geographical location additionally prevent regional outages from effecting users. Mirroring could be accomplished by the media provider, third parties, or stored on the USTS 120 .
By uniquely identifying each individual item of media content in the stream database 145 , users would request content and not individual media streams. The USTS 120 could then analyze the request and determine which media stream is the most appropriate for that particular user, based on geography, congestion, preferential log-on, and any other factors deemed appropriate. The USTS 120 could then redirect the URL to the appropriate media stream. Therefore, if the same request for media content were executed at different times or different locations, the user might be connected to different streams. By using this redirection, the user could bookmark media content and not be concerned with the details of which streams are available and always be redirected to the best media stream, have the best available same to be played.
In a step 370 , the USTS 120 calls and plays the optimum URL determined in a step 360 . Many players allow the user to pause or end the stream at any time by using player controls. In a step 380 , the user can either loop back to step 310 to look for a new stream or exit from the USTS at a step 290 . Once the connection to the third party media stream is made, the media stream may continue to play regardless of whether the user browses for a new stream or exits from the USTS 120 in step 290 .
FIG. 4 shows a state diagram for the UVE 126 shown in FIG. 1 C. States are shown in rounded boxes, and transition events are shown in text along the arrows between the states. After the stream verification system 127 begins running in a state 405 , it automatically enters the top of a stream verification control loop 410 , which waits until a scheduled verification time occurs. Preferably, there are at least two scheduled paths for verifying streams based on the stream characteristics and selected verification intervals.
Streams listed in the stream database system 145 may be categorized as having a status of play, busy or down. An event 415 occurs at the next scheduled time for checking all current streams. The verification scheduler 127 periodically requests blocks of active media stream URLs from the stream database 145 , which may be managed by the UVE management system 134 and the URL block handler 135 . Event 415 leads to a state 420 , which obtains all current stream URLs from the stream database 145 . An event 425 occurs at the next scheduled time for rechecking streams that were busy or down the last time that they were checked. Event 425 leads to a state 430 , which obtains those stream URLs from the stream database 145 that were previously down or busy.
The verification check schedule in events 415 and 425 managed by the verification scheduler 137 involve performance tradeoffs. Verification checks need to be scheduled often enough that the stream data is reasonably current, but not so often that the verification process imposes an unnecessary load on the stream servers or make it impossible to complete checks all of the streams in the available time. Verification checking of all streams in event 415 is typically scheduled for about 60-minute intervals but checking intervals of between 15 minutes and 8 hours may also be used. Even if the resources allowed stream verification of greater than once every 15 minutes, it would not be desirable to check the streams so often that the UVE 126 puts an unreasonable load on the stream providers 140 . Similarly, it is certainly possible to conduct stream verification at intervals greater than 8 hours, but that would probably result in at least some of the users being dissatisfied by finding stations whose actual status is incorrectly recorded in the database for much of the day. Checking of down or busy streams is a separate event 425 so that such inactive streams may be checked more frequently in order to quickly discover streams that have returned to play status.
An event 435 occurs upon completion of the complete URL transfer under the direction of the UVE block handler 135 from either state 420 or 430 , and leads to state a 440 , which incrementally loops block-by-block through the entire URL list. State 440 automatically passes to a state 450 , which checks stream details of each URL in the URL block.
State 450 preferably uses a plurality of network connections, such as a plurality of active network sockets in the USTS server management system 125 , so that a plurality of different URLs can be called and checked simultaneously. The first URL check performed by state 450 is to attempt connection to each stream. If the stream starts normally and a starting portion of the stream content has been read, the stream status is recorded in stream database 145 as play. If the stream server returns a “busy stream” message, the stream status is recorded as busy. If a connection cannot be made to the stream or reading the stream fails before the entire starting portion of the stream has been read, the stream status is recorded as down.
If the stream status is play, then various characteristics are obtained from the header, such as the specific codec type used to generate the stream, whether stereo is present, and the stream data rate. The starting portion is preferably about 1 Kilobyte, which is usually enough data to determine all of the various characteristics of the stream. All results are recorded in the corresponding dynamic fields of the stream table of the stream database 145 .
The UVE 126 , however, is not the only way to accomplish stream verification. An alternative method, which can be used to augment the UVE 126 or in place of the UVE 126 , is to have the user equipment 150 report the status of media streams. Once the user has made a request for media content and obtained the appropriate stream URL, the user equipment 150 could be configured to analyze the stream and report the stream's characteristics back to the UVE 126 . Although the usage patterns of users accessing media are not as predictable as the UVE 126 , enough users have the potential of generating the same or better results than the UVE 126 . However, in order to utilize this method, the USTS 120 must be able to exert some control over the user equipment 150 . The user equipment 150 would need to be configured to report back to the USTS 120 .
The database system 123 may be implemented with a relational database. Some database fields are essentially static and change only rarely, if at all. These fields represent information that was entered manually into the database system 123 . Other database fields are subject to frequent changes, due to continual verification checks by the UVE 126 . The remaining fields are changed only occasionally, such as user preferences, equipment or players supported.
In the field tables that follow, an asterisk (*) indicates fields that may be occasionally changed manually at the USTS 120 , or by users or advertisers, and a double asterisk (**) indicates fields that may be changed frequently by the UVE 126 or the USTS server management system 125 . Change to other field may originate with USTS personnel or the stream providers, who may notify the USTS 120 of the changes. Other changes may be discovered by USTS personnel or from reports of users. The timeliness of manually entering such changes in the database system 123 is limited by available staffing.
The stream characteristics records in stream database 145 may have fields such as:
Station Description Fields:
Station ID
Station Status (Play, Busy, Down)**
Station Name (Call Letters or Name)
Station Additional Description
Station Frequency
Station Geographical Location
Main Language Used
Station Service Type (Simulcast, Netcast, Archive, etc.)
Flag Indicating Stream Access Provided through a Stream Distributor
Station Broadcast Categories/Subcategories
Station Key Words
Station Info Web Page URL
Date Station Info URL Last Verified/Checked**
Number of Streams Carried**
Audio Stream Sub-tables (Multiple streams may be listed per station):
Stream Format (Codec Type)**
URL of Standard Web Page Associated with Stream*
Stream Metafile* or **
Stream Average and Maximum Bandwidth**
Title/Author/Copyright**
Stereo Flag**
Live Flag**
Recordable Flag**
Stream Availability/Reliability**
Stream Score**
Stream Status (Play, Busy, Down)**
Time Stream Last Checked/Validated**
Number of Times Stream Played by Users**
Stream Approved for Users Flag*
Include in Current “Cool Streams”*
A stream metafile is a file containing the file names of a set of stream files. The stream metafile is accessed with the HTTP protocol, while the files it contains are accessed with stream protocols.
The stream score is calculated from other fields and may be either included as a database field, calculated by the USTS 120 software, or calculated by the other USTS-enabled services 130 . The stream score is calculated as a weighted product of various stream parameters, which may include a stream bandwidth score, a codec format perceived-quality score and the measured availability of the streams. For example:
Stream Score= W 1 *BandwidthScore+ W 2 *CodecScore+ W 3 *Availability,
where W 1 , W 2 and W 3 are the relative weightings of the scoring criteria.
The BandwidthScore is approximately proportional to the stream bandwidth (either average or maximum, or a weighted combination of both). The CodecScore is a qualitative score based on user-perceived quality of streams using that type of Codec Server/Player combination. Availability is the fraction of the time that the stream is available to USTS users (i.e., in “play” status). The weighting factors or CodecScore values that are used will depend upon the particular business model, philosophy and operator judgement used in running the Web page management system 124 or other USTS-enabled services 130 .
For example, in one implementation where bandwidth is considered very important, CodecScore is considered somewhat important and access is disregarded, the weights may be:
W 1 =0.7
W 2 =0.3
W 3 =0
The corresponding ranges of weighted parameters used may be:
BandwidthScore range: between 0.5 and 10.0
CodecScore range: between 3.0 and 9.0
Availability range: not considered
Therefore, the range of the stream score in this illustration would be between (0.7×0.5+0.3*3.0)=1.25 and (0.7*10.0+0.3*9)=9.7. The stream scores may be rounded off downward to the nearest integer, to give an easily displayed range of between 1 and 9, such as by using a bar display for each stream having between one and nine bar segments.
The stream score can be used in a variety of graphical or text indicators that are embedded or otherwise included in the stream search results so that the user can anticipate how “good” stream reception will be.
The user database 146 allows certain fields to be registered with the USTS 120 or to be updated during a user session. The user database may have field such as:
User Fields:
User ID
User Status (active, inactive)
Last and First Name
User Address*
User Telephone*
Flag for Credit/Billing Problems*
Payment Method (Credit Card, EFT)*
User Stream Presets*
User Favorites*
Codec Player Formats Available on User Equipment*
The advertisement database 147 might contain data for advertisements, such as banner ads or streaming ads than can be inserted into the media content. The advertisement database 147 may contain fields such as:
Ad Fields:
AD ID
Ad Status*
Ad Name
Ad Sponsor
Ad Description*
Ad Type/Classification
Ad Demographic targets*
Ad Play Frequency*
Ad Priority*
Total Plays of Ad Requested*
Ad Play Count**
Count of User Responses to Ad**
The sponsor database 148 may be used in conjunction with the advertisment database 147 . The sponsor database 148 contains all of the administrative contacts and billing information for the sponsors of the advertisements contained in advertisement database 147 .
FIG. 5 shows the method used to prepare and update the relatively static fields of the stream table portions of the database system 123 . The method starts at a step 510 . In step 510 , the various media streams are identified and new records are created in the stream database 145 under the direction of the database management system 142 . Media streams are located based on information provided by site developers, publications, system users, or from the results of search engines. Hereafter, references to a “manager” or “editor” refer both to people performing the tasks or the use of computer assistance or software that may automatically perform at least portions of the task. In a step 530 , an evaluation manager performs preliminary content and signal evaluations of each stream. In a step 540 , a content manager approves and specifies those streams that will be entered as a user-accessible record in the stream database 145 . The content manager duties may include saving the Web page URLs to be used in writing portions of the stream description and extracting the URLs of media streams from Web pages being screened, and entering both types of URLs into the stream database 145 . In a step 550 , a database editor, who may be the same person as the content manager, writes database fields that describe and categorize each user-accessible stream based on materials collected previous steps. In a step 560 , stream records which were approved for inclusion in the user-accessible records and have all field completed are made available to stream database 145 users by setting a record status flag to “user-accessible.”
Since there are other USTS-enabled services 130 that may use the USTS 120 , the USTS 120 design makes it easy to customize the interactive displays obtained from the database system 123 so that a variety of different user display types are produced. To illustrate how the different aspects of the invention may be displayed to users, a representative Web page is shown in FIG. 6 .
A Web page might include a tool bar set 600 and a user interactive display 660 . The tool bar set 600 could include a search and access tool group 610 that contains interactive buttons and input fields to guide stream searches or to access other USTS Web pages. Stream search options may include beginner or advanced searching capabilities. Across the bottom of search and access tool 610 are a number of hot-links that directly access other useful Web pages, such as
A tuning Web page showing a number of major categories and subcategories of media content (See FIG. 7 );
An advanced search display, which allows users to conduct advanced custom stream searches;
A presets Web page, which allows users to directly set known stream URLs as one of the stream presets;
A favorite Web page, which allows users to list many preferred streams which are too numerous to include as one of the fixed number of presets;
A downloads Web page, which allows users to download stream-related plug-ins, such as media players; and
A help Web page, which provides conventional help to USTS 120 users.
A presets tool group 620 selects and plays a stream that the user has previously selected on one or more of the other Web pages.
A log-in Dialog 630 allows users to register with the service so they may later access all of their user preferences, presets and favorite streams.
A “cool streams” display 650 contains a plurality of stream links which the Web site editors believe would interest either a broad range of users or users with a particular profile. Each item in the cool streams display 650 contains a direct hot-link to that media stream. The Web site staff can periodically rotate the contents of the cool streams display for variety and to reflect popular trends.
The user interactive display 660 is frequently shown simultaneously with the tool bar and can contain varied contents such as advertisements, news, directories, search results of station details. The User Interactive Display 660 is reserved for the user interactive displays unique to each different Web page. FIGS. 7 through 9 show a series of different examples of user interface display contents.
FIG. 7 shows a directory that indicates the major categories and subcategories that are commonly used to classify streams. Selection of one such subcategory conducts a search filtered by the user profiles, and a corresponding interactive display of results is presented.
FIG. 8 shows the results of a simple keyword search resulting from the use of search fields in tool bar 600 . Use of a category selector 720 may also produce a similar display.
A search status box 820 shows the number of matches to the user's search criteria. If the display is the result of selecting a choice from the category selector 720 , then the search status box 820 can also display the total number of streams in this subcategory and provide a simple navigation interface that allows the user to return to a higher category in the hierarchy. A sort options Bar 830 might allow the user to re-sort the match results in order of signal strength, city, stream name, popularity or format. All of the matches are shown in a results box 840 .
The top line of the results boxes 840 and 850 shows the stream name, the city of origin, the stream subcategory, and a Web site link. The second line, and possibly additional lines, in the results boxes 840 and 850 show:
The stream score indicated graphically;
The bit rate and type of media stream;
Buttons or other selection devices for choosing that stream as one of the preset streams (using a numbered button) or to a favorite (using the + button); and
A button or other interactive device displaying the stream status (play, busy, or down) and enabling the user to play that stream, if it is in play status.
The last section of results display 840 and 850 contains a brief description of the stream. A “More Info” interactive device, such as a hot-link or button, allows the user to access a more complete listing of this stream, such as is shown in FIG. 9 .
FIG. 9 illustrates a user interactive display 660 that contains more detailed information on a particular stream. Displays 910 and 920 have the same contents as the second line of the results boxes 840 and 850 . A stream detail table 930 provides in-depth information on the stream.
Although the invention has been described in its presently contemplated best mode, it is clear that it is susceptible to numerous modifications, modes of operation and embodiments, all within the ability and skill of those familiar with the art and without the exercise of further inventive activity. Accordingly, that which is intended to be protected by Letters Patents is set forth in the claims and includes all variations and modifications that fall within the spirit and scope of the invention. | An automated method for periodically evaluating media streams on a network of computers. The invention is used to determine the availability of various media streams and identify various characteristics of each stream. By repeatedly obtaining the addresses, attempting to establish communication with each media stream, and then reporting the results the system can verify that each media stream is accessible and report various characteristics of the stream. | 8 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a spring-assisted lifting mechanism, such as a door or shutter, for a dishwasher.
2. Discussion of the Related Art
The spring-assisted lifting mechanism is used, in dishwashers for the catering trade, to facilitate the operation of raising a covering means covering the dishwashing chamber. The spring-assisted lifting mechanism is intended to bring about a smooth-running movement of the covering means between a bottom position and a top position, the covering means being retained in the bottom position by its own weight and the [sic] retained in the top position by a spring force.
A known spring-assisted lifting mechanism for a covering means of a catering-trade dishwasher comprises two levers mounted on a shaft, the covering means being mounted in a rotatable and displaceable manner on the first lever, and a tension spring acting at the end of the second lever. The shaft, on which the levers are mounted, is fixed on the frame of the dishwasher via the second lever, with the aid of the spring, a moment is applied to the shaft. This moment brings about or assists a rotation of the shaft and/or of the first lever, with the result that an opening movement of the covering means is facilitated. In order to ensure vertical movement of the covering means, the covering means is guided, on the rear side, in a guide fitted on the frame of the dishwasher.
However, this lifting mechanism has considerable disadvantages. For example, a high force is necessary for the purpose of opening the covering means since, in this position of the lifting mechanism, the spring only acts on the shaft with a small effective lever length. As the covering means is opened to an increasing extent, the effective lever length increases, with the result that the lifting force acting on the covering means becomes greater and greater. During this opening operation, the operator initially senses a high resistance because the opening movement is only assisted to a minimal extent. Since the operator applies the force in accordance with the necessary opening force, the covering means is often displaced upward against a stop at high speed. This takes place because, on account of the improving lever arm between the spring and the shaft, the force which is to be applied by the operator decreases as the degree of opening increases. It is also the case that during closure of the covering means the properties of the mechanism result in an undesired, disadvantageous force profile. This is manifested in that first of all a large force and then an increasingly smaller force has to be applied in order to move the covering means from the top position into the bottom position. This characteristic of the lifting mechanism results in the operator first of all having to apply a large force in order to set the covering means in motion and then, on account of the resistance becoming lower, has difficulties in slowing down the covering means before the bottom position has been reached.
SUMMARY OF THE INVENTION
The object of the invention is to develop a spring-assisted lifting mechanism which, in all positions of the covering means, provides a load-relieving moment, which is adapted to the requirements of the operator, and thus allows exact, high-precision operation of the covering means with a small manual force.
The spring-assisted lifting mechanism for the covering means according to the invention comprises a control means which is arranged between the second lever and the tension spring a which brings about a more or less constant effective lever between an articulation point of the spring and the shaft over an angle of rotation of the shaft of up to approximately 100 degrees. This achieves the situation where the opening movement of the covering means is assisted by a virtually constant force, with the result that a force profile which is not, expected by the operator is not produced either during raising or during lowering of the covering means.
According to a preferred embodiment of the invention the control means is configured as an intermediate lever which is connected to the second lever and the tension springs In this case said intermediate lever at times is retained freely between the articulation points and at other times butts rotatably and displaceably against a support. This design allows a cost-effective, straightforward and space-saving embodiment of the lifting mechanism with more or less constant spring assistance.
An advantageous embodiment of the subject matter of the invention makes provision for the control means to be configured as a triangular compensating lever or toggle lever. Such a configuration of the control means allows the shaft to be used as a support and thus the design to be particularly straightforward.
According to a variant of the subject matter of the invention, it is provided that [sic] to design control means as a bolt which is mounted in two guide means and on which the spring is fastened. The guide means are formed by a slot in the second lever and by a fixed guide. This likewise makes it possible to provide a constant torque on the shaft since the effective lever remains constant.
A further variant of the subject matter of the invention provides that the second lever has a cam-like head, over the end side of which there runs a cable or band, the spring being fastened at the free end of said cable or band. If the end side of the cam is designed such that it is located on a circle around the shaft, then it is also possible in this case, with the aid of the spring, to apply a constant moment to the shaft.
BRIEF DESCRIPTION OF THE DRAWINGS
Further details of the invention are described, with reference to schematically illustrated exemplary embodiments, in the drawing, in which:
FIG. 1 shows a schematic side view of a dishwasher with the door closed,
FIG. 2 shows a detailed illustration of the lifting mechanism marked by “X” in FIG. 1,
FIG. 3 shows a schematic illustration of the dishwasher with the door half open,
FIG. 4 shows a detailed illustration of the lifting mechanism of the dishwasher when the door is half open,
FIG. 5 shows a schematic illustration of the dishwasher with the door open,
FIG. 6 shows a detailed illustration of the lifting mechanism when the door is open,
FIG. 7 shows a schematic illustration of a variant of the lifting mechanism, and
FIG. 8 shows a schematic illustration of a further variant of the lifting mechanism.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 illustrates a schematic side view of a dishwasher 1 . The dishwasher 1 comprises a substructure 2 with feet 3 and a side part 4 which is fastened on the substructure 2 . The dishwasher 1 also has a covering means 4 a , which is configured as a door 5 which has a handle 6 . Seated in the side part 4 is a bearing 7 which is configured as a shaft 8 . Two levers 9 , 10 are fastened on the bearing 7 or on the shaft 8 . The lever 9 connects the shaft 8 to a rotatable bearing bolt 11 which is fitted on the door 5 . The lever 9 is mounted displaceably in a guide 13 of the shaft 12 . During opening of the door 5 , the lever 9 slides back and forth in the guide 13 of the bearing bolt 11 by way a region 14 (cf. FIG. 3 and FIG. 5 ). The vertical movement of the door 5 is ensured by a vertical guide (not illustrated) which is arranged between the door and the side part.
It can be seen from FIG. 2 that the lever 10 is connected rotatably to a control means 16 at an articulation point 15 . The control means 16 is configured as a compensating lever 16 a or triangular lever 17 which has a base 18 , a side 19 and a side 20 . Suspended at a further articulation point 21 of the triangular lever 17 is a spring 22 which has a longitudinal axis 22 a . The spring 22 is designed as a tension spring 23 and is supported in the side part 4 of the dishwasher 1 (see FIG. 1 ). The shift 8 has a surface 24 against which the triangular lever 17 butts by way of the side 19 . The spring 22 , the triangular lever 17 , the lever 10 , the bearing 7 and the lever 9 form a lifting mechanism 25 . The lifting mechanism 25 assists an operator during opening and closing of the door 5 and also helps retain the door 5 in the open position. For opening purposes, the operator has to overcome the weight 26 (cf. FIG. 1) of the door 5 by the manual force 27 applied by him/her (cf. FIG. 1 ), the operator being assisted here by the spring force 28 (cf. FIG. 1) of the spring 22 .
The functioning of the lifting mechanism 25 is described hereinbelow with reference to FIGS. 1 to 6 . FIGS. 1, 3 , 5 and 2 , 4 , 6 respectively show the door 5 of the dishwasher 1 and the lifting mechanism 1 [sic] in a closed position 29 , in a half-open position 30 and in an open position 31 .
As can be seen from FIG. 5, the weight 26 of the door 5 acts on the bearing 7 with a lever H 1 . The force opposing the weight 26 is applied by the manual force 27 and the spring force 28 .
It can be seen in FIG. 2 that the spring 22 acts on the bearing 7 via the triangular lever 17 and the lever 10 . The spring 22 thus acts on the bearing 7 with an effective lever E 1 since the triangular lever is supported at a point P on the surface 24 of the shaft 8 by way of its side 19 . By virtue of the lever 10 , the triangular lever 17 is blocked such that only joint rotation of the triangular lever 17 with the shaft 8 can take place.
Until approximately the half-open position 30 of the door 5 has been reached, the triangular lever 17 butts against the surface 24 of the shaft 8 by way of the point P, said surface forming a support 24 a for the triangular lever 17 . On the way into the half-open position 30 , the triangular lever 17 rotates jointly with the shaft 8 . This means that the moment by which the spring 22 acts on the bearing 7 remains approximately equal between the closed position 29 and the half-open position 30 since the articulation point 21 of the spring 22 only moves through a small angle on a circular path around the bearing 7 . This means that the effective lever E 2 illustrated in FIG. 4 is only slightly smaller than the effective lever E 1 illustrated in FIG. 2 . By virtue of the rotation of the triangular lever 17 about the bearing 7 , the articulation point 15 of the lever 10 has also been displaced, with the result that the lever A 2 corresponds approximately to the lever E 2 . In the closed position 29 of the door 5 , the lever A 1 was still considerably smaller than the lever E 1 of the triangular lever 17 (cf. FIG. 2 ).
During further displacement of the door 5 into the open position 31 , the lever 10 with its effective lever A 2 then becomes determinative since the point P moves away from the surface 24 of the shaft 8 . This is because the spring 22 then no longer subjects the triangular lever 17 to any moment about the articulation point 15 and it is thus also the case that there is no longer any force which presses the triangular lever 17 onto the shaft 8 at point P.
A variant which is not illustrated provides that the triangular lever 17 butts against the surface 24 of the shaft 8 by way of an articulation indent configured as a recess on the triangular lever 17 . This means that the triangular lever 17 has surface contact with the shaft 8 .
FIG. 6 illustrates the position of the lever mechanism 25 which the latter assumes in the open position 31 of the door 5 . It can be seen that the effective lever A 3 is determined by the lever 10 . This means that the effective lever A 3 has become slightly greater than the effective lever A 2 (cf. FIG. 4) since the lever 10 has moved on a circular path around the bearing 7 between the half-open position 30 and the open position 31 of the door 5 . Comparing FIGS. 2 and 6, it can be seen that, in the closed position 29 of the door 5 , the spring 22 is stressed to a more pronounced extent by a distance LZ 1 +LZ 3 in relation to the open position 31 , this resulting in the door 5 being subjected to a somewhat more pronounced moment in the closed position 29 .
Overall, between the closed position 29 and the half-open position 30 , the lever mechanism 25 brings about a sinusoidal decrease in the effective lever-arm length by means of which the spring 22 acts on the shaft 8 . Between the half-open position 30 and the open position 31 of the door 5 , the lifting mechanism 25 brings about a sinusoidal increase in the effective lever-arm length by means of which the spring 22 acts on the shaft 8 . By virtue of the spring stressing decreasing during the opening operation, the spring 22 acts on the lever mechanism 25 with a decreasable force. Thus, during opening of the door 5 , the shaft 8 is subjected to a moment which, as the door 5 is opened to an increasing extent, decreases slightly to approximately the central position of said door. Between the central position and the open position of the door 5 , the moment acting on the shaft 8 increases again slightly.
FIG. 7 shows a schematic illustration of a variant of the lifting mechanism 25 . Analogously to the lifting mechanism 25 illustrated in FIGS. 1 to 6 , the lifting mechanism 40 illustrated in FIG. 7 likewise has a first lever 9 , a second lever 10 , a bearing 7 and a shaft 8 . The dishwasher 1 has not been illustrated here since the lifting mechanism 40 illustrated in FIG. 7 is likewise provided for the dishwasher 1 illustrated in FIGS. 1, 3 and 6 .
The second lever 10 has a slot 42 which is configured as a guide 41 and in which a bolt 43 is mounted in a displaceable manner. Fastened on the bolt 43 , at an articulation point 43 a, is a tension spring 44 which draws the bolt 43 in the direction of the arrow 45 and is supported in the side part 4 (not illustrated here). Furthermore, the bolt 43 is mounted in a guide 46 , formed in the side part 4 , such that it can be displaced in the vertical direction. Mounting the bolt 43 in the guides 41 and 46 ensures that an effective lever A 10 , by means of which the bolt 43 and the spring 44 act on the shaft 8 via the second lever 10 , remains more or less constant in an angle range 47 . The bolt 43 and the guides 41 , 46 here form a control means 16 .
An exemplary embodiment of the subject matter of the invention which is not illustrated provides for the guide 46 to be of curved design. This makes it possible for the profile of the moment acting on the shaft 8 to be freely determined and adapted to the force profile favorable for an operator.
FIG. 8 shows, by way of the lifting mechanism 60 , a further variant of the lifting mechanism 25 . This lifting mechanism, in turn, has a first lever 9 , a second lever 10 , a bearing 7 and a shaft 8 . The second lever 10 has a cam-like head 61 which exhibits an end side 62 with a rounded surface 63 . On the end side 62 it is possible to see a connecting means 64 which is configured as a band 65 with an end 66 and an end 67 . The band 65 is fastened at an articulation point 68 a with the aid of a fastening means 68 . A spring 69 is articulated at the end 67 of the band 65 . The spring 69 forces the band 65 in the arrow direction 70 and is itself supported in the side part 4 (not illustrated here).
In the case of the lifting mechanism 60 , a force 71 , which the spring 69 exerts on the band 65 in the direction of the arrow 70 , is deflected on the rounded surface 63 of the cam-like head 61 . By virtue of the deflection, the force 71 acts on the fastening means 68 in the arrow direction 72 and thus acts on the shaft 8 with an effective lever All. The effective lever 11 [sic], by means of which the force 71 acts on the shaft 8 , remains constant during rotation of the second lever 10 over an angle range 73 since the force 71 always acts on the fastening means 68 tangentially to the rounded surface 63 . The cam-like head 61 , the connecting means 64 and the band 65 here form a control means 16 .
A further exemplary embodiment which is not illustrated provides for the end side 62 of the cam-like head 61 to be provided with elevations and depressions, with the result that the configuration thereof can influence the lever arm by means of which the spring 69 acts on the shaft 8 . According to the invention, the connecting means is pressed into the depressions of the end side 62 by a mating means.
The invention is not restricted to exemplary embodiments which have been illustrated or described. They also cover the developments of the invention within the context of the claims. | The invention relates to a lifting mechanism for spring-assisted actuation of a covering means of a dishwasher such as a door or shutter, having at least one lever which is mounted on a shaft and is connected to a tension spring. Arranged, in this case, between the lever and the spring is a mechanical control means which brings about a more or less constant lever arm between an articulation point of the spring and the shaft over an angle of rotation of the shaft of up to approximately 100°. | 0 |
FIELD OF THE INVENTION
[0001] The present invention relates to the field of secure communication. The invention has been developed primarily to enable communication between various integrated circuits in a printer, including cartridges for use with the printer, and will be described with reference to this application. However, it will be appreciated that the invention has broad application in the general field, including use in software, hardware and combinations of the two.
CO-PENDING APPLICATIONS
[0002] Various methods, systems and apparatus relating to the present invention are disclosed in the following co-pending applications filed by the applicant or assignee of the present invention simultaneously with the present application:
PLT096US PLT097US PLT098US PLT099US PLT100US
[0003] The disclosures of these co-pending applications are incorporated herein by cross-reference.
RELATED SYSTEMS, METHODS AND DEVICES
[0004] Various methods, systems and apparatus relating to the present invention are disclosed in the following co-pending applications filed by the applicant or assignee of the present invention. The disclosures of all of these co-pending applications are incorporated herein by cross-reference.
[0000]
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6,566,858
6,331,946
6,246,970
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09/517,384
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BACKGROUND OF THE INVENTION
[0005] Manufacturers of systems that require consumables (such as laser printers that require toner cartridges) have addressed the problem of authenticating consumables with varying levels of success. Most have resorted to specialized packaging that involves a patent. However this does not stop home refill operations or clone manufacture in countries with weak industrial property protection. The prevention of copying is important to prevent poorly manufactured substitute consumables from damaging the base system. For example, poorly filtered ink may clog print nozzles in an ink jet printer, causing the consumer to blame the system manufacturer and not admit the use of non-authorized consumables.
[0006] In addition, some systems have operating parameters that may be governed by a license. For example, while a specific printer hardware setup might be capable of printing continuously, the license for use may only authorize a particular print rate. The printing system would ideally be able to access and update the operating parameters in a secure, authenticated way, knowing that the user could not subvert the license agreement.
[0007] Furthermore, legislation in certain countries requires consumables to be reusable. This slightly complicates matters in that refilling must be possible, but not via unauthorized home refill or clone refill means. To authenticate ‘genuine’ consumables, communications between the consumable and the printer can be authenticated with digital signatures. To create a digital signature, the data to be signed (d) is passed together with a secret key (k) through a key dependent one-way hash function (SIG). i.e. signature=SIG k (d). One of the most popular key dependent one-way hash function used today is HMAC-SHA1 (Hash Message Authentication Code—Secure Hash Algorithm No. 1), although any key dependent one-way hash function could be used.
[0008] Consumables such as ink cartridges can have quality assurance integrated circuit devices, or QA chips as they are known, which authenticate the ink cartridge to a corresponding QA chip in the printer before the ink is accepted. The cartridge QA chip stores a secret key and generates a digital signature that the printer QA chip validates before accepting the cartridge.
[0009] A comprehensive description of digital encryption, and the use of encryption keys within the Memjet printing system, is provided in U.S. Pat. No. 7,557,941 entitled “Use of Base and Variant Keys with Three or more Entities”. The entire content of U.S. Pat. No. 7,557,941 is incorporated herein by cross reference.
[0010] To manufacture clone consumables, the authentication process must be subverted. The clone consumable must generate a digital signature that the printer will validate. This requires the secret key stored in the cartridge. The QA chip may be ‘attacked’ in an effort to decrypt the key. One category of attacks is known as side channel attacks. These attacks exploit information ‘leaked’ from the chip during operation. The power consumption, the emitted electro-magnetic radiation and other externally observable fluctuations can provide information about the operations of the chip.
[0011] One particular type of side-channel attack is the differential power analysis attack (or DPA attack) which focuses on the power consumption of the chip. The power consumption is easily measurable and indicates the number of changes in state for the various logic components. Typically, correct bits within the signature cause many logic states to change and so the power spikes. Recording and analysing many (say 100 to 1000) traces of the power consumption in response to messages sent by the attacker can reveal the secret key. In light of this, DPA attacks are particularly inexpensive and practical.
[0012] Once in possession of the secret key, clone cartridges are indistinguishable from the attacked authorized cartridge. All printers that accept the authorized cartridge will now also accept the clones. It is desirable to have a QA device with a DPA defence that frustrates an attacker or reduces the harm caused encryption keys are successfully acquired.
SUMMARY OF THE INVENTION
[0013] According to a first aspect, the present invention provides a device for encrypted communication with external entities, the device comprising:
[0014] a first memory;
[0015] an encryption key stored in the first memory; and,
[0016] a one-way function for application to the encryption key; wherein during use,
[0017] the encryption key is retrieved from the first memory prior to application to the one-way function and the device is configured to limit the number of times the encryption key is allowed to be retrieved from the first memory to a pre-determined threshold.
[0018] Preferably, the encryption key is a base key and the first memory is a non-volatile memory. Optionally, the encryption key is a batch key used for securing an initial configuration procedure of the device.
[0019] A DPA attack needs a certain number of power traces during retrieval and use of the base key in order to deduce its identity. By limiting the number of times that the base key can be accessed, an attacker has insufficient information to analyse and determine the base key.
[0020] Preferably, the device is configured to generate a first variant key based on the one-way function, the base key and unique information from a first external entity, the first variant key being stored for generating a digital signature to authenticate communications between the device and the first external entity.
[0021] The first variant key is retrieved and used to generate a digital signature for every communication with the first external entity. A DPA attack can acquire a sufficient number of power traces to analyse the first variant key, but as this key will only authenticate communication with the first external entity, it is of little value to the attacker. Clone cartridges using this key will work with one printer only.
[0022] Preferably, the device further comprises a rewritable memory for storing the first variant key, the rewritable memory having capacity to store a predetermined number of variant keys generated using the base key, the predetermined number of variant keys being less than the threshold number of times that the base key can be retrieved from the non-volatile memory.
[0023] A user may legitimately want to share an ink cartridge between two or three printers. The cartridge will need to retrieve the base key from non-volatile memory at least three times to generate the variant keys for the respective printers. However if the cache memory can store three variant keys, the QA chip will not reach the base key retrieval limit if the cartridge is swapped between the user's printers numerous times. A DPA attacker can potentially determine all three variant keys, but this still only limits any clone cartridge to use with three printers which is not commercially worthwhile.
[0024] Preferably, the generation of each of the variant keys using the one-way function is a calculation that has several separate terms, and the device is configured to use random arrangements of the terms. This frustrates the attacker by making it harder to combine multiple power consumption waveforms to reduce noise.
[0025] Optionally, the generation of each of the variant keys using the one-way function is a calculation that has several separate terms, and the device is configured to provide an arrangement of the terms that differs from other like devices.
[0026] Preferably, the device further comprises a set of masking numbers, wherein during use, the generation of each of the variant keys using the one-way function is a calculation that has several separate terms and at least one of the masking numbers of added as an additional term, and subsequently subtracted from the result of the calculation. A set of masking numbers is unpredictable to the attacker and it will change the power consumption waveform but not affect the final cryptographic result.
[0027] Optionally, the masking numbers are randomly generated for the generation of each of the variant keys.
[0028] Preferably, the device disallows the base key to be retrieved for generating a digital signature. In a further preferred form, the base key can be retrieved only for generating a variant key.
[0029] Preferably, the device further comprises resource data wherein the first external entity has certain permissions in relation to operations on the resource data.
[0030] Optionally the resource data represents a physical property.
[0031] Optionally the physical property is a remaining amount of a physical resource.
[0032] Optionally the resource is a consumable resource.
[0033] Optionally the resource entity is physically attached to a reservoir or magazine that holds the consumable resource.
[0034] Optionally the resource is a fluid.
[0035] Optionally the fluid is ink.
[0036] Optionally the operation includes a read, in which the resource data is read by the first external entity.
[0037] Optionally the operation includes write, in which the resource data is modified by the entity making the request.
[0038] Optionally the operation includes decrementing, in which the resource is decremented by the entity making the request.
[0039] Optionally the one way function is a hash function.
[0040] Optionally the one way function is SHA1.
[0041] According to a second aspect, the present invention provides a device for encrypted communication with external entities, the device comprising:
[0042] a first memory;
[0043] an encryption key stored in the first memory; and,
[0044] a one-way function for application to the encryption key; wherein during use,
[0045] the encryption key is retrieved from the first memory prior to application to the one-way function and the device is configured to limit the number of times the encryption key is allowed to be retrieved from the first memory in a given period of time.
[0046] Preferably, the encryption key is a base key and the first memory is a non-volatile memory. Optionally, the encryption key is a batch key used for securing an initial configuration procedure of the device.
[0047] In this aspect, legitimate users can swap a cartridge between printers an unlimited number of times, as long as it is not too frequent. However, the DPA attacker would find the retrieval frequency limit too frustratingly slow for gaining the many power traces needed to successfully deduce the encryption key.
[0048] According to a third aspect, the present invention provides a system for encrypted communication between entities, the system comprising:
[0049] a device with an encryption key stored in memory;
[0050] an external entity with identity data for transmission to the device to initiate communication such that in response the device applies a one way function to the encryption key and the identity data to generate a variant key used to authenticate communications between the device and the external entity; wherein,
[0051] the device is configured to limit the number of times the encryption key is allowed to be retrieved from the first memory to a pre-determined threshold.
[0052] According to a fourth aspect, the present invention provides a system for encrypted communication between entities, the system comprising:
[0053] a device with an encryption key stored in memory;
[0054] an external entity with identity data for transmission to the device to initiate communication such that in response the device applies a one way function to the encryption key and the identity data to generate a variant key used to authenticate communications between the device and the external entity; wherein,
[0055] the device is configured to limit the number of times the encryption key is retrieved from the first memory in a given period of time.
[0056] Preferably the encryption key is a base key and the first memory is a non-volatile memory.
[0057] Preferably the identity data is a unique identifier that identifies the external entity to the exclusion of all other external entities such that the variant key generates a digital signature to authenticate communications between the device and the external entity only.
[0058] Preferably the device further comprises a second memory for a plurality variant keys generated for digital signatures to authenticate communication with a plurality of external entities respectively.
[0059] Preferably the second memory is a rewritable memory for storing a predetermined number of the variant keys, the predetermined number of variant keys being less than the threshold number of times that the base key can be retrieved from the non-volatile memory.
[0060] Preferably the generation of each of the variant keys using the one-way function includes adding several separate terms, and the device is configured to use random arrangements of the terms.
[0061] Preferably the generation of each of the variant keys using the one-way function includes adding several separate terms, and the device is configured to provide an arrangement of the terms that differs from other like devices.
[0062] Preferably the one-way function used to generate the variant keys includes adding several separate terms together, the device being configured to add a masking number as an additional term to the one way function, and subsequently subtract the masking number from the sum of the calculation.
[0063] Preferably the masking number is randomly generated for the generation of each of the variant keys.
[0064] Preferably the base key can be retrieved only for generating a variant key.
[0065] Preferably the device stores resource data wherein the external entity has certain permissions in relation to operations on the resource data.
[0066] Preferably the resource data represents a physical property.
[0067] Preferably the physical property is a remaining amount of a physical resource.
[0068] Preferably the operations include a read operation in which the resource data is read by the first external entity.
[0069] Preferably the operations include a write operation, in which the resource data is modified by the entity making the request.
[0070] Preferably the write operation is decrementing the resource data as an indication of consumption of the physical resource.
[0071] Preferably the one way function is a hash function.
[0072] Preferably the hash function is SHA1.
[0073] Preferably the device is incorporated into an ink cartridge.
[0074] Preferably the external entity is a print engine controller (PEC) in an inkjet printer configured for use with the ink cartridge.
[0075] According to a fifth aspect, the present invention provides a method of encrypted communication between entities, the method comprising the steps of:
[0076] providing a device with an encryption key stored in memory;
[0077] providing an external entity with identity data for transmission to the device;
[0078] applying a one way function to the encryption key and the identity data to generate a variant key;
[0079] authenticating communications between the device and the external entity with the variant key; and,
[0080] limiting the number of times the encryption key is retrieved from the first memory to a pre-determined threshold.
[0081] According to a sixth aspect, the present invention provides a method of encrypted communication between entities, the method comprising the steps of:
[0082] providing a device with an encryption key stored in memory;
[0083] providing an external entity with identity data for transmission to the device;
[0084] applying a one way function to the encryption key and the identity data to generate a variant key;
[0085] authenticating communications between the device and the external entity with the variant key; and,
[0086] limiting the number of times the encryption key is retrieved from the first memory in a given period of time.
[0087] Preferably the encryption key is a base key and the first memory is a non-volatile memory.
[0088] Preferably the identity data is a unique identifier that identifies the external entity to the exclusion of all other external entities and the step of authenticating communications comprises generating a digital signature with the variant key for attachment to communications between the device and the external entity only.
[0089] Preferably the method further comprises the step of providing a second memory in the device for a plurality variant keys generated for digital signatures to authenticate communication with a plurality of external entities respectively.
[0090] Preferably the second memory is a rewritable memory for storing a predetermined number of the variant keys, the predetermined number of variant keys being less than the threshold number of times that the base key can be retrieved from the non-volatile memory.
[0091] Preferably the step of generating each of the variant keys using the one-way function includes an adding several separate terms, and the device is configured to use random arrangements of the terms.
[0092] Preferably the step of generating each of the variant keys using the one-way function includes adding several separate terms, and the device is configured to provide an arrangement of the terms that differs from other like devices.
[0093] Preferably the one-way function used to generate the variant keys includes adding several separate terms together, the device being configured to add a masking number as an additional term to the one way function, and subsequently subtract the masking number from the sum of the calculation.
[0094] Preferably the masking number is randomly generated for the generation of each of the variant keys.
[0095] Preferably the base key can be retrieved only for generating a variant key.
[0096] Preferably the method further comprises the step of storing resource data in the device and providing the external entity with certain permissions in relation to operations on the resource data. Preferably the resource data represents a physical property. Preferably the physical property is a remaining amount of a physical resource. Preferably one of the permissions is a read operation in which the resource data is read by the external entity. Preferably the operations include a write operation, in which the resource data is modified by the entity making the request. Preferably the write operation is decrementing the resource data as an indication of consumption of the physical resource.
[0097] Preferably the one way function is a hash function. Preferably the hash function is SHA1.
[0098] Preferably the method further comprises the step of incorporating the device into an ink cartridge. Preferably the external entity is a print engine controller (PEC) in an inkjet printer configured for use with the ink cartridge.
BRIEF DESCRIPTION OF THE DRAWINGS
[0099] Preferred embodiments of the invention will now be described by way of example only with reference to the accompanying drawings, in which:
[0100] FIG. 1A is a sample QA chip power trace;
[0101] FIG. 1B is a covariance plot revealing data dependent power spikes;
[0102] FIG. 2 is a system diagram of the encrypted communication between the printer and the QA chip;
[0103] FIG. 3 is a system diagram of a typical use scenario of an ink cartridge with a QA chip according to the invention;
[0104] FIG. 4 is a system diagram of a more complicated use scenario;
[0105] FIG. 5 is a flowchart of the method steps involved in the system shown in FIG. 2 ;
[0106] FIG. 6 is a flowchart of the method steps involved in the system shown in FIG. 3 ; and,
[0107] FIG. 7 is a flowchart of the method steps involved in the system shown in FIG. 4 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0108] Particular embodiments of the invention will now be described with reference to the Applicant's Memjet™ printing system. However, the skilled worker will understand that the invention is not restricted to use in a printing system and may be employed in a wide range of applications requiring encrypted communication and authentication of related entities.
Side Channel Behaviour of Prior Art QA Chip
[0109] The invention builds on the key management mechanisms presented in U.S. Pat. No. 7,557,941 cross referenced above and therefore adheres to the same terminology. Each ink cartridge in a Memjet™ Printer contains a QA (Quality Assurance) Chip that stores and uses a valuable base key to authenticate itself to software running in the Print Engine Controller (SOPEC) chip. Compromise of this key would allow an attacker to build clone ink cartridges that are accepted by any printer of the appropriate model.
[0110] The prior art or unimproved QA Chip will, in response to an attacker's command, retrieve a base key and use it for the following purposes:
to check the signature of an incoming command; to sign some data requested in an authenticated read; to form a variant key (see U.S. Pat. No. 7,557,941).
[0114] There is effectively no limit on the number of times that an attacker can ask for these commands to be processed.
[0115] Side-channel analysis attacks can repeatedly observe QA Chip outputs such as power consumption, emitted light, and emitted radio frequency emissions during the use of the base key and potentially deduce the key value. These QA Chip outputs are not intended by the designer as outputs, but they can often be used by an attacker.
Differential Power Analysis Attacks on the QA Chip
[0116] The following observations relate to one of the possible side-channel attacks on the unimproved QA Chip—Differential Power Analysis (DPA). This is a typical sequence of steps that would be used to attack the QA Chip with DPA.
1. The first step in a differential power analysis attack is to record the power consumption of the attacked QA Chip while it processes many known, different data values, probably input values. In this step, the attacker gets measured power consumption values, which depend at least partially on the used secret key. The attacker needs to capture say 1000 power traces at the beginning. FIG. 1A shows a sample power trace 1 of an unimproved QA chip. 2. Then, with the known data values and a guess for a part of the secret key (e.g. 4 bits of it), the power consumption values are partitioned into two groups according to whether some intermediately computed value is expected to cause the QA Chip to consume more power or less power. The intermediately computed value is typically bits of the QA Chip accumulator, following a logical or arithmetic instruction involving the selected part of the secret key and other data known to the attacker. 3. Each partition above forms a hypothesis for some guess of part of the secret key. The hypothesis is tested to see if it is correct by statistical measures that analyse the difference of average power consumption between the two partitions. For the correct key guess, the statistical measure should reveal a “spike”, and for the incorrect key guess, the measure should be flat. FIG. 1B shows the covariance plot 2 which reveals the data dependent power spikes 3 . 4. The attacker then simply continues the attack in the same way for the other parts of the secret key.
[0121] More complex attacks are also possible, and these could reduce the required number of power consumption traces.
[0122] For an authenticated read command (see U.S. Pat. No. 7,557,941), the attacker can control the following things to help produce useful DPA results during the HMAC-SHA1 operation:
checker's nonce “RC” (160 bits) field selection to be read (the field selection is potentially large) field values (by decrementing or writing to them first).
[0126] This amounts to a large amount of attacker control, almost certainly sufficient to produce useful DPA results for a 160 bit base key. During the generation of a variant key from a base key (see U.S. Pat. No. 7,557,941), the attacker can control the checker QA Device identifier ChipID (64 bits) to help produce useful DPA results during the SHA-1 operation.
[0127] An informed attacker would probably ask the Ink Cartridge QA Chip to sign authenticated read values with the base key, because the base ink access key is much more valuable than a variant key.
Typical Use Profiles for the Ink Cartridge QA Chip
[0128] From knowledge of typical printer use cases, there is a high probability that the following parameters will be true for the ink cartridge QA Chip.
1. A single-use ink cartridge will operate in a few printers at most. 2. A refillable ink cartridge need only work in say 10 different printers over the life of the cartridge, or a few printers for each refill. This assumes that ink cartridges will only be refilled say 5 times due to mechanical wear and tear.
The Basic Side-Channel Defence—Variant Key Caching
[0131] The side-channel defence introduces caching of generated variant keys, and to constrain the ink cartridge QA Chip in three ways:
1. Only allow a small number of variant keys to be generated over the life of the QA Chip. This means that the valuable base key is only accessed a few times over the whole life of each ink cartridge QA Chip. Once a variant key has been calculated, it is cached for later use. 2. Restrict the ink cartridge QA Chip to only generate or check signatures based on variant keys. 3. Restrict the number of times that the batch keys present in an unconfigured QA chip can be used, and therefore prevent a DPA attack on these keys. Batch keys are described in more detail below.
[0135] FIG. 2 diagrammatically illustrates the communication between a first printer 12 and the QA chip 4 during normal use. FIG. 5 is a flowchart 100 showing the steps followed by the first printer 12 and the cartridge 13 to authenticate communications between the two. Firstly, the cartridge 13 is installed in the first printer 12 (step 102 ). The first printer asks for a valid key and the QA chip 4 checks for one in the cache 9 (step 104 ). If no variant key is cached, the QA chip 4 checks the number of times the base key 17 has been retrieved (step 106 ), or alternatively, the number of base key retrievals within a certain period of time. If the number of base key retrievals exceeds the maximum—in this case five—base key retrieval is refused (step 108 ) and the cartridge can not be used with the printer 12 .
[0136] To authenticate itself to the first printer 12 , the QA chip 4 retrieves the base key 17 stored in non-volatile memory 5 . Using a one way function 6 such as SHA1, a first variant key 18 is generated using the base key 17 , and unique information from the first printer 12 such as the chip ID 16 identifying the printer's PEC 20 (step 110 ). The first variant key 18 is stored in cache memory 9 (step 116 ) and used to digitally sign 8 and authenticate data such as field data 7 transmitted to the first printer 12 (step 118 ). The digital signature 8 generated with the first variant key 18 will only be validated by the first printer 12 . Communications with other printers will require the generation of further digital signatures based on those printer's unique ID's.
[0137] In the event that the cache memory 9 is full (step 112 ), the cached key that has not be used for longest period of time is overwritten in favour of the newly generated variant key (step 114 ).
[0138] Commands 11 from the first printer 12 are likewise validated by the QA chip 4 so that field data 7 such as virtual ink supplies can be read and decremented during operation with the printer. All authentication between the first printer 12 and the QA chip 4 being based on the first variant key 18 such that the base key 17 is retrieved once only.
[0139] The side channel defence of the present invention is unlikely to interfere with legitimate uses of a cartridge 13 . FIG. 3 shows a typical use scenario in which the QA chip 4 follows the steps set out in the flowchart 120 of FIG. 6 . It is conceivable that a user would want to swap an ink cartridge 13 out of a first printer 12 and into a second printer 14 (step 122 ). Initially the QA chip 4 in the cartridge 13 has permission to retrieve a base key a maximum of five times. When installed in the first printer 12 on the 6 th of the month (step 102 of FIG. 5 ), the QA chip 4 in the cartridge 13 authenticates itself by retrieving the base key 17 , the first printer ID 16 and generating a first variant key 21 . This uses up one of the base key retrieval permissions which now reduce to four. The variant key 21 is stored in cache memory 9 and used for digitally signing data sent to the first printer 12 (as per the basic usage scenario described in FIGS. 2 and 5 ).
[0140] On the 9 th of the month, the user removes the cartridge 13 from the first printer 12 and installs it into the second printer 14 (step 122 ). The second printer 14 has a different ID so it does not validate digital signatures generated using the first variant key 21 (step 124 ). The number of base key retrievals is less than five (step 126 ) so retrieval of the base key 17 is permitted (step 130 ). A new variant key 22 is generated using the base key and the unique ID of the second printer 14 (step 132 ). Retrieving the base key uses another of the five retrieval permissions which now drops to three. However, the cache memory 9 now stores both the first variant key 21 and the second variant key 22 (steps 134 and 138 ).
[0141] The communication between the second printer 14 and the QA chip 4 is authenticated by retrieving the second variant key (step 140 ) to digitally sign transmitted data (step 142 ).
[0142] On the 10 th of the month, the user returns the cartridge 13 to the first printer 12 (step 144 ). As the first variant key 21 is still cached (step 104 ), the base key does not need to be retrieved and the number of base key retrieval permissions remains at three. The first variant key 21 is still able to generate digital signatures that the first printer 12 will validate (step 118 of FIG. 5 ).
[0143] FIGS. 4 and 7 depict a more complicated use scenario that is relatively unlikely but still conceivable. In this case, the user installs the cartridge in a third printer 15 on the 10 th of the month (step 162 ). The cartridge 13 has not previously been installed in the third printer 15 , so a suitable variant key does not exist (step 164 ). To generate a third variant key 23 , the base key 17 is once again retrieved and the number of remaining base key retrieval permissions reduces to two (steps 166 and 170 ). The third variant key 23 is generated (step 172 ) by applying the hash function to the base key 17 and the chip ID for the third printer 15 . As the cache 9 only has capacity to store two variant keys (step 174 ), the least recently used key—the first variant key 21 —is overwritten (step 176 ) and the third variant key 23 is cached (step 178 ). The cartridge 13 is used in the third printer 15 for eight days using the third variant key 23 to authenticate communications (steps 180 and 182 ).
[0144] On the 18 th of the month, the user yet again installs the cartridge 13 in the second printer 14 (step 184 ). Fortunately, the second variant key 22 is still cached (step 124 ) and so the number of base key retrieval permissions remains at two. Usage proceeds in accordance with step 142 of flowchart 120 in FIG. 6 . However, on the 26 th of the month, the cartridge 13 is returned to the first printer 12 (step 186 ) and as the first variant key 21 was overwritten to cache the third variant key 23 (step 104 of flowchart 100 in FIG. 5 ), the base key 17 must be retrieved to again generate the first variant key 21 . The QA chip proceeds according to the steps 106 onwards shown in flowchart 100 . In this instance, the third variant key 23 is now the least recently used variant key in the cache 9 and so it is overwritten in favour of the first variant key 21 (steps 112 and 114 ). This leaves the cartridge 13 with only one remaining base key retrieval permission. However, after multiple uses in three different printers, it is unlikely that the cartridge 13 has much, if any ink left.
[0145] If the ink capacity is high or the cartridge is refillable, the QA chip can be configured to limit the rate that the base key retrieved from the non-volatile memory. For example, the maximum number of retrievals may apply to a predetermine period only (say each calendar day), after which, any used retrieval permissions are ‘re-credited’ for the next predetermined period.
[0146] An attacker can potentially conduct DPA attacks on the small number of generated variant ink access keys using a single ink cartridge, but this would only compromise a small number of printers. Furthermore, if the required variant keys are present in less secure parts of the system, an attacker would probably attack elsewhere in preference to the QA Chip.
[0147] For an attacker to conduct a DPA attack on a valuable base key, they will need to collect power consumption waveforms from many ink cartridges. For example, assuming 1000 compatible power consumption waveforms are required to complete a DPA attack, and each ink cartridge is allowed to generate 3 variant keys for each base key, then the attacker would need at least 333 ink cartridges.
[0148] It will be appreciated that the invention does not prevent DPA attacks. The goal is to make DPA too burdensome or economically unappealing for potential attackers.
[0149] In summary, the improved QA Chip can still generate an effectively unlimited number of useful signatures as required in a printer system, but with a significantly lower vulnerability to DPA attacks.
Batch Keys and Configuration
[0150] Batch keys are placed into QA Chips when the chips are tested, to help secure the later configuration process. Before configuration, the QA Chips are generic, and can be used to make printer components of different brands and models.
[0151] The configuration process securely loads into a QA Chip the cryptographic keys and fields required for a particular printer component, e.g. a Brand X cyan ink cartridge. Batch keys are used to encrypt all other keys in their transport to the QA chip during configuration. The configuration process usually takes place in the physically secure printer component factory.
[0152] It is necessary to prevent the compromise of a batch key because this could lead to compromise of one or more base keys. Batch keys are variant keys, so DPA attacks cannot combine power waveforms from multiple QA Chips.
Variant Key Generation and SHA1
[0153] Variant keys are created by feeding the 160-bit base key and the 64-bit QA Device identifier ChipID into the well-known SHA1 secure hash algorithm. SHA1 secure hash algorithm is well known and widely used. A detailed explanation of the operation of this algorithm is provided by Wikipedia contributors, SHA hash functions, accessed 7 Aug. 2009 (see http://en.wikipedia.org/wiki/SHA_hash_functions)
Static Arrangement of Terms
[0154] The improved QA Chip can incorporate random arrangements of the terms of SHA1 calculations when performing variant key generation. This would make it harder for an attacker to combine multiple power consumption waveforms to reduce noise.
[0155] A first implementation is for an individual QA Chip to have a static arrangement of terms for each SHA1 calculation. In other words, an individual QA Chip would not change the order of its terms over time. Each QA Chip would have one of several possible arrangements of terms for each SHA1 calculation. The term arrangements would be selected randomly when the chip is programmed with the QA Chip application. Given the variant key generation limitations, this simple approach should still provide a useful benefit, because it should force the attacker to acquire a larger number of ink cartridges to successfully attack a base key.
[0156] As an example of the implementation of this improvement, consider the calculation of a state word A in the manner set out in http://en.wikipedia.org/wiki/SHA_hash_functions.
[0000] temp=(a leftrotate 5)+ f+e+k+w[i]
[0000] (Note that temp is later assigned to a.)
[0157] This equation involves the addition of 5 terms. These additions could be done in any of 120 different orders and still get the same arithmetic result. However, each individual QA Chip would only add these terms in a fixed order.
[0158] A bigger problem with this example from the defender's perspective is that the attacker would know that only ‘a’ is being left-rotated. To address this, the improved QA Chip can perform a number of left-rotates of other data that varies with different inputs, and rearrange the order of these left-rotates in different chips.
[0159] The SHA1 implementation used for unlimited operations, such as HMAC-SHA1 signing using variant keys, should be different so it cannot be easily studied by an attacker to learn about the SHA1 implementation used for variant key generation. Therefore an improved QA Chip employing static term arrangement must have two different implementations of SHA1 within it.
Addition of Static Masking Operations
[0160] The addition of masking operations involves:
the insertion of a set of mask numbers, unpredictable for an attacker, into each instance of an improved QA Chip—note that these numbers do not change once programmed into an individual QA Chip; the modification of cryptographic calculations in the QA Chip to use these unpredictable numbers to change power consumption waveforms in a manner that changes power consumption waveforms but does not affect the final cryptographic result;
[0163] For example, if the cryptographic operation involves adding a set of terms:
[0000] temp=(a leftrotate 5)+ f+e+k+w[i]
[0000] . . . then the addition of simple masking operations may be (for example):
adding one of the unpredictable mask numbers m to the first term; completing the additions as per the standard algorithm; and finally; subtracting m from the final sum.
[0167] In other words, assuming left-to-right additions, the equation is modified to:
[0000] temp= m +(a leftrotate 5)+ f+e+k+w[i]−m
[0168] Similar approaches can be used for the other calculations involved in the SHA1 operation used to calculate a variant key. For example, masking techniques for nonlinear bitwise Boolean operations such as in:
[0000] f =( b and c ) or ((not b ) and d )
[0169] The power consumed in a CMOS arithmetic logic unit (ALU) depends on the number of changed bits rather than the operation result, so the ALU power consumption waveform for each chip will be different, even though the calculated results are the same. This will make it harder for an attacker to usefully combine the ALU power consumption waveforms from multiple chips to perform a DPA attack on a base key.
[0170] One advantage of masking over term re-arrangement is that the number of QA Chips with different power consumption waveforms would be very large. The number of possible rearrangements of terms is relatively small.
[0171] Masking usually involves the use of a source of random data within one chip to provide a dynamic mask value. A dynamic mask value should not be required for the improved QA Chip because only a small number of power consumption waveforms can be obtained from each QA Chip.
Addition of Dynamic Term Arrangement
[0172] In some circumstances, there may be benefits for DPA defence in dynamic term arrangement, meaning that the improved QA Chip randomly arranges the order of calculation of terms for each successive variant key generation in a single chip.
[0173] The benefits are most relevant if the allowed number of variant key generations is necessarily high because of the particular circumstances in which the QA Chip is being applied, or if the other constraints listed in http://en.wikipedia.org/wiki/SHA_hash_functions cannot be enforced.
Addition of Dynamic Masking Operations
[0174] One dynamic masking operation involves the improved QA Chip randomly generating masking values ‘m’ for each successive variant key generation in a single chip. The masking values would be applied as described for the addition of static masking operations. As with dynamic term arrangement (described above), the benefits are most relevant when the allowed number of variant key generations is relatively high in order to provide sufficient flexibility for some application, or if the other constraints listed in http://en.wikipedia.org/wiki/SHA_hash_functions cannot be enforced.
[0175] Masking can potentially be defeated by higher order DPA attacks. Since higher order DPA attacks require more power consumption waveforms than basic DPA attacks, dynamic masking can still be of some advantage.
Additional Benefits of the Defences
[0176] While the described defences improve resistance to a range of side-channel attacks, they also reduce the QA Chips vulnerability to a range of other physical attacks such as focused ion beam chip modifications. This is because if the base key value only moves from the non-volatile memory cell into other circuitry very few times over the life of the ink cartridge, then very little key information can practically be obtained for each difficult chip modification/probing. It is very difficult to directly measure the electrical charge on a tiny non-volatile memory cell containing a key bit unless it is read from the memory.
Additional Command for Setting QA Device Identifier
[0177] An additional set_QA_Device_ID command can be added to make the use of base keys more explicit. This command would:
communicate the appropriate QA Chip identifier for the checking device, for a selected base key or set of base keys; cause the calculation of one or a set of variant keys; and cause the caching of the variant key(s) for later use.
Restricting Variant Key Generations with a Virtual Consumable
[0181] The number of variant key generations allowed in the improved QA Chip can be restricted by using a virtual consumable (VC). A virtual consumable is a QA Chip field that indicates the remaining amount of some resource, and which is securely decremented during printer operation as the resource is consumed.
[0182] This approach has the following advantages:
an authorised refill machine refills the number of allowed variant key generations in the same way that it refills virtual ink; the QA Chip does not need to be restricted to a predetermined maximum number of variant key generations required over many refills.
[0185] The invention has been described herein by way of example only. Ordinary workers in this field will readily recognise many variations and modification which do not depart from the spirit and scope of the broad inventive concept. | A device for encrypted communication with external entities is configured to frustrate side channel attacks attempting to determine an encryption key. The device has a first memory, an encryption key stored in the first memory and a one-way function for application to the encryption key. During use, the encryption key is retrieved from the first memory prior to application to the one-way function and the device is configured to limit the number of times the encryption key is allowed to be retrieved from the non-volatile memory to a pre-determined threshold. | 7 |
CROSS REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of Provisional Patent Application Ser. No. 61/292,249 filed Jan. 5, 2010, titled CONCENTRIC AIR DIFFUSER WITH AN ANGLED SUPPLY AIR FACE which is hereby incorporated in its entirety.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of an exemplary embodiment of the invention;
FIG. 2 is a top view of an exemplary embodiment of the invention shown in FIG. 1 ;
FIG. 3 is a side view of an exemplary embodiment of the invention shown in FIG. 1 ;
FIG. 4 is a perspective view of an exemplary embodiment of the invention;
FIG. 5 is a side view of an exemplary embodiment of the invention shown in FIG. 4 ;
FIG. 6 is an exploded perspective view of an exemplary embodiment of the invention illustrating interior components;
FIGS. 7A and 7B form an exploded perspective view of an exemplary embodiment the invention illustrating interior components;
FIG. 8 is an exploded perspective view of an exemplary embodiment of the invention illustrating interior components.
BRIEF SUMMARY OF THE INVENTION
In one aspect, apparatus is provided that includes a four sided ceiling pass-through support structure and an angled air exchange structure wherein an air inlet portion is substantially co-planer with the ceiling and at least one air outlet portion is angled with respect to the air inlet portion at an angle other than 90 degrees.
In another respect, a method is provided that includes providing an inner surround structure that channels ingoing air of an air exchange system, providing an air diffuser, providing a smoke detector including a sampling tube, providing an outer surround structure that channels outgoing air of the air exchange system, and mounting the smoke detector to the diffuser such that a sampling tube of the detector extends into the inner surround structure and the sampling tube is accessible through a single access door in the inner surround structure.
In yet another aspect, apparatus is provided that includes a bidirectional airflow device configured to simultaneously direct both incoming air and outgoing air and one or more baffles placed inside the bidirectional airflow device, the baffles positioned and sized such that outgoing air is substantially balanced between a plurality of outgoing air diffusers.
DETAILED DESCRIPTION OF THE INVENTION
The following detailed description is of the best currently contemplated modes of carrying out exemplary embodiments of the invention. The description is not to be taken in a limiting sense, but is made merely for the purpose of illustrating the general principles of the invention, since the scope of the invention is best defined by the appended claims.
Broadly, an embodiment of the present invention generally is a concentric air diffuser with an angled supply air face.
Typical concentric air diffusers can be flat faced and square drop box types. The instant concentric air diffuser can provide a less limited amount of face area and increased adjustability of throw for supply air to be delivered. With a larger face area, there are less restrictions, noise, and room for a pre-manufactured adjustable air throw device. The instant diffuser can have an angled face that can allow for a larger face area compared to a flush mount diffuser with a completely flat face. The instant diffuser also can allow for the use of off-the-shelf supply air diffusers with adjustable blades that allow for adjusting air flow distribution and balancing. The angled face can also be more cosmetically appealing than a drop box square type concentric air diffuser.
Typical devices can have a flat face with limited space for supply air dispersion. The flat face diffuser can also have limited or no adjustment to the supply air distribution. The drop box (square) concentric that is typically available may not blend into a ceiling as well as the instant angled face diffuser. The instant angled face diffuser may not project below the ceiling as much as other drop box concentric diffusers do.
Now referring to FIGS. 1-4 , an exemplary embodiment of the instant device ( 10 ) comprises the following elements. A plurality of exterior sides ( 14 ) that can be made from, for example but not limited to, 24 gauge sheet metal. As is universally known, 24 gauge sheet metal is non permeable to air. As are other typical materials used for fabricating air handling devices such as air ducts (both hard and flexible) for example. The exterior sides ( 14 ) can be insulated with, for example, R-8 duct liner insulation that is glued and pinned. The exterior sides ( 14 ) can have four equal sides. The sides ( 14 ) can be bent up accordingly and locked together with, for example but not limited to a Pittsburgh lock. Instead of Pittsburgh locks, any known attachment methods such as Snap locks, or ⅛″ rivets can be employed. The top ( 36 ) can also be constructed of, for example but not limited to, 24 gauge sheet metal. The top ( 36 ) can have round or rectangular inlets for the supply and return. A center return air straight duct ( 22 ) and a center return air duct transition ( 24 ) can be constructed of, for example but not limited to, 24 gauge sheet metal. A deflector can be positioned between the return air section and the supply air section and can be attached to the center return air straight duct ( 22 ) and sides ( 14 ). A center return air grill ( 18 ) can use, for example but not limited to, a pre-fabricated aluminum egg crate grille. The four supply air diffusers ( 16 ) can be pre-manufactured by a diffuser manufacturer that sells grills and diffusers. The supply air diffusers are off the shelf items, not specifically manufactured for the instant device ( 10 ). The supply air diffusers can be diffusers with adjustable air deflectors that can be adjusted to balance outgoing air flow. Alternatively as better explained below, the supply air diffusers can be prefabricated adjustable diffusers where to achieve a substantially balanced air flow, a plurality of baffles are employed. The round inlet holes (not shown) can use a 4″ high round collar that can be fastened and sealed to the top ( 36 ) or smoke pan ( 72 ). A 2″ high rectangular collar can be used in lieu of round collars if chosen. Two air diverters ( 78 ), can be installed in the supply air section of the concentric diffuser, opposite of each other, before the top ( 36 ) is installed.
The four sides ( 14 ) can be bent up to make the exterior shell. The four sides ( 14 ) can be run through a Pittsburgh lock machine and then locked together. The four face ( 12 ) pieces can be bent at approximately a 27 degree angle or at similar angles and secured together with ⅛ inch rivets. The sides ( 14 ) can be insulated with the exemplary R-8 duct liner that is secured with glue and pins.
The face ( 12 ) is then attached to the sides ( 14 ) using four trim pieces ( 70 ) with ⅛ inch rivets or a similar manner.
The center return air straight duct ( 22 ) can be fabricated and then connected to the face ( 12 ). This can be connected with ⅛ inch rivets or a similar manner. The center return air transition ( 24 ) can be fabricated and then connected to the center straight duct ( 22 ) with “S” cleats ( 86 ) and screws.
The two air diverters ( 78 ) can be fabricated, formed, and then installed in the supply air section of the device. This allows for interior air distribution around the rear side of the return air duct transition units ( 22 , 24 ). The baffle ( 84 ) is fabricated and attached to the sides ( 14 ).
The top ( 36 ) can be placed on top after the side flanges are bent. The top ( 36 ) can have either round or rectangular inlets. The top ( 36 ) can be insulated with, for example, R-8 R value duct liner. The top ( 36 ) can be attached with rivets and sealed as well.
All face ( 12 ) seams can be caulked. The face can be typically painted white. The four supply air diffusers can be installed in the face ( 12 ) with screws as well as the inlet and outlet collars ( 74 ) can be installed in the top ( 36 ) with screws or tabs and then sealed with caulk.
The instant device is described as a complete supply and return air diffuser device for a fan powered heating, ventilating, and air-conditioning (HVAC) unit. However, if non-fan units exist currently or are later developed, then the benefits of the invention would accrue to such non-fan type units. When connected to a fan powered HVAC unit, the device can supply to and return air from a desired space. The device can supply a desired amount of air outward, away from the device through its four angled faces ( 12 ). The angled faces ( 12 ) sit below the existing ceiling if the device is installed in an area with a ceiling. The device may be designed to be installed in many different ceiling applications, including t-bar lay in types. The center of the device can take air in through the eggcrate center of the return air grill ( 18 ) and acts as the return air collector.
The design of the diffuser with the angled face area sets it apart from all other concentric diffusers. The angle is an angle different than 90 degrees. In some embodiments, the angle is between about 15 degrees and 40 degrees. It has been empirically determined that 25 degree angles and 27 degree angles are especially useful. The inlet collars can be round or rectangular, depending on the customer's application of round or rectangular duct work. The supply air diffusers mounted in the face can be interchangeable. The sizes can be changed to match the amount of air flow desired by the customer. The top ( 36 ) design allows the customer the option to install a duct-mounted smoke detector ( 76 ) having a smoke pan ( 72 ) and an access door ( 96 ) as well. The sheet metal construction makes the device durable, ensuring long life and safe transportation. A smoke pan ( 72 ) is positioned on the top ( 36 ) in either the return side, supply side, or both, depending on the customers choice.
In order to make an exemplary embodiment of the device, the sides ( 14 ) are cut from, for example, 24 gauge sheet metal from a pattern using a computer numerical control (CNC) plasma cutting machine. The sides ( 14 ) can also be made using a shear and ordinary sheet metal hand type snips. The face portions can be bent to the proper angle and the side portions can have the flange area bent on a sheet metal brake. The insulation can be cut with a knife to match the sides ( 14 ). The insulation can be then glued and pinned, using welded or sticky back pins. The face ( 12 ) portion can be cut from a pattern using a CNC plasma cutting machine. The face ( 12 ) portion can also be made using a shear, ordinary sheet metal hand snips, and a hand brake. The center return air grille, and the supply air diffusers can be purchased from a manufacturer. The size of each depends on the size of the instant device that is being built to match a desired air flow quantity. The center return air duct transition can be made from a pattern using a CNC plasma cutting machine or by a shear, hand snips and brake. The center return air duct transition can use a Pittsburgh lock or snap lock to join the seams. These seams can be created by a roll forming machine with the proper rolls to provide one of the desire locks used for assembling. The sides ( 14 ), face ( 12 ), and trim ( 70 ) can be held together using pop-rivets, and sealed with duct sealing compound or caulk. The supply air diffusers can be mounted in a pre-cut hole in the face to match the size of the supply air diffuser and can be held in place by sheet metal screws. The round inlet collars can be purchased from a manufacturer of duct work fittings. The rectangular collars can be made by using a shear and sheet metal hand brake.
FIG. 4 is a perspective view of an exemplary embodiment ( 10 ) of the invention including a plurality of upper mount members or faces ( 12 ), and a plurality of lower mount members or sides ( 14 ) showing the means of connecting and fastening with four trim ( 70 ) pieces. The trim ( 70 ) also facilitates mounting the device ( 10 ) in a ceiling, providing a means of trim. FIG. 5 is a side view of an exemplary embodiment ( 10 ) of the invention shown in FIG. 4 . Device ( 10 ) can include a smoke pan ( 72 ) mounted in either the return air, supply air, or both, that includes a smoke detector ( 76 ), sampling tube ( 90 ), and access door ( 96 ) to test the air in flow for smoke. An air inlet collar ( 74 ) is provided as well as an air outlet collar ( 74 ). A plurality of baffles is provided ( 78 , 84 ) to balance supply air being delivered to the room in which device ( 10 ) is mounted. FIG. 6 is an exploded perspective view of an exemplary embodiment ( 10 ) of the invention illustrating interior components including component ( 84 ) which is a connector.
FIGS. 7A and 7B form an exploded perspective view of an exemplary embodiment the invention illustrating interior components including an air or smoke sampling tube ( 90 ). It should be noted that device ( 10 ) is an angled air exchange structure, and apparatus is bidirectional in that air flow is both supply air and return air. The instant device can be used in the air distribution of a fan forced HVAC unit. It can be directly connected with either flexible duct work or hard duct work to the supply air outlet and return air inlet of the HVAC fan unit. The instant device can be typically used in commercial and industrial applications.
In alternative embodiments, the angled face concentric diffuser can be made in multiple sizes to accommodate the desired amount of air flow quantities required.
FIG. 8 illustrates the addition of an access panel or access door ( 96 ) in an opening ( 94 ) of smoke pan ( 72 ). Accordingly a user or other person (e.g., installer or other person) can access sampling tube ( 90 ) by going through the access door ( 96 ). This is an improvement over embodiments where a plurality of access doors, ports, openings etc. must be traversed in order to access a sampling tube. For example in some embodiments not illustrated a user must also traverse an area containing return air (outgoing air) before accessing an area containing supply air (ingoing air) that is being sampled by an air sampling tube. As is shown in FIGS. 7 b and 8 , the sampling tube extends into the inner surround centrally aligned with the diameters of the collars and completely across both collars such that the sampling tube is subjected to a maximal air pressure within the inner surround. In the case of a rectangular collar (not shown but also described herein), the rectangle inherently includes a center point and the sampling tube can be centrally aligned with the center point.
It should be understood, of course, that the foregoing relates to exemplary embodiments of the invention and that modifications may be made without departing from the spirit and scope of the invention as set forth in the following claims. | Apparatus includes a four sided ceiling pass-through support structure and an angled air exchange structure wherein an air inlet portion is substantially co-planer with the ceiling and at least one air outlet portion is angled with respect to the air inlet portion at an angle other than 90 degrees. | 5 |
The present invention relates to a fluidized bed incinerator and more particularly to an incinerator for burning waste material having a rotatable hearth for initially drying and partially burning the waste materials and a fluidized bed furnace for receiving the partially burnt waste from the rotating hearth and completing the burning thereof.
BACKGROUND OF THE INVENTION
There have been provided in the past many different types of incinerators for burning waste materials resulting from municipal trash collections, business or industrial plant operations, sewage systems, and the like. The materials to be consumed are necessarily varied not only in shape and composition but also in moisture content. As a result such materials are not always completely consumed in existing incinerators causing smoke and generation of clinkers or unburnt cakes of waste material which are impossible to reburn and must be otherwise gotten rid of.
An example of a prior art incinerator is shown in U.S. Pat. No. 3,605,656 to J. B. Stribling in which waste materials are fed by a conveyor onto a rotatable hearth in a combustion chamber and burnt during displacement from a peripheral portion of the hearth toward the center, the burnt material passing out through an ash outlet in the center of the hearth. During the displacement of the waste materials on the hearth, deflectors are provided for agitating the waste materials in an effort to increase the drying of the material, maximize combustion and reduce the formation of clinkers. Nevertheless, it has been found that the burning operation is not always complete in such a incinerator due to the wide variation in the nature and character of the waste materials supplied to the furnace.
Examplary of another type of furnace is shown in U.S. Pat. No. 3,772,998 having a multi-stage dryer for first drying waste material and a fluidized bed furnace for receiving the materials from the dryer and burning it under forced air and at high temperatures. The use of the dryer more satisfactorily drys the waste material permitting more complete combustion in the fluidized bed furnace, but the equipment is expensive to manufacture, is complicated in construction and costly to operate.
SUMMARY OF THE INVENTION
An object of the present invention therefore is to provide a new and improved and more efficient incinerator having a fluidized bed furnace for burning any kind of waste material from town refuge, waste products of plants or any other types of places.
Yet another object of the present invention is to provide such an incinerator in combination with a first combustion chamber having a rotating hearth for initially drying and partially burning the waste materials before burning them in a fluidized bed furnace in order to ensure more complete combustion of the materials.
To achieve the foregoing objects and in accordance with its purpose, the fluidized bed incinerator of the present invention comprises shield wall means defining therein a first cylindrical combustion chamber, means for drying and burning waste materials in the chamber under forced air and at high temperature, an annular rotatable hearth rotatable about a vertical axis in the combustion chamber and defining the bottom thereof, means for rotating the hearth, an opening in said wall means and conveyer means for charging waste materials through said opening onto the periphery of said hearth, said hearth having a downwardly extending outlet in the center thereof, means disposed above the hearth for moving the waste materials from the periphery to the center of the hearth and for breaking up and agitating the materials to ensure contact with the hot air and high temperatures in the first combustion chamber and effect a drying and partial burning thereof, a second combustion chamber for completing the burning thereof comprising a fluidized bed furnace connected to the outlet in the hearth for receiving the dried and partially burnt material as it falls through the outlet, said furnace having a perforated plate located in the lower portion of the second combustion chamber, means for forcing air upwardly through the plate into said second combustion chamber to maintain the materials in a fluidized and burning state, and an ash outlet extending upwardly through the plate and the center of the second combustion chamber and having an upper inlet end in the chamber for receiving ash from the second combustion chamber and a lower outlet end for discharging the ash from the incinerator.
DETAILED DESCRIPTION
The accompanying drawing which is incorporated in and constitutes a part of this specification, illustrates one embodiment of the invention and together with a description serves to explain the principles of the invention.
The drawing is a vertical sectional view of an incinerator constructed in accordance with the present invention having a rotatable hearth and a fluidized bed furnace.
With reference to the drawing, there is shown an incinerator (1) having shield wall means defining a first cylindrical combustion chamber 6 and an annular rotatable hearth 2 constituting the bottom of the chamber. As embodied the shield wall means is constructed of conventional fire brick and consists of a cylindrical and vertically disposed wall portion 3 and a conical wall portion 5 leading to a smoke flue 4.
Tangential combustion air inlets 8 and fuel burners 7 are provided in wall portion 3 above hearth 2 and are operated in combination with a blower and fuel supply not shown to direct a tangential flow of air and flame into combustion chamber 6 in a conventional manner.
An opening 15 is provided in wall 3 through which a conveyer means 16 passes for feeding or charging waste materials to combustion chamber 6 and more particularly to the periphery of hearth 2. Rotatable hearth 2 has a cylindrical outlet 17 which extends downwardly from the center of the hearth and defines a second combustion chamber 25 as more fully described below. Means such as a gear 9 operated and controlled by a suitable motor (not shown) and cooperating with a gear A on a downwardly extending wall portion 24 of rotatable hearth 2 is provided for turning the hearth at a predetermined speed of rotation.
Rotatable means 14 located above the hearth 2 are further provided to move the material from the periphery toward the cylindrical outlet 17 in the center of the hearth and to agitate and break up the waste materials to ensure contact with the hot air and the high temepratures in the chamber. Rotatable means 14 as embodied comprises a spiral shaped plow 12 mounted on a shaft 13 that extends through cylindrical wall 3 and is rotated by any suitable means not shown.
The waste materials are dryed and partially burned during rotation of the hearth and then moved by spiral plow 12 toward central outlet 17 in the center of the hearth. This tends to eliminate the generation of clinkers and facilitates the drying of any kind of wet material that may be fed to the incinerator. The partially burned waste materials then fall down through central outlet 17 and into a second combustion chamber 25 defined by the downwardly extending wall portion 24 of the hearth.
A perforated plate 22 is located at the bottom of second combustion chamber 25 through which hot air is forced to form a fluidized bed furnace in chamber 25. A cylindrical skirt 18 extends downwardly from the bottom of wall portion 24 into a water bath 21 to provide a water-seal arrangement between the atmosphere and the internal chambers of the incinerator.
A further water-seal arrangement is also provided between wall portion 3 and rotatable hearth 2 which includes skirt 10A extending down into an annular channel 10 filled with water.
In accordance with the invention, means are provided for forcing air upwardly through plate 22 and into chamber 25 as shown, this means comprises a pair of pipes 20 extending upwardly through water bath 21 and into the area surrounded by skirt 18 to supply a second air flow up through second combustion chamber 25, the air eventually passing upwardly into first combustion chamber 6 and out flue 4. Suitable blowers not shown and connected to pipes 20 may be used to provide the required flow of air.
An ash outlet duct 11 is arranged in the interior of chamber 25 and passes downwardly through water-seal bath 21 having an upper inlet opening near the top of chamber 25 for receiving ash from the fluidized bed furnace and for discharging the ash into a conveyer 19 located at the bottom of the incinerator.
Stationary baffle or deflector 23 is further arranged in second combustion chamber 25 to break up any unburnt materials or to prevent them from being directly supplied into the duct 11 as they pass downwardly from hearth 2 through outlet 17 and into chamber 25 to ensure more complete combustion in the fluidized bed furnace.
As is apparent from the above description, the waste materials charged onto the periphery of the rotating hearth by conveyer 16 are turned in first chamber 6 and transferred from the peripheral portion of the hearth to the center portion while being agitated and broken up by plow 12 to facilitate their drying and to cause partial burning thereof. The dried materials on the hearth then fall immediately down into fluidized bed chamber 25 where they are fluidized by the flow of hot air from pipes 20 passing up through the holes in plates 22, the air mixing with the tangential flow of air from air inlet 8 so as to further increase the efficiency of the drying and the partial burning of the waste materials on the hearth and to eliminate the discharge of floating solid materials through flue. In chamber 25 the materials are subjected to complete combustion under the fluidized conditions created therein by the flow of air through the chamber.
In the illustrated embodiment the fluidized furnace is defined by the downwardly directed cylindrical wall portion 24 that is integral with and turns with the rotating hearth to provide for efficient transfer of the waste materials from the hearth into the fluidized chamber. However, it is to be understood that the fluidized furnace can be stationary with just the hearth turning and with a suitable connection between them without departing from the scope of the invention. In either event, ash is collected by a central duct 11 passing downwardly from the fluidized bed furnace and onto a conveyer 19. | An incinerator including a first combustion chamber having a rotatable hearth for initially drying and partially burning waste materials and a second combustion chamber comprising a fluidized bed furnace for receiving the partially burnt materials from the first chamber and completing the burning thereof. | 5 |
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to optical projection systems, and in particular to deep ultra-violet, large-field unit-magnification projection optical systems.
[0003] 2. Description of the Prior Art
[0004] Photolithography is presently employed not only in sub-micron resolution integrated circuit (IC) manufacturing, but also to an increasing degree in advanced wafer-level IC packaging as well as in semiconductor, microelectromechanical systems (MEMS), nanotechnology (i.e., forming nanoscale structures and devices), and other applications.
[0005] The present invention, as described in the Detailed Description of the Invention section below, is related to the optical system described in U.S. Pat. No. 4,391,494 (hereinafter, “the '494 patent”) issued on Jul. 5, 1983 to Ronald S. Hershel and assigned to General Signal Corporation, which patent is hereby incorporated by reference. In addition, the present invention as described below is also related to the optical system described in U.S. Pat. No. 5,031,977 (“the '977 patent”), issued on Jul. 16, 1991 to John A. Gibson and assigned to General Signal Corporation, which patent is hereby incorporated by reference.
[0006] [0006]FIG. 1 is a cross-sectional diagram of an example prior art optical system 8 according to the '494 patent. The optical system described in the '494 patent and illustrated in FIG. 1 is a unit-magnification, catadioptric, achromatic and anastigmatic, optical projection system that uses both reflective and refractive elements in a complementary fashion to achieve large field sizes and high numerical apertures (NAs). The system is basically symmetrical relative to an aperture stop located at the mirror, thus eliminating odd order aberrations such as coma, distortion and lateral color. All of the spherical surfaces are nearly concentric, with the centers of curvature located close to where the focal plane would be located were the system not folded. Thus, the resultant system is essentially independent of the index of refraction of the air in the lens, making pressure compensation unnecessary.
[0007] With continuing reference to FIG. 1, optical system 8 includes a concave spherical mirror 10 , an aperture stop 11 located at the mirror, and a composite, achromatic piano-convex doublet lens-prism assembly 12 . Mirror 10 and assembly 12 are disposed symmetrically about an optical axis 14 . Optical system 8 is essentially symmetrical relative to aperture stop 11 so that the system is initially corrected for coma, distortion, and lateral color. All of the spherical surfaces in optical system 8 are nearly concentric.
[0008] In optical system 8 , doublet-prism assembly 12 includes a meniscus lens 13 A, a piano-convex lens 13 B and symmetric fold prisms 15 A and 15 B located on opposite sides of optical axis 14 . In conjunction with mirror 10 , assembly 12 corrects the remaining optical aberrations, which include axial color, astigmatism, petzval, and spherical aberration. Symmetric fold prisms 15 A and 15 B are used to attain sufficient working space for movement of a reticle 16 and a wafer 18 . The cost of this gain in working space is the reduction of available field size to about 25% to 35% of the total potential field. In the past, this reduction in field size has not been critical since it has been possible to obtain both acceptable field size and the resolution required for the state-of-the-art circuits. However, today this field size reduction is problematic.
[0009] [0009]FIG. 2 is a cross-sectional diagram of an example prior art optical system 50 according to the '977 patent. System 50 includes a first mirror 52 and a meniscus lens 54 which is desirably of fused silica. System 50 also includes a plano-convex lens 56 , desirably of lithium fluoride, and a pair of prisms 60 - 1 , 60 - 2 made of calcium fluoride. System 50 includes an optical axis 64 . Operation of optical system 50 with a source of light exposure (desirably in the ultraviolet range) is analogous to that described in the '494 patent. System 50 has a numerical aperture (NA) of 0.350 and design wavelengths of 249.8 nanometers and 243.8 nanometers.
[0010] Unfortunately, for larger NA applications (i.e., NA≧0.435), both the '494 and the '977 systems of a reasonable size cannot achieve high quality imagery over field sizes having a field height larger than 23 mm in the DUV (Deep Ultra-violet) spctrum.
SUMMARY OF THE INVENTION
[0011] A first aspect of the invention is a projection optical system. The system includes along an optical axis a mirror having a concave surface, and an aperture stop located at the mirror that determines a numerical aperture (NA) of the system. The system also includes a lens group with positive refracting power arranged adjacent the mirror and spaced apart therefrom. The lens group comprises in order towards the mirror: a) first and second prisms arranged on opposite sides of the optical axis and each having a planar surface, wherein the planar surfaces are arranged adjacent object and image planes, respectively; and b) a first positive lens, a second negative lens, a third positive lens and a fourth negative lens, wherein the lenses of the lens group have surfaces that are non-concentric with respect to the mirror surface.
[0012] A second aspect of the invention is a photolithography system that includes the projection optical system of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] [0013]FIG. 1 is a cross-sectional diagram of an example prior art unit-magnification projection optical system according to the '494 patent;
[0014] [0014]FIG. 2 is a cross-sectional diagram of an example prior art unit-magnification projection optical system according to the '977 patent;
[0015] [0015]FIG. 3 is cross-sectional diagram of a generalized embodiment of the unit-magnification projection optical system of the present invention; and
[0016] [0016]FIG. 4 is a schematic diagram of a photolithography system employing the unit-magnification projection optical system of the present invention.
[0017] The various elements depicted in the drawings are merely representational and are not necessarily drawn to scale. Certain proportions thereof may be exaggerated, while others may be minimized. The drawings are intended to illustrate various implementations of the invention, which can be understood and appropriately carried out by those of ordinary skill in the art.
DETAILED DESCRIPTION OF THE INVENTION
[0018] The unit-magnification projection optical system of the present invention is an improvement over the prior art optical system of the '494 patent and the '977 patent, embodiments of which are described briefly above and illustrated in FIGS. 1 and 2.
[0019] The projection optical system of the present invention provides an optical design configuration that forms the basis of unit magnification projection optical system suitable for application in exposure apparatus utilizing illumination systems with excimer laser radiation sources such as a KrF laser (248 nm), an ArF laser (193 nm) and an F2 laser (157 nm). Moreover, the present invention provides a common lens design configuration with refractive optical components (prism and lens elements) manufacturable using low refractive index optical materials (such as fused silica, calcium fluoride, barium fluoride, strontium fluoride, etc.), that transmit radiation having the above-mentioned DUV laser wavelengths.
[0020] The projection optical system, of the present invention as described in detail below has very good image quality (i.e., Strehl ratios greater than 0.96).
[0021] [0021]FIG. 3 is a cross-sectional diagram of a generalized embodiment of a DUV unit-magnification projection optical system 100 according to the present invention. Projection optical system 100 includes, along an axis OA, a concave spherical mirror M. In an example embodiment, mirror M includes an aperture AP on the optical axis. Aperture AP may be used, for example, to introduce light into the optical system for performing functions other than direct imaging with optical system 100 , such as for aligning an object (e.g., a mask) with its image, or inspecting the object.
[0022] Optical system 100 further includes an aperture stop AS 1 located at mirror M. In an example embodiment, aperture stop AS 1 is variable and may include any one of the known forms for varying the size of an aperture in an optical system, such as an adjustable iris. In an example embodiment, the size of variable aperture stop AS 1 is manually set. In another example embodiment, variable aperture stop AS 1 is operatively connected via a line 101 (e.g., a wire) to a controller 102 that allows for automatically setting the size of the aperture stop. Aperture stop AS 1 defines the numerical aperture NA of the system, which in example embodiments of the present invention is in the range of between 0.3 and 0.5 (inclusive).
[0023] Optical system 100 further includes a prism/lens group G (hereinafter, simply “lens group G”) with positive refractive power arranged along axis OA adjacent to, and spaced apart from, mirror M. Lens group G includes two prisms PA and PB farthest from mirror M and located on opposite sides of optical axis OA. Prism PA has a planar surface S 1 A, and prism PB has a planar surface S 1 B. Surface S 1 A faces an object plane OP 1 and surface S 1 B faces an image plane IP 1 . The object plane OP 1 and the image plane IP 1 are spaced apart from respective planar surfaces S 1 A and S 1 B by respective gaps WDA and WDB representing working distances. In example embodiments where there is complete symmetry with respect to aperture stop AS 1 , WDA=WDB. Since WDA and WDB are equal to each other, in the accompanying Tables 1-7 those distances are referred collectively to as WD.
[0024] Prisms PA and PB play a role in the aberration correction, including chromatic aberration correction. Prisms PA and PB also serve to separate object plane OP 1 from image plane IP 1 (without prisms PA and PB, the object and image planes would be co-planar).
[0025] Lens group G further includes, in order from prisms PA and PB toward mirror M, lens elements L 1 , L 2 , L 3 , and L 4 disposed symmetrically about axis OA. The refractive powers of the lens elements are such that L 1 is positive, L 2 is negative, L 3 is positive and L 4 is negative. The optical system is also basically symmetrical relative to aperture stop AS 1 and thus initially corrected for coma, distortion, and lateral color. Moreover, the lens group G, in conjunction with the prisms PA and PB, and the mirror M, corrects the remaining optical aberrations, which include axial color, astigmatism, petzval, and spherical aberration. The chromatic variations of the optical aberrations are reduced also by the + − + − lens element geometry and by the alternating optical materials choice. Together, these two features greatly help to boost the optical performance of optical system 100 in achieving a sufficiently high quality imagery over a large field and with a high numerical aperture in a 1×, DUV exposure system. In particular, L 3 and L 4 , improve the overall correction of astigmatism and petzval curvature in optical system 100 helping to provide a flat field. Mirror M, when aspherized corrects higher order spherical aberrations, and also improves the overall residual aberration balance in system 100 .
[0026] The respective working distances WDA and WDB provide sufficient mechanical clearances and spaces for positioning a large wafer W and a large reticle R in image plane IP 1 and object plane OP 1 , respectively.
Example Designs
[0027] While the projection optical system of the present invention is described in conjunction with the optical design layout shown in FIG. 3, it will be understood that it is not intended to limit the invention to this design form, but also intended to cover alternatives, modifications and equivalents as may be included within the spirit and scope of the invention as defined and described in connection with particular design examples having the optical prescriptions shown in Tables 1-7, and as set forth in the claims. Each of the design examples in Table 1-7, has a design form based on the general design configuration illustrated in FIG. 3.
[0028] Since projection optical system 100 of the present invention is completely symmetric with respect to aperture stop AS 1 at mirror M, the optical prescriptions in accompanying Tables 1-7 include only values of the optical specifications from object plane OP 1 to the concave mirror M.
[0029] In Tables 1-7, a positive radius indicates the center of curvature is to the right of the surface, and a negative radius indicates the center of curvature is to the left. The thickness is the axial distance to the next surface. All dimensions are in millimeters. All of the example embodiments basically preserve the system symmetry relative to the aperture stop located at the concave mirror thus inherently eliminating the odd order aberrations such as coma, distortion, and lateral color. There are no lens elements with concentric surfaces in lens group G, nor are there any lens surfaces that are concentric with mirror M.
[0030] Further, “S#” stands for surface number, e.g. as labeled across the bottom of the lens system in FIG. 3, “T or S” stands for “thickness or separation”, and “STOP” stands for “aperture stop AS 1 ”. Also, “CC” stands for “concave” and “CX” stands for “convex.”
[0031] Further, under the heading “surface shape”, an aspheric surface is denoted by “ASP”, a planar (flat) surface by “FLT” and a spherical surface by “SPH”.
[0032] The aspheric equation describing an aspherical surface is given by:
Z = ( CURV ) Y 2 1 + ( 1 - ( 1 + K ) ( CURV ) 2 Y 2 ) 1 / 2 + ( A ) Y 4 + ( B ) Y 6 + ( C ) Y 8 + ( D ) Y 10
[0033] wherein “CURV” is the spherical curvature of the surface, K is the conic constant, and A, B, C, and D are the aspheric coefficients. In the Tables, “E” denotes exponential notation (powers of 10).
[0034] In the projection optical system 100 as set forth in Table 1, prisms PA and PB, and lenses L 1 -L 4 are all formed from fused silica and are spherical lenses. The NA is 0.435, the field height is 23.2 mm. The operating wavelength range is 248.39 nm (±0.1 nm), which makes the lens suitable for use with a DUV laser radiation source. When employed with a narrowed or ultra-line narrowed DUV laser source, optical system 100 yields reasonably high quality imagery.
[0035] In the projection optical system 100 as set forth in Table 2, prisms PA and PB and lenses L 1 and L 3 are formed from calcium fluoride, and lenses L 2 and L 4 are formed from fused silica. All the lenses are spherical lenses. In addition, mirror M has an aspherical surface. The NA is 0.435, the field height is 23.2 mm. The operating wavelength range is 248.34 nm (±0.5 nm), which makes the lens suitable for use with a DUV laser radiation source. The combination of calcium fluoride and fused silica materials for the lens group G, i.e. calcium fluoride for the positive lens elements and fused silica for the negative elements, corrects axial color and the chromatic variations of residual aberrations. This enables optical system 100 to operate with a broader line width DUV laser source. The aspheric mirror corrects high order spherical aberration and thus improves overall system performance.
[0036] In the projection optical system 100 as set forth in Table 3, prisms PA and PB and lenses L 1 -L 4 are all formed from fused silica. All the lenses have spherical surfaces. In addition, the mirror has an aspherical surface. The NA is 0.435, the field height is 23.2 mm. The operating wavelength range is 193.3 nm (±0.1 nm), which makes the lens suitable for use with a DUV line narrowed or ultra-line narrowed laser radiation source.
[0037] In the projection optical system 100 as set forth in Table 4, prisms PA and PB and lenses L 1 and L 3 are formed from calcium fluoride, and lenses L 2 and L 4 are formed from fused silica. All the lenses have spherical surfaces, and mirror M has a spherical surface. The NA is 0.435, and the field height is 23.2 mm. The operating wavelength range is 193.3 nm (±0.1 nm), which makes the lens suitable for use with a DUV laser radiation source. Using calcium fluoride substrate material for positive lens elements and fused silica substrate material for negative elements enhances the correction of axial chromatic aberration as well as reduces the chromatic variation of field aberrations.
[0038] In the projection optical system 100 as set forth in Table 5, prisms PA and PB and lenses L 1 and L 3 are formed from calcium fluoride, and lenses L 2 and L 4 are formed from fused silica. All the lenses have spherical surfaces, and mirror M has an aspherical surface. The NA is 0.435, the field height is 23.2 mm. The operating wavelength range is 193.3 nm (±0.1 nm), which makes the lens suitable for use with a DUV laser radiation source. As in the embodiment of Table 4, the embodiment of Table 5 has well-corrected chromatic aberrations and chromatic variations of residual field aberrations. The aspheric mirror M provides correction of higher order spherical aberrations and overall balance of residual aberrations.
[0039] In the projection optical system 100 as set forth in Table 6, prisms PA and PB and lenses L 1 -L 4 are all formed from calcium fluoride. All the lenses have spherical surfaces. In addition, the mirror has an aspherical surface. The NA is 0.435, the field height is 23.2 mm. The operating wavelength range is 157.631 nm (±0.0008 nm), which makes the lens suitable for use with a DUV line narrowed or ultra-line narrowed laser radiation source.
[0040] In the projection optical system 100 as set forth in Table 7, prisms PA and PB and lenses L 1 -L 4 are all formed from calcium fluoride. All the lenses have spherical surfaces. In addition, the mirror has an aspherical surface. The NA is 0.50, and the field height is 23.2 mm. The operating wavelength range is 157.631 nm (±0.0008 nm), which makes the lens suitable for use with a DUV line narrowed or ultra line narrowed laser radiation source. A broader DUV laser source may be used if the two optical materials are used in the embodiments shown in Tables 6 and 7, such as calcium fluoride for the positive lens elements and barium fluoride for the negative lens elements.
Photolithography System
[0041] [0041]FIG. 4 is a schematic diagram of a photolithography system 200 employing the unit-magnification projection optical system 100 of the present invention. System 200 has an optical axis A 2 and includes along the optical axis a mask stage 210 adapted to support a mask 220 at object plane OP 1 . Mask 220 has a pattern 224 formed on a mask surface 226 . An illuminator 230 is arranged adjacent mask stage 210 opposite optical system 100 and is adapted to illuminate mask (reticle) 220 .
[0042] System 200 also includes a wafer stage 240 adapted to movably support a wafer 246 at image plane IP 1 . In an example embodiment, wafer 246 is coated with a photosensitive layer 250 that is activated by one or more wavelengths of radiation from the illuminator. Such radiation is referred to in the art as “actinic radiation”. In an example embodiment, the one or more wavelengths of radiation include 248 nm, 193 nm and 157 nm.
[0043] In operation, illuminator 230 illuminates mask 220 while stage 240 positions wafer 250 to align the image with previously produced patterns so that pattern 224 is imaged at wafer 246 by optical system 100 , thereby forming a pattern in photoresist layer 250 . The result is an exposure field EF that occupies a portion of the wafer surface. Wafer stage 240 then moves (“steps”) wafer 246 in a given direction (e.g., the x-direction) by a given increment (e.g., the size of one exposure field EF), and the exposure process is repeated. This step-and-repeat exposure process is continued (hence the name “step-and-repeat” until a desired number of scanned exposure fields EF are formed on wafer 246 .
[0044] Wafer 246 is then removed from system 200 (e.g., using a wafer handling system, not shown) and processed (e.g., developed, baked, etched, etc.) to transfer the pattern formed in the photoresist in each exposure field EF to the underlying layer(s) on the wafer. Once the pattern is transferred the resist is typically stripped, a new layer of material is added with a deposition process, and the wafer is again coated with resist. Repeating the photolithography process with different masks allows for three-dimensional structures to be formed in the wafer to create operational devices, such as ICs.
[0045] In the foregoing Detailed Description, various features are grouped together in various example embodiments for ease of understanding. The many features and advantages of the present invention are apparent from the detailed specification, and, thus, it is intended by the appended claims to cover all such features and advantages of the described apparatus that follow the true spirit and scope of the invention. Furthermore, since numerous modifications and changes will readily occur to those of skill in the art, the invention is not to be limited to the exact construction and operation described herein. Accordingly, other embodiments are within the scope of the appended claims and the invention is only limited by the scope of the appended claims.
TABLE 1 NA = 0.435 Field Height (mm) = 23.2 Design Wavelengths (nm) 248.39 ± 0.1 SURFACE ELEMENT DESCRIPTION DE- S# RADIUS SHAPE T or S MATERIAL SCRIPTION 0 INF FLT 0.0000 3.5021 Working distance WD 1 INF FLT 34.0000 Fused Silica Prism A/ Prism B glass path 2 INF FLT 0.0000 3 INF FLT 43.9936 Fused Silica L1 4 −140.088 CX SPH 4.6554 5 −115.435 CC SPH 77.8000 Fused Silica L2 6 −158.457 CX SPH 1.5000 7 −2198.913 CC SPH 38.0000 Fused Silica L3 8 −411.153 CX SPH 2.7870 9 −1423.533 CC SPH 38.0000 Fused Silica L4 10 3458.549 CC SPH 305.7620 11 −543.979 CC SPH −305.7620 REFL (STOP) Mirror M
[0046] [0046] TABLE 2 NA = 0.435 Field Height (mm) = 23.2 Design Wavelengths (nm) = 248.34 ± 0.5 SURFACE DESCRIPTION ELEMENT S# RADIUS SHAPE T or S MATERIAL DESCRIPTION 0 INF FLT 0.0000 5.4824 Working distance WD 1 INF FLT 34.0000 Calcium Fluoride Prism A/Prism B glass path 2 INF FLT 0.0000 3 INF FLT 28.3056 Calcium Fluoride L1 4 −114.898 CX SPH 4.4701 5 −101.751 CC SPH 77.8000 Fused Silica L2 6 −145.446 CX SPH 1.6688 7 −647.352 CC SPH 38.0000 Calcium Fluoride L3 8 −447.517 CX SPH 1.5000 9 −1817.472 CC SPH 38.0000 Fused Silica L4 10 −5113.783 CX SPH 310.7731 11 −531.928 CC ASP −310.7731 REFL (STOP) Mirror M ASPHERIC S# CURV K A B C D S11 −0.00187995 0.000000 5.90655E−12 8.61447E−17 5.86675E−22 8.42714E−27
[0047] [0047] TABLE 3 NA = 0.435 Field Height (mm) = 23.2 Design Wavelengths (nm) = 93.3 ± 0.1 SURFACE DESCRIPTION ELEMENT S# RADIUS SHAPE T or S MATERIAL DESCRIPTION 0 INF FLT 0.0000 4.0000 Working distance WD 1 INF FLT 34.0000 Fused Silica Prism A/Prism B glass path 2 INF FLT 0.0000 3 INF FLT 43.9936 Fused Silica L1 4 −137.305 CX SPH 4.3078 5 −116.108 CC SPH 77.8000 Fused Silica L2 6 −161.314 CX SPH 1.5000 7 −481.652 CC SPH 38.0000 Fused Silica L3 8 −395.742 CX SPH 1.5002 9 −1012.080 CC SPH 38.0000 Fused Silica L4 10 −1266.111 CX SPH 306.8983 11 −544.016 CC ASP −306.8983 REFL (STOP) Mirror M ASPHERIC S# CURV K A B C D S11 −0.00183818 0.000000 2.58962E−11 1.98197E−16 8.56012E−22 1.50805E−26
[0048] [0048] TABLE 4 NA = 0.435 Field Height (mm) = 23.2 Design Wavelengths (nm) = 193.3 ± 0.1 SURFACE DESCRIPTION ELEMENT S# RADIUS SHAPE T or S MATERIAL DESCRIPTION 0 INF FLT 0.0000 3.5000 Working distance WD 1 INF FLT 34.0000 Calcium Fluoride Prism A/Prism B glass path 2 INF FLT 0.0000 3 INF FLT 43.9936 Calcium Fluoride L1 4 −137.984 CX SPH 5.7288 5 −116.193 CC SPH 77.8000 Fused Silica L2 6 −158.614 CX SPH 13.8279 7 −1852.115 CC SPH 38.0000 Calcium Fluoride L3 8 −515.570 CX SPH 1.5000 9 −3516.377 CC SPH 38.0000 Fused Silica L4 10 3090.388 CC SPH 293.6497 11 −543.130 CC SPH −293.6497 REFL (STOP) Mirror M
[0049] [0049] TABLE 5 NA = 0.435 Field Height (mm) = 23.2 Design Wavelengths (nm) = 193.3 ± 0.1 SURFACE DESCRIPTION ELEMENT S# RADIUS SHAPE T or S MATERIAL DESCRIPTION 0 INF FLT 0.0000 3.5000 Working distance WD 1 INF FLT 34.0000 Calcium Fluoride Prism A/Prism B glass path 2 INF FLT 0.0000 3 INF FLT 43.9936 Calcium Fluoride L1 4 −138.821 CX SPH 6.2692 5 −116.466 CC SPH 77.8000 Fused Silica L2 6 −158.824 CX SPH 2.0521 7 −1391.235 CC SPH 38.0000 Calcium Fluoride L3 8 −457.136 CX SPH 1.5000 9 −2126.796 CC SPH 38.0000 Fused Silica L4 10 5607.105 CC SPH 304.8851 11 −543.641 CC ASP −304.8851 REFL (STOP) Mirror M ASPHERIC S# CURV K A B C D S11 −0.00183945 0.000000 1.14297E−12 1.51380E−17 1.57864E−23 5.81245E−27
[0050] [0050] TABLE 6 NA = 0.435 Field Height (mm) = 23.2 Design Wavelengths (nm) = 157.631 ± 0.0008 SURFACE DESCRIPTION ELEMENT S# RADIUS SHAPE T or S MATERIAL DESCRIPTION 0 INF FLT 0.0000 4.0000 Working distance WD 1 INF FLT 34.0000 Calcium Fluoride Prism A/Prism B glass path 2 INF FLT 0.0000 3 INF FLT 47.5563 Calcium Fluoride L1 4 −140.686 CX SPH 4.4547 5 −117.667 CC SPH 77.8000 Calcium Fluoride L2 6 −162.562 CX SPH 1.5000 7 −528.689 CC SPH 38.0000 Calcium Fluoride L3 8 −401.134 CX SPH 1.5000 9 −1563.422 CC SPH 38.0000 Calcium Fluoride L4 10 −2463.529 CX SPH 303.1890 11 −544.406 CC ASP −303.1890 REFL (STOP) Mirror M ASPHERIC S# CURV K A B C D S11 −0.00183686 0.000000 1.96149E−11 1.55956E−16 8.12495E−22 1.21311E−26
[0051] [0051] TABLE 7 NA = 0.50 Field Height (mm) = 23.2 Design Wavelengths (nm) = 157.631 ± 0.0008 SURFACE DESCRIPTION ELEMENT S# RADIUS SHAPE T or S MATERIAL DESCRIPTION 0 INF FLT 0.0000 4.0000 Working distance WD 1 INF FLT 34.0000 Calcium Fluoride Prism A/Prism B glass path 2 INF FLT 0.0000 3 INF FLT 47.5563 Calcium Fluoride L1 4 −146.835 CX SPH 4.9586 5 −120.689 CC SPH 77.8000 Calcium Fluoride L2 6 −163.592 CX SPH 1.5000 7 −546.710 CC SPH 38.0000 Calcium Fluoride L3 8 −403.614 CX SPH 1.5000 9 −2316.156 CC SPH 38.0000 Calcium Fluoride LE 10 −3758.411 CX SPH 302.6851 11 −545.373 CC ASP −302.6851 REFL (STOP) Mirror M ASPHERIC S# CURV K A B C D S11 −0.00183361 0.000000 2.61844E−11 1.93771E−16 8.38751E−22 1.46130E−26 | A 1× projection optical system for deep ultra-violet (DUV) photolithography is disclosed. The optical system is a modified Dyson system capable of imaging a relatively large field at high numerical apertures at DUV wavelengths. The optical system includes a lens group having first and second prisms and four lenses having a positive-negative-positive negative arrangement as arranged in order from the prisms toward the mirror. A projection photolithography system that employs the projection optical system of the invention is also disclosed. | 6 |
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation in part of U.S. application Ser. No. 09/860,025, filed on May 16, 2001, incorporated herein by reference in its entirety.
FIELD OF THE INVENTION
[0002] The present invention is related to methods of alkaline bleaching of pulps with magnesium oxide and hydrogen peroxide.
BACKGROUND OF THE INVENTION
[0003] Mechanical pulping is a process of mechanically triturating wood into fibers for the purpose of making pulp. Mechanical pulping is attractive as a method for pulping because it achieves higher yields as compared with chemical pulping since lignin is retained to a large degree in mechanically pulped woods. Pulps made using any of the conventional mechanical pulping methods are mainly used for newsprint and printing papers but are typically unsuitable for high quality or durable paper products. This is due, in part, to the fact that high yield mechanical pulps are generally more difficult to bleach than chemical pulps because of the high lignin content.
[0004] There are many types of mechanical pulping, including stone grinding (SG), pressurized stone grinding (PSG), refiner mechanical pulping (RMP), thermomechanical pulping (TMP), and chemi-thermomechanical pulping (CTMP). The latter three can further be grouped generally under refiner pulping processes. In RMP, wood chips are ground between rotating metal disks. The process usually is carried out in two stages. The first stage is mainly used to separate the fibers, while the second stage is used to treat the fiber surface for improved fiber bonding of paper products. In RMP, the wood chips are refined at atmospheric pressure in both a first and a second stage refiner. The refiner processes generate heat by the friction of the metal disks rubbing against the wood. The heat is liberated as steam, which is often used to soften the incoming chips.
[0005] TMP differs from RMP in that the pulp is processed in a pressurized refiner. In the TMP process, two stages are normally used also. The first stage refiner operates at an elevated temperature and pressure, and the second stage refiner is typically at or near atmospheric pressure. Pulps made by a TMP process have high strength, which makes the TMP process the most favored mechanical pulping process. However, there is still room for improving the TMP process. The TMP process consumes large amounts of energy, and the pulp produced by the TMP process tends to be darker than most other pulps. Alkaline bleaching of mechanical pulps produced by the TMP process has been carried out using oxidative reagents, such as hydrogen peroxide. Sodium hydroxide is a strong alkali that provides the requisite high pH necessary to produce the active perhydroxyl ion, HOO − , thought to be the agent primarily responsible for bleaching.
[0006] U.S. Pat. No. 4,270,976 to Sandstrom et al., is representative of a TMP process used to produce peroxide bleached, mechanical pulp by introducing a peroxide containing bleaching solution into the grinding space of a refiner. The conventional alkalinity in the Sandstrom patent is supplied by caustic (sodium hydroxide). Sodium hydroxide requires the use of sodium silicate, which 1) acts as a pH buffer for the sodium hydroxide and 2) helps in stabilizing the peroxide. The peroxide bleaching causes oxalate formation. The highly dissolved alkali concentration with sodium hydroxide and sodium silicate promotes oxalate scale deposits on the refiner plates, interfering with the operation and efficiency of the refiner. Oxalate scale can even be present in the finished paper products. Refiner bleaching using sodium hydroxide and sodium silicate causes refiner plate filling, erratic refiner load, and “slick” pulp resulting in inadequate refining of the wood. The use of sodium silicate also requires separate facilities to store the chemical and pumps to meter the correct dosage. Darkening of the pulp can be attributed to the addition of excess quantities of sodium hydroxide. The aforementioned problems illustrate that refiner bleaching with sodium hydroxide and sodium silicate has many drawbacks that make commercial use difficult and expensive.
[0007] Accordingly, there is a need to find alternative methods of refiner bleaching that cures many of the aforementioned problems with using sodium hydroxide and sodium silicate.
[0008] The prior U.S. application Ser. No. 09/860,025, filed May 16, 2001, incorporated herein by reference in its entirety, and assigned to the assignee of the present application, describes using substitute alkaline chemicals for sodium hydroxide. The present application further adds to the methods of the '025 application.
SUMMARY OF THE INVENTION
[0009] The present invention is related to methods of bleaching pulp under alkaline conditions with hydrogen peroxide. The methods include introducing a source of magnesium ions and hydroxyl ions, and a source of perhydroxyl ions, to a refiner. The wood particulates are refined into a pulp in the presence of the magnesium ions, hydroxyl ions, and perhydroxyl ions, to simultaneously refine and bleach the pulp in a refiner. The source of perhydroxyl ions can be added concurrently with the source of magnesium ions and hydroxyl ions, or the source of perhydroxyl ions can be added to a vessel containing the refined pulp after refining takes place. The refiner to which sources of magnesium ions, hydroxyl ions, and perhydroxyl ions are added can be any refiner in a mechanical pulp mill. Any one or all of the refiners in a mill can be supplied with the source of magnesium ions and hydroxyl ions and the source of perhydroxyl ions. For example, the refiner can be either one or both of the primary pressurized refiner and the secondary atmospheric refiner in a two-stage refining process used for thermal mechanical pulp production. The present invention is not, however, limited to a two-stage process, but can be applied to any high consistency refining process. A source of magnesium and hydroxyl ions is magnesium oxide and water. A source of perhydroxyl ions is hydrogen peroxide.
[0010] It is well documented that increasing alkalinity can have a positive influence on the tensile strength of pulp. The alkalinity is traditionally achieved using sodium hydroxide. Most mills can not add the sodium hydroxide to the refiner due to the detrimental effects that can occur, such as plate filling and erratic refiner operation. Magnesium hydroxide appears to give the same tensile strength improvement as sodium hydroxide and has other related advantages. Addition of magnesium hydroxide directly at or before the refiner does not exhibit the same problems observed with sodium hydroxide.
[0011] Peroxide bleaching with sodium hydroxide/sodium silicate chemicals generates calcium oxalate scale when the oxalate ion combines with calcium in the process water or from the wood. The scale forms tenacious deposits on the equipment. The scale can end up in the finished paper product and cause problems with the paper press. Magnesium ions, on the other hand, react with oxalate ions to form magnesium oxalate that is more soluble than calcium oxalate, thus reducing scale. The result is the reduction or elimination of scale control chemicals or other expensive preventative measures.
[0012] Magnesium oxide/hydroxide and hydrogen peroxide bleaching has the advantage of eliminating the use of sodium silicate. The high anionic charge associated with sodium silicate interferes with downstream paper machine retention aid chemistry. Silicates along with other process materials contribute to the conductivity and negative charge of the water. The elimination of sodium silicate should result in improved paper machine retentions, and allow for retention aid optimization.
[0013] Using a magnesium oxide and water slurry as the substitute for sodium hydroxide and sodium silicate in a refiner lowers bleaching times and reduces cost. Magnesium oxide and magnesium hydroxide are safe and nonhazardous and will not cause chemical burns. Magnesium hydroxide is classified as a weak base, so it buffers the bleaching reaction to a lower pH, minimizing the darkening reaction seen with sodium hydroxide. Other benefits of using a magnesium oxide and water slurry in a refiner include a reduction in the refining energy. Refiner bleaching with magnesium oxide/water slurry and hydrogen peroxide can be practiced in each stage of refining or in all refining stages. The present invention encompasses high, medium, and low consistency refining. The present invention can be applied to any refiner bleaching process. The methods described herein can be used for high consistency mechanical pulps, as well as recycled pulps from post consumer sources, and chemical pulps, such as Kraft and sulfite pulps that are processed through a refiner. The latter recycled pulps and chemical pulps are typically low to medium consistency processes. The raw material to be refined can include hardwoods and softwoods. The methods described herein can be used in processes of making thermal mechanical pulp, refiner mechanical pulp, and ground wood pulp.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The foregoing aspects and many of the attendant advantages of this invention will become more readily appreciated as the same become better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein:
[0015] [0015]FIG. 1 is a schematic illustration showing one embodiment of a method according to the present invention; and
[0016] [0016]FIG. 2 is a graphical representation of the brightness versus hydrogen peroxide usage comparing a process using magnesium hydroxide at the refiner with a process using sodium hydroxide and sodium silicate chemicals.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0017] Referring now to FIG. 1, a representative method according to the present invention is schematically illustrated. A two-stage refining system with associated unit operations, including a bleaching tower between the primary and the secondary refiner, is represented.
[0018] Block 100 represents a suitable supply of wood particulates, such as wood chips coming from chip storage silos. Wood chips suitable for use in the present invention can be derived from softwood tree species such as, but not limited to: fir (such as Douglas fir and balsam fir), pine (such as Eastern white pine and Loblolly pine), spruce (such as white spruce), larch (such as Eastern larch), cedar, and hemlock (such as Eastern and Western hemlock). Examples of hardwood tree species include, but are not limited to: acacia, alder (such as red alder and European black alder), aspen (such as quaking aspen), beech, birch, oak (such as white oak), gum trees (such as eucalyptus and sweet gum), poplar (such as balsam poplar, Eastern cottonwood, black cottonwood, and yellow poplar), gmelina, maple (such as sugar maple, red maple, silver maple, and big leaf maple). Hemlock and pine tree species are preferred for their availability and cost.
[0019] The wood chips coming from storage silos are washed in a washing apparatus represented by block 102 . Washing removes any grit or debris present in the chips that can damage the refiner and cause premature wear of the plates. The chip washer receives hot water from steam producers and steam users within the mill, and thus can operate at a temperature of about 100° F. to about 150° F.
[0020] After the chip washer, a digester or “preheater,” represented by block 104 , is provided. Digesters expose the wood chips to steam to soften the lignin in the wood. Operating conditions in the digester are dependent on the wood chip species, and size. On hemlock wood chips of typical size, for example, the digester can operate at a pressure of about 38 psig and a retention time period of about 2 to about 4 minutes. Digesters or “preheaters” are common in mechanical refining mills. In one embodiment, the digester uses steam recovered from a downstream cyclone separator and/or steam from a make up line to heat the wood chips prior to feeding into a primary refiner. Softening the lignin in the chips conserves energy in the refining stages.
[0021] A plug wiper pump, represented by block 132 , adds water to the softened wood chips via a plug wiper, block 105 , prior to refining, to control the consistency at about 50%. “Consistency” as used herein refers to the ratio of solids to liquids expressed as a percentage.
[0022] A primary refiner, designated as block 106 , is provided after the digester. The primary refiner is a pressurized refiner that can operate in the range of from slightly above atmospheric pressure to several tens of pounds per square inch of pressure. Typical operating pressure is about 10 psig to about 40 psig, but may be higher or lower. Secondary and/or any other additional refiners can operate at near atmospheric or above atmospheric pressures. In one embodiment, the primary refiner can operate at a pressure of about 38 psig. One or more refiners are common in mechanical pulp refining mills.
[0023] A refiner is an apparatus that mechanically separates the wood into its constituent fibers resulting in liberation of the single fiber cellulosic pulp. There are two principal types of refiners: disc refiners and conical refiners. Either is suitable to be used in the present invention. Refining adds a substantial amount. of heat to the wood chips from the friction generated by the rotating plates. The heat is liberated in the form of steam in a downstream separator. The steam is collected from the separator and can be used in steam users, such as the digester, for energy conservation purposes. In addition, the condensate from the digester can be used in the chip washer.
[0024] According to the invention, a source of magnesium ions and hydroxyl ions is provided to a refiner. A source of perhydroxyl ions is provided to the refiner, as well. It has been discovered that refiners are especially suited for hydrogen peroxide and magnesium oxide/water slurry bleaching. Magnesium oxide is not readily soluble in water. The magnesium oxide is naturally buffered to maintain a comparatively lower pH than sodium hydroxide. Thus, alkali darkening of pulps is less frequent with magnesium oxide than with sodium hydroxide. The high temperatures and mechanical action in the refiner liberate the hydroxyl ions from the magnesium hydroxide, as necessary, to form the perhydroxyl ions, the agent primarily responsible for the bleaching reaction. The high shear, turbulent mixing and high temperatures provided by the refiner liberate the hydroxyl ions from the nearly insoluble magnesium hydroxide and/or magnesium oxide. Refiners also behave as mixers. High concentrations of hydrogen peroxide can be added allowing bleaching at high consistency. Bleaching at high consistency improves the overall brightness efficiency. Divalent magnesium ions complex and react differently with inorganic compounds as compared to monovalent sodium ions, including inhibiting scale formation.
[0025] The load on the refiner is generally expressed in terms of work performed on the pulp. Loads can be reduced with the use of magnesium hydroxide because magnesium hydroxide can be added at or before the refiner, which cannot be done with sodium hydroxide. The alkalinity causes swelling of the fibers that facilitates their separation thus, reducing load. A typical load on the refiner when using hydrogen peroxide and magnesium oxide bleaching is about 500 to about 2000 kilowatt-hours per ton of pulp.
[0026] The refined wood chips leaving the primary refiner, now called pulp, have a Canadian Standard Freeness value of about 400 to about 600 and a consistency ranging from about 15% to about 50%. The primary refiner can operate at a high consistency, which is typically understood to be about 20% or greater. However, the methods according to the present invention can be practiced in medium and low consistency processes. Medium consistency is typically about 10% to about 20% and low consistency is less than 10% and as low as about 3%. It is believed that the use of magnesium oxide and hydrogen peroxide in low and medium consistency processes would be less efficient in terms of chemical usage as compared with the high consistency processes. Nevertheless, use of the present invention in any medium and low consistency process would still provide some advantages over using sodium hydroxide.
[0027] The pressure is reduced after the primary refiner, which results in separation of the heat and water from the pulp via steam production. The separation operation, generally represented by block 108 , can operate as one or a series of pressurized and/or atmospheric pressure vessels.
[0028] In one embodiment, the separator is a cyclone separator operated at normal atmospheric pressure or at a pressure slightly higher than atmospheric pressure. The steam generated by the drop in pressure from the primary refiner to the separator can be used in the digester, block 104 . Condensed steam or condensate from the digester can be routed to the chip washer, block 102 .
[0029] The pulp is next conveyed from the separator through a screw conveyor, represented by block 110 , into a peroxide bleaching tower, represented by block 112 . The pH of the contents in the peroxide bleaching tower is above 7 to about 9. The pulp continues to undergo the bleaching reaction with the magnesium ions, hydroxyl ions, and perhydroxyl ions in the peroxide tower for an additional retention period of about 45 minutes to about 120 minutes, depending on the desired final pulp brightness. The pulp can be diluted at the bottom of the tower for the purpose of facilitating pumping the pulp out of the tower. The pulp leaving the peroxide tower ends up having a consistency of about 4% to about 6%. The dilution of the pulp to this low consistency will slow the bleaching reaction to essentially zero. In other embodiments of the invention, it is possible to provide the bleaching tower after the secondary refiner, or if there are more than two refiners, the bleaching tower can be provided after the last refiner. In these alternate embodiments, the source of magnesium and hydroxyl ions and the source of perhydroxyl ions can be added to the towers.
[0030] The pulp next enters a dewatering operation, represented by block 114 . A screw press is a suitable apparatus to dewater the pulp at this stage. The screw press elevates the consistency of the pulp back to about 25% to about 35%.
[0031] From the screw press, the pulp enters a secondary refiner, represented by block 116 . In one embodiment, the secondary refiner can be operated at atmospheric pressure. Alternatively, the secondary refiner can be operated at a pressure greater than atmospheric pressure. The load on the secondary refiner is about 500 to about 2000 kilowatt-hours per ton. The pulp leaves the secondary refiner having a Canadian Standard Freeness value of about 80 to about 200. The consistency of the pulp leaving the secondary refiner is about 15% to about 50%.
[0032] The pulp leaving the secondary refiner can enter a dilution chest, represented by block 118 , wherein the consistency of the pulp is reduced to about 4% to about 6%, before the pulp is cleaned up.
[0033] From the dilution chest, the pulp can be screened in one or a plurality of screening devices to remove any oversized fibers which can then be routed for further refining into any one of the refiners, preferably the secondary refiner. The screening operation can reduce the consistency of the pulp to as low as about 2%.
[0034] After the screening process, the pulp enters a “decker” operation. A decker is an apparatus that further separates water from the screened pulp to provide the desired consistency. The typical pulp consistency leaving the decker is about 6% to about 12%. The pulp produced according to the invention leaving the decker can have a Canadian Standard Freeness value of about 60 to about 200 and an ISO brightness of about 50 to about 75 or greater. The brightness achieved by hydrogen peroxide bleaching using magnesium oxide/hydroxide/water is comparable to using sodium hydroxide/sodium silicate without the drawbacks of sodium hydroxide/sodium silicate and with no impact on bleaching efficiency. It is possible to provide the source of magnesium ions and hydroxyl ions and the source of perhydroxyl ions to the decker.
[0035] The pulp product leaving the decker can be stored in any storage vessel, represented by block 124 . The pulp can be somewhat diluted in the high-density storage tanks to a consistency of about 4% to about 6% before being sent to the paper machines, represented by block 126 .
[0036] It has been discovered that peroxide bleaching with magnesium hydroxide has advantages over the conventional peroxide bleaching with sodium hydroxide/sodium silicate. Magnesium oxide typically comes as a powder. Magnesium oxide powder is only slightly soluble in water. For use in the methods according to the present invention, the magnesium oxide powder can be mixed with water to provide a slurry. Magnesium oxide (MgO) when mixed with water results in magnesium hydroxide (Mg(OH) 2 ), which in turn supplies the magnesium ions and the hydroxyl ions, needed for the generation of the perhydroxyl ions from hydrogen peroxide (H 2 O 2 ). Magnesium oxide/hydroxide/water slurry, block 130 , can be provided to any one or more refiners, either with the wood chips or in the pulp leading to the refiner, or at the refiner, such as at the eye of the refiner. Magnesium oxide/hydroxide/water slurry, block 130 , can be provided to mixers, plug wipers, bleaching towers, and deckers, for example. Hydrogen peroxide addition, block 132 , can occur at the same injection locations as magnesium oxide/hydroxide/water slurry injection. Magnesium oxide/hydroxide/water slurry injection can occur separately or concurrently with hydrogen peroxide injection. If magnesium oxide/hydroxide/water slurry injection is carried out separately in the primary refiner, the hydrogen peroxide can be injected before or after the refiner, or at the bleaching tower. Alternatively, hydrogen peroxide injection can take place with the magnesium slurry injection before or at the refiner. This manner of magnesium oxide/hydroxide/water slurry and hydrogen peroxide injection can take place in any other refiner or ancillary vessel, either separately or concurrently. The amount of magnesium oxide that is used in any one refiner or vessel is about 0.75% to about 2% based on the oven dried weight of the wood, and undiluted 100% magnesium oxide. The addition of hydrogen peroxide that is used in any one refiner or vessel is about 1% to about 12% based on the oven dried weight of wood, and undiluted 100% hydrogen peroxide.
[0037] Chelating agents or chelants, block 128 , may be added to the pulp prior to refining in the primary refiner, such as at the plug wiper. The amount of chelant added can be about 0.1% to about 0.5% based on the oven dried weight of wood and undiluted 100% chelant. Suitable chelating agents include, but are not limited to, amino polycarboxylic acids (APCA), ethylenediamenetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), nitrilotriacetic acid (NTA), phosphonic acids, ethylenediaminetetramethylene-phosphonic acid (EDTMP), diethylenetriaminepentamethylenephosphonic acid (DTPMP), nitrilotrimethylenephosphonic acid (NTMP), polycarboxylic acids, gluconates, citrates, polyacrylates, and polyaspartates, or any combination thereof. Chelating agents are useful to bind metals to prevent the decomposition of hydrogen peroxide. In addition to chelating agents, the pulp can also be provided with bleaching aids.
EXAMPLE
[0038] Experimental work was carried out to demonstrate the benefits of hydrogen peroxide bleaching with magnesium hydroxide as compared with sodium hydroxide/sodium silicate in a series of bleaching tests where a temporary equipment setup was used to supply chemicals to a commercial refiner. In this example, a pressurized mechanical double disk refiner was used, however, other pressurized and atmospheric high consistency refiners will give similar results. The chemical application process and testing is described below. The results using magnesium hydroxide were compared to historical production data that used sodium hydroxide/sodium silicate from the same refiner and test equipment.
[0039] Wood chips were processed at the rate of 7 tons/hr through the chip washer and digester shown in FIG. 1. The chips were fed to the feeder where chelants like DTPA were added at the rate of 3 lbs/ton. Plug wiper water was added to control consistency. Before the addition of the plug wiper water, a 60% slurry solution of magnesium hydroxide was mixed with the plug wiper water. The amount of slurry varied depending on the brightness target and the amount of hydrogen peroxide added. For a brightness target of 60 points, the amount of magnesium hydroxide might be 25 lbs/ton (of wood) on a dry weight basis. The amount of hydrogen peroxide might be 50 lbs/ton or 2.5% of wood. Chemical charge will vary due to normal process variation like raw chip brightness.
[0040] A 40% hydrogen peroxide solution was pumped with a variable speed gear pump to the chip feeder. A flow meter was installed ahead of the refiner to control the bleaching chemical added to the wood chips. Hydrogen peroxide was added to the refiner through one of the plug wiper nozzles. The location of the chemical injection nozzle was near the eye of the refiner. The hydrogen peroxide can also be added to the plug wiper water either before or after the magnesium hydroxide slurry has been added. The amount of hydrogen peroxide was varied and the bleached pulp was sampled from the blowline directly downstream of the refiner. The bleached samples were placed in sample bags and held in a hot water bath for 1 hour at 180° F. The sample was then tested in equipment known under the designation “Pulp Expert” from Metso Inc. The same bleaching times and test equipment were used with magnesium hydroxide as with sodium hydroxide/sodium silicate to enable comparison of the two processes. Currently, sodium hydroxide/sodium silicate and hydrogen peroxide are added after the refiner (post-refiner) and the pulp is held in a bleach tower for 1 hour.
[0041] The brightness results of the refiner bleached pulps with magnesium hydroxide and the post-refiner bleached pulps with sodium hydroxide and silicate are shown in FIG. 2. The addition of hydrogen peroxide to the eye of the primary refiner improved bleaching efficiency by over 25% to 50% on the low brightness grades (52-60) and over 60% efficiency on the high brightness grades (65+). Visual observation from the refiner confirmed that the bleached pulp was extremely homogenous in comparison to the bleach application at the top of the tower. Adding hydrogen peroxide to the refiner prevented alkali darkening which also improved bleach efficiency. Using multiple stages of refiner bleaching with magnesium hydroxide will allow much higher brightness levels to be achieved.
[0042] While the preferred embodiment of the invention has been illustrated and described, it will be appreciated that various changes can be made therein without departing from the spirit and scope of the invention. | Methods of bleaching mechanical pulp under alkaline conditions with hydrogen peroxide. The methods include introducing a source of magnesium ions and hydroxyl ions to a refiner. The wood particulates are refined into a pulp in the presence of the magnesium ions and hydroxyl ions, and optionally perhydroxyl ions to simultaneously refine and bleach the pulp in a refiner. | 3 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a search engine, and, more particularly, to a search engine which maps crawled documents into tiers and then searches those tiers in a hierarchical manner.
2. Description of the Related Art
The World Wide Web (“WWW”) is a distributed database including literally billions of pages accessible through the Internet. Searching and indexing these pages to produce useful results in response to user queries is constantly a challenge. The device typically used to search the WWW is a search engine. Maintaining a working search engine is difficult because the WWW is constantly evolving, with millions of pages being added daily and existing pages continually changing. Additionally, the cost of search execution typically corresponds directly to the size of the index searched. To deal with the massive size and amount of data in the WWW, most search engines are distributed and use replication and partitioning techniques (all discussed below) to scale down the number of documents.
A typical prior art search engine 50 is shown in FIG. 1 . Pages from the internet or other source 100 are accessed through the use of a crawler 102 . Crawler 102 aggregates documents from source 100 to ensure that these documents are searchable. Many algorithms exists for crawlers and in most cases these crawlers follow links in known hypertext documents to obtain other documents. The pages retrieved by crawler 102 are stored in a database 108 . Thereafter, these documents are indexed by an indexer 104 . Indexer 104 builds a searchable index of the documents in database 108 . Typical prior art methods for indexing include inverted files, vector spaces, suffix structures, and hybrids thereof. For example, each web page may be broken down into words and respective locations of each word on the page. The pages are then indexed by the words and their respective locations. A primary index of the whole database 108 is then broken down into a plurality of sub-indices (discussed below) and each sub-index is sent to a search node in a search node cluster 106 .
In use, a user 112 enters a search query to a dispatcher 110 . Dispatcher 110 complies a list of search nodes in cluster 106 to execute the query and forwards the query to those selected search nodes. The compiled list ensures that each partition is searched once. The search nodes in search node cluster 106 search respective parts of the primary index produced by indexer 104 and return sorted search results along with a document identifier and a score to dispatcher 110 . Dispatcher 110 merges the received results to produce a final list displayed to the users 112 sorted by relevance scores. The relevance score is a function of the query itself and the type of document produced. Factors that are used for relevance include: a static relevance score for the document such as link cardinality and page quality, superior parts of the document such as titles, metadata and document headers, authority of the document such as external references and the “level” of the references, and document statistics such as query term frequency in the document, global term frequency, and term distances within the document.
Referring now to FIG. 2 , a cluster 106 of search nodes is shown. For illustrative purposes, cluster 106 is shown in a matrix grouped in columns 122 a , 122 b , etc. and rows 124 a , 124 b , etc. In each column 122 of search nodes, the same set of indices is replicated for each respective search node. For example, the search node in column 122 a , row 124 a , includes the same subset of indices as the search node in column 122 a , 124 b . In each row 124 of search nodes, a different subset of indices is used. The indices are equally split so as to divide the amount of time for a search.
For example, the search node in column 122 a , row 124 a includes a different subset of indices than the search node in column 122 b , row 124 a . In each search node, “I” represents the index for the entire database 108 , “S” corresponds to a search node, “S n (I n )” indicates that search node n holds sub-index n of the entire index I, and “S n m (I n )” indicates that replication number m of search node n holds sub-index n of the entire index I.
Each query from dispatch 110 is sent to respective search nodes so that a single node in every partition is queried. For example, all the nodes in a row 122 a , 122 b , etc. are queried as the combination of these nodes represents that total index. That is, each row in cluster 120 is a set of search nodes comprising all the partitions of an entire index. The results are merged by dispatcher 110 and a complete result from the cluster is generated. By partitioning data in this way, the data volume is scaled. For example, if there are n columns, then the search time for each node is reduced basically by a factor of n—excluding the time used for merging results by dispatcher 110 .
By replicating the search nodes, the query processing rate for each index is increased. In FIG. 2 , all search nodes in each column hold the same index. This allows dispatcher 110 to rotate among the nodes in a column for each index partition when selecting a set of search nodes to handle an incoming query.
However, the inventors have determined that there is a highly skewed distribution of unique search queries in a typical search engine. For example, the top 25 queries may account for more than 1% of the total query volume. As a consequence, equally dividing a primary index into smaller sub-indices may not provide optimum results.
Therefore, there is a need in the art for a search engine that organizes its documents and indices in light of the distribution of search queries.
SUMMARY OF THE INVENTION
A search engine comprising a crawler which crawls the WWW and stores pages found on the WWW in a database. An indexer indexes the pages in the database to produce a primary index. A document mapping section maps pages in the database into a plurality of tiers based on a ranking of the pages. The ranking may be based on portions of the pages which have a relatively higher value context. A processor produces a plurality of sub-indices from the primary index based on the mapping. The sub-indices are stored in a search node cluster. The cluster is a matrix of search nodes logically arranged in a plurality of rows and columns. Search nodes in the same column include the same sub-index. Search nodes in the same row include distinct sub-indices. A search query received by a user is sent to a dispatcher which, in turn, forwards the query to the first tier of search nodes. A fall through algorithm is disclosed which indicates when the dispatcher should forward the search query to other tiers of search nodes.
One aspect of the invention is a method for indexing data items in a database. The method comprises retrieving data items from a database and producing a primary index of the data items. The method further comprises mapping the data items on to at least a first tier and a second tier based on respective rankings of the data items. The method further comprises producing at least a first and a second sub-index from the primary index based on the mapping; and storing the at least a first and second sub-index in different search nodes.
Another aspect of the invention is a method for searching a database. The method comprises retrieving data items from a database and producing a primary index of the data items. The method further comprises mapping data items on to at least a first tier and a second tier based on respective rankings of the data items. The method still further comprises producing at least a first and a second sub-index from the primary index based on the mapping. The method further comprises storing the at least a first and second sub-index in different search nodes; receiving a search query; and searching the first tier for result data items relating to the search query.
Yet another aspect of the invention is a system for indexing a database. The system comprises a crawler which crawls the database to find data items. An indexer receives the data items and produces a primary index. A document mapping section maps data items on to at least a first and a second tier based on respective rankings of the data items. A processor produces at least a first and a second sub-index from the primary index based on the mapping. A first search node which stores the first sub-index. A second search node which stores the second sub-index.
Still yet another aspect of the invention is a search node cluster for enabling a search of a database. The cluster comprises search nodes logically arranged in a plurality of columns and plurality of rows. All search nodes in any one of the columns including substantially the same information. All search nodes in any one of the rows including distinct information. The search nodes in the rows being logically divided into at least a first and a second tier. The search nodes in the first tier including an index for a first portion of the database. The search nodes in the second tier including an index for a second portion of the database. The data in the first and second tier is based on respective rankings of the information in the first and second portion of the database.
Yet another aspect of the invention is a search engine comprising a crawler which crawls a database to find data items. An indexer receives the data items and produces a primary index. A document mapping section maps data items on to at least a first and a second tier based on respective rankings of the data items. A processor produces at least a first and a second sub-index from the primary index based on the mapping. A first search node stores the first sub-index. A second search node stores the second sub-index. A dispatch which receives a query and forwards the query to the first search node.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram showing a search engine architecture of the prior art.
FIG. 2 is a diagram showing a cluster of nodes in accordance with the prior art.
FIG. 3 is a block diagram showing a search engine in accordance with an embodiment of the invention.
FIG. 4 is a diagram illustrating the function of mapping documents into tiers in accordance with an embodiment of the invention.
FIG. 5 is a diagram illustrating mapping of documents into tiers and the resulting cluster of nodes in accordance with an embodiment of the invention.
FIG. 6 is a diagram illustrating mapping of documents into tiers and the resulting cluster of nodes in accordance with an embodiment of the invention.
FIG. 7 is a diagram illustrating mapping of documents into tiers and the resulting cluster of nodes in accordance with an embodiment of the invention.
FIG. 8 is a table showing the values for various variables of a fall through algorithm in accordance with an embodiment of the invention.
FIG. 9 is a flow chart showing the operation of a searching algorithm in accordance with an embodiment of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIG. 3 , there is shown a search engine 90 in accordance with an embodiment of the invention. A source of information such as the Internet 100 or other collection of files or documents such as an enterprise or organization network, is crawled by a crawler 102 which, in turn, stores data in a database 108 correspond to the source of information. A document mapping algorithm 114 then maps the documents into tiers as discussed below. An indexer 105 , controlled by a processor 111 , builds a plurality of sub-indices based on the mapped documents in database 108 . A plurality of search nodes in a search node cluster 160 each store respective sub-indices and are each enabled to search their respective sub-indices. A dispatcher 110 sends queries from a user 112 to search node cluster 160 as discussed below.
Recent research yields that there is a skewed distribution of the most popular queries for information on the Internet. For example, most queries (50%–80%) are within the top 1 (one) million most frequently requested queries. Similarly, single days in different months realize an overlap of 80–85% of the same queries. Conversely, only 7% of the queries are asked just once in a similar time period. To take advantage of these facts, the engine uses a disjointed tiered architecture where the indices are not necessarily divided equally.
Referring now to FIG. 4 , each piece of data in database 108 is mapped into one of a plurality of tiers—three tiers are shown in the figure—based on a set of properties. For example, documents which are deemed to have a static relevance ranking, independent of the search query, above a first threshold defined by a database administrator, may be mapped on to Tier I. Documents with a second highest ranking based on another threshold may be mapped to Tier II. As another example, portions of each document or web page can be divided into different tiers. In a particular document, as shown in FIG. 4 , the superior context such as headers and anchors, may be placed in Tier I and the body of the document may be placed in Tier II. The mapping is performed periodically on the data on database 108 .
Referring now also to FIG. 5 , a data structure (not explicitly shown) is stored in dispatch 110 so that search nodes in cluster 160 are logically assigned to particular tiers. After the documents in database 108 are mapped into tiers by document mapping algorithm 114 , indexer 105 produces a plurality of corresponding sub-indices based on the tiers. The sub-indices are stored in respective search nodes in cluster 160 . Cluster 160 includes logical columns 162 a , 162 b , 162 c , etc. and logical rows 164 a , 164 b , etc. of search nodes. While the nodes are shown as being physically disposed in columns and rows, clearly the nodes need not be so physically disposed as long as they are logically arranged in a similar manner.
Search nodes in each column 162 include replications of the same sub-indices so that dispatcher 110 may cycle through a plurality of search nodes. Search nodes in each row 164 include different sub-indices. For example, as shown in FIG. 5 , the search nodes in column 162 a all include information from Tier I. Thus, documents determined to be mapped to Tier I by algorithm 114 , are so mapped, a sub-index is created in indexer 105 , and this sub-index for Tier I is stored in the search nodes in column 162 a.
Similarly, the search nodes in column 162 b include a portion of the information in Tier II. Search nodes in column 162 c include the remainder of the information from Tier II that was not included in the search nodes in column 162 b . Two search node columns are shown for Tier II, and the indices may be split equally among these nodes. Clearly, any number of nodes could be used.
Similarly, search nodes in column 162 d include a portion of the information from Tier III. To facilitate the illustration of cluster 160 , the nodes in each column are shown as being equal in size though it is clear that each node may include the same or a different amount of information than other nodes in the same row. For example, the node in column 162 a , row 164 a will probably have less information than the node in column 162 b , row 164 a because they are in different tiers. As an example of the shown tiered architecture, 1.5 million documents may be indexed in all of the Tier 1 nodes, 6 million documents indexed in all of the Tier 2 nodes, and 10 million documents indexed in all of the Tier 3 nodes.
Each inquiry from dispatch 110 is first searched in the indices of Tier 1 and then the search continues to indices of other tiers based on a fall through algorithm (“FTA”) stored in dispatcher 110 . The FTA determines whether a query should continue to be executed in other tiers and also determines how results from multiple tiers should be merged. Stated another way, the FTA determines the path of the query in the set of tiers based on criteria such as relevance scores and number of hits in a result set. It also determines how many results from each tier can be used before the next tier is consulted.
The FTA uses a plurality of variables to determine whether a next tier should be evaluated including hitlimit, percentlimit, ranklimit, termranklimit, and minusablehits. The variable hitlimit is the evaluation of the number of hits to be used from a tier before a fall-through to the next tier may be forced. For example, for a jump from tier 1 to 2 , the hitlimit may be 1000 and for a jump from tier 2 to 3 , the hitlimit may be 8100. Percentlimit is the maximum percentage of hits from a tier that may be used before fall-through to a next tier may be forced. If the number of hits in a given tier is less than the percentlimit of the requested results overall, a fall-through occurs. For example, for a jump from tier 1 to 2 , the percentlimit may be 10 and for a jump from tier 2 to 3 , the percentlimit may be 30. Termranklimit—if the relevance score of a hit being considered is less than another variable Ranklimit plus the termranklimit value times the number of terms in the query, then fall-through to the next tier is forced. For example, for a jump from tier 1 to 2 , the ranklimit may be 200 and the termranklimit 400. For example, in a two-term query, the relevancy score for a hit to pass this criteria would be 200+(2×400)=1000. For a jump from tier 2 to 3 , the ranklimit may be 0 and the termranklimit 0.
Minusablehits—The number of hits that should pass the above criteria for the FTA for a given tier for there not to be an immediate fall-through to the next tier. This number is typically the number of results presented to a user on a result page. The idea is that if it is known that fall-through will be needed in order to produce the number of hits most often requested, then the fall-through should be done as soon as possible. This variable should be used with a constant value. For example, for a jump from tier 1 to 2 , minusablehits may be 0 and for a jump from tier 2 to 3 , the minusablehits may be 100.
As Tier 2 will only process those queries which pass through Tier 1 , and Tier 3 will only process those queries which pass through both Tiers 1 and 2 , it is desirable that Tier I have the highest performance nodes. Extra capacity at Tiers 2 and 3 may be achieved by replicated columns or by reducing the number of documents at each node.
In the embodiment in FIG. 5 , a 1 dimensional tier-ing configuration is used in that all documents and corresponding indices are distributed using a static relevance score. For instance, the static relevance score may be based on link cardinality, link popularity, or site popularity on the web.
For example, in a database of one billion records, the top 30 million documents, based on static relevance, are mapped to Tier 1 , the next 360 million documents are mapped to Tier 2 and the following 610 million documents mapped to Tier 3 . One drawback to this configuration is that using static relevance is only part of the overall formula used for determining a relevant document.
Referring now to FIG. 6 , there is shown another cluster of nodes 170 in accordance with the invention. Cluster 170 could be used in place of cluster 160 and includes nodes in columns 172 a , 172 b etc. and rows 174 a , 174 b , etc. In this embodiment, a 1.5 dimensional configuration is realized. A query log is run for the 1 million most common queries for a period of time. The first 20 hits for each of the one million queries are mapped to Tier 1 as shown at 176 in FIG. 6 . This may be approximately five million documents. The remaining documents are distributed according to a static relevance score. For example, for a billion document database, the top 30 million documents are mapped to Tier 1 (with 5 million of those documents being locked into this tier), 360 million documents mapped to Tier 2 and 610 million documents mapped to Tier 3 . A FTA is used as discussed above.
Referring now to FIG. 7 , there is shown another cluster of nodes 180 in accordance with the invention. Cluster 180 can be used in place of cluster 160 and includes nodes in columns 182 a , 182 b etc. and rows 184 a , 184 b , etc. In this embodiment, a 2 dimensional configuration is realized. In the embodiment of FIG. 7 , the same tier distribution as the 1.5 dimensional configuration of FIG. 6 is optionally used. However, information in high value contexts for all documents is searched first simultaneous with Tier I. These high value contexts are the most important portions of the respective web pages when determining dynamic relevancy of a document. These portions include the title, anchors, etc.
If more hits are needed, the full index is continually searched using the multi-tier configuration while removing duplicates from the returned results. For example, the body context of the top 30 million documents (with 5 million locked as discussed above) are mapped to Tier 1 , the body context of the 360 million documents mapped to Tier 2 and the body context of the 610 million documents mapped to Tier 3 . A new Tier 0 is used which includes the superior context of all 1 billion documents. Some values for the variables of the FTA for the architecture of cluster 180 , is shown in FIG. 8 . An optional tier 4 may be used with low value documents. Such documents may be pure links or spam documents. By searching the high volume contexts of all the tiers in tier 0 , the invention takes advantage of the fact that searching a relatively small subset of the information in the tier 2 and tier 3 nodes is much cheaper than searching the full information indexed in these nodes.
Referring now to FIG. 9 , there is shown a flow chart summarizing some of the operations of the invention. At S 2 , a search engine crawls a data source. At S 4 , documents gathered from the data source are stored in a database. At S 6 , the documents are divided into tiers using one of the algorithms discussed above. At S 8 , the documents are mapped into the determined tiers. At S 10 , sub-indices are produced based on the determined tiers. At S 12 , the sub-indices are stored in respective search nodes in a search node cluster. At S 13 , a search query is received from a user. At S 14 , the search engine searches the indices in Tier I. At S 16 , based on the FTA, the search engine searches Tier II search nodes and any other Tier search nodes. At S 18 , results of the search are provided for a user.
Thus, by mapping documents crawled in a database into disjointed tiers, a faster, more cost effective search engine is realized. Further, by providing a fall through algorithm that dynamically determines how many of these tiers are searched, scaling of the database is improved.
While the invention has been described and illustrated in connection with preferred embodiments, many variations and modifications as will be evident to those skilled in this art may be made without departing from the spirit and scope of the invention, and the invention is thus not to be limited to the precise details of methodology or construction set forth above as such variations and modification are intended to be included within the scope of the invention. | A search engine comprising a crawler which crawls the WWW and stores pages found on the WWW in a database. An indexer indexes the pages in the database to produce a primary index. A document mapping section maps pages in the database into a plurality of tiers based on a ranking of the pages. The ranking may be based on portions of the pages which have a relatively higher value context. A processor produces a plurality of sub-indices from the primary index based on the mapping. The sub-indices are stored in a search node cluster. The cluster is a matrix of search nodes logically arranged in a plurality of rows and columns. Search nodes in the same column include the same sub-index. Search nodes in the same row include distinct sub-indices. A search query received by a user is sent to a dispatcher which, in turn, forwards the query to the first tier of search nodes. A fall through algorithm is disclosed which indicates when the dispatcher should forward the search query to other tiers of search nodes. | 8 |
[0001] This application claims the benefit of U.S. provisional patent application No. 60/600,828 filed Aug. 10, 2004 entitled Injection Molded Paddle Blade, which is hereby incorporated by reference in its entirety for all purposes.
TECHNICAL FIELD
[0002] The present disclosure relates to a paddle blade for a self-propelled watercraft molded by a gas-assisted injection molding process.
SUMMARY
[0003] A paddle blade for use in watersports is provided. The paddle blade includes: a shaft interface portion; a stiffening spine; and a blade portion including a fan-shaped tapered portion, a tip region and blade edges; wherein a hollow region is defined in the blade portion extending through the fan-shaped tapered portion toward the tip region but short of the blade edges.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] FIG. 1 is a view of the underside of a first embodiment of a gas assisted injection molded blade for a paddle, showing the hollow region.
[0005] FIG. 2 is a side elevation view of the embodiment of FIG. 1 .
[0006] FIG. 3 is a plan view of the upper side of the embodiment of FIG. 1 .
[0007] FIG. 4 is a view of the underside of a second embodiment of a gas assisted injection molded blade for a paddle.
[0008] FIG. 5 is a side elevation view of the embodiment of FIG. 4 .
[0009] FIG. 6 is a plan view of the upper side of the embodiment of FIG. 4 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0010] The present disclosure relates to a novel blade for a paddle for a self-propelled personal watercraft such as a kayak, and a novel paddle having at least one blade. Generally, gas assisted injection molding is used to form a paddle blade (shown at 10 in FIGS. 1-3 ) having improved buoyancy, stiffness, anti-cavitation characteristics, and other performance features compared to prior paddle blades. In particular, in some embodiments, gas assisted injection molding is used to form a paddle blade with a unique combination of a stiffening spine formed along a first portion of the blade, shown at 12 in FIGS. 1-3 , and a fan-shaped extension/taper of the stiffening spine, shown generally at 14 , along the remainder of paddle blade 10 . Fan-shaped extension/taper 14 allows an area of paddle 10 to include a hollow region 16 with improved buoyancy. Furthermore, fan-shaped extension/taper 14 of stiffening spine 12 acts as a double airfoil, providing lift to aid in the removal of paddle blade 10 from the water and during a paddle stroke.
[0011] Careful control of the temperature zones of the injection mold during the injection molding process allows the hollow region to be formed. The outer area of the mold, near a tip region 18 of blade 10 , is maintained at a higher temperature than a shaft interface 20 (i.e. where the paddle shaft meets the blade) of the mold so that resin at the tip region of the mold remains at a low enough viscosity for the gas injected into the mold to form a gas bubble near the tip region of the mold. The nominal wall thickness of the paddle (i.e. the thickness between the hollow interior and the exterior) in some embodiments is approximately ⅛ inch, but may be either greater or lesser than this. Furthermore, the walls may be thinner in the tip region 18 of paddle 10 than in other regions.
[0012] Paddle blade 10 also is lighter weight than known gas assisted injection molded paddles due to the hollow tip and spine structure. For example, paddle blade 10 has a mass of approximately 300 grams, whereas another gas assisted injection molded paddle blade of a substantially similar size having a solid tip and different stiffening structure than stiffening spine 12 was found to have a mass of approximately 370 grams. Furthermore, paddle blade 10 was found to have a buoyancy of 49 grams, centered about tip region 18 , whereas the other blade was found to have a buoyancy of only 11 grams, centered about its shaft interface. Therefore, paddle blade 10 offers superior buoyancy at its tip, thereby offering superior assistance in removing the paddle blade from the water at the end of a stroke.
[0013] As shown in FIG. 1 , stiffening spine 12 is appears on the back face of the paddle, and in the depicted embodiment extends approximately ⅔ the full length of paddle 10 . Hollow spine 12 provides a channel for material and gas flow from shaft interface 20 to tip region 18 , and is the primary structure for paddle rigidity, and retention of form. Tip region 18 , representing approximately ⅓ of the full length in the depicted embodiment, fans out to meet the blade edges. This results in the unique visual form, provides stiffness to the tip region of paddle 10 and additional structural support to the blade edges. It also results in a hollow region that extends symmetrically through the blade.
[0014] The fanned profile of tip region 18 has a section profile described as two opposing airfoils. These airfoils provide lift to the paddle during the paddle stroke, increasing paddle efficiency and reducing user strain. It also provides lift to the paddle as it exits the water, reducing the energy required for the user raise the blade at the end of paddle stroke. This airfoil and lift minimizes splash during entry and exit of paddle into water, reducing incidental wetness of the user. It also provides low resistance of the paddle during entry and exit modes of the paddle stroke, thereby reducing user strain.
[0015] The fact that the hollow region 16 extends through stiffening spine 12 and toward tip region 18 results in a paddle blade that is positively buoyant. Buoyancy is centered about tip region 18 , which is where buoyancy has the greatest effect on paddle performance. Buoyancy provides upward momentum to the paddle as it exits the water, reducing the energy required for the user to raise the blade at the end of the paddle stroke. Buoyancy counteracts the overall weight of the paddle in use, reducing user strain.
[0016] Paddle blade 10 represents an ideal relationship of size and length of the hollow spine, and fan shaped tip, providing a continuous structure for the full length of the paddle blade for retention of form, rigidity in use, and durability. It also results in minimal material usage and overall paddle weight, matching or less than existing designs, while providing the additional maximization of positive buoyancy. Moreover, this design provides minimum cavitation of water throughout the entire stroke. Cavitation severely reduces efficiency during the paddle stroke. Cavitation may be induced in normal use by the articulation of the spine, which in this design is most severe at the shaft and blending into the relatively flat, fan shaped tip profile that has no relative articulation.
[0017] In the embodiment of FIGS. 1-3 , stiffening spine 12 and fan shaped extension/taper 14 are generously blended into the blade faces and ultimately to tip region 18 , resulting in a form devoid of severe articulations. This minimizes cavitation of water throughout the entire stroke, and minimizes cavitation of water during slicing modes of paddle use; i.e., during entry and exit of the paddle into the water, and during bracing and draw strokes.
[0018] The embodiment of FIGS. 1-3 further represents an ideal relationship of tip location, power face dihedral, and back face geometry including blade edges, hollow spine, and hollow fan tip. From the end view of the paddle, the relationship of blade edge height, maximum dihedral on the power face, and maximum spine height on the back face minimizes water cavitation during slicing modes of paddle use by allowing positive flow along all surfaces. During modes of paddle use where water pressure is normal to the power face, the dihedral curvature on the power face equally directs water flow from the center line to the edges of the paddle. This effectively stabilizes the paddle as it travels through the water reducing the tendency flutter from side to side which reduces user strain. Cavitation of water is minimized as the flow wraps around the blade edges and meets along the spine on the back face of the blade. During the entire paddle stroke, the tip position and its relation to the paddle blade curvature directs water flow toward the tip of the blade, which results in superior paddle efficiency. It also results in positive water flow toward the tip along all blade surfaces, minimizing the occurrence of water cavitation, and maximizing paddle efficiency. Moreover, the tip position, its relation to the paddle blade curvature, and the power face dihedral results in a rapid shedding of water during the exit mode of the paddle stroke. This minimizes user strain and reduces incidental wetness of user during the paddle stroke.
Embodiment of FIGS. 4 - 6
[0019] Another embodiment of a gas assisted injection molded blade, is shown at 100 in FIGS. 4-6 . Therefore, as showing in FIG. 4 , a hollow region 116 is shown to extend through stiffening spine 112 , fan-shaped extension/taper 114 , tip region 118 , all the way out to adjacent blade edges 122 . In the depicted embodiment, hollow region 116 extends to within one half inch of the blade edges 122 , although in the same embodiment it might extend only to within three-quarters of an inch. Corresponding numbers have been used for this embodiment, except that they are in the 100 series. In this second embodiment 100 , the entire blade is hollowed by a gas assisted injection molded process. Blade 20 may include stiffening ridges or depressions (not shown) formed along the length or width of the blade to impart greater rigidity to the blade. This paddle blade 100 would increase buoyancy, reduce the occurrence of water cavitation, reduce water splashing and user wetness, on entry and exit. It will also improve paddle stroke efficiency by providing the maximum amount of airfoil lift for the exit portion of the stroke.
[0020] Each of the depicted embodiments are designed to be used with a paddle shaft 24 or 124 and paddle handle 26 or 126 , although these have only been schematically depicted in the figures.
[0021] Variations may be made that will be obvious to those skilled in the art. Such variations are intended to be covered by the claims that follow. | A paddle blade for use in watersports is provided. The paddle blade includes: a shaft interface portion; a stiffening spine; and a blade portion including a fan-shaped tapered portion, a tip region and blade edges; wherein a hollow region is defined in the blade portion extending through the fan-shaped tapered portion toward the tip region but short of the blade edges. | 1 |
CROSS REFERENCE TO RELATED APPLICATION
[0001] This non-provisional application claims priority to the provisional application for patent Ser. No. 60/665,681 which was filed on Mar. 28, 2005.
BACKGROUND OF THE INVENTION
[0002] This invention relates generally to the mounting of a lighting fixture, and more specifically pertains to a conversion connector that provides for the changing of a ceiling lamp, such as a recessed light, to a hanging style of lamp that can be easily changed, at the desire of the occupant, so as to convert quickly the style of decorative light hanging within a facility.
[0003] Lighting for the home, business installation, a restaurant, night club, bar, or any other business establishment, has long been available in the art. Of more recent vintage, though, the use of recessed lighting has become quite in vogue over the past twenty-five to thirty years. Recessed lighting can now be found in restaurants, taverns, even in business establishments, where the lights are mounted into a false ceiling, and such type of recessed lighting has even become stylish for installation into the residential building. Such lighting is not only attractive, but has been readily accepted by the home or business owner, to sustain its popularity.
[0004] Furthermore, in earlier years, a suspended or hanging type of light was of interest to particularly the homeowner, where a suspended light could be located over an end table, kitchen table, dining table, or any other location, where more proximate lighting was desired. But, when recessed lighting is installed within a facility, few means exist to allow an owner to convert from that type of lighting, to a suspended or hanging lamp, when desired.
[0005] A variety of patents have issued upon various types of lighting systems. For example, the U.S. patent to Miller, U.S. Pat. No. 4,046,448, shows a lighting fixture accessory, which is basically a telescoping type of housing for use for supporting a light socket, so that the housing can be expanded, or contracted, as desired, within a light socket of a facility.
[0006] The U.S. patent to Aubrey, U.S. Pat. No. 4,327,402, shows another light fixture. In this particular instance, the light fixture and its housing can be extended downwardly, by disengaging various latches, to allow for a lengthening of its light support, to bring the light either closer to the source of usage, or it can be contracted back up towards the ceiling, as desired.
[0007] The U.S. patent to McNair, U.S. Pat. No. 4,595,969, shows a lamp mounting apparatus and method. This apparatus is identified as for use for fitting within a recessed type of lighting fixture. But, the reflector of the shown light actually fits against the cover of a recessed receptacle, of the recessed lighting, and does not really provide for any extension or hanging of a lamp therefrom, because it appears that the reflector is originally connected up to and against the recessed fixture, during its assembly.
[0008] The patent to Zelin, U.S. Pat. No. 4,807,099, shows another lighting fixture. This particular device, as with some of the previously patented devices, is more concerned with furnishing fluorescent lighting, and its fixture, that may be interchangeable with an incandescent lighting fixture, that is recessed within the ceiling. As can be seen, it appears that the lighting fixture of this invention incorporates a lip adapter, which apparently is intended to conform to the light fixture that is mounted into the ceiling, of the recessed lighting installation, and not as a hanging lamp.
[0009] Another U.S. patent to Aubrey, et al., U.S. Pat. No. 4,956,758, shows a lamp mounting apparatus and method. Once again, this particular lamp mounting apparatus provides means for converting from an incandescent to a fluorescent type of light. In its design, it incorporates its fixture, to fit within the conventional recessed lighting fitting, so that its shoulder will bias against the recessed housing. And, the fluorescent lighting is then hardwired through wiring, into the ceiling, and connected through its screw connector, into the recessed lighting socket. Once again, this device relates to a lamp mounting apparatus, rather than means to provide for exchanging of a hanging lamp, into a recessed lighting fixture.
[0010] Finally, the published application of Wu, No. US 2003/0235049, shows a decoration bulb assembly. This device does not appear to relate to any type of recessed lighting fixture, but rather, simply discloses a decorative type of bulb, that emanates from its adapter, that can simply be screwed directly into a socket, at the ceiling or surface level of the facility. This does not relate to any type of an extension or converter for furnishing support, structurally, for a hanging lamp, from a recessed lighting fixture.
SUMMARY OF THE INVENTION
[0011] This invention relates generally to a hanging light conversion connector, and more specifically to a uniquely designed connector that can plug into a recessed lighting receptacle, and convert the lighting to a suspension or hanging lamp, at the desire of the occupant.
[0012] As previously stated, in reviewing the background of this invention, recessed lighting has long been available in the art. The concept of this invention is to convert the recessed light, to a hanging lamp, so that a variety of lamps, and their particular designs or ornamental appearances can be changed, at the selection of the occupant, as desired. For example, hanging lamps can be applied that reflect the seasons of the year, as within a restaurant, a sports bar, and the like. Or, depending upon the game to be televised in the sports bar for that day, the hanging lamps could be installed that display the various competing teams' colors, emblems, or the like, to add to the enthusiasm of the crowd.
[0013] In its primary construction, the concept of this invention is to replace the flood lamp, of a recessed light, with a hanging light fixture. The hanging light fixture can be screwed into the recessed lighting socket. Essentially, this invention is a type of uniquely designed screw-in plug, that can be threadedly engaged into the light fixture, even up in its recessed area, and the connector can have a screw-in type of plug, of the type that a lighting fixture can be hardwired to, and connected to its base, for support for the hanging lamp, during installation. The connector has a light type socket, provided at its bottom, and the wires from the lamp will extend into its opening, and be hardwired therein. Then, the double ended threaded connector will rotate its threads into the upper end of the socket, and the other threaded end of the double plug can rotate its threads directly into the socket provided in the removed recessed light. A hanging lamp can then be screwed directly into the socket for the recessed lighting fixture. Thus, when the light switch for the recessed light is turned on, the hanging lamp will light, to provide for illumination, and the reflection of the design, indicia, or coloration, that is desired for the style of hanging lamp connected thereto. As stated, in this manner, a variety of hanging lamps can be interchanged, for displaying something that may bring lighting closer to the user, or to add to the decorativeness of the facility.
[0014] It is, therefore, the principal object of this invention to provide means for converting a recessed light fixture into a support and electrical connector for a hanging lamp, or a variety of hanging lamps for use in a facility, or even a house.
[0015] Still another object of this invention is to provide a conversion connector for a hanging lamp, that may be threadedly engaged directly into the socket of a recessed light, and thereby provide for not only the conversion of the lighting to a hanging lamp, but one that may be changed multiple times to vary the attractiveness and decorativeness of the lighting for the facility in which such hanging lamp is installed.
[0016] Yet another object of this invention is to provide a conversion connector that may be integrated into a thread-in plug, and yet provide terminals for hardwiring a hanging lamp thereto, when converting recessed lighting to a hanging lamp, within a facility or home.
[0017] Yet another object of this invention is to provide a conversion connector that can be promptly and easily installed, for changing residential or commercial lighting into the hanging style lamp.
[0018] These and other objects may become more apparent to those skilled in the art upon review of the summary of the invention as provided herein, and upon undertaking a study of the description of its preferred embodiment, in view of the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] In referring to the drawings,
[0020] FIG. 1 shows a prior art recessed lighting fixture, and its flood lamp, installed within a ceiling;
[0021] FIG. 2 shows the conversion of the recessed lighting fixture into an electrical and structural support for a hanging lamp;
[0022] FIG. 3 shows the conversion connector, enlarged, as disclosed in FIG. 2 ;
[0023] FIG. 4 shows the double ended plug removed from the light socket for the hanging lamp;
[0024] FIG. 5 shows an exploded view of the double ended threaded plug, with the electrically conductive tabs arranged intermediate thereof, and which can be threadedly engaged within the lamp socket for the hanging lamp;
[0025] FIG. 6 shows a modification to the hanging light conversion connector of this invention;
[0026] FIG. 7 discloses the modified conversion connector, in partial exploded view, having the electrical wiring from the hanging lamp extending into the connector and connecting with the terminal tabs of the socket plug; and
[0027] FIG. 8 is a perspective view of a type of shade that may be applied to the end of the hanging lamp to provide cover for the light, and to display various types of other decoration, such as emblems for sport teams, etc.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0028] In referring to the drawings, FIG. 1 shows the standard style of recessed lighting fixture, as at 1 , which has a socket 2 , holding a lamp 3 , as may be installed. The housing 4 for the recessed fixture secures to the socket base 5 , at its upper end, and at its lower end, normally includes flanges, or at least a continuous flange, as at 6 , and which supports or connects with the ceiling material 7 normally of a suspended ceiling structure.
[0029] FIG. 2 shows similar type of structure, for a recessed lighting fixture, but in this instance, includes the conversion connector 8 that threadedly engages within the socket 2 , and provides for suspending of the hanging lamp 9 .
[0030] The conversion connector of this particular invention is also shown in FIGS. 3 and 4 . It includes a double ended threaded engaging plug, the two plugs being connected back to back, as can be seen at 10 and 11 . Normally, each of these plugs are of the standard type, which includes its threaded segment 12 which in this instance, can threadedly engage directly into any socket 2 for a recessed lamp, while the other plug likewise includes a series of threads, as at 13 , and which can thread directly into a light socket, as at 14 , of the type as known in the art. When the conversion connector is assembled in this manner, the electrical wires 15 from the hanging lamp, can be connected into the connector, internally, thereat as known in the art, and the double plug can then be threadedly engaged therein, within the light socket 14 , but also into the socket 2 for the recessed lighting fixture, to provide for an instant conversion of the flood lamp 3 , into a hanging lamp, and as previously explained, with respect to FIG. 2 .
[0031] The specific construction of the conversion connector 8 , as previously explained, can be seen in FIG. 5 . Each of the threaded plugs 10 and 11 , as known, at their flanged ends, as at 16 and 17 , have their plug in openings 18 and before these two plugs are sealed together, either by adhesive, or molding, as along the surface of their flanges 16 and 17 , the electrical conducting tabs 19 and 20 are inserted into their respective plug in locations, as at 18 , to provide for electrical connection from the upper threaded plug 10 , to the lower plug 11 , once assembled and installed. The bottom portion of the conversion connector includes, what was previously identified as the light socket 14 , and includes the base of the socket 21 , having an opening at its lower end, as at 22 , through which the electrical wiring 15 from the light fixture extends.
[0032] The pair of wires then connects by threaded fasteners, as at 23 and 24 , to the base 25 of the threaded socket 26 , as known in the art. Then, the upper part of the light socket, as at 27 , is lowered to surround the threaded socket 26 , and then threadedly engages onto the sleeve threads 28 of the lower portion 21 of the light socket, as can be seen. When the entire unit is assembled, so that it appears as shown in FIGS. 3 and 4 , the double socket plugs 10 and 11 are then threaded into the sleeve threads 26 , to provide for electrical connection completely through the conversion connector, which is then readily assembled for installation into the recessed lighting fixture socket 2 , as described.
[0033] Thus, when assembled in that manner, the entire conversion connector has the appearance as shown in FIG. 2 , it is generally concealed within the housing 4 of the recessed lighting fixture, and is not that observable to any occupant of the room, in which the hanging light fixture is located. In fact, because the light fixture 9 may have the variety of colors, designs, indicia, or other pictures applied thereto, the line of vision of the room occupant will be towards the fixture, and not up into the ceiling, as can be understood. While it is not shown, any type of reflector, or cover, can be applied at the base of the conversion connector, so as to cover the opening into the recessed lighting fixture housing 4 , to provide greater concealment for the electrical installation. In addition, to provide greater support for the hanging lamp 9 , a fastener, as at 29 , may be provided at the bottom of the lamp socket, and be tightened about the wires, to support them in position, and to aid in supporting the weight of the hanging lamp fixture 9 , once installed. Or any type of chain or other support can be applied, as known in the art.
[0034] FIGS. 6 and 7 disclose a further variation upon the conversion connector of this invention. The conversion connector, as shown at 30 , includes the lower structure of the light socket, as can be seen at 31 , and has a threaded plug 32 secured thereto, by means of an adhesive or other connection between their flanges 33 and 34 , when connected together. Thus, when assembled in this manner, it can provide for electrical connection within the recessed lighting fixture, and its socket 2 , but at the same time, support a hanging lamp, in the manner as previously described. Hence, because it may be desirable to separate the threaded plug 32 , from the lamp base 31 , the inner connection between the flanges 33 and 34 may be through a threaded connection, so that they may be unthreaded, for separation, to allow one to attain access into its internal electrical connectors, as can be seen in FIG. 7 . As noted, the threaded plug 32 has its receptacle slots 35 provided therein. And, the electrical tabs 36 extend into the receptacles, to provide for electrical connection. Then, the electrical wires 37 from the hanging lamp can be fastened to each of the electrical tabs 38 and 39 , so to conduct charge through the plug 32 , from the socket 2 , and through the electrical tabs 36 , through the connected electrical wires 37 , and to the hanging light fixture, to provide for its illumination, when charge is being conducted. In addition, once again, a fastener, as at 40 , can secure the electrical wires 37 , or an associated chain, to hold them in position, and to support the weight of any light fixture suspended therebelow.
[0035] In addition, it may be just as likely that the flanges 33 and 34 of the threaded plug 32 , and the lamp housing 31 , can be threadedly engaged together, in a manner similar to that which the upper socket housing 27 threadedly engages onto the threaded sleeves 28 , of the lamp socket 14 as disclosed in FIG. 5 .
[0036] As shown in FIG. 8 , this is an example of the type of shade that may be applied to the hanging lamp connector, at the lower end of its cord, and where the lamp will plug into the same. The type of shade or reflector that may be applied to the lamp, as previously described in FIG. 2 , indicated at reference character 9 . Different types of shades, globes, or any other types of reflector, that may bear indicia of different sport teams, community sites, even the name of the nightclub or restaurant, or any type of nomenclature, as desired by the owner, can be used. As can be seen, in FIG. 8 , shade 41 includes the usual frame 42 , for supporting the shade covering 43 , and the means for connection of the shade to the wires 15 , 37 , or even any chain that suspends from the connector 8 , includes the supporting ring 44 . In this particular instance, the supporting ring 44 includes a slot 45 , and through this slot the cord will be applied, and then can be secured by any type of a fastener or any type of a threaded connecting means, that can hold the cord or chain to the ring 44 , in suspension. The end of the electrical wires is a common type of screw in socket, similar to what has been described with respect to the light socket 14 , but will be located at the opposite end of the wires, at its downward most point, and where the lamp will be reapplied, and one of the lamps, bowls, reflectors, such as 9 , or shade 41 , is applied thereat, for surrounding the light, and allow for projection of any applied indicia, trademarks, and the like.
[0037] It must also be commented herein that the type of hanging lamp conversion connector, is described as connecting within a recessed lighting fixture, could also be applied to any light socket in a ceiling, where it is desired to suspend a hanging lamp, in lieu of the ceiling light, to add to the decorativeness of the installation. Thus, in many old homes, and even contemporary ones, where light sockets are applied at ceiling level, regardless whether they are recessed or not, could use this conversion connector as a means for suspending and operating a hanging lamp, rather than a ceiling mounted fixture. This is an example as to how this conversion connector can be applied.
[0038] Hence, the essence of this invention is to provide a conversion connector, which has not been available in the prior art, and is not known to be available for use for converting a recessed lamp into a hanging lamp fixture, in the manner as described herein. Through the use of this type of conversion connector, the type of assembly, its installation, and replacement with another hanging lamp, can be readily achieved as described herein, for the installation as shown and explained.
[0039] Variations or modifications to the subject matter of this development may occur to those skilled in the art upon review of the invention as described herein. Such variations, if within the spirit of this development, are intended to be encompassed within the scope of the invention as explained. The description of the preferred embodiment and as shown in the drawings, are set forth for illustrative purposes only to show the principle of this hanging lamp conversion connector. | A hanging lamp conversion connector for supporting a suspended lamp, and which can threadedly engage within the socket of a recessed lighting fixture, once its lamp has been removed, provides for an instant conversion of a recessed light or ceiling socket to a hanging lamp, for installation within any facility. It includes a housing, of a light socket, into which a single or double threaded plug may locate, and which provides an upward orientation of the upper threaded plug with a light socket for threading directly into the recessed lighting fixture, for installation. Such a connector can be easily removed, by unthreading the lamp and the lamp can be replaced with another, or a different reflector, or shade, to add to the variety of uses and multiple displays associated with a variety of suspended and hanging lamps. | 7 |
RELATED APPLICATION
[0001] The benefit of the filing date of applicant's provisional patent application Ser. No. 60/795,095 filed Apr. 26, 2006 is requested under 35 U.S.C. §120.
FIELD OF THE INVENTION
[0002] This invention relates to film used to manufacture pouches and bags for containing flowable material. The film is made of low density polyethylene and can be formed into a monofilm or a multi-layer film that can be used to produce packages that exhibit improved flex crack resistance.
BACKGROUND OF THE INVENTION
[0003] Flex crack resistance is an extremely important property for film used in bags and pouches that are formed into packages for flowable materials, particularly for liquids, and most particularly for non-viscous liquids like water, milk, juices, and the like. These liquids can slosh around considerably during package manufacturing, handling and transportation causing flexing of the film and flex cracking for most of the commonly used film materials.
[0004] Flex cracking is caused by the movement of the liquid within the pouch or bag, and is most likely to happen where the film is in close proximity to the upper surface of the liquid. Flex cracking can occur during shipping and handling of even the smallest fluid-containing pouches. Flex crack pinholes result in at least loss of oxygen and moisture barrier, reducing the shelf life potential of the product, and often in loss of the hermetic seal, rendering the product unsafe to use if it is a food product. Generally a Flex Crack Resistant Film is one that should develop 10 or less pinholes per 300 cm 2 in 20,000 cycles of Gelbo Flex testing, and preferably 5 or less pinholes per 300 cm 2 in 20,000 cycles.
[0005] It is well known that film made from a lower density polyethylene will have better flex crack resistance than film made from a higher density polyethylene. In this regard, reference may be had to the disclosures of WO 95/26268. It is also well known that film made from a lower density polyethylene will have inferior thermal resistance and stiffness than film made from a higher density polyethylene. Reference in this instance may be had to the disclosures of US 2005/0131160 published Jun. 16, 2005, the disclosure of which are incorporated herein by reference. However, what is not well understood is how to modify the composition of a polyethylene film to maximize the improvement in flex crack pinhole resistance, while at the same time minimizing the negative effect on thermal resistance and stiffness, which are generally desirable film properties.
[0006] Film with inadequate thermal resistance may stretch and deform unacceptably in close proximity to heated machine parts such as sealing jaws found in form, fill and seal machines. The stretched or deformed area of the film may become the weak point of the pouch or bag, at which it will fail prematurely in subsequent shipping and handling. Aqueous products are a major portion of those products packaged in pouches and bags. As water boils at 100° C., thermal stability at temperatures just above 100° C. is therefore desirable in a pouch or bag film.
[0007] Bending stiffness may, or may not, be important to the performance of the pouch or bag, depending on the end use. Pouches, which are to stand up in a pitcher and pour without flopping over to restrict fluid flow, need a minimum level of bending stiffness. Film also requires a certain amount of bending stiffness to run through form-fill-seal equipment effectively, without conforming too closely around forming collars, stationary guides and rollers so that it stretches and distorts. Bending stiffness depends on the thickness of the film and its tensile modulus. As economics drive industry to downgauge films further and further, tensile modulus becomes more and more important in achieving adequate bending stiffness. The minimum tensile modulus for a thin pouch or bag film that is used on form-fill-seal equipment should be 20,000 psi, and 25,000 psi may also be used.
SUMMARY OF THE INVENTION
[0008] Surprisingly, it has been found that blending ultra low density polyethylene (ULDPE) as a very minor component in a variety of low density ethylene homopolymers and interpolymers, leads to a film with particularly good flex crack performance. This desirable effect is achieved with very little negative impact on the thermal resistance and stiffness of the film.
[0009] There are many disclosures of combinations of ultra low density polyethylene polymers (ULDPE) with linear low density polyethylene polymers. An example can be found in U.S. Pat. No. 5,508,051 which discloses such a combination. However, the combination proposed requires at least 10% by weight of the ULDPE component and further, does not address the problem of flex cracking.
[0010] The prior art provides little direction on how to control or eliminate flex crack in films used for packaging of flowable materials, in particular liquids. The present invention while utilizing a known combination of polymers now provides specific direction on how they should be combined to deal with flex cracking in the resultant films. Further it is surprising that this combination offers the right balance of properties with respect to flex cracking, thermal resistance and stiffness that not only allows its use in the making of pouches and bags for containing flowable materials, but also permits the film to be downgauged in thickness. Thus the film possesses a desirable resistance to flex cracking, good performance in typical pouch and bag requirements and a commercial cost advantage because of the downgauging capability. The film of the invention may be used on its own as a monofilm or may be incorporated into a multi-layer structure or into a multi-ply film structure, where its flex crack resistance provides the whole film with this property at a suitable level.
[0011] In one aspect of the invention there is provided a sealant film for use in a film structure for the manufacture of pouches and bags, for containing flowable materials, the sealant film comprising 1) from about 2.0 to about 9.5 wt %, based on 100 wt % total composition, of an ethylene C 4 -C 10 -alpha-olefin interpolymer having a density of from 0.850 to 0.890 g/cc and a melt index of 0.3 to 5 g/10 min, the interpolymer being present in an amount that optimizes flex crack resistance as measured using a Gelbo Flex tester set up to test in accordance with ASTM F392, and minimizes reduction of thermal resistance, as measured using DSC (ASTM E794/E793) Differential Scanning Calorimetry (DSC) which determines temperature and heat flow associated with material transitions as a function of time and temperature, and stiffness of the sealant film layer as measured using Tensile Modulus of the polyethylene films measured in accordance with ASTM Method D882; 2) from about 70.5 wt % to about 98.0 wt %, based on 100 wt % total composition, of one or more polymers selected from ethylene homopolymers and ethylene C 4 -C 10 -alpha-olefin interpolymers, having a density between 0.915 g/cc and 0.935 g/cc and a melt index of 0.2 to 2 g/10 min; 3) from about 0 wt % to about 20.0 wt %, based on 100 wt % total composition, of processing additives selected from slip agents, antiblock agents, colorants and processing aids; and the sealant film has a thickness of from about 5 to about 60 μm.
[0012] Flex Crack Resistance is assessed by means of the Gelbo Flex Tester referenced above. Optimization means that pin holes are 10 or less per 300 C 2 in 20,000 cycles of Gelbo Flex testing. Pin holes of 5 or less are more optimal. As for minimizing reduction of thermal resistance, ideally this resistance is at temperatures that are as close as possible to 100° C. The Examples provide guidance with regard to the limits here. These two parameters require balancing to achieve the desired result. The person skilled in the art can readily ascertain from the test results as set out where the balance lies for a particular film.
[0013] More particularly, the present invention provides a sealant film for use in a film structure for containing flowable materials, the sealant film comprising 1) from about 2.0 to about 9.5 wt %, based on 100 wt % total composition, of an ethylene C 4 -C 10 -alpha-olefin interpolymer having a density of from 0.850 to 0.890 g/cc and a melt index of 0.3 to 5 g/10 min, the interpolymer being present in an amount such that the film structure develops 10 or less pinholes per 300 cm 2 in 20,000 cycles of Gelbo Flex testing, as measured using a Gelbo Flex tester set up to test in accordance with ASTM F392, and has a thermal resistance at temperatures just above 100° C., as measured using DSC (ASTM E794/E793) Differential Scanning calorimetry (DSC) which determines temperature and heat flow associated with material transitions as a function of time and temperature, and a minimum tensile modulus of 20,000 psi as measured using Tensile Modulus of the polyethylene films measured in accordance with ASTM Method D882; 2) from about 70.5 wt % to about 98.0 wt %, based on 100 wt % total composition, of one or more polymers selected from ethylene homopolymers and ethylene C 4 -C 10 -alpha-olefin interpolymers, having a density between 0.915 g/cc and 0.935 g/cc and a melt index of 0.2 to 2 g/10 min; 3) from about 0 wt % to about 20.0 wt %, based on 100 wt % total composition, of processing additives selected from slip agents, antiblock agents, colorants and processing aids; and the sealant film has a thickness of from about 5 to about 60 μm.
[0014] In another form of the invention, the sealant film has a minimum tensile modulus of 20,000 psi.
[0015] In another aspect of the invention, there is provided a multi-layer film for use in making pouches for packaging flowable material having improved flex crack resistance wherein the sealant layer is as described above and has a thickness of from about 2 to about 50 μm.
[0016] In yet another aspect of the invention there is provided a multi-layer film for use in making pouches having improved flex crack resistance wherein one or both of the outer layers is the monofilm as described above.
[0017] In a further aspect there is provided a multi-ply film structure for use in making bags having improved flex crack resistance for packaging flowable material, which has an intermediate or inner ply of the monofilm as described above having a thickness of from about 20 to about 125 μm.
[0018] The ethylene C 4 -C 10 -alpha-olefin interpolymers 1) and 2) may each be octene interpolymers. Component 3) may comprise from about 3 to about 5 wt % based on 100 wt % total composition.
[0019] In another aspect of this invention there is provided an improved pouch making process comprising the steps of forming a film structure as described above; forming the film structure into a tubular member; heat sealing longitudinal edges and then filling the pouch with flowable material; heat sealing a first transverse end of the tubular member to form a pouch; and sealing and cutting through a second transverse end of the tubular member to provide a filled pouch. The tubular member may be filled continuously or intermittently as desired. The upper transverse seal is the bottom seal of the next pouch to be formed and filled. The seal and cut may take place through flowable material. Impulse sealing is preferably employed in such a process, and sealing may occur through the flowable material.
[0020] The pouches manufactured using the film of the invention may range in size from generally 200 ml to 10 liters. The bags may range in size from 2 liters to over 300 gallons.
[0021] The major component of the film blend comprises about 70.5 wt % to about 98 wt % of one or more polymers selected from ethylene-alpha-olefin interpolymers and ethylene homopolymers, having a density between 0.915 g/cc and 0.935 g/cc and a melt index of less than 2 g/10 min. There are many examples of suitable polymers, which can be used as this component of the film blend. Suitable ethylene-alpha-olefin interpolymers can be polymerized using Zeigler-Natta catalysts. Companies such as Dow, Nova and Huntsman can produce suitable interpolymers commercially (tradenames Dowlex™ Sclair™ and Rexell™ respectively) using a solution phase process; ExxonMobil, ChevronPhillips and Nova can produce suitable interpolymers (tradenames NTX™, MarFlex™ LLDPE, Novapol™ LLDPE respectively) by a gas phase process; ChevronPhillips uses a slurry process (MarFlex™ LLDPE). Suitable ethylene-alpha-olefin interpolymers can also be polymerized using single site catalysts such as ExxonMobil's or ChevronPhillips' metallocene catalysts or Dow's constrained geometry catalysts (tradenames Exceed™, MarFlex mPACT™ and Elite™ respectively). Suitable low density ethylene homopolymers can be polymerized using the high pressure polymerization process. Commercial examples of such polymers are made by companies such as Nova, Dow, ExxonMobil, ChevronPhillips and Equistar. A Petrothene™ grade from Equistar is used in the present examples.
[0022] The minor component of the film blend comprises from about 2.0 to about 9.5 wt % of an ethylene C 4 -C 10 -alpha-olefin interpolymer having a density of less than 0.890 g/cc and a melt index of less than 5 g/10 min. This polymer is currently best produced in a single-site catalyst or metallocene catalyst polymerization process, but any other interpolymer may be selected for use that has similar characteristics suitable for the film to be produced, may be selected. Typical examples are ethylene-octene interpolymers marketed by Dow under the tradenames Engage™ and Affinity™, and by ExxonMobil under the tradename Exact™. ExxonMobil also manufactures suitable ethylene-hexene and ethylene-butene interpolymers, which are also marketed under the Exact™ tradename. Dow manufactures suitable ethylene-butene interpolymers under the tradename Flexomer™. Alternatives to any of these commercially available products would be selectable by a person skilled in the art for purposes of the invention.
[0023] The processing additives are generally referred to as “masterbatches” and comprise special formulations that can be obtained commercially for various processing purposes. In the present instance, the processing additives are selected from combinations of slip agents, anti-block agents, colorants and processing aids. In the present formulation, the amount of processing additives may range from 0 wt % to about 20 wt %. Typical masterbatches may comprise 1-5 weight % erucamide slip agent, 10-50 weight % silica anti-block, 1-5 weight % fluoropolymer process aid, and combinations of two and of three of these additives.
[0024] The sealant film of this invention may be used on its own as a monofilm for making bags and pouches. The monofilm produced may have a film thickness of from about 20 to about 125 microns. Preferably, the monofilm thickness may range from about 40 to about 80 microns. Alternatively, the monofilm may be incorporated into a multi-ply bag structure, where it functions as the sealant layer. Multi-layer films may be produced using the sealant film, generally having thicknesses in the range of from about 40 to about 150 um, or from about 40 to about 80 microns.
[0025] The films of the invention may be produced by any suitable method for producing polyethylene film. The monofilm can be made by a blown film process, but may also be made by a cast film process. Multi-layer films can be blown or cast extrusions, thermal laminates or adhesive laminates.
[0026] The adhesive used in the adhesive laminates may be an extruded adhesive, a solvent-based adhesive, a 100% solids adhesive or a water-based adhesive. Examples include the broad line of BYNEL™ coextrudable adhesives marketed by E.I. du Pont de Nemours. Non-polymeric materials can be included in the multi-layer and multi-ply film structures as layers such as, for example aluminum, aluminum oxide or silicon oxide.
[0027] Monolayer films are normally used for making pouches, which require moisture barrier but not high oxygen barrier. The inner plies of multi-ply bags, which are added to improve shipping and handling performance, are normally monofilms. Multi-layer films are used to make pouches or bags, which need a more sophisticated combination of properties, for example, higher barrier to oxygen. The outer ply of a multi-ply bag is often a multi-layer film. The middle ply may also be a multi-layer film, and is often of different composition than the outer ply. The sealant film of the invention may therefore be used as a single ply in such a structure or as part of a multi-layer film structure as described above.
[0028] In multi-layer polymeric film, the layers generally adhere to each other over the entire contact surface, either because the polymer layers inherently stick to each other or because an intermediate layer of a suitable adhesive is used. The layers in a multi-ply bag do not adhere to each other except at the edges of the bag in the heat seals.
[0029] Finally in another main aspect, the invention provides a multi-ply bag, used for packaging flowable material, which has an outer multi-layer film ply that has an inner sealant layer, an outer layer, or both layers are the monofilm as described above having a thickness of from about 2 to about 50 μm.
[0030] The filled pouches produced herein are manufactured in accordance with known packaging techniques. Usually they are made using vertical or horizontal form, fill and seal processes which are referred to by the acronyms VFFS and HFFS, respectively. The bags are pre-made and then usually filled through a fitment. They are often radiation sterilized in a batch process by the bag manufacturer. The packaging conditions may include those for aseptic packaging.
[0031] There is extensive description in the art of the types of polymers, interpolymers, copolymers, terpolymers, etc. that may be used in the film structures of the present invention. Examples of patents that describe such polymers include U.S. Pat. Nos. 4,503,102; 4,521,437; and 5,288,531. These patents describe films used to make pouches, which films may also be used to make bags. Other patents include CA 2,182,524 and CA 2,151,589. These patents describe pouch making using vertical form, fill and seal machines and processes. The disclosures of all of these patents are incorporated herein by reference.
[0032] The capacity of the pouches of the present invention may vary. Generally, the pouches may contain from about 20 milliliters to about 10 liters, preferably from about 10 milliliters to about 8 liters, and more preferably from about 1 liter to about 5 liters of flowable material.
[0033] The pouches of the present invention can also be printed by using techniques known in the art, e.g., use of corona treatment before printing.
[0034] A number of patents held by Dow in this area include CA 2,113,455; CA 2,165,340; CA 2,239,579; CA 2,231,449 and CA 2,280,910. All of these describe various polymer blends which are used to manufacture flexible packages such as those described herein. An example of a patent in this area is Exxon Mobil U.S. Pat. No. 5,206,075.
[0035] As will be understood by those skilled in the art, the multilayer film structure for the pouch of the present invention may contain various combinations of film layers as long as the sealant layer forms part of the ultimate film structure. The multilayer film structure for the pouch of the present invention may be a coextruded film, a coated film or a laminated film. The film structure also includes the sealant layer in combination with a barrier film such as polyester, nylon, EVOH, polyvinylidene dichloride (PVDC) such as SARAN™ (Trademark of The Dow Chemical Company), metallized films and thin metal foils. The end use for the pouch tends to dictate, in a large degree, the selection of the other material or materials used in combination with the seal layer film. The pouches described herein will refer to seal layers used at least on the inside of the pouch.
[0036] By flowable materials is meant materials which are flowable under gravity or which may be pumped. Normally such materials are not gaseous. Food products or ingredients in liquid, powder, paste, oils, granular or the like forms, of varying viscosity, are envisaged. Materials used in manufacturing and medicine are also considered to fall within such materials.
[0037] The VFFS and HFFS machines are well known in the art. The pouches are also well known. The film structure once made can be cut to a desired width for use on the machine. A pouch generally comprises a tubular shape having a longitudinal lap seal or fin seal with transverse end seal, such that, a “pillow-shaped” pouch is formed when the pouch is manufactured and contains flowable material.
BRIEF DESCRIPTION OF THE DRAWINGS
[0038] The following drawings are used to illustrate the invention and should not be used to construe the claims in a narrowing fashion.
[0039] FIG. 1 graphically depicts the number of Gelbo flex pinholes which develop in 300 cm 2 of film after 20,000 Gelbo flexes vs. the wt % ULDPE-minor component. Thus the figure illustrates Gelbo flex improvement (fewer pinholes) as a function of ULDPE concentration;
[0040] FIG. 2 graphically depicts a lowering of thermal resistance as a function of ULDPE concentration. The plot is of DSC peak melting point in (CC) values vs. wt % ULDPE-minor component values;
[0041] FIG. 3 graphically depicts representation of the loss of stiffness as a function of ULDPE concentration in a monofilm. The plot is MD tensile modulus (psi) vs. wt % ULDPE-minor component;
[0042] FIG. 4 is a graphical depiction showing that very low concentrations of extremely low density ULDPE's are more effective in improving the flex crack resistance of a LLDPE film than higher concentrations of a higher density ULDPE;
[0043] FIG. 5 graphically depicts a DSC melting curve for control film 1 ;
[0044] FIG. 6 graphically depicts a DSC melting curve for example film 1 . 9 A;
[0045] FIG. 7 graphically depicts a DSC melting curve for example film 1 . 9 B;
[0046] FIG. 8 graphically depicts a DSC melting curve for counter example film 1 . 30 C;
[0047] FIG. 9 is a bar graph representation illustrating improving the flex crack resistance of lower density polyethylene films vs. higher density films;
[0048] FIG. 10 illustrates a typical pillow-shaped pouch made using a film of the present invention; and
[0049] FIG. 11 illustrates a bag line flow diagram for making two-ply bags using the sealant film of the invention as a monolayer in such a bag structure.
DETAILED DESCRIPTION OF THE INVENTION
[0050] The following examples are used to illustrate the invention and should not be used to limit the scope of the claims. All parts and percentages are by weight unless otherwise specified.
Pouch Making
[0051] In FIG. 10 of the present invention there is illustrated a typical pouch generally designated at 1 , for containing liquids made using the film of the present invention. With regard to FIG. 10 , there is shown a pouch 1 being a tubular member 2 having a longitudinal lap seal 4 and transverse seals 3 such that, a “pillow-shaped” pouch is formed when the pouch is filled with flowable material.
[0052] The pouch manufactured according to the present invention is preferably the pouch 1 shown in FIG. 10 made on so-called vertical form, fill and seal (VFFS) machines well known in the art. Examples of commercially available VFFS machines include those manufactured by Inpaco or Prepac. A VFFS machine is described in the following reference: F. C. Lewis, “Form-Fill-Seal,” Packaging Encyclopedia, page 180, 1980, the disclosure of which is incorporated herein by reference.
[0053] In a vertical form, fill and seal (VFFS) packaging process, a sheet of the plastic film structure described herein is fed into a VFFS machine where the sheet is formed into a continuous tube in a tube-forming section. The tubular member is formed by sealing the longitudinal edges of the film together—either by lapping the plastic film and sealing the film using an inside/outside seal or by fin sealing the plastic film using an inside/inside seal. Next, a sealing bar seals the tube transversely at one end being the bottom of the “pouch”, and then the fill material, for example milk, is added to the “pouch.” The sealing bar then seals the top end of the pouch and either burns through the plastic film or cuts the film, thus, separating the formed completed pouch from the tube. The process of making a pouch with a VFFS machine is generally described in U.S. Pat. Nos. 4,503,102 and 4,521,437, the disclosures of which are both incorporated herein by reference.
Bag Making
[0054] Referring now to FIG. 11 , of the accompanying drawings, bag-making is exemplified by a line to make two-ply bags with a spout. Four rolls of film of the same width are mounted on unwind stands ( 1 ). The two outermost rolls form the outer ply of the bag. These rolls are normally identical in film composition. The outer plies are usually the most complicated film layers in the bag structures. They are often laminates or coextrusions with a core layer of a barrier polymer such as nylon, polyester, or EVOH. Thin non-polymeric layers may also be included such as aluminum, aluminum oxide or silicon oxide, usually as coatings on the core layer of the laminate. The laminated core layer material is also often monaxially or biaxially oriented.
[0055] The two innermost rolls form the inner ply of the bag. They are normally identical in composition, and are most often monofilms or coextrusions of polyethylene.
[0056] A time code is applied to the outer surface of one of the outer plies at station ( 2 ). A hole is punched through the outer and inner plies that will form one side of the bag at station ( 3 ). At station ( 4 ), a spout, the form of which is selected from any of the standard forms known in the bag making art, is inserted through the hole, and an enlarged flange of the spout is normally heat sealed to the inner and outer film plies. At station ( 5 ), a pair of heat seals is applied across the width of the films, forming the bottom seal of one bag and the top seal of the next bag. A brush or other means for removing air trapped between the film plies is shown at station ( 6 ). The seals parallel to the length of the bag line are applied at either side of the films at station ( 7 ). Rollers, which pull the films through the bag line, are located at position ( 8 ).
[0057] At station ( 9 ), a knife or hot sealing bar may be used to completely separate the bags between the adjacent cross seals. Alternately, a sealing bar may be used to form a perforation between adjacent bags, so that they can be wound or folded up as a continuous roll. Station ( 10 ) is a conveyor belt to push the bag, or strip of bags, to the end of the bag-making line. At the final station ( 11 ), the bags are packed into boxes. Many variations of this procedure are known and the person skilled in the art would select from those processes as necessary for the proposed application.
[0058] The following procedures and test methods were used to develop the information set forth in the subsequent examples.
Gelbo Flex
[0059] This test method is valuable in determining the resistance of flexible packaging materials and films to flex-formed pinhole failures. This test method does not measure any abrasion component relating to flex failure. Physical holes completely through the structure are the only failures measured by the coloured turpentine portion of this test.
[0060] The Gelbo Flex tester is set up to test in accordance with ASTM F392. This apparatus consists essentially of a 3.5″ (90 mm) diameter stationary mandrel and a 3.5″ movable mandrel spaced at a distance of 7″ (180 mm) apart from face-to-face at the start position (that is, maximum distance) of the stroke. The sides of the film sample are taped around the circular mandrels so that it forms a hollow cylinder between them. The motion of the moving mandrel is controlled by a grooved shaft to which it is attached. The shaft is designed to give a twisting motion of 440 degrees and, at the same time, move toward the fixed mandrel to crush the film so that the facing mandrels end up 1″ apart at minimum distance. The motion of the machine is reciprocal with a full cycle consisting of the forward and return stroke. The machine operates at 45 cycles per minute.
[0061] By means of this tester, specimens of flexible materials are flexed at standard atmospheric conditions (23° C. and 50% relative humidity), unless otherwise specified. The number of flexing cycles can be varied depending on the flex crack resistance of the film structure being tested. A pinhole resistant film will develop very few pinholes (less than 10) when flexed for a large number of cycles (20,000).
[0062] The flexing action produced by this machine consists of a twisting motion, thus, repeatedly twisting and crushing the film. Flex crack failure is determined by measuring pinholes formed in the film. These pinholes are determined by painting one side of the tested film sample with coloured turpentine and allowing it to stain through the holes onto a white backing paper or blotter. Pinhole formation is the standard criterion presented for measuring failure, but other tests such as gas-transmission rates can be used in place of, or in addition to, the pinhole test. Obviously if a pinhole exists in the film, an oxygen molecule can pass directly through it without ever entering, diffusing through, and exiting the polymeric layers. But even when a hole does not exist, the flexed film structure may be damaged to an extent that alters its permeability to oxygen and other gases.
DSC (ASTM E794/E793)
[0063] Differential Scanning calorimetry (DSC) determines the temperature and heat flow associated with material transitions as a function of time and temperature. The DSC cell is purged with nitrogen gas at a flow rate of 50 ml/minute. Heating and cooling rates are 10° C./min. For polyethylene film samples, the test starts at −50° C. and goes as high as 200° C. Each sample is melted, solidified and remelted. The test method allows for an initial equilibration at −50° C., and the temperature equivalent of five minutes of flat baseline prior to transitioning from heating to cooling, and vice versa. Data is analyzed with the measuring instruments' software. The first heating, cooling, and second heating cycles are plotted separately. The peak melting point values reported in the Tables come from the second heating cycle.
Tensile Modulus
[0064] Tensile Modulus of the polyethylene films is measured in accordance with ASTM Method D882, with two exceptions: a dumbbell specimen shape is used as defined in ASTM D638 and a crosshead speed of 500 mm/min is used, rather than 5 mm/min. The adjusted method correlates very well with the exact ASTM Method, which calls for a straight test sample and the slower crosshead speed. The values reported in the tables are the Tensile Modulus measured in the machine direction of the film.
[0065] The following Table 1 describes the resins used in the examples.
[0000]
TABLE 1
RESINS USED IN THE EXAMPLES
Melt Index
(g/10
minutes
@ 2.12 kg,
Density
Supplier
Grade
Description
190° C.)
(g/cc)
Dow
Elite ™ 5100G
ethylene-octene
0.85
0.920
LLDPE
(LLDPE-1)
Dow
Elite ™ 5110G
ethylene-octene
0.85
0.926
LLDPE
(LLDPE-2)
Equistar
Petrothene
ethylene
1.00
0.920
NA960-000
homopolymer
(HP-LDPE-1)
Dow
LD132I
ethylene
0.22
0.921
homopolymer
(HP-LDPE-2)
Chevron
mPACT ™ D449
ethylene
0.8
0.942
Phillips
homopolymer
MDPE
Nova
Sclair ™ 19C
ethylene
0.95
0.958
homopolymer
HDPE
Dow
Affinity ™ PL1880
ethylene-octene
1.0
0.902
ULDPE
(ULDPE-C)
Dow
Engage ™ 8200
ethylene-octene
5.0
0.870
ULDPE
(ULDPE-A)
Dow
Engage ™ 8180
ethylene-octene
0.5
0.863
ULDPE
(ULDPE-B)
Method for Blending Control Film Formulations and Making Films
[0066] Control film blends were made by blending the major resin component with 3.8 weight percent of additive masterbatches, so that the final film contained approximately 500 ppm erucamide slip agent, 2000 ppm silica antiblock and 600-850 ppm fluoropolymer process aid. The blends were blown into 51 μm thick monofilms on an extrusion line with a 150 mm diameter die at a blow-up ratio of 2.33:1 and throughput rate of about 47 kg/hour (0.10 kg/mm of die diameter).
[0000]
TABLE 2
CONTROL FILMS
Control Film Number
Major Resin Component
Control Film 1
Elite ™ 5100G
Control Film 2
Elite ™ 5110G
Control Film 3
Petrothene ™ NA960-000
Control Film 4
Dow LD132I
Control Film 5
mPACT ™ D449C
Control Film 6
Sclair ™ 19C
Method for Blending Film Formulations and Making Films of the Invention
[0067] Films to exemplify the invention were made by blending the same major component resins with minor amounts of ULDPE resins, which satisfy the extremely low density criterion. The same 3.8 weight percent of extrusion aid master batches was added to each blend, and the 51 μm thick films were blown on the same extrusion line as the control films under the same conditions.
[0000]
TABLE 3
EXAMPLE FILMS
Example Film Number
Major Component
Minor Component
Example Film 1.3A
Elite ™ 5100G
3 wt % Engage ™ 8200
Example Film 1.6A
Elite ™ 5100G
6 wt % Engage ™ 8200
Example Film 1.9A
Elite ™ 5100G
9 wt % Engage ™ 8200
Example Film 1.9B
Elite ™ 5100G
9 wt % Engage ™ 8180
Example Film 2.1A
Elite ™ 5110G
1 wt % Engage ™ 8200
Example Film 2.3A
Elite ™ 5110G
3 wt % Engage ™ 8200
Example Film 2.6A
Elite ™ 5110G
6 wt % Engage ™ 8200
Example Film 2.9A
Elite ™ 5110G
9 wt % Engage ™ 8200
Example Film 3.9A
Petrothene ™
9 wt % Engage ™ 8200
NA960-000
Example Film 4.9A
Dow LD132I
9 wt % Engage ™ 8200
Counter Example Films
[0068] A counter example was made by blending Elite™ 5100G with a higher amount of Affinity™ PL1880, and 3.8 weight percent of extrusion aid masterbatches. Film was blown at a thickness of 51 μm on the same extrusion line as the control films under the same conditions. This blend is not one of the invention because the concentration of the ULDPE component is too high and the density of Affinity™ PL1880 (ULDPE-C) is too high.
[0069] Additional counter example films were also made by blending 9 weight percent Engage™ 8200 (ULDPE-A) and 3.8 weight percent of extrusion aid masterbatches into ChevronPhillips mPACTT™ D449, and into Nova Sclair™ 19 C. These blends are not of the invention because the major polyethylene component is too high in the density.
[0000]
TABLE 4
COUNTER EXAMPLE FILMS
Counter Example Film Number
Major Component
Minor Component
Counter Example Film 1.30C
Elite ™ 5100G
30 wt % Affinity ™
PL1880
Counter Example Film 5.9A
mPACT ™ D449
9 wt % Engage ™
8200
Counter Example Film 6.9A
Sclair ™ 19C
9 wt % Engage ™
8200
Example 1
[0070] The overall test results for the Control films are compared with those of the example films containing 9 weight % of a suitable extremely low density ULDPE resin. It can be seen in Table 5 that the example films consistently improved the pinhole resistance of a polyethylene film, while maintaining temperature resistance and stiffness.
[0000]
TABLE 5
OVERALL SUMMARY OF RESULTS
DSC
Machine
Peak
Direction
Average Number of
Melting
Tensile
Gelbo Flex Pinholes
Point
Modulus
Sample
(10,0000 c)
(15,000 c)
(20,000 c)
(° C.)
(psi)
Control Film 1
11.5
15.5
15
122.02
29737
Example Film 1.9A
5.0
5.5
5
121.42
23582
Example Film 1.9B
3.5
3.5
7.8
121.35
23261
Counter Example Film 1.30D
6.5
9.5
15
120.40
22401
Control Film 2
45
33
123.42
36679
Example Film 2.9A
25
18
122.36
27964
Control Film 3
45
109.13
23722
Example Film 3.9A
30
108.76
21588
Control Film 4
34
108.56
26646
Example Film 4.9A
12.5
108.84
22304
Control Film 5
50.5
130.80
83851
Counter Example Film 5.9A
44.5
130.04
61571
Control Film 6
70.5
134.55
95855
Counter Example Film 6.9A
61.5
134.21
78064
Example 2
[0071] These results indicate that the addition of less than 2 weight % of the extremely low density ULDPE component of the invention is ineffective in improving the flex crack resistance of the low density polyethylene film. Adding more than 9.5 wt % of the extremely low density ULDPE component has a significant deleterious effect on both the thermal resistance and stiffness of the low density polyethylene film. In addition, it becomes difficult to incorporate larger amounts of such an extremely low melting polymer into low density polyethylenes, of density 0.915-0.935 g/cc, using normal manufacturing equipment without experiencing premature melting of the pellets, which can result in extruder feedthroat bridging and other temperature-related problems.
[0072] Table 6 and FIGS. 1 to 3 will be used to illustrate how the novel blending technique can be used to select the concentration of the extremely low density ULDPE component to measurably improve flex crack performance of a low density polyethylene film, while at the same time minimizing the negative effect on thermal resistance and stiffness. Consider a film made from LLDPE-1 (Elite™ 5100G). FIG. 1 shows that, on average, this film develops 15 pinholes/300 cm 2 after 20,000 cycles of Gelbo Flex testing. Addition of 6 weight % of ULDPE-A to the film recipe results in a film, which develops, on average, only 10 pinholes/300 cm 2 after 20,000 cycles. Referring to FIG. 2 , it can be seen that the DSC peak melting point has dropped by less than half a degree Celscius. Thermal resistance is, therefore, well maintained. FIG. 3 shows that the machine direction Tensile Modulus of the film has decreased from 30,000 psi to 25,000 psi. However, a film with this stiffness should have good runnability on pouch and bag-making equipment.
[0073] Addition of 9 weight % ULDPE-A to the LLDPE-1 film recipe results in a film with even more impressive Flex crack resistance. Only 5 pinholes/300 cm 2 develop, on average, after 20,000 test cycles. Referring to FIGS. 2 and 3 respectively, it can be seen that DSC peak melting point drops by just over half a degree Celsius and that machine direction Tensile Modulus drops to about 23,000 psi. The negative impact on thermal resistance and stiffness is larger, but probably acceptable in most bag and pouch applications.
[0074] Film made from LLDPE-2 (Elite™ 5110G) has inferior pinhole resistance to film made from LLDPE-1. It develops, on average, 33 pinholes/300 cm 2 after 20,000 Gelbo Flex cycles ( FIG. 1 ). Addition of only 3 weight % of ULDPE-A to the LLDPE-2 film recipe results in a film which develops, on average, only 28 pinholes/300 cm 2 after 20,000 test cycles ( FIG. 1 ). This is a Flex Crack improvement of 15%. Referring to FIGS. 2 and 3 , it can be seen that DSC peak melting point is unaffected by this recipe change and machine direction Tensile Modulus drops from 38,000 psi to 35,000 psi.
[0075] A larger addition of 6 weight % ULDPE-A to the same recipe improves Flex Crack resistance to, on average, 22 pinholes/300 cm 2 after 20,000 cycles, an improvement of 30%. Referring to FIGS. 2 and 3 , it can be seen that DSC peak melting point is still unaffected by this recipe change and machine direction Tensile Modulus drops from 38,000 psi to 31,000 psi.
[0076] An even larger addition of 9 weight % ULDPE-A to the same recipe improves Flex Crack resistance, on average, to 18 pinholes/300 cm 2 after 20,000 cycles, an improvement of 45%. Referring to FIGS. 2 and 3 , it can be seen that DSC peak melting point has dropped by about 1° C. and machine direction Tensile Modulus from 38,000 psi to 28,000 psi.
[0077] These blended films all have superior shipping and handling characteristics, as measured by Gelbo Flex performance, than the composed of LLDPE-2 alone. At the same time, they can be tailored to retain as much thermal resistance and stiffness as is required by the end-use.
[0000]
TABLE 6
RESULTS FOR FILMS WHICH ARE BLENDS OF ULDPE-A
WITH EITHER LLDPE-1 OR LLDPE-2
Machine
Average
DSC Peak
Direction
Number of
Melting
Tensile
wt %
Pinholes
Point
Modulus
Sample
ULDPE-A
(20,000 cycles)
(° C.)
(psi)
Control Film 1
0
15
122.02
29,737
Example Film 1.3A
3
15
122.01
27,758
Example Film 1.6A
6
10
121.55
25,316
Example Film 1.9A
9
5
121.42
23,582
Control Film 2
0
33
123.42
36,679
Example Film 2.1A
1
32
123.39
39,096
Example Film 2.3A
3
28
123.47
35,377
Example Film 2.6A
6
22
123.54
30,324
Example Film 2.9A
9
18
122.36
27,964
Example 3
[0078] This Example illustrates how the novel approach of the present invention of blending a minimal amount of ULDPE, which satisfies the extremely low density criterion, into a LLDPE improves flex crack resistance more effectively than the conventional approach of blending a larger amount of a higher density ULDPE into the same LLDPE. Comparison of Example Films 1 . 9 A and 1 . 9 B to Counter Example Film 1 . 30 C in Table 5, shows that both example films result in measurably fewer Gelbo flex pinholes than the counter example film, when flexed for 10,000, 15,000 or 20,000 cycles.
[0079] FIG. 4 is a visual depiction showing that very low concentrations of extremely low density ULDPEs are more effective in improving the flex crack resistance of a LLDPE film than higher concentrations of a higher density ULDPE.
[0080] The better flex crack resistance of films of the invention cannot simply be a molecular weight effect because ULDPE-A of the invention, Engage™ 8200, is actually higher in Melt Index, or lower in average molecular weight, than Affinity™ PL1880, the ULDPE-C of the Counter Example Film 1 . 30 C.
[0081] Table 1 shows that blends of the invention also maintain thermal resistance and stiffness better than prior art ULDPE blends.
[0082] FIG. 5 is the DSC Melting curve for Control Film 1 , made from Elite™ 5100G. The graph shows a melting peak at 122.02° C., and a shoulder to the lower temperature side. The shoulder indicates that a measurable portion of the Elite™ 5100G polymer melts at temperatures below 122° C.
[0083] FIG. 6 is the DSC melting curve for Example Film 1 . 9 A. It looks very much like that of Control Film 1 in FIG. 5 . The peak melting point is 121.42° C., and the shoulder to the lower temperature side looks unchanged. Referring to FIG. 7 , which is the DSC Melting Curve for Example Film 1 . 9 B, it can be seen that the DSC curve for Example Film 1 . 9 B also looks very similar to FIG. 5 , with a melting peak of 121.35° C.
[0084] In FIG. 8 , it can be seen that the DSC Melting Curve for Counter Example Film 1 . 30 C. By contrast, the DSC melting curve for Counter Example 1, 30D looks somewhat different. The melting peak is a degree lower at 120.40° C., and the shoulder to the lower temperature side of the curve has grown considerably. This film will have lower thermal resistance than the other three.
Example 4
[0085] The inventive blending technique is not as effective for improving the flex crack resistance of medium density to high density polyethylenes. This can be observed in the data of Table 5, and is shown visually in FIG. 9 . The number of pinholes/300 cm 2 in a low density polyethylene film can be cut in half, whereas the number of pinholes in a medium to high density film is reduced by less than 15%.
[0086] The invention may be varied in any number of ways as would be apparent to a person skilled in the art and all obvious equivalents and the like are meant to fall within the scope of this description and claims. The description is meant to serve as a guide to interpret the claims and not to limit them unnecessarily. | A sealant film for use in a film structure for the manufacture of pouches and bags for containing flowable materials, the sealant film comprising: ( 1 ) from about 2.0 to about 9.5 wt %, based on 100 wt % total composition, of an ethylene C 4 -C 10 -alpha-olefin interpolymer having a density of from 0.850 to 0.890 g/cc and a melt index of 0.3 to 5 g/10 min, the interpolymer being present in an amount that optimizes flex crack resistance as measured using a Gelbo Flex tester set up to test in accordance with ASTM F392, and minimizes reduction of thermal resistance, as measured using DSC (ASTM E794/E793) Differential Scanning calorimetry (DSC) which determines temperature and heat flow associated with material transitions as a function of time and temperature, and stiffness of the sealant film layer as measured using Tensile Modulus of the polyethylene films measured in accordance with ASTM Method D882; ( 2 ) from about 70.5 wt % to about 98.0 wt %, based on 100 wt % total composition, of one or more polymers selected from ethylene homopolymers and ethylene C 4 -C 10 -alpha-olefin interpolymers, having a density between 0.915 g/cc and 0.935 g/cc and a melt index of 0.2 to 2 g/10 min; and ( 3 ) from about 0 wt ° A) to about 20.0 wt %, based on 100 wt % total composition, of processing additives selected from slip agents, antiblock agents, colorants and processing aids; and wherein the sealant film has a thickness of from about 2 to about 60 μm. | 8 |
BACKGROUND OF THE INVENTION
This invention relates generally to means for aiming a cue ball with respect to an object ball when practicing the game of billiards.
The game of billiards had its origin in Europe over 400 years ago. Today, the game of billiards has emerged into an exhaustive number of forms played throughout the world. There exist amateurs and professionals alike who spend countless numbers of hours mastering the skill required to become the best players of the game.
Pocket billiards, commonly called pool, has a large number of players, particularly amateurs, in the United States. A white cue ball and fifteen colored object balls are used, with the balls numbered from 1 to 8 being solid colors and the balls numbered 9 to 15 being striped. The fundamental object of pocket billiards is to stroke the cue ball with a cue stick such that the cue ball strikes the object ball at the appropriate point to pocket the object ball.
To master the game of billiards, it is necessary for a player to develop the skill of stroking the cue ball so that the cue ball strikes the object ball at the proper point of contact to project the object ball into a pocket. The cue ball aiming device of the present invention may aid a player in developing such skill.
By positioning the cue ball aiming device of the present invention over the object ball and aligning the cue ball aiming device with the appropriate pocket, a player is able to eye the path the cue ball must follow to properly strike the object ball. When the cue ball is aimed at the cue ball aiming device and stroked accordingly, the cue ball will strike the object ball at the proper point of contact and project the object ball into the appropriate pocket.
SUMMARY OF THE INVENTION
By means of the present invention, a cue ball aiming device is provided to aid in practicing the game of billiards. The cue ball aiming device of the present invention provides a means to improve one's skill in playing the game of billiards. To accomplish this, the cue ball aiming device comprises a cue ball spotter, an object ball cradle, a center-to-center sight, and a support structure, all of which may be integrally formed.
The cue ball aiming device is placed on the surface of a billiard table such that the object ball cradle abuts against a portion of an object ball. The cue ball aiming device is oriented around the object ball so that the center-to-center sight is aimed at the appropriate pocket. By shooting the cue ball directly under the cue ball spotter, the cue ball will make contact with the object ball at the exact point to cause the object ball to be projected into the appropriate pocket.
By using the present invention, one's skill at the game of billiards may be greatly improved. An exemplary embodiment of the present invention is shown in the appended drawings and described in the detailed description of the preferred embodiment.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an isometric view of the preferred embodiment of the cue ball aiming device of the present invention. It depicts the cue ball aiming device in place as it appears just as the cue ball comes in contact with the object ball.
FIG. 2 is an isometric view of the preferred embodiment of the object ball cradle of the present invention.
FIG. 3 is a plan view of the preferred embodiment of the cue ball aiming device of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1, the preferred embodiment of a cue ball aiming device 10 of the present invention is shown. The cue ball aiming device 10 comprises a cue ball spotter 12, an object ball cradle 14, a center-to-center sight 16, and a support structure 18 and is adapted to rest on the playing surface of a billiard table (not shown).
In the preferred embodiment, the support structure 18 comprises a substantially horizontally-positioned member 20 and two substantially vertical appendages 22, all of which may form an integral piece.
The cue ball spotter 12 and object ball cradle 14 are affixed to the horizontally-positioned member 20 which, at one end thereof, forms the center-to-center sight 16. Although the preferred embodiment of the present invention depicts the cue ball spotter 12, the object ball cradle 14, and the center-to-center sight 16 as three separate components, all three components may be formed as one continuous structure, within the contemplation of the present invention. In fact, in order to mass produce the cue ball aiming device, the entire device may be injection-molded as an integral piece.
The horizontally-positioned member 20 is supported by the two vertical appendages 22. The base of each vertical appendage 22, at the outside surface thereof, is connected to a foot 24. The appendage 22 and the foot 24 may form an integral piece. The feet 24 provide stability for the cue ball aiming device 10 and prevent it from tipping over. The substantially horizontally-positioned member 20 may be supported by any configuration of substantially vertical appendages, including four legs, and any such configuration is within the contemplation of the present invention.
Having described the major components of the cue ball aiming device 10 of the present invention, the important features of the cue ball spotter 12, the object ball cradle 14, and the center-to-center sight 16 are discussed.
In the preferred embodiment, the cue ball spotter 12 comprises a circular disc having a diameter substantially equal to that of a billiard ball. For example, the cue ball spotter 10 may have a diameter substantially equal to 21/4". The circular disc may have any thickness, such as 1/4", as long as the distance between the bottom of the disc and the surface that the aiming device rests on is greater than the diameter of a ball, so that the cue ball may pass beneath the cue ball spotter.
Since the purpose of the cue ball spotter 12 is to provide a means for aiming a cue ball 30, any means which will accomplish this purpose may be provided and is within the contemplation of the present invention. For example, the cue ball spotter may comprise, but is not limited to, an elongated vertical cylinder, a replica of a cue ball, or a sight post such as that used on the end of a rifle.
One critical requirement of the cue ball spotter 12 is that the distance A between the centerline of the cue ball spotter 12 and the centerline of an object ball 32 when it is positioned against the object ball cradle 14 is substantially equal to the diameter of a ball, such as 21/4".
The object ball 32 is shown in FIG. 1 abutted against the object ball cradle 14. An isometric view of the object ball cradle is shown in FIG. 2. The object ball cradle of the preferred embodiment has a generally tubular shape with an outside diameter G less than the diameter of the object ball 32. It is assumed for purposes of the present invention that the diameter of the object ball 32 and the diameter of the cue ball 30 are equal to 21/4".
The object ball cradle 14 serves the important function of providing a means whereby the cue ball aiming device 10 may be properly positioned. The object ball cradle 14 is also designed so as not to obstruct the path of the object ball 32 as it is projected out from under the support structure 18.
The most critical feature of the object ball cradle 14 in the preferred embodiment is its height F (FIG. 2). The height F is dependent upon the thickness of the horizontally-positioned member 20, the outside diameter G of the object ball cradle 14, and the diameter of the object ball 32. By positioning the cue ball aiming device 10 over the object ball 32 so that the centerline of the object ball cradle 14 of the preferred embodiment and the centerline of the object ball 32 coincide, the height F of the object ball cradle 14 is determined so that the bottom of the object ball cradle 14 abuts against the object ball 32.
If the horizontally-positioned member 20 has a thickness of substantially 3/16", the cue ball aiming device 10 has a height B (FIG. 1) of substantially 31/8", and the object ball cradle 14 has an outside diameter G of substantially 1-11/16" and an inside diameter H of substantially 1-19/32", the height F of the object ball cradle 14 will be substantially 15/16". As shown in FIG. 2, only a portion of the circumference of the object ball cradle 14 has a height F. In other words, a portion of the circumference of the object ball cradle 14 has a height equal to F minus K. The dimension K, such as 1/4", is determined to that the object ball cradle 14 does not obstruct the path of the object ball 32 as it is projected out from under the support structure 18.
To further prevent obstruction of the path of the object ball 32, the object ball cradle 14 has a height F minus K extending more than 180 degrees around its circumference. In the preferred embodiment, the dimension J is determined to be greater than 1/4".
Although the object ball cradle 14 of the preferred embodiment of the present invention has the characteristics described above, any means which would enable the proper positioning of the cue ball aiming device 10 over the object ball 32 is within the contemplation of the present invention. For example, the object ball cradle may comprise, but is not limited to, one or more substantially conical-shaped nodules extending out from the inside surface of each vertical appendage 22 to enable the proper positioning of the cue ball aiming device without obstructing the path of the object ball as it is projected out from under the support structure.
The center-to-center sight 16 (FIG. 1) forms one end of the horizontally-positioned member 20 and preferably has an arrowhead shape. The center-to-center sight serves the important function of providing a means whereby the cue ball aiming device 10 may be properly aligned along the appropriate path for the object ball 32 to follow.
The center-to-center sight 16 of the preferred embodiment is designed so that an imaginary line extending horizontally from the point of the arrowhead will intersect both of the imaginary centerlines extending vertically upward through the center of the object ball when it is properly positioned under the aiming device and the cue ball spotter 12. The size and shape of the center-to-center sight 16 is not significant, and any modification which would provide a means for aligning the cue ball locator 10 is within the contempation of the present invention. For example, the center-to-center sight may comprise, but is not limited to, a sight post such as that used on the end of a rifle.
A substantially cylindrical-shaped pin 34 (FIG. 1) extending vertically upward from the horizontally-positioned member 20 may be positioned anywhere along the aforementioned imaginary line extending horizontally from the point of the center-to-center sight 16 to aid in aligning the cue ball aiming device. In the preferred embodiment shown in FIG. 1, the pin 34 is positioned at the centerline of the cue ball spotter 12. Such positioning serves two functions: (1) the pin 34, as stated above, aids in properly aligning the cue ball aiming device; and (2) the pin 34 provides additional means for aiming the cue ball at the cue ball spotter 12. Although the pin 34 of the preferred embodiment has the characteristics described above, any means which would aid in properly aligning the cue ball aiming device is within the contemplation of the present invention. For example, the pin 34 may take the form of, but is not limited to, a substantially rectangular-shaped member forming a V-notch at its top.
As is shown in FIG. 1, the cue ball aiming device 10 has a height B greater than the diameter of a billiard ball. The distance of the height B is dependent upon the thickness of the material used and the diameter of a ball. In the preferred embodiment, the height B may typically be 31/8".
Referring to FIG. 3, a plan view of the preferred embodiment of the cue ball aiming device 10 is shown. As is readily apparent, the distance between the inside surfaces of the feet 24 at the end of the cue ball aiming device 10 nearer the cue ball spotter 12 is greater than the diameter of the ball. As is also apparent, the distance between the inside surfaces of the feet 24 at the end of the cue ball aiming device 10 nearer the center-to-center sight 16 is greater than the distance between the inside surfaces of the feet 24 at the opposite end of the cue ball aiming device 10. In other words, the width of the horizontally-positioned member 20 gradually increases from rear (the end nearer the cue ball spotter 12) to front (the end nearer the center-to-center sight 16.)
As mentioned above, the only critical dimension shown in FIG. 3 is the distance A, which must be substantially equal to the diameter of a billiard ball. In the preferred embodiment, distance C may typically be 4"; distance D, 65/8"; and distance E, 21/4".
The above discussion has been predicated on the fact that billiard balls have a diameter of 21/4". It is within the contemplation of the present invention to provide a cue ball aiming device to accommodate any size of billiard balls.
Furthermore, it is to be understood that the invention will admit of other embodiments. The description of the preferred embodiment is given only to facilitate understanding of the invention by those skilled in the art and may not be construed as limiting the invention itself which is defined by the appended claims. | A cue ball aiming device, comprising a cue ball spotter, an object ball cradle, a center-to-center sight, and a support structure, is provided for aiming a cue ball with respect to an object ball. The cue ball aiming device may aid in improving one's skill in playing the game of billiards. | 0 |
BACKGROUND OF THE INVENTION
1. Field of Invention
This invention generally relates to a transportable storage container. More particularly, the present invention allows a single person to easily store and transport tools and equipment and to easily move the storage container throughout a job-site.
2. Description of the Related Art
Most construction workers are intimately familiar with “gang boxes.” Gang boxes are storage containers that, typically, are durable, secure, and heavy—particularly when loaded. Typically, each trade, or even foreman, at a construction project will have a gang box that is used to store tools, consumable materials, project drawings and plans, and other items that are required to be secured and safeguarded during the period that the gang box remains on the job-site while the gang box's owner is away from the job-site. For example, U.S. Pat. No. 3,838,586 to Tennison discloses an electrician's gang box that includes box structure which renders the box inaccessible to malefactors for the purpose of destroying the padlock.
However, a significant disadvantage of gang boxes like the one disclosed in the Tennison patent is that such boxes are heavy and difficult to transport. For example, a typical gang box is constructed of metal and is between 5 and 6 feet long, 3 feet wide and 3 to 4 feet tall. The gang box is then typically filled with tools and equipment that can easily weigh hundreds of pounds. To move a gang box from one job-site to another, or, to or from a construction company's office, requires the following process: 1) the gang box is unloaded of tools and equipment; 2) the box is physically lifted by three to four persons into the back of an appropriate vehicle; and 3) the tools and equipment are reloaded into the gang box. Upon arrival at the new destination, this process must be reversed. Obviously, this process is time and labor intensive.
Additionally, once on a jobsite, moving a typical gang box between locations at the jobsite, or to different floors of a building, involves a similar process of unloading the gang box, moving the gang box, and then reloading the gang box. Moreover, on many jobsites it is not possible to move gang boxes around the job site because typical gang boxes are too wide to fit through many standard door openings.
Given these inefficiencies, there is a need for a more efficient system that is of simple design and construction, that is inexpensive to manufacture, and that allows for the secure storage of tools and other valuables on the job site while providing a storage device that is easily transported, manageable by one person, and able to easily move to different locations on a job site.
BRIEF DESCRIPTION OF THE DRAWINGS
There are presently shown in the drawing embodiments of which are presently preferred, it being understood, however, that the invention is not so limited to the precise arrangements and instrumentalities shown, wherein:
FIG. 1 is an isometric view of the transportable storage container of the present invention;
FIG. 2 is a side view of the transportable storage container of the present invention; and
FIG. 3 is a bottom view of the transportable storage container of the present invention.
The below table summarizes the reference numbers and associated elements shown in the above drawings:
100
storage container
101
top
102
frame extension
103
front wall
104
side wall
105
rear wall
106
hinge
107
pin
108
coupler
109
bottom
201
suspension
202A
first wheel well
202B
second wheel well
203
lock pocket
204A
first castor
204B
second castor
205
castor leg
206
castor leg receiver
207
lock tab
208
wheel system
209
shackle
210
castor assembly
300
frame
301A
first wheel
301B
second wheel
302A
first longitudinal member
302B
second longitudinal member
303
second transverse member
304
first transverse member
305
axle
306
third longitudinal member
DETAILED DESCRIPTION OF THE INVENTION
A first embodiment of a transportable storage container 100 is shown in a side perspective view in FIG. 1 . The transportable storage container 100 includes a front wall 103 , a rear wall 105 , two side walls 104 , and a top 101 . It also includes a bottom 109 which is not shown in this view. Top 101 is shown in a partially open position and is hingedly connected to rear wall 105 via hinge 106 . Hinge 106 may include any appropriate means for allowing top 101 to move from a closed position, where lock tabs 207 are inserted into lock pockets 203 , to an open position, where full access to the interior of transportable storage container 100 is allowed. Such means may include a single strap or piano hinge, or multiple hinges as shown in FIG. 1 . In the closed position, lock tabs 207 are engaged into lock pockets 203 such that a padlock, or other locking device (not shown), may secure top 101 to front wall 103 in such a manner that the locking device is protected from bolt cutters, thus enhancing the security of the transportable storage container 100 .
Front wall 103 , rear wall 105 , side walls 104 , top 101 , and bottom 109 may be constructed of any durable, strong, sturdy, material. In one embodiment, these components are constructed of 10 gauge sheet metal. A sufficiently rigid and dense plastic material could also be used for these components.
FIG. 3 is a bottom view of frame 300 that supports transportable storage container 100 . In this embodiment, frame 300 is composed of two longitudinal members 302 , a first transverse member 304 , and a second transverse member 303 . Longitudinal members 302 are connected to first transverse member 304 and second transverse member 303 by welding or by a mechanical connection such as screws, nails, nuts and bolts, or rivets. Transportable storage container 100 is attached to frame 300 by any suitable means such as welding, or by the use of mechanical connections such as screws, nails, nuts and bolts, or rivets. In the embodiment shown, transportable storage container 100 is welded to frame 300 , and frame 300 is itself a welded assembly; also, longitudinal members 302 are constructed of tube steel and first transverse member 304 and second transverse member 303 are constructed of angle iron.
As used herein, the term “perimeter” refers to the outside edges of the area defined by the length and width of transportable storage container 100 . Third longitudinal member 306 is connected to first transverse member 304 intermediate to the connections of longitudinal members 302 to first transverse member 304 . Third longitudinal member 306 may also be constructed of tube steel. Frame 300 is constructed such that first longitudinal members 302 A is disposed sufficiently inward along first transverse member 304 and second transverse member 303 that first wheel 301 A is recessed within the perimeter created by portable storage container 100 . Similarly, Frame 300 is constructed such that second longitudinal members 302 B is disposed sufficiently inward along first transverse member 304 and second transverse member 303 that second wheel 301 B is recessed within the perimeter created by portable storage container 100 . First castor 204 A and second castor 204 B are similarly located within the perimeter created by portable storage container 100 . Thus, the effective rolling width of transportable storage container 100 is defined by its perimeter as no components extend beyond the width of transportable storage container 100 .
Referring to FIG. 2 , wheel system 208 can be seen. Wheel system 208 is comprised of wheel 301 and suspension 201 . In this embodiment, wheel 301 is a standard boat trailer wheel and suspension 201 is a single leaf spring. Shackles 209 are attached to frame 300 . Suspension 201 is connected to shackles 209 . As is known to those skilled in the art, alternative suspension systems may be employed such as coil spring systems. Alternatively, the suspension system may be omitted; however, omitting suspension 201 will result in decreased ride quality and shock absorption when transportable storage container 100 is being towed by a vehicle.
As shown in FIG. 3 , first wheel 301 A is connected to second wheel 301 B by axle 305 . In this embodiment, axle 305 is constructed of tube steel, but may also be constructed from any suitable structural material such as metal pipe, wood, or a composite material. Axle 305 is connected to suspension 201 at wheels 301 A and 301 B.
Referring back to FIG. 1 , frame extension 102 can be seen connected to frame 300 . In this embodiment, frame extension 102 is constructed of tube steel of a size that allows a slip fit connection between frame extension 102 and first longitudinal member 302 A, second longitudinal member 302 B, and third longitudinal member 306 . These slip fit connections are secured by pins 107 . Coupler 108 is attached to the outboard end of frame extension 102 , and is adaptable to allow connection to any standard trailer hitch configuration.
Referring back to FIG. 2 , castor assembly 210 can be seen. Castor assembly 210 is comprised of castor 204 , castor leg 205 , and castor leg receiver 206 . In this embodiment, castor leg 205 is constructed of tube steel with a flat plate welded to the outboard end of castor leg 205 . Castor leg 205 is adapted to allow mounting of castor 204 to the flat plate at its outboard end, and to provide a removable, slip fit connection with castor leg receiver 206 at its inboard end. As also can be seen in FIG. 2 , castor assembly 210 is designed such that, once it is in place, transportable storage container 100 is level. In this embodiment, there are two castor assemblies 210 .
As can be seen in FIG. 1 and FIG. 2 , wheel system 208 fits within wheelwell 202 . Wheelwell 202 is recessed into transportable storage container 100 and is sized to be at least as wide as wheel 301 and at least as tall as the amount of suspension travel provided by suspension 201 .
In operation, transportable storage container 100 may be towed behind a truck or other suitable vehicle with a standard trailer hitch. Coupler 108 is adaptable to connect transportable storage container 100 to standard trailer hitch configurations. Once transportable storage container 100 has been towed to the desired destination, transportable storage container 100 is de-coupled from the tow vehicle, and two castor assemblies 210 are connected to transportable storage container 100 . Frame extension 102 can then be disconnected from frame 300 . At this point, transportable storage container 100 is easily rolled by a single person to the desired work location. Further, transportable storage container 100 is designed to be narrow enough to fit through standard door openings, and because wheel systems 203 and castor assemblies 210 do not increase the rolling width of transportable storage container 100 , the width of transportable storage container 100 may be maximized, thereby increasing the available storage capacity, without sacrificing the ability to easily move transportable storage container 100 around a job site. Because wheel systems 208 do not have to be removed or installed to transition transportable storage container 100 from jobsite mode to transportation mode, the process of changing between these modes is greatly simplified.
While exemplary systems and methods embodying the present invention are shown by way of example, it should be understood that the invention is not limited to these embodiments. Modifications can be made by those skilled in the art, particularly in light of the foregoing teachings. For example, each of the elements of the aforementioned embodiments may be utilized alone or in combination with elements of other embodiments. | A transportable storage container for securely storing construction tools that is readily moved around the job site by a single person and is readily towed behind a vehicle without the need to load and unload the storage container prior to and after transportation. | 1 |
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a delay locked loop circuit, and more particularly to a delay locked loop circuit capable of improving a signal processing time and reducing a device area.
[0003] 2. Description of the Prior Art
[0004] As generally known in the art, a delay locked loop circuit synchronizes a phase of a clock signal externally applied to a semiconductor device with a phase of a clock signal used in the semiconductor device.
[0005] In particular, since the delayed locked loop circuit, which is used for high-speed synchronization memory devices such as DDR SDRAM, determines an operation frequency band of the memory devices and exerts serious influence on an operation time_characteristic, the high-speed synchronization memory devices include a high-performance delay locked loop circuit having a wide frequency band and a low jitter characteristic.
[0006] FIG. 1 illustrates a block diagram of a typical delayed locked loop circuit.
[0007] As shown in FIG. 1 , the delay locked loop circuit includes a clock buffer 100 for receiving a clock signal /CLK, a clock buffer 101 for receiving an external clock signal CLK, a delay part 110 for receiving an output signal fclk 2 of the clock buffer 100 and an output signal rclkt 2 of the clock buffer 101 , a delay part 120 for receiving output signals Fclk 2 _dly and Rclk 2 _dly of the delay part 110 , a clock divider 130 for dividing the output signal rclkt 2 of the clock buffer 101 , a replica delay part 150 for receiving an output signal fb_dly 2 of the delay part 120 and delaying the output signal fb_dly 2 by a predetermined time, and a phase comparator 140 for comparing a phase of an output signal of the replica delay part 150 with a phase of an output signal ref of the clock divider 130 .
[0008] The delay part 110 includes a plurality of delay lines 11 to 13 , a shift register 13 , and a shift controller 15 . Also, the delay part 120 includes a plurality of delay lines 16 to 18 , a shift register 19 , and a shift controller 20 .
[0009] Generally, the delay part 110 has a delay time longer than that of the delay part 120 . That is, the delay part 110 adjusts a coarse delay time, and the delay part 120 adjusts a fine delay time.
[0010] The shift controller 15 receives an output signal of the phase comparator 140 and controls a shift register 14 . The shift register 14 controls delay times of the delay lines 11 to 13 .
[0011] A shift comparator 160 compares a phase of an output signal (ref) of the clock divider 130 with a phase of an output signal of a replica delay part 150 and is controlled by the shift controller 15 .
[0012] The shift comparator 160 applies the output signal thereof to the shift controller 20 . The shift controller 20 controls the shift register 19 so as to adjust a delay time of the delay lines 16 to 18 .
[0013] A locking part 180 receives an output signal of the phase comparator 160 and an output signal Dll_lockz of the shift controller 20 . Also, when output of the locking part 180 is enabled, the locking part 180 controls the shift register 19 so as to fix the delay time of the delay lines 16 to 18 .
[0014] As shown in FIG. 1 , a driver 170 receives an output signal of the delay line 16 , and a driver 171 receives an output signal of the delay line 17 . The drivers 170 and 171 output signals fclk_dll and rclk_dll.
[0015] As shown in FIG. 1 , the CLK and /CLK denote external clock signals. A phase of the CLK is an inverted phase of the /CLK. The clock buffers 100 and 101 receive the external clock signals CLK and /CLK, and are buffer circuits for converting a voltage level of the clock buffers into a voltage level (e.g., CMOS level) used in a semiconductor device.
[0016] The delay part 110 delays the output signals fclk 2 and rclkt 2 of the clock buffers 100 and 101 by a predetermined time. As described above, the delay part 110 includes a plurality of the delay lines 11 to 13 , and a delay time of the delay part 110 are controlled by the shift controller 15 and the shift register 14 .
[0017] The clock divider 130 generates a predetermined reference clock by dividing a frequency of a clock signal rclkt 2 outputted from the clock buffer 101 at the ratio of 1/n (generally, n may be ‘4’, ‘8’, ‘16’, etc as an integer).
[0018] The clock divider 130 applies an output signal ref thereof to the delay line 13 after delaying the output signal ref by a predetermined time. The output signal passing through the delay line 13 is applied to the delay line 18 . The delay line 18 applies the output signal fb_dly 2 thereof to the replica delay part 150 .
[0019] The replica delay part 150 is a delay circuit having delay times tD 1 and tD 2 obtained by adding a delay time tD 1 of the clock buffer 100 to a delay time tD 2 of the output driver 170 .
[0020] For reference, as shown in FIG. 1 , the output signal fclk 2 of the clock buffer 100 is outputted in synchronization with a rising edge of the external clock signal /CLK, and the output signal rclkt 2 of the clock buffer 101 is outputted in synchronization with a rising edge of the external clock signal CLK. The output signal Fclk 2 _dly of the delay line 11 is a signal obtained by delaying the output signal fclk 2 of the clock buffer 100 by a predetermined time, and the output signal Rclk 2 dly of the delay line 12 is a signal obtained by delaying the output signal rclkt 2 of the clock buffer 101 .
[0021] FIG. 2 illustrates the delay parts 110 and 120 by way of example in detail. That is, a delay part 200 shown in FIG. 2 is identical to delay parts 110 and 120 shown in FIG. 1 .
[0022] As shown in FIG. 2 , the delay part 200 includes a delay line 21 . Signals RCLK, FCLK, and In_lock applied to the delay line 21 indicate the signals rclkt 2 , Rclk 2 _dly, fclk 2 , and Fclk 2 _dly applied to the delay lines shown in FIG. 1 . A shift register 22 and a shift controller 23 shown in FIG. 2 indicate the shift registers 14 and 19 and the shift controllers 15 and 19 shown in FIG. 1 .
[0023] As known to those skilled in the art, a delay time of a unit cell can be adjusted according to logical levels of an output signal outputted from a shift register.
[0024] Hereinafter, a basic operation of the conventional delay locked loop circuit shown in FIGS. 1 and 2 will be described.
[0025] The phase comparator 140 compares a phase of an output signal of the replica delay part 150 with a phase of an output signal ref of the clock divider 130 and sends a predetermined control signal to the shift controller 150 . The shift register 15 controls the shift register 14 , and the shift register 14 controls the delay lines 11 to 13 . The delay part 120 performs an operation similar to that of the delay part 110 . The above-mentioned procedure is repeated until there is no phase difference, which is a result of the phase comparator 140 .
[0026] However, the conventional delay locked loop circuit shown in FIG. 1 has the following problems.
[0027] First, it is necessary to increase the number of unit delay circuits included in the delay line 102 in order to operate the delay locked loop circuit in a wide frequency band.
[0028] Also, if the number of the unit delay circuits is increased, an area occupied by the delay parts 110 and 120 is large.
[0029] In addition, the more the number of the unit delay circuits is, the more power consumption is.
SUMMARY OF THE INVENTION
[0030] Accordingly, the present invention has been made to solve the above-mentioned problems occurring in the prior art, and an object of the present invention is to provide a delay locked loop circuit having a fast locking function and a relatively reduced delay line area.
[0031] Another object of the present invention is to provide a delay locked loop circuit having a fast locking function by including a unit for detecting levels of frequencies (lengths of periods) of external clock signals (CLK and CLKB).
[0032] In order to accomplish this object according to an aspect of the present invention, there is provided a delay locked loop circuit comprises a first delay part for receiving an external clock signal and outputting it after delaying a predetermined time; a first clock divider for dividing a frequency of the external clock signal into 1/n (n is a natural number of at least two); a second clock divider for dividing an output signal from the first delay part into 1/n (n is a natural number of at least two); and a second delay part for receiving an output signal from the second clock divider and outputting it after delaying a predetermined time; wherein the predetermined delay time of the first delay part is controllable by using a result of a phase difference between a phase of the output signal of the first clock divider and a phase of the output signal of the second delay part; and the output signal of the first delay part is an output signal of the delay locked loop circuit.
[0033] According to the present invention, the external clock signal is one of the signals CLK and /CLK which are input to a synchronous memory device. Also, the present invention further comprises a phase comparator for comparing the phase difference between a phase of the output signal of the first clock divider and a phase of the output signal of the second delay part; and a controller for controlling the predetermined delay time of the first delay part in response to an output signal of the phase comparator. Herein, when the phase of the output signal of the first clock divider is coincided with the phase of the output signal of the second delay part, the controller stops the operation of controlling the predetermined delay time of the first delay part.
[0034] In order to accomplish this object according to another aspect of the present invention, there is provided a delay locked loop circuit comprising: a first clock buffer for outputting a first clock signal in synchronization with a rising edge of an external clock signal; a second clock buffer for outputting a second clock signal in synchronization with a falling edge of the external clock signal; a multiplexer for selecting and outputting one of the first clock signal and the second clock signal; a first delay part for receiving an output signal of the multiplexer and having a first delay line, a first shift register, and a first shift controller; a second delay part for receiving an output signal of the first delay part and having a second delay line, a second shift register, and a second shift controller; a first clock divider for dividing a frequency of an output signal of the multiplexer into 1/n (n is a natural number of at least two); a second clock divider for dividing a frequency of an output signal of the second delay part into 1/n (n is a natural number of at least two); a third delay part for receiving an output signal of the second clock divider; a first phase comparator and a second phase comparator for comparing a phase of an output signal of the first clock divider with a phase of an output signal of the third delay part; and a delay time fine adjustment part for receiving the output signal of the second delay part and finely adjusting a phase of the output signal of the second delay part. According to the present invention, the first delay line receives the output signal of the multiplexer, the second delay line receives the output signal of the first delay line, the delay time fine adjustment part receives the output signal of the second delay line, the first shift controller received the output signal of the first phase comparator controls the first shift register and adjusts a delay time of the first delay line, and the second shift controller received the output signal of the second phase comparator controls the second shift register and adjusts a delay time of the second delay line.
[0035] According to the present invention, when the phase of the output signal of the first clock divider is synchronized with the phase of the output signal of the third delay part within allowance, the second shift controller controlled by the second phase comparator controls the second shift register so as to fix a delay time of the second delay line.
BRIEF DESCRIPTION OF THE DRAWINGS
[0036] The above and other objects, features and advantages of the present invention will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which:
[0037] FIG. 1 is a block diagram of a typical delay locked loop circuit;
[0038] FIG. 2 illustrates delay parts shown in FIG. 1 by way of example in detail;
[0039] FIG. 3 is a block diagram of a delay locked loop circuit according to the present invention;
[0040] FIG. 4 illustrates a multiplexer and a delay part shown in FIG. 3 by way of example in detail; and
[0041] FIG. 5 illustrates a delay time fine adjustment shown in FIG. 3 by way of example.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0042] Hereinafter, a preferred embodiment of the present invention will be described with reference to the accompanying drawings. In the following description and drawings, the same reference numerals are used to designate the same or similar components, and so repetition of the description on the same or similar components will be omitted.
[0043] FIG. 3 illustrates a block diagram of a delay locked loop circuit according to the present invention.
[0044] As shown in FIG. 3 , the delay locked loop circuit includes a clock buffer 300 for receiving an external clock signal /CLK, a clock buffer 301 for receiving an external clock signal CLK, a multiplexer 31 for receiving an output signal fclk 2 of the clock buffer 300 and an output signal rclkt 2 of the clock buffer 301 , a delay part 310 for receiving an output signal clk 2 of the multiplexer 31 , a delay part 320 for receiving an output signal clk 2 _dly of the delay part 310 , a clock divider 330 for receiving an output signal clk 2 of the multiplexer 31 , a clock divider 350 for receiving an output signal clk 2 _dly 2 of the delay part 320 , a replica delay part 360 for receiving an output signal of the clock divider 350 , a phase comparator 340 for comparing a phase of an output signal Feedback of the replica delay part 360 with a phase of an output signal ref of the clock divider 130 , a phase comparator 370 for comparing a phase of an output signal ref of the clock divider 330 with a phase of an output signal of a shift control part 34 , and a delay time fine adjustment part 380 for receiving an output signal clk 2 _dly 2 of the delay part 320 and finely adjusting a delay time.
[0045] As shown in FIG. 3 , the delay part 310 includes a delay line 32 , a shift register 33 , and a shift controller 34 . Also, the delay part 320 includes a delay line 35 , a shift register 36 , and a shift controller 37 . The delay part 310 has a delay time longer than that of the delay part 320 . That is, the delay part 310 adjusts a coarse delay time, and the delay part 320 adjusts a fine delay time.
[0046] The shift controller 34 receives an output signal of the phase comparator 340 and controls a shift register 33 . The shift register 33 controls a delay time of the delay line 32 .
[0047] The shift comparator 370 compares a phase of an output signal ref of the clock divider 330 with a phase of an output signal Feedback of a replica delay part 360 .
[0048] The shift comparator 370 applies the output signal thereof to a shift controller 37 . The shift controller 37 controls the shift register 36 so as to adjust a delay time of the delay line 35 .
[0049] A locking part 390 receives an output signal of the phase comparator 370 and an output signal Dll_lockz of the shift controller 37 . Also, when output of the locking part 390 is enabled, the locking part 390 controls the shift register 36 so as to fix the delay time of the delay line 35 .
[0050] Hereinafter, signals of a circuit shown in FIG. 3 and an operation of each component of the circuit will be described.
[0051] As shown in FIG. 3 , the CLK and the /CLK denote external clock signals. A phase of the CLK is an inverted phase of the /CLK. The clock buffers 300 and 301 receive the external clock signals CLK and /CLK, and are buffer circuits for converting a voltage level of the clock buffers into a voltage level (e.g., CMOS level) used in a semiconductor device. An output signal fclk 2 of the clock buffer 300 is outputted in synchronization with a rising edge of the external clock signal /CLK, and an output signal rclkt 2 of the clock buffer 301 is outputted in synchronization with a rising edge of the external clock signal CLK.
[0052] The multiplexer 31 selectively one of output signals of the clock buffers 300 and 301 .
[0053] The multiplexer 31 applies an output signal clk 2 to the delay part 310 , and the delay part 310 applies an output signal clk 2 _dly to the delay part 320 .
[0054] The delay part 320 applies an output signal clk_dly 2 thereof to the delay time fine adjustment part 380 . Also, the delay part 320 applies the output signal clk_dly 2 to the clock divider 350 . The signal clk_dly 2 applied to the clock divider 350 is outputted to the clock divider 350 after the period thereof is increased by four times, eight times, etc. The clock divider 350 has the same division ratio as the clock divider 330 .
[0055] The replica delay part 360 outputs the output signal of the clock divider 350 after delaying the output signal by a predetermined time.
[0056] The replica delay part 360 applies the output signal Feedback thereof to the phase comparators 340 and 370 .
[0057] The phase comparator 340 compares a phase of a reference voltage ref outputted from the clock divider 330 with a phase of the output signal Feedback of the replica delay part 360 . It is preferred that there is no phase difference.
[0058] The phase comparator 370 compares the phase of a reference voltage ref outputted from the clock divider 330 with the phase of the output signal Feedback of the replica delay part 360 , and is controlled by the shift controller 34 .
[0059] The phase comparator 370 applies an output signal thereof to the shift register 37 and the locking part 390 .
[0060] The shift controller 37 controls the shift register 36 so as to finely adjust the delay line 35 .
[0061] When an output signal Dll_lockz of the shift controller 37 is enabled to be a low level, the locking part 390 controls the shift register 36 so as to fix a delay time of the delay line 35 .
[0062] FIG. 4 illustrates the multiplexer 31 and the delay part 310 shown in FIG. 3 in detail by way of example. For reference, a multiplexer 410 and a delay part 400 shown in FIG. 4 correspond to the multiplexer 31 and the delay part 310 shown in FIG. 3 , respectively. Also, a circuit of the delay part 400 shown in FIG. 4 is used for the delay part 320 shown in FIG. 3 . A shift register 42 and a shift controller 43 shown in FIG. 4 imply shift registers 33 and 35 and shift controllers 34 and 37 shown in FIG. 3 .
[0063] As shown in FIG. 4 , the delay part 400 includes a delay line 41 , the shift register 42 , and the shift controller 43 .
[0064] The multiplexer 410 selectively applies one of output signals rclk 2 and fclk 2 to the delay line 41 by using control signals rclk and fclk.
[0065] FIG. 5 illustrates the delay time fine adjustment part 380 shown in FIG. 3 by way of example.
[0066] As shown in FIG. 5 , the delay time fine adjustment part 380 receives an output signal clk_dly 2 of the delay line 35 , and then, the output signal clk_dly 2 is included in a circuit for an RC delay. As shown in FIG. 5 , a control signal LOAD<0:7> applied to a transistor is selectively enabled, and a capacitor connected to each transistor is linked with a line for delivering the output signal clk_dly 2 , so that the RC delay is adjusted. Herein, the transistors may have the same sizes or difference sizes.
[0067] Hereinafter, an operation of the delay locked loop circuit according to the present invention with reference to FIGS. 3 to 5 will be described.
[0068] The delay locked loop circuit shown in FIG. 3 has an operation similar to that of a typical delay locked loop circuit.
[0069] As known to those skilled in the art, the delay locked loop circuit adjusts delay times of the delay lines 32 and 35 in such a manner that a phase of a signal passing through the clock divider 330 is synchronized with a phase of a signal passing through the replica delay part 360 .
[0070] However, the delay locked loop circuit according to the present invention is different from the conventional delay locked loop circuit in view of a circuit structure, in that only one of the external clock signals CLK and /CLK is used in the delay locked loop circuit according to the present invention.
[0071] That is, as shown in FIG. 3 , according to the present invention, one signal from the signals fclk 2 and rclk 2 passing through the clock buffers 300 and 301 is selected by means of the multiplexer 31 and applied to the delay line 32 .
[0072] Accordingly, differently from the conventional technique, the number of delay lines included in the delay part is reduced. Therefore, an area of the delay part can be reduced.
[0073] Also, according to the present invention, the delay time fine adjustment part 380 is provided, so that a phase of an output signal of the delay line 320 is finely adjusted.
[0074] According to the present invention, the delay part 310 more precisely adjusts a delay time as compared with the delay part 320 . That is, the delay part 310 adjusts a coarse delay time, and the delay part 320 more precisely adjusts a delay time.
[0075] The delay time fine adjustment part 380 adjusts a delay time more precisely than the delay part 320 .
[0076] As described above, according to the present invention, a delay locked loop circuit is realized by using only one external clock signal, so that an area of a delay part can be minimized. Therefore, the delay locked loop circuit is useful in designing a high integrated circuit.
[0077] Although a preferred embodiment of the present invention has been described for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims. | Disclosed is a delay locked loop circuit (DLL) used for DDR SDRAM. The DLL provides a fast locking function. In particular, the DLL detects the level of a frequency and performs the fast locking function, thereby realizing a high integrated memory device having a reduced area of a delay part used in order to synchronize a phase of an external clock signal with a phase of an internal clock. | 7 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an indirect heating furnace suitable for heat treatment of solid inorganic substances, more particularly, for high-temperature heat treatment in cases where direct contact of the solid inorganic substance with high-temperature combustion gas is unfavorable.
2. Description of the Related Arts
In a solid heating process in which direct contact of a substance to be heated with high-temperature combustion gas is unfavorable, an indirect heating furnace (also called an external heating furnace) is generally used.
However, conventional Indirect heating furnaces use metallic shells for reaction tubes. This limits the conventional indirect heating furnace to heating processes requiring temperatures no higher than 900° C.
To overcome this problem, U.S. Pat. No. 5,846,072 (Patent Literature 1) has described that an indirect heating furnace in which the reaction tube is made of ceramics and a screw conveyor is provided in the reaction tube to convey a solid substance to be heated, by which the Indirect heating furnace can be applied to processes requiring temperatures above 900° C.
FIG. 4 shows an example of a general system configuration in the case where a substance to be heated is heat-treated using such an indirect heating furnace provided with a ceramic reaction tube. In the example shown in FIG. 4, a case where lime is burned (thermal decomposition of limestone) is illustrated.
In FIG. 4, limestone charged into a supply chamber 120 through a raw material charge port 110 is transferred in a reaction tube 140 by the rotation of a screw conveyor 130 , and conveyed into an outlet chamber 150 . The limestone is subjected to heat treatment during the time when it is passed through the reaction tube 140 toward the outlet chamber 150 . The heat-treated product in the outlet chamber 150 is discharged to the outside of the furnace through a chute 160 .
Outside the tube, high-temperature combustion gas, which is generated by a combustion burner 170 , is introduced into the furnace through a gas introduction port 180 to heat the limestone in the reaction tube 140 indirectly via the wall of the reaction tube 140 , and is discharged from the furnace through an exhaust port 190 . The furnace exhaust gas discharged through the exhaust port 190 is sent to an air preheater 200 to preheat combustion air supplied to the combustion burner 170 , by which the heating value of the furnace exhaust gas is utilized effectively.
In the indirect heating furnace as shown in FIG. 4, heating is accomplished in three steps, in that heat is transferred from the high-temperature combustion gas supplied into the furnace to the outside wall of the reaction tube 140 , it is conducted through the tube wall, and then the heat is transferred from the tube wall to limestone, which is a substance to be heated. Because of this, the heat transfer efficiency is poor, and the temperature of furnace exhaust gas is as high as about 1000° C. In order to preheat the combustion air using a conventional metallic air preheater 200 with this high-temperature furnace exhaust gas, it is necessary first to lower the gas temperature to about 800° C. by using dilution air to prevent the air preheater from being burned out.
When furnace exhaust gas of about 800° C. is used, the temperature of the obtained preheated air is about 600° C. at the most. Therefore, the heat recovery efficiency is poor, and a large amount of excess heat is wasted. It might be thought that this excess heat can be used to preheat limestone, which is a substance to be heated. However, since this system is used for a process in which direct contact of the substance to be heated with high-temperature combustion gas is unfavorable, the preheating of the substance should also be accomplished indirectly. Thus, it is difficult to improve the thermal efficiency in this way. Further, the amount of exhaust gas discharged from the system increases due to the dilution air, which results in a further increase in heat loss.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an indirect heating furnace which can improve the thermal efficiency dramatically and can increase the throughput significantly in a solids heating process in which direct contact of the solids with high-temperature combustion gas is unfavorable.
To achieve the above object, the present invention provides the following indirect heating furnaces:
[1] An indirect heating furnace for heating a substance in a reaction tube with a high-temperature combustion gas that does not contact that substance, characterized in that the heating takes place in a stationary ceramic reaction tube, and the combustion device supplying the heating high-temperature combustion gas into the furnace is comprised of at least one pair of regenerative burners.
[2] The indirect heating furnace as described in the above item [1], characterized in that the temperature of the high-temperature combustion gas supplied into the furnace is 1000° C. or higher.
[3] The indirect heating furnace as described in the above item [1] or [2], characterized in that the furnace has a screw conveyor for transporting the substance to be heated through the reaction tube, and the essential portion of the screw conveyor is made of ceramics.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic configuration view showing one embodiment of an indirect heating furnace in accordance with the present invention;
FIG. 2 is a graph showing the measurement results of temperature distribution in a heating chamber and temperature distribution of powdered lime in a reaction tube in the case where powdered lime is burned by using the indirect heating furnace in accordance with the present invention shown in FIG. 1, as an example;
FIG. 3 is a graph showing the measurement results of temperature distribution in a heating chamber and temperature distribution of powdered lime in a reaction tube in the case where powdered lime is burned by using the indirect heating furnace of the related art shown in FIG. 4, as a comparative example; and
FIG. 4 is a schematic view showing one example of general system configuration in the case where a substance to be heated is heat-treated using an indirect heating furnace of the related art which is provided with a ceramic reaction tube.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 is a schematic configuration view showing one embodiment of an indirect heating furnace in accordance with the present invention.
An indirect heating furnace 1 shown in FIG. 1 includes a solid supply chamber 2 into which a solid inorganic substance, which is a substance to be heated, is charged, a heating chamber 3 into which high-temperature combustion gas is supplied, and a product outlet chamber 4 from which a heated product is discharged to the outside of furnace.
In the heating chamber 3 , a ceramic reaction tube 5 is arranged to heat the substance to be heated. One end of the reaction tube 5 communicates with the solid supply chamber 2 , and the other end thereof communicates with the product outlet chamber 4 . The reaction tube 5 is mounted by being fixed on refractories such as fiber block or castable forming the furnace wall of the heating chamber 3 , and the inside of the reaction tube 5 and the heating chamber outside the tube are isolated from each other in a gastight manner.
At introduction/exhaust ports 6 a and 6 b , a pair of regenerative burners 7 a and 7 b are provided, respectively, to furnish the heating gas to heating chamber 3 . The regenerative burner includes two burners in each set, and the number of sets of provided burners can be changed appropriately according to the scale, operating condition, etc. of the furnace.
The ceramic reaction tube 5 is stationary. Conventionally, a horizontal cylindrical kiln (furnace) in which a metallic shell is used as a reaction tube, is constructed so that the reaction tube is inclined at an angle of 2 to 5 degrees, and by rotating the reaction tube, a content (solid to be heated) is heated while being conveyed toward the outlet. However, in a horizontal cylindrical kiln (furnace) using a ceramic reaction tube, it In difficult to rotate the reaction tube due to strength and deformation tolerance. As an alternative, the reaction tube is not rotated but fixed in a stationary position. The content (solid to be heated) is conveyed by a ceramic screw conveyor provided on the inside, not by rotation of the reaction tube.
As the solid inorganic substance, which is a substance to be heated, for example, ore (octahedrite, bauxite, borax, calcite, chalcopyrite, chromite, hematite, etc.), metal halide (calcium bromide, calcium chloride, calcium fluoride, calcium iodide, similarly, iron (III) halide, iron (II) halide, potassium halide, sodium halide, etc.), metal carbide and metal carbonate (calcium carbonate, etc.), metal oxide (chromite, etc.), metal phosphate (calcium phosphate, etc.), and metal sulfide and metal sulfate (calcium sulfate, etc.) can be cited.
The ceramic reaction tube 5 may be formed of, for example, high-purity MgO, high-purity alumina, silicon carbide, beryllia, silicon nitride, boron carbide, or any other ceramic material having relatively high thermal conductivity.
The following is a description of a case where lime is burned (thermal decomposition of limestone) using the indirect heating furnace 1 shown in FIG. 1 .
In FIG. 1, limestone charged into the solid supply chamber 2 through a raw material charge part 8 is transported through the reaction tube 5 by the rotation of a screw conveyor 9 , and it is dropped into the product outlet chamber 4 . The limestone is subjected to heat treatment during the time when it is passing through the reaction tube 5 . The heated product in the product outlet chamber 4 is discharged from the furnace through a chute 10 .
Outside the tube, high-temperature combustion gas, which is generated by the regenerative burner 7 a , is introduced into the heating chamber 3 through the gas introduction/exhaust port 6 a to heat the limestone in the reaction tube 5 indirectly via the wall of the reaction tube 5 . It is discharged from the furnace through the gas introduction/exhaust port 6 b and the regenerative burner 7 b as a furnace exhaust gas.
The screw conveyor 9 is preferably made of ceramics so that it does not burn out. Thus, even when a heating gas of a high temperature is used, the substance to be heated can be transferred stably. Any of the same ceramics material of construction listed for the reaction tube 5 can be used for the screw conveyor parts, except that relatively lower thermal conductivities are preferred for this service.
The following is a description of a method for Introducing high-temperature combustion gas into the heating chamber 3 by using the paired regenerative burners 7 a and 7 b.
Combustion air of ordinary temperature, which is blown by a blower, not shown, or the like, is introduced to the regenerative burner 7 a through a switching valve 11 . The combustion air introduced into the regenerative burner 7 a passes through a heat reservoir that was heated to a high temperature in the previous cycle. During this time, it is heated to nearly that temperature by the heat stored in the heat reservoir. The heated combustion air is mixed with a fuel supplied separately into the regenerative burner 7 a , and the high-temperature gas generated by the combustion is introduced into the heating chamber 3 through the gas introduction/exhaust port 6 a . Some combustion also occurs in the heating chamber 3 .
A ceramic having high heat capacity is the preferred material for the heat reservoir.
The high-temperature combustion gas introduced into the heating chamber 3 heats limestone in the reaction tube 5 indirectly via the wall of the reaction tube 5 , and subsequently is discharged from the furnace through the gas introduction/exhaust port 6 b , the regenerative burner 7 b , and switching valve 12 as the furnace exhaust gas. The gas being discharged through the gas introduction/exhaust port 6 b passes through a heat reservoir in the regenerative burner 7 b . At this time, the furnace exhaust gas gives sensible heat to the heat reservoir to heat the heat reservoir to a high temperature, and the temperature of the furnace exhaust gas itself decreases.
After the system has been operated in this state for a predetermined period of time, the flow of gas is reversed by revering the switching valves 11 and 12 . For example, combustion air of ordinary temperature, which is blown by a blower or the like, is introduced to the regenerative burner 7 b through the switching valve 11 . This air passes through the heat reservoir that was heated in the previous cycle and during the passage, it is heated to a high temperature by the heat stored in the heat reservoir. The heated combustion air is mixed with a fuel supplied separately into the regenerative burner 7 b , where combustion produces high temperature gases that are introduced into the heating chamber 3 through the gas introduction/exhaust port 6 b . The high-temperature combustion gas in the heating chamber 3 heats limestone inside the reaction tube 5 indirectly via the tube wall, and subsequently this is discharged from the furnace through the gas introduction/exhaust port 6 a , the regenerative burner 7 a , and the switching valve 12 as furnace exhaust gas. This gas also passes through the heat reservoir in the regenerative burner 7 a . At this time, the furnace exhaust gas gives sensible heat to the heat reservoir, thus heating the heat reservoir to a high temperature, and the temperature of the furnace exhaust gas itself decreases.
Thus, one of the paired regenerative burners is used for combustion, while the other is used for heat reserve, and the role of the regenerative burners is switched over at time intervals of about 20 to 30 seconds. Thereby, the combustion air supplied to the burner of the combustion side always passes through a hot heat reservoir, so that the air is preheated to high temperatures. The preheated air reaches temperatures only about 50 to 60° C. lower than the temperature of the furnace exhaust gas. That is to say, when the temperature of furnace exhaust gas is about 1100° C., preheated air of about 1050° C. can be obtained, so that the thermal efficiency increases significantly. Further, by heating the combustion air to high temperature, its reactivity with fuel is improved greatly, which also contributes to the stability of combustion. As a result, the concentration of nitrogen oxides generated by combustion in the regenerative burner can be kept at a very low level.
Another advantage in using the regenerative burner is that, because the flow of gas in the heating chamber 3 is reversed at predetermined time intervals, gas mixing in the heating chamber 3 is promoted, and hence the temperature distribution in the combustion chamber 3 can be uniformly high. As a result, the heat transferred to the substance to be heated per unit length of the reaction tube 5 increases greatly as compared to the conventional heating methods that don't use regenerative burners. Therefore, when the throughput is equal, the furnace size can be decreased. Or, when the furnace size is equal, the throughput can be increased significantly.
The time interval for switching over the regenerative burners can be changed appropriately according to the number of sets of provided regenerative burners, the scale and operating condition of furnace, and the like.
The high-temperature combustion gas supplied from the regenerative burner 7 a (or 7 b ) into the heating chamber 3 preferably has a temperature of 1000° C. or higher, so that heating of the substance to be heated, which is based on radiant heat transfer, can be accomplished more effectively. Also, the temperature of the heat reservoir due to the furnace exhaust gas will be correspondingly high, increasing the preheated temperature of the combustion air, and hence the combustion efficiency is further improved.
The upper temperature limit of the combustion gas in determined by the heat resistance of the ceramic reaction tube 3 , which can be 1500° C. or even higher.
For the regenerative burner, besides the switch-over type in which two burners are used in a pair, another method can be used, wherein heating of combustion air and heat recovery from the furnace exhaust gas are accomplished with one burner by turning the heat reservoir in the burner.
EXAMPLE
FIG. 2 shows the measurement results of temperature distribution in the heating chamber 3 and temperature distribution of powdered lime in the reaction tube 5 in the case where powdered lime is burned by using the indirect heating furnace configured as shown in FIG. 1, as an example.
In this example, two sets of regenerative burners were provided, and the switching-over of the regenerative burners was accomplished at time intervals of 20 seconds. As a result, the temperature inside the heating chamber 3 was kept substantially uniform at about 1200° C. by the heat storage effect of refractories forming the furnace wall.
In burning powdered lime, the throughput was controlled so that the temperature of powdered lime going to the product outlet chamber was 1050° C.
As a result, the throughput reached 7.2 tons per day. Also, the fuel combustion rate during burning was 37 kg/h of kerosene, and the heat unit requirement per product unit mass at this time was 5600 kJ/kg.
FIG. 3 shows the measurement results of temperature distribution in the heating chamber 3 and temperature distribution of powdered lime in the reaction tube 5 in the case where powdered lime is burned by using the indirect heating furnace of the related prior art shown in FIG. 4, as a comparative example.
The temperature distribution in the heating chamber 3 is such that the furnace inlet temperature from the combustion burner 170 is about 1200° C., and the furnace gas exit temperature is about 1000° C.
In burning powdered lime, as in the case of the previous example, the throughput was controlled so that the temperature of powdered lime going to the outlet chamber was 1050° C.
As a result, the throughput was 5.8 tons per day. Also, the fuel consumption rate was 40 kg/h of kerosene, and the heat unit requirement per product unit mass in this case was 7500 kJ/kg.
As described above, in the indirect heating furnace in accordance with the present invention, it was confirmed that the thermal efficiency can be improved dramatically as compared with the conventional configuration (unit heat requirement was improved from 7500 kJ/kg to 5600 kJ/kg) and further the throughput can be increased significantly (from 5.8 t/d to 7.2 t/d).
As described above, the present invention is an indirect heating furnace which can improve thermal efficiency dramatically, and which can increase the throughput significantly, compared to the furnace that is described by U.S. Pat. 5,846,072. | An indirect heating furnace heats a substance in a reaction tube with a high-temperature combustion gas without contact between the substance and the combustion gas. The reaction tube is a stationary ceramic tube. A combustion device for supplying said heating high-temperature combustion gas into the furnace in comprised of at least one pair of regenerative burners. | 5 |
BACKGROUND OF THE INVENTION
The present invention relates to folding apparatus and, more particularly, to an apparatus and method for folding airbags.
Use of airbags for driver and passenger restraint during vehicle impact has grown increasingly popular. Typically, airbags are circular, oval or pillow-shaped. They are commonly mounted in steering wheels, steering columns, and dashboards of automobiles. Only a limited space is available for airbag storage. Accordingly, airbags must be folded to fit within the limited space available for their storage. However, the airbags must also be capable of unfolding and inflating rapidly without binding.
Currently, there are many methods by which an airbag may be folded into a desired configuration or pattern. Oftentimes, these methods are performed manually. Manual methods, however, are costly and usually result in airbags having inconsistent folds.
It is not uncommon for each automotive manufacturer to have its own folding pattern. For any particular folding pattern, new methods and apparatus are desired which will reduce costs and improve the consistency of the folds created in the airbags.
SUMMARY OF THE INVENTION
In accordance with a first aspect of the present invention, an apparatus is provided for folding an airbag for subsequent installation and use in an automotive vehicle. The apparatus comprises: means for supporting an airbag to be folded; means for securing an airbag in position relative to the supporting means; a carriage movable towards and away from the supporting means and the securing means; means associated with the carriage for clamping a first portion of the airbag to the supporting means; first and second folding means associated with the carriage for grasping second and third portions of the airbag and creating first folds in the airbag to form a partially folded airbag; and, means for engaging the partially folded airbag for maintaining the first folds in the partially folded airbag. The securing means further serves to rotate the engaged partially folded airbag about a vertical axis. The first and second folding means additionally serve to grasp opposing portions of the partially folded airbag for creating second folds in the partially folded airbag to form a completely folded airbag.
The first folding means comprises a first pair of folding blades supported by first carrier means for transverse movement along a first axis and for rotational movement about a second axis which is generally transverse to the first axis. The second folding means comprises a second pair of folding blades supported by a second carrier means for transverse movement generally along the first axis and for rotational movement about a third axis which is generally transverse to the first axis. The clamping means comprises a pivotable blade positioned between the first and second folding means.
The supporting means comprises: first and second spring-biased plates; third and fourth plates which are vertically movable; and fifth and sixth plates which are horizontally movable.
The airbag includes a can portion secured to an inflatable bag portion. The securing means comprises a fixture, grippers associated with the fixture for locking the can portion to the fixture, and means for rotating the fixture about the vertical axis.
The engaging means comprises: a main support; means for reciprocating the main support towards and away from the supporting means; means for rotating the main support about a vertical axis; and, a plurality of reciprocating fold retainers for engaging the airbag. Each of the reciprocating fold retainers comprises a piston/cylinder unit and a rubber engagement member secured to the distal end of the piston/cylinder unit.
The main support includes first and second lower support plates each having at least one engagement pin for engaging a corresponding opening in the fixture. The engaging means further comprises stripper means for engaging the completely folded airbag as the first and second folding means release and move away from the completely folded airbag.
In accordance with a second aspect of the present invention, a method is provided for folding an airbag. The method comprises the steps of: clamping a first portion of the airbag; folding second and third portions of the airbag to create first folds in the airbag to form a partially folded airbag; engaging the partially folded airbag to maintain the first folds in the partially folded airbag; rotating the engaged partially folded airbag about a vertical axis; and, folding opposing portions of the partially folded airbag to create second folds in the partially folded airbag to form a completely folded airbag.
The step of folding second and third portions of the airbag to create first folds in the airbag comprises the steps of: grasping the second portion of the airbag with a first pair of folding blades; grasping the third portion of the airbag with a second pair of folding blades; and, moving the first and second sets of blades toward one another while simultaneously rotating each of the first and second sets of folding blades.
The step of folding opposing portions of the partially folded airbag to form second folds in the partially folded airbag comprises the steps of: grasping one of the opposing portions of the partially folded airbag with the first pair of folding blades; grasping the other of the opposing portions of the partially folded airbag with the second pair of folding blades; and, moving the first and second sets of blades toward one another while simultaneously rotating each of the first and second sets of folding blades.
Accordingly, it is an object of the present invention to provide a method and apparatus which may be applied to fold airbags for subsequent installation and use in an automotive vehicle. It is a further object of the present invention to provide a method and apparatus for grasping, rotating and transversely moving various portions of a workpiece to create various folds therein. These and further objects and features of the present invention will become apparent from the following description, the accompanying drawings and the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a plan view of a folding apparatus constructed in accordance with the present invention;
FIG. 2 is a view taken along line 2--2 in FIG. 1;
FIG. 3 is a view taken along line 3--3 in FIG. 2;
FIG. 4 is a view taken along section line 4--4 in FIG. 1;
FIG. 5 is a plan view of a first folding mechanism of the folding apparatus shown in FIG. 1;
FIG. 6 is a side view of the first folding mechanism shown in FIG. 5;
FIG. 7 is a side view of the stripper mechanism of the folding apparatus shown in FIG. 1;
FIG. 8 is a view along section line 8--8 in FIG. 7;
FIG. 9 is a perspective view of a first table of the folding apparatus of FIG. 1;
FIG. 10 is a side view of the first and second tables and lower tooling of the folding apparatus of FIG. 1;
FIG. 11 is a schematic perspective view showing the tables, pivotable blade and first and second sets of folding blades prior to the folding of an airbag; and
FIGS. 12-20 are sequential views illustrating the folding of an airbag employing the apparatus of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
Reference is now made to FIG. 1, where apparatus 10 for folding an airbag 20 in accordance with the present invention is shown. The airbag 20 comprises a can portion 22 secured to an inflatable bag portion 24, see FIG. 11. The apparatus 10 includes movable support tables 30 which define a bag folding area 31, lower tooling 50 for securing the can portion 22 within the bag folding area 31, a movable carriage 60 which reciprocates towards and away from the bag folding area 31, and upper tooling 70 which reciprocates vertically towards and away from the movable support tables 30, see also FIGS. 2 and 3.
Referring to FIGS. 1 and 9-11, the movable support tables 30 include first and second tables 32 and 34, third and fourth tables 36 and 38, and fifth and sixth tables 40 and 42. The first table 32 comprises a pedestal 32a having at its upper end a plate 32b with four bores 32c extending therethrough. Four bolts 32d-32g pass through the bores 32c and each is threadedly received in a corresponding threaded opening in an upper plate 32h. Positioned about each of the bolts 32d-32g is a spring 32k. The springs 32k act together to bias the upper plate 32h in an upward direction away from the plate 32b.
A first aluminum bar 33a is positioned beneath the plate 32b. The bolts 32d and 32e pass through corresponding bores in the bar 33a. The bar 33a is positioned between the lower surface 32j of the plate 32b and respective head portions 32i of the bolts 32d and 32e. A second aluminum bar 33b is also positioned beneath the plate 32b. The bolts 32f and 32g pass through corresponding bores in the bar 33b. The bar 33b is positioned between the lower surface 32j of the plate 32b and the respective head portions 32i of the bolts 32f and 32g.
The second spring-biased table 34 is constructed in essentially the same manner as the first spring-biased table 32, see FIG. 10. The table 34 includes a pedestal 34a having a plate 34b, a spring-biased upper plate 34h and first and second bars 35a and 35b positioned beneath the plate 34b.
The third table 36 comprises an upper plate 36a connected to a piston/cylinder drive unit 36b, see FIGS. 1 and 3. The drive unit 36b includes first and second guide rods 36c and 36d and a drive piston 36e interposed between the first and second guide rods 36c and 36d. The drive piston 36e is fixedly connected to the plate 36a for vertically reciprocating the plate 36a up and down. The fourth table 38 comprises an upper plate 38a connected to a piston/cylinder drive unit 38b. The drive unit 38b includes first and second guide rods 38c and 38d and a drive piston 38e interposed between the first and second guide rods 38c and 38d. The drive piston 38e is connected to the plate 38a for vertically reciprocating the plate 38a up and down.
The fifth table 40 comprises a plate 40a connected to a piston/cylinder drive unit 40b. The drive unit 40b includes first and second guide rods 40c and 40d and a drive piston 40e interposed between the first and second guide rods 40c and 40d. The drive piston 40e is fixedly connected to the plate 40a for horizontally reciprocating the plate 40a towards and away from the plate 36a. The sixth table 42 comprises an upper plate 42a connected to a piston/cylinder drive unit 42b. The drive unit 42b includes first and second guide rods 42c and 42d and a drive piston 42e interposed between the first and second guide rods 42c and 42d. The drive piston 42e is connected to the plate 42a for horizontally reciprocating the plate 42a towards and away from the plate 38a.
The lower tooling 50 includes a fixture 50a which is adapted to receive and lock into position the can portion 22 of the airbag 20, see FIG. 10. The fixture 50a comprises first and second plates 50b and 50c, first and second guide rods 50d and 50e, first and second piston/cylinder units 50f and 50g interposed between the first and second plates 50b and 50c for vertically moving the first plate 50b relative to the second plate 50c, and a rotary drive unit 50h for rotating the first and second plates 50b and 50c back and forth through an angle of approximately 90°.
The first plate 50b receives on its upper surface the can portion 22 of the airbag 20, see FIG. 10. The can portion 22 is provided with an opening 22b, see FIG. 11. A gripper unit 50j is fixedly connected to the first plate 50b and is provided with first and second grippers 51 which extend through a recess 50i in the first plate 50b. The grippers 51 are movable toward and away from one another. After the can portion 22 has been placed on the upper surface of the first plate 50b, the first and second grippers 51 move apart from one another to grip opposing edge portions of the opening 22b to secure the can portion 22 in position prior to folding. The grippers 51 move toward one another after folding has been completed to release the can portion 22.
First, second and third proximity sensors 50k, 50l and 50m are positioned below the second plate 50c, see FIG. 10. The first and second sensors 50k and 50l are positioned such that the second sensor 50l is positioned directly below and senses the second plate 50c only when the can portion 22 is positioned in a first folding position and the first sensor 50k is positioned directly below and senses the second plate 50c only when the can portion 22 is positioned in a second folding position. The sensor 50m is positioned such that it is below the second guide rod 50e when the can portion 22 is positioned in its first folding position and senses the guide rod 50e when the first plate 50b is in its "down" position. Accordingly, the sensor 50m provides an indication regarding whether the first plate 50b and the can portion 22 are in a raised or a lowered position.
The movable carriage 60 reciprocates towards and away from the bag folding area 31 on guide rods 62a and 62b, see FIGS. 1 and 2. A drive unit 63 comprising back-to-back cylinders is connected at its first end 63a to a support table 80 and at its second end 63b to a bracket 64, see FIG. 2. The movable carriage 60 includes a carriage plate 60a. The bracket 64 is secured to the underside of the carriage plate 60a. The drive unit 63 moves the carriage 60 between a first folding position, shown in FIG. 2, a second folding position, and a retracted position, shown in phantom in FIG. 2.
First, second and third proximity sensors 66a-66c are secured to the carriage 60, see FIG. 1. Pins 68a-68c are staggered along the guide rod 62a. When the carriage 60 is located at its first folding position, the sensor 66a will be across from and sense pin 68a. When the carriage is positioned at its second folding position, the sensor 66b will be across from and sense pin 68b. When the carriage 60 is positioned in its retracted position, the sensor 66c will be across from and sense pin 68c. The proximity sensors 66a-66c generate signals which are received by a control unit 90. Those generated signals indicate to the control unit 90 the position of the carriage 60 along the guide rods 62a and 62b.
Secured to the carriage plate 60a is a clamping mechanism 100 comprising a pivotable blade 102 and a piston/cylinder unit 104, see FIG. 2. Fixedly secured to the pivotable blade 102 is a stop block 103. The piston/cylinder unit 104 is connected to the blade 102 for effecting pivotable movement of the blade 102 about a pin 106.
First and second folding mechanisms 110 and 120 are provided on the carriage 60, see FIGS. 1, 2 and 11. Both the first and second folding mechanisms 110 and 120 reciprocate along guide rails 112 and 114. The first folding mechanism 110 comprises a support plate 110a having a rotary drive unit 110b fixedly secured thereon, see also FIGS. 4-6. A first folding blade 110c is coupled to the rotary drive unit 110b via a hub 110d and a plate 110e weldably secured to the hub 110d. A second folding blade 110f is positioned over the first folding blade 110c and reciprocates along guide rods 110g and 110h towards and away from the first folding blade 110c. A piston/cylinder unit 110i is connected to the first and second blades 110c and 110f and effects reciprocating movement of the second blade 110f relative to the first blade 110c. Because the second blade 110f is coupled to the first blade 110c via the guide rods 110g and 110h and the piston/cylinder unit 110i, rotation of the first blade 110c via the rotary drive unit 110b also effects rotational movement of the second blade 110f.
The support plate 110a reciprocates along the guide rails 112 and 114, which are fixed to the carriage plate 60a, see FIG. 2. A first rodless cylinder 116 is secured to a backing plate 117 which, in turn, is secured to the carriage plate 60a, see FIG. 4. The cylinder 116 includes a first reciprocating member 116a. Fixedly connected to the first member 116a is a second member 116b. A third member 116c is fixedly connected to the support plate 110a and is provided with a recess 116d for receiving the second member 116b. Reciprocating movement of the first and second members 116a and 116b effects reciprocating movement of the support plate 110a along the guide rails 112 and 114 via third member 116c.
The second folding mechanism 120 comprises a support plate 120a having a rotary drive unit 120b fixedly secured thereon, see FIG. 1. A first folding blade 120c is coupled to the rotary drive unit 120b via a coupling 120d comprising a hub and a plate weldably secured to the hub, see also FIG. 11. A second folding blade 120f is positioned over the first folding blade 120c for reciprocating movement towards and away from the first folding blade 120c. Guide rods 120g and 120h and a piston/cylinder unit 120i are connected to the first and second blades 120c and 120f. The piston/cylinder unit 120i effects reciprocating movement of the second blade 120f relative to the first blade 120c. Since the second blade 120f is coupled to the first blade 120c via the guide rods 120g and 120h and the piston/cylinder unit 120i, rotation of the first blade 120c via the rotary drive unit 120b also effects rotational movement of the second blade 120f.
The support plate 120a reciprocates along the guide rails 112 and 114, see FIG. 2. A second rodless cylinder 126 is secured to the backing plate 117. The cylinder 126 includes a first reciprocating member 126a, see FIG. 4. Fixedly connected to the first member 126a is a second member 126b. A third member 126c is fixedly connected to the support plate 120a and is provided with a recess 126d for receiving the second member 126b. Reciprocating movement of the first and second members 126a and 126b effects reciprocating movement of the support plate 120a along the guide rails 112 and 114 via third member 126c.
As shown in FIG. 4, proximity sensors 130a and 130b are provided adjacent to the first and second rodless cylinders 116 and 126. The sensors 130a and 130b sense the inner edges 116a' and 126a' of the first members 116a and 126b when those edges 116a' and 126a' are positioned directly across from the sensors 130a and 130b. When the edges 116a' and 126a' are positioned directly across from the sensors 130a and 130b, the first and second folding mechanisms 110 and 120 are positioned in their second folding positions.
Stop members 118 and 128 are fixedly secured to outer surfaces of the members 116b and 126b, see FIG. 1. First and second piston/cylinder units 119 and 129 are fixedly secured to the plate 117, see FIG. 1. When the units 119 and 129 are actuated, their pistons 119a and 129a extend outwardly for engagement with the first and second stop members 118 and 128 as the first and second folding mechanisms 110 and 120 move outwardly along the guide rails 112 and 114 after first folds have been created in the airbag 20. When the first and second folding mechanisms 110 and 120 have been moved outwardly such that the pistons 119a and 129a are engaged with the stop members 118 and 128, the first and second folding mechanisms 110 and 120 are positioned in their second folding positions.
The upper tooling 70 comprises a hold-down mechanism 140 and a stripper mechanism 150, see FIG. 3. The hold-down mechanism 140 includes a main support 142 having first and second lower plates 142a and 142b, see also FIGS. 2, 7 and 8. Each of the plates 142a and 142b is provided with fixture engagement pins 142c and hold-down elements, such as rubber stoppers 142d. A piston/cylinder unit 144 and first and second guide rods 145 are connected to a support frame 146 via a bracket 146a, see FIGS. 2 and 3. The piston/cylinder unit 144 includes a piston 144a fixedly connected to a plate slide 144b which, in turn, is connected to a rotary actuator 147 via an adapter plate 148, see FIGS. 3 and 7. The rotary actuator 147 is connected to the main support 142 such that reciprocating movement of the piston 144a and slide 144b effects reciprocating movement of the main support 142. Additionally, rotary movement of the rotary actuator 147 effects rotational movement of the main support 142.
Four fold retaining piston/cylinder units 149 are provided on the main support 142. A hold-down element, such as a rubber stopper 149a, is fixedly connected at the distal end of each piston of the piston/cylinder units 149, see FIG. 3. When the main support 142 is lowered to its down position, the pins 142c enter into corresponding openings (not shown) in the upper plate 50b of the fixture 50a.
The stripper mechanism 150 comprises a piston/cylinder unit 152 which is fixedly connected to the lower plate 142a, see FIGS. 7 and 8. The piston 152a of the piston/cylinder unit 152 is connected to a first drive element 154 which, in turn, is fixedly connected to a shaft 155. Thus, movement of the piston 152a and, hence, the first drive element 154, effects rotational movement of the shaft 155. A second drive element 156 is also fixedly connected to the shaft 155 for rotational movement therewith. A shaft 157 extends transversely through and is fixed to the distal end 156a of the second drive element 156. First and second stripper fingers 157a and 157b are fixedly connected to opposing ends of the shaft 157. Thus, when the piston 152 is in its retracted position, such as shown in FIG. 7, the stripper fingers 157a and 157b are in their "down" position. Conversely, when the piston 152 is in its extended position, the stripper fingers 157a and 157b move to their "up" position.
A light curtain is defined about the outer perimeter of the apparatus 10 via a light source 160, first, second and third mirrors 162a-162c and a photodetector 164, see FIG. 1. When the light curtain is broken, the apparatus 10 is shut-down by the processor 90.
The processor 90 receives signals generated by each of the sensors set out herein and controls the operation of each of the piston/cylinder units to effect the folding of the airbag 20 as described herein. A control monitor 166 is connected to the processor 90 and displays the status of each piston/cylinder unit, allows an operator to input commands for operating the various piston/cylinder units, and displays error codes. The monitor 166 is commercially available from General Electric and is designated the General Electric Panel View Monitor. The processor 90 is commercially available from General Electric and is designated the General Electric Controller Series 90/30.
In FIG. 11, the pivotable blade 102 is shown in its disengaged position prior to clamping a first portion 24a of the inflatable bag portion 24. Additionally, the folding blades 110c and 110f of the first folding mechanism 110 and the folding blades 120c and 120f of the second folding mechanism 120 are shown separated prior to grasping second and third portions 24b and 24c of the bag portion 24.
An operator places the can portion 22 on the upper plate 50b of the fixture 50a. The operator then actuates one of two switches 170, shown in FIG. 1, to cause the grippers 51 to grip opposing edge portions of the opening 22b to secure the can portion 22 in position prior to folding.
When the can portion 22 has been secured in position and the bag portion 24 is laying smooth and flat on the tables 32, 34, 36, 38, 40 and 42, the operator again actuates one of the two switches 170. Thereafter, the upper tooling 70 is rotated via the rotary actuator 147 approximately 90° from the position shown in FIG. 3. The carriage 60 is moved via the drive unit 63 to its first folding position, shown in FIG. 1, where the proximity switch 66a is positioned across from the pin 68a. The pivotable blade 102 is then moved to its "down" position to clamp the first portion 24a of the bag to the tables 32 and 34, see FIG. 12. Next, the folding blades 110c and 110f of the first folding mechanism 110 and the folding blades 120c and 120f of the second folding mechanism 120 are closed so as to grasp the second and third portions 24b and 24c of the bag portion 24.
After the folding blades 110c 110f, 120c and 120f have been closed, the plates 40a and 42a are moved horizontally out from between the folding blades 110c, 110f, 120c and 120f, see FIGS. 13 and 14. The plates 36a and 38a are lowered. Further, the first plate 50b of the fixture 50a and, hence, the can portion 22 of the airbag 20 are lowered via the piston/cylinder units 50f and 50g. The lowered position of the first plate 50b is detected by the sensor 50m. The lowering of the plates 36a and 38a also effects the lowering of the plates 32h and 34h via engagement of the lower surfaces of the plates 36a and 38a with the bars 33a, 33b and 35a, 35b, see FIG. 14.
Next, the folding blades 110c, 110f, 120c and 120f are rotated via rotary drive units 110b and 120b approximately 360° and simultaneously moved inwardly toward one another to create first folds in the bag portion 24, see FIGS. 15 and 16. The blades 110c, 110f, 120c and 120f move inwardly as a result of movement of the support plates 110a and 120a via the rodless cylinders 116 and 126.
After the first folds have been created in the airbag 20, the upper tooling 70 is lowered via the piston/cylinder unit 144 until the rubber stoppers 142d engage the partially folded bag portion 24, see FIG. 17. The rubber stoppers 142d serve to retain the first folds in the partially folded bag portion 24. As the upper tooling 70 is lowered, engagement pins 142c enter into corresponding openings (not shown) in the upper plate 50b of the fixture 50a.
After the first folds have been made and the upper tooling 70 has been lowered, the piston 152 remains in its extended position so that the stripper fingers 157a and 157b are in their "up" position. Further, the fold retaining piston/cylinder units 149 are not activated and, hence, their corresponding hold-down elements do not engage with the airbag 20.
Following the lowering of the upper tooling 70, the second blades 110f and 120f are moved upwardly away from their associated first blades 110c and 120c until they engage the stop block 103, which block 103 is shown in FIG. 2. The carriage 60 is then moved to its retracted position, where the sensor 66c is positioned directly across from the pin 68c. Thereafter, the plates 36a, 38a, 32h and 34h are returned to their "up" positions and the plates 40a and 42a are moved inwardly so as to be positioned adjacent to the plates 36a and 38a (see FIG. 17).
The following homing events occur after the carriage 60 has been moved to its retracted position. The first and second piston/cylinder units 119 and 129 are actuated causing their respective pistons 119a and 129a to extend outwardly. The folding mechanisms 110 and 120 are then moved apart from one another along the guide rails 112 and 114 via the rodless cylinders 116 and 126 until their respective stop members 118 and 128 engage with the pistons 119a and 129a. When this has occurred, the folding mechanisms 110 and 120 are positioned in their second folding positions. Thereafter, the second blades 110f and 120f separate an additional distance from their associated first blades 110c and 120c such that the blades 110c, 110f, 120c and 120f are positioned as shown in FIG. 18. The rotary drive units 110b and 120b rotate the folding blades 110c, 110f, 120c and 120f approximately 360° back to their initial positions. When the folding blades 110c , 110f, 120c and 120f are in their initial positions, flags 200a and 200b associated with the blades 110c and 120c are positioned across from and sensed by sensors 202a and 202b, see FIG. 1. The pivotable blade 102 is moved to its "up" position, shown in phantom in FIG. 2.
Also while the carriage 60 is in its retracted position, the rotary actuator 147 of the upper tooling 70 is vented to atmosphere and the rotary drive unit 50h is activated to rotate the fixture 50a and, hence, the upper tooling 70 and the can portion 22 approximately 90°, see FIG. 18. After being rotated approximately 90°, the can portion 22 is positioned in its second folding position, which is sensed via the sensor 50k.
With the can portion 22 and the first and second folding mechanisms 110 and 120 positioned in their second folding positions, the carriage 60 is moved forward to its second folding position where the sensor 66b is positioned across from the pin 68b. Thereafter, the pivotable blade 102 is moved to its "down" position to clamp a middle portion of the partially folded bag portion 24 to the tables 32 and 34, see FIG. 19. The folding blades 110c and 110f of the first folding mechanism 110 and the folding blades 120c and 120f of the second folding mechanism 120 are then closed to grasp opposing end portions of the partially folded bag portion 24.
After the folding blades 110c, 110f, 120c and 120f have been closed, the upper tooling 70 is raised. The plates 40a and 42a are moved horizontally out from between the folding blades 110c, 110f, 120c and 120f. The plates 36a, 38a, 32h and 34h are also lowered. The folding blades 110c, 110f, 120c and 120f are then rotated via the rotary drive units 110b and 120b approximately 360° and simultaneously moved inwardly toward one another to create second folds in the partially folded bag portion 24 to form a completely folded airbag 20. The completely folded airbag 20 is shown in FIG. 20. The blades 110c, 110f, 120c and 120f move inwardly as a result of movement of the support plates 110a and 120a via the rodless cylinders 116 and 126.
After the second folds have been created in the airbag 20, the upper tooling 70 is lowered via the piston/cylinder unit 144 until the engagement pins 142c enter into the corresponding openings (not shown) in the upper plate 50b of the fixture 50a. The piston 152 is then moved to its retracted position so that the stripper fingers 157a and 157b move downwardly and pass through the slot 102a in the blade 102. The stripper finger 157a also engages slots 121 in the blades 120c and 120f while the stripper finger 157b engages slots 111 in the blades 110c and 110f. Also, the fold retaining piston/cylinder units 149 are activated causing their hold-down elements 142d to engage the folded bag portion 24.
After the upper tooling 70 has been lowered, the second blades 110f and 120f are move upwardly away from their associated first blades 110c and 120c until they engage the stop block 103. The carriage 60 is then moved to its retracted position. As the carriage 60 is retracted, the bag portion 24 is prevented from moving with the blades 110c, 110f, 120c and 120f via the stripper fingers 157a and 157b. After the carriage 60 has been retracted, the plates 36a, 38a, 32h and 34h are returned to their "up" positions and the plates 40a and 42a are moved horizontally to their home positions adjacent to the plates 36a and 38a. Also, the operator grips the folded airbag 20 and activates one of the two switches 170, causing the upper tooling 70 to rise. The completely folded airbag 20 is then removed by the operator.
After the carriage moves to its retracted position, the piston/cylinder units 119 and 129 are deactivated, the first and second folding mechanisms 110 and 120 return to their initial positions shown in FIG. 1, the second blades 110f and 120f separate an additional distance from their associated first blades 110c and 120c (see FIG. 11), the rotary drive units 110b and 120b rotate the folding blades 110c, 110f, 120c and 120f to their initial positions, the pivotable blade 102 is moved to its "up" position, and the first plate 50b of the fixture 50a returns to its "up" position.
Having described the invention in detail and by reference to preferred embodiments thereof, it will be apparent that modifications and variations are possible without departing from the scope of the invention as defined in the appended claims. | An apparatus is provided for folding an airbag. The apparatus includes tables for supporting the airbag. A securement mechanism is associated with the tables and secures the airbag in position relative to the tables. A carriage is provided and is movable towards and away from the tables. A clamping mechanism is associated with the carriage and clamps a first portion of the airbag to the tables. First and second sets of folding blades are also associated with the carriage. The first and second sets of folding blades grasp second and third portions of the airbag and create first folds in the airbag to form a partially folded airbag. An engagement mechanism engages the partially folded airbag to maintain the first folds in the partially folded airbag. The securement mechanism further rotates the engaged partially folded airbag about a vertical axis. The first and second sets of folding blades additionally grasp opposing portions of the partially folded airbag to create second folds in the partially folded airbag to form a completely folded airbag. | 1 |
BACKGROUND OF THE INVENTION
The invention relates to a device for welding overlapping foil edges with a heater, with contact rollers for the exterior contact at the foil edges as well as at least one height adjustment device, whereby the height adjustment device has a guide device for movement control of the respective contact roller essentially transversely to the processing direction of the foil edges, as well as a drive for moving this contact roller.
Devices for the overlapping welding of foil edges are described in DE-OS 35 35 759, DE-OS 40 00 017, and DE-GM 88 16 287.7. The devices are used particularly for welding foils in waste dump construction. Hereby high requirements are posed on the quality of the welding.
During the welding of the foil edges, the device drives along the two edges of the foils, whereby the foil edges are arranged so as to be overlapping. In the process, the foil edges enter the device on top of each other and are then guided over a heater which as a rule is constructed in a wedge-shape. This wedge-shaped heater is arranged lying down, i.e. the two partial surfaces which converge backwards toward the wedge tip are positioned on top of each other. Hereby the heater is oriented with its obtuse end toward the entrance of the foil edges into the device.
Each wedge surface of the heater may be divided into two partial wedge surfaces which are arranged at a distance from each other and between which a groove extends. The top foil edge is hereby passed over the two top partial wedge surfaces and the bottom foil edge is passed over the two bottom partial wedge surfaces. Both of the respective superposed partial wedge surfaces combine toward the back, forming a line-shaped wedge tip where the two foil edges are brought together.
The heater has several heating elements which ensure heating of the wedge surfaces which function as heating surfaces. Hereby the heating plasticizes the foil edges in the area of the partial wedge surfaces in such a way that they are welded together after being brought together, resulting, in particular due to the partial wedge surfaces which are arranged at a distance from each other, in two weld seams which extend parallel to each other at a corresponding distance. Between the weld seams a channel is formed which, in order to test the tightness of the weld seams, is closed off at one end, whereupon air is introduced into its other end. If there is no leaking of air during this test, the weld seams are correct.
In order that the foil edges are guided past the heating surfaces of the heater with contact, and in particular are then passed together with the pressure required for welding, contact rollers have been provided in the heater area itself and behind the heater, i.e. one contact roller for each of the two parallel weld seams. If the contact rollers are located behind the heater, two contact rollers are arranged on top of each other in order to be able to exert pressure from both sides on the corresponding heated areas of the foil edges. One pair each of the contact rollers behind the heater simultaneously function as drive rollers, i.e. at least one of the rollers is equipped with a drive which pulls the foil edges into the device and hereby drives the device forward.
In the devices according to DE-OS 35 35 759 and German OS 40 00 017 contact rollers are suspended on plate springs which press them with a preload against the heater or against a stationary contact roller facing it. There is no height adjustment device to adapt the device to different thicknesses of the foil edges. But a height adjustment device is found in the device according to DE-GM 88 16 287.7. It consists of a pneumatic cylinder whose piston rod acts directly on one of two opposing contact rollers. Hereby the contact roller movement is essentially guided transversely to the processing direction of the foil edges by the pneumatic cylinder, i.e. via the guiding of its piston and piston rod.
Such a height adjustment device on the one hand presupposes the existence of a source of compressed air. This significantly restricts the application of the device. Especially in the waste dump field where the device is used primarily, compressed air sources are frequently not available. Another disadvantage is that no gap between the two contact rollers or between one contact roller and the heater can be set, which makes it difficult to generate reproducible pressure conditions. However, the quality of the weld seams when connecting two foil edges also depends essentially on the contact pressure generated by the contact rollers. Finally, with the pressures occurring here, the pneumatic cylinders have a tendency to jam the piston rod in the cylinder.
SUMMARY OF THE INVENTION
The invention is based on the task of constructing the height adjustment device in a device of the initially cited type in such a way that the movement of the respective contact roller is guided flawlessly.
According to the invention this task is solved in that the drive comprises a spindle which may be rotated by a torque motor and which is connected via a spindle nut to the contact roller and is positioned so that it may slide axially, whereby the spindle is supported at a spring device in such a way that the contact roller is spring-mounted in the direction facing away from the foil edges.
According to the invention, the height adjustment device uses a spindle driven by a torque motor, e.g. an electric motor, which is able to slide axially, but is supported in this direction by a spring device. With this spindle the respective contact roller may be adjusted essentially transversely to the processing direction of the foil edges, whereby the spindle permits a very accurate adjustment of the free gap for the passage of the foil edge(s). In this way the device may be set to the appropriate thickness even prior to the pulling in of the foil edges, a process which may be reproduced at any time. The spring-mounted axial support of the spindle ensures that no impermissible stresses or obstructions occur during the passage of the foil edges, especially if the foil edges fluctuate in their thicknesses, are profiled, or carry dirt, e.g. rocks pressed into them. The respective contact roller is then able to yield against the effect of the spring device by widening the gap and then springs back into the intended position. The invented separation of the adjustment of the contact roller and spring-mounting to the extent that the same spring effect is always present in each position of the contact roller therefore has significant advantages.
Execution of the invention provides that the torque motor is kept stationary in the device and is connected to the spindle via a sliding coupling.
According to another characteristic of the invention it is proposed that the spindle nut or an additional spindle nut is supported at the device by a support element against transverse forces which act on the spindle. This support eliminates possible bending forces from the spindle, so that the spindle no longer needs to absorb them and therefore may be of light construction. The support element may be constructed as a support strut coupled to the device, whereby the spindle then should be able to slightly swivel. As an alternate, the support element is constructed in the form of at least one support roller which runs on a guide track extending parallel to the spindle axis.
The invention furthermore provides that the spring device has at least one helical spring which surrounds a spindle extension and which supports itself on one side at the spindle and on the other side e.g. at the device case. It is also possible to provide spindle extensions surrounded by helical springs on both sides, e.g. to achieve a higher spring force. Hereby it is possible to provide steps for the helical springs which are arranged in such a manner that one of the helical springs contacts its corresponding stop only after the other helical spring has traveled a certain distance. In this way a gradually increasing spring force is obtained during the spring operation. It is preferred that the helical springs are supported on the bearing cases of the spindle which are present in any case.
According to the invention it is also proposed that the axis of the spindle extends parallel to the processing direction of the foil edges and the spindle nut is connected via a connecting rod to the contact roller. This construction is particularly space-saving and permits sensitive adjustment of the contact roller. Hereby the connecting rod should be constructed as a connecting bow which borders the contact roller on both sides. It is useful that the connecting rod extends from the contact roller at an angle in the spring direction of the spring device to the spindle nut.
Various possibilities exist for constructing the guide device for the respective contact roller. Especially simple is the construction as a swiveling guide rod, whereby the extent of the invention includes spanning of the respective contact roller by two guide rods. It is useful that the guide rod extends essentially parallel to the processing direction of the foil edges so that the swivel movement of the contact roller takes place essentially vertically.
The height adjustment device according to the invention is particularly suitable for the paired, superposed contact rollers behind the heater. Hereby it is sufficient if only one contact roller of a pair of contact rollers is equipped with a height adjustment device according to the invention, i.e. preferably the respective top contact roller.
BRIEF DESCRIPTION OF THE DRAWINGS
The drawings show the invention in more detail, using an embodiment.
FIG. (1) shows a lateral view of the invented device;
FIG. (2) shows a rear view of the device according to FIG. 1;
FIG. (3) shows a cross-section through the device according to FIGS. 1 and 2 in plane A--A (FIG. 1);
FIG. (4) shows a partial view of a contact roller pair of the device according to FIGS. 1 to 3 in a partial section; and
FIG. (5) shows a frontal view of a contact roller of the device according to FIGS. 1 to 3 in a partial section.
DETAILED DESCRIPTION OF THE INVENTION
The device (1) shown in FIGS. (1) to (3) comprises a carriage (2) with two drive axles (3,4) which in the area of the front ends carry two wheels (5) and in the area of the rear end carry a roller (6). The device (1) may be driven in the direction of arrow A (FIG. 1).
The carriage (2), i.e. the area of the front end, holds a carrier (7) which is shaped--as is seen especially from FIGS. (2) and (3)--in such a way that it forms in the bottom area an insertion slot (8) which is open toward one side and in the top area an insertion slot (9) which is open toward the other side. Naturally, the insertion slots (8,9) are also open toward the front and back.
A carrier plate (10) is attached to the front wall of the carrier (7) which projects upward and at whose top end is attached a horizontal case plate (11) which extends over the entire width of the device (1).
A heater (13) is attached to the back end of the carrier (7) via a support rod (12). This heater has a top heating surface (14) and a bottom heating surface (15) which extend backwards at an angle and meet at a wedge tip (16). Hereby the heating surfaces (14,15) may also be divided transversely to the longitudinal axis of the device (1) (see DE-OS 35 35 759)--as is common in such devices in order to produce two parallel weld seams spaced at an interval to each other. The heater (13) here has heating rods which are not shown in detail here and which ensure heating of the heating surfaces (14,15). The possible arrangement of the heating rods and their control are found in DE-OS 40 00 017 and DE-OS 35 35 759.
Behind the wedge tip (16) of the heater (13), a top contact roller (17) and--facing it--two bottom contact rollers (18,19) are located. The top contact roller (17) is equipped with two circumferential sets of gear teeth (20,21) spaced at a distance from each other, while the bottom contact rollers (18,19) each carry a frontal set of gear teeth (22,23). The gear teeth sets (20,21,22,23) have approximately the same width and face each other correspondingly (FIG. 2).
The top contact roller (17) is positioned on a roller rotation axis (24) which is held at the back ends by two longitudinal connecting rods (25, 26) which extend essentially horizontally forward. The longitudinal connecting rods (25, 26) are positioned at the carrier (7) in such a way that they are able to swivel. In addition, a U-shaped support bow (27) engages with the roller rotation axis (24), i.e. on both sides of the contact roller (17). It is shown particularly in FIG. (1) that the support bow (27) extends in the shown position at an angle toward the top and spans on both sides a spindle nut which is not visible here and which is positioned on a spindle (28) which extends horizontally and in the longitudinal direction of the device (1). On both sides of the spindle nut, guide rollers (29) which are supported on the underside of the case plate (11) are positioned on the support bow (27).
The spindle (28) is positioned in the front and back rotatably and axially sliding in bearing plates (30,31) which are attached to the case plate (11). The spindle ends in front of the front bearing plate (30) in a coupling case (32) to which the spindle (28) is connected in a rotation-proof manner. The coupling case (32) does have two facing longitudinal slots (33) which engage in a form-fitting manner with a crossbar (34) which is held in a drive shaft (35). The drive shaft (35) may be rotated by an electric motor which is not shown here in detail. It is also held axially in a stationary manner.
The spindle (28) has a threaded section (36) on which the spindle nut located on the support bow (27) is positioned. In the area of the front end of the threaded section (36) a stop plate (37) is positioned on the spindle (28) and is fixed to this spindle (28). A helical spring (39) surrounding the spindle (28) is supported between this stop plate (37) and the front bearing plate (30).
The back end of the spindle (28) reaches through the rear bearing plate (31) and projects toward the back. It also has a stop plate (40) which is fixed to it at its free end. Between this stop plate (40) and the rear bearing plate (31) there is another helical spring (41) which also surrounds the spindle (28), but which is shorter than the distance between stop plate (40) and bearing plate (31). In this way, the helical spring (41) is only actuated after the first helical spring (39) has already been compressed by the differential length between the above mentioned distance and the length of the second helical spring (41), and in this manner the spring force is increased.
The bottom contact rollers (18,19) are positioned--as may be seen especially in FIG. (4)--on a roller rotation axis (42) which in the center between the two contact rollers (18,19) is kept in a bearing (43) which is located in a bearing bracket (44) connected tightly to the carriage (2). The bearing (43) not only permits rotation of the roller rotation axis (42) but also a swiveling of the roller rotation axis (42) about a swiveling axis (in FIG. 4 vertical to the drawing plane) which extends vertically in relation to it and horizontally, i.e. respectively toward both sides by the angle a drawn in FIG. (4). On the outside, the roller rotation axis (42) is guided in retainers (46,47) in such a manner that the roller rotation axis (42) is able to perform a vertical movement inside the retainers, but not a horizontal movement. Thus the movement of the roller rotation axis (42) is limited to the swiveling about the above mentioned swiveling axis--in addition to the rotation movement.
The contact rollers (18,19) are positioned on the roller rotation axis (42) with the same bearings (48) as those in the bearing bracket (44). The contact rollers (18,19) thus are able also to execute a swivel movement relative to the roller rotation axis (42), in particular by the angle a, drawn in FIG. (4), toward both sides, i.e. about a swivel axis extending vertically to the roller rotation axis (42) and horizontally (in FIG. (4) vertical to the drawing plane). In this way the contact rollers (18,19) may adjust themselves so that they are at different heights but nevertheless have parallel rotation axes.
In addition to the contact rollers (17,18,19) the device (1) also has drive rollers. For reasons of clarity they have not been shown here and are located behind--in FIG. (1) to the left of--the contact rollers (17,18,19). At least one of the drive rollers is coupled with an electric drive motor.
A total of eight contact rollers (49,50,51, 52, 53,54)--only six of these are shown in the drawings--also are arranged above and below the heating surfaces (14,15) of the heater (13). Two each contact rollers (49,50) or (50,51) or (53) or (54) are positioned consecutively in a bearing bridge (55,56,57,58) extending longitudinally in such a way that the respective frontal contact rollers (49,51) are located in the area of the horizontal sections of the heating surfaces (14,15), while the respective rear contact rollers (50,52,53,54) are located in the area of the wedge sections of the heating surfaces (14,15) so that the line of the bearing bridges (55,56,57,58) is bent. Two each bearing bridges (55,57) or (56,58) are arranged adjacently, whereby the distance between them corresponds approximately to the distance between the bottom contact rollers (18,19) or the circumferential gear tooth sets (20,21).
The bearing bridges (55,56,57,58) are attached to plate springs (59,60,61,62) which extend forward and at this point are tightly clamped into the carrier (7). The bearing bridges (55,56,57,58) thus each are subject to a preload of the plate springs (59,60,61,62) directed toward the heater (13), whereby the plate springs (59,60,61,61) also permit a swiveling of the bearing bridges (55,56,57,58) about an axis extending transversely to the longitudinal axis of device (1) and horizontally.
The adaptability of the contact rollers (49,50,51,52,53,54) is further increased by the fact that they may be swiveled similar to the bottom contact rollers (18,19) about a swivel axis which extends horizontally in the longitudinal direction of the device (1). This is seen from the view according to FIG. (5) which shows a partial cross-section of the contact roller (50). The contact roller (50) is positioned on a roller rotation axis (64) by way of a bearing (63), whereby the bearing is constructed in a bowl shape in such a way that it permits the previously mentioned swiveling (in FIG. 5 about an axis vertical to the drawing plane), so that the contact roller (50) may take an angled position relative to the roller rotation axis (64). The roller rotation axis (64) is held in the bearing bridge (55) which has a U-shaped cross-section. The other contact rollers (49,51,52,53,54) are positioned in the same manner.
The device (1) described above functions as follows when welding two overlapping foil edges. The device (1) is driven forward by the above-mentioned drive roller which are not shown in detail and which support themselves on the already welded foil edges. Hereby the foil edges enter into insertion slots (8,9) and then glide over the heating surfaces (14,15) of the heater (13). They are pressed by the contact rollers (49,50,51,52,53,54) onto the heating surfaces (14,15), whereby the contact rollers (49,50,51,52,53,54) are able to adapt to the surfaces of the foil edges. The heater (13) heats the foil edges on their facing sides to welding temperature. They are then passed over the wedge tip (16) into the area of the top and bottom contact rollers (17,18,19).
Compared to the position shown in FIG. 1, the latter have been positioned in such a way that the two foil edges are pressed onto each other with the required force. For this reason the spindle (28) has been set into rotation via the coupling case (32), the drive shaft (35), and the electric motor (not shown), in such a way that the support bow (27) has been moved backwards via the spindle nut. Because of the given kinematics, this movement of the spindle nut results in a swiveling of the longitudinal connecting rods (25,26) and thus of the top contact roller (17) downwards in the direction toward the bottom contact rollers (18,19). The gap between the top contact roller (17) and bottom contact rollers (18,19) may hereby be set precisely via the spindle (28).
To the extent that the foil edges have irregularities or carry pressed-in projecting rocks, the top contact roller (17) is able to yield resiliently. The yielding movement is transferred via the support bow (27) and the spindle nut to the spindle (28) and presses the latter forward. During this process, it supports itself via the stop plates (37,40) on the helical springs (39,41), i.e. the movement is absorbed resiliently. The form-fitting between spindle (28) and drive shaft (35) is not lost in the process, since the longitudinal slots (33) permit an axial movement of the spindle (28) in this direction. In order to prevent vertical forces from acting on the spindle (28), the support bow (27) supports itself via guide rollers (29) on the underside of the case plate (11).
In addition, the bottom contact rollers (18,19) are able to adapt their position to the irregularities of the foil edges in such a way that the pressure stress on the foil edges nevertheless remains as constant as possible. | The invention relates to a device for welding overlapping foil edges with a heater, with contact rollers for the exterior contact at the foil edges as well as at least one height adjustment device, whereby the height adjustment device has a guide device for movement control of the respective contact roller essentially transversely to the processing direction of the foil edges, as well as a drive for moving the contact roller. | 1 |
BACKGROUND OF THE INVENTION
Acoustic resistances made of woven or etched mesh or screen are well known in the art. In such materials, the apertures can be made small, a condition necessary to produce acoustic impedances in which dissipative, resistance parameter substantially exceeds the reactive inertance parameter. Common in the prior art, the etched mesh or screen is cemented or clamped over an aperture to obtain an acoustic impedance having a relatively pre-determined value.
When metal screens or perforate mesh are used, it is relatively simple and inexpensive to form and shape such materials into useful devices or plugs for insertion into acoustic apparatus. Such devices are relatively sturdy but if once distorted, it is difficult to restore the devices to their original shape.
Accordingly, it is a feature and purpose of this invention to provide acoustic devices that are durable and can be conveniently handled and cleaned, inserted and removed from their operational locations without damage to the device.
Other types of acoustic plugs comprise plastic or metal bushings having a hole of selected size to provide a desired degree of closure to modify the frequency response in accordance with the wearer's requirements.
However, it has been found that when a single hole, or even a few holes formed in a concentrated area, are used to obtain the resistance, the sound, in order to pass through these holes, must converge to this small area. This action contributes an inertance component to the impedance limiting the quality of the acoustic element as a resistive element. If holes are produced in a less concentrated area, such as over the surface of the mesh, the movement of air in the sound is not forced to store as much energy in inertia to converge to the holes that produce the frictional component of impedance, thereby providing the result that the inertance component of the impedance is lower and the acoustic element provides a better resistance.
Also, if high intensity sound such as would occur at the outlet of a receiver is channeled through a single hole, or even through a few holes, there is a tendency for unwanted turbulence to develop.
Accordingly, it is another feature and purpose of the present invention to provide an acoustic plug which provides a selected acoustic impedance while developing no disruptive turbulence.
The foregoing and other features and advantages of the invention will be apparent from the following more particular description as illustrated in the accompanying drawings wherein:
DESCRIPTION OF THE DRAWINGS
FIG. 1 is an isometric view of a microphone transducer mounted in an eye-glass type of hearing aid and showing an acoustic element in accordance with the invention mounted in an inlet opening to the microphone;
FIG. 2 is an isometric view of a behind-the-ear type of hearing aid showing a receiver transducer mounted in the hearing air and showing an acoustic resistance element mounted in the receiver output port leading through the acoustic channel to the ear cavity;
FIG. 3 is a relatively enlarged view of the inlet opening portion of FIG. 1 to better show the positioning of the acoustic element in accordance with the invention;
FIG. 4 is a view in cross section of an acoustic element in accordance with the invention which element has a mounting rim;
FIGS. 5A, 5B and 5C show an enlarged view of an acoustic element in accordance with the invention; more particularly FIG. 5A shows a mesh or screen in sheet form; FIG. 5B shows the acoustic element partially formed into its cylindrical construction; and FIG. 5C shows the acoustic element fully formed for insertion in an associated opening;
FIG. 6 shows another embodiment of the present invention wherein the acoustic element is formed in a cylindrical shape with the closed end of the cylinder having a portion of the material doubled back to form a reinforced rim around the acoustical aperture area;
FIG. 7 shows an embodiment of the invention wherein the center portion of the mesh or screen is fused together to thereby provide a selected acoustic resistance to sound passing through the screen; and,
FIG. 8 is another embodiment of the invention showing a fused pattern on the mesh screen which pattern is formed to provide an exact desired acoustic resistance.
DESCRIPTION OF THE INVENTION
The present invention is directed to a damping element formed essentially in a cup-like or closed cylindrical form having the end of the cylinder formed as a mesh or matrix material which allows sound to pass therethrough. The acoustic resistance provided by said mesh to sound passing therethrough is selectively controlled to provide a desired dissipative resistance parameter. Because of the flexible nature of the materials used, the inventive acoustic element, if deformed, may be easily restored to its original shape such as by inserting the element over a mandrel. Thus, the inventive acoustic element may be shipped, inserted, removed, handled and cleaned without impairing its performance when it is reinserted in its operating position.
FIG. 1 shows one example wherein the inventive acoustic element 31 may be used. In FIG. 1 an eyeglass type of hearing aid assembly 10 includes a microphone 11, suitably mounted as by isolator mountings 13 and 15 within a chamber 17 formed in the temple piece 19 of the eyeglass. A sound opening 21 in the wall of the chamber 17 couples sound to a sound duct 23 of microphone 11.
An acoustic resistance element or plug 31 in accordance with the invention, may be located or positioned in the sound duct 23. As is known, acoustic element 31 provides a selected acoustic resistance to sound passing through duct 23.
Another example of a usuage of the present invention is shown in FIG. 2 which depicts a behing-the-ear type of hearing aid assembly 33 including a receiver 37 mounted within a housing 35. As is known, sound is conveyed from the output of the receiver 37 through a sound channel or duct 39. A flexible tubing 40 and a suitable ear mold 41 couple the sound duct 39 to the ear cavity of the user. An acoustic element 31 in accordance with the invention, may, for example, be mounted at the outlet of the receiver 37 at the point which receiver connects to a channel 39, or at the end of channel 39 where it connects to the flexible tubing 40.
FIG. 3 is a relatively enlarged view showing the acoustic resistance element 31 positioned in sound duct 23. Note also that acoustic element 31 could be mounted in a relatively reverse orientation in FIG. 3. FIG. 4 shows an embodiment of the acoustic element 31 having an end rim or shoulder 32 which can abut the end of the sound duct 23 for positioning element 31 therein.
Refer now to FIGS. 5A, 5B and 5C for purposes of describing the structure of the acoustic resistance element 31 in accordance with the invention. The acoustic resistance element 31 comprises a woven mesh or matrix having fibers 53 of appropriate diameter and spacing. FIG. 5A shows sheet 31C from which the acoustic resistance element is formed. Sheet 31C may be of a thermoplastic material such as nylon or polyester, or a disolvable material such as acetate or rayon. As shown in FIG. 5B, the sheet 31C is folded into a cup-like member 31B having one end 31E capped or covered. Next, the sides or walls 31D of the cup-like member 31B are fused to form a less pervious sound wall or barrier, as shown in FIG. 5C. The end or aperture area 31E of the cup-like member comprises the effective acoustic resistance.
FIG. 6 shows an embodiment of the acoustic resistance element 31 in accordance with the invention wherein the material around the end 31E of the cup is doubled back to form a reinforced rim 31F; and, also to provide a better definition of the aperture area through which sound is to pass. The rim 31F can be formed by fusing the outside wall sections by heat, or by a solvent, while protecting or properly shielding the aperture area.
FIG. 7 shows another useful embodiment of the invention which will now be described.
Since it is not always feasible to obtain fiber materials having the exact fiber diameter and spacing to achieve the desired acoustic resistance, the structure of FIG. 7 is a means of increasing the effective acoustic resistance of the acoustic element 31. The overall impedance to sound passing through the mesh or matrix can be increased by fusing portions of the aperture area 31E such as at 31G. In FIG. 7, the size or area of the fused portion 31G determines the increase in acoustical resistance. By fusing the central portion of the area, the total area of the aperture available for passage of sound is effectively decreased thereby increasing the impedance of the acoustical element while yet obtaining a minimum addition to the inertance component of the impedance as the sound is refracted around the sealed-off area.
FIG. 8 shows another embodiment of the invention in which the aperture portion 31E has a pattern 31G1 formed thereon in accordance with a selected acoustical resistance required. More specifically, a fusing action is provided to the mesh or matrix 31E concurrently or alternatively as the acoustic resistance of the mesh 31E is being monitored. When the monitored acoustic resistance equals a desired total resistance, the fusing action is terminated.
In various prior art devices, in order to obtain an increased acoustic resistance, sound was caused to pass through a narrow hole or constriction. A principle feature of the present invention is that maximum use is made of the entire aperture area for sound flow. As mentioned above, the use of the entire aperture area for sound flow provides an acoustic impedance element wherein the inertance component of the impedance is lower and the acoustic element provides a better resistance; and also, for sound of high intensity the acoustic turbulence and noise is thereby minimized.
The inventive acoustic resistance element 31 can be crushed or collapsed without serious damage, and it can easily be restored to its original shape by unfolding the collapsed element, or by inserting the collapsed element over a mandrel and reforming it to its initial cup-like shape. The acoustic resistance element of the invention thus provides a removable, crush proof element which provides a selected acoustic resistance.
The invention has been particularly shown and described with reference to preferred embodiments and the claims define the scope thereof. | A damping element comprising fiberous fuseable material shaped to form a cup-like member which may be inserted in the sound openings of an acoustic transducer to provide a selected acoustic resistance. | 7 |
CROSS REFERENCE TO RELATED APPLICATIONS
This application is a continuation-in-part of U.S. Ser. No. 08/879,107, filed Jun. 19, 1997, abandoned, the contents of which is herein incorporated by reference.
FIELD OF THE INVENTION
This invention is related to the field of plastic molding, particularly to a high pressure injection molding machine which requires no externally applied clamping pressure, and additionally to a multiple mold workstation module comprising a single extrusion machine and hydraulic pumping station coupled to individual mold workstations each having an independent injection unit and mold clamp.
BACKGROUND OF THE INVENTION
High pressure injection molding devices, e.g. those devices operating at injection pressures of greater than 1000 psi, are well-known in the art for their use in producing plastic components. In a conventional injection molding machine, a mold sized for the machine must be properly positioned in order to receive plastic through a high temperature/pressure injection process. In this manner, the mold is placed within the machine by first opening a mold clamp section wherein the mold can be mounted to a front platen of the machine. This mounting is usually performed by the use of clamps bolted to some, of the many, threaded holes in the platen. The back half of the clamp section must also be set, which is a complicated adjustment, for the clamp section must be firm but not too tight if proper plastic flow is expected. Knock-out bars, referred to as ejectors, must also be adjusted for ejection of the finished parts. The ejectors are positioned for proper length of travel to eject the finished parts. It is critical that the ejectors do not over travel, or mold damage will occur. When the adjustment is complete, the clamp section is closed to secure the back half of the mold to the rear platen, again typically with clamps. The mold may then be cycled open and closed to permit ejector and clamp pressure adjustment. Upon positioning of the movable portion of the mold to its mating position with the stationary mold half, sufficient clamping pressure must be externally applied and maintained during high pressure injection to prevent flashing of molten plastic from the mold interface, and to prevent warpage during the cool-down and shrinkage phase, prior to ejection of the parts. Maintenance of the required clamping pressure is normally maintained by applying sufficient external force, e.g. via the use of a hydraulically powered ram, so as to oppose the internal pressures developed within the mold cavity during injection. Mold speed is set to occur within a cycle specified.
Heater zones must be turned on, usually three to six, depending on the machine size. Temperatures must be set according to the plastic material being used wherein variations run from 300 degrees Fahrenheit to 700 degrees Fahrenheit. If the temperature is too hot, the plastic will burn, and if it is too cold, damage to the machine will likely occur. The controllers on the machine regulate and maintain set temperatures within a very close range at a very considerable cost. While a machine is heated up, water lines on the mold are installed and tested for leaks.
Once all heat zones are stabilized, the injection unit is retracted from the mold area and materials added to the hopper. Molten plastic is then extruded from the nozzle to remove contaminated plastic that was used previously in the machine. This can be time consuming and materially wasteful, the amount of wasted material varies dependent upon the specific type of plastic and color of plastic selected. For example, if the machine previously had black color, and the new material is clear, it is not uncommon to use up to 100 pounds of plastic prior to making the first acceptable molding.
In operation, a shot size is determined and set, usually by moving limit switches located on the rear of the injection unit. Too much plastic will make the mold flash open, and too little will cause ejection problems. Estimates can be problematic, owing to the discrepancies caused by other variables such as pressure, temperature of the plastic, and back pressure. If the weight of the part to be formed is known, air shots can be made and weighed, otherwise the operation is guesswork. Once the settings are made manually, the machine timers must be set for a semi-automatic or automatic cycle. This requires trial and error but in either event, a trained set-up man can still spend several hours getting a machine on cycle, making acceptable parts, and still the operator can change any number of controls in seconds to make inferior parts that are not immediately identified.
The above complications are multiplied when additional molds are used. For instance, if ten molding machines are employed, the above set-up must be repeated ten times. In addition, when one mold machine is being set-up or serviced, the plastic is allowed to stagnate, if not cool, causing the malfunction of the plastic feeder and/or injector system. This non-operation can cause problems in and of itself.
What is lacking in the art is a compact high pressure injection molding device of simplified design, which maintains nominal pressure upon the mold cavity, prior to and during high pressure injection molding, while eliminating the need for additional means for generating and/or maintaining externally applied clamping pressure forces, e.g. hydraulic rams and the like; and wherein all process functions are commonly controlled from a single source.
SUMMARY OF THE INVENTION
The instant invention teaches a single or multi-mold high pressure injection molding device including a single extrusion machine and a single hydraulic system coupled to one or more independent mold workstations. Each mold workstation consists of an injection means including a resin accumulator for receipt of a particular volume of molten softened plastic, and which employs a source of hydraulic pressure to increase the pressure of the transferred softened plastic derived from the extrusion machine for subsequent high pressure injection into the workstation mold, which is of a split mold design. The injection units are coupled to the extrusion machine by a heated manifold having heated coupling lines. The hydraulic system provides fluid to each workstation via a single pumping station preset to a given pressure and controlled by variable displacement pumps and hydraulic accumulators.
The resin accumulator which supplies molten plastic to the injection unit employs a hydraulically driven piston having a step-down reduction chamber to increase the injection pressure of the molten plastic. The injection unit provides for high pressure passage of the plastic which allows the plastic to be transferred at lower temperatures. The injection unit has thermocouples to monitor the plastic temperature and a nozzle shut-off to regulate plastic flow. A series of heated check valves prevent the back-flow of plastic through the injection unit, manifold and extrusion machine.
Each mold workstation includes a split mold positioned between two plates, one movable and one stationary, which are mechanically linked via cylindrical tiebars. In a particular embodiment, a moving plate having half of the mold coupled to it, is in slidable engagement with the tiebars and is mechanically coupled to one or more relatively small hydraulic cylinders for effecting opening and closing of the mold. Upon initial closing, one or more piston actuators secured to the rear side surface of the moving plate operate slidable wedge shaped securement devices which are forced between reciprocally angled wear plates located on the rear side surface of the moving plate and the distal end of the tiebars, to provide final lockup. The slidable wedge shaped securement devices are particularly designed so as to partially encircle the tiebars when in the final lockup position, so as to provide over-center positioning of the wedge shaped securement device with respect to the longitudinal axis of the tiebar. The tiebars each have a threaded portion and a keyway allowing an adjustment nut to position the slidable wedges into an appropriate spatial locking position, while preventing rotation of said wedges about the tiebar. Movement of the securement devices causes the moving plate to lock against the fixed plate, whereby compressive forces are generated upon the mold halves, in an amount effective to maintain said mold halves within nominal position, during high pressure injection molding conditions, so as to prevent flashing from the mold, and without incurring warpage as the plastic cools. The necessary compressive forces for maintaining this nominal positioning of the mold halves, under high pressure injection molding conditions, derives from appropriately sizing the tiebars, such that the length, thickness and type of steel result in an elastic modulus which maintains the stretch or creep of the tiebar within a range effective to insure successful molding conditions. The adjustment nut further allows the use of various sized molds and accommodates ongoing wear of the wear plates.
In a second embodiment, a moving plate having half of the mold coupled to it is operated by a hydraulic piston coupled to an over-center hinge member. The hinge member maintains the mold in a closed position by positioning the hinge arms in a parallel, or near parallel position. The piston provides a high pressure actuator to maintain the mold in a fixed position. Mold separation is made possible by movement of the hinge arms.
The mold workstation further employs ejectors that protrude into the forming chamber when the mold is opened. The ejectors cause the finished product to be expelled from the mold and can be either operated by a hydraulic piston, or operated in the form of ejector fingers that extend through the mold when the mold is opened.
The initial cost, and operating costs, of a multi-mold workstation “module” becomes a fraction of the cost of multiple free operating adjustable machines. One extrusion machine can supply molted plastic to multiple injection units, e.g. ten or more, by use of a heated manifold whereby an economy of scale is achieved. Each injection unit employs a hydraulic actuated piston having a step down chamber reduction to increase the plastic pressure. The injection unit is cycled to accept a preset amount of plastic through the manifold system. The piston is then actuated to force the plastic at a high pressure into the mold. The injection unit has thermocouples to monitor the plastic temperature and a nozzle shut-off to regulate plastic flow. A series of heated check valves prevents the back-flow of plastic through the injection unit, manifold and extrusion machine.
Controls for the multi-mold workstation are centrally located allowing operation of each injector unit and mold machine from a single location. However, since the individual workstations utilize valves that perform all of the various functions, a plug-in connector could be in series with the wiring allowing the mold set-up person to plug in a portable control box and manually run any function prior to switching on automatic control.
The single extruder minimizes energy costs, as only two to three motors run constantly at independent load versus 20 to 60 motors on conventional machines of the same size. In addition, one raw material feeder, versus e.g. 10 raw material feeders, reduces spillage of pellets and lessens the chance of contaminating the material.
Accordingly it is an objective of the instant invention to teach an improved high pressure injection molding machine having a unique mold locking assembly which eliminates the necessity for application of clamping pressure during high pressure injection.
It is another objective of the invention to reduce the controls of a mold machine by 80 to 90 percent over typical production machines. The lack of adjustable controls decreases cost and increases reliability of operation.
Still a further objective of the invention is to teach a system wherein the power requirements are reduced by more than half of typical production machines.
Yet another objective of the invention is to teach the reduction of the workstation size and footprint so as to be less than half that of a typical production machine.
Yet a further objective of the instant invention is to provide the quality and product repeatability heretofore only obtainable in a single injection unit in a multi-mold system.
An additional objective of the invention is to teach the use of a mold workstation having slidable securement locks that are adjustable to the size of a mold and to accommodate wear.
Still an additional objective is to reduce the noise levels of a mold system by providing a system wherein motors and pumps are remote and reduced in size.
Additionally, a further objective is to reduce localized wiring to low voltage and eliminate high voltage motors at the individual workstations for increasing personnel safety.
Still another objective is to provide a single hydraulic system to feed multiple workstations which eliminates the need for multiple oil reservoirs thereby reducing costs, accidental spills, leaks and floor space.
Further still, an objective of the instant invention is to teach the use of a single extrusion machine for coupling to multiple mold workstations by use of a heated manifold system.
Other objects and advantages of this invention will become apparent from the following description taken in conjunction with the accompanying drawings wherein are set forth, by way of illustration and example, certain embodiments of this invention. The drawings constitute a part of this specification and include exemplary embodiments of the present invention and illustrate various objects and features thereof.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a pictorial view of the multi-mold workstation with single extrusion machine and manifold of the instant invention;
FIG. 2 is a cross sectional view of the injector unit;
FIG. 2A is an enlarged cross sectional view of a heated check valve;
FIG. 3 is a top plane view of a mold machine having an alternative clamp design in a closed position;
FIG. 4 is a top plane view of a mold machine in an open position;
FIG. 5 is a top plane view of a mold machine having a preferred clamp design in a closed position;
FIG. 6 is a rear plane view of a mold machine having the preferred clamp design;
FIG. 7 is a partial side view of a mold machine having the piston actuated wedge clamp;
FIG. 8 is a flow diagram of the hydraulic system; and
FIG. 9 is a pictorial view of a particular embodiment of a continuous extrusion injection molding system.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Although the invention will be described in terms of a specific embodiment, it will be readily apparent to those skilled in this art that various modifications, rearrangements and substitutions can be made without departing from the spirit of the invention. The scope of the invention is defined by the claims appended hereto.
Referring now to FIG. 1, set forth is a pictorial of the multiple mold workstation module of the instant invention. The module employs an extrusion unit 10 for use in feeding softened plastic through pipe 12 into a heated distribution manifold 14 . The heated distribution manifold 14 includes a collating hub 16 that allows for the even distribution of softened plastic to multiple mold workstations as depicted by numerals 18 - 27 . The illustrated and preferred quantity of mold workstations being between two and ten workstations with individual injection units forming the workstation module.
The distribution manifold 14 carries the plastic to the mold workstations through coupling pipe 30 having heater bands 20 positioned along the length of the pipe 30 for maintaining the plastic in a softened state during transfer. The coupling pipe 30 is secured to injector unit 100 , described in detail later in this specification, with directional flow check valve 108 to prohibit back flow of plastic into the manifold 14 . A valve 154 provides a shut-off between the mold workstation 184 and the manifold 14 and further allows for injection unit 100 detachment should the system require servicing. The removal of the mold workstation 18 does not inhibit operation of the extrusion machine 10 or injector unit 100 on other workstations.
For purposes of drawing clarity, the remaining coupling pipes are illustrated, but not numerated. Each coupling pipe operates in the above captioned manner to transfer softened plastic to the individual injector units and attached mold workstations.
Mold workstation 18 depicts one embodiment of the clamping mechanism. In this illustration the injection unit 100 provides for a pressurized flow of plastic into mold workstation 18 . Mold sections are forced together by piston 192 which operates in conjunction with hinge members 194 to securely lock the plate mold in a closed position upon placement of the hinge members in a parallel plane forming a direct wedge between a rear plate 204 and the mold support plate 186 . The locking arrangement permits the mold 180 and 182 to receive the pressurized plastic.
Mold workstation 22 depicts the clamp mechanism in an open position. In this illustration the injection unit 100 ′ again provides for a pressurized flow of plastic into the mold workstation 22 . Mold sections are forced open by piston 192 which operates in conjunction with hinge members 194 to open the plate mold upon placement of the hinge members in a non-parallel plane to eliminate the wedge between rear plate 204 and the mold support plate 186 . The open arrangement permits access to contents of molds 180 and 182 .
Mold workstation 26 , FIGS. 1 and 5 depict the preferred embodiment of the clamping mechanism in a closed position for receipt of pressurized plastic. In this illustration the injection unit provides for a pressurized flow of plastic into mold workstation 26 . Mold sections are forced together by illustrated piston 322 which operates in conjunction with wedge shaped securement device 324 to securely lock the mold in a closed position by forming a direct wedge between rear plate 330 and the end of the tiebars. Cylinders 340 and 342 are used to position the mold in a closed position before the wedge shaped securement devices lock the mold.
Mold workstation 27 depicts the preferred embodiment of the clamping mechanism in an open position for removal of a completed component. Mold sections are unlocked by the retraction of illustrated piston 322 ′ which operates in conjunction with wedge shaped securement device 324 ′ to securely lock the mold in a closed position. Cylinders 340 ′ and 342 ′ are then used to place the mold in an open position.
FIG. 2 depicts the injection unit 100 having a lower housing 102 forming chamber 104 . Softened plastic from the extrusion machine is fed through the manifold and into the coupling lines 30 for placement into chamber 104 . Check valve 108 prohibits the back flow of plastic into the manifold.
The lower housing 102 is secured to upper housing 112 by mounting bolts 114 . The upper housing 112 contains a plastic driving piston 116 having a distal end 118 for engaging the plastic within chamber 104 that enters in the direction of arrow 107 . The piston 116 has sealing rings 122 to prevent bypass around the piston.
The piston is part of a step up pressure multiplier. In this manner, piston 116 is preferably constructed of 4130 steel hardened to RC 45-55 with an outer diameter surface ground and polished for minimal fluid bypass. The piston 116 has a diameter of approximately 6 inches and provides an area of 28.27 square inches. The upper end 120 of piston 116 is coupled to a 10 inch diameter cylinder 124 , having an area of 78.54 square inches, and is secured to the piston 116 by mounting bolt 121 . The cylinder 124 is sealed to the piston by use of seal 123 .
Hydraulic fluid for operation of the piston is controlled by a solenoid valve 128 having a pressurized inlet 129 for delivery of fluid at discharge pressure through coupling pipe 130 and an outlet 127 for return of fluid to a reservoir 400 . The solenoid has an actuator 131 to control the speed of fluid and pressure delivered through the solenoid. The hydraulic fluid is inserted in the space 126 above cylinder 124 at a pressure of 2000 psi providing a force of 157,080 lbs, thus, the resulting force on the plastic within the chamber is 5,556 psi. The cylinder 124 employs steel rings 132 and 134 with a Teflon ring 136 positioned beneath the steel rings for sealing of the fluid. End cap 138 is bolted 140 to the upper housing allowing for ease of maintenance to the cylinder 124 and piston 116 . End cap 138 is sealed by o-ring seal 139 placed around the outer diameter of the end cap 138 with the bolts 140 holding the end cap securely in position.
In operation, plastic is inserted through inlet 106 which forces the piston 116 upward allowing the chamber 104 to be filled with a predetermined amount of plastic. The band heaters 146 and heated injection unit 110 maintain the plastic in a softened state. Upon demand, the plastic is delivered through outlet 142 into the workstation mold. The coupling pipe includes band heaters 146 for maintaining of the plastic in a softened state for placement through nozzle opening 148 . Thermocouple 150 and 152 verify plastic temperature and control shut off valve 154 to prevent plastic flow if necessary.
FIG. 2A sets forth a cross sectional side view of the check valve 108 . Seat 111 includes spacial openings to allow the flow of plastic during the filling process, at low pressure. However, the ball 109 engages seal 113 during a back flow position to prevent the return flow of plastic. The mass of high pressure plastic is capable of displacing the ball 109 to form the seal to prevent the backflow condition. If a backflow condition exists, such as when the chamber is pressurized, the ball 109 is pushed against seal 113 to prevent plastic from escaping the chamber. Band heaters 115 are located around the check valve to maintain the plastic in a fluid state. It is noted that the check valve depicted is used through the module for control of plastic flow where needed.
FIG. 3 depicts the mold workstation 18 coupled to the manifold injection unit 100 by coupling pipe 106 A. The injection unit 100 provides the high pressure flow of plastic into the mold workstation 18 ; having a split mold defined by first section 180 securable to fixed plate 184 and a second section 182 movably securable to plate 186 . The plates and molds are maintained in alignment by tiebars as depicted by numerals 188 and 190 . It is noted that the tiebars form the super structure for support of the plates and molds.
The means for moving plate 186 , and second section of spit mold, also referred to as mold 182 , into a position for accepting plastic injection is performed by use of piston actuator 192 which operates in conjunction with hinge members to lock the plate 186 in a fixed position. A first hinge 194 consists of hinge arm 198 having a proximal end 196 secured to the first plate 186 and hinge arm 202 having a proximal end 200 coupled to end plate 204 with each said hinge arms having a proximal end coupled together and secured to the piston actuator 192 at pinion point 206 . A second hinge member 207 has a distal end 208 of a first hinge arm 210 secured to the first plate 186 and a distal end 212 of a second hinge arm 214 secured to end plate 204 with said first 210 and second 214 hinge arms having a proximal end coupled together and secured to the piston actuator 192 by tying bracket 218 . The spaced apart positioning of the proximal ends places the hinge members in a parallel position to maintain the mold in a closed position. In this position, the mold is ready to accept the injection of plastic from the injection unit 100 .
FIG. 4 depicts the mold workstation 18 in an opened position. the mold workstation is again manipulated by a first section 180 secured to fixed plate 184 and a second section 182 securable to plate 186 . In this manner the first hinge member is dislocated wherein the first hinge arm 198 and second hinge arm 202 are moved which causes an over center hinge coupling thereby moving the plate 186 toward end plate 204 . The second hinge member employing hinge arm 210 and 214 to provide uniform movement of plate 186 .
The second portion 182 of the split mold has a plurality of apertures allowing for the protrusion of ejectors 234 through surface 236 for expelling of the molded piece of plastic when the molds are separated. The ejectors can be secured to bracket 230 causing protrusion of the ejectors upon retraction of plate 186 , preferably the ejectors are coupled to a hydraulic piston 232 to allow for movement of the ejectors as needed.
Referring to FIG. 4, the mold workstation 18 is shown coupled to the manifold injection unit 100 by coupling pipe 106 A. The injection unit 100 provides the high pressure flow of plastic into the mold workstation 18 ; having a split mold defined by first section 180 securable to fixed plate 184 and a second section 182 movably securable to plate 186 . The plates and molds are maintained in alignment by tiebars as depicted by numerals 188 and 190 . It is noted that tiebars form the super structure for support of the plates and molds.
The means for moving plate 186 , and mold 182 , into a position for accepting plastic injection is performed by use of piston actuator 192 which operates in conjunction with hinge members to lock the plate 186 in a fixed position. A first hinge 194 consists of hinge arm 198 having a proximal end 196 secured to the first plate 186 and hinge arm 202 having a proximal end 200 coupled to end plate 204 with each said hinge arms having a proximal end coupled together and secured to the piston actuator 192 at pinion point 206 . A second hinge member 207 has a distal end 208 of a first hinge arm 210 secured to the first plate 186 and a distal end 212 of a second hinge arm 214 secured to end plate 204 with said first 210 and second 214 hinge arms having a proximal end coupled together and secured to the piston actuator 192 by tying bracket 218 . The spaced apart positioning of the proximal ends place the hinge members in a parallel position to maintain the mold in a closed position. In this position, the mold is ready to accept the injection of plastic from the injection unit 100 .
Now referring in general to FIGS. 5 and 6, set forth is the preferred embodiment of the mold workstation depicted by numeral 26 . The mold workstation 26 is coupled to the injector unit 100 ′ by coupling pipe 106 A′. As with the previously described alternative embodiment of the mold workstation, the injection unit 100 ′ is coupled to the heated manifold by pipe 30 ′ with backflow prevented by use of check valve 108 ′.
In the preferred embodiment, the mold workstation 26 consists of a fixed support plate 300 having tiebars 302 , 304 , 306 , and 308 . The tiebars are secured to support plate 300 by use of a coupling nut 310 located on a first side surface of the support plate 300 and a second coupling nut 312 located on the opposite side surface of the support plate 300 . Each shaft, as depicted by shaft 302 , includes a threaded end portion 314 having a key slot 316 which allows for directional receipt of slotted wear washer 318 held in position by adjustable securement nut 320 . Unique to this embodiment is the use of four piston actuators, as illustrated in FIG. 6 . Each actuator, as depicted by numeral 322 , is coupled to a slidable wedge shaped securement device 324 for use in spacial spreading the distance between wear washer 318 and wear plate 326 .
The slidable wedge shaped securement device includes an angle shape and is operatively associated with wear plate 326 to maintain an engagement alignment when not used for said spacial spreading. Preferably the wedge shaped securement device 324 is approximately twelve inches in length which allows sufficient room for removal of finished products and allows for servicing of the molds. In operation, the wedge shaped securement device 324 causes the first portion of split mold 332 to lock against the second portion of split mold 334 thereby allowing for receipt of the highly pressurized plastic from injection unit 100 ′. The mold plate 330 is securely locked in position upon the positioning of the wedge members 324 between the wear plate and wear washer. Upon retraction of the wedge member, the mold plate 330 may be opened by pistons 340 and 342 A used to provide a spatial distance between support plate 300 and movable mold plate 330 allowing access to the mold chamber. The wear plate 326 is replaceable and formed at a reciprocal angle to the angled wedge shaped securement device 324 . Each angle increasing the spacial separation to create a positive seal between the mold sections. Securement nut 320 is used to accommodate for wear of the plate 326 or washer 318 as well as allow for various size molds to be placed within the mold workstation. The threaded nut may also be used to accommodate various size molds.
FIG. 6 depicts an end view of the preferred mold workstation embodiment having the piston actuators shown engaging the tiebar shafts. As previously described, movable plate 330 is first positioned by use of cylinders 340 and 342 . The wedge-shaped securement devices are retracted from engagement with the alignment shafts to allow an opening of the mold of approximately twelve inches. It will be obvious to one skilled in the art that the size of the wedge shaped securement device may be altered as well as that of the spatial wear washers without defeating the intent of this invention. Piston actuator 322 is shown engaging shaft 302 . Similarly, piston actuator 342 engages shaft 306 , piston 344 actuator is used for engaging shaft 308 , and piston actuator 346 is used for engaging shaft 304 . The wear plate 326 includes a lip for maintaining the wedge shaped securement device 324 in alignment while in a retracted position.
Referring now to FIG. 7, shown in an enlarged side view of the movable mold plate 330 having piston actuator 322 inserting wedge shaped securement device 324 between the wear plate 326 and wear washer 318 juxtapositioned to the securement nut 320 . The wear washer includes a tab, not shown, operatively associated with key way 316 for use in preventing rotation of the wear washer during engagement. A portion of the shaft 314 is threaded allowing for use of various size molds as well as to accommodate excessive wear of the wear plate and wear washer.
FIG. 8 is a flow pictorial diagram of the hydraulic system for the instant invention which allows operation of multiple mold work stations from a single pump. In this manner, a hydraulic reservoir is fluidly coupled to a circulating pump 402 which pressurizes hydraulic oil maintained at a high operating pressure by use of a hydraulic accumulator 404 . The hydraulic accumulator 404 is capable of storing the pressurized oil and allowing for an immediate disbursement as necessary. The hydraulic fluid is then available to operate the hydraulic system in the module namely the extruder machine, the injector units 100 including the operating solenoid valves 128 , the piston actuators 131 for engagement of the wear plate, as depicted by number 300 , the piston cylinders as depicted by numeral 340 , and the ejectors as depicted by numeral 232 . Hydraulic volume is returned at low pressure to return pipe 406 back to reservoir 400 .
Referring now to FIG. 9, a pictorial view of a particular embodiment of a continuous extrusion, multiple mold station, injection molding system is shown. A central extrusion machine 10 provides a source of molten plastic. The extrusion rate (lbs/hr.) and speed of the extruder screw (rpm's) necessary to maintain the molten plastic at a specified pressure is determined by pressure transducer 910 , through which the molten plastic passes as it travels from the extrusion machine 10 to the heated manifold 14 wherein it fills the accumulator/injection units 100 , for pressure multiplication and ultimate filling of the high pressure injection molding stations, herein illustrated as double clamp molding stations 912 . These molding stations utilize one common stationary central plate 914 for two independent and distinct movable plates 916 to define two separate molding stations which comprise the double clamp molding station 912 . In operation, each of the movable plates 916 , can be retracted for extraction of finished parts from the molds, then the movable plates can be independently slid back into locking engagement and the wedge shaped securement devices 324 are forced into locking engagement via actuators 322 , so as to positively position the mold halves for the next injection of high pressure molten plastic.
It is to be understood that while we have illustrated and described certain forms of our invention, it is not to be limited to the specific forms or arrangement of parts herein described and shown. It will be apparent to those skilled in the art that various changes may be made without departing from the scope of the invention and the invention is not to be considered limited to what is shown in the drawings and described in the specification. | Disclosed is a high pressure injection molding system employing one or more plastic injection molding workstations including split molds, a single plastic extruder coupled to a heated manifold capable of delivering fluid plastic to multiple workstations, and wherein final lockup of the split mold halves results in application of compressive forces effective to maintain the split mold halves in nominal position during high pressure injection molding conditions. Operational movement is performed by use of a single remote pumping station utilizing pressure compensated pumps, accumulators and manifolds. The independent mold workstations allow independent operation while providing efficency of operation for the hydraulic system and extruder system. | 1 |
This Application is a continuation of application Ser. No. 08/434,820, filed May 4, 1995, now abandoned, which is a division of application Ser. No. 08/077,599, filed Jun. 15, 1993, now U.S. Pat. No. 6,348,181.
FIELD OF THE INVENTION
The present invention relates to a new process and apparatus for producing furnace carbon blacks.
BACKGROUND
Carbon blacks are widely utilized as pigments in ink compositions, paints and the like; as fillers and reinforcing pigments in the compounding and preparation of rubber compositions and plastic compositions, and for a variety of other applications. Carbon blacks are generally characterized on the basis of their properties including, but not limited to, their surface areas, surface chemistry, aggregate sizes and particle sizes. The properties of carbon blacks are analytically determined by tests known to the art.
Carbon blacks are generally produced in a furnace-type reactor by reacting a hydrocarbon feedstock with hot combustion gases to produce combustion products containing particulate carbon black. In the carbon black literature, this reaction between the combustion gases and the hydrocarbon feedstock is generally referred to as pyrolysis.
A variety of methods for producing carbon blacks are generally known. In one type of a carbon black furnace reactor, such as shown in U.S. Pat. No. 3,401,020 to Kester et al., or U.S. Pat. No. 2,785,964 to Pollock, hereinafter “Kester” and “Pollock” respectively, a fuel, preferably hydrocarbonaceous, and an oxidant, preferably air, are injected into a first zone and react to form hot combustion gases. A hydrocarbon feedstock in either gaseous, vapor or liquid form is also injected into the first zone whereupon reaction of the hydrocarbon feedstock commences. The resulting combustion gas mixture, in which the reaction is occurring, then passes into a reaction zone where completion of the carbon black forming reaction occurs.
In another type of carbon black furnace reactor a liquid or gaseous fuel is reacted with-an oxidant, preferably air, in the first zone to form hot combustion gases. These hot combustion gases pass from the first zone, downstream through the reactor, into a reaction zone and beyond. To produce carbon blacks, a hydrocarbonaceous feedstock is injected at one or more points into the path of the hot combustion gas stream. The hydrocarbonaceous feedstock may be liquid, gas or vapor, and may be the same or different than the fuel utilized to form the combustion gas stream. Generally the hydrocarbonaceous feedstock is a hydrocarbon oil or natural gas. The first (or combustion) zone and the reaction zone may be divided by a choke or zone of restricted diameter which is smaller in cross section than the combustion zone or the reaction zone. The feedstock may be injected into the path of the hot combustion gases upstream of, downstream of, and/or in the restricted diameter zone. The hydrocarbon feedstock may be introduced in atomized and/or non-pre atomized form, from within the combustion gas stream and/or from the exterior of the combustion gas stream. Carbon black furnace reactors of this type are generally described in U.S. Reissue Pat. No. 28,974, to Morgan et al., and U.S. Pat. No. 3,922,335, to Jordan et al., the disclosure of each being incorporated herein by reference.
In generally known reactors and processes, the hot combustion gases are at a temperature sufficient to effect the reaction of the hydrocarbonaceous feedstock injected into the combustion gas stream. In one type of reactor, such as disclosed in Kester, feedstock is injected, at one or more points, into the same zone where combustion gases are being formed. In other type reactors or processes, the injection of the feedstock occurs, at one or more points, after the combustion gas stream has been formed. The mixture of feedstock and combustion gases in which the reaction is occurring is hereinafter referred to, throughout the application, as “the reaction stream”. The residence time of the reaction stream in the reaction zone of the reactor is sufficient to allow the formation of desired carbon blacks. In either type of reactor, since the hot combustion gas stream is flowing downstream through the reactor, the reaction occurs as the mixture of feedstock and combustion gases passes through the reaction zone. After carbon blacks having the desired properties are formed, the temperature of the reaction stream is lowered to a temperature such that the reaction is stopped.
U.S. Pat. No. 4,327,069, to Cheng (“Cheng '069”), and its divisional, U.S. Pat. No. 4,383,973, to Cheng (“Cheng '973”), disclose a furnace and a process for producing carbon black having a low tint residual utilizing two carbon black reactors. “Each of the carbon black reactors has a precombustion section, a reaction section, hydrocarbon inlet means, and hot combustion gas inlet means”. Cheng '973, Col. 4, 11. 16-19. One of the reactors is a high-structure carbon black reactor, and the other reactor is a low-structure carbon black reactor. Cheng '973, Abstract. “A second flow of hot combustion gases formed by the combustion of a second fuel stream and a second oxygen containing stream is established in the second carbon black forming zone. A second stream of hydrocarbon feedstock is introduced into the second carbon black forming zone of the furnace into admixture with the second flow of hot combustion gases established therein as well as with the first carbon black forming mixture coming from the first carbon black forming zone of the furnace.” Cheng '973, Col. 2, 11. 19.
SUMMARY OF THE INVENTION
I have discovered that it is possible to reduce the amount of fuel utilized to produce carbon black by reacting the reaction stream of a prior carbon black forming process with an oxidant to generate a stream of combustion products that will react with carbon black yielding feedstock to produce carbon black. The generation of this stream of combustion products may be accomplished by introducing any suitable oxidant, which may be any oxygen containing material such as air, oxygen, mixtures of air and oxygen, or other like materials into the reaction stream. The resulting stream of combustion products is reacted with additional carbon black yielding feedstock to produce carbon black. As a result, the amount of fuel utilized for producing carbon black is reduced.
Accordingly, the process of the present invention is a process for producing carbon black comprising:
reacting a reaction stream formed by a prior carbon black forming process with an oxidant and a carbon black yielding feedstock to produce carbon black; and
cooling, separating and recovering the carbon black. Preferably, the process further comprises:
forming the reaction stream by a process comprising reacting a fuel with an oxidant and a carbon black yielding feedstock; and
reacting the reaction stream with oxidant and carbon black yielding feedstock under conditions that reduce the amount of fuel utilized to produce the total amount of carbon black produced by the process. The fuel reduction is observed in the amount of fuel utilized per pound of carbon black produced by the process when compared to the amount of fuel utilized per pound of carbon black to form the reaction stream. More particularly, the amount of fuel utilized, per pound of carbon black, to produce the total amount of carbon black produced by the process, is less than the amount of fuel, per pound of carbon black, utilized to produce a carbon black, of not less than substantially the same CTAB surface area, by the process which formed the reaction stream. If one operates a typical carbon black producing process to produce a carbon black of a given CTAB surface area, and, prior to cooling, separating and recovering the carbon black, reacts the reaction stream with an oxidant and carbon black yielding feedstock, according to the process of the present invention, it is possible and practicable to produce more total carbon black of not less than substantially the same CTAB surface area at a lower specific fuel consumption (BTU/pound of carbon black) than the typical carbon black forming process preceding the reaction between the reaction stream and the oxidant and carbon black yielding feedstock. Preferably, the reduction in the amount of fuel is at least 2%.
As will be understood by those of ordinary skill in the art, the process steps of reacting a reaction stream with an oxidant and a carbon black yielding feedstock to produce carbon black may be repeated, as often as practicable, prior to cooling, separating and recovering the carbon black.
From the Examples described herein, and cited in Tables 4 and 5 below, it is evident to one of ordinary skill in the carbon black art that significant fuel savings have been achieved by the practice of my invention. In the Examples, the reaction stream was generated in a carbon black furnace reactor similar to those described in U.S. Reissue Pat. No. 28,974, to Morgan et al., and U.S. Pat. No. 3,922,335, to Jordan et al. However, the process of the present invention may be performed using any means of forming the reaction stream. For example, the process of the present invention may be performed, and useful fuel savings could be achieved, utilizing a reaction stream formed in the following generally known types of reactors: a typical carbon black furnace reactor of the type described in U.S. Pat. No. 2,641,534; and a set of thermal carbon black reactors appropriately ganged and valved so as to provide a substantially continuous reaction stream.
“Oxidant”, as used herein, refers to any oxidizing agent suitable for maintaining a fire, such as, for example, air, oxygen and mixtures thereof, with air being the preferred oxidant. The process of the present invention may even gainfully employ air with reduced oxygen content. It is within the context of the present invention to vary the composition of the oxidant, through the introduction of additives.
Oxidant may be introduced into the reaction stream in any manner known to the art. For example, and preferably, the oxidant may be introduced by attaching a conduit to a port through the walls of the reactor. However, oxidant should be introduced in a manner, or the reactor configured in a manner, such that the oxidant is rapidly mixed into the reaction stream. The mixing of the oxidant into the reaction stream may be accomplished by methods which include, but are not limited to, the following methods: introducing the oxidant under sufficient pressure to penetrate the reaction stream; or configuring the reactor to include a recirculation zone to allow the mixing of the oxidant into the reaction stream.
Carbon black-yielding hydrocarbon feedstocks, which are readily volatilizable under the conditions in the reactor, include unsaturated hydrocarbons such as acetylene; olefins such as ethylene, propylene, butylene; aromatics such as benzene, toluene and xylene; certain saturated hydrocarbons; and volatilized hydrocarbons such as kerosenes, naphthalenes, terpenes, ethylene tars, aromatic cycle stocks and the like.
Carbon black yielding feedstock may be introduced into the reaction stream simultaneously with or subsequent to the introduction of the oxidant. The feedstock may be introduced in atomized and/or non-pre atomized form from within the reaction stream, and/or from the exterior of the reaction stream. The time between the introduction of the oxidant, and the introduction of the carbon black yielding feedstock, should allow sufficient time for the mixing of the oxidant and the reaction stream, such that the reaction between the oxidant and the reaction stream generates a stream of combustion products to react the carbon black yielding feedstock.
Preferably, in the process of the present invention, the time between the introduction of the oxidant and the introduction of the carbon black yielding feedstock is less than 30 milliseconds, more preferably less than 10 milliseconds, most preferably less than 5 milliseconds.
Introduction of the oxidant into the reaction stream generates sufficient heat to react the carbon black yielding feedstock. The reaction stream may then be passed into another reaction zone to permit the introduction of additional oxidant and additional carbon black yielding feedstock according to the process of the present invention.
After carbon blacks having the desired properties are formed the temperature of the reaction stream may be lowered, in any manner known to the art, such as by injecting a quenching fluid, through a quench, into the reaction stream. One way of determining when the reaction should be stopped is by sampling the reaction stream and measuring its toluene discoloration level. Toluene discloration is measured by ASTM D1618-83 “Carbon Black Extractables—Toluene Discoloration”. The quench is generally located at the point where the toluene discoloration level of the reaction stream reaches an acceptable level for the desired carbon black product being produced. After the reaction stream has been cooled, the reaction stream may be passed through a bag filter system to separate and collect the carbon black.
An apparatus for carrying out the process of the present invention comprises:
means for reacting a reaction stream formed by a prior carbon black forming process with an oxidant and a carbon black yielding feedstock to produce carbon black; and
means for cooling, separating and recovering the carbon black.
Preferably, the apparatus comprises a plurality of reactor zones in which a reaction stream is formed in a first reaction zone and flows into at least one subsequent reaction zone wherein oxidant and carbon black yielding feedstock are introduced to form carbon black. After the formation of carbon black, the reaction stream is cooled and the carbon black separated and recovered. It is therefore within the contemplation of this invention that the reaction stream may be allowed to flow downstream into additional reaction zones for the introduction of further oxidant and carbon black yielding feedstock.
Other details and advantages of the process and apparatus of the present invention will become apparent from the following more detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cross-sectional diagram of a carbon black reactor of the present invention that may be utilized to perform the process of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
As set forth above, the process and apparatus of the present invention result from my discovery that it is possible to reduce the amount of fuel utilized to produce carbon black by reacting the reaction stream of a prior carbon black forming process with an oxidant to generate a stream of combustion products that will react with carbon black-yielding feedstock to produce carbon black. By mixing an oxidant into the reaction stream, it is practicable to generate a stream of combustion products to react additional carbon black yielding feedstock introduced simultaneously with or subsequent to the introduction of the oxidant.
A carbon black reactor which may be utilized to perform the process of the present invention is depicted in FIG. 1 . Although one type of carbon black reactor is depicted in FIG. 1, it is to be understood that the present invention can be used in any carbon black furnace reactor in which carbon black is produced by reaction of hydrocarbons.
It will also be recognized that the carbon black reactor depicted in FIG. 1 constitutes an apparatus of the present invention. However, the apparatus of the present invention is not limited to the configuration depicted in FIG. 1 .
Referring to FIG. 1, the process of the present invention may be practiced in a carbon black furnace reactor 2 , having: a combustion zone 10 , which has a zone of converging diameter 11 ; a first feedstock injection zone 12 , and a first reaction zone 18 . In the embodiment depicted in FIG. 1, first reaction zone 18 includes a zone of a smaller inner diameter, 19 connected to a zone of converging diameter 20 which communicates with a second feedstock injection zone 22 , having a smaller diameter than first reaction zone 18 . The second feedstock injection zone 22 , is attached to second reaction zone 32 . In the embodiment depicted in FIG. 1, second reaction zone 32 includes a zone of diverging diameter 30 .
For purposes of the Examples described below, the diameter of the combustion zone, 10 , up to the point where the zone of converging diameter, 11 , begins is shown as D- 1 ; the diameter of the converging zone, 11 , at the narrowest point, is shown as D- 2 ; the diameter of zone 12 , as D- 3 , the diameter of zone, 18 , as D- 4 , the diameter of zone 19 , as D- 5 , the diameter of the converging zone 20 , at the narrowest point, as D- 6 , the diameter of zone 22 as D- 7 and the diameter of zone 30 , at the narrowest point as D- 7 and the diameter of zone 32 as D- 8 . Similarly, for purposes of the Examples described below, the length of the combustion zone 10 , up to the point where the zone of converging diameter, 11 , begins is shown as L- 1 ; the length of the zone of converging diameter, 11 , is shown as L- 2 ; the length of the first feedstock injection zone, 12 , is shown as L- 3 ; the length of first reaction zone, 18 , up to the point of the zone of smaller diameter, 19 is shown as L- 4 ; the length of zone 19 is shown as L- 5 ; the length of zone 20 of converging diameter is shown as L- 6 ; the length of second feedstock injection zone 22 is shown as L- 7 ; and the length of the zone of diverging diameter 30 , as L- 8 . L- 9 is the length of the reactor section from the midplane of the point of oxidant introduction 50 to the beginning of the zone of converging diameter 20 .
In the practice of the process of the present invention, hot combustion gases are generated in zone 10 by contacting liquid or gaseous fuel with a suitable oxidant stream such as air, oxygen, mixtures of air and oxygen or the like. Among the fuels suitable for use in contacting the oxidant stream in combustion zone 10 to generate the hot combustion gases are included any of the readily combustible gas, vapor or liquid streams such as natural gas, hydrogen, carbon monoxide, methane, acetylene, alcohols, or kerosene. It is generally preferred, however, to utilize fuels having a high content of carbon-containing components and in particular, hydrocarbons. Operations with fuel equivalence ratios between 10 and 125% are generally preferred when air is used as the oxidant in the combustion reaction in the first zone. As understood by those of ordinary skill in the art, to facilitate the generation of hot combustion gases, the oxidant stream may be preheated.
The hot combustion gas stream flows downstream from zones 10 and 11 into zone 12 and then 18 . Carbon black-yielding feedstock, 40 is introduced at a first point 42 , located in zone 12 . Suitable for use as carbon black-yielding hydrocarbon feedstocks, which are readily volatilizable under the conditions of the reaction, are unsaturated hydrocarbons such as acetylene; olefins such as ethylene, propylene, butylene; aromatics such as benzene, toluene and xylene; certain saturated hydrocarbons; and volatilized hydrocarbons such as kerosenes, naphthalenes, terpenes, ethylene tars, aromatic cycle stocks and the like. In the examples described herein, carbon black-yielding feedstock, 40 , was injected substantially transversely from the periphery of the stream of hot combustion gases in the form of a plurality of small jets which penetrated into the interior regions of the hot combustion gas stream to insure a high rate of mixing and shearing of the carbon black-yielding feedstock by the hot combustion gases, so as to decompose and convert the feedstock to produce carbon black. The distance from the end of the zone of converging diameter 11 , to the first feedstock injection point 42 , is shown as F- 1 .
The mixture of carbon black-yielding feedstock and hot combustion gases flows downstream from zone 12 into first reaction zone 18 . Reaction of the carbon black-yielding feedstock is initiated at the point of feedstock injection. Thus the reaction stream flowing through zone 18 is the reaction stream referred to in the description of the process and apparatus of the present invention.
According to the process of the present invention, an oxidant is introduced into the reaction stream. The point of oxidant injection, in the embodiment depicted in FIG. 1, is shown as 50 . The distance from the beginning of zone 18 , to the point of oxidant injection 50 , is shown as X- 1 .
The oxidant may be introduced into the reaction stream in any manner known to the art. For example, the oxidant may be introduced by attaching a conduit to a port, or ports, through the walls of the reactor. The ports may be disposed in an annular ring around the circumference of zone 19 . It is preferred that the oxidant be introduced in a manner which ensures rapid mixing of the oxidant and the reaction stream in order to generate a stream of combustion products to react the carbon black-yielding feedstock.
In the Examples described below, oxidant was introduced into the reaction stream through a plurality of radial ports peripherally disposed around the reactor.
Additional carbon black-yielding feedstock 60 , is introduced into the reaction stream either substantially simultaneously with the oxidant, or subsequent to the introduction of the oxidant. In the Examples described below the feedstock was introduced subsequent to the introduction of the oxidant. The additional carbon black-yielding feedstock may be the same as or different from the carbon black-yielding feedstock, 40 introduced at the first feedstock injection point 42 .
The point of the additional feedstock introduction is shown in FIG. 1 as 62 . The distance between the point of oxidant introduction, 50 , and the point of additional feedstock introduction 62 , is shown as F- 2 . In the examples described herein, carbon black-yielding feedstock, 60 , was injected substantially transversely from the periphery of the stream of hot combustion gases in the form of a plurality of small jets which penetrated into the interior regions of the hot combustion gas stream to insure a high rate of mixing and shearing of the carbon black-yielding feedstock by the hot combustion gases so as to decompose and convert the feedstock and produce additional carbon black.
The time between the introduction of the oxidant, and the introduction of the carbon black yielding feedstock, should allow sufficient time for the mixing of the oxidant and the reaction stream. Preferably, in the process of the present invention, the time is less than 30 milliseconds, more preferably less than 10 milliseconds, most preferably less than 5 milliseconds. Thus, preferably in the process of the present invention the distance F- 2 is selected such that the time is less than 30 milliseconds. As will be understood by those of ordinary skill in the art, the relationship between the time, and the distance F- 2 will depend on the configuration and dimensions of the reactor, in conjunction with the throughput level being utilized to practice the process of the present invention.
The reaction stream containing the additional carbon black-yielding feedstock flows into and through zones 30 and 32 . Instead of quenching the reaction stream in zone 32 , additional oxidant and feedstock may be introduced into this reaction stream to generate a stream of combustion products to react additional carbon black-yielding feedstock in further reactor zones to produce additional carbon black. These steps may be repeated as often as practicable.
In the embodiment depicted in FIG. 1, quench 70 , located at point 72 , injecting quenching fluid 80 , is utilized to stop the reaction of the carbon black-yielding feedstock. Q is the distance from the beginning of stage 32 , to point 72 , and will vary according to the position of the quench.
After the reaction stream is quenched, the cooled gases containing the carbon blacks of the present invention pass downstream into any conventional cooling and separating means whereby the carbon blacks of the present invention are recovered. The separation of the carbon black from the gas stream is readily accomplished by conventional means such as a precipitator, cyclone separator and bag filter. This separation may be followed by pelletizing using, for example, a wet pelletizer.
The effectiveness and advantages of the present invention will be further illustrated by the following examples in which the cetyl-trimethyl ammonium bromide absorption value (CTAB) was determined according to ASTM Test Procedure D3765-85.
EXAMPLES 1-6
The process of the present invention was utilized to produce carbon black in five exemplary reactor runs, Example Runs 1-5. In carrying out Example Runs 1-5, no additional fuel was introduced into the reaction stream in the second zone of the reactor. For comparison purposes, a control run was conducted wherein carbon black was produced without introduction of oxidant and additional feedstock into the reaction stream, Example Run 6.
The reactor utilized in each example run and the control run was similar to the reactor generally described herein, and as depicted in FIG. 1, utilizing the reactor conditions and geometry set forth in Table 2. The fuel utilized in the combustion reaction in each of the examples was natural gas. The feedstock utilized in each of the Example Runs had the properties indicated in Table 1 below:
TABLE 1
Feedstock Properties
Example
Runs 1-4 & 6
Example Run 5
Hydrogen/Carbon Ratio
0.95
0.96
Hydrogen (wt. %)
7.27
7.44
Carbon (wt. %)
91.6
92.2
Sulfur (wt. %)
0.9
0.6
A.P.I. Gravity 15.6/15.6
−1.3
−1.3
C(60 F.) [ASTM D-287]
Specific Gravity 15.5/15.6
1.087
1.099
C(60 F.) [ASTM D-287]
Viscosity, SUS (54.4° C.)
163.8
106.0
[ASTM D-88]
Viscosity, SUS (98.9° C.)
49.8
41.3
[ASTM D-88]
BMCI (Visc-Grav)
130
131
Pounds carbon/gallon of feedstock
8.30
8.35
The oxidant introduced into the reaction stream in Example Runs 1-5 was air. The oxidant was injected into the reaction stream through a plurality of peripherally disposed radial ports. In Example Runs 1-4 there were employed three 1 inch diameter ports, six ½ inch diameter ports, and six ¼ inch diameter ports, providing a combined air introduction area of approximately 3.8 square inches. In Example Run 5 there were employed three 1 inch diameter ports, three ¾ inch diameter ports, twelve ½ inch diameter ports, and six ¼ inch diameter ports, providing a combined air introduction area of approximately 6 square inches.
The reactor conditions and geometry are set forth in Table 2 below. In Example Run 5, ten pounds per hour of a water solution containing a total of 25 grams of K 2 CO 3 was added to the second feedstock stream.
TABLE 2
Example Runs
Control
Ex. 1
Ex. 2
Ex. 3
Ex. 4
Ex. 5
Ex. 6
D-1, in.
8.75
8.75
8.75
8.75
8.75
8.75
D-2, in.
3.8
3.8
3.8
3.8
3.8
3.8
D-3, in.
3.8
3.8
3.8
3.8
3.8
3.8
D-4, in.
9
9
9
9
9
9
D-5, in.
8.3
8.3
8.3
8.3
8.3
8.3
D-6, in.
5.3
5.3
5.3
5.3
5.3
5.3
D-7, in.
5.3
5.3
5.3
5.3
5.3
5.3
D-8, in.
9
9
9
9
9
9
L-1, in.
24
24
24
24
24
24
L-2, in.
13
13
13
13
13
13
L-3, in.
8
8
8
8
8
8
L-4, in.
70
70
70
70
67
*
L-5, in.
12
12
12
12
12
NA
L-6, in.
2.88
2.88
2.88
2.88
2.88
NA
L-7, in.
1.5
1.5
1.5
1.5
1.5
NA
L-8, in.
2
2
2
2
2
NA
L-9, in.
2.25
2.25
2.25
2.25
12.75
NA
F-1, in.
4
4
4
4
4
4
F-2, in.
6
6
6
6
16.5
NA
X-1, in.
80.5
80.5
80.5
80.5
67
NA
Q, in.
120
72
72
72
216
56
1st Zone
Comb. Air, kscfh
45.0
45.2
45.0
35.0
35.0
100
Comb. Air
896
902
886
876
900
907
Preheat, F.
Nat. Gas, kscfh
3.72
3.71
3.67
2.85
2.89
8.75
Fstk Inj Pt. 42,
4 ×
4 ×
4 ×
4 ×
4 ×
6 ×
Tips # ×
0.026
0.038
0.052
0.052
0.033
0.043
Size, in.)
Fstk Rate 42,
45.1
71.2
97.7
76.0
72.0
169.7
gph
Fstk Press. 42,
228
137
72
43
155
170
psig
Pstk Preheat,
251
248
243
243
310
297
42, F
2nd Zone
Air Entrance
3.8
3.8
3.8
3.8
6
NA
Area sq. in.
Comb. Air, kscfh
55.0
54.8
55.0
64.9
65.0
NA
Comb. Air
966
994
1001
1093
1000
NA
Preheat, F.
Fstk Inj. Pt. 62,
7 ×
7 ×
7 ×
7 ×
7 ×
NA
Tips, # ×
0.043
0.029
0.029
0.029
0.037
Size, in.)
Fstk Rate 62,
163.8
118.3
111.6
99.6
143.0
NA
gph
Fstk Press. 62,
184
310
283
223
203
NA
psig
Fstk Preheat
237
239
240
233
281
NA
62, F.
Temp. at
1349
1351
1351
1350
1350
1350
Quench, F.
*In control run 6, a single reactor stage, 18, was utilized. The reaction stream was quenched at the end of this reactor stage, thus L-4 = Q.
First Zone refers to the portion of the reactor upstream from the point of oxidant introduction in the Second Zone. Second Zone refers to the portion of the reactor including, and downstream, of the point of oxidant introduction in the Second Zone. Air entrance area refers to total combined surface area of the ports in the annular ring through which oxidant was introduced into the reaction stream in the Second Zone.
Inj. = Injection; Comb. = combustion; Press. = pressure; Fstk = feedstock; 42 = Point 42 on FIG. 1; 62 = Point 62 on FIG. 1; gph = gallons/hour; psi = pounds/square inch.; in. = inches; ft. = feet; sq. in. = square inches; F = degrees Fahrenheit; kscfh = standard cubic feet/hour, in 1000's; NA = not applicable
After quenching the process stream proceeded through typical downstream equipment utilized in carbon black production facilities for further cooling the reaction stream. The carbon blacks produced in each run were separated and collected using conventional means employing bag filters, and were then pelletized in a conventional manner using a wet pelletizer.
As shown in Table 2 the distance, F- 2 , between the centerline of the plane of the oxidant introduction ports ( 50 on FIG. 1) and the centerline of the plane of the second feedstock introduction ports ( 62 on FIG. 1) was 6 inches in Example Runs 1-4. The internal volume of the reactor between these two planes, in Example Runs 1-4, was approximately 247 cubic inches. The estimated time between the oxidant introduction and the feedstock introduction was about 0.6 milliseconds, in Example Runs 1-4, assuming the combustible gases from the reaction stream formed earlier are immediately burned to CO 2 and water. In Example Run 5 the distance, F- 2 , was 16.5 inches and the internal volume of the reactor between the plane of oxidant introduction and the plane of feedstock introduction, in Example Run 5, was approximately 788 cubic inches. The estimated time between the oxidant introduction and the feedstock introduction was about 2 milliseconds, in Example Run 5, assuming the combustible gases from the reaction stream formed earlier are immediately burned to CO 2 and water.
It should be appreciated that while the above description is particular to one type of apparatus, the invention is achieved through the mixing of the oxidant and the reaction stream to generate a stream of combustion products to react carbon black-yielding feedstock to produce carbon black.
The CTAB values of the dried carbon blacks produced in each exemplary run were determined by the aforementioned testing method. The carbon black yield (pounds of carbon black per gallon of feedstock) of each run was determined using gas chromatographic analysis of the flue gas exiting the bag filter, as well as occasional weight checks. The fuel used in each run, expressed as B.T.U. per pound of carbon black produced was also calculated for each example run. The results are set forth in Table 3.
TABLE 3
Ex. 1
Ex. 2
Ex. 3
Ex. 4
Ex. 5
Ex. 6
CTAB (m 2 /g)
89
120
88
108
77
92
Yield
5.31
5.16
5.58
4.73
5.28
5.79
(lbs. c.b./gal.
fstk)
Fuel Usage*
31360
32590
29800
34900
30770
34220
(B.T.U./
lb. c.b.)
lbs. c.b. = pounds of carbon black; gal. fstk = gallon of feedstock
c.b. = carbon black
*The Fuel usage values were determined assuming values of 928 B.T.U./scf for natural gas (lower heating value) and 150,000 B.T.U./gallon for feedstock (lower heating value).
These results indicate that the fuel usage in each of Example Runs 1 and 3, which utilized the process of the present invention was significantly reduced in comparison with the fuel usage of the control run, Example Run 6.
A comparison of the multi-zone process of the present invention, Example Runs 1-5, and a single reaction zone process is set forth in Tables 4 and 5 below.
TABLE 4
Ex. 1
Ex. 2
Ex. 3
Ex. 4
Ex. 5
Ex. 6
Multi
Multi
Multi
Multi
Multi
Single
TOTAL Air,
100
100
100
99.9
100
100
kscfh
TOTAL Gas,
3.72
3.71
3.67
2.85
2.89
8.75
kscth
TOTAL Fstk,
208.9
189.5
209.3
175.6
21S
168.7
gph
Yield
5.31
5.16
5.58
4.73
5.28
5.79
(pounds/gal.
fstk)
Throughput
1109
978
1168
830
1135
977
(lb. c.b./hr.)
CTAB (m 2 /g)
89
120
88
108
77
92
Fuel Usage*
31360
32590
29800
34900
30770
34220
(B.T.U./lb.
c.b.)
lb. c.b. = pound of carbon black; gal. fstk = gallon of feedstock; Throughput = TOTAL Fstk × Yield
*The Fuel Usage values were determined assuming values of 928 B.T.U./scf for natural gas (lower heating value) and 150,00 B.T.U./gallon for feedstock (lower heating value).
It is estimated that to achieve the same yields and throughputs as shown in Example Runs 1-5, in a single stage process producing carbon blacks of the same respective CTAB surface areas, it would have required the amounts of air, gas and feedstock set forth in Table 5. The estimated fuel usage based on the estimated amounts of air, gas and feedstock is also set forth in Table 5. The percent reduction in fuel usage is additionally set forth in Table 5.
TABLE 5
Ex. 1
Ex. 2
Ex. 3
Ex. 4
Ex. 5
Ex. 6
< Hypothetical Single Stage >
Single
Est. TOTAL
110.4
112.6
114.3
117.2
109.2
100
AIR, kscfh
(actual)
Est. TOTAL
7.59
8.01
8.99
8.2
6.53
8.75
GAS, kscfh
(actual)
Est. TOTAL
208.9
189.5
209.3
175.6
215
168.7
Fstk, gph
(actual)
Est. Fuel Usage
34600
36670
34030
40870
33750
34220
(B.T.U./lb.
(actual)
c. b.)
% Reduction in
8.8
11.1
12.4
14.6
8.9
N.A.
Fuel Usage
A comparison of the results provided in Table 4, and the estimates provided in Table 5, shows that Example Runs 1-5, in Table 4, exemplary of the process of the present invention, achieved useful gains, on the order of 8 to 15%, in energy efficiency in comparison with a single reaction zone process making a similar carbon black.
It should be clearly understood that the forms of the present invention herein described are illustrative only and are not intended to limit the scope of the invention. | A process for producing carbon black comprising reacting a reaction stream formed by a prior carbon black forming process with an oxidant and a carbon black yielding feedstock to produce carbon black and cooling, separating and recovering the carbon black. The process advantageously reduces the amount of fuel needed to produce carbon black. Also disclosed is an apparatus for practicing the process. | 2 |
SUMMARY
The invention is about a series of novel symmetric amides of 1,4-bis-substitued alkylenediamino-5,8-dihydroxyanthraquinones with various monocarboxylic acid, which exist in the human organism, as well as other monocarboxylic acids, which can be obtained from substances, which exist in the human organism. These monocarboxylic acids are among others those, which contain a quaternary ammonium group, like for instance 3-hydroxybutyric acid-4-trimethylammoniumchloride (carnitine chloride) and Acetic acid trimethylammonium chloride, an oxidation product of choline, the N-acetyl neuraminic acid, as well as monocarboxylic derivatives of various sugar molecules, for example gluconic acid or 2-amino gluconic acid.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention is about a series of novel symmetric amides of 1,4-bis-substituted alkylenediamino-5,8-dihydroxyanthraquinones with various monocarboxylic acid, which exist in the human organism, as well as other monocarboxylic acids, which can be obtained from substances, which exist in the human organism. These monocarboxylic acids are, among others, those which contain a quaternary ammonium group, like for instance 3-hydroxybutyric acid-4-trimethylammoniumchloride (carnitine chloride) and acetic acid trimethylammonium chloride, an oxidation product of choline, the N-acetyl neuraminic acid, as well as monocarboxylic derivatives of various sugar molecules, for example gluconic acid or 2-amino gluconic acid.
2. Description of the Related Art
About three decades ago, the first anthracycline antibiotics were obtained through biological synthesis by fungus Streptomyces paucetius var. caesius. As described in the classical reference book by A. Goodman Gilman, L. S. Goodman, T. W. Rall, F. Murad, "Goodman Gilman's Pharmaceutical Basis of Therapeutics", 7th edition, McMillan Publishing Company, New York, 1985, pp 1283, anthracycline antibiotics and their derivatives show a very strong antitumor activity. One representative of this group is daunorubicine. It was isolated independently by both DiMarco and Dubost et al. in 1963. A very similar compound is the doxorubicine. It was first isolated in 1969 by Arcamone. Although these two compounds are very similar in structure, daunorubicine is primarily used in acute leukemias while doxorubicine is applied against a wide range of human neoplasms including solid tumors.
However both of these compounds showed also toxic effects to the organism (Goodman Gilman's Pharmaceutical Basis of Therapeutics, 7th edition, 1985), and can cause, depending on the dose applied, an often irreversible cardiomyopathia. Following the invention of the first anthracycline antibiotics, several anthracycline derivatives were prepared and tested in order to find an alternative compound with high antitumor activity, but at the same time with reduced cardiac toxicity. Mitoxantrone, a synthetically obtained compound, is one of these antitumor agents. It is an aminoanthracenedione (1,4-bis[2-(2-hydroxyethylamino)ethylamino]5,8-dihydroxyanthraquinone hydrochloride) and is used very frequently against various neoplastic developments in human organism. The U.S. Pat. No. 4,197,249 from 1980 is about a series of substituted anthraquinone derivatives, including mitoxantrone.
The scientific publications of Zee-Cheng and Cheng (R. K.-Y. Zee-Cheng, C. C. Cheng, "Antineoplastic agents. Structure-reactivity relationship study of bis (substituted aminoalkylamino) anthraquinones, Journal of Medicinal Chemistry, volume 21, year 1978, pages 291-294) and of Murdock et al. (K. C. Murdock, R. G. Child, P. F. Fabio, R. B. Angier, R. E. Wallace, F. E. Durr, R. V. Citarella, "Antitumor agents. 1. 1,4-Bis[(aminoalkyl)amino]-9,10-anthracenediones", Journal of Medicinal Chemistry, Volume 22, year 1979, pages 1024-1030) report about various compounds of this class.
BRIEF DESCRIPTION OF THE INVENTION
It is the objective of the invention, to synthetise new hydroxyanthraquinone derivatives, which show a very strong antineoplastic activity and using which medicines can be produced that are appropriate for chemotherapeutic treatment of cancerous diseases.
The idea of the invention is, to combine derivatives of 1,4-bis-substituted alkylenediamino-5,8-dihydroxyanthraquinone through amide bond with acyl groups of monocarboxylic acid, which contain a quaternary ammonium groups, or with monocarboxylic acids, which are derivatives of various sugar molecules, or with acyl groups of monocarboxylic acids which are N-acetyl neuraminic acid or its derivatives. These acyl groups are derived from monocarboxylic acids, which exist in the human organism, or can be derived from compounds that exist in the human organism. A hydroxyanthraquinone derivative with these groups will then show a strong antineoplastic effect, since by these appropriate substituents, even very small amounts of this compound will be transferred into the cancerous cells as well as into the mitochondria, where the malignant transformation of the deoxyribonucleic acid begins.
DETAILED DESCRIPTION OF THE INVENTION
This invention is about a new series of organic compounds and particularly the symmetric amides of the 1,4-bis substituted amino-5,8-dihydroxyanthraquinones with carboxylic acids, which may be represented by the following formula ##STR2## wherein Z is a divalent moiety consisting of a linear or branched, saturated or unsaturated alkylene group. The ##STR3## is the acyl group of various monocarboxylic acids that exist in the human organism, or a monocarboxylic acid, which can be obtained by a reaction from compounds that exist in the human organism, as well as pharmacologically acceptable acid addition salts of them. These monocarboxylic acids should contain quaternary ammonium groups, or should be derived by reactions from sugar molecules, or are neuraminic acid or N-acetyl neuraminic acid, or derivatives of these.
The novel compounds of the present invention may be prepared in accordance with the following reaction scheme: ##STR4## wherein the Z and the R groups are as hereinabove defined. According to the reaction scheme above, 1,4-Z-diamino-5,8-dihydroxy anthraquinone reacts with the appropriate acid chloride O═C(R)Cl in a solvent such as 2-methoxyethanol at temperatures from about 40° C. to about 55° C. under nitrogen atmosphere for about 10 hours. The solution obtained is filtered. After addition of a sufficient amount of diethyl ether, a precipitate forms. The precipitated product is recrystallized in a water/ethanol system.
This class of compounds have light to dark-blue colored crystals, have characteristic melting points and characteristic absorption spectra. The crystals are soluble in water and in organic solvents like 2-methoxyethanol, but insoluble in diethylether, acetone and ethanol. Through addition of acids, ammonium salts of these series of compounds can be formed, if, for example, the acyl group in the formula contains amino or substituted amino groups.
The use of these compounds will be through the production of medical preparates for parenteral, enteral, oral, cutane or mucosal application with antineoplastic effect.
EXAMPLE 1
1,4-bis-N-carnityl ethylenediamino-5,8-dihydroxyanthraquinone dichloride: 0.712 g (0.002 mol) 1,4-bis-ethylenediamino-5,8-dihydroxyanthraquinone is dissolved in approximately 130 mL 2-methoxyethanol. The solution is stirred in a reactor for 1-2 hours under nitrogen atmosphere at 40° C. and filtered afterwards. 0.8648 g carnitine chloride is added to the filtrate and allowed to stand approximately 12 hours under the same conditions. The mixture is then filtered and 500 mL of diethylether is added to the filtrate and is left for 45 minutes for precipitation. The precipitate is filtered through a glass filter, washed with diethylether, dried at 40° C. and recrystallized from water/ethanol mixture at 4° C. for 12 hours. The product is centrifuged and washed with diethylether and ethanol dried at 40° C. and then in a desiccator over P 2 O 5 overnight. The melting point is 170-173° C. The obtained compound is soluble in water and in 2-methoxyethanol.
According to preliminary in vitro experiments, this compound shows a very strong anti-tumor activity. After a 48-hour treatment of L1210 leukemia cells show 0.59±0.18 μg/mL of this compound the same activity as 6.90±2.28 μg/mL of the standard comparison substance FCE 24517. This demonstrates that the 1,4-bis-(N-carnitinechloride)-ethylenediamino-5,8-dihydroxyanthraquinone dichloride approximately 12 times stronger acts than the standard comparison substance FCE 24517 for the treatment of the leukemia cells L1210.
EXAMPLE 2
1,4-bis-N-(N-trimethylamino acetyl)-ethylenediamino-5,8-dihydroxy anthraquinone dichloride: 0.712 g (0.002 mol) 1,4-bis-ethylenediamino-5,8-dihydroxy anthraquinone is dissolved in 350 mL 2-methoxyethanol under nitrogen atmosphere at 40° C. for an hour. 0.688 g (0.004 mol) acetic acid trimethyl ammonium chloride is immediately added to this solution. The mixture is continuously stirred under nitrogen atmosphere for 24 hours at 40° C. and then filtered through a glass filter. 8mL diethyl ether is added to the solution and it is allowed to stand for 45 minutes. The precipitate is then filtered through a glass filter and dried. It is crystallized from water/absolute ethanol solution at 60° C. in a water bath and finally left in at 4° C. for 12 hours. After three recrystallizations, the melting point was 222-226° C. The product consists of dark blue crystals and is soluble in water and 2-methoxyethanol.
EXAMPLE 3
1,4-bis-N-gluconyl ethylenediamino-5,8-dihydroxy anthraquinone: 120 mL 2-methoxyethanol is added to 0.712 g 1,4-bis-ethylenediamino-5,8-dihydroxyanthraquinone and stirred at 40° C. for about an hour. After filtration, the filtrate is transferred into a reactor. 0.858 g gluconic acid chloride is added to the filtrate. This solution is left for about 12 hours under nitrogen atmosphere at 40° C. After cooling down, 500 mL diethylether is added to the product and after 30 minutes it is filtered through a glass filter, washed with diethylether, and dried at 35° C. in a desiccator over P 2 O 5 for about 12 hours. After three recrystallizations, 1.0 g dark blue crystals are obtained. The melting point is 210-215° C. The obtained compound is soluble in water and in 2-methoxyethanol.
According to preliminary in vitro experiments, this compound shows a very strong anti-tumor activity. After a 48-hour treatment of L1210 leukemia cells show 1.16±0.25 μg/mL of this compound the same activity as 6.90±2.28 μg/mL of the standard comparison substance FCE 24517. This demonstrates that the 1,4-bis-(N-gluconyl)-ethylenediamino-5,8-dihydroxy anthraquinone acts approximately 6 times stronger than the standard comparison substance FCE 24517 for the treatment of the leukemia cells L1210.
Other in-vitro experiments, in particular with leukemia, small cell bronchial carcinoma and renal neoplasm show that a microgram level application of this compound the malignant growth is stopped. A reduction of malignant cells is observed by using higher concentrations.
Experiments with rats showed that the cardiac toxicity of this compound is about one third of the cardiac toxicity of the compound mitoxantrone.
EXAMPLE 4
1,4-bis-N-(2-aminogluconyl)-5,8-dihydroxy anthraquinone: 0.712 g (0.002 mol) 1,4-bis-ethylenediamino-5,8-dihydroxyanthraquinone is dissolved in 350 mL 2-methoxyethanol under nitrogen atmosphere at 40° C. for an hour. 1.4 g (0.004 mol) 2-aminogluconic acid chloride is immediately added to this solution. The mixture is continuously stirred under nitrogen atmosphere for 24 hours at 40° C. and then filtered through a glass filter. 8 mL diethyl ether is added to the solution and it is allowed to stand for 45 minutes. The precipitate formed is then filtered through a glass filter and dried. It is crystallized from water/absolute ethanol solution at 60° C. in a water bath and finally left at 4° C. for 4 hours. The product consists of dark blue crystals and is soluble in water and 2-methoxyethanol.
EXAMPLE 5
1,4-bis-N-acetyl neuraminyl ethylene diamino-5,8-dihydroxy anthraquinone: 130 mL 2-methoxyethanol is added to 0.712 g (0.002 mol) 1,4-bis-ethylenediamine-5,8-dihydroxyanthraquinone, stirred and filtered. The filtrate is transferred into a glass reactor. 1.311 g (0.004 mol) dried N-acetyl neuraminic acid chloride is immediately added to the mixture. The mixture is continuously stirred under the inert nitrogen atmosphere for 48 hours at about 15° C. It is crystallized from water/ethanol solution (1:9 vol. ratio) and is left at 4° C. for 12 hours. The mixture is filtered through a glass filter and dried in a desiccator over phosphorus pentoxide. After recrystallization, the desired product is obtained as dark-blue crystals. M.P. 86-90° C. It is soluble in water and 2-methoxyethanol. | A compound selected from the group having the general formula ##STR1## wherein Z is a divalent moiety selected from linear or branched, saturated or unsaturated alkylene group, and the O═C(R) group contains one of a quaternary ammonium group and a sugar moiety, or the O═C(R) group is part of a neuraminic acid moiety, and their pharmacologically acceptable acid addition salts. Also a medical preparate with antineoplastic effects utilizing such a compound. | 2 |
CROSS-REFERENCE TO RELATED APPLICATION
[0001] The present application claims priority from U.S. Patent Application No. 60/______ entitled “EXTENDED CUTTING BLADES FOR HAND-HELD CUTTING TOOLS,” filed 10 Aug. 2001, and identified by Perkins Coie LLP Docket No. 31957-8010.
TECHNICAL FIELD
[0002] The present invention relates to hand-held cutting tools, such as those used to cut fiber-cement siding.
BACKGROUND
[0003] The exteriors of houses and other types of buildings are commonly covered with siding materials that protect the internal structures from external environmental elements. The siding materials are typically planks or panels composed of wood, concrete, brick, aluminum, stucco, wood composites or fiber-cement composites. Wood siding is popular, but it is costly and flammable. Wood siding also cracks causing unsightly defects, and it is subject to infestation by insects. Aluminum is also popular, but it deforms easily, expands and contracts in extreme climates and is relatively expensive. Brick and stucco are also popular in certain regions of the country, but they are costly and labor intensive to install.
[0004] Fiber-cements siding (FCS) offers several advantages compared to other types of siding materials. FCS is made from a mixture of cement, silica sand, cellulose and a binder. To form FCS siding products, a liquid fiber-cement mixture is pressed and then cured to form FCS planks, panels and boards. FCS is advantageous because it is non-flammable, weather-proof, and relatively inexpensive to manufacture. Moreover, FCS does not rot or become infested by insects. FCS is also advantageous because it may be formed with simulated wood grains or other ornamental designs to enhance the appearance of a building. To install FCS, a siding contractor cuts the panels or planks to a desired length at a particular job site. The siding contractor then abuts one edge of an FCS piece next to another and nails the cut FCS pieces to the structure. After the FCS is installed, trim materials may be attached to the structure and the FCS may be painted.
[0005] Although FCS offers many advantages over other siding materials, it is difficult and expensive to cut. Siding contractors often cut FCS with a circular saw having an abrasive disk. Cutting FCS with an abrasive disk, however, generates large amounts of very fine dust that creates a very unpleasant working environment. Siding contractors also cut FCS with shears having opposing blades, as set forth in U.S. Pat. No. 5,570,678 and U.S. Pat. No. 5,722,386, which are herein incorporated in their entireties by reference. Although the shears set forth in these patents cut a clean edge in FCS without producing dust, many siding contractors prefer to use a hand-held tool because they are accustomed to cutting siding with hand saws. Therefore, in light of the positive characteristics of FCS and the need for a hand-held cutting tool, it would be desirable to develop a hand-held cutting tool that quickly cuts clean edges through FCS without producing dust.
[0006] To meet the demand for a hand-held FCS cutting tool, the present inventors developed a hand-held tool with a reciprocating cutting blade which is the subject of U.S. Pat. No. 5,993,303 (“the '303 patent,” the entirety of which is incorporated herein by reference). The hand-held tool of the '303 patent may have a hand-held motor unit with a housing, a motor inside the housing, and a switch operatively coupled to the motor to selectively activate the motor. A head having a casing may be attached to the housing of the motor unit. The head may also have a reciprocating drive assembly coupled to the motor.
[0007] The hand-held cutting tool of the '303 patent also has a blade set with first and second fingers attached to either the casing or the motor housing, and a reciprocating cutting member between the first and second fingers. The first finger may have a first guide surface and a first interior surface. Similarly, the second finger may have a second guide surface and a second interior surface. The first and second guide surfaces are preferably in a common plane, and the first and second interior surfaces are spaced apart from one another by a gap distance. The reciprocating cutting member of the blade set has a body with a first width approximately equal to the gap distance and a reciprocating blade projecting from the body. The reciprocating blade has a first side surface facing the first interior surface of the first finger, a second side surface facing the second interior surface of the second finger, and a top surface. The first side surface of the blade is preferably spaced apart from the first interior surface of the first finger by 0.040-0.055 inches for cutting ¼ inch and 5/16 inch thick fiber-cement siding. Similarly, the second side surface of the blade is spaced apart from the second interior surface of the second finger by 0.040-0.055 inches. The distance between the first and second side surfaces of the blade and the first and second fingers, respectively, may be approximately 13%-22% of the thickness of the fiber-cement siding workpiece.
[0008] The top surface of the reciprocating blade may also have a width less than the first width of the body. For example, the top surface of the reciprocating blade may be between 0.140 and 0.165 inches, and more preferably between 0.160 and 0.165 inches for cutting ¼ inch and 5/16 inch thick fiber-cement siding. The top surface may also have a curvature concave with respect to the first and second guide surfaces of the first and second fingers.
[0009] In operation, a drive assembly is operatively coupled to the reciprocating member to reciprocate the blade into and out of the gap between the fingers. As the drive assembly moves the blade into the gap between the fingers, the top surface of the blade and the straight guide surfaces of the fingers shear the fiber-cement siding.
[0010] One drawback of the hand-held tool of the '303 patent, however, is that the fingers can be worn away relatively quickly in cutting the abrasive FCS. If the fingers are worn, the edge of the finger may not cleanly break the surface of the FCS or the spacing between the reciprocating blade and the fingers can fall outside desirable tolerances. FCS is a relatively brittle material that tends to crack along rough edges and unpredictable paths. Excessive wear of the shear edge and/or the interior surface of a finger can lead to unacceptable cutting of the FCS.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is an isometric view of a hand-held cutting tool and a blade set in accordance with one embodiment of the invention.
[0012] FIG. 2 is a rear isometric view of a casing and blade set in accordance with an embodiment of the invention.
[0013] FIG. 3 is a front isometric view of the casing and blade set of FIG. 2 .
[0014] FIG. 4A is a bottom elevational view of one blade of the blade set of FIGS. 1-3 .
[0015] FIG. 4B is a side elevational view of the blade of FIG. 4A .
[0016] FIG. 4C is a bottom isometric view of the blade of FIG. 4A .
[0017] FIG. 5A is a bottom elevational view of a blade in accordance with another embodiment of the invention.
[0018] FIG. 5B is a side elevational view of the blade of FIG. 5A .
[0019] FIG. 5C is a bottom isometric view of the blade of FIG. 5A .
[0020] FIG. 6 is a side isometric view of a casing and blade set in accordance with an embodiment of the invention utilizing a pair of the blades shown in FIGS. 5A-5C .
DETAILED DESCRIPTION
[0021] Various embodiments of the present invention provide cutting heads and blades for hand-held cutting tools and methods of reconfiguring a cutting head for a hand-held cutting tool. The following description provides specific details of certain embodiments of the invention illustrated in the drawings to provide a thorough understanding of those embodiments. It should be recognized, however, that the present invention can be reflected in additional embodiments and the invention may be practiced without some of the details in the following description.
[0022] FIG. 1 is an isometric view of a hand-held cutting tool 10 for cutting a workpiece W, which may comprise FCS. The cutting tool 10 has a motor unit 20 with a housing 22 , a motor 24 (shown schematically in phantom) inside the housing 22 , and a switch 26 operatively coupled to the motor 24 . The housing 22 preferably has a handle 27 configured to be gripped by an operator. One suitable motor unit 20 is the No. 3208-90 electric motor unit manufactured by Black and Decker Corporation. Another suitable motor unit 20 is the No. 7802 pneumatic motor unit manufactured by Ingersoll-Rand Corporation.
[0023] The output of the motor unit 20 may be converted into a reciprocal motion with a head 30 having a casing 32 and a reciprocating drive assembly 36 (shown schematically in phantom). The casing 32 is attached to the housing 22 of the motor unit 20 . Additionally, the reciprocating drive assembly 36 is coupled to the motor 24 via a gear assembly 38 (shown schematically in phantom) to translate the rotational output from the motor unit 20 into a reciprocating motion. A suitable head 30 is the shear head manufactured by Kett Tool Co., as set forth in U.S. Pat. No. 4,173,069, entitled “Power Shear Head,” which is herein incorporated by reference.
[0024] The cutting tool 10 may also have a blade set 50 with a first blade 60 a attached to one side of the head 30 , a second blade 60 b attached to another side of the head 30 , and a cutting member 90 between the first and second blades 60 a and 60 b. The first and second blades 60 a and 60 b are preferably attached to the head 30 to space the blades 60 a - b from one another by a gap 66 in which the cutting member 90 may be received. In the illustrated embodiment, the blades 60 a - b are attached to the casing 32 . The casing 32 may include a pair of spaced-apart flanges 40 a and 40 b which define a support of the casing.
[0025] FIGS. 2 and 3 are perspective views of the blade set 50 used with the hand-held cutting tool 10 . The cutting member 90 may have a body 91 with a first width approximately equal to a gap distance G between the first shear face 62 a of the first blade 60 a and the first shear face 62 b of the second blade 60 b . The cutting member 90 may also have reciprocating blade 92 projecting from the body 91 between the first and second blades 60 a and 60 b . The reciprocating blade 92 has a first side surface 94 facing the first blade 60 a , a second side surface 95 facing the second blade 60 b , and a curved top surface 96 . The edge along the top surface 96 and the first side surface 94 defines a first cutting edge 97 of the reciprocating blade 92 , and the edge along the top surface 96 and the second side surface 95 defines a second cutting edge 98 of the reciprocating blade 92 .
[0026] FIGS. 4 A-C illustrate a blade 60 in accordance with one embodiment of the invention. The first blade 60 a and the second blade 60 b shown in FIGS. 1-3 may be identical. Only one blade 60 is shown in FIGS. 4 A-C, but it should be understood that the first and second blades 60 a - b of FIGS. 1-3 may have the same structure shown in FIGS. 4 A-C.
[0027] The blade 60 has a body 61 . The body includes a first shear face 62 and a second shear face 64 . The first and second shear faces 62 and 64 may be substantially planar and parallel to one another. The first and second shear faces 62 and 64 are spaced from one another to define a thickness of the body 61 . A guide surface 80 extends between the first and second shear faces 62 and 64 along a first elongate edge of the body 61 . A first shear edge 82 is defined at the junction between the guide surface 80 and the first shear face 62 . A second shear edge 84 is defined at the junction between the guide surface 80 and the second shear face 64 . The first and second shear edges 82 and 84 may be parallel to one another and spaced from one another by the thickness of the body 61 .
[0028] As noted above, the blade 60 may be carried by the casing 32 of the housing 30 . The blade 60 may be attached to the casing 32 in at least two different operative orientations, with a first mount 70 a mating with the casing 32 to orient the blade in a first operative orientation and a second mount 70 b used to mount the blade 60 in a second operative orientation. In the illustrated embodiment, the first mount 70 a comprises a first pair of mounting holes passing through the thickness of the body 61 and the second mount 70 b comprises a second pair of mounting holes passing through the thickness of the body 61 . In particular, the blade 60 has a central mounting hole 66 , which may be disposed generally midway along the length of the blade 60 . A first outer mounting hole 68 is spaced a fixed mounting distance D from the central mounting hole 66 in a first direction and a second outer mounting hole 69 is spaced the same fixed mounting distance D from the central mounting hole 66 in a second direction.
[0029] In the illustrated embodiment, the central mounting hole 66 is shared by the first and second mounts 70 a - b . Hence, the first mount 70 a includes the central mounting hole 66 and the first outer mounting hole 68 , whereas the second mount 70 b includes the central mounting hole 66 and the second outer mounting hole 69 . If so desired, more than three mounting holes may be employed. In such a circumstance, the first mount 70 a may comprise two of these mounting holes while the second mount 70 b may comprise two different mounting holes.
[0030] The mounting distance D is selected to coincide with the distance D between a pair of spaced-apart mounting rods 42 and 44 (best seen in FIG. 1 ). The first mounting rod 42 may pass through the central mounting hole 66 and the second mounting rod 44 may pass through the first outer mounting hole 68 or the second outer mounting hole 69 , depending on the operative orientation of the blade 60 .
[0031] The blade 60 of FIGS. 4 A-C illustrate mounting holes 66 , 68 and 69 which pass through the thickness of the body 61 . It should be understood, though, that the mounting holes 66 , 68 and 69 could instead be replaced with mounting points bearing the same spatial relationship as the illustrated mounting holes. Such a mounting point may, for example, comprise a recess (not shown) or protrusion (not shown) carried by one or both of the shear faces 62 and 64 . The casing 32 of the housing 30 may be adapted to mate with such recesses or protrusions to fix the position of the blade 60 in one of the desired operative orientations.
[0032] FIGS. 2 and 3 illustrate the first blade 60 a and the second blade 60 b carried by the housing 30 . In particular, the first mounting rod 42 passes through the support flanges 40 a - b , through the central mounting hole 66 of each of the blades 60 a - b , and through the body 91 of the cutting member 90 . The first mounting rod 42 may define an axis about which the cutting member 90 may pivot when reciprocating. The second mounting rod 44 passes through the first outer mounting holes 68 (not visible in FIGS. 2 and 3 ) of each of the blades 60 a - b . Hence, each of the blades 60 a - b is mounted to the casing 32 via its first mount ( 70 a in FIGS. 4 A-C). The second outer mounting hole 69 is disposed distally of the casing 32 .
[0033] The first shear face 62 a of the first blade 60 a and the first shear face 62 b of the second blade 60 b are oriented toward one another and are positioned adjacent the cutting member 90 . The second shear face 64 a of the first blade 60 a abuts the first support flange 40 a of the casing 32 and may lie flush against the inner surface of the first support flange 40 a . The second shear face 64 b of the second blade 60 b may also be oriented outwardly away from the cutting member 90 and be mounted flush against an inner surface of the second support flange 40 b of the casing 32 .
[0034] With the blades 60 a - b mounted in this fashion, the first shear edges 82 a - b of the blades 60 a - b are positioned to cooperate with the cutting member 90 to shear the workpiece W. This relative positioning of the first shear edges 82 a - b with respect to the reciprocating cutting member 90 is achieved by the fixed spacing and orientation of the first shear edge 82 of each blade 60 with respect to the first pair of mounting holes 70 a . This is illustrated in FIG. 4B by noting that the central mounting hole 66 is spaced a distance S 1 from the first shear edge 82 and the first outer mounting hole 68 is space a distance S 2 from the first shear edge 82 . The distances S 1 and S 2 may be the same or they may differ from one another.
[0035] FIG. 4B indicates that the second outer mounting hole 69 is also spaced the same distance S 2 from the guide surface 80 of the blade 60 . As a consequence, the orientation and spacing of the second shear edge 84 of the blade 60 with respect to the second mount 70 b is the same spacing and orientation between the first mount 70 a and the first shear edge 82 . This allows the blade to be reoriented on the head 30 to position the second shear edge 84 adjacent to the reciprocating cutting member 90 for cooperation therewith to cut a workpiece W simply by switching from the first mount 70 a to the second mount 70 b.
[0036] When the cutting edge of a finger of the hand-held FCS cutting tool of the '303 patent becomes dull or the facing surface of the finger becomes too worn, the finger is commonly replaced with a new finger. Given the strength and abrasion-resistant requirements of such a finger, though, the finger can be fairly expensive. The effective life of a blade 60 in accordance with the embodiment of FIGS. 1-4 is effectively double the total life of one of the fingers used in connection with the tool of the '303 patent. When the first shear edge 82 of the blade 60 becomes dull, the blade 60 can be detached from the casing 32 . Rather than disposing of the blade 60 , the blade can be flipped lengthwise to position the second outer mounting hole 69 to receive the second mounting rod 44 therethrough. This orients the first shear face 62 outwardly into abutment with the casing 32 and spaces the first shear edge 82 transversely outwardly from the cutting member 90 . Mounting the blade in this position also orients the second shear face 64 inwardly toward the cutting member 90 and positions the second shear edge 84 adjacent the reciprocating blade 92 to cooperate with the cutting member 90 to cut a workpiece W. The second shear edge 84 was previously spaced transversely outwardly from the cutting member 90 when the cutting member 90 sheared the workpiece W with the first shear edge 82 . As a result, the second shear edge 84 will remain sharp and ready for use even if the blade 60 has already been used to cut a number of workpieces W using the first shear edge 82 . FIGS. 5-6 illustrate an alternative embodiment of the invention. The blade 60 of FIGS. 1-4 effectively doubles the useful life of the blade by providing a pair of shear edges 82 and 84 , each of which can be selectively positioned adjacent the reciprocating cutting member 90 to shear a workpiece W. The blade 160 of FIGS. 5-6 effectively quadruples the life of a single blade by providing four spaced-apart shear edges 182 , 184 , 186 , and 188 , each of which can be positioned to cut a workpiece with the cutting member 90 .
[0037] Much like the blade 60 of FIGS. 4 A-C, the blade 160 of FIGS. 5 A-C has a first shear face 162 and a second shear face 164 . The shear faces 162 and 164 are spaced from one another to define a thickness of the body 161 . A first guide surface 180 extends between the first and second shear faces 162 and 164 along a first elongate edge of the body 161 . A second guide surface 181 extends between the first and second shear faces along a second elongate edge of the body 161 . The first and second guide surfaces 180 and 181 may be generally parallel to one another, as shown. A first shear edge 182 is defined at the junction between the first guide surface 180 and the first shear face 162 . A second shear edge 184 is defined at the junction between the first guide surface 180 and the second shear face 164 . A third shear edge 186 is defined at the junction between the second guide surface 181 and the first shear face 162 . A fourth shear edge 188 is defined at the junction between the second guide surface 181 and the second shear face 164 .
[0038] The blade 160 has at least five mounting points by which the blade 160 can be mounted to the housing 30 of the hand-held tool 10 . These mounting points are typified in the drawings as mounting holes which pass through the thickness of the body 161 . In an alternative embodiment, the mounting points may comprise protrusions or recesses in the faces 162 and 164 of the blade 160 , much as noted above in connection with the blade 60 .
[0039] The blade 160 may include at least one central mounting hole 166 , a first outer mounting hole 168 , a second outer mounting hole 169 , a third outer mounting hole 178 , and a fourth outer mounting hole 179 . If a single central mounting hole 166 is employed, each of the outer mounting holes 168 , 169 , 178 , and 179 may be spaced the same fixed mounting distance D from the central mounting hole 166 . In the illustrated embodiment, the blade 160 includes two central mounting holes. The first central mounting hole 166 is spaced the fixed mounting distance D from the first outer mounting hole 168 and from the second outer mounting hole 169 . A second central mounting hole 176 is spaced the same mounting distance D from the third outer mounting hole 178 and the fourth outer mounting hole 179 .
[0040] The first central mounting hole 166 and the first outer mounting hole 168 define a first pair of mounting holes 170 a . The first central mounting hole 166 and the second outer mounting hole 169 define a second pair 170 b of mounting holes. The second central mounting hole 176 and the third outer mounting hole 178 define a third pair 170 c of mounting holes. The second central mounting hole 176 and the fourth outer mounting hole 179 define a fourth pair 170 d of mounting holes.
[0041] FIG. 6 illustrates a first blade 160 a and a second blade 160 b attached to the casing 32 of the housing 30 . Each of the blades 160 a - b is attached to the casing 32 via the first pair ( 170 a in FIG. 5B ) of mounting holes by passing the first and second mounting rods 42 and 44 therethrough. This orients the first shear edge 182 a of the first blade 160 a and the first shear edge 182 b of the second blade 160 b adjacent the cutting member 90 to cut a workpiece W.
[0042] Because the mounting holes of each pair 170 are spaced from one another the same mounting distance D, the blade 160 can be reoriented in four different operative orientations by passing the mounting rods 42 and 44 through different pairs 170 of mounting holes in the blade 160 . Each of the pairs 170 of mounting holes is spaced a fixed distance from and has a fixed orientation with respect to an associated one of the shear edges. In particular, the first pair 170 a of mounting holes is associated with the first shear edge 182 , the second pair 170 b of mounting holes is associated with the second shear edge 184 , the third pair 170 c of mounting holes is associated with the third shear edge 186 , and the fourth pair 170 d of mounting holes is associated with the fourth shear edge 188 . By attaching the blade 160 to the casing 32 with the mounting rods 42 and 44 extending through any one of the four pairs 170 of mounting holes, the shear edge associated with the selected pair of mounting holes will be positioned to cooperate with the cutting member 90 to shear a workpiece W. As a consequence, by simply flipping the blades 160 a and 160 b to different operative orientations with respect to the casing 32 , each blade 160 a - b can provide four different shear edges for cutting workpieces W. This effectively quadruples the life of the blades.
[0043] Another embodiment of the invention provides a method of reconfiguring a cutting head for a hand-held cutting tool such as the cutting tool 10 shown in FIG. 1 , though other designs (including, but not limited to, the embodiment of FIGS. 5-6 ) may be employed instead. In a first operative orientation of the blades 60 a and 60 b , the first shear edge 62 of each blade is positioned adjacent the reciprocating cutting member 90 for cooperation therewith and the second shear edge 64 of each blade 60 is spaced transversely outwardly of both the reciprocating cutting member 90 and the first shear edge 62 . In one method of the invention, the first mount 70 a of the first blade 60 a is detached from the casing 32 . The body 61 of the first blade 60 a is turned and the second mount 70 b of the first blade 60 b is mated to the casing 32 to attach the first blade 60 to the casing 32 in a second operative orientation. In this second operative orientation, the second shear edge 64 a of the first blade 60 a is positioned adjacent the reciprocating cutting member 90 for shearing a workpiece W and the first shear edge 62 of the first blade 60 is positioned transversely outwardly of both the reciprocating cutting member 90 and the second shear edge of the first blade. Much the same process can be used to reorient the second blade 60 b to position its second shear edge 64 b adjacent the cutting member 90 .
[0044] From the foregoing, it will be appreciated that specific embodiments of the invention have been described herein for purposes of illustration, but that 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. | An extended-life cutting blade is adapted for mounting on a hand-held cutting tool in multiple operative orientations. A single cutting blade may provide up to four independent shear edges, each of which has a useful life. The blade can be easily changed from an orientation adapted to cut a workpiece with one shear edge to a different operative orientation adapted to cut with a different shear edge by selecting an appropriate mount on the blade. | 1 |
CROSS REFERENCE TO RELATED APPLICATIONS
This application is a continuation-in-part of U.S. Ser. No. 07/850,586, filed Mar. 13, 1992 now abondoned.
FIELD OF THE INVENTION
The present invention relates generally to the field of immunology, and particularly to a polypeptide factor which stimulates or regulates the proliferation and differentiation of lymphocyte and other hematopoietic progenitors and which enhances the response of animals to infectious agents and to malignancies.
BACKGROUND OF THE INVENTION
The function of the thymus gland, which lies just beneath the breast bone, was only first revealed in 1960. Prior to that time, the thymus was thought to be of little importance since in adults it is almost non-existent because of rapid atrophy after adolescence. As was the case with other organs (e.g., the pancreas), the function of the thymus was suggested by observing the effect of its removal in young animals. When pre-adolescent animals are thymectomized, they experience a profound "wasting disease" which is characterized by a variety of maladies, including increased incidence of infection and cancer, failure to grow, allergies and neuromuscular paralysis. The greater susceptibility to infection and cancer was shown to be directly attributable to a dramatic decrease in peripheral blood lymphocytes, and could be prevented by rearing the animal in a germ-free environment. However, the other symptoms of thymectomy were not completed abrogated by this approach.
In 1964, it was demonstrated that hormone-like factors from thymus tissue could prevent many of the manifestations of "wasting disease," thus suggesting that the thymus produces substances important in the development of immunity. The relationship of this observation to the other "wasting disease" symptoms was not well understood at that time, however.
B and T lymphocytes are the primary effector cells of the immune response. Both cell classes are considered to derive ultimately from hematopoietic stem cells in the mammalian bone marrow, via progenitor or precursor cells representing distinguishable stages in the differentiation of each class. B lymphocytes, or B cells, are the precursors of circulating antibody-secreting plasma cells. Mature B cells, which are characterized by expression of surface-bound immunoglobulin capable of binding specific antigens, derive from hematopoietic stem cells via an intermediary cell class known as pre-B cells. Mature T cells develop principally in the thymus, presumably from an as yet unidentified precursor cell which migrates from the bone marrow to the thymus at an early stage of T lymphocyte development.
It was not until 1971 that it was discovered that the thymus-derived lymphocytes (T cells) regulated the reactivity of bone marrow-derived antibody-producing lymphocytes (B cells). The latter are involved in the pathogenesis of many autoimmune-type diseases, i.e., those involving the body's reactivity to its own cells or tissues. Examples of such diseases include arthritis, multiple sclerosis, muscular dystrophy, lupus erythematosus, and quite possibly juvenile onset diabetes. Many of the problems associated with "wasting disease" in thymectomized animals are similar to "autoimmune-type" disease. In general, when the thymus gland fails to function properly, T cells, which control the immune response, are defective or absent and the system breaks down.
After the discovery that the thymus was producing a hormone-like factor, several groups of scientists began trying to extract and purify the material from thymus glands, or from serum, in much the same manner that insulin was prepared for therapeutic use in diabetes. The difficulty is that the thymus produces very small quantities of the hormone or hormones. Thus, one requires large amounts of calf thymus or several liters of serum to biochemically extract small amounts of active material. Success has been very limited with this approach.
Very little is known about regulatory factors involved in B and T cell lymphogenesis. In particular, all the factors or conditions required for commitment and expansion of the B and T cell lineages have not yet been defined, albeit it is now known that one or more thymic factors or hormones are produced by the epithelial cells of the thymus gland. (See, e.g., Waksal, et al., Ann. N.Y. Acad. Sci. 249: 493 (1975).) While the ideal approach for studying these factors or hormones would be to isolate these cells from fresh thymic tissue and grow them in vitro, epithelial cells have been extremely difficult to maintain in continuous culture in the laboratory.
Recently, this technical barrier has been overcome, with the presently-disclosed establishment of cloned lines of thymic epithelial cells of feline, canine, bovine and human origin. Earlier efforts to establish a cloned cell line of murine origin laid some of the procedural groundwork for the present invention. (See Beardsley, et al., PNAS 80: 6005 (1983), and Hays & Beardsley, Clin. Immunol. Immunopath. 33: 381 (1984), which are incorporated herein by reference). The present disclosure demonstrates that the thymic epithelial cell lines of the present invention are, in fact, producing factors having activity similar but not identical to substances previously obtained by the difficult and labor-intensive procedure of extracting thymic substances from calf thymus; however, the presently-disclosed factor is in a much purer and more homogeneous form, is produced in greater quantities and has a different and distinct mechanism of action.
The primary activity of the cloned thymic epithelial cell factors produced according to the presently disclosed method has been shown to have the capacity to augment the immune responses of both immature and mature T cells. This factor, which shall be referred to herein as T4 immune stimulating factor ("TISF"), is being further purified and characterized biochemically. Also, in vivo studies have been initiated to determine the efficacy of TISF in enhancing the response of animals to infectious agents and to malignant cells.
Although much of the work done to date has focused on the murine and canine models, the implications and applications to other animals, e.g., felines, bovine species, and especially to humans, have been shown to be equally relevant. As disclosed herein, the difficult step of establishing a human epithelial cell line has also been accomplished successfully. One immediate goal is to apply the various aspects of the present invention, especially TISF, to produce an effective immune potentiator and/or therapeutic agent for the treatment of immunologically-related disease and to produce agents useful in immunization against etiologic agents of disease.
SUMMARY OF THE INVENTION
In one embodiment of the present invention, there is provided a substantially homogeneous thymus-derived factor expressed by a cloned thymic epithelial cell line, having a molecular weight of about 50,000 daltons, an isoelectric point of about 6.5, and capable of inducing or enhancing cell-mediated immune responsiveness of mature T-cells in mammalian organisms. In an alternative embodiment, the factor comprises one or more polypeptides substantially free of any additional endogenous materials. Preferably, the factor is of feline, canine or bovine origin; most preferably, it is of human origin. In another variation, the factor has the ability to enhance the response of animals to infectious agents.
In another embodiment, a thymus-derived factor according to the present invention has the ability to enhance the response of mammalian organisms to malignant cells. In alternative variations, the mammalian organisms are felines or canines; in preferred embodiments, the mammals are humans.
The present invention also discloses a composition comprising an effective, immune-responsiveness-enhancing amount of thymus-derived factor incorporated in a pharmaceutically acceptable carrier or excipient. In one alternative embodiment, the composition is capable of providing therapeutic benefits in immunocompromised mammalian organisms. Compositions according to the present invention may be provided in a form suitable for parenteral administration, intraperitoneal administration, topical administration or oral administration.
In other embodiments, methods for treating infections in a mammalian organism comprising administering to the organism an effective amount of thymic factor or composition containing the factor is disclosed. In other variations, the infection is caused by a virus. Preferably, the virus is a retrovirus, Feline Immunodeficiency Virus, rabies virus, distemper virus or Human Immunodeficiency Virus. Advantageously, the mammalian organism is either a feline or canine; most advantageously the organism is a human.
In other variations, the compound is administered parenterally, intraperitoneally, after being incorporated within liposomes, topically or orally.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1A illustrates the isolation of LYT-2 negative and L3T4 negative cell populations.
FIG. 1B illustrates the effect of TISF on the LYT-2 negative population.
FIG. 1C illustrates the lack of activity in cultures without L3T4 positive helper cells.
FIG. 2A illustrates blocking of TISF enhancement of cytotoxic killer activity by antibody directed against the IL2 receptor (7D4 or 3C7).
FIG. 2B illustrates that irrelevant antibodies lack a blocking effect.
FIG. 3 illustrates TISF enhancement of antibody responses to rabies virus.
FIG. 4 illustrates survival data in a model used to test the efficacy of TISF in dogs immunized with distemper virus adjuvanted with either alum or TISF and then challenged with a virulent strain of distemper virus.
FIG. 5 illustrates the enhancement of killing activity via a test for secondary cytotoxic killer cell response against target cells infected with influenza virus.
FIG. 6 illustrates the effect of TISF in cats infected with Feline Immunodeficiency Virus.
DETAILED DESCRIPTION OF THE INVENTION
As used in the present disclosure, "TISF" refers to a mammalian polypeptide or mixture of polypeptides which are capable of stimulating or regulating the proliferation and differentiation of lymphocyte and other hematopoietic progenitors, including T cell precursors. TISF has its greatest effect in enhancing the response of mature T lymphocytes to infectious agents and to malignant cells.
The primary criterion of effectiveness of the derived factor is its ability to induce immune function in a population of cells which do not function without that induction. Thymocytes are comprised of immature cells which are non-functional and mature T cells which can be stimulated to function against various agents such as viruses and tumors. Originally, this immature cell population was used to test the factor from thymic epithelial cell cultures. As documented in Beardsley, et al., PNAS 80: 6005 (1983), the murine thymic cell factor can induce a very substantial immune response in a population of cells that are normally unresponsive. While TISF has a slight but recognizable stimulatory effect on these immature cells, its primary action is directed toward the mature T lymphocyte, resulting in increased viral or tumor immunity. We have distinguished TISF from IL-2 or IL-1, which can have similar, but less dramatic effects. The major difference is that thymocytes only need to be pulsed with TISF for 24 hours, whereas IL-2 must be present throughout the 5day induction phase of the response. TISF has as the primary target of its stimulatory action the unresponsive mature T lymphocyte.
It has now been demonstrated that TISF is promoting the response of a helper cell population. FIG. 1B demonstrates that TISF is affecting the LYT-2 negative population. Conversely, cultures devoid of L3T4 positive helper cells (FIG. 1C) have no activity.
TISF can greatly enhance or potentiate both antibody-mediated or killer cell responses against infectious agents and/or cancer via its effect on IL-2 producing cells. The tremendous effect of TISF has been shown to be due to its ability to stimulate IL-2 production. This is shown in FIG. 2A by the blocking of TISF enhancement of cytotoxic killer activity by antibody directed against the IL-2 receptor (7D4 or 3C7). Irrelevant antibodies have no blocking effect (FIG. 2B). From a therapeutic standpoint, it makes sense to recruit the helper cells to make IL-2 at the site where they are required, rather than inject a bolus of IL-2 which is rapidly diluted and degraded in body fluid.
Several companies have attempted to demonstrate the effectiveness of IL-2, both as a therapeutic and an adjuvant. The problems are at least two-fold. First, IL-2 is a local, short-acting cytokine. To achieve physiologic levels at the desired site, i.e., a tumor mass, unnaturally large doses must be administered. Thus, the likelihood of the patient suffering from side-effects is dramatically increased. Second, IL-2 must be present continuously for at least five days in order to induce an effective response.
From a practical as well as an economic point of view, IL-2 therapy is logistically difficult and very expensive. Twice-daily injections of IL-2 over a period of five days in a hospital setting would cost over $1,000 just for the drug alone.
In contrast, a substance similar to that which we call TISF is normally present in the blood in physiologically measurable levels, except in certain disease states. Its mode of action is widespread on cells of the immune system throughout the body. Since it is a normal constituent in the circulation, few, if any, side-effects would be expected. However, the greatest advantage is that a single injection of TISF has long-lasting effects and could be self-administered much like insulin, only less frequently. Therefore, patient and physician convenience, plus the relatively reduced cost, would enhance clinical acceptance.
TISF may be subjected to a series of purification steps in order to obtain an extract with higher degrees of purity. For example, in Table 1, the use of purification methods such as an AX 300 column (anion exchange beads) or a CM 300 column (cation exchange beads) is illustrated. An overall TISF purification of greater than 200 fold was obtained from a crude thymic cell culture supernatant.
TABLE I__________________________________________________________________________Purification of TISF factor. Volume Protein Total Units Total % Specific Fold-Material (ml) (μg/ml) Protein /ml.sup.a Units Recovery Activity Purification__________________________________________________________________________Crude SN.sup.b 400 50 20.sup.c 10 4000 100 200 1AX 300 10 100 1.sup.d 200 2000 50 2,000 10CM 300 5 12 0.06 200 1000 50 16,700 83C4.sup.e 2 4.5 0.009 100 400 20 44,400 222__________________________________________________________________________ .sup.a The number of units/ml of activity is functionally defined as the inverse of the maximum dilution of sample which still yields at least 90% of the maximal stimulation of the CTL (cytotoxic T lymphocyte) response t alloantigen. Such a definition insured a strong signal and provided excellent consistency between assays. .sup.b Initial volume of TISF culture supernatant (SN) collected under serum free conditions. .sup.c Protein concentration was determined by bradford protein assay (BioRad Laboratories, Richmond, CA). .sup.d Protein concentration was determined from HPLC optical density trace using known standards. .sup.e Material from the AX 300 column that has not been fractionated on the CM 300 column.
Polyacrylamide gel analysis under non-reducing conditions demonstrates that TISF appears as a substantially homogeneous fraction with a major band flanked by two minor bands. Sequence analysis of the TISF fractions is expected to confirm the homogeneity of the fraction produced by the cloned thymic cell lines disclosed herein.
It has been determined that TISF is not any of the previously described cytokines. As previously discussed, TISF is not IL-1 or IL-2. Further testing has also demonstrated that TISF is not IL-4 (see Table 2). This was determined by incubating natural killer (NK) cells with either IL-4 or TISF purified from the culture supernatant and measuring the incorporation of [ 125 I]-deoxyuridine into RNA. As the Table indicates, IL-4 treatment resulted in a significant increase in incorporation of the label, whereas TISF treatment had no effect.
TABLE II__________________________________________________________________________Differences between unfractionated TISF SN and IL-4No Additional of IL-4.sup.AFactorIl-4 Addition 3 U/ml 1 U/ml 0.3 U/ml__________________________________________________________________________None 160 (141-181).sup.b 5278 (4696-5932) 3928 (3538-4361) 2212 (2158-2300)TISF SN10% 171 (161-182) 4498 (3296-6138) 2823 (2803-2842) 1876 (1850-1903) 3% 172 (145-204) 4186 (3735-6138) 3163 (3086-3243) 2103 (2049-2159) 1% 203 (162-255) 4728 (4612-4847) 3267 (3080-3464) 2169 (2002-2350) 0.3%159 (143-177) 4449 (4255-4652) 3417 (3234-3611) 2425 (2362-2546)__________________________________________________________________________ .sup.a Purified IL4 .sup.b Results are expressed as mean .sup.125 IUdR cpm/culture, followed by the ±1 standard deviation range in parentheses. cultures contained × 10.sup.3 NK cells per cell.
In addition, we have determined that TISF contains no IL-5 or granulocyte-macrophage colony stimulating factor (GM-CSF), as shown in Table 3. The fact that TISF does not have any direct stimulatory activity for B cells would suggest that it is also not IL-3, IL-6 or IL-7. Further purification and genetic cloning are in progress to specifically identify the detailed molecular characteristics of TISF.
TABLE III__________________________________________________________________________TISF SN contains no IL-5 or GM-CSF activity GM-CSF Assay.sup.bFactor IL-5 Assay.sup.a 3.0% addition of No GM-CSF Addition of.sup.dadded No IL-5 Addition purified IL-5.sup.c Addition 1 U/ml GM-CSF__________________________________________________________________________None 467 (372-588).sup.e 3532 (3336-3739) 6 (3-12).sup.e 830 (779-884)UnfractionatedTISF SN10% 212 (201-224) 2193 (1976-2434) 24 (19-31) 688 (661-717) 3% 267 (251-284) 3154 (2556-3890) 24 (19-30) 674 (630-722) 1% 236 (271-258) 3392 (2678-4295) 35 (34-36) 668 (630-708)Partiallypurified 3% 300 (256-351) 3003 (2546-3542) 17 (8-33) 834 (804-866)__________________________________________________________________________ .sup.a IL-5 activity was determined by using the B cell lymphoma BCL1 (ATCC, Rockville, MD). .sup.b GMCSF activity was determined using the DA3 line (ATCC, Rockville, MD). .sup.c IL5 was purified from the culture SN of the D10.G4.1 Th2 cell line as described by McKenzie et al. (J. Immunol. 139: 2661 (1987). The preparation used in these experiments contained approximately 500 units/ml. .sup.d Purified GMCSF purchased from Genzyme Corp. (Cambridge, Mass.). .sup.e The results are expressed as mean .sup.125 IUdR cpm/culture, followed by the 95% confidence interval in parentheses. .sup.f Pooled active fractions from the Sepharose S cation exchange colum (Pharmacia, Piscataway, NJ), as detailed in the product manual.
A cloned cell line of thymic cells may be established as described herein. For example, in accordance with the present invention, thymic stromal cells of feline origin were established as a continuously replicating, cloned cell line, according to the method described in Beardsley, et al., PNAS 80: 6005 (1983), which is incorporated herein by reference. A selection process was used to isolate a cell line producing homogenous TISF.
The same technique has been employed to establish cloned thymic epithelial cell lines from thymic tissue removed from juvenile dogs and calves and from human thymic remnants removed from children undergoing cardiac surgery.
Preparation of Thymic Cell Lines
Briefly, the procedure for reproducibly obtaining the cell lines of the present invention is as follows. Thymus tissue was removed aseptically under general anesthesia. The tissue removed was placed immediately into tissue culture. A primary culture of about 1×10 8 thymocytes was established in a 60 mm Petri dish in 5 ml of DMEM and 20% fetal calf serum. After about 48 hours, the thymocytes were gently washed away and the scattered few adherent cells were fed with 50% fresh DMEM containing 20% fetal calf serum and 50% conditioned medium, obtained after centrifugation of the thymocytes. Primary cultures containing a variety of cell types were maintained by weekly feeding with a similar 50:50 mixture of fresh and conditioned medium. After about four weeks, several isolated colonies of epithelial-like cells covered the plate. At this time, a secondary culture was made by transfer of several of these colonies scraped from the primary culture. Growth tended to be slow until the third subculture, when cells began to form a monolayer within 4-5 days. Cloning of the cells by limiting dilution at one cell per well was less successful than "seeding" the wells with three or four individual cells, which tended to grow to confluency. Single cells plated in limiting dilution were more likely to grow to confluency if epidermal growth factor was added at 6 ng/ml to wells containing single cells.
Clones exhibiting epithelial-like morphology were grown out and the supernatants tested for their ability to enhance alloreactivity in whole thymocyte populations. Supernatants from confluent thymus-derived cultures were tested for their capacity to promote thymocyte functional activity. For example, one such method involved testing the ability of the supernatant to augment the cytotoxic T lymphocyte (CTL) response of thymocytes to allogenic major histocompatibility complex (MHC) antigen. Supernatants exhibiting the capacity to induce or enhance cell-mediated immune responsiveness were preferentially selected for testing and further purification.
Cells are preferably propagated in Dulbecco's minimal essential medium (DMEM) high glucose formulation (Irvine Scientific, Santa Ana, Calif.), supplemented with L-glutamine and one or more appropriate antibiotics (i.e., penicillin G 100 IU/ml; streptomycin 100 μg/ml). The medium may further be supplemented with 1-10% fetal bovine serum or proven serum-free substitute (e.g. Serxtend™, Irvine Scientific, Santa Ana, Calif.). Maintenance medium is made as noted above, without the serum.
The cell cultures may be propagated and maintained according to known methods. Those used in the present invention were propagated in an artificial capillary bed (hollow fiber bioreactor) according to the method described in Knazek and Gullino, Tissue Culture Methods and Applications, Chp. 7, p. 321 et seq., Kruse and Patterson, eds., Academic Press, N.Y., 1973, which is incorporated herein by reference. Another means of propagating and maintaining a cell line is via weekly passage and growth in DMEM and 10% fetal calf serum. The growth medium may be removed from 5-day cultures and replaced with serum-free DMEM for 24 hours. The 24-hour supernatant is useful as the source of thymic factor. A cloned feline cell line in accordance with the present invention is permanently maintained by the inventor under the designation Fe2F, a canine cell line is permanently maintained under the designation Ca-9, a bovine cell line is permanently maintained under the designation TF4, and a human cell line is permanently maintained under the designation HU1.
In a preferred embodiment, as illustrated by the following examples, thymic stromal cell-derived TISF is produced by type II epithelial cells. Cloned cells from a primary culture of thymic tissue are selected initially on the basis of morphology (sere Beardsley, et al., PNAS 80: 6005 (1983), for example, for a description of desired morphological characteristics). Secondarily, cloned lines are selected on the basis of production of TISF, as determined by known in vivo or in vitro bioassay procedures. Purity of the cultures is maintained via regular monitoring for invasive organisms including viruses, bacteria, and fungi.
Purification of Thymic Factor
The TISF is a strongly cationic glycoprotein, and may be purified with cation exchange resin. Purification of the supernatants selected (see, e.g., Table I) produced a substantially homogeneous factor (TISF). Using known assay techniques as described above, it is now apparent that the effective component of TISF is comprised of at least one polypeptide substantially free of additional endogenous materials. The human, feline, canine and bovine TISF of the present invention are substantially homogeneous 50 kDa glycoproteins with isoelectric points of 6.5.
The amino acid composition of TISF is unlike that of any known cytokine or thymic peptide. The amino acid composition of bovine TISF was determined by conventional methods known to those of skill in the art and is as follows.
Asparagine/Aspartate--8.8%; Threonine--3.5%; Serine--14.7%; Glutamine/Glutamate--13.3%; Proline--2.2%; Glycine--25.7%; Alanine--6.1%; Valine--4.3%; Isoleucine--3.4%; Leucine--6.3%; Tyrosine--2.3%; Phenylalanine--2.6%; Histidine --2.2%; Lysine--4.7%
TISF was purified on a larger scale according to the following protocol. Seed cultures of Fe2F, Ca-9, TF4, or HU1 were removed from frozen culture and grown in 25 Cm 2 tissue culture dishes in supplemented DMEM. After 14-21 days incubation at 36° C., cultures were used to inoculate a hollow fiber bioreactor. 5×10 6 -10 8 cells were inoculated into the extracapillary space (ECS) of an artificial capillary bed. One liter of DMEM supplemented with L-glutamine and antibiotics (e.g., penicillin G, 100 U/ml or streptomycin, 100 μg/ml) was circulated in the capillary bed.
After seeding the reactor and allowing for adaptation (3-6 weeks), the concentration of fetal bovine serum was gradually decreased to approximately 0.5% in the media. Cultures were fed every other day by replacement of the circulating capillary bed media. Product was harvested from the media removed from the ECS of the reactor. In one procedure, for example, 500-1000 ml media was exchanged in the capillary bed and 30 ml in the ECS.
When one liter of ECS fluid was collected, it was clarified by centrifugation. The clarified material was passed through a sterile chromatography column which contained a strong cation exchange resin (Sepharose S, Pharmacia) with a high affinity for the product at low salt concentrations. The column was eluted with increasing salt concentrations to 0.5M, whereby all extraneous material was removed from the column. The strongly cationic product was then eluted with sterile 2M buffered saline. The material was then diluted with sterile water to the concentration of normal saline. The final product has a preferable concentration of about 1 μg/ml. The product may be lyophilized, if desired, for long term storage.
Administration of TISF
TISF may be administered to an immunocompromised animal or one with an immature immune system via various means, including parenteral, oral, topical and intraperitoneal administration. A minimally effective dosage of TISF was determined to be about 1 μg/kg of the recipient's body weight. In many of the examples that follow, the dosage range was from about 0.1 μg to about 1 μg TISF per administration; preferably, at least about 5 μg TISF per kilogram of host body weight is administered to the animal with an upper limit of about 500 μg/kg. TISF may efficaciously be administered alone, in combination with another immune potentiator, or incorporated in a pharmaceutically acceptable carrier or excipient.
For treatment of feline immunodeficiency virus infection, cats may advantageously be injected with 1 ml of the above product per week. for treatment of canine or human infections, increased doses are used to adjust for their increased mass and body surface area.
The invention can be better understood by way of the following examples which are representative of the preferred embodiments thereof, but which are not to be construed as limiting the scope of the invention.
EXAMPLE I
In the canine model, TISF has been demonstrated to enhance antibody responses to rabies virus at least 5-fold. In FIG. 3, the effect of canine TISF ("Epithyme™") on anti-rabies virus antibody titers in dogs vaccinated with killed rabies virus vaccine is illustrated. For example, in the control group, which was vaccinated with killed rabies virus vaccine plus alum, anti-rabies virus antibody titers peaked within two weeks at a level well below 250. It is thus striking to observe the results from the experimental group, vaccinated with killed virus and TISF ("Epithyme™"). The animals in the experimental group demonstrated persistent, increased titers which peaked about two weeks postimmunization, at a level exceeding 750. Not only was immune responsiveness enhanced, survival of the animals was enhanced and increased in duration by the administration of TISF.
When one considers the fact that our protocol was preliminary and had not yet been optimized, this result is even more significant. Also, as these tests were performed using semi-purified material, it is expected that use of more highly purified material will show TISF to be even more potent when testing protocols are optimized.
EXAMPLE II
In a second model used to test the efficacy of TISF, canines were immunized with a virulent distemper virus adjuvanted with either alum or canine TISF. Distemper viruses are known to have immunosuppressive effects. The animals were then challenged with a virulent strain of distemper virus to assess protection. A third group--namely, a control, unvaccinated group--was also included in the study.
The survival data are indicated in FIG. 4, which compares the survival rate of the three groups subsequent to canine distemper virus challenge. Clearly, the survival rate of the animals to which vaccine and TISF were administered is about double that of animals receiving vaccine adjuvanted with alum. Since cell-mediated immune (CMI) responses are deemed to be important in the protection against distemper, it is anticipated that measurement of lymphocyte proliferation response will correlate well with survival rates in the vaccine-plus-TISF group.
EXAMPLE III
The beneficial in vivo effects of TISF have more recently been demonstrated in relation to a third viral disease, i.e., influenza. It is generally believed that organisms are more susceptible to influenza ("flu") infection if they are already experiencing some immunosuppressive condition--e.g., stress or chemotherapy--albeit the flu infection itself is also immunosuppressive.
In a mouse model of infection, the primary protection, as in humans, is provided by increased antibody titers to the hemagglutinin antigen (HA). In a primary response to flu, HA titers were enhanced 8-fold. Titers were 1:20 in young mice inoculated with virus alone, and were 1:160 in mice receiving viral inoculations plus TISF. The cell-mediated response to influenza virus is critical for the recovery from the infection. This is important because the CMI is directed to a highly conserved, non-structural gene product expressed on infected cells that is common to all known influenza A strains. Therefore, if one becomes infected with influenza due to the genetic variability of the HA molecule, a more vigorous CMI response could very well shorten the duration of the illness, since "memory" CMI would be cross-reactive to all flu strains.
In order to test this possibility, mice that had been infected with influenza plus or minus bovine TISF several weeks previously were tested for a secondary cytotoxic killer cell response against target cells infected with influenza virus. FIG. 5 illustrates secondary CMI response to influenza. The killing activity as measured by target cell lysis was enhanced at least 9-fold with lymphocytes from the TISF recipients.
EXAMPLE IV
Clinical Protocol
TISF has been demonstrated herein to enhance immune reactivity or responsiveness to several viral diseases. Weekly or twice-weekly administrations of TISF are expected to improve the immune status of felines infected with FIV.
Eleven cats ranging in age from one to three years were obtained from Dr. Janet Yamamoto at the University of California at Davis. The cats were experimentally infected with the Petaluma strain of FIV as controls in a vaccine trial. (See Pedersen, et al., Science 235: 790-93 (1987), which is incorporated herein by reference.)
All cats were determined to be FIV positive by Dr. Yamamoto but manifested no disease symptoms upon arrival at the test facility. The basic testing protocol is as follows:
1. Allow felines to rest and acclimate for about two weeks.
2. Obtain blood samples prior to initiation of treatment for baseline determination of lymphocyte counts and/or T4/T8 ratios.
3. Randomly assign felines to treatment (6 cats) or control (5 cats) groups.
4. Inject treatment group felines subcutaneously with 1.0 ml feline TISF in purified or semipurified form.
5. Obtain blood samples on a weekly basis prior to each injection. Monitor clinical signs and record findings.
6. Obtain bone marrow and/or blood sample for use in FIV detection test in treatment and control animals (e.g., appropriate staining of blood smears).
The six cats treated with TISF showed a statistically significant lessening of the period of lymphopenia encountered early in the course of FIV disease when compared to the five untreated controls (FIG. 6). Clinically, the experimentally treated group recovered much more rapidly from the signs of viral upper respiratory infections that were exhibited by all eleven animals. Finally, examination of blood and bone marrow from the animals confirmed that the group experimentally treated with TISF had improved virologic status and marrow cellularity when compared with controls.
EXAMPLE V
The following Table IV illustrates the results of treating symptomatic FIV positive cats in several private veterinary clinics with 1 ml/week of the product of the present invention comprising TISF in an injectable carrier at a concentration of 3 units/ml. As seen from the data in the table, all eight cats showed symptomatic improvement as well as increased peripheral blood lymphocyte counts after treatment with TISF.
TABLE IV__________________________________________________________________________CLINICAL STUDIESBEFORE Rx AFTER RxPATIENT SYMPTOMS LYMPHS SYMPTOMS LYMPHS__________________________________________________________________________SH severe gingivitis 9% much improved 17% severe stomatitis eating well cryptococcus titer 1:500 crypto titer 1:200JH lethargic 15% no symptoms 39% nasal discharge crypto crypto titer titer neg.RJ mucoid diarrhea 37% increased energy and ND appetite mouth improvedDH diarrhea 19% eating well 25% sneezing normal appearanceBH anorexic 18% appetite improved 28% conjunctivitis improved appearanceAK anorexic 4% strong, doing better 21% lymphadenopathy appearance improved lethargic & depressed eating wellJN weight loss 24% feeling better 25% respiratory infection doing o.k. swollen joints (abs. 4536/mm.sup.3) (abs. 2016/mm.sup.3)MH very ill, weak 0% much improved 9% respiratory infection infection resolved weight loss gained weight__________________________________________________________________________
EXAMPLE VI
TISF produced by bovine thymic epithelial cells was tested for antiviral activity against the Human Immunodeficiency Virus (HIV). Human peripheral blood lymphocytes used for this in vitro test were obtained from healthy HIV-negative donors and were purified using discontinuous gradient centrifugation and Lymphocyte Separation Medium (Organon Teknika). The lymphocytes were stimulated initially with phytohemagglutinin (PHA) and were then maintained in a medium of RPMI-1640 and DMEM. Cells from this culture were concentrated and suspended in an inoculum of a known HIV strain (H112-2) for two hours. The cells were then washed to remove unabsorbed virus and were resuspended in fresh medium. 2×10 5 cells were dispensed into wells of a 24-well plate. Various concentrations of bovine TISF in two-fold dilutions from 1:5 to 1:160 were added to wells containing infected cells and to control wells containing uninfected cells.
Interleukin-2 (IL-2), in concentrations that varied between different plates, was added to the medium to assess the effect of varied lymphocyte stimulation levels. Cell controls (untreated, uninfected) and viral controls (untreated, infected) were included on each plate. Dideoxyinosine (DDI), a known powerful anti-HIV agent, was assayed as a positive control. The plates were cultured for 5 days at 37° C. in a humidified 5% CO 2 atmosphere. On the fifth or sixth day post-infection, a sample of the supernatant medium from each test well was collected and tested for HIV p24 core antigen concentration using an ELISA (Dupont Company, Boston, Mass.). The results of these determinations shown as the percent reduction in p24 antigen concentration compared with untreated viral controls are shown in Table V.
TABLE V__________________________________________________________________________ANTIVIRAL ACTIVITY OF TISF IN THE PRESENCE OF IL-2 1.0 u/ml .32 u/ml 0.1 u/ml Antiviral Antiviral Antiviral Activity Activity ActivityIL-2 p24 Reduction p24 Reduction p24 ReductionDOSAGE (ng/ml) (%) (ng/ml) (%) (ng/ml) (%)__________________________________________________________________________TISF 1:5 432.9 27.8 247.3 33.6 90.13 46.9TISF 1:10 517.3 13.7 292.4 21.5 92.93 45.2TISF 1:20 531.9 11.3 307.2 17.6 98.96 41.7TISF 1:40 579.3 3.4 313.7 15.8 111.6 34.2TISF 1:80 571.2 4.7 287.2 22.9 103.7 38.9TISF 1:160 602.2 -0.4 309.6 16.9 115.5 31.9VIRAL CONTROL 599.6 -- 372.6 -- 169.6 --DDI 100 μM 0.312 99.96 ND+ -- ND --DDI 31.6 μM 4.431 99.4 ND -- ND --DDI 10 μM 158.8 79.0 ND -- ND --DDI 3.16 μM 406.4 46.2 ND -- ND --DDI 1 μM 529.1 30.0 ND -- ND --DDI .316 μM 551.7 27.0 ND -- ND --VIRAL CONTROL 755.6 -- ND -- ND --__________________________________________________________________________ *HIV p24 core antigen measured by ELISA +ND = not determined
The effect of TISF on cell growth was assessed to verify that the viral inhibition it produced was not merely a reflection of cytotoxicity against the infected cells themselves, rather than an antiviral effect. A MTT-formazan dye assay was used to identify and quantify viable cells from uninfected wells at each dose dilution of TISF. This assay relies on the reduction by living cells of an MTT tetrazolium salt to form a blue formazan product. As shown in Table VI, while some cytotoxicity was seen at high TISF doses in cells under high IL-2 stimulation, at the lower concentrations and lower IL-2 levels more achievable in therapeutic situations, significant viral inhibition was noted even in the presence of increased cell growth.
TABLE VI__________________________________________________________________________EFFECT OF TISF ON CELL GROWTH IN THE PRESENCE OF IL-2 1.0 u/ml .32 u/ml 0.1 u/ml Cell Cell Cell Viability Viability ViabilityIL-2 MTT (%) Cell MTT (%) Cell MTT (%) CellDOSAGE Abs Growth Abs Growth Abs Growth__________________________________________________________________________TISF 1:5 0.994 92.6 0.761 85.1 0.371 81.7TISF 1:10 1.029 95.8 0.818 91.5 0.433 95.4TISF 1:20 1.059 98.6 0.828 92.6 0.457 102.9TISF 1:40 1.085 101.0 0.866 96.9 0.508 111.9TISF 1:80 1.07 99.6 0.872 97.5 0.541 119.2TISF 1:160 1.129 105.1 0.889 99.4 0.544 119.8CELL CONTROL 1.074 100.0 0.894 100.0 0.454 100.0DDI 100 μM 0.885 74.9 ND+ -- ND --DDI 31.6 μM 1.096 92.7 ND -- ND --DDI 10 μM 1.067 90.3 ND -- ND --DDI 3.16 μM 1.077 91.1 ND -- ND --DDI 1 μM 1.1 93.3 ND -- ND --DDI .316 μM 1.169 98.9 ND -- ND --CELL CONTROL 1.182 100.0 ND -- ND --__________________________________________________________________________ *MTT formazan absorption by living cells +ND = not determined
This study demonstrated a striking reduction in the viral load of HIV-infected human lymphocytes caused by TISF that was not due merely to a cytotoxic effect. While the antiviral effect of TISF was less potent than that of DDI, TISF maintained its viral inhibition even under conditions where it also stimulated an increase in lymphocyte numbers. The foregoing detailed description of the invention and the preferred embodiments, especially with respect to product compositions and processes, is to be considered illustrative of specific embodiments only. It is to be understood, however, that additional embodiments may be perceived by those skilled in the art. The embodiments described herein, together with those additional embodiments, are considered to be well within the scope of the present invention. | The present invention relates generally to the fields of immunology and molecular biology, and particularly to a thymus-derived factor which stimulates, enhances or regulates cell-mediated immune responsiveness. In one embodiment, the factor is a substantially homogeneous immune potentiator which stimulates mature T lymphocytes and thus enhances the response of animals, especially mammalian organisms, to infectious agents and to malignancies. | 2 |
RELATED APPLICATION
[0001] This application hereby claims priority under 35 U.S.C.§119 to U.S. Provisional Application 61/164,660 entitled “Thorp Mode Encryption,” by Benjamin J. Morris, Philip Rogaway, Terence Spies, and Till Stegers, filed Mar. 30, 2009 (Atty. Docket No.: UC095511PSP).
BACKGROUND
[0002] 1. Field
[0003] The present embodiments relate to cryptographic techniques for constructing a blockcipher-based encryption scheme. More specifically, the present embodiments relate to techniques for constructing fast and provably secure schemes for deterministically enciphering data from a small domain, like credit card numbers, using a conventional block cipher.
[0004] 2. Related Art
[0005] Imagine wanting to encrypt a nine-decimal-digit plaintext, such as a U.S. Social Security number, into a ciphertext that is also a nine-decimal-digit number. This operation is useful for storing the ciphertext in the same record structure as the plaintext. Modern cryptographic techniques typically assume the plaintext input to a block cipher has a block size of 128 bits and that the block cipher outputs a ciphertext of 128 bits. Unfortunately, nine-decimal-digit plaintext input and nine-decimal-digit ciphertext output are incompatible with a block size of 128 bits.
[0006] One could imagine attempting to construct the desired scheme directly, by modifying a known primitive, but such constructions have many shortcomings. For example, one could modify the definition of the Advanced Encryption Standard (AES) so that it would take in a nine-decimal-digit plaintext and output a ciphertext that is also a nine-decimal-digit number. But both the specification and implementations of AES have been carefully crafted, and the specification has been in the public domain for a considerable time, so a modified version of AES would need careful study by many cryptographers to determine whether the level of security believed to be provided by AES was compromised. As such, it is neither feasible nor desirable to employ such an approach.
[0007] In an alternative approach, rather than modifying AES, one could embed the nine-decimal-digit plaintext one wants to encrypt into a 128-bit string, and then invoke AES. Because AES returns a 128-bit string, the output would have to be mapped back into a nine-decimal-digit number. But it is impossible to encode a 128-bit string into nine decimal digits, since 2 128 >10 9 .
[0008] Is it really a problem if one cannot encrypt nine-decimal-digit numbers into nine-decimal-digit numbers? Consider a database of U.S. Social Security numbers. Suppose one wished to silently replace all of the Social Security numbers with encrypted Social Security numbers. Using AES to produce an output of 128 bits and using this in place of the nine-decimal-digit numbers would break existing applications that access and manipulate U.S. Social Security numbers, because such applications, expecting nine-decimal-digit strings, are now faced with 128-bit binary strings instead. Further, the database schema for each table containing U.S. Social Security numbers would need to be changed to support a different data type, and dependent applications would need to be modified accordingly. Conventional block ciphers like AES are, therefore, not directly usable to encrypt on small domains of practical interest, because these techniques send 128-bit inputs to 128-bit outputs.
[0009] Hence, what is needed is a cryptographic technique to encipher elements from a small domain into elements of the same small domain.
SUMMARY
[0010] The present embodiments provide a practical system for enciphering input data drawn from a small domain into output data that is also drawn from the same domain. The system can be based on a conventional block cipher. Further, the system's process of enciphering can be sped up significantly to reduce the number of invocations of a conventional block cipher that are needed. Finally, the system is practical and can enjoy provable security guarantees.
[0011] In some embodiments, the small domain that can be enciphered is the set of credit card numbers or the set of U.S. Social Security numbers. In general, the domain can be the set of all strings of some fixed length n, where each string consists of base-k characters for some k≧2.
[0012] In some embodiments, the system's process of enciphering elements from a small domain can be likened to shuffling cards. Each step in the enciphering process is analogous to shuffling a deck of cards. Each card represents a message with the domain of the cipher.
[0013] In some embodiments, the system's process of enciphering can be sped up by five times compared to a more naïve embodiment.
[0014] In some embodiments, the system's process of enciphering can be sped up by two times compared to a more naïve embodiment.
[0015] In some embodiments, a conventional block cipher like AES (the Advanced Encryption Standard) is used to implement a pseudorandom function that generates pseudorandom bits and is used internally within the embodiment.
[0016] In some embodiments, the obliviousness property of a card shuffle—the property of a shuffle that you can trace the trajectory of a card without attending to the trajectories of other cards—is the basis of the encryption scheme that is subject to the speed-up technique.
BRIEF DESCRIPTION OF THE FIGURES
[0017] FIG. 1 shows two examples of domains for small-space encryption in accordance with an embodiment.
[0018] FIG. 2 shows the major components of an implementation of a cipher E in accordance with an embodiment.
[0019] FIG. 3 shows a detailed example of how to encrypt a value drawn from the domain of playing cards numbered 0, . . . , 7 to another value in the same domain in accordance with an embodiment.
[0020] FIGS. 4A-4B show a detailed example illustrating the speed-up optimization to perform five rounds of enciphering using a single call to the underlying pseudorandom function in accordance with an embodiment.
[0021] FIG. 5 shows a flowchart illustrating the process of performing five rounds of enciphering using a single call to the underlying pseudorandom function as a way of speeding up the process of enciphering for n-bit input strings in accordance with an embodiment.
[0022] FIG. 6 illustrates the process of encrypting a U.S. Social Security number to another number in the same domain in accordance with an embodiment.
[0023] FIG. 7 shows a flowchart illustrating the process of performing two rounds of enciphering using a single call to the underlying pseudorandom function as a way-of speeding up the process of enciphering for n-decimal-digit input strings in accordance with an embodiment.
[0024] FIG. 8 illustrates the general process of encrypting a message in the format of an n-character input string where the character is base-k through p phases of enciphering in accordance with an embodiment.
[0025] FIG. 9 illustrates the process of invoking a choice function on the input register and the speed-up register to return a pseudorandom character string in accordance with an embodiment.
[0026] Table 1 illustrates the Thorp shuffle technique with the obliviousness property in which only card seven is shuffled through four rounds in accordance with an embodiment.
[0027] Table 2 illustrates how the enciphering system concatenates bits from the input string to index into a speed-up register to obtain a random bit in accordance with an embodiment.
[0028] Table 3 illustrates some example parameter sets in accordance with an embodiment.
[0029] In the figures, like reference numerals refer to the same figure elements. Moreover, multiple instances of the same type of part may be designated by a common prefix separated from an instance number by a dash.
DETAILED DESCRIPTION
[0030] The following description is presented to enable any person skilled in the art to make and use the present embodiments, and is provided in the context of a particular application and its requirements. Various modifications to the disclosed embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments and applications without departing from the spirit and scope of the present embodiments. Thus, the present embodiments are not limited to the embodiments shown, but are to be accorded the widest scope consistent with the principles and features disclosed herein.
[0031] The data structures and code described in this detailed description are typically stored on a computer-readable storage medium, which may be any device or medium that can store code and/or data for use by a computer system. The computer-readable storage medium includes, but is not limited to, volatile memory, non-volatile memory, magnetic and optical storage devices such as disk drives, magnetic tape, CDs (compact discs), DVDs (digital versatile discs or digital video discs), or other media capable of storing computer-readable media now known or later developed.
[0032] The methods and processes described in the detailed description section can be embodied as code and/or data, which can be stored in a computer readable storage medium as described above. When a computer system reads and executes the code and/or data stored on the computer-readable storage medium, the computer system performs the methods and processes embodied as data structures and code and stored within the computer-readable storage medium. Furthermore, the methods and processes described below can be included in hardware modules. For example, the hardware modules can include, but are not limited to, application-specific integrated circuit (ASIC) chips, field-programmable gate arrays (FPGAs), and other programmable-logic devices now known or later developed. When the hardware modules are activated, the hardware modules perform the methods and processes included within the hardware modules.
[0033] Embodiments provide a method and system for deterministically enciphering plaintext in a small domain such as U.S. Social Security numbers or credit card numbers into a ciphertext in the same domain. More generally, embodiments provide a method and system for deterministically enciphering plaintext in a small domain consisting of all strings of identical length over some finite alphabet.
[0034] FIG. 1 shows two examples of systems that operate in small domains in accordance with some embodiments. The first system enciphers a 16-decimal-digit credit card number 102 , the plaintext, into a ciphertext 104 that is also a 16-decimal-digit number. The second system is an example of a database of Social Security numbers 106 stored in a table of the database. In this example, the system enciphers each nine-decimal-digit U.S. Social Security number into a ciphertext that is also a nine-decimal-digit number, which looks just like another Social Security number. The ciphertext result is stored in place of the original Social Security number, updating the corresponding field in the database table. It is also possible to decipher each such Social Security number ciphertext to recover the original upon retrieval from the database. Another example of a small domain (not shown) is pieces of credit card numbers in which, say, the last five digits are shown in the clear and the first 11 digits are encrypted in accordance with an embodiment. These examples are not meant to limit the scope of the present invention but serve to illustrate their possible domains of use.
[0035] The examples given are a special case of “format-preserving encryption” (FPE). In an FPE scheme, encryption is deterministic and the format of the ciphertext is identical to that of the plaintext. The advantage of FPE is that it simplifies adding encryption to systems with legacy data like the database because field types for the legacy data need not be changed when the data is enciphered.
[0036] In the systems illustrated in FIG. 1 we show a box labeled E KT , the enciphering system, which takes an input string such as a credit card number or a U.S. Social Security number and returns its respective enciphered output. More specifically, we define a cipher, a map : × × → where , and are finite non-empty sets and where is a permutation on for every K ε and T ε The set is the key space, the set the tweak space, and the set is the domain. The shared key K controls the encryption. Both the key space and the domain are sets of strings drawn from an arbitrary alphabet (a finite, non-empty set of characters). The elements of set are called plaintexts, or messages, and the number of them is denoted by | |=N.
[0037] The tweak space is a set of arbitrary byte strings. The set should be large enough to accommodate all non-secret information that may be associated with a plaintext. Users are strongly encouraged to employ tweaks whenever possible, as their judicious use can significantly increase security. The intuition behind using a tweak in an FPE scheme is that we want knowledge of where a plaintext maps to under a tweak T does no good in trying to figure out where the same or even all plaintexts maps to under a different tweak T′.
[0038] The cipher should have following properties: (1) given a key and a tweak, it is bijective, that is, it is a one-to-one and onto function; (2) it is deterministic—it does not depend on any internal randomness or “coins;” (3) it is practical—meaning that it is simple and fast to compute; and (4) it is provably secure—meaning that a proof is known that provides a significant assurance that it is a good pseudorandom permutation. In saying that is a good pseudorandom permutation we mean that a black box for computing with respect to a random key K ε looks to an adversary with reasonable computational means like a family of independent random permutations on indexed by tweaks in the tweak space.
[0039] In one or more embodiments, if the domain is the space of U.S. Social Security numbers, then ={0, 1, . . . , N-1}, and N=10 9 . FIG. 1 shows encrypting a Social Security number in terms of the cipher via , K, T, 348-88-2346)=234-60-6477 (where hyphens are retained to show that the ciphertext is a U.S. Social Security number). In one or more embodiments, if the domain is the space of 16-digit credit card numbers, then ={0, 1, . . . , N-1}, where N=10 16 . Further, FIG. 1 shows encrypting a credit card number in terms of the cipher via E(K, T, 4000 1234 5678 9123)=5887 3229 0447 4263.
[0040] FIG. 2 shows the major components of an implementation of a cipher in one embodiment of the present invention. The components implement a tweaked pseudorandom permutation on for every key in and every tweak in The cipher mechanism receives three arguments as inputs, namely a “Key” 202 , a “Plaintext” 204 , such as a credit card number or a U.S. Social Security number, and a “Tweak” 206 . The “Plaintext” 204 is stored in an n-character register 208 . “Key” 202 is an element of the set of keys , which may be defined as a set of 128-bit strings, where is the set of keys of the pseudorandom function. “Tweak” 206 is an element of the set of tweaks which contains strings of bytes drawn from the set BYTE ≦j where J=2 64 1 and BYTE denotes {0,1} 8 , the set of 8-bit bytes. Note that characters are the most general format because they include bits, decimal digits, and hexadecimal digits, to name a few. The pseudorandom function 210 is the key to making the cipher practical and realizable; the function takes a round number, the key “Key” 202 , and the tweak “Tweak” 206 and outputs a fixed-length pseudorandom base-k character string. In one embodiment, this pseudorandom function 210 can be constructed from the CBC-MAC of AES (Advanced Encryption Standard). In yet another variation, the pseudorandom function 210 can be implemented using CMAC. In another variation, the key K itself can be a 128-bit quantity, a 192-bit or even a 256-bit quantity, depending on the level of security desired.
[0041] The “combining function” 212 takes a pair of equal length strings and returns a string of the same length. In one embodiment, when messages are bit strings, the combining function may be modulo-2 addition, also known as exclusive-or. In another embodiment, when messages are decimal strings, the combining function is modulo-10 addition. In the general embodiment, the combining function 212 may be modulo-k addition for base-k characters. The output of the cipher 200 as a result of performing the computation 212 is “Ciphertext” 216 , which is in the same domain as the input “Plaintext” 204 .
[0042] What is the reason for including a tweak in the cipher ? Suppose we are enciphering the six middle digits of a 16-digit credit card number; the remaining ten digits are to be left in the clear. If we use a deterministic and tweakless scheme, there is a danger that an adversary might be able to create, by noncryptographic means, an unnecessarily useful dictionary of plaintext/ciphertext pairs (X, Y), where X is a 6-digit number and Y is its encryption. Each plaintext/ciphertext pair (X, Y) that the adversary somehow obtains (acquired, for example, by a phishing attack) would let the adversary decrypt every credit card number that happens to have those same six middle digits. Note that in a database of 100 million entries we would expect about 100 credit card numbers to share any given six middle digits. Learning k credit card numbers and possessing an encrypted database ought not give you 100k more credit card numbers for free.
[0043] The problem is not a cryptographic failure, but a failure to use a good tool well. The middle-six digits ought to have been tweaked by the remaining ten. If this had been done then learning the credit card number 1234-123456-9876 encrypts to 1234-770611-9876, say, would not let one decrypt 1111-770611-9999, as the mapping of 123456 to 770611 is specific to the surrounding digits 1234/9876.
[0044] In general, it is desirable to use all information that is available and statically associated to a plaintext as a tweak for that plaintext. In the most felicitous setting of all, the non-secret tweak associated to a plaintext is associated only to that plaintext. Extensive tweaking means that fewer plaintexts are enciphered under any given tweak. This corresponds, in the pseudorandom function model we have adopted, to fewer queries to the target instance. The relevant metric is the maximum number of plaintexts enciphered with the same tweak, which is likely to be significantly less than the total number of plaintexts enciphered.
[0045] To implement the cipher , we need a representation of a message (the plaintext) and a procedure to “mix” the key K with the message. To be deterministic, practical and provably secure, the cipher can be based on the idea of shuffling a deck of cards. Shuffling is equivalent to generating a random permutation of the cards. There are two basic algorithms for doing this. The first is simply to assign a random number to each card, and then to sort the cards in order of their random numbers. This will generate a random permutation, unless two of the random numbers generated are the same. This can be eliminated either by retrying these cases, or reduced to an arbitrarily low probability by choosing a sufficiently wide range of random number choices. The second, generally known as the Knuth shuffle or Fisher-Yates shuffle, is a linear-time algorithm, which involves moving through the pack from top to bottom, swapping each card in turn with another card from a random position in the part of the pack that has not yet been passed through (including itself). Providing that the random numbers are unbiased, this will always generate a random permutation.
[0046] A variation on these algorithms is the Thorp shuffle, where the deck is cut into two equal-sized piles. Intuitively, cipher encrypts by “shuffling” a set of messages using Thorp's method, where these messages can be thought of as cards in a large deck. Consider such a deck of N cards where N is even. We wish to shuffle all the cards in the deck. First, cut the deck into two equal piles. Second, according to the outcome of a fair coin flip, drop the bottom card from either the left or right pile, and then drop the card from the bottom of the other pile. Continue in this way, flipping a total of N/2 independent coins, using each to decide if cards are dropped left-then-right or right-then-left, until there are no more cards. This is one round of the shuffle in which all cards from the two decks have been shuffled back into a single deck. Cut the deck again into two equal-sized piles and repeat the shuffle procedure for as many rounds as needed to mix the cards sufficiently.
[0047] To see the Thorp shuffle in action, imagine that the single deck of cards has been cut into two decks: one deck is labeled “deck 1” (left pile) and the second deck is labeled “deck 2” (right pile). In this unusual deck there are only eight cards, each labeled with a number 0, 1, 2, 3, 4, 5, 6, and 7. Consider the Thorp shuffle with 4 rounds on this deck of cards. Cards 0-3 are in deck 1, and cards 4 -7 are in deck 2.
[0048] Consider the pair of cards 0 and 4 at the bottom of each deck. To shuffle the deck, how do we decide in which order to drop the bottom cards? Do we drop card 0 and then card 4? Or, do we drop card 4 first and then card 0 48 Flipping a fair coin makes this determination: for example, “heads” (coin flip=0) means drop left-then-right and “tails” (coin flip=1) means drop right-then-left. For card pair (0, 4) we flip a coin; it comes up “heads,” so we drop card 0, and then drop card 4. The new deck being formed has card 0 at the bottom with card 4 on top of it. For each pair of remaining cards (1,5), (2,6) and (3,7), we flip a coin. Let us assume that “tails” is associated with (1,5), “tails” with (2,6) and “heads” with (3,7).
[0049] After performing the drop procedure for each pair of cards associated with each coin flip, the new deck is shown viewed from left to right instead of bottom to top: 0 4 5 1 6 2 3 7. After one round, the entire deck of eight cards has been shuffled using four independent coin flips. If we define a minimum, called a pass, as ┌ log 2 N┐ then the total number of coin flips used in a pass is ┌ log 2 N┐·N/2. Here ┌·┐ computes the ceiling function such that ┌x┐ is the smallest integer not less than x. The Thorp shuffle can mix the deck well after a small number of passes.
[0050] Whenever N cards are shuffled in this fashion, all the cards are being shuffled at the same time. Yet, it is possible to trace the route of any given card in the deck through each successive round of the shuffle without attending to the remaining cards in the deck. The Thorp shuffle is said to be oblivious to other cards in the deck in that one can focus on the route a single card takes as it is shuffled in multiple rounds; one need not be concerned with the route of other cards. An embodiment of the present invention leverages this obliviousness property of the Thorp shuffle: a sufficient number of rounds that mix the cards quickly enough makes encrypting over small domains practical and feasible.
[0051] To explain the obliviousness property of the Thorp shuffle, consider the same deck of eight cards in its original configuration: 0 1 2 3 4 5 6 7. Employing the obliviousness property, we can ignore seven of the cards and consider just shuffling card 7 in the deck. Alternatively, think of “encrypting” 7 by applying the Thorp shuffle and only looking at the route of 7 during the course of the shuffle. Table 1 shows the Thorp shuffle oblivious to all but card 7. Given the coin flips tails (1), heads (0), tails (1), and heads (0) for the pairs in which card 7 is involved, the four rounds of shuffling show that card 7 ends at position 4 (numbering the positions in the horizontal deck from 0 to 7). Thus, the result of encrypting 7 is 4 or (K, T, 7)=4 for some K and T. The cards we do not care about are labeled with an asterisk “*” to focus our attention on 7. Note that 4 is drawn from the same domain as 7, namely ={0, . . . , N-1}, where N=8.
[0000]
TABLE 1
Thorp Shuffle (Compute E(K, T, 7) = 4)
Card position
Round number
0 1 2 3 4 5 6 7
Coin flips
* * * * * * * 7
1
* * * * * * 7 *
Tails (1) right-then-left
2
* * * * * 7 * *
Heads (0) left-then-right
3
* * 7 * * * * *
Tails (1) right-then-left
4
* * * * 7 * * *
Heads (0) left-then-right
[0052] The Thorp shuffle, due to its obliviousness, provides a practical method to encrypt messages over small domains. To implement the shuffle, and therefore the cipher , we need (1) a representation of the messages in space ; and (2) a function that realizes uniform random coin flips.
[0053] First, we represent all messages in space , or the cards in the deck, by strings of the same length n over some fixed alphabet. In one embodiment, where N=2″, messages are represented as a n-bit strings, so that for instance card 7 in the shuffle would be represented by the binary string 111. In general, if N=k n , then each message in ={0, . . . , k n -1} a string of n base-k digits.
[0054] Second, to implement the behavior of fair coin flips, we make use of a pseudorandom function family. The function (family) is said to be pseudorandom because it possesses the property that the input-output behavior of an instance of the family of such functions determined by a random key is computationally indistinguishable from a random function with the same signature. In an embodiment over an alphabet E the signature of this pseudorandom function is × × *→{0,1}, that is, given a key, a tweak, a round number, and a message, the function returns a pseudorandom bit of 0 or 1.
[0055] The key space is identical to the key space of the cipher . For a key K, we use the notation κ(·) rather than (K, ·) to indicate a pseudorandom function keyed with key K. The total number of random bits needed to shuffle a single card for R rounds is R bits, not (N/2)·R bits which would be needed to shuffle the entire deck. (The property of being able to follow the trajectory of a single card without attending to all the other cards is called obliviousness.) Table 1 shows R=4 rounds of the shuffle, and that four random bits are needed to implement the four coin flips. In a naive embodiment, the invocation of the pseudorandom function on each round returns a pseudorandom bit. The reason the round number is included as an argument to the pseudorandom function is to ensure that the pseudorandom bits are indeed generated independently for different rounds. The reason the tweak is included is ensure that the encryption processes for different tweaks, even for the same plaintext, are independent.
[0056] In one or more embodiments, the pseudorandom function could be implemented using the CBC-MAC of AES, the Advanced Encryption Standard. The CBC-MAC is a well-known method for using the Cipher Block Chaining mode of operation to turn a block cipher into a Message Authentication Code (MAC). When implemented using the CBC-MAC, the function must be constructed in such a way that the set of inputs on which the CBC-MAC is invoked is prefix-free, that is, for any distinct inputs x, y, x is not a prefix of y. This is because the CBC-MAC is known to be a good pseudorandom function when invoked on a set of prefix-free inputs, assuming that the underlying block cipher is a good pseudorandom random permutation. In addition to the CBC-MAC, the pseudorandom function could also be implemented using the CMAC mode of operation.
[0057] The pseudorandom function typically needs to make only a single AES call per pseudorandom function invocation, provided the tweak has been preprocessed. Note that an AES call returns a 128-bit string. The pseudorandom function will pick one of these 128 bits and return just one bit; in one embodiment function returns bit 127. This is reasonable and practical because all 128 bits are guaranteed to be pseudorandom and, therefore, any bit chosen is pseudorandom.
[0058] FIG. 3 illustrates a practical realization of the Thorp shuffle on a bit string of length n=3 in accordance with some embodiments. In this example illustrating an embodiment where N=8 =2 3 and R=4, we trace the encryption of 7 (in binary, 111). We show that in this example the encryption yields KT (7)=4 ( 300 ), just as we showed using cards. Note that the notation where “KT” is a subscript of cipher indicates that the computation relies on the key K and the tweak T, which remain unchanged during the computation performed by Suppose that bit string 111 is stored in an n-bit register called reg 302 . The string is divided into two parts: reg[0] (the left side) and reg[1 . . . 2] (the right side).
[0059] In round 1 ( 312 ), the system invokes the pseudorandom function KT 304 with the round number 1 and the value of reg[1 . . . 2]=11 as the arguments and outputs a pseudorandom bit KT (r=1, x=11)=1. The system computes the exclusive-or (which is one embodiment of the combining function 212 shown in FIG. 2 ) of this pseudorandom bit with the value of reg[0] and outputs the 1-bit value 1 xor 1=0. Then the system concatenates reg[1 . . . 2] (right side) with the value 0 output by the combining function 212 , resulting in the string 11 ∥0. This concatenated result is stored in reg. After one round, the new state is 110, or 6 in decimal, which can be seen in the new state of the n-bit register 310 . Following the same procedure outlined above for each subsequent round, at the end of round 2 ( 314 ), the original plaintext 7 has been encrypted to the value 5 ( 316 ), after round 3 ( 318 ) to 2 ( 320 ), and, finally, after round 4 ( 322 ) to 4 ( 324 ), the value we expected and the same value returned in the Thorp shuffle of card 7.
[0060] For every round of the shuffle in this particular embodiment, the pseudorandom function invokes the CBC-MAC of AES exactly once. This is because the CBC-MAC of the tweak can be cached, utilizing the fact that CBC-MAC K 0, X 1 ∥X 2 )=CBC-MAC K (CBC-MAC K (0, X 1 ), X 2 ), where CBC-MAC K (V, X) denotes the CBC-MAC of a sequence of blocks X starting with initialization vector V. With this preprocessing in mind, we refer to such a CBC-MAC invocation also as an AES call or AES invocation. Each CBC-MAC invocation returns an independent pseudorandom 128-bit string, ensuring that different rounds behave independently—but only 1 pseudorandom bit is returned by the pseudorandom function KT . Because the computation required for each AES call is potentially expensive, it seems especially wasteful that the above procedure only uses 1 bit for each round when 128 bits are available. In another embodiment of the present invention, these 128 bits from one AES call can be shared by multiple rounds. In particular, if n≧5 for N=2 n , then for each group of five rounds—called a phase—only one AES call is required. Each round uses a different non-overlapping 16-element subset of these same 128 bits to provide separation between different rounds. In particular, this embodiment of the optimization uses 5·2 4 =80 bits of the 128 bits returned from the AES call. This is where the speed-up optimization comes into play—we avoid the expense of calling AES in each round and amortize its cost over five rounds, at the low price of some additional arithmetic and a small number of register lookups.
[0061] FIGS. 4A-4B show this speed-up optimization to encipher a message drawn from the set where the total number of messages in is N=2″ for some n≧5 in accordance with some embodiments. The message to encipher is an n-bit string, stored in an n-bit register MainReg 404 . In one round of the Thorp shuffle presented earlier only the bit in position [0] of MainReg was “active” in the sense that we computed the exclusive-or of that bit value with the output of the pseudorandom function That same bit is still active under this speed-up optimization. What is different is that four other bits of the n-bit MainReg 404 are used to index into a speed-up register SpeedUpReg 412 (which we shall explain shortly) to yield a pseudorandom bit; this bit, as before, is exclusive-or-ed with the active bit. To populate this SpeedUpReg 412 , one AES call ( 410 ) is made at the beginning of the 5-round. This AES call in one phase returns a random 128-bit string, which is then stored in SpeedUpReg 412 . The five rounds making up a phase share the SpeedUpReg 412 to obtain their subsets of bits. The arguments to said AES call are the round number and the bits [5 . . . n] of the n-bit MainReg 404 . Call this bit string Z 408 . The optimization exploits the fact that the substring Z of MainReg is common to the n-bit strings in MainReg 404 in all five rounds of the phase. The call AES K (P(i, Z)) is keyed with key K and takes as an argument, in one embodiment, a prefix-free encoding P(i, Z) of the phase number i and the string Z.
[0062] The reason the speed-up optimization for enciphering n-bit strings performs five rounds and not six rounds is that each round examines a different 16-bit subset of the 128-bits in SpeedUpReg. Since 48 bits remain of the 128-bits considered in the SpeedUpReg, could we not also perform a sixth round and extract 16 of the 48 remaining bits to index into? The answer is no, unfortunately: Six rounds of enciphering per phase for n-bit strings to achieve a six-fold speed-up require that the pseudorandom function output at least 6·2 6-1 bits (6·2 5 =192), which is more than the 128 bits output by our pseudorandom function.
[0063] FIG. 4B shows the state changes of the n-bit register MainReg 404 for each round of a group of five rounds where index j ε (0, 1, 2, 3, 4). We label the bits in MainReg[0], MainReg[1], MainReg[2], MainReg[3], and MainReg[4] at the beginning of round j=0 as b 0 , b 1 , b 2 , b 3 , and b 4 respectively.
[0064] For example, consider the round j=0 ( 402 ) of phase 5i. In MainReg 404 , bit b 0 is the active bit. Bits b 1 , b 2 , b 3 , and b 4 are concatenated to form a new bit string B 406 (shown to the right of the n-bit register as b 1 b 2 b 3 b 4 ). This bit string B 406 is used to index into SpeedUpReg[B+16·j]=SpeedUpReg[B] 414 to obtain one pseudorandom bit. Suppose this bit string is B=1010. When j=0, then SpeedUpReg[1010] indexes into position 10 decimal of the speed-up register. Suppose that the pseudorandom bit SpeedUpReg[1010] is 1. Note that B has four bits, so the index B+16·j always points to a position in the (j+1)-th 16-bit block of SpeedUpReg, ensuring that indices do not repeat across rounds.
[0065] Suppose that the pseudorandom bit SpeedUpReg[1010 2 ] is 1. Next, the system applies the combining function—in this embodiment, the exclusive-or operator—to the value (say) 1 in b 0 =MainReg[0] and the pseudorandom bit SpeedUpReg[1010]=1 to produce a 1-bit output, the value d 0 =0 (1 xor 1).
[0066] Next, the system concatenates the value in bit positions MainReg[1 . . . n—1] with the 1-bit output of the combining function, and stores the result in the register MainReg.
[0067] The new state of the register MainReg consists of bits b 1 , b 2 , b 3 , and b 4 (so that b i occupies bit position [0]), followed by Z, and followed by d 0 . In FIG. 4B , this state is shown in the next round.
[0068] To continue the example, consider the next round. Now j=1. The n-bit register MainReg 404 has the following state: b 1 b 2 b 3 b 4 Z d 0 . Bit b 1 is the active bit. Bits b 2 , b 3 , b 4 , and d 0 are concatenated to form a new bit-string B 418 (shown to the right of the n-bit register). Notice that bit d 0 is a result of the previous round and is appended to b 2 b 3 b 4 to form B=b 2 b 3 b 4 d 0 =0100. This bit string B 418 is used to compute the index B+16·j=4 +16=20 into the SpeedUpReg 420 to obtain the pseudorandom bit SpeedUpReg[20].
[0069] Next, the system applies the combining function to b 1 =MainReg[0] and the pseudorandom bit looked up from SpeedUpReg 412 to produce a 1-bit output d 1 .
[0070] Next, the system concatenates the value in bit positions MainReg[1 . . . n—1] with d 1 and stores the result in the register MainReg.
[0071] This procedure is continued for the next three rounds numbered j=2, j=3, and j=4. The very last state shown in the figure ( 422 ) is the final result of applying all five rounds in this phase to the n-bit register MainReg 404 : Z=d 0 d 1 d 2 d 3 d 4 . If there are more phases remaining in the shuffle, then the phase number is incremented by 1 and the next group of five rounds is computed. Note that there may be fewer than five rounds in the very last phase of the encryption process.
[0072] FIG. 5 shows a flowchart illustrating the speed-up optimization of the Thorp shuffle in accordance with some embodiments. Note that the specific arrangement of steps shown in the figure should not be construed as limiting the scope of the embodiments. The enciphering system begins by invoking the pseudorandom function K (step 502 ), passing in the phase number i, tweak T, and the substring Z=MainReg[5 . . . n-1]. The underlying implementation of this function invokes AES K (P(i, Z)), where P(i, Z) is a prefix-free encoding of the phase number and Z. The AES call outputs a 128-bit string. The system stores this string in the SpeedUpReg.
[0073] Next, the system starts an iteration (step 504 ) where each iteration is called a round and the round number j successively takes on the values 0, 1, 2, 3, 4.
[0074] Next, the system sets B to be the concatenation of bit strings MainReg[1 . . . (4-j)] and MainReg[(n-j) . . . (n-1)] (step 506 ). At first blush, it is not obvious what substrings are being concatenated, yet these correspond merely to the bit positions in MainReg that do not fall into Z. To see this, consider the following example, which borrows from FIG. 4 . Column 1 of Table 2 is j, the round number. Column 2 lists the index range 1 . . . (4-j) for the respective values of j, which extracts the first substring. The reason for this choice of indices is clear: in FIG. 4 you can see that part of each round involves rotating the n-bit register by 1 bit and storing the result of the exclusive-or computation in position [n-1], so in each round Z is preceded by one bit b 1 less. Column 3 shows the bit strings extracted as reg[(n-j) . . . (n-1)]. From one round to the next, this bit string grows by 1 bit. Thus, at index j=0, [1 . . . 4] yields bit string b 1 b 2 b 3 b 4 , and [n . . . (n-1)] selects the empty string. At index j=1, [1 . . . 3] yields bit string b 2 b 3 b 4 and [(n-1) . . . [n-1] yields d 0 . At index j=2, [1 . . . 2] yields bit string b 3 b 4 and [(n-2) . . . (n-1)] yields d 0 d 1 . At index j=4, [1 . . . (4-j)] selects the empty string while [n . . . (n-1)] is d 0 d 1 d 2 d 3 .
[0000]
TABLE 2
Bit concatenation for speed-up optimization
j
1 . . . (4 − j)
(n − j) . . . (n − 1)
B
0
1 . . . 4
n . . . (n − 1)
b 1 b 2 b 3 b 4
1
1 . . . 3
(n − 1) . . . (n − 1)
b 2 b 3 b 4 d 0
2
1 . . . 2
(n − 2) . . . (n − 1)
b 3 b 4 d 0 d 1
3
1 . . . 1
(n − 3) . . . (n − 1)
b 4 d 0 d 1 d 2
4
1 . . . 0
(n − 4) . . . (n − 1)
d 0 d 1 d 2 d 3
[0075] Next, the system consults the SpeedUpReg register (step 508 ) to look up the pseudorandom bit at index [B+16·j]. Note that B has four bits and thus corresponds to an index in {0, . . . , 15}. To ensure that each distinct rounds select among disjoint 16-bit substrings of SpeedUpReg, we add an offset of 16·j to the integer value of B. Thus, round j=0 indexes into the range [0 . . . 15], round j=1 indexes into [16 . . . 31], and so on, until round j=4, which indexes into the range [64 . . . 79]. In other embodiments, the SpeedUpReg need only contain 80 bits from the output of the pseudorandom function, since only indices from 0 to 79 can occur. The system may store more than 80 bits (such as all 128) for efficiency or other reasons without affecting functionality.
[0076] Next, the system invokes the combining function that computes the exclusive-or (step 510 ) of the value in bit position [0] and the pseudorandom bit from step 508 and produces a new 1-bit output.
[0077] Next, the system concatenates the value in bit positions [1 . . . n-1] with the value of the new 1-bit output (step 512 ) to produce a new n-bit string.
[0078] Next, the system stores the concatenated result into MainReg (step 514 ).
[0079] If not all rounds of the current phase are complete, the system proceeds to the next round (step 516 ), continuing with step 504 . Otherwise, the iteration ends.
[0080] FIGS. 4 and 5 illustrate the speed-up optimization for n-bit strings in accordance with some embodiments. As another, more realistic, example, consider FIG. 6 , which shows how to encrypt a U.S. Social Security number such as 348-88-2346 using a practical realization of the Thorp shuffle in accordance with some embodiments. After two rounds of enciphering, the result is 888-23-4606. In this embodiment, only two rounds are shown but there can be as many rounds as needed to ensure that the Thorp shuffle mixes the “deck” of U.S. Social Security numbers well.
[0081] Let us look at this enciphering more closely. U.S. Social Security numbers are enciphered using a tweaked cipher × × → where is the key space of the underlying pseudorandom function, and is a tweak space of byte strings, and is the space of all U.S. Social Security numbers. The previous embodiment is modified to accommodate base-10 characters instead of binary characters as follows. First, the n-bit register is replaced with a nine-character register. Second, the exclusive-or binary operation (which is really modulo-2 addition) is replaced with modulo-10 addition. Third, the pseudorandom function KT returns a base-10 character.
[0082] Suppose that a U.S. Social Security number 348882346 is stored in a register called MainReg 602 . The character string is divided into two parts: MainReg[0] and MainReg[1 . . . 8]. In round 1 ( 612 ), the system invokes the pseudorandom function KT 604 , passing in as arguments the round number 0 and the value of MainReg[1 . . . 8]=48882346. Suppose the invocation KT (0, 48882346) 604 returns the character 7 (one may think of this as rolling a ten-sided die). We compute the modulo-10 ( 606 ) addition of this character with the value in character position [0] to get 3+ 10 7=0. Next, we concatenate the value in MainReg[1 . . . n-1] (48882346) with the value of the output of the modulo-10 addition, 0, to produce a new character string, 488823460, and store it in register MainReg. After Round 1 ( 612 ), 348882346 has been encrypted to the intermediate value 488823460, as shown by the state of the 9-character register 610 .
[0083] We follow the same procedure outlined above for each subsequent round. For example, assuming KT (1, 888234606)=2, round 1 ( 618 ) yields the intermediate encryption 888234606 of 348882346 ( 616 ). This example illustrates how the described enciphering scheme can be used to encrypt messages in a small domain such as U.S. Social Security numbers to ciphertexts in the same domain. Since KT is bijective, it is guaranteed two encrypted Social Security numbers only collide if their corresponding plaintexts are identical.
[0084] Note that the process of enciphering n-digit decimal strings can be sped up in a manner similar to that which was illustrated in FIG. 4 for n-bit input strings. Rather than achieving a fivefold speed-up in the n-bit string case (measured in the number of AES calls), an embodiment for decimal strings achieves a twofold speed-up. FIG. 7 illustrates the process for applying the speed-up optimization to n-decimal-digit strings in accordance with some embodiments. (Why phases comprise two rounds over the domain of decimal-digit strings and not five rounds as for bit strings will become clear in a moment.)
[0085] FIG. 7 shows this speed-up optimization to encipher a message drawn from set where the total number of messages in set is N=10″ messages for some n≧2 in accordance with some embodiments. Each phase consists of two rounds. The message to encipher is an n-decimal-digit input string ( 712 ) stored in an n-decimal-digit register MainReg 714 .
[0086] To populate this SpeedUpReg 710 , one AES call ( 704 ) is made at the beginning of each phase as part of pseudorandom function KT 702 . This AES call ( 704 ) returns a pseudorandom 128-bit string. Since the SpeedUpReg stores decimal-digit strings, the system applies a conversion function that converts the 128-bit string to the corresponding 39-decimal-digit string, which is then stored in SpeedUpReg 710 . The two rounds making up a phase share the SpeedUpReg 710 to obtain their subsets of bits. The decimal-digits MainReg[2 . . . n] of the n-decimal-digit MainReg 714 are a decimal string Z 718 . The call AES K (P(i, Z)) is keyed with key K and takes as an argument, in one embodiment, a prefix-free encoding P(i, Z) of the phase number i and the string Z. Similar to the binary case, the speed-up optimization exploits the fact that substring Z is common to the n-decimal-digit strings contained in MainReg 714 during both rounds of the current phase. In particular, in one embodiment, AES is keyed with K and applied to a prefix-free encoding P(i, Z) of the phase number i and the string Z.
[0087] In each phase of the encryption of decimal-digit strings using the speed-up optimization for enciphering decimal-digit strings, the two rounds examine disjoint 10-digit subsets of the 39-decimal digits in SpeedUpReg. Accordingly, 19 digits of the 39-decimal digits in SpeedUpReg remain unused. Could we not also perform a third round and extract 10 of the 19 remaining decimal digits to index into? Unfortunately, this does not work. Over the course of three consecutive rounds of enciphering, the three states of n-digit register MainReg contain only a common (n-3)-digit substring Z To assure independent pseudorandom characters, we would therefore need to index with a 3-digit string B. However, there are 100 possible values for B, so that the pseudorandom function would need to provide at least 3·10 3-1 =300 digits, which is more than the 38 decimal digits obtained from the 128-bit string output we assume. In general, enciphering strings consisting of n base-k digits in phases comprising m rounds requires the pseudorandom function to output at least m·k m-1 base-k digits.
[0088] FIG. 7 shows the state changes of the n-decimal-digit register MainReg 714 for rounds j=0, 1 of some phase i. We label the contents of digit positions [0] as b 0 and [1] as b 1 , shown cross-hatched in FIG. 7 .
[0089] For example, consider the round 2i+j where j=0 ( 716 ). In MainReg 714 , bit b 0 is the active bit, which we assume to be 5. Bit b 1 is extracted to form a new bit string B 720 (shown to the right of the n-decimal-digit register as B=b 1 ). This bit string B, say B=6, is used to index into the SpeedUpReg 710 to obtain the pseudorandom base-10 character SpeedUpReg[B+10·j]=SpeedUpReg[6]. Suppose that the pseudorandom decimal digit at that position is 9. Note that with this index formula, both rounds in the phase use 10 different decimal-digits of the 39 decimal digits in the SpeedUpReg 710 .
[0090] Next, the system combines the value in decimal-digit position [0] with the pseudorandom decimal digit looked up from the SpeedUpReg 710 to produce a 1-decimal-digit output, which we denote by c 0 . The combining function is simply modulo-10 addition, so c 0 =9+ 10 5=4.
[0091] Next, the system concatenates the value in decimal-digit positions MainReg[1 . . . n-1] with c 0 and stores the concatenation result into the register MainReg 714 .
[0092] The new state of the register MainReg 714 in round j=0 is b 1 Z c 0 . To continue the example, consider the next round where j=1. The n-decimal-digit register MainReg 714 contains b 1 Z c 0 . Digit b 1 is the active digit. Digit c 0 is extracted to form a new string B 726 (shown to the right of the n-decimal-digit register MainReg). This string B 726 is used to compute the index B+10·j=14 into SpeedUpReg 728 to obtain one pseudorandom decimal-digit from the next 10-digit subset of the speed-up register.
[0093] Next, the system combines the value in decimal-digit position [0] with the pseudorandom decimal-digit looked up from the SpeedUpReg 710 to produce a 1-decimal-digit output c 1 . The combining function is again modulo-10 addition.
[0094] Next, the system concatenates the value in decimal-digit positions [1 . . . n-1] with the value of the 1-decimal-digit output of the combine function, and stores the concatenation result into the register MainReg.
[0095] The very last state shown in the figure is the end result of applying one two-round phase to the n-decimal-digit register 730: Zc 0 c 1 . If there are more phases remaining in the shuffle then the phase number is incremented by l and the next group of two rounds is computed. (Note that there may be fewer than two rounds in the very last phase).
[0096] FIG. 8 shows a flowchart illustrating a more general procedure of enciphering a message represented as an n-character string where each character is base-k digit in accordance with some embodiments. Note that the specific arrangement of steps shown in the figure should not be construed as limiting the scope of the embodiments. These embodiments include, but are not limited to, n-bit input strings, n-decimal-digit input strings, and n-hexadecimal-digit input strings.
[0097] The enciphering system begins the process by receiving (step 802 ) the message (a string of n base-k digits), the tweak (a byte string), and the key K. Each character is a base-k digit.
[0098] Next, the system stores the n-character input into an n-character first register MainReg (step 804 ).
[0099] Next, the enciphering system iterates over the first register MainReg in a numbered sequence of phases (step 806 ), modifying the state of MainReg. For each phase, the system performs the following.
[0100] Next, the system invokes the pseudorandom function KT (step 808 ) with two arguments: the phase number i and the value MainReg[1 . . . n-1] together with the phase number p. KT returns a pseudorandom base-k character string. Note that this pseudorandom function outputs a pseudorandom base-k character string of length l.
[0101] Next, the system selects at least m·k m-1 characters (step 810 ) for some m≧2 from the pseudorandom base-k character string output of the pseudorandom function KT and stores these selected characters in a second register SpeedUpReg. The second register SpeedUpReg behaves as the same speed-up register shown in FIG. 4 and FIG. 7 .
[0102] Next, the system iterates over the first register a sequence of m rounds (step 812 ). The last phase contains fewer rounds if the total number of rounds is not a multiple of m.
[0103] Next, the enciphering system applies a choice function (step 814 ) to the first register MainReg, the second register SpeedUpReg, and the round number to produce a pseudorandom base-k character output.
[0104] Next, the enciphering system combines the value in character position [0] of the first register and the pseudorandom base-k character output by the choice function to produce a new base-k character (step 816 ). Note that, in some embodiments, this combining function is modulo-k addition.
[0105] Next, the enciphering system (step 818 ) concatenates the value in character positions MainReg[1 . . . n-1] of the first register with the value of the new base-k character output and stores the result into the first register MainReg.
[0106] If there are more rounds (step 820 ), then the enciphering system goes to step 814 and continues with the process. Otherwise, if there are more phases ( 822 ), then the enciphering system goes back to step 808 and continues the process with the next phase.
[0107] When all phases are complete, the input string has been successfully enciphered. The ciphertext is contained in the first register MainReg.
[0108] FIG. 9 shows a flowchart elaborating the choice function given in step 814 of FIG. 8 in accordance with some embodiments. Note that the specific arrangement of steps shown in the figure should not be construed as limiting the scope of the embodiments. The enciphering system begins by invoking the choice function using the first register MainReg, the second register SpeedUpReg, and the round number as arguments to the function (step 902 ). What the system is doing, intuitively, is taking a pseudorandom character string—the output of the pseudorandom function stored conveniently in the SpeedUpReg —and “choosing” from a subset of the pseudorandom character string some character string that is, therefore, also pseudorandom.
[0109] Next, the enciphering system (step 904 ) extracts the (m-1) base-k characters string B from MainReg, where in round j, B is the concatenation of characters [1 . . . (m-1-j)] and characters [(n-j) . . . (n-1)] of MainReg.
[0110] Next, the enciphering system (step 906 ) interprets the string of m-1 base-k characters as a decimal number B and returns character [b+k m-1 ·j] of the SpeedUpReg to produce a pseudorandom base-k character output.
[0111] The following table gives some valid values for k, m, l satisfying the parameter constraint m·k m-1 ≦l.
[0000]
TABLE 3
Example parameter sets
Radix k
PRF output length l
Phase length m
2
128
5
3
65
3
8
16
2
10
39
2
16
8
2
[0112] The foregoing descriptions of embodiments have been presented for purposes of illustration and description only. They are not intended to be exhaustive or to limit the present description to the forms disclosed. Accordingly, many modifications and variations will be apparent to practitioners skilled in the art. Additionally, the above disclosure is not intended to limit the present description. The scope of the present description is defined by the appended claims. | Conventional block ciphers that traffic in 128-bit block sizes are ill-suited for operating in small domains like credit card numbers. Some embodiments relate to techniques for constructing and speeding up practical and provably secure schemes for deterministically enciphering data from a small domain like credit card numbers using a conventional block cipher or other pseudorandom function. | 7 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention is directed to an arrangement for suppressing noise and preventing faulty stitch formation in a sewing machine.
2. Description of the Prior Art
In sewing machines which are operable in either a cam controlled feeding mode or a manually controlled feeding mode, as described, for example, in U.S. Pat. No. 4,448,141 for "Sewing Machine Cam Controlled Feed Engaging and Disengaging Mechanism" of J. Szostak et al, issued May 15, 1984, it is essential that the feed regulating mechanism be lightly loaded during cam controlled feeding to prevent undue wear of the feed pattern cam, and that the feed regulating mechanism be additionally loaded during manually controlled feeding to prevent excessive and faulty stitch formation.
It is prime object of the present invention to provide a sewing machine, which is operable in either a manually controlled feeding mode or a cam controlled feeding mode, with an improved arrangement assuring an increased load on feed regulating mechanism during manually controlled feeding, and a decreased load during cam controlled feeding.
It is another object of the invention in a sewing machine, which is operable in either a manually controlled feeding mode or cam controlled feeding mode, to provide for the movement of a spring into loaded engagement with a feed regulating control member when mode selecting mechanism is disposed for manual control, and out of loaded engagement when the mode selecting mechanism is disposed for cam controlled feeding.
Other objects and advantages of the invention will become apparent during a reading of the specification taken in connection with the accompanying drawings.
SUMMARY OF THE INVENTION
A sewing machine in accordance with the invention includes a feed regulating cam, a follower for the cam, a manual control with a plunger, and mechanism responsive to the manual control for operably connecting a feed regulating control lever to the cam follower for movement thereby, and for disconnecting the control lever therefrom for movement by the plunger. A spring urges the cam follower with a light biasing action against the cam while the control lever is operably connected to the cam follower, and biases the lever toward a position of engagement with the plunger. An additional spring is affixed to said connecting mechanism for movement thereby into a position to engage and load the control lever along with the first mentioned spring against the plunger as the mechanism is moved by the manual control to disconnect the control lever from the cam follower, and for movement by the mechanism away from the control lever as said mechanism is moved by the manual control to operably connect the control lever and cam follower.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a front perspective view of a portion of a sewing machine bracket arm which has been cut away to shown the arrangement of the invention;
FIG. 2 is a side elevational view taken substantially on the plane of the line 2--2 of FIG. 1 and showing the sewing machine bracket arm in vertical cross section;
FIG. 3 is a cross-sectional view taken substantially on the plane of the line 3--3 of FIG. 2, and showing mode selecting parts disposed in a manually controlled feeding position;
FIG. 4 is a fragmentary top view taken substantially on the plane of the line 4--4 of FIG. 3;
FIG. 5 is a view similar to FIG. 3 showing the mode selecting parts disposed for cam controlled feeding; and
FIG. 6 is a fragmentary top view taken substantially on the plane of the line 6--6 of FIG. 5.
DESCRIPTION OF THE PREFERRED EMBODIMENT
This invention is applicable to a sewing machine having any conventional work feeding mechanism which is capable of regulation to vary the magnitude and direction in which the work fabrics are fed, and particularly those in which manual regulation of the work feed is accomplished by means of a rotary element such as a dial or the like. U.S. Pat. No. 3,753,411, Aug. 21, 1973 of Graham et al, which illustrates one such sewing machine is incorporated herein by reference.
As shown in the accompanying drawings, reference character 11 indicates the frame of a sewing machine in which a main drive shaft 12 is journaled. Fast on the main drive shaft 12 is a constant breadth cam 13 which is embraced by the bifurcated head 14 of a feed advance drive pitman 15. Pivotally secured on a pin 16 to the pitman 15 is a slide block 17 constrained in a guide slot 18 of a feed regulating block 19 which is pivotally supported on a pivot pin 20 which is affixed in the machine frame. The angular position of the feed regulating block determines the magnitude and direction of fabric feed. Since any conventional work feeding mechanism such as a four-motion drop feed mechanism may be used with this invention, a complete sewing machine work feeding mechanism is not shown in the accompanying drawings.
A pin 30 secured to the feed regulating block 19 in spaced relation to the pivot pin 20 is embraced by a slot 31 formed in a lever 32 which is fulcurmmed on a pin 33 fixed in the machine frame 11. The lever 32, which thus influences the angular position of the feed regulator block 19, is formed with a downturned arm 34 and an upturned arm 35. A lightly loaded torsion spring 36, having opposite ends 38 and 39 affixed in pin 20 and engaged with lever 32 respectively, biases the lever toward engagement on downturned arm 34 with a manually influenced control part, as will be described below, and toward engagement on upturned arm 35 with a pattern cam influenced control which will also be described below.
The manually influenced control, as best illustrated in FIGS. 1 and 2 of the drawings, includes an operator influenced dial 40 journaled in the frame 11 of the sewing machine and formed integrally with a cylindrical boss 41 having a face cam surface 42 engaged by a follower 43 which is carried on a spring biased sleeve 49. An arm 45 on the follower slidably engages a guide 46 carried in the machine frame. The face cam surface 42 includes a dwell segment 47 which extends for approximately 30 degrees of the cylindrical boss 41 and which when tracked by the follower 43, dictates that the work feed regulation be maintained in maximum stitch length in the forward direction. The manually influenced control also includes an axially shiftable pushbutton 48 for rapidly moving a plunger 44 to the left as viewed in FIG. 2 to provide a quick feed reverse. The plunger 44 is engageable with the downturned arm 34 of the lever 32.
Referring to FIG. 1, the upturned arm 35 of the lever 32 extends in the path of movement of an arm 50 of a bell crank 51 fulcurmmed on a pin 52 carried in the machine frame 11. The other arm 53 of the bell crank lever 51 is formed with a radial slot 54 having a flaired mouth 55.
A pin 56 depending from connecting link 57 is adapted selectively to be shifted into and out of bell crank lever slot 54 as will be described hereinbelow. The connecting link 57 is pivoted by a shouldered screw 58 to a pattern cam follower lever 59 sustained on a pivot pin 60 in the machine frame and formed with a cam follower finger 61 adapted to track the periphery of a plastic feed controlling pattern cam 62 fast on a cam shaft 63 driven from the main drive shaft 12.
For selectively connecting or disconnecting the feed pattern cam follower lever 59 and the link 57 with the lever 32 which influences the stitch length and direction of work feed, a sleeve 65 is secured to the cylindrical boss 41 of the manual stitch length regulating dial 40. The sleeve includes a flange 67 with an outer cylindrical surface 68, and a base portion 69 with an outer cylindrical surface 70. A radial cam lobe 71 occupies a small angular segment, which need not exceed 30 degrees, of sleeve 65.
Fingers 80 and 81, formed on a follower lever 82 which is fulcurmmed on a pin 83 carried in the machine frame, track a sloped surfacce 84 on cam lobe 71 and a sloped surface 85 on flange 67, respectively, to positively connect lever 32 with cam follower lever 59 and link 57 for operation thereby while the dwell segment 47 of the face cam 42 is effective. At other times, fingers 80 and 81 track surfaces 70 and 68, respectively of sleeve 66 to prevent operation of lever 32 by cam follower lever 59 and link 57. An upturned arm 86 on follower lever 82 includes an offset finger 87 engageable with a rock arm 88 which is journaled on pin 83. A compression spring 89 constrained between a seat 90 formed on the follower lever 82, and a seat 91 formed on the rock arm 88 biases the rock arm toward the offset finger 87. The rock arm terminates in a circular head 92 which is embraced between flanges 93 depending from one arm 96 of a bell crank 97 pivoted on a pin 98 in the machine frame. A second arm 99 of the bell crank 97 is formed with a radial slot 100 which embraces the pin 56.
As the operator influenced control member 40 is shifted into the range in which the dwell segment 47 of cam 42 is effective, finger 81 slides down sloped surface 85 on flange 67, and the sloped surface 84 of cam lobe 71 acts positively on finger 80 to engage the feed pattern cam control with the work feed regulator by swinging the pin 56 on link 57 into slot 54 of bell crank lever 51. As the operator influenced control member 40 is shifted out the range in which the dwell segment 47 of cam 42 is effective, finger 80 slides back down the cam lobe surface 84 and the sloped surface 85 of flange 67 acts positively on finger 81 to disengage the feed pattern cam control from the work feed regulator by swinging pin 56 on link 57 out of a slot 54 of the bell crank.
A coil spring 110 is adjustably secured to bell crank 97 for movement therewith. The spring coils encircle pin 98, and a lower end tang 111 engages wall 113 of the bell crank 97. The spring includes an extended portion 114 which is engaged by the head 115 of a screw 116 that is threaded into wall 113. The screw may be adjusted to contract or permit expansion of the spring coils while tang 111 is in engagement with wall 113, and in this way extended portion 114 of the spring may be adjusted to predetermine the extent to which the spring shall be capable of loading lever 32.
Spring 110 is positioned by bell crank 97 to cause the upper end 117 of spring portion 114 to engage and load lever 32 at arm 35 with a biasing force, according to the adjustment of screw 116, when the feed pattern control is disconnected from lever 32 and manual control is in effect (FIGS. 3 and 4). Spring 110 then supplements the effect of light loading torsion spring 36 to maintain lever 32 in engagement with plunger 44 at downturned arm 34. The spring thereby prevents chatter due to vibrational forces which tend to cause the lever 32 to bounce against the plunger when pushbutton 48 is fully depressed to effect a quick feed reversal during operation of the machine. The spring also prevents the shortening of stitches during manual control in all dial controlled positions of the plunger 44 while multiple layers of heavy material are sewn and vibrational forces are thereby created tending to move lever 32 out of contact with plunger 44.
When dial 40 is disposed to engage the feed pattern control with the work feed regulator, spring 110 is positioned by bell crank 97 to separate spring end 117 from lever 32 (FIGS. 5 and 6). During feed pattern controlled operations, plunger 44 is in the maximum stitch length position, that is furthest to the right as viewed in FIG. 2, and lever 32 is held apart from the plunger by cam 62 acting through connecting linkages. The lever is then held in engagement with the feed pattern control at arm 50 by the force of the light loading torsion spring 36 which is sufficient to maintain cam follower finger 61 in engagement with plastic cam 62 without causing undue wear of the follower engaging surface of the cam.
It is to be understood that the present invention relates to a preferred embodiment of the invention which is for purposes of illustration only, and is not be be construed as a limitation of the invention, Numberous alterations and modifications will suggest themselves to those skilled in the art, and all such modification which do not depart from the spirit and scope of the invention are intended to be included within the scope of the appended claims. | A sewing machine which is operable in either a cam controlled feeding mode or a manually controlled feeding mode is provided with a spring which is moved into loading engagement with a feed regulating control lever by mode selecting mechanism when the selecting mechanism is disposed for manual control, and is moved away from the feed regulating control lever when the selecting mechanism is disposed for cam controlled feeding. | 3 |
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of priority under 35 U.S.C. §119(e) of U.S. Provisional Application No. 61/619,872, filed on Apr. 3, 2012, the entirety of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present disclosure generally relates to building construction materials and methods, and more particularly relates to composite fiber cement cladding with improved properties and methods of installing such material.
2. Description of the Related Art
The future of building construction is moving towards providing an insulated, energy efficient building envelope. In particular, there is an increasing demand for energy efficient residential and commercial constructions which require walls having greater building insulation ratings. The R-value of building insulation is a measure of its resistance to transferring heat or thermal energy. Greater R-values indicate more effective building insulation. The higher the R-value of the insulation of a building, the easier it is to maintain a temperature differential between the interior and the exterior of the building over an extended period of time. One approach to improving the energy efficiency of a building structure is to add insulation to the exterior walls. Adding additional wall insulation, however, can drive up the cost of construction as it requires additional material and installation labor. Adding additional exterior wall insulation can adversely affect the aesthetics, water management, and other properties of the wall structure assembly, as well as impact the design of other components of the wall.
Foamed material is one type of material that can be used to insulate building structures. While foamed material has been used as an insulation material in certain building construction, it has not been used as efficiently and effectively as it could be. For example, foam sheathing or backing boards have been placed between the framing and fiber cement exterior sidings of a building structure to provide additional insulation. The foam sheathing or backing boards are typically tacked or fastened to the framing prior to installation of the exterior cladding. To reduce the amount of air exchanged between the inside and the outside of the building structure, the seams of the foam sheathing or backing boards often need to be sealed or taped. As such, the installation of the foam sheathing requires additional processing steps. The foam installation may also create aesthetic issues with the exterior siding, such as causing a wavy appearance as when siding is installed over deformations in the foam where fasteners compress the underlying foam.
Additionally, in high-wind regions, sidings are frequently blown off walls of building structures. To improve wind resistance, shims are often used to create a uniform and flat surface for attachment of the sidings so as to reduce gaps that could catch the wind. Face nailing instead of blind nailing is also recommended, particularly for fiber cement sidings in regions with high wind speed. However, these existing methods for enhancing wind resistance of sidings require additional material and labor, and can detract from the aesthetics of exterior building structure.
In view of the foregoing, there is a need for a different building construction material and technique for improving the insulation of building structures and improving the wind resistance of exterior sidings. There is also a need for an improved fiber cement composite insulation building material designed without the shortcomings of existing site assembled systems that incorporate foam as an insulating material.
SUMMARY OF THE INVENTION
Accordingly, disclosed herein are integrated fiber cement and foam cladding systems that incorporate foam or similar light weight material, such as lightweight mats of fiberglass or Rockwool, for improving the insulation capacity of a cladding material. In various embodiments, the integrated fiber cement and foam cladding system is designed to improve existing uses of foam and fiber cement during the construction of a wall or other structure in one or more of the following areas: reduced installation time, increase wind loads, simplified assembly, nail holding ability, resistance to thermal bridging, water management, and transportation. As used herein, the terms “foam” or “foamed material” are broad terms and shall have their ordinary meaning and shall include, but not be limited to polymeric foams, inorganic foams, cementitious foams, glass foams, ceramic foams, metallic foams, aerogels, syntactic foams and the like in a substantially solid state.
In one application, the integrated fiber cement and foam system of the present disclosure is prefabricated and designed with a structure that has sufficient integrity to sustain its connection with the building frame under high wind loads.
Accordingly, in one embodiment of the invention, there is provided a prefabricated integrated fiber cement and foam insulation panel comprising: a fiber cement layer having a front side and a back side spaced apart to define an intermediate portion and an edge member extending around the intermediate portion; a foam layer having a front side and a back side spaced apart to define an intermediate portion and an edge member extending around the intermediate portion; and an adhesive layer disposed between the fiber cement layer and the foam layer, said adhesive layer adapted to attach the fiber cement layer to the foam layer.
In a further embodiment of the invention, the foam layer is configured to facilitate alignment and assembly of multiple panels together. In one implementation, the foam layer is profiled with an interlocking feature such that adjacent foam layers will interlock when the siding panels are installed. This interlocking feature facilitates alignment of the siding panels, inhibits the infiltration of air and water between the panels and also increases wind loads on the structure by improving the resistance of the panels to the effects of strong winds impinging on the wall.
Accordingly, in a further embodiment of the invention, there is provided an exterior cladding system for building structures. The system comprises a first panel and a second panel, wherein each panel comprises a fiber cement layer and a foam layer, the fiber cement layer of each panel being secured to the respective foam layer, the foam layer of each panel comprises interlocking means. In one embodiment of the invention the interlocking means comprises a receiving channel or mating channel whereby the receiving channel or mating channel of the foam layer of the first panel engages with the receiving channel or mating channel of the foam layer of the second panel when the first and second panel are placed in a contiguous arrangement such that at least a portion of the receiving or mating channel of each of the foam layers abut in an interlocking arrangement.
In a further embodiment of the invention the fibre cement layer is secured to the foam layer by means of an adhesive layer. It is to be understood that any other suitable type of securing means known to a person skilled in the art could also be used. Preferably the method of securing the fibre cement layer to the foam layer allows for thermal cyclic differential expansion between the fibre cement layer and the foam layer and or any other layers which may be present.
Accordingly, in a further embodiment of the invention, there is provided an exterior cladding system for building structures. The system comprises a first panel and a second panel, wherein each panel comprises a fiber cement layer and a foam layer, wherein the fiber cement layer of each panel is pre-attached to the respective foam layer by an adhesive selected to accommodate the stresses generated by cyclic differential expansion between the fiber cement layer and the foam layer, wherein the foam layer of the first panel comprises an elongate mating channel defined by two opposing sidewalls formed along a longitudinal edge of the foam layer of the first panel, wherein the foam layer of the second panel comprises an elongate protrusion formed along a longitudinal edge of the foam layer of the second panel, the protrusion on the foam layer of the second panel being configured to be received into the mating channel on the foam layer of the first panel in a manner such that the sidewalls formed on the foam layer of the first panel enclose the protrusion formed on the foam layer of the second panel in a manner such that the foam layer of the first and second panels interlock.
In a further embodiment of the invention, the fiber cement layer is configured to facilitate alignment and assembly of multiple panels together. In one implementation, the fiber cement layer is profiled with an interlocking feature such that adjacent fiber cement layers will interlock when the siding panels are installed. It is to be understood that in other embodiments of the invention the foam layer of the exterior cladding system can be configured such that the interlocking means is located on any two opposing edges of the foam layer. In an alternative embodiment of the invention the interlocking means can be located on at least two opposing edges of the foam layer.
Conveniently in a further embodiment of the invention, the foam layer comprises an interlocking feature extending around at least a portion of the edge member to facilitate alignment and assembly of the multiple panels together. In a further embodiment of the invention, the interlocking feature is configured to improve the wind load of the installed prefabricated integrated fiber cement and foam insulation panel. In one embodiment of the invention, the interlocking feature comprises complementary shaped tongue or groove configurations. In a further embodiment of the invention, the foam layer is configured to interlock with adjacent foam layers in a manner such that the integrated fiber cement and foam insulation panels are arranged in a nested configuration.
In yet another application, the integrated fiber cement and foam system provides foam backed siding planks that provide the functional equivalent of continuous insulation and a thermal break across the framing members. In yet another embodiment, the integrated fiber cement and foam system is configured to form a substantial air seal between the individual components of the system. In yet another arrangement, the integrated fiber cement and foam system provides a foamed back lap or panel siding that allows the installer the flexibility to adjust the joints between individual laps or panels and yet maintain a sealed air barrier. In yet another application, the integrated fiber cement and foam system is designed to aid in the placement of fasteners.
In yet another arrangement, the integrated fiber cement and foam system is designed with a continuous, uninterrupted drainage plane and can prevent water from being trapped between the foam layer and wall sheathing which normally surrounds the structural support of the building structure. In one embodiment of the invention, either the foam layer or the fiber cement layer is configured with one or more drainage channels to provide a drainage plane. In other implementations, drainage channels are formed either on the interior or exterior surface of the foam layer or within the foam layer itself for effective water management within the wall cavities. In a further embodiment of the invention, a plurality of drainage channels are formed in the foam layer of the integrated fiber cement and foam insulation panel. In a further embodiment of the invention, a plurality of drainage channels are formed on at least one of the surfaces of the foam layer of the integrated fiber cement and foam insulation panel. In a further embodiment of the invention, a plurality of drainage channels are formed inside the foam layer of the integrated fiber cement and foam insulation panel. In a further embodiment of the invention, a plurality of drainage channels are formed on at least one of the surfaces of the fiber cement layer of the integrated fiber cement and foam insulation panel. In a further embodiment of the invention, a plurality of drainage channels are formed inside the fiber cement layer of the integrated fiber cement and foam insulation panel. In a further embodiment of the invention the integrated fiber cement and foam insulation panel, at least one surface of the foam layer is provided with a pattern which provides a series of drainage channels in the integrated fiber cement and foam insulation panel. The pattern can adopt any suitable form, for example, a Chevron pattern or a plurality of repeating emblems or logos. In a further embodiment of the invention the foam layer is porous. Conveniently, the foam layer is sufficiently porous to permit water drainage.
In a further embodiment of the invention, the integrated fiber cement and foam insulation panel comprises a fiber cement layer and a foam layer, wherein the width of the foam layer is smaller than the width of the fiber cement panel so as to form an overhang on the integrated fiber cement and foam insulation panel.
In a further embodiment of the invention, the integrated fiber cement and foam insulation panel further comprises a reinforcement mesh layer. In one embodiment of the invention, the integrated fiber cement and foam insulation panel further comprises a reinforcement mesh layer embedded in said foam layer. In a further embodiment of the invention, the integrated fiber cement layer and foam insulation panel further comprises a reinforcement mesh layer intermediate the fiber cement layer and the foam insulation layer. In a further embodiment of the invention, the integrated fiber cement layer and foam insulation panel further comprises a reinforcement mesh layer embedded in the fiber cement layer, intermediate the fibre cement layer and the foam insulation layer. In a further embodiment of the invention, the integrated fiber cement and foam insulation panel further comprises one or more fastening tabs. In a further embodiment, the one or more fastening tabs are disposed between the foam layer and the fiber cement layer. In another embodiment, the one or more fastening tabs are disposed on and/or adjacent to the back side of the foam layer. In a further embodiment, the one or more fastening tabs are attached to the panel in a manner such that a portion of each tab extends outwardly from the lateral edges of the foam layer.
In an embodiment, a method of installing integrated fiber cement and foam insulation panels on a building structure having a framing comprises the steps of: installing one or more starter strips at the base of a wall of the building to form a plank angle; and installing the fiber cement and foam insulation panels sequentially up the wall. In an embodiment, the method further comprises the steps of crotchedly vertically nesting the fiber cement and foam insulation panels. In an embodiment, the method further comprises the steps of installing an insert behind a butt joint intersection between adjacent fiber cement and foam insulation panels; wherein the insert comprises a foam layer with the same profile as a foam layer in the fiber cement and foam insulation panels as a flashing layer. In a further embodiment, wherein the fiber cement and foam insulation panel comprises one or more fastening tabs, the method further comprises the steps of installing the panels to the framing by attaching the one or more fastening tabs to the framing, wherein the fastening tabs are attached to the fiber cement and foam insulation panels in such a manner that at least a portion of each fastening tab is concealed from view when the panels are installed on the building structure.
In yet another application, the integrated fiber cement and foam system is configured to be stacked in a manner during transit so as to reduce damage normally sustained by foam materials while in transit.
In some embodiments, the integrated fiber cement and foam insulation system comprises a prefabricated fiber cement and foam insulation siding panel. The prefabricated panel includes a fiber cement layer and a foam layer attached thereto, preferably by an adhesive. The fiber cement layer can be a panel, a plank, a shingle, a strip, a trim board, or the like. In a further embodiment of the invention the fiber cement and foam insulation siding panel comprises an oriented strand board (OSB), said OSB is attached to the foam layer on the opposing side of the fiber cement layer. Various embodiments of the integrated fiber cement and foam insulation system will be described in greater detail below.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1A-1B illustrate an integrated fiber cement foam and insulation siding panel according to one embodiment of the present disclosure.
FIGS. 2A-2C illustrate an integrated fiber cement foam and insulation siding panel according to another embodiment of the present disclosure.
FIGS. 3A-3I illustrate embodiments of foam layer profiles that can be incorporated in an integrated fiber cement and foam insulation panel.
FIGS. 3J-3N illustrate profiles of foam starter strips of various embodiments.
FIG. 4A-4D illustrates an embodiment of integrated fiber cement and foam insulation panels incorporating drainage features of various embodiments.
FIG. 5 illustrates an integrated wall assembly according one embodiment of the present disclosure.
FIG. 6A-6I illustrate various embodiments of an integrated fiber cement and foam insulation panel with integrated fastening tabs.
FIG. 7 illustrates yet another embodiment of the present disclosure showing a prefabricated integrated fiber cement and foam insulation panel with a backing disposed on the backside of the foam layer.
FIG. 8 illustrates yet another embodiment of the present disclosure showing an integrated fiber cement and foam insulation system that incorporates a discontinuous layer in the foam backing for acoustic dampening purposes.
FIG. 9 illustrates an embodiment of the present disclosure showing a fiber cement and foam insulation panel designed for high shear applications.
FIGS. 10A-10C illustrate embodiments showing two fiber cement and foam insulation panels joined together with a butt joint.
FIGS. 11A and 11B illustrate certain connection mechanisms that can be used to join adjacent integrated fiber cement and foam panels at a butt joint.
FIG. 12 depicts a flow diagram of installation of fiber cement and foam insulation plants according to one embodiment.
FIG. 13 depicts yet another embodiment of an integrated fiber cement and foam insulation panel.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
References will now be made to the drawings wherein like numerals refer to like parts throughout. FIG. 1A illustrates an integrated fiber cement and foam insulation panel 100 configured for exterior siding applications in accordance with various embodiments of the present disclosure. The panel 100 generally includes a fiber cement layer 102 and a profiled foam layer 104 attached thereto. The fiber cement layer 102 can be in the form of a plank, a siding, a shingle, a strip, a trim board, or various other building components. In a preferred embodiment, the fiber cement layer 102 is configured as a siding used for exterior wall applications. The profiled foam layer 104 can be made of open-celled and/or closed-celled foam or other similar lightweight material with insulating material properties, such as polystyrene foam, mineral based foams, foamed cement or gypsum, phenolic foams, and aerogels. Additionally or alternatively, the profiled foam layer 104 may also comprise mineral fibers or fiberglass, cellulose, polyisocyanurate, polystyrene, polyurethane, cotton fibers, and mineral wool. The profiled foam layer 104 may also include as part of its formulation water repellent agents, fire retarding agents, termiticides, insecticides or repellents, gases that enhance R-value retention, fillers that enhance R-value and the like. In some embodiments, the profiled foam layer 104 may be a composite foam comprised of materials with differential composition, density, compressive strength or fastener holding ability. As shown in FIG. 1A , the profiled foam layer 104 is adhered to an interior surface or backside 105 of the fiber cement layer 102 and extend substantially across the length of the fiber cement layer 102 such that the profiled foam layer can provide continuous insulation and thermal break across between the fiber cement layer and framing members upon installation of the panel 100 . Preferably, the profiled foam layer 104 extends partially across the width of the fiber cement layer 102 so as to leave an overhang portion 108 . The overhang portion 108 is adapted to overlap with adjacent panels when the panels are installed in a nesting configuration. In other embodiments, the profiled foam layer 104 does not extend across the entire length of the fiber cement layer 102 so as to accommodate possible expansion of the foam due to thermal effects upon installation of the panel 100 .
In various embodiments, a specially formulated adhesive layer 106 is uniformly disposed between the interior surface 105 of the fiber cement layer 102 and the profiled foam layer 104 to form a strong and uniform bond between the foam and the fiber cement across the entire panel 100 . The adhesive layer 106 is preferably formulated to establish an effective chemical and/or mechanical interlocking bond with both the foam and the fiber cement. In one embodiment, the adhesive layer 106 may be made of polyurethane, poly urea or isocyanate based materials. Preferably, the adhesive layer when bonding styrene foam to fiber cement is a high-shear strength adhesive that will not attack or eat away at either the fiber cement or styrene foam. Preferably, the adhesive layer will offer a durable bond between the fiber cement and foam layers in a variety of environmental condition including cold and warm conditions, dry and wet conditions, and freeze-thaw conditions, with salt, and in alkaline solutions, etc. The adhesive layer also preferably maintains its adhesive properties through exposure to many cycles of temperature swings (hot to cold), moisture conditions (wet to dry), and/or freeze-thaw cycles.
In one embodiment, the adhesive layer can be made of a water based adhesive, solvent based adhesive, and 100% solid. The adhesive layer can be formed in a liquid form, in a paste form, and/or in a solid form as hot melt adhesive. The chemistries can include one and two component polyurethane, one and two part epoxy, polyvinyl acetate, polyolefin, amorphous polyolefin, pressure sensitive polyolefin, poly ethylene vinyl acetate, and/or polyamide. In some embodiments, the adhesive may be a hot melt or reactive hot melt adhesive. In such embodiments, it is preferable that the hot melt adhesive establishes a very quick bond so that the fiber cement product bonded with foam can be moved and stacked in production.
In a preferred embodiment, the adhesive layer 106 is selected to accommodate the possible stresses generated by cyclic differential expansion between the foam and the fiber cement portions of the integrated fiber cement and foam insulation panel. In various embodiments, the adhesive can be applied onto the fiber cement layer by spraying, roll coating, etc. The adhesive layer 106 may be discontinuous, such as with partial coverage over the portion of the back surface 105 of the fiber cement layer 102 which mates to the profiled foam layer 104 to lead to a material and cost savings. A discontinuous adhesive layer 106 may also facilitate the evaporation of moisture from the interface between the elongate fiber cement layer 102 and the profiled foam layer 104 . In other embodiments, the adhesive layer 106 may be continuous, such as with full coverage over the portion of the back surface 105 of the fiber cement layer 102 which mates to the profiled foam layer 104 .
In another embodiment, the profiled foam layer 104 may be joined to the fiber cement layer 102 by laminating the profiled foam layer 104 to the interior surface or back face 105 of the fiber cement layer 102 . Lamination may be achieved by mechanical means, by use of adhesives or by forming the foam layer directly on the fiber cement layer either before or after curing of the fiber cement layer by autoclaving, depending on the materials used. In yet another embodiment, the profiled foam layer 104 can be formed by applying a layer of foam generating liquid to the interior surface or back face 105 of the fiber cement layer 102 and allowing the layer of foam generating liquid to expand such that the entire interior surface or back face 105 of the fiber cement layer 102 is substantially covered with foam. In this embodiment, the profiled foam layer 104 may be formed into a predetermined shape and profile after foam generation by use of routing, molding or machining equipment as is known to those skilled in the art. Alternatively, the profiled foam layer 104 may be formed by allowing the layer of foam generating material to expand into a mold or container of a predetermined shape or profile, followed by an operation that releases the foam layer from the mold or container.
With further reference to FIG. 1A , in various preferred embodiments, the profiled foam layer 104 can include drainage channels 112 extending through the exterior or interior of the foam to provide water drainage. The profiled foam layer 104 can also include profiled opposing longitudinal edges 110 , 111 . The profiled edges 110 , 111 are configured to interlock with corresponding profiled edges on adjacent profiled foam layers to facilitate alignment of the panels 100 during installation. In certain implementations, the interlocking features formed by the edges 110 , 111 of the profiled foam layer 104 are adapted to allow the panels 100 to nest with each other as they are assembled on a wall.
As described in greater detail below, in some embodiments, the interlocking features are specially configured to interlock in a manner that improves the wind load of the panels. As shown in FIG. 1A , one of the edges 111 of the profiled foam layer 104 is configured with a channel 115 defined by two parallel sidewalls 114 a , 114 b extending longitudinally across the edge 111 . The parallel sidewalls 114 a , 114 b in conjunction with the channel 115 formed in the profiled foam layer 104 interlock and secure the edge 110 of adjacent foam layers so as to improve wind resistance of the panel 100 . The interlocking features can also be adapted to provide an air seal, whether with or without use of sealants such as caulk or tape. In some embodiments, the interlocking feature can also be adapted to meet the requirements for continuous insulation and thermal break across the framing members. In some implementations, the interlocking features are also adapted to provide the installer a means to adjust joint spacing so as to efficiently space panels along the wall to reduce material use and installation labor.
FIG. 1B illustrates a manner in which a plurality of integrated fiber cement and foam insulation panels 100 a , 100 b can be arranged as assembled on a building frame to form an exterior cladding, such as for exterior siding applications. In various preferred embodiments, the panels 100 a , 100 b are prefabricated so that the installer can simply remove the packaging from each panel and attach the panels to the frame of a building. As shown in FIG. 1B , the panels 100 a , 100 b are positioned in a nesting configuration whereby the profiled edges 110 a , 111 a , 110 b , 111 b of the foam layers 104 a , 104 b interlock the panels so as to provide an air seal without sealer and to facilitate alignment and installation. The panels can be positioned such that the interlocking foam layers can provide continuous insulation and thermal break across the building framing members. As also shown in FIG. 1B , the drainage channels 112 allow water to drain from the interior of the panels 100 a , 100 b . The drainage channels 112 can be formed either on the interior or exterior surface of the foam layer or within the foam layer itself for effective water management within the wall cavities. In one implementation, the profiled foam layer 104 has a thickness of about ¼ inch to 3 inches (0.635 cm to 7.62 cm) and the fiber cement layer 102 has a thickness of about ⅛ inch to 1.25 inches (0.318 cm to 3.175 cm). In one embodiment, the profiled foam layer 104 can have a density of between 1.25 to 2.0, such as 1.25, 1.5, 1.75, or 2.0, and an R value of between R3 and R7, preferably R3, such as R3, R5, and R7.
With further reference to FIG. 1B , in overlapping siding applications, the parallel side walls 114 a , 114 b on the lower edge 117 a of the profiled foam layer 104 a directly contact and enclose both side surfaces of the upper edge 119 b of the adjacent profiled foam layer 104 b , thus mechanically connecting the profiled foam layers 104 a , 104 b with each other, which in turn improve the wind load of the panels 100 a , 100 b . In one embodiment, both the upper and lower edges 117 a , 117 b , 119 a , 119 b of the profiled foam layers 104 a , 104 b have a sloped profile such that the parallel side walls 114 a , 114 b are not evenly disposed. Preferably, the sidewall 114 b in contact with the fiber cement layer 102 a , 102 b is positioned higher than the sidewall 114 a , 114 b not in direct contact with the fiber cement layer.
FIG. 2A illustrates an integrated fiber cement foam and insulation panel 200 according to another embodiment of the present disclosure adapted for exterior siding applications in which the sidings are not in a nesting configuration. As shown in FIG. 2A , the panel 200 includes a fiber cement layer 202 and a profiled foam layer 204 attached thereto. The profiled foam layer 204 can be attached to the fiber cement layer 202 by an adhesive layer 206 or can be integrally formed on the fiber cement layer 202 . In this embodiment, the longitudinal edge 209 of the profiled foam layer 204 is substantially flush with the longitudinal edges 207 of the fiber cement layer 202 . As also shown in FIG. 2A , the foam layer 204 has interlocking features 210 , 211 adapted for aligning and coupling adjacent panels 200 during assembly, such as a tongue and groove joint. Additionally, drainage channels 212 can be formed in the foam layer 204 as shown in FIG. 2A . In certain preferred implementations, the thickness of the foam and fiber cement layers can be selected to provide target insulation R values and also allow the panels to be integrated into the building structure without requiring alterations of the wall or framing dimensions of existing building structures. In one implementation, the foam backing 204 has a thickness of about ¼ inch to 3 inches (0.635 cm to 7.62 cm) and the fiber cement layer has a thickness of about ⅛ inch to 1.25 inches (0.318 cm to 3.175 cm). In one embodiment, the foam backing 204 can have a density of between 1.25 to 2.0, such as 1.25, 1.5, 1.75, or 2.0, and can have an R value of between R3 and R7, preferably R3, such as R3, R5, and R7. In one embodiment, siding nails from 6 d to 16 d can be used, such as 6 d , 10 d , and 16 d.
FIG. 2B illustrates one embodiment in which integrated fiber cement and foam insulation panels 200 can be arranged when they are assembled on a building frame to form an exterior cladding. As shown in FIG. 2B , the foam layers 204 a , 204 b can include interlocking features 210 ′, 211 ′ such as a tongue and groove, such that the fiber cement layers 202 a , 202 b form a substantially planar exterior surface. In some embodiments, the interlocking features in the foam layers may be formed using the same techniques as for forming drainage channels in a separate step. In addition, in the case of EPS foams, the polystyrene beads may be placed in a mold specifically designed to yield a foam panel having both drainage channels and interlocking features.
FIG. 2C shows an alternative embodiment in which the integrated fiber cement and foam insulation panels can be arranged when they are assembled on a building frame to form an exterior cladding. As shown in FIG. 2C , the fiber cement layers 202 a , 202 b can include interlocking features 210 ″, 211 ″ such that the fiber cement layers 202 a , 202 b form a substantially planar exterior surface. In the illustrated embodiment in FIG. 2C , the profiled foam layers 204 a , 204 b are configured without interlocking features. It should be appreciated that in various embodiments, either the profiled foam layers 204 a , 204 b and/or the fiber cement layers 202 a , 202 b can have interlocking features 210 , 211 .
In various embodiments, the fiber cement and foam insulation systems disclosed herein are designed with innovative water management mechanisms and improved ventilation functions to facilitate ventilation and drainage of water and other liquids from the wall cavity. As shown in FIG. 1A , the foam layer 104 may incorporate various drainage channels 112 . The drainage channels are designed to divert water away from the panels so as to prevent water from entering the home, prevent damage to the panels, and prevent the panels from attracting insects.
FIGS. 3A-3I are schematic illustrations of certain embodiments of the profiled foam layer 104 that is part of the integrated fiber cement foam and insulation panel 100 . In some embodiments, the profiled foam layer 104 has a first face 131 that is configured to be in direct contact with a fiber cement panel and an opposing face 133 that is set at an angle relative to the first face 131 so as to form an inclined surface relative to the fiber cement layer. The inclined surface facilitates mounting of the panels in a nesting configuration. In some other embodiments, the profiled foam layer 104 can be configured to allow stacking of the integrated fiber cement and foam panels during transit so as to reduce damage otherwise normally sustained by foam materials while in transit. As illustrated in FIGS. 3A-3D , the profiled foam layer 104 can include complementary angled edges to facilitate nesting. In one embodiment, an angle 134 measuring about 45 degrees relative to the vertical axis can be formed on the upper edge and a complementary angle 136 measuring about 135 degrees relative to the vertical axis can be formed on the lower edge. In some embodiments, the vertical axis can be the vertical axis of the integrated fiber cement and foam panel when the integrated fiber cement and foam panel is positioned or assembled on a building structure. In some other embodiments, the angles 134 , 136 can be 0 to 90 degrees, 90 degrees to 180 degrees, 0 to 45 degrees, 45 degrees to 90 degrees, 90 degrees to 135 degrees.
In the embodiment shown in FIG. 3B , side 138 can have a range between 3.5 inches (8.9 cm) to 11 inches (27.9 cm), side 139 can have a range between 3.5 inches to 11 inches (8.9 cm to 27.9 cm), side 140 can have a range between 0.0625 inch to 0.375 inch (0.159 cm to 0.95 cm), side 141 can have a range between 0.25 inch to 1.25 inches (0.625 cm to 3.175 cm), side 142 can have a range between 0.0625 inch to 0.375 inch (0.159 cm to 0.95 cm), side 143 can have a range between 0.0625 inch to 0.375 inch (0.159 cm to 0.375 cm), and side 144 can have a range between 0.75 inch to 1.75 inch (1.91 cm to 4.45 cm). Angle 145 can have a range between 30 degrees to 60 degrees, angle 146 can have a range between 30 degrees to 60 degrees, and angle 147 can have a range between 1.5 degrees to 5.0 degrees.
In the embodiment shown in FIG. 3C , side 148 can have a range between 3.5 inches to 11 inches (8.9 cm to 27.9 cm), side 149 can have a range between 3.5 inches to 11 inches (8.9 cm to 27.9 cm), side 150 can have a range between 0.0625 inches to 0.375 inches (0.159 cm to 0.95 cm), side 151 can have a range between 0.625 inches to 1.75 inches (1.59 cm to 4.45 cm), and side 152 can have a range between 0.25 inches to 1.25 inches (0.625 cm to 3.175 cm). Angle 153 can have a range between 30° to 60°, angle 154 can have a range between 30° to 60°, and angle 155 can have a range between 1.5° to 5.0°.
In the embodiment shown in FIG. 3D , side 156 can have a range between 3.5 inches to 11 inches (8.9 cm to 27.9 cm), side 167 can have a range between 3.5 inches to 11 inches (8.9 cm to 27.9 cm), side 158 can have a range between 0.25 inches to 1.25 inches (0.635 cm to 3.175 cm), and side 159 can have a range between 0.625 inches and 1.75 inches (1.59 cm to 4.45 cm). Angle 160 can have a range between 30° to 60°, angle 161 can have a range between 30° to 60°, and angle 162 can have a range between 1.5° to 5.0°.
FIGS. 3E-3I depict additional profiles of foam layers that can be part of the integrated fiber cement foam and insulation panel.
FIGS. 3J-3N depict profiles of foam starter strips that can be placed at the bottom of a wall to start the proper kick out angle for installation of siding going up a wall.
In the embodiment shown in FIG. 3J , side 163 can have a range between 1.0 inches to 1.5 inches (2.54 cm to 3.81 cm), side 164 can have a range between 0.0625 inches to 1.0 inches (0.16 cm to 2.54 cm), and side 165 can have a range between 0.5 inches to 1.5 inches (1.27 cm to 3.81 cm). Angle 166 can have a range between 30° to 60° and angle 167 can have a range between 1.5° to 5.0°.
In the embodiment shown in FIG. 3K , side 168 can have a range between 1.0 inches to 1.5 inches (2.54 cm to 3.81 cm), side 169 can have a range between 0.0625 inches to 1.0 inches, (0.159 cm to 2.54 cm) and side 170 can have a range between 0.5 inches to 1.5 inches (1.27 cm to 3.81 cm). Angle 171 can have a range between 30° to 60° and angle 172 can have a range between 1.5° to 5.0°.
In the embodiment shown in FIG. 3L , side 173 can have a range between 1.0 inches to 1.5 inches (0.159 cm to 2.54 cm), side 174 can have a range between 0.0625 inches to 1.0 inches (0.159 cm to 2.54 cm), and side 175 can have a range between 0.5 inches to 1.5 inches (1.27 cm to 3.81 cm). Angle 176 can have a range between 30° to 60° and angle 177 can have a range between 1.5° to 5.0°.
In various embodiments, the fiber cement and foam insulation panels disclosed herein are designed with innovative water management mechanisms to facilitate ventilation and drainage of water and other liquids from the wall cavity. With reference to FIGS. 4A-4D , in various embodiments, the drainage channels may take on a variety of patterns including grooves, designs or logos 113 . As depicted in the illustrated embodiments, the drainage channel patterns are formed on the back side of the foam layer 104 . However, it should be appreciated that in various embodiments, the drainage channels 112 and grooves, designs or logos 113 may be formed along any surface of the foam, or in other embodiments, through the thickness of the foam. The drainage channels, can be made by machining or hot wire cutting or a spindle molder with aluminum blades. The channels or features may also be formed using molding techniques such as injection molding. In alternative embodiments, the drainage channels 112 can take the form of an embossed or debossed feature in the form such as an image, symbol, design or logo. In another embodiment, the drainage channels can take the form of chevrons or tread designs. In some embodiments wherein thermoplastic foams, such as polystyrene foams, are used, the drainage channels 112 may be added by machining using a router or grinder or by using a hot wire, water jet cutting or laser cutting means. In the case of thermosetting foams, water channel routing, grinding, or injection molding techniques may be preferred. In yet other embodiments, such as foams made out of expanded polystyrene (EPS), the drainage channels may be incorporated into the mold used to form the foam. In other embodiments, such as foams made out of cut block EPS foam, the porosity of the foam can function as the drainage channels or to improve ventilation. In such embodiments, the foam porosity can be adjusted to allow drainage. As such, the foam according to some embodiments of the present disclosure may not require drainage channels.
FIG. 5 illustrates an integrated wall assembly 300 according to one embodiment of the present disclosure. The wall assembly 300 can include a sheathing 301 , such as oriented strand board (OSB), and a plurality of prefabricated fiber cement and foam insulation panels 300 a-e mounted to the sheathing 301 . The foam layer 304 on each panel interlocks with the foam layer on adjacent panels such that the fiber cement layers 302 are aligned in a nested configuration. In the embodiment shown in FIG. 5 , water draining channels 312 are formed on the front surface of the foam layer. In some embodiments, the drainage channels 312 can be formed on the back surface of the foam layer 304 , within the interior foam layer, or a combination of the front, back surface and/or interior of the foam layer. In other embodiments, the drainage channels may be formed on the back face of the fiber cement layer 302 . In yet other embodiments, the drainage channels may be formed in both the foam layer and the fiber cement layers. In some implementations, a layer of weather resistant barrier material 313 , such as those marketed under the HardieWrap® brand, can be positioned between the sheathing 301 and the foam layer 304 of the fiber cement and foam insulation panel 300 a - 300 e.
FIG. 6A illustrates an embodiment of a fiber cement and foam insulation trim corner 400 with an integrated fastening tab 416 . The trim corner 400 with the fastening tab 416 is for use around an outside corner of a building structure. FIG. 6B illustrates an embodiment of a foam insulation panel with an integrated fastening tab for use around an inside corner of a building structure. The fastening tabs 416 are configured for mounting the fiber cement and foam insulation trim corner to the building frame or other support structure without having to attach a fastener through the front face of the fiber cement layer 402 . As such, the fastening tabs 416 can be used so that the fasteners are concealed from view upon installation of the panels. The panels 400 may also be useful in installations where the wall does not include a sheathing to attach the panels. As shown in the illustrated embodiments in FIGS. 6A-6B , in some embodiments, the fastening tabs 416 can have one or more overhanging portions 417 extending outwardly from an edge of the foam layer to fasten to a support structure of a building (e.g., extending from the lateral edges of the foam layer). In one preferred embodiment, the overhanging portions 417 can be between 3-10 inches (7.62 cm-25.4 cm) in length, more preferably approximately 3 inches (7.62 cm) in length.
As shown in FIG. 6A and FIG. 6C , in some embodiments, the fastening tabs 416 can be arranged to be disposed between the fiber cement layer 402 and the foam layer 404 . In some embodiments, the fastening tab 416 is generally formed of a strip of metal shaped to follow the contours of the exterior or interior surface of the foam layer 404 .
With reference to FIGS. 6A-6B , and FIGS. 6D-6F in some embodiments, the fastening tabs 416 can have a one or more recesses or flat tangs or flanges 419 creating a notched or angled profile. The recesses 419 can allow the overhanging portions 417 to be flush with a surface of the foam and/or flush with mating components of the building to fasten to a support structure of the building. Preferably, the recesses 419 are between 0.25″ and 1″ in length. The fastening tabs can be installed in a manner such that at least a portion of each fastening tab is concealed from view when the wall panel 400 is installed on the building. The fastening tabs 416 can include angled or filleted corners 478 with radii between 1/32″ and 1/16″.
FIGS. 6D-6F illustrate embodiments of fastening tab 416 profiles.
FIG. 6D illustrates an embodiment of a fastening tab 416 profile for use in a fiber cement and foam insulation board installed around an inside corner. In one implementation, portions 421 a , 421 b of the fastening tabs 416 adjacent the foam layer can be between 3″ to 11.5″ (7.62 cm to 29.21 cm) ( 421 a ) and/or between 4″ to 11.5″ (10.16 cm to 29.21 cm) ( 421 b ), the overhanging portions 417 can be between 3″ to 10″ (7.62 cm to 25.4 cm), preferably 3″ (7.62 cm), the recesses 419 can be between 0.25″ (0.625 cm) and 1″ (2.54 cm), and the edges 478 can have radii between 1/32 (0.079 cm) and 1/16 (0.159 cm), as depicted in FIG. 6D . Such an embodiment can be used for inside corner installations.
FIG. 6E illustrates an embodiment of a fastening tab 416 profile for use in a fiber cement and foam insulation board installed around an outside corner. In one implementation, portions 421 a , 421 b of the fastening tabs 416 adjacent the foam layer can be between 1.5″ to 10.5″ (3.81 to 26.67 cm) ( 421 a ) and/or between 2″ to 11″ (5.08 cm to 27.94 cm) ( 421 b ), the overhanging portions 417 can be between 3″ to 10″ (7.62 cm to 25.4 cm), preferably 3″ (7.62 cm), the recesses 419 can be between 0.25″ (0.625 cm) and 1″ (2.54 cm), and the edges 478 can have radii between 1/32 (0.079 cm) and 1/16 (0.159 cm), as depicted in FIG. 6E . Such an embodiment can be used for inside corner installations.
FIG. 6F illustrates another embodiment of a fastening tab 416 profile for use in an integrated fiber cement and foam insulation panel. In one implementation, portions 421 of the fastening tabs 416 adjacent the foam layer can be between 3″ to 10″ (7.62 cm to 25.4 cm), the overhanging portions 417 can be between 3″ to 10″ (7.62 cm to 25.4 cm), preferably 3″ (7.62 cm), the recesses 419 can be between 0.25″ (0.625 cm) and 1″ (2.54 cm), and the edges 478 can have radii between 1/32 (0.079 cm) and 1/16 (0.159 cm) as depicted in FIG. 6F . Such an embodiment can be used for non-corner installations. It should be appreciated that in other embodiments, the length of the portion 421 of the fastening tabs 416 adjacent the foam layer can be sized to any dimensions necessary to match the foam layer length. In one embodiment, the overall thickness of the fastening tab 416 is between 16 to 20 gauge, preferably 18 gauge.
FIGS. 6G-6I illustrate embodiments of foam profiles for use with fastening tabs in fiber cement and foam insulation panels.
FIG. 6G illustrates an embodiment of a foam profile for use in an inside corner section of an integrated fiber cement and foam insulation panel with integrated fastening tabs. In such an embodiment, the foam layer 404 can have an “L” shape configuration and can have a side length 479 between 3.5″ to 14″ (8.89 cm to 35.56 cm) and a side length 480 between 3.5″ to 13″ (8.89 cm to 33.02 cm), with thicknesses 481 , 482 between 0.25″ to 1.5″ (0.625 cm to 3.81 cm).
FIG. 6H illustrates an embodiment of a foam profile for use in an outside corner section of a fiber cement and foam insulation panel with integrated fastening tabs. In such an embodiment, the foam layer 404 can have an “L” shape configuration and can have a side length 483 between 3.5″ to 14″ (8.89 cm to 35.56 cm) and a side length 484 between 1.5″ to 10.5″ (3.81 cm to 26.67 cm) with thicknesses 485 , 486 between 0.25″ to 1.5″ (0.625 cm to 3.81 cm).
FIG. 6I illustrates an embodiment of a foam profile for use in a fiber cement and foam insulation panel with integrated fastening tabs. In such an embodiment, the foam layer 404 can have a length 488 between 1.5″ to 12″ (3.81 cm to 30.48 cm) with a thickness 487 between 0.25″ to 1.5″ (0.625 cm to 3.81 cm).
In some embodiments, the fastening tabs 416 can be attached to the panel 400 using one or more connecting elements. The connecting elements can include nails, staples, pins, rivets, screws, anchors, clasps, bolts, bucklers, clips, snaps, and other types of fasteners as in known to those of skill in the art. In yet further embodiments, the foam layer can include one or more recess features (not illustrated) in which the tabs are placed such that the tabs do not extend beyond the back wall of the foam layer. In some embodiments, the recess feature in the foam layer may be formed using the same techniques as for forming drainage channels and/or interlocking features in a separate step. In addition, the recess features may be formed out of a mold specifically designed to yield a foam layer having drainage channels, interlocking features, and recess features. In further embodiments, the fastening tabs 416 can attach the panel 400 to the support structure using at least one connecting element described above.
FIG. 7 illustrates yet another embodiment of the present disclosure showing a prefabricated panel 600 including a fiber cement layer 602 , a backing 622 and a foam layer 604 disposed therebetween connecting the backing 622 to the fiber cement layer 602 . In some embodiments, the backing 622 preferably made out of OSB and can be laminated to the foam layer 604 . It will be appreciated that the foam layer 604 and/or the fiber cement layer 602 can incorporate various interlocking features to facilitate alignment and sealing of the adjacent layers and drainage channels to facilitate water management.
FIG. 8 illustrates yet another embodiment of the present disclosure showing an integrated fiber cement and foam insulation panel 700 incorporating a discontinuous layer 724 in the foam layer 704 a , 704 b . The discontinuous layer 724 can provide enhanced acoustic dampening properties, reducing unwanted outside noise and vibrations from entering the building and also reducing interior noises from leaving the building. Such an embodiment can act to give further privacy for occupants inside of the building. In some implementations, the discontinuous layer 724 can be made of a viscoelastic material. Preferably, the discontinuous layer 724 is attached to framing members of the wall to dampen vibrations from the exterior of the building from being transmitted to the interior of the building.
FIG. 9 illustrates a further embodiment of the present disclosure showing a prefabricated fiber cement and foam insulation panel 800 designed for high shear applications. The panel 800 includes a fiber cement layer 802 , a foam layer 804 , and a mesh 826 disposed therebetween for reinforcement. In some embodiments, the panel 800 can provide sufficient shear strength to eliminate or substantially reduce the need for structural sheathing, such as OSB. In other embodiments, the foam layers may include facing materials such as meshes or non woven sheets to enhance the shear strength of the fiber cement and foam insulation panel 800 . In yet further embodiments, the panel 800 may also incorporate mesh or reinforcing fibers within the body of the foam layer. The panel may include vapor permeable facing materials adjacent the foam layer, including foils or films to reflect heat or heat loss due to air permeability.
FIGS. 10A-10C illustrate further embodiments of the present disclosure showing two fiber cement and foam insulation panels 900 a , 900 b joined together with a butt joint 926 . The panels include fiber cement layers 902 a , 902 b and profiled foam layers 904 a , 904 b . In this embodiment, the profiled foam layers 904 a , 904 b extend only a partial length of each respective fiber cement layer 902 a , 902 b , thus leaving a space on both ends of each fiber cement layer configured to receive an insert 928 . The insert 928 can be placed at the joint 926 to mitigate water penetration into the wall and allow condensation to drip over the face of the plank below the lap siding. The insert 928 can include a foam layer 932 laminated with a piece of house wrap or flashing 930 . The flashing 930 may be used as a water resistive barrier. The flashing 930 can be constructed to be longer than the foam layer 932 such that when joined together to form the insert 928 , the flashing includes an overhang 931 which extends beyond a length of the foam layer 93 (best depicted in FIG. 10B ). In one preferred embodiment, the foam layer 932 of the insert 928 can have a nominal width of 6 inches (15.24 cm) and the flashing 930 can have an overhang 931 of approximately 1.16 inches (2.95 cm). In one embodiment, the insert 928 can include a foam layer 932 having a profile that matches the profile of the mating foam layers 904 a , 904 b of the adjacent panels 900 a , 900 b.
FIGS. 11A and 11B are schematic illustrations of certain connection mechanism that can be used to join adjacent integrated fiber cement and foam panels 1100 a , 1100 b at a butt joint. In one embodiment, a recess 1101 a , 1101 b is formed along the lateral edges of each panel 1100 a , 1100 b . Each recess is configured to receive a portion of an insert 1102 a , 1102 b designed to join the two panels. The insert 1102 a , 1102 b can assume a variety of different shapes and configurations. In one embodiment, the insert 1102 b is an elongate planar member that can be made out of foam, fiber cement, or other material. The insert 1102 b can be inserted between the two panels and slidingly engage with the recesses formed on the edge of each panel. In some embodiments, the insert 1102 a is keyed to mate with corresponding patterns in the recess 1101 a , 1101 b so as to interlock and further secure the two panels.
FIG. 12 depicts a flow diagram of installation 1000 of fiber cement and foam insulation panels on a wall according to one embodiment. The method includes cutting and trimming 1002 starter strips. As described above, starter strips can be used to ensure a consistent plank angle for the integrated panels. The method next includes installing 1004 the starter strips at the base of the wall. Starter strips may be fastened to the wall using one or more fasteners described above (e.g. siding nails from 6 d to 16 d ). The starter strips may be fastened to a sheathing (when present) or directly to the studs of the building. The method further includes cutting and trimming 1006 the integrated fiber cement and foam insulation panels. The method next includes installing 1008 the fiber cement and foam insulation panels to the wall. In some embodiments, as described above, the panels can include interlocking features for nesting or crotchedly connecting the panels. In some embodiments, as described with reference to FIGS. 6A-61 , panels incorporating fastening tabs can be used. As described above, fastening tabs may be useful in installations where the wall does not include a sheathing to attach the panels to conceal the fasteners. The method optionally includes installing 1010 inserts at the butt joints between adjacent panels, as described with reference to FIGS. 10A-10C and 11 A- 11 B. As described above, the inserts can include a flashing to act as a water resistive barrier.
FIG. 13 illustrates yet another embodiment of an integrated fiber cement and foam insulation panel 1300 . The panel 1300 generally includes two fiber cement layers 1302 a , 1302 b and a profiled foam layer 1304 disposed therebetween. The fiber cement layers 1302 a , 1302 b can be attached to opposing faces of the foam layer 1304 via a suitable adhesive. As shown in FIG. 13 , the thickness of the foam layer 1304 can be substantially greater than the thickness of the fiber cement layers 1302 . In some embodiments, the foam layer 1304 includes profiled edges configured to mate and interlock with corresponding edges on adjacent panels, thereby forming a continuous surface. The panel 1300 is preferably pre-fabricated so that it can be used readily at the construction site.
The advantages of the prefabricated integrated fiber cement and foam composite insulation panel include a higher R-value fiber cement building material that is easily installed, provides a building envelope that resists penetration from the elements yet can breath and drain water away from the interior, and a faster installation time when a builder decides to use foam insulation on the structure.
To avoid over-compression and distortion when attaching the integrated fiber cement and foam panels to a wall, the foam preferably has a minimum compressive strength of about 15 psi as determined by ASTM D 6817. In some embodiments, to ensure that the integrated fiber cement and foam system has a minimum wind load resistance of 3.0 kPa ultimate load when tested using an ASTM E 330 vacuum testing apparatus, the minimum compressive strength of the foam is preferably about 15 psi as determined by ASTM 6817. In one embodiment, an integrated fiber cement and foam insulation cladding panel, formed in accordance with the designs disclosed herein, has a wind load of greater than 83 psf, preferably greater than or equal to 94 psf.
The foregoing description of the preferred embodiments of the present disclosure has shown, described and pointed out the fundamental novel features of the inventions. The various devices, methods, procedures, and techniques described above provide a number of ways to carry out the described embodiments and arrangements. Of course, it is to be understood that not necessarily all features, objectives or advantages described are required and/or achieved in accordance with any particular embodiment described herein. Also, although the invention has been disclosed in the context of certain embodiments, arrangements and examples, it will be understood by those skilled in the art that the invention extends beyond the specifically disclosed embodiments to other alternative embodiments, combinations, sub-combinations and/or uses and obvious modifications and equivalents thereof. Accordingly, the invention is not intended to be limited by the specific disclosures of the embodiments herein. | An integrated fiber cement and foam cladding system is provided that incorporates foam or similar light weight material to improve the insulation capacity of the cladding system. The system includes at least a fiber cement layer and a foam layer disposed on the backside of the fiber cement layer. The system improves the R-value of the building, a measure of the building's resistance to transferring heat or thermal energy. | 4 |
FIELD OF THE INVENTION
This invention relates generally to the analogue measurement of alignment between layers of a semiconductor device and, more particularly, to a method of determining a critical distance or allowable margin between layers of a semiconductor device by means of an analogue measurement performed in respect of a test structure, and a test structure for use in such a method.
BACKGROUND OF THE INVENTION
Modern integrated circuits are typically fabricated in multiple layers on a semiconductor (e.g. Silicon) wafer. During fabrication of an integrated circuit die, lithographic processes are widely used to lay down successive circuit layers that together define electronic devices on the integrated circuit die. During the fabrication process, a different mask is used to pattern each layer. Misalignment between successive layers of the integrated circuit die, which is caused by misalignment between the masks that define the various device layers, is present in substantially all integrated circuit dies to some degree. There is, however, a tolerable amount of misalignment that may exist in any given integrated circuit die before operation of the integrated circuit die is jeopardized.
In semiconductor manufacturing, the overlay between lithographically defined layers becomes more critical as lateral dimensions shrink in current and future technology nodes. In the 65 nm CMOS technology node, for example, poly-to-contact (poly stands for poly-Silicon which is the gate material) overlay becomes one of the most critical parameters for yield.
Referring to FIG. 1 of the drawings, there is provided a schematic cross-sectional view of a portion of an integrated circuit die configuration which is particularly sensitive to poly-to-contact short circuits due to misalignment of the respective layers of the integrated circuit die. The structure comprises a semiconductor substrate 100 typically of mono-crystalline Silicon, in which at least one isolation means 101 , such as “shallow trench isolation” or STI, is formed to electrically separate, for example, n-type regions (not shown) and p-type regions (not shown) in a CMOS device, such regions being formed in the substrate 100 by, for example, conventional dopant diffusion or implantation. An active device 102 in the form of, for example, an NMOS or PMOS transistor is provided on the substrate 100 , which device comprises a gate electrode structure 103 (formed by, for example, a conventional gate and spacer etching process) with a layer of poly-Silicon gate material 104 . Conventional Metal-Oxide Semiconductor Field-Effect Transistors (MOSFETs) utilize poly-Silicon for forming gate electrodes, in view of its good thermal stability. In addition, poly-Silicon-based materials advantageously block implantation of dopant ions into the underlying channel region of the transistor, thereby facilitating the formation of self-aligned source and drain regions after gate electrode deposition/patterning is completed.
An integrated circuit is typically fabricated by etching trenches in a semiconductor substrate, in patterns defined by a photo-mask, then filling these trenches by an isolating material to realize electrically isolated active areas. Ion implantation is used to dope these areas as n-type or p-type. The active areas are then oxidized, after which step a gate material is deposited. A subsequent photolithography and anisotropic etching step is used to selectively remove gate material in order to construct, amongst other devices, field-effect transistors. Masked ion implantation steps are performed to highly dope the gate patterns and those active areas which are not covered by gate patterns, after which the formed transistors as well as other active and passive devices are interconnected as required, through respective contacts, by interconnection lines. Accordingly, in the structure illustrated in FIG. 1 of the drawings, the active device 102 is connected to the metal interconnecting line 105 by means of a contact 106 extending from the surface of the substrate 100 .
In the exemplary structure shown, there is a critical distance d between the gate material 104 and the contact 106 . Since the gate material and contact regions are patterned in separate lithographic steps, poly-to-contact shorts can be caused by misalignment between the respective patterns (which causes the distance between the gate material 104 and the contact 106 to be less than the critical distance), in addition to variation of the lateral dimensions of the gate 104 and contact 106 .
For the 65 nm technology node, the minimal design rule for poly-to-contact distance d is very close to the accuracy capability of conventional lithographic tools and it is therefore imperative to have an adequate quantification of the distance between poly and respective contacts (and/or other critical electrical distances, such as, via-to-metal) in order to properly control the process and have a good diagnosis capability if an issue should arise. This quantification should ideally be possible in an early stage of the fabrication process (parametric test) and have acceptable process overheads in terms of measurement cost and time.
In one known method, during process development, a set of parametric test structures is used in which the poly-to-contact distance is systematically varied. The resultant test structures are placed on development reticules, which have a large fraction of their surface dedicated to engineering purposes, and measurements are performed on an individual basis in respect of the test structures to create a set of parametric test data defining the acceptable margin of variation in the critical distance. This is an expensive approach in terms of time and Silicon area, and as a result tends not to be used in production.
Other known methods describe the combination of poly-contact distance variations in a single “vernier” test structure combined with a digital test. It will be appreciated by a person skilled in the art that a vernier test structure is based on a well-known precision measurement method using interference patterns. In this approach, a large number of measurements, performed on digital remain measurement equipment, is necessary to determine the actual overlay margin; however, due to the requirement for digital measurement equipment, which is incompatible with parametric test equipment, such structures also are not generally used in production.
U.S. Pat. No. 6,221,681 relates to on-chip misalignment indication using misalignment circuit indicators fabricated in layers of an integrated circuit die wherein a current between two contacts varies as resistance between the contacts varies as a function of misalignment. Experimentation with varying degrees of misalignment results in a determination of a maximum and minimum amount of current between the contacts at a given voltage. The maximum and minimum amounts of current correspond to maximum misalignments in one and the other directions along the coordinate axis. Thus, the maximum and minimum amounts of current define an acceptable range of misalignment between successive layers. If the amount of current between the two contacts is either greater than the maximum amount of current or less than the minimum amount of current for a given voltage applied between the two contacts, misalignment between successive layers is considered to be out of tolerance, and the integrated circuit die is considered to have failed misalignment testing. In the described arrangement, there is provided a plurality of on-chip misalignment circuit indicators, each comprising a first conductor connecting a first contact region to a first pad and a second conductor connecting a second contact region to a second pad. The on-chip misalignment indicators may comprise any type of appropriate semiconductor device in which the current path through the device varies dependent upon the length, and hence the resistance, between locations in the device. Current measurements need to be performed in respect of each on-chip misalignment indicator, and at least one but more preferably a set of misalignment indicators are provided to detect misalignment along each respective coordinate axis of the integrated circuit die.
However, in addition to the fact that the arrangement described in U.S. Pat. No. 6,221,681 is concerned with the occurrence of unintentionally high resistance between layers of the device which are intended to be contacted, it is focused on separately tested test structures, i.e. it works with multiple measurements, one for each overlay variant, which is costly, particularly in terms of time.
SUMMARY OF THE INVENTION
On the contrary, the present invention is primarily concerned with the determination of the probability or likelihood of unintentional shorts between layers not intended to be in contact with each other, and it is an object of the present invention to provide a more cost-effective method of obtaining parametric test data in respect of a semiconductor device structure, and thereby quantifying misalignment of successively deposited layers of a semiconductor device. It is also an object of the present invention to provide a test structure for use in the above-mentioned method, a method of fabricating such a test structure, a method and apparatus for testing a semiconductor device structure using the parametric test data obtained by means of the above-mentioned method, a method of fabricating an integrated circuit including one or more semiconductor device structures tested using the parametric test data obtained by means of the above-mentioned method, and an integrated circuit die fabricated by such a method.
In accordance with the present invention, there is provided a method of obtaining parametric test data for use in monitoring alignment of first and second layers of material successively deposited on a substrate defining two respective non-contacting component types on an integrated circuit die, the method comprising providing a test structure comprising a conductive first line, a second line of the material of said first layer of material, and a plurality of component regions, each component region comprising one or more components defined by said second layer of material and being provided on said conductive first line relative to said second line of material, wherein a first component region is located at a first distance from said second line of material and a second component region is located in contact with said second line of material, said second line of material defining a resistance between said first and second component regions, the method further comprising performing a single analogue measurement between said conductive first line and said second line of material so as to measure the resistance therebetween, said resistance being indicative of a probability of a short circuit occurring between said first and second layers of material depending upon the distance therebetween.
Also in accordance with the present invention, there is provided a test structure for use in the above-mentioned method, the test structure comprising a conductive first line, a second line of the material of said first layer of material, and a plurality of component regions, each component region comprising one or more components defined by said second layer of material and being provided on said conductive first line relative to said second line of material, wherein a first component region is located at a first distance from said second line of material and a second component region is located in contact with said second line of material, said second line of material defining a resistance between said first and second component regions, the test structure further comprising means for enabling a single analogue measurement to be performed between said conductive first line and said second line of material so as to measure the resistance therebetween.
The present invention also extends to an analogue signal including parametric test data obtained by means of the above-mentioned method, and to the use of parametric test data obtained by means of the above-mentioned method in monitoring alignment of a first and second deposited layers of a semiconductor device structure.
The present invention extends still further to a method of, and apparatus for, monitoring alignment of first and second deposited layers of a semiconductor device structure using the parametric data obtained by means of the above-mentioned method, and further still to a method of fabricating an integrated circuit die comprising a plurality of semiconductor device structures, the method including monitoring alignment of first and second deposited layers of one or more of the semiconductor device structures using parametric data obtained using the above-mentioned method, and an integrated circuit die manufactured according to such a method.
Thus, the present invention provides an approach to misalignment quantification, in which only a single analogue measurement is required to be performed in order to obtain a misalignment margin in respect of two, separately deposited layers of material of a semiconductor device, which layers are not intended to be in contact with each other, based on the analogue response of the test structure, so as to provide an indication of the probability of the occurrence of shorts (caused by excessive misalignment of the layers) in semiconductor device structures by testing thereof during manufacture. In other words, the parametric test data referred to above preferably comprises a critical distance in respect of the space between said first and second layers and/or an acceptable margin in respect of said critical distance based on the measured resistance of the second line of material at a given voltage.
In a preferred embodiment, one or more third component regions are located between said first and second component regions, said one or more third component regions being located at a distance from said second line of material which is less than said first distance. In one exemplary embodiment, two or more third component regions are located between said first and second component regions at successively smaller distances from said second line of material.
Beneficially, the resistance of said second line of material between the or each pair of component regions is at least of the order of the resistance of a short circuit between said first and second layers of material. As a result, the actual resistance of such a short circuit becomes relatively insignificant, such that the number of “high-resistance units” can be measured in a single analogue measurement. Preferably, the resistance of the second line of material is dependent upon the respective length of the second line of material.
The second line of material is preferably provided in a meandering configuration, having two or more elongate portions, which are preferably substantially parallel, with respective connecting portions therebetween, wherein at least one component region is preferably provided in respect of each elongate portion. The elongate portions are preferably transverse to the conductive first line of material, and preferably substantially perpendicular thereto. Each component region may comprise a row of respective components located relative to a respective elongate portion of said second line of material substantially parallel thereto. In one exemplary embodiment, two component regions are provided in respect of each elongate portion of said second line of material, one on each side thereof. This enables positive and negative misalignment to be measured at the same time.
Preferably, said single analogue measurement may be obtained between a first end of said second line of material and said conductive first line of material, additional measurements may be obtained between said first end and a second end of said second line of material to determine the total resistance of said second line of material. In addition, or alternatively, measurements may be obtained in respect of the individual resistances of selected portions, e.g. said elongate portions (by means of, for example, digital “tap off” fingers), of said second line of material, so as to enable the test structure to be calibrated.
In one exemplary embodiment, the method may be used in obtaining parametric data for monitoring alignment of a layer of gate material and a contact layer (i.e. poly-contact alignment). In another exemplary embodiment, the method may be used in obtaining parametric data for monitoring alignment of a metal layer and a via (i.e. metal-via alignment). In yet another exemplary embodiment, the method and test structure can be used for LIL (local interconnect realized in tungsten or other conducting material)-to-poly overlay.
These and other aspects of the present invention will be apparent from, and elucidated with reference to, the embodiments described herein.
BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments of the present invention will now be described by way of examples only and with reference to the accompanying drawings, in which:
FIG. 1 is a schematic cross-sectional illustration of a semiconductor device structure which is sensitive to poly-to-contact shorts;
FIG. 2 is a schematic plan view of an electrical test structure according to a first exemplary embodiment of the present invention for use in measuring poly-to-contact alignment;
FIG. 3 is a schematic circuit diagram illustrating the electrical connectivity of the structure of FIG. 2 ;
FIG. 4 a is a schematic cross-sectional illustration of a device structure which is sensitive to via-to-bottom metal shorts;
FIG. 4 b is a schematic cross-sectional illustration of a device structure which is sensitive to via-to-top metal shorts;
FIG. 5 is a schematic plan view of an electrical test structure according to a second exemplary embodiment of the present invention for use in measuring via-to-metal alignment;
FIG. 6 is a schematic plan view of an electrical test structure according to a third exemplary embodiment of the present invention for use in measuring poly-to-contact alignment; and
FIG. 7 is a schematic plan view of an electrical test structure according to a fourth exemplary embodiment of the present invention for use in measuring poly-to-contact alignment.
DETAILED DESCRIPTION OF THE INVENTION
As it has been established above, good process monitoring capability is critical to the success of any state-of-the-art semiconductor fabrication process. Data is needed to control equipment variability, and to understand process limitations which influence design rules. However, as explained above, because of shrinking feature sizes and decreasing tolerances, adequate process monitoring is becoming increasingly difficult. It has been found that automated optical alignment measurements are frequently insufficient to guarantee a sufficient degree of electrical isolation between misaligned layers. One known arrangement comprising on-chip misalignment circuit indicators is described above in relation to U.S. Pat. No. 6,221,681. Another type of electrical test structure is proposed by G. Freeman, W. Lukaszek, T. W. Ekstedt and D. W. Peters, “Experimental verification of a novel electrical test structure for measuring contact size”, IEEE Trans. Semic. Manuf., vol. 2, No. 1, February 1989, pp. 9-15, which is shown therein to be capable for use in measuring contact size. It is, however, also suitable for measuring, among other parameters, alignment. The structure proposed in the above-mentioned document is based on the concept of a digital vernier, and comprises a strip of poly-Silicon flanked on its two sides by rows of contacts, with each contact slightly offset from the one next to it. Two types of measurements are then made on this structure to determine contact size. The first is a continuity measurement between each contact and the poly strip. This determines which contacts on each side touch the poly and which do not. From this information, it is possible to determine where the edge of the poly lies relative to the contact edges. The second measurement is of the poly line-width. These two measurements can then be used to give the contact size.
The following exemplary embodiment of the present invention effectively modifies the “vernier” layout of the test structure proposed in the above-mentioned reference to transform the digital overlay measurements into a single analogue measurement. Referring to FIG. 2 of the drawings, in the proposed structure according to a first exemplary embodiment of the present invention, a poly-Silicon line 10 of relatively narrow width is used, which is deposited on a semiconductor substrate in a meandering configuration, comprising a plurality of substantially parallel, substantially horizontal regions 12 and a plurality of connecting portions 14 , between a first end A and a second end B.
With respect to each horizontal region 12 of the poly line 10 , a set of contacts 16 is provided, the contact sets being placed at different distances relative to respective horizontal regions 12 , as shown. It will be appreciated that the contacts 16 extend from the semiconductor substrate (not shown) to a relatively wide, conductive (metal-1) line 18 . In the exemplary embodiment illustrated in FIG. 2 , the distance between each contact set and the respective horizontal region 12 of the poly line 10 decreases sequentially and, in one embodiment, it may decrease sequentially from a first distance significantly greater than the critical poly-to-contact distance to the critical distance, which critical distance is the minimum poly-to-contact distance permitted before the likelihood of the occurrence of a poly-to-contact short is greater than some design minimum. Alternatively, the distance between each contact set and the poly line 10 may decrease in steps of one design grid, starting at a distance which is slightly relaxed with respect to a minimum design rule (i.e. greater than the above-mentioned critical distance), and ending at a zero nominal distance or even a slight overlap of the contact 16 on the poly 10 , as shown in FIG. 2 . The electrical connectivity of the proposed test structure illustrated in FIG. 2 , is illustrated schematically in FIG. 3 of the drawings, which illustrates more clearly that a poly-to-contact short is introduced only in respect of contact group 16 d , although the distance between contact group 16 c and the poly line (or “meander”) 10 is also less than the critical distance, such that the probability of a poly-to-contact short is relatively high.
By way of example only, an exemplary test structure might typically be produced as follows:
First step: realize the meander, for instance in poly, by depositing a layer of poly-crystalline Silicon, photolithographically defining the desired pattern, then etching away everything except the meander.
Second step: deposition of an electrically isolating and planarizing layer (often called “interlevel dielectric”).
Third step: realize contacts by etching photolithographically defined holes in the isolating layer, then by filling these with a conductive material such as tungsten. (It is the overlay between these contacts and the poly meander that the test structure is intended to quantify).
Fourth step: realize the conductive line ( 18 ) in metal-1. In older CMOS technologies, this would be done by depositing Al—Cu, photolithographically masking the area which is to become the wide line, and etching away all other metal. In more recent technology nodes, this may be realized by depositing a second electrically isolating layer, etching a slit in this layer which is so deep as to expose the contacts, and to fill the slit by Copper Cu.
In contrast with prior art test structures, an intentionally significant resistance is introduced between the contact groups 16 a - d (i.e. between potential points of poly-contact shorts) by, for example, a relatively long length of poly 10 . This resistance is of the order of, or greater than, the potential poly-contact short resistance. By doing this, the actual resistance of the poly-contact short becomes relatively unimportant. This permits measurement of the number of “high-resistance units” in a single analogue measurement which is sufficient to detect the probability of poly-contact shorts through misalignment.
In the exemplary embodiment illustrated in FIG. 2 of the drawings, a single measurement of the resistance between terminal A (first end of the poly meander 10 ) and terminal C (on the metal-1 line 18 ) is sufficient to estimate the length of poly until the first shorting contact group. In other words, a single measurement between terminals A and C is sufficient to determine the critical poly-to-contact distance. Thus, the poly-to-contact margin can be quantified immediately. Even if the poly-contact short resistance is much higher for a marginally shorting contact (e.g. 16 c ) than for a properly targeted “contact to poly” (e g. 16 d ), the analogue response of this test structure will depend in a continuous, uniformly increasing fashion on the poly-to-contact margin.
Thus, consider that the probability of a poly-to-contact short at the largest poly-contact distance provided on the test structure (which is known) is 0% and the probability of a poly-to-contact short at the targeted “contact to poly” is 100%, a uniform analogue function (defined by the poly meander resistance) is defined between the two, which effectively provides, in a single analogue measurement at a given voltage, the required parametric data to enable the critical poly-to-contact distance (or an acceptable margin in respect thereof) can be determined in respect of the integrated circuit die of interest; or, in other words, the degree of misalignment of (or the resultant effective distance between) the layers forming the poly region and the contact region respectively of the integrated circuit die can be thereby quantified in terms of a probability of a poly-to-contact short as a result thereof.
Terminal B can be used to measure the total meander resistance, but this additional measurement is not strictly necessary.
The fact that test structure described above requires a minimal number of pads and only one single measurement, makes it very cost effective for measuring poly-to-contact shorting issues. It will be appreciated that, although in the exemplary embodiment illustrated in FIG. 2 of the drawings, each contact set 16 a to d comprises 4 contacts 16 , a different number of contacts may be used in respect of each set, and the invention is not intended to be limited in any way in this regard.
The basic concept of the test structure of the invention can equally be used for via-to-metal overlay in device structures such as those shown in FIGS. 4 a and 4 b . FIG. 4 a illustrates a device structure comprising two parallel sets of metal lines, the first (or bottom) one being denoted by reference numeral 20 and the second (or top) one being denoted by reference numeral 22 , wherein corresponding top and bottom lines 20 , 22 are connected by a via 24 . As shown, metal-to-via shorts can occur between a bottom metal line 20 and the via 24 ( FIG. 4 a ) or between a top metal line 22 and the via 24 ( FIG. 4 b ), and d in FIGS. 4 a and 4 b denotes the via-to-metal short critical distance with respect to the bottom metal line 20 and the top metal line 22 , respectively.
Referring to FIG. 5 of the drawings, an electrical test structure according to an exemplary embodiment of the present invention for use in measuring via-to-metal alignment is analogous to that described with reference to FIG. 2 of the drawings for use in measuring poly-to-contact alignment. Thus, the structure comprises a metal line 30 of relatively narrow width in a meandering configuration (the length of which is adapted to account for the metal sheet resistivity), the metal line 30 comprising a plurality of substantially parallel, substantially horizontal regions 32 and a plurality of connecting portions 34 , between a first end A and a second end B.
With respect to each horizontal region 32 of the metal line 30 , a set of vias 36 is provided, the via sets being placed at different distances relative to respective horizontal regions 32 , as shown. It will be appreciated that the vias 36 are provided on a second, relatively wide metal line 38 . In the exemplary embodiment illustrated in FIG. 5 , the distance between each via set 36 a to 36 d and the respective horizontal region 32 of the metal line 30 decreases sequentially, as described with reference to the exemplary test structure described with reference to FIG. 2 of the drawings. As before, a single measurement of the resistance between terminal A (first end of the metal meander 30 ) and terminal C (on the second metal line 38 ) is sufficient to estimate the length of metal meander 30 until the first shorting via group. In other words, a single measurement between terminals A and C is sufficient to determine the critical via-to-metal distance d. Thus, the via-to-metal margin can be quantified immediately.
Referring to FIG. 6 of the drawings, a test structure according to a third exemplary embodiment of the present invention (for use in measuring poly-to-contact alignment in this case, but the same principle applies to an analogous test structure for measuring via-to-metal alignment) is similar in many respects to the test structure illustrated in FIG. 2 of the drawings, and like elements thereof are denoted by like reference numerals. However, in this case, a number of additional terminals 17 a , 17 b , 17 c , 17 d (or “fingers”) are provided, one in respect of each contact set 16 a , 16 b , 16 c , 16 d . These “fingers” can be used to measure individual resistances between respective contact sets and terminal A (i.e. terminal A to terminal D 1 , terminal A to terminal D 2 , etc.), which individual measurements can be used to calibrate the test structure.
Referring to FIG. 7 of the drawings, a test structure according to a fourth exemplary embodiment of the present invention (again for use in measuring poly-to-contact alignment in this case, but the same principle applies to an analogous test structure for measuring via-to-metal alignment) is similar in many respects to the test structure illustrated in FIG. 2 of the drawings, and like elements thereof are denoted by like reference numerals. However, in this case, two sets of contacts 16 are provided in respect of each horizontal region 12 of the poly meander 10 , one set on either side of each respective horizontal region 12 . This enables positive and negative misalignment to be measured at the same time. In this case, the width of the poly meander 10 may need to be adapted in order to allow for the minimum contact-to-contact distance as specified by the design rules (i.e. in the illustrated example, the poly 10 is wider in the portions neighboring the contacts).
It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be capable of designing many alternative embodiments without departing from the scope of the invention as defined by the appended claims. In the claims, any reference signs placed in parentheses shall not be construed as limiting the claims. The word “comprising” and “comprises”, and the like, does not exclude the presence of elements or steps other than those listed in any claim or the specification as a whole. The singular reference of an element does not exclude the plural reference of such elements and vice-versa. The invention may be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In a device claim enumerating several means, several of these means may be embodied by one and the same item of hardware. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. | A method of obtaining parametric test data for use in monitoring alignment between layers of a semiconductor device. The method employs a test structure comprising a meander ( 10, 30 ) of the material of a first layer of the semiconductor device, deposited relative to a conductive line ( 18,38 ). A number of sets ( 16 a, 16 b, 16 e, 16 d ) of components 16 , such as contacts or vias, are provided relative to the meander ( 10 ), at successively smaller distances therefrom. A single analogue measurement can be performed between a first and (A) of the meander ( 10, 30 ) and the conductive line ( 18, 38 ) so as to determine the resistance therebetween, and the critical distance at (or on acceptable margin in relation thereto) between the first layer and a component of the semiconductor device can be obtained. | 7 |
RELATED APPLICATION
This application is a continuation of application Ser. No. 538,973, filed Oct. 5, 1983, now abandoned.
BACKGROUND OF THE INVENTION
Liquified bituminous binders, such as tar, cutback asphalt, emulsified asphalt and the like are applied to road surfaces by various methods and by various types of equipment. Numerous problems are involved in the application of such materials to road surfaces. The bituminous binder must be liquified, thinned or fluidized to a viscosity which is suitable for producing an adequate smooth and uniform spray when a pressurized stream of the liquified binder is discharged from a spray nozzle.
Conventionally a bituminous binder is fluidized or reduced in viscosity by applying heat thereto, or by adding an evaporative solvent or thinner thereto, or by combining the bituminous binder with water and an emulsifying agent.
Adhesion of the bituminous binder to the road surface and to the cover stones is critical to the success of the application of the bituminous binder. Proper adhesion is primarily a function of the viscosity of the bituminous binder during the application process. Under normal circumstances the viscosity of the cutback binders and emulsion binders is adequate to provide good adhesion. However, when pure undiluted binders, such as penetration grade asphalt cements, are melted and liquified by heat and sprayed for sealing in a chip seal process, the pavement surfaces and road stones or aggregates must be warm, dry, and dust free. Such conditions are rareIy found in temperate climates during the construction season. Therefore, pure undiluted asphalt cements are not generally used, and cutback and emulsion materials are preferred.
Emulsion materials conventionally contain one-third water and two-thirds binder. A problem exists in that emulsion materials are generally intolerant to dusty aggregates. Emulsion materials are likely to be washed away by sudden rain showers which occur during application of the emulsion materials.
Solvent cutback binders (bitumens diluted with evaporative solvents) are relatively expensive but are more tolerant of dusty aggregates than emulsion binders. Solvent cutback binders become objectionably messy when exposed to wet road stones or sudden rain showers. Solvent cutback binders require long periods of time to cure as the solvents evaporate. Evaporation of the solvents pollutes the environment.
When pure 100% bituminous binders are used, substantial economy, plus other advantages, are realized.
U.S. Pat. Nos. 2,861,787 and 2,917,395 relate to the process of producing foamed bituminous binders. These patents disclose the mixing of a gas or steam with bitumens which are heated. The mixture is directed through restricted orifices of a foam generating nozzle. The quality of the foamed binder is varied from a multiplicity of finely divided bubbles (a discrete foam) to a coarse "congealed" foam. This variation is accomplished by changing the temperature and pressures of the binder and the gas or steam. The quality of the foamed binder is also variable by changing the geometry and dimensions of the restricted orifices and by changing the gap between a foam generation throat and the internal foam gas injection nozzle.
These patents recognize that the properties of foamed bituminous binders are vastly different from the properties of a liquid binder, in that the foamed bituminous binder is rubbery, extremely sticky, highly cohesive and adhesive. Also, the foamed bituminous binder consists of thin films which have a high degree of natural surface tension and energy forces which are available to coat aggregate surfaces. Also, the foamed bituminous binders penetrate small voids, crevices and agglomerations of duct. Foamed bituminous binders can be applied at relatively low temperatures and in the presence of water.
All of these properties of a foamed bituminous binder combine with the economy available in the use of an undiluted bituminous binder. Thus, the use of a foamed bituminous binder is especially desirable for spraying road surfaces. However, the apparatus and methods disclosed in these patents are only used in stationary mixing situations and are not used for spraying road surfaces.
It is an object of this invention to provide apparatus and a method for producing a controlled foamed bituminous binder and for uniformly applying 100% bituminous binders to road surfaces.
The physical properties of bituminous binders (viscosity-temperature relationships, surface tension, adhesion, and rheological behavior) vary widely, in accordance with such factors as their natural physical properties, crude production methods, methods of refining. Therefore, the foam forming characteristics of each bituminous binder varies widely. It is therefore another object of this invention to provide foam forming apparatus which is easily and readily adjusted to produce a foamed bituminous binder of proper characteristics regardless of the physical properties of the bituminous binder.
Other objects and advantages of this invention reside in the construction of parts, the combination thereof, the method of production and the mode of operation, as will become more apparent from the following description.
SUMMARY OF THE INVENTION
The apparatus of this invention comprises means for uniformly applying bituminous binders to road surfaces. The invention includes means for introducing a gas, such as steam, into the bituminous binder material as the binder material in a fluid state flows toward a road surface. The gas is mixed with a bituminous binder material to form a foam which is sprayed upon the road surface.
BRIEF DESCRIPTION OF THE VIEWS OF THE DRAWINGS
FIG. 1 is a perspective view of apparatus of this invention for producing and uniformly applying foamed bituminous binders to road surfaces.
FIG. 2 is a greatly enlarged perspective view of a portion of the apparatus of FIG. 1.
FIG. 3 is an enlarged sectional view taken substantially on line 3--3 of FIG. 2.
FIG. 4 is a sectional view taken substantially on line 4--4 of FIG. 3.
DETAILED DESCRIPTION OF THE INVENTION
The apparatus shown in FIG. 1 comprises a truck 10, provided with a support bed 12. Mounted upon the support bed 12 is a tank 16, which is adapted to contain bitumen binder material. Means, not shown, is employed to heat the tank 16 and the material therein. Also mounted upon the bed 12 is a tank 18 adapted to contain water and a boiler or steam generator 20 for heating water which flows from the tank 18, for producing steam. Also mounted upon the bed 12 is an engine 24 and a pump 28 operated thereby.
Extending across the rear portion of the truck 10 below the bed 12 is a distributor conduit 30, shown in FIGS. 2 and 3. The distributor conduit 30 is connected to a main line 34 which is connected in a manner not shown to the pump 28. Also extending across the rear portion of the truck 10 below the bed 12 is a distributor conduit 40, shown in FIGS. 2 and 3, which is connected to the boiler 20.
Attached to the distributor conduit 30 and extending therefrom are a plurality of spaced-apart relatively short connector pipes 46. Joined to each connector pipe 46 is a valve housing 48 provided with a valve 50 therein. Each valve 50 has a valve stem 54 attached to a handle 58. Each valve housing 48 has an outlet portion 48a.
Attached to the distributor conduit 40 are a plurality of spaced-apart short pipes 66, each of which has an adapter pipe 68 attached thereto. Each adapter pipe 68 is attached to a mixer housing 70. The upper portion of each mixer housing 70 is attached to the outlet portion 48a of a valve housing 48. Within the upper part of each mixer housing 70 and within the respective valve housing 48 is a flow restrictor 72 provided with an orifice 74.
Each mixer housing 70 has a transverse tube 76 therein which is joined to its respective adapter pipe 68. The transverse tube 76 within each mixer housing 70 has joined thereto a longitudinal tube 80, which extends from the transverse tube 76. The lower part of each mixer housing 70 is provided with a threaded portion 84 to which is threadedly attached a director cap 88. Within each director cap 88 is a throat member 90 provided with a passage 92 therethrough. The throat member 90 has a conical upper surface 93, which encompasses the lower portion of its respective longitudinal tube 80. Attached to the lower portion of each director cap 88 is a nozzle 94 provided with a slot shape opening 96 at the lower portion thereof, as shown in FIGS. 3 and 4.
Attached to the exterior surface of each mixer housing 70 is a resilient strip 97. Around the exterior of each director cap 88 is a series of vertical slots 99. The respective resilient strip 97 is positionable within one of the slots 99 to secure the rotative position of the director cap 88 with respect to the mixer housing 70 to which the director cap 88 is attached. A threaded stud 100 extends through each resilient strip 97 and is attached to the respective mixer housing 70. A wing nut 102 is threadedly attached to each stud 100 and is engageable with the respective resilient strip 97 to retain the resilient strip 97 in one of the slots 99.
As shown in FIG. 2, the handles 58 of the valve stems 54 are joined together with a connector bar 108.
Operation
Heated bitumen, illustrated by arrows 114, flowing from the tank 16 is forced by the pump 28 into the distributor conduit 30. The bitumen 114 flows from the distributor conduit 30 into the short connector pipes 46, then into the respective valve housing 48 and through the valve 50 thereof. The flow of the bitumen 114 is restricted by the orifice 74 in the restrictor 72. Thus, the orifice 74 is restrictive and is always completely filled with bitumen 114 flowing therethrough. The bitumen 114 flows from the restrictor 72 into the mixer housing 70. The bitumen 114 flows around the transverse tube 76 and along and around the longitudinal tube 80. The bitumen 114 then is directed by the conical surface 93 into the passage 92. However, prior to flow of the bitumen 114 into the passage 92, the bitumen 114 is engaged by steam 126 which flows from the steam generator 20 into the conduit 40, through the adapter pipe 68 and into the transverse tube 76. The steam 126 then flows through the longitudinal tube 80 and engages the bitumen 114 adjacent the conical surface 93 of the throat member 90. In this region the steam 126 mixes with the bitumen 114 and a foam 136 is formed and flows through the passage 92 to the nozzle 94. The foam 136 then flows through the nozzle 94 and outwardly through the slot 96 thereof.
The nozzles 94, as illustrated in FIG. 2 are rotatively positioned so that the slot shape opening 96 therein directs the foam 136 in a flow pattern which does not interfere with the flow pattern of the adjacent nozzle 94. Thus, as illustrated in FIG. 1 a road surface 150 is coated with the foam 136. Thus, the advantages of coating a road surface with a foam as discussed above are obtained.
The characteristics of the foam 136 depend upon the length and area of the passage 92. The characteristics of the foam 136 also depend upon the spacing between the longitudinal tube 80 and the conical surface 93. The spacing between the tube 80 and the conical surface 93 is adjustable by rotative movement of the director cap 88 with respect to the mixer housing 70. Such rotative movement of the mixer housing 70 is accomplished by first loosening the wing nut 102, permitting the resilient strip 97 to be positioned within another slot 99 as the mixer housing 70 is rotated.
The restrictor 72 and the throat member 90 are easily and readily removable and replaceable as desired.
All of the valves 50 are simultaneously adjustable by longitudinal movement of the connector bar 108 to control the volume of flow of the bitumen 114 into the mixer housing 70.
Although the preferred embodiment of the apparatus and method for producing and applying foamed bituminous binders according to this invention has been described, it will be understood that within the purview of this invention various changes may be made in the form, details, proportion and arrangement of parts, the combination thereof, and the mode of operation, which generally stated consist in the apparatus and method within the scope of the appended claims. | Apparatus and a method for coating a road surface with bitumen binder material. The apparatus includes distribution conduit members for conducting bitumen material in a fluid state from a continuous source thereof and distribution conduit members for conducting gas, preferably steam, from a continuous source thereof. A plurality of mixer housings are joined to the conduit members and receive bitumen binder material and gas. The apparatus is carried by a vehicle which travels over a road surface. The bitumen binder material and the gas are mixed and sprayed upon the road surface as the vehicle travels over the road surface. | 4 |
CROSS REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of U.S. provisional application No. 60/689,369 filed Jun. 10, 2005, which is herein incorporated by reference in its entirety.
BACKGROUND OF THE INVENTION
This invention relates generally to radar systems, and more particularly to methods and systems that utilize Doppler prediction to set a height of fusing, for example, for a radar based weapon system.
A radar based weapon system is configured to fuse the weapon of the system at various low altitudes so that the weapon will have optimum impact. A dual antenna (i.e. one transmit antenna and one receive antenna) radar system installation within the weapon system that has sufficient separation between the two antennas is not practical for smaller weapon systems. One reason separation between the antennas is important is to reduce an antenna leakage signal that propagates between the two antennas. Sufficient antenna separation to measure elevations near or at ground level such that antenna leakage signals do not interfere with altitude measurements typically cannot be efficiently incorporated into smaller weapon systems. In these smaller weapon systems there is simply not enough room to adequately separate the two antennas.
In smaller weapons systems that incorporate two antennas, the two antenna apertures are necessarily located near one another other which significantly increases the antenna leakage signal. Therefore, with a dual antenna weapon system it is difficult to accurately measure certain low altitudes because the antenna leakage signals interfere with time coincident ground return signals.
A single antenna installation using a duplexer is even more difficult to implement in smaller weapons. The reason is that one antenna systems do not even exhibit some of the inherent antenna leakage isolation found in the dual antenna systems. Rather, signals similar to leakage signals are internal to the radar. As a result, it is also difficult for a one antenna radar sensor on a small weapon system to measure altitudes near or at ground level.
BRIEF SUMMARY OF THE INVENTION
In one aspect, a method for controlling a detonation altitude of a radar equipped munition is provided. The method comprises calculating a velocity of the munition while the munition is at an altitude greater than the desired detonation altitude and determining when the munition is at a reference altitude. The method also includes calculating a time representing when the vehicle will reach the desired detonation altitude based on the calculated velocity and determined reference altitude and generating a fusing signal to detonate the munition after the calculated time has passed.
In another aspect, a munition comprises a sequencer, a radar receiver, a velocity detector, and a time delay controller. The sequencer is configured to receive a detonation altitude for the munition. The radar receiver comprises a radar range gate programmed with a first altitude and a reference altitude. The velocity detector is configured to determine a velocity of the munition based on radar ground return signals passed through the range gate at the first altitude The time delay controller is configured to generate a detonation signal for the munition based on the programmed detonation altitude, a velocity of the munition, and a reference altitude of the munition.
In still another aspect, a radar processor for controlling detonation of a munition is provided which is configured to receive a detonation altitude from an external source. The radar processor is configured to set a first range gate and a reference range gate based on the received detonation altitude, cause a radar transmitter to operate in a continuous wave mode, for a predetermined period, upon receipt of radar return signals through the first range gate, calculate a velocity of the munition from continuous wave return signals, and calculate a time delay for outputting a detonation signal based on the received detonation altitude, the calculated velocity, and a reference altitude of the munition, the altitude of the munition calculated based upon receipt of radar return signals through the reference range gate.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of a radar system for fusing weapon systems at or near ground level altitudes.
FIG. 2 is an illustration of transmit and receive spectrums for the system of FIG. 1 .
FIG. 3 is an illustration of timing signals present in the system of FIG. 1 .
DETAILED DESCRIPTION OF THE INVENTION
The methods and systems described herein provide a solution for weapon system fusing at low altitudes by measuring a precision reference altitude where antenna leakage interference is not present and measuring the velocity of the vehicle as it approaches the ground. Once velocity of the munition is determined, the munition continues toward the ground until it encounters a ground return that is time coincident with a preset reference altitude gate, establishing the precision reference altitude. From these two measurements, a time delay can be used to accurately predict when the weapon system will attain an altitude at or near ground level, and a timing sequence is started. As a result, antenna leakage signals do not interfere with the operation of the sensor.
A programmable sequencer provides the capability to program a desired detonation altitude, which is sometimes referred to as a height of fuse (HOF), prior to launch. FIG. 1 is a block diagram of a radar based fusing system 10 incorporating such a sequencer. Referring specifically to FIG. 1 , an RF oscillator 12 provides the frequency source for transmission through transmit antenna 14 and for down conversion of the radar return pulse received at receive antenna 16 . The frequency is down converted at mixer 18 and the frequency from RF oscillator 12 is provided to mixer 18 through power divider 20 . Modulation switch 22 provides pulse modulation of the signals to be transmitted. A buffer amplifier 24 provides isolation for RF oscillator 12 from the impedance variations caused by modulation switch 22 to reduce oscillator frequency pulling during transmission to a tolerable level, keeping the return frequency within a pass band of the receiver portion of system 10 .
The down converted radar return frequency output by mixer 18 is at a Doppler shift proportional to the downward velocity of the vehicle and is sometimes referred to as the Doppler frequency. The Doppler frequency, f d , is equal to 2×velocity/wavelength. In one embodiment, the transmitter frequency (fo) is at 4.3 GHz and therefore, the wavelength is c/fo, where c is the speed of light. For example, at a velocity of 2461 Ft/sec (i.e. 750 m/sec), and 4.3 Ghz oscillator frequency (i.e. wavelength of 0.229 feet), the Doppler shift is f d =2×2461/0.229, or 21,493 Hz at an output of the mixer 18 as illustrated in FIG. 2 . Since the trajectory could be 10° from Nadir, then the maximum closing velocity would be 738 m/sec and the resulting Doppler frequency would be 21,149 Hz.
The low end of the Doppler bandwidth is determined when the velocity of the vehicle is at its minimum, for example, 820 ft/sec (i.e. 250 m/sec), which results in a Doppler frequency of 7,161 Hz. Again, with trajectory angle of 10°, the minimum closing velocity would be 246 and the minimum Doppler frequency is 7,046 Hz. The maximum Doppler bandwidth is therefore 21,493−7,046=14,447 Hz.
Referring back to FIG. 1 , system 10 includes a velocity detector 30 . A Doppler gate 32 is set at a higher altitude (i.e. the first altitude) and the Doppler frequency is measured. This Doppler frequency is used by velocity detector 30 to calculate the velocity. For low altitudes or penetration detection, a time delay can be calculated by time delay controller 33 , based on the velocity along with knowing when the munition is at the reference altitude, and then used to accurately generate the height of fuse (HOF) signal at the desired detonation altitude.
Also, the Doppler frequency signal is peak detected with peak detector 34 , integrated at integrator 35 , and threshold detected at comparator 36 so that when the ground return signal passes through Doppler gate 32 , at a time coincident with a reference HOF gate, then a fusing signal 40 can be generated. Doppler gate 32 can be pre-set with a reference HOF gate at any time that is consistent with a position within the fusing range of the weapon to be detonated.
FIG. 3 is a timing diagram 100 illustrating a sequence of events which occurs within system 10 (shown in FIG. 1 ) after launch of such a system. For example, if the vehicle is at an altitude of greater than 200 feet (i.e. a radar ground return time of 406.7 nsec), the transmitter of system 10 is operating in a pulse mode. When operating in the pulse mode, the pulse width is narrow, for example, about 25 nanoseconds, and at a pulse repetition frequency (PRF) of about 40 KHz. This PRF is about twice the maximum Doppler frequency. The ground return pulse 102 is received at receive antenna 16 (shown in FIG. 1 ) in excess of 406.7 nanoseconds from the time of transmission.
As the vehicle continues toward the ground, the ground return signal will become coincident with a programmed ground pulse return time within Doppler gate 32 (shown in FIG. 1 ), and illustrated in FIG. 3 as Doppler gate pulse 104 . When the ground return pulse occurs 102 within the gated time (i.e., during the Doppler gate pulse 104 ), the transmitter of system 10 is configured to revert from a gated or pulsed transmission to a continuous wave (CW) transmission for about 25 milliseconds, shown in FIG. 3 as 106 . During this time, the Doppler frequency based on the CW transmission is accurately measured within system 10 .
At a minimum velocity (i.e. about 250 meters/sec) of the vehicle (e.g., weapon), the Doppler frequency is about 7 KHz, as described above. During the 25 millisecond period, 176 cycles will be sampled with a distribution error of about 0.56% or about 4.6 ft/sec. The distance traveled by the vehicle at this velocity and time is 20.5 feet. At a maximum velocity of the vehicle (i.e. 750 meters/sec), the Doppler frequency is about 21.5 KHz. During the 25 millisecond period of CW transmission, 537 cycles will be sampled with a distribution error of 0.186% or 4.6 ft/sec. The distance traveled by the vehicle at this velocity and time is 61.25 feet. At the end of the 25 milliseconds, the Doppler frequency will be measured and the transmitter will revert back to the pulse mode.
As the vehicle continues toward the ground, the return signal will eventually be coincident with a reference altitude HOF gate 108 that has been programmed into system 10 , for example, programmed into Doppler gate 32 . Reference altitude HOF gate 108 is precisely placed in time, for example, at 203.34 nanoseconds after transmission of a radar pulse, which is representative of the return time for a radar pulse from a vehicle at about 100 feet in altitude. By knowing the precise reference altitude of the vehicle, based on a ground return pulse being received when HOF gate 108 is active, and the velocity of the vehicle relative to the ground based on the Doppler measurement during the CW transmission, then delays, for example, using time delay controller 50 (shown in FIG. 1 ) can be established. The delay is the time that it will take the vehicle to travel from the altitude that is coincident with the reference altitude HOF gate 108 to the desired detonation altitude, based on the vehicle velocity. Programming of such a delay results in generation of a fusing signal which occurs at the programmed detonation altitude setting (i.e. between 0 and 25 meters).
With an upper cutoff frequency of the Doppler frequency of 21,493 Hz, the pulse repetition frequency (PRF) should be set at about two times the Doppler frequency or about 40 KHz. This PRF will result in a first spectral line that is comfortably outside the Doppler bandwidth. If the transmitter pulse width is 25 nanoseconds, then the duty cycle is only 0.1%. With a low duty cycle, the gated system should provide additional jam immunity.
The above described gating and ground return signal processing configuration allows reliable operation, for example programmable detonation altitudes, down to zero feet altitude with a much lower antenna spacing than in previous systems. If there is no motion of the vehicle (munition), the output of the mixer will be 0 Hz (DC). This is the case for antenna leakage interference. Varying the phase of the local oscillator signal of mixer 18 signal results in the DC level of the antenna leakage signal varying. The DC level is set to zero by fixing the line length from power divider 20 to mixer 18 to provide a 180 degree shift with respect to the antenna to antenna leakage path length.
The above described system satisfies the need for a height of fuse (HOF) radar system for small munitions that operates at selected altitudes near and at ground level. Both pulse gating and Doppler frequency measurements are used to provide fusing of the munition at accurate altitudes. Fusing can be obtained down to zero feet with much closer antenna spacing or even with a single antenna by using coherent processing, Doppler isolation, and Doppler velocity prediction by avoiding altitude measurements that may be coincident with the receiving of an antenna leakage signal. The result is a low cost and small size sensor through incorporation of a single-frequency-oscillator design which provides both the transmit source and receiver down conversion source. A small, low cost, and low transmitter power is achievable through the incorporation of the signal oscillator, radar receiver processing technique, which takes advantage of the positive ground return Doppler shift associated with the downward motion.
While the invention has been described in terms of various specific embodiments, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the claims. | A method for controlling a detonation altitude of a radar equipped munition is described. The method includes calculating a velocity of the munition while the munition is at an altitude greater than the desired detonation altitude, determining when the munition is at a reference altitude, and calculating a time representing when the vehicle will reach the desired detonation altitude based on the calculated velocity and determined reference altitude. The method also includes generating a fusing signal to detonate the munition after the calculated time has passed. | 5 |
CROSS-REFERENCE TO RELATED APPLICATION
This application claims the priority to Chinese Patent Application No. CN201410064305.9, filed Feb. 25, 2014, in the State Intellectual Property Office of P.R. China, which is hereby incorporated herein in its entirety by reference.
FIELD
The present invention belongs to the ramie technical field and relates to, in particular, a method for degumming the ramie phloem fibers.
BACKGROUND
Global fossil resources are going to be exhausted, and the environmental pollution is increasingly severe. Solving the problems of the resources and environment is the important task for the economic sustainable development in 21 st century. However, the chemical fibers with petroleum as the starting material comprise about 67% in the total amount of the textile industry in China, the yield of which is over 50% in the world. It will be faced a severe problem in ensuring the petroleum supply in a long term and steadily. It has been an international trend to change the present situation that the petroleum resources are deeply relied on by the chemical fiber industry in China or even the world, and develop the utilization of the natural fibers. 2009 has been designated as the “International Year of Natural Fibers”. The usage of natural fibers has increased by 8% and 15% every year in the world and China, respectively. The yield of cotton, the main natural fibers in China, is about 6 million tons per year with a gap of about 6 to 8 million tons that is not likely to be compensated by planting cotton in the cereals cropland instead. The productivity has reached the plateau for other natural fibers in China, such as silk and wool, both of which have a yield of 100,000 tons per year. The bast fiber crops are cultivated in extensive conditions and suitable to be planted in various places, and have a great potential to be developed in the industrial scale. The most advantageous bast fiber crop is ramie. From of old, ramie is the typical crop mainly used in textile in China and known as “China grass” overseas. China has 90% of the ramie yield in the world and extremely high international competitive capacity that 80% of the ramie products are outputted to comprise over 60% of the global textile trade volume. There are 459 relatively large ramie textile and/or ramie textile manufacturing enterprises in China, offering nearly 1 million jobs.
The ramie industry is the traditional national industry in China and belongs to the labour intensive industries. In China, the employees in the ramie industry chain are up to several millions. The ramie dress has the advantages such as being stiff and neat, elegant, light, cool, breathable and anti-bacterial, and belongs to top grade consumer goods. The utilization of ramie fiber resources is turning from the traditional textile field to the biomass energy sources and biomaterials. Both the ramie materials and the ramie products have a broad market prospect.
The degumming of the ramie is an important step in the ramie processing. At present in China, most of the ramie processing enterprises adopt the chemical degumming, involving acid immersing, alkali boiling, and hammering-and-washing steps, which not only renders the degumming process long, the process steps complicated, the energy and water consumption high, and the pollution severe, but also causes damage to the ramie fibers and lowers the fiber quality. The biological degumming is focused in the clean production technology studies of the phloem fibers of the bast fiber crops at home and abroad, and is by the mechanism that the microorganisms and their secreted extracellular enzyme(s) are utilized to allow a series of reactions occur in relatively mild conditions so as to degrade the ramie phloem gum and release the fibers. The biological degumming is believed to be most possibly used in production practice in place of chemical degumming due to the avoidance of strong acids and alkalis, saving energy and water and little environmental pollution. The biological degumming of the ramie has been studied for over 80 years in China. Mainly, the superior degumming bacteria are screened from the nature and incubated into high-efficient degumming strains by physical or chemical mutagenesis, and then, the scaled-up bacterium-and-enzyme mixed liquor or the critical degumming enzyme(s) isolated therefrom is used for degumming. In the past decades, a number of degumming bacteria have been obtained from the microorganism resources, wherein the Erwinia carotovora strain T85-260 screened by the Institute of Bast Fiber Crops, Chinese Academy of Agricutral Sciences, the Bacillus alcalophilus strain screened by Wuhan University, the Bacillus alcalophilus strain screened by Shandong University, and the wild Bacillus cereus strain screened by Qingdao Continent Biotech Co., Ltd have ever been proceeded to the production test stage, and the others are still in the laboratory stage.
In the last 90s, the commercial production test has been performed for the biological degumming technologies. The patent “A technology for degumming the ramie jointly by bacteria and chemistry” (CN85103481) has been extended in 5 enterprises, and the patent “A process and equipment for biologically degumming the ramie” (CN95112564.8) has been tested for production in 6 enterprises including the Number 2 and 3 Ramie Textile Factories of Ruanjiang City, Hunan Province. The attempts failed mainly because the seed production technology is difficult to be mastered and the degumming capacity is not sufficient. The patent CN01106884.2 has been tested in Number 2 Ramie Textile Factory of Ruanjiang City, and the patent CN97109044.0 has been tested for production in Jiangxi Enda Hometextile Co., Ltd. These tests were in the joint manner of biological-and-chemical degumming. The large-scale production test of purely biological degumming was started in 2007 in the Star Textile Factory of Ruanjiang, Hunan. However, it has now been forced to change to joint biological-and-chemical degumming, which is mainly because the degummed ramie by purely biological degumming is not ideal and the products produced using the same are not welcome in the market.
SUMMARY OF THE INVENTION
The technical problem to be solved by the present invention is to provide a chain, continuous and no-waste technology for degumming and fiber-separating the ramie, which solves the problems resulted from the discharge of the residual liquid after the traditional batch single-tank treatment, such as high consumption of chemicals and the production of highly concentrated wastewater, to reach the bast fiber processing with zero discharge and solve the problems, such as high consumption of water and severe pollution, in the existing ramie degumming process.
The present invention solves the technical problem by the following solution:
A chain, continuous and no-waste method for degumming and fiber-separating the ramie according to the present invention, including:
(1) waste alkali bath step, in which the raw fibers are immersed in the alkaline wastewater discharged from the alkali-hydrogen peroxide one bath scouring-bleaching at ambient temperature for 8 h;
(2) anaerobic circle step, in which the raw fibers treated in the waste alkali bath are immersed in the anaerobic water pool in a bath ratio of 1:15 to 25, and washed at ambient temperature for 8 h;
(3) aerobic circle step, in which the raw fibers washed in the anaerobic water pool are immersed in the aerobic water pool in a bath ratio of 1:15 to 25, and washed at ambient temperature for 8 h;
(4) alkali-hydrogen peroxide one bath scouring-bleaching step, in which the raw fibers treated in the aerobic circle step are immersed in a solution comprising 1 to 10 g/L NaOH and 0 to 2 g/L H 2 O 2 in a bath ratio of 1:15 to 25, and reacted at the temperature of 70 to 100° C. for 2 h;
(5) fiber-separating and washing step, in which the raw fibers washed in the alkali-hydrogen peroxide one bath scouring-bleaching step are treated by the fiber-separating and washing device with a washing time of 4 h, which step can be performed either by rolling and rubbing manually or in a mechanical way;
(6) bio-enzyme washing step, in which the raw fibers treated in the fiber-separating and washing step are immersed in a solution having a cellulose concentration of 5 to 30 U in a bath ratio of 1:15 to 25 and reacted at the temperature of 55° C. for 2 h to reach the no-waste degumming and fiber-separating of the raw ramie fibers, depending on the quality requirements.
According to the present invention, a disc is used as the device units in a chain connection in the process of the no-waste degumming and fiber-separating of the raw ramie fibers, rendering a continuous operation; the ramie degumming process and the degumming wastewater treatment are performed integratively, and the effluent from the alkali-hydrogen peroxide one bath scouring-bleaching is introduced into the waste alkali bath and used for the immersion of the raw fibers; the water used in the anaerobic washing step is circulated with the anaerobic pool for sewage treatment; the water used in the aerobic washing step is circulated with the aerobic pool for sewage treatment; the effluents from the waste alkali bath, fiber-separating and washing, and bio-enzyme washing are recycled after treatment in the sewage treatment system, and no sewage is discharged.
The effluent from the alkali-hydrogen peroxide one bath scouring-bleaching is highly polluted wastewater, and a majority of the COD therein can be precipitated by flocculation after being used in the waste alkali bath, to form the sludge to be treated separately, and the supernatant is then discharged into the sewage treatment system so as to reduce the load of the subsequent sewage treatment system.
The degumming process is a continuous disk operation, and the chemicals in the alkali-hydrogen peroxide one bath scouring-bleaching step can be repeatedly used for many times to reduce the discharge of the degumming chemicals every time.
The soluble gum can be partially squeezed out from the ramie in the mechanical squeezing and water flow washing process to fiber-separate the raw fibers partially.
The cellulase is a normal cellulase, an acidic cellulase, a neutral cellulase or an alkaline cellulase, and not limited by the pH value.
The fiber-separating and washing device can be the ramie fiber back washing device Model ZMXFC-1 developed jointly by Wuhan Textile University and Xinnong Ramie Co., Ltd.
The present invention has the following advantages as compared to the prior art:
1) The existing chemical degumming process is a batch operation, and the solution containing sodium hydroxide and degumming aids is discharged directly every time after the completion of degumming, which leads to the failure of recycling the degumming chemicals and the discharge of a large amount of highly concentrated wastewater. The degumming process of the present invention is a continuous disc operation, and the chemicals in the alkali-hydrogen peroxide one bath scouring-bleaching step are repeatedly used for many times, which reduces the discharge of the degumming chemicals every time, and perform the step with most severe pollution separately to reduce the load of the subsequent sewage treatment systems.
The separate performation of the step with most severe pollution in the degumming process reduces the difficulty of treating the wastewater coupled with the same. The effluent from the alkali-hydrogen peroxide one bath scouring-bleaching is highly polluted wastewater, and a majority of the COD therein are precipitated by flocculation after being used in the waste alkali bath, to form the sludge to be treated separately, and the supernatant is then discharged into the sewage treatment system so as to reduce the COD concentration in the influent of the degumming wastewater treatment system and reduce the treatment difficulty and the treatment cost.
2) The existing biological degumming process suffers from the product homogeneity problem because the seed activation, amplifying culture, and degumming needs to be performed again in every degumming, which cannot ensure the complete consistency between the seed concentrations used in every time and thus results the significantly different batches of degummed ramie by biological degumming. In the present invention, the water used in the anaerobic washing step is circulated with the anaerobic pool for sewage treatment, and the water used in the aerobic washing step is circulated with the aerobic pool for sewage treatment. Since the degumming wastewater treatment is continuously performed, the anaerobic and aerobic washing steps not only wash away partially the alkali liquid on the raw ramie fiber left after the waste alkali bath step, but also have the effect of the biological treatment, without suffering from the homogeneity problem of the microorganism treatment.
3) The severe pollution problem with the ramie degumming is solved. For the production of every one ton of the degummed ramie, the present method discharges barely the degumming wastewater and reaches the raw ramie fiber degumming process with zero discharge as compared to the discharge of 500 tons of wastewater for the production of one ton of the degummed ramie in the traditional degumming processes.
4) The present invention uses a disc as the degumming device unit and connects each of the degumming steps by a chain to degum continuously. The degumming is performed in a coupled physical, chemical, and biological way and the degumming operation is performed gradually. The degumming efficiency is improved and the degumming cost is reduced.
In a word, the ramie degumming process and the degumming wastewater treatment are performed integratively according to the present invention. The degumming wastewater is entirely recycled after treatment, without sewage discharge.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic view of the process flow of the chain, continuous and no-waste technology for degumming and fiber-separating the ramie according to the present invention.
FIG. 2 is a schematic view of the structure of the production line.
FIG. 3 is a schematic view of the sequencing batch decorticator in FIG. 2 .
FIG. 4 is a schematic view of the automatic stem separation machine in FIG. 2 .
FIG. 5 is the roller type transport platform in FIG. 2 .
FIG. 6 is a schematic view of the stamping machine in FIG. 2 .
FIG. 7 is a schematic view of the structure of the washing and degumming section in FIG. 2 .
FIG. 8 is a schematic view of the structure of the ramie fiber cleaning unit in FIG. 2 .
In the figures: 1 . ramie sorting platform; 2 . sequencing batch decorticator; 3 . automatic ramie stem separation machine; 4 . first mechanical hand; 5 . roller type transport platform; 6 . stamping machine; 7 . second mechanical hand; 8 . degumming and washing device; 9 . third mechanical hand; 10 . ramie fiber back washing device; 11 . bast fiber collecting frame of the sequencing batch decorticator; 12 . stem inlet of the sequencing batch decorticator; 13 . stem inlet of the automatic ramie stem separation machine; 14 . bast fiber collecting and transporting configuration of the automatic ramie stem separation machine; 15 . L type roller type transport platform; 16 . I type roller type transport platform; 17 . squeezing platform of the stamping machine; 18 . mechanical hand of the stamping machine; 19 . degumming and washing pool; 20 . chaining transport device; 21 . ramie fiber cleaning tank; 22 . trolley.
DETAILED DESCRIPTION OF THE INVENTION
The present invention adopts the apparatus shown in FIGS. 2-8 . This apparatus is an automatic degummed ramie production line used for separating the boon, bark and fiber layer of the ramie and degumming and fiber-separating, and washing and recovering the ramie fibers. In this production line, ramie is firstly sorted and transported by the sorting unit. The peeling unit peels off the bast fibers from the boon and collects the same separately to the ramie frame, namely the bast fiber collecting frame of the sequencing batch decorticator. The transport unit transports the ramie frame to the degumming unit for squeezing and degumming processing. The ramie fibers are then cleaned and recovered by the bast fiber cleaning unit.
The sorting unit is constituted by the ramie sorting platform 1 , which is located left to the automatic ramie stem separation machine 3 . The ramie sorting platform 1 can be the ramie sorting platform Model ZMFJ-1 developed jointly by Wuhan Textile University and Xinnong Ramie Co., Ltd, that is mainly constituted by sorting platform pivot, sorting platform driving mechanism, flat belt, and sorting platform stand.
The peeling unit is constituted by the sequencing batch decorticator 2 and three machines with the same structure, namely the automatic ramie stem separation machines 3 , wherein the sequencing batch decorticator is located the beginning end of the L type standing roller type transport platform 15 , followed immediately by the automatic ramie stem separation machine. The sequencing batch decorticator 2 can be the sequencing batch decorticator Model XBM-1D developed jointly by Wuhan Textile University and Xinnong Ramie Co., Ltd, that is mainly constituted by the bast fiber collecting frame of the sequencing batch decorticator 11 , the stem inlet of the sequencing batch decorticator 12 , the hoisting device, the rotating device, boon separating and recovering device, and the bast fiber cutting device. The automatic ramie stem separation machine 3 can be the automatic ramie stem separation machine Model ZDZMF-3 developed jointly by Wuhan Textile University and Xinnong Ramie Co., Ltd, that is mainly constituted by the stem inlet of the automatic ramie stem separation machine 13 , the separation machine stand, the boon-and-bark separating device of the separation machine, and the bast fiber collecting and transporting mechanism. The L type standing roller type transport platform 15 can be the standing roller type transport platform Model GZSS-L developed jointly by Wuhan Textile University and Xinnong Ramie Co., Ltd, that is mainly constituted by the driving mechanism, the roller, and the stand.
The transport unit is constituted by roller type transport platform 5 and chaining transport device 20 , wherein the roller type transport platform 5 is distributed right to the automatic ramie stem separation machine 3 and both front and rear sides of the stamping machine 6 , and the chaining transport device 20 is located over the degumming and washing pool 19 . The roller type transport platform 5 can be the roller type transport platform Model GZSS-1 developed jointly by Wuhan Textile University and Xinnong Ramie Co., Ltd, that is mainly constituted by the driving mechanism, the roller, and the stand. The chaining transport device 20 can be the chaining transport device Model GLSS developed jointly by Wuhan Textile University and Xinnong Ramie Co., Ltd, that is mainly constituted by the stand, transport track, and the slidable hook.
The degumming unit is constituted by the degumming and washing pool 19 and four machines with the same structure, namely the stamping machine 6 , wherein the stamping machine 6 is located at the end of the roller type transport platform 5 , and the degumming and washing pool 19 is located 30 m away and right front of the stamping machine 6 . The degumming unit performs firstly the stamping machine squeezing processing in the degumming process, by which 80% of the gum can be removed, and then performs the degumming and washing processing. With the whole process, the degumming ratio can be up to 95% and the polluted wastewater caused by degumming can be reduced significantly. The stamping machine 6 can be the stamping machine Model XZMFX-3 developed jointly by Wuhan Textile University and Xinnong Ramie Co., Ltd, that is mainly constituted by the stamping machine stand, the hydraulic motor, the squeezing platform of the stamping machine 17 , the mechanical hand of the stamping machine 18 , the squeezing and impacting device of the stamping machine.
The ramie frame convey unit is constituted by the first mechanical hand 4 and the second mechanical hand 7 , wherein the first mechanical hand 4 is located over the roller type transport platform 5 , fixed to the ground by the stand and across the L type standing roller type transport platform 15 . The second mechanical hand 7 is located at the rear of the roller type transport platform 5 and fixed to the ground by the stand.
The bast fiber cleaning unit is constituted by the third mechanical hand 9 and two machines with the same structure, namely the ramie fiber back washing device 10 , wherein the third mechanical hand 9 is located left to the fiber back washing device and fixed to the ground by the stand. The bast fiber cleaning unit can clean up the residual chemicals on the ramie fibers in the ramie fiber cleaning process. At the same time, the process of performing batch washing can separate the residual boons in the ramie fibers by washing. The ramie fiber back washing device 10 can be the ramie fiber back washing device Model ZMXFC-1 developed jointly by Wuhan Textile University and Xinnong Ramie Co., Ltd, that is mainly constituted by the ramie fiber cleaning tank, the water supply device, the stand, and the cap inversing device. The soluble gum can be partially squeezed out from the ramie in the mechanical squeezing and water washing process to fiber-separating the raw fibers partially.
The ramie fiber back washing device 10 is located the very right side of the factory building and near the chaining transport device.
All of the first mechanical hand 4 , the second mechanical hand 7 , and the third mechanical hand 9 are the JXS-01 series mechanical hands developed jointly by Wuhan Textile University and Xinnong Ramie Co., Ltd, which are controlled using hydraulic system, and are steady, safe and reliable in working process.
In the apparatus of the present invention, the degumming and washing device 8 is right below the chaining transport device 20 in FIG. 7 .
In the apparatus of the present invention, the bast fiber collecting and transporting configuration of the automatic ramie stem separation machine 14 is at the right end of the automatic ramie stem separation machine 3 in FIG. 4 .
In the apparatus of the present invention, the I type roller type transport platform 16 is right over the L type roller type transport platform 15 in FIG. 5 .
In the apparatus of the present invention, the ramie fiber cleaning tank 21 is at the lower part of the ramie fiber back washing device 10 in FIG. 8 .
In the apparatus of the present invention, the trolley 22 is at the left part of the ramie fiber back washing device 10 in FIG. 8 .
The present invention will be further described below in combination with Examples and accompanied drawings, without limiting the present invention.
Example 1
The degumming processing was performed using the process flow shown in FIG. 1 and the apparatus shown in FIGS. 2-8 . The manually peeled ramie marketed in Xianning City, Hubei Province was purchased. 500 kg of the manually peeled ramie was placed into the waste alkali bath pool in a bath ratio of 1:20 (weight volume ratio) and immersed for 8 h. The solution in the pool was the alkaline wastewater discharged from the alkali-hydrogen peroxide one bath scouring-bleaching. Then, the degumming wastewater was precipitated by separate treatment, after which the resulted sludge was burnt directly and the supernatant was discharged into the sewage treatment unit.
The degumming wastewater was pumped into the sewage treatment unit, followed by the sewage treatment in the conditioning pool, the anaerobic pool, the first precipitation pool, the aerobic pool, the second precipitation pool etc.
The manually peeled ramie treated in the waste alkali bath was placed into the anaerobic washing pool in a bath ratio of 1:20 (weight volume ratio) and washed by immersion at ambient temperature for 8 h. The anaerobic washing pool was circulated with the anaerobic pool for sewage treatment, and the solution used for washing was with the same composition as that of the solution in the anaerobic pool for sewage treatment. Then, the manually peeled ramie treated in the anaerobic washing pool was placed into the aerobic washing pool in a bath ratio of 1:20 (weight volume ratio) and washed by immersion at ambient temperature for 8 h. The aerobic washing pool was circulated with the aerobic pool for sewage treatment, and the solution used for washing was with the same composition as that of the solution in the aerobic pool for sewage treatment. The aerobic washing pool was kept in the aerated state in the immersion period with the aerated dissolved oxygen of 3 to 5 mg/L.
Next, the manually peeled ramie treated in the aerobic washing pool was placed into the alkali-hydrogen peroxide one bath scouring-bleaching pool in a bath ratio of 1:20 (weight volume ratio), and immersed in a solution of 2 g/L NaOH and 0.5 g/L H 2 O 2 to react at the temperature of 80° C. for 2 h. The reaction liquid was discharged into the waste alkali bath pool. Then, the manually peeled ramie treated in the alkali-hydrogen peroxide one bath scouring-bleaching pool was placed into the fiber-separating and washing device in a bath ratio of 1:20 (weight volume ratio). The fiber-separating in the present invention can be performed either by rolling and rubbing manually or in a mechanical way. The washing time was 4 h.
Finally, the raw fibers treated by fiber-separating and washing were immersed in a solution with a cellulose concentration of 15 U (International units) in a bath ratio of 1:20 (weight volume ratio) and reacted at the temperature of 55° C. for 2 h so as to perform the bio-enzyme washing.
The effluents from the waste alkali bath, fiber-separating and washing, and bio-enzyme washing were pumped into the conditioning pool for sewage treatment, and treated in the anaerobic pool, the first precipitation pool, the aerobic pool, the second precipitation pool, after which the effluents had a COD of 178, a BOD 5 of 33, a chromaticity of 11, a SS of 29, and a pH of 7.6. The effluents were returned back to the fiber-separating and washing pool for repeated use.
The degummed ramie obtained after dehydration and baking was tested for fiber quality. The results were shown in Table 1.
Example 2
The degumming processing was performed using the process flow shown in FIG. 1 and the apparatus shown in FIGS. 2-8 . The manually peeled ramie marketed in Xianning City, Hubei Province was purchased. 500 kg of the manually peeled ramie was placed into the waste alkali bath pool in a bath ratio of 1:17 (weight volume ratio) and immersed for 8 h. The solution in the pool was the alkaline wastewater discharged from the alkali-hydrogen peroxide one bath scouring-bleaching. Then, the degumming wastewater was precipitated by separate treatment, after which the resulted sludge was burnt directly and the supernatant was discharged into the sewage treatment unit.
The degumming wastewater was pumped into the sewage treatment unit, followed by the sewage treatment in the conditioning pool, the anaerobic pool, the first precipitation pool, the aerobic pool, the second precipitation pool etc.
The manually peeled ramie treated in the waste alkali bath was placed into the anaerobic washing pool in a bath ratio of 1:17 (weight volume ratio) and washed by immersion at ambient temperature for 8 h. The anaerobic washing pool was circulated with the anaerobic pool for sewage treatment, and the solution used for washing was with the same composition as that of the solution in the anaerobic pool for sewage treatment. Then, the manually peeled ramie treated in the anaerobic washing pool was placed into the aerobic washing pool in a bath ratio of 1:17 (weight volume ratio) and washed by immersion at ambient temperature for 8 h. The aerobic washing pool was circulated with the aerobic pool for sewage treatment, and the solution used for washing was with the same composition as that of the solution in the aerobic pool for sewage treatment. The aerobic washing pool was kept in the aerated state in the immersion period with the aerated dissolved oxygen of 3 to 5 mg/L.
Next, the manually peeled ramie treated in the aerobic washing pool was placed into the alkali-hydrogen peroxide one bath scouring-bleaching pool in a bath ratio of 1:17 (weight volume ratio), and immersed in a solution of 2.8 g/L NaOH and 0.5 g/L H 2 O 2 to react at the temperature of 80° C. for 2 h. The reaction liquid was discharged into the waste alkali bath pool. Then, the manually peeled ramie treated in the alkali-hydrogen peroxide one bath scouring-bleaching pool was placed into the fiber-separating and washing device in a bath ratio of 1:17 (weight volume ratio). The fiber-separating in the present invention can be performed either by rolling and rubbing manually or in a mechanical way. The washing time was 4 h.
Finally, the raw fibers treated by fiber-separating and washing were immersed in a solution with a cellulose concentration of 20 U (International units) in a bath ratio of 1:17 (weight volume ratio) and reacted at the temperature of 55° C. for 2 h so as to perform the bio-enzyme washing.
The effluents from the waste alkali bath, fiber-separating and washing, and bio-enzyme washing were pumped into the conditioning pool for sewage treatment, and treated in the anaerobic pool, the first precipitation pool, the aerobic pool, the second precipitation pool, after which the effluents had a COD of 198, a BOD 5 of 40, a chromaticity of 15, a SS of 32, and a pH of 7.2. The effluents were returned back to the fiber-separating and washing pool for repeated use.
The degummed ramie obtained after dehydration and baking was tested for fiber quality. The results were shown in Table 1.
Example 3
The degumming processing was performed using the process flow shown in FIG. 1 and the apparatus shown in FIGS. 2-8 . The manually peeled ramie marketed in Xianning City, Hubei Province was purchased. 500 kg of the manually peeled ramie was placed into the waste alkali bath pool in a bath ratio of 1:22 (weight volume ratio) and immersed for 8 h. The solution in the pool was the alkaline wastewater discharged from the alkali-hydrogen peroxide one bath scouring-bleaching. Then, the degumming wastewater was precipitated by separate treatment, after which the resulted sludge was burnt directly and the supernatant was discharged into the sewage treatment unit.
The degumming wastewater was pumped into the sewage treatment unit, followed by the sewage treatment in the conditioning pool, the anaerobic pool, the first precipitation pool, the aerobic pool, the second precipitation pool etc.
The manually peeled ramie treated in the waste alkali bath was placed into the anaerobic washing pool in a bath ratio of 1:22 (weight volume ratio) and washed by immersion at ambient temperature for 8 h. The anaerobic washing pool was circulated with the anaerobic pool for sewage treatment, and the solution used for washing was with the same composition as that of the solution in the anaerobic pool for sewage treatment. Then, the manually peeled ramie treated in the anaerobic washing pool was placed into the aerobic washing pool in a bath ratio of 1:22 (weight volume ratio) and washed by immersion at ambient temperature for 8 h. The aerobic washing pool was circulated with the aerobic pool for sewage treatment, and the solution used for washing was with the same composition as that of the solution in the aerobic pool for sewage treatment. The aerobic washing pool was kept in the aerated state in the immersion period with the aerated dissolved oxygen of 3 to 5 mg/L.
Next, the manually peeled ramie treated in the aerobic washing pool was placed into the alkali-hydrogen peroxide one bath scouring-bleaching pool in a bath ratio of 1:22 (weight volume ratio), and immersed in a solution of 2.2 g/L NaOH and 0.5 g/L H 2 O 2 to react at the temperature of 80° C. for 2 h. The reaction liquid was discharged into the waste alkali bath pool. Then, the manually peeled ramie treated in the alkali-hydrogen peroxide one bath scouring-bleaching pool was placed into the fiber-separating and washing device in a bath ratio of 1:22 (weight volume ratio). The fiber-separating in the present invention can be performed either by rolling and rubbing manually or in a mechanical way. The washing time was 4 h.
Finally, the raw fibers treated by fiber-separating and washing were immersed in a solution with a cellulose concentration of 18 U (International units) in a bath ratio of 1:22 (weight volume ratio) and reacted at the temperature of 55° C. for 2 h so as to perform the bio-enzyme washing.
The effluents from the waste alkali bath, fiber-separating and washing, and bio-enzyme washing were pumped into the conditioning pool for sewage treatment, and treated in the anaerobic pool, the first precipitation pool, the aerobic pool, the second precipitation pool, after which the effluents had a COD of 162, a BOD 5 of 37, a chromaticity of 17, a SS of 26, and a pH of 7.3. The effluents were returned back to the fiber-separating and washing pool for repeated use.
The degummed ramie obtained after dehydration and baking was tested for fiber quality. The results were shown in Table 1.
Example 4
The degumming processing was performed using the process flow shown in FIG. 1 and the apparatus shown in FIGS. 2-8 . The fresh ramie in the Ramie Planting Field of Xianning City, Hubei Province was reaped. 500 kg of the fresh ramie was placed into the waste alkali bath pool in a bath ratio of 1:25 (weight volume ratio) and immersed for 8 h. The solution in the pool was the alkaline wastewater discharged from the alkali-hydrogen peroxide one bath scouring-bleaching. Then, the degumming wastewater was precipitated by separate treatment, after which the resulted sludge was burnt directly and the supernatant was discharged into the sewage treatment unit.
The degumming wastewater was pumped into the sewage treatment unit, followed by the sewage treatment in the conditioning pool, the anaerobic pool, the first precipitation pool, the aerobic pool, the second precipitation pool etc.
The ramie treated in the waste alkali bath was placed into the anaerobic washing pool in a bath ratio of 1:25 (weight volume ratio) and washed by immersion at ambient temperature for 8 h. The anaerobic washing pool was circulated with the anaerobic pool for sewage treatment, and the solution used for washing was with the same composition as that of the solution in the anaerobic pool for sewage treatment. Then, the manually peeled ramie treated in the anaerobic washing pool was placed into the aerobic washing pool in a bath ratio of 1:25 (weight volume ratio) and washed by immersion at ambient temperature for 8 h. The aerobic washing pool was circulated with the aerobic pool for sewage treatment, and the solution used for washing was with the same composition as that of the solution in the aerobic pool for sewage treatment. The aerobic washing pool was kept in the aerated state in the immersion period with the aerated dissolved oxygen of 3 to 5 mg/L.
Next, the ramie treated in the aerobic washing pool was placed into the alkali-hydrogen peroxide one bath scouring-bleaching pool in a bath ratio of 1:25 (weight volume ratio), and immersed in a solution of 1.8 g/L NaOH and 0.5 g/L H 2 O 2 to react at the temperature of 80° C. for 2 h. The reaction liquid was discharged into the waste alkali bath pool. Then, the manually peeled ramie treated in the alkali-hydrogen peroxide one bath scouring-bleaching pool was placed into the fiber-separating and washing device in a bath ratio of 1:25 (weight volume ratio). The fiber-separating in the present invention can be performed either by rolling and rubbing manually or in a mechanical way. The washing time was 4 h.
Finally, the raw fibers treated by fiber-separating and washing were immersed in a solution with a cellulose concentration of 10 U (International units) in a bath ratio of 1:25 (weight volume ratio) and reacted at the temperature of 55° C. for 2 h so as to perform the bio-enzyme washing.
The effluents from the waste alkali bath, fiber-separating and washing, and bio-enzyme washing were pumped into the conditioning pool for sewage treatment, and treated in the anaerobic pool, the first precipitation pool, the aerobic pool, the second precipitation pool, after which the effluents had a COD of 186, a BOD 5 of 39, a chromaticity of 12, a SS of 32, and a pH of 6.9. The effluents were returned back to the fiber-separating and washing pool for repeated use.
The degummed ramie obtained after dehydration and baking was tested for fiber quality. The results were shown in Table 1.
Example 5
The degumming processing was performed using the process flow shown in FIG. 1 and the apparatus shown in FIGS. 2-8 . The manually peeled ramie originated in Yueyang City, Hunan Province was purchased. 500 kg of the manually peeled ramie was placed into the waste alkali bath pool in a bath ratio of 1:15 (weight volume ratio) and immersed for 8 h. The solution in the pool was the alkaline wastewater discharged from the alkali-hydrogen peroxide one bath scouring-bleaching. Then, the degumming wastewater was precipitated by separate treatment, after which the resulted sludge was burnt directly and the supernatant was discharged into the sewage treatment unit.
The degumming wastewater was pumped into the sewage treatment unit, followed by the sewage treatment in the conditioning pool, the anaerobic pool, the first precipitation pool, the aerobic pool, the second precipitation pool etc.
The manually peeled ramie treated in the waste alkali bath was placed into the anaerobic washing pool in a bath ratio of 1:15 (weight volume ratio) and washed by immersion at ambient temperature for 8 h. The anaerobic washing pool was circulated with the anaerobic pool for sewage treatment, and the solution used for washing was with the same composition as that of the solution in the anaerobic pool for sewage treatment. Then, the manually peeled ramie treated in the anaerobic washing pool was placed into the aerobic washing pool in a bath ratio of 1:15 (weight volume ratio) and washed by immersion at ambient temperature for 8 h. The aerobic washing pool was circulated with the aerobic pool for sewage treatment, and the solution used for washing was with the same composition as that of the solution in the aerobic pool for sewage treatment. The aerobic washing pool was kept in the aerated state in the immersion period with the aerated dissolved oxygen of 3 to 5 mg/L.
Next, the manually peeled ramie treated in the aerobic washing pool was placed into the alkali-hydrogen peroxide one bath scouring-bleaching pool in a bath ratio of 1:15 (weight volume ratio), and immersed in a solution of 2.8 g/L NaOH and 0.5 g/L H 2 O 2 to react at the temperature of 80° C. for 2 h. The reaction liquid was discharged into the waste alkali bath pool. Then, the manually peeled ramie treated in the alkali-hydrogen peroxide one bath scouring-bleaching pool was placed into the fiber-separating and washing device in a bath ratio of 1:15 (weight volume ratio). The fiber-separating in the present invention can be performed either by rolling and rubbing manually or in a mechanical way. The washing time was 4 h.
Finally, the raw fibers treated by fiber-separating and washing were immersed in a solution with a cellulose concentration of 30 U (International units) in a bath ratio of 1:15 (weight volume ratio) and reacted at the temperature of 55° C. for 2 h so as to perform the bio-enzyme washing.
The effluents from the waste alkali bath, fiber-separating and washing, and bio-enzyme washing were pumped into the conditioning pool for sewage treatment, and treated in the anaerobic pool, the first precipitation pool, the aerobic pool, the second precipitation pool, after which the effluents had a COD of 172, a BOD 5 of 36, a chromaticity of 15, a SS of 28, and a pH of 7.2. The effluents were returned back to the fiber-separating and washing pool for repeated use.
The degummed ramie obtained after dehydration and baking was tested for fiber quality. The results were shown in Table 1.
Example 6
The degumming processing was performed using the process flow shown in FIG. 1 and the apparatus shown in FIGS. 2-8 . The manually peeled ramie originated in Ruanjiang City, Hunan Province was purchased. 500 kg of the manually peeled ramie was placed into the waste alkali bath pool in a bath ratio of 1:18 (weight volume ratio) and immersed for 8 h. The solution in the pool was the alkaline wastewater discharged from the alkali-hydrogen peroxide one bath scouring-bleaching. Then, the degumming wastewater was precipitated by separate treatment, after which the resulted sludge was burnt directly and the supernatant was discharged into the sewage treatment unit.
The degumming wastewater was pumped into the sewage treatment unit, followed by the sewage treatment in the conditioning pool, the anaerobic pool, the first precipitation pool, the aerobic pool, the second precipitation pool etc.
The manually peeled ramie treated in the waste alkali bath was placed into the anaerobic washing pool in a bath ratio of 1:18 (weight volume ratio) and washed by immersion at ambient temperature for 8 h. The anaerobic washing pool was circulated with the anaerobic pool for sewage treatment, and the solution used for washing was with the same composition as that of the solution in the anaerobic pool for sewage treatment.
Then, the manually peeled ramie treated in the anaerobic washing pool was placed into the aerobic washing pool in a bath ratio of 1:18 (weight volume ratio) and washed by immersion at ambient temperature for 8 h. The aerobic washing pool was circulated with the aerobic pool for sewage treatment, and the solution used for washing was with the same composition as that of the solution in the aerobic pool for sewage treatment. The aerobic washing pool was kept in the aerated state in the immersion period with the aerated dissolved oxygen of 3 to 5 mg/L.
Next, the manually peeled ramie treated in the aerobic washing pool was placed into the alkali-hydrogen peroxide one bath scouring-bleaching pool in a bath ratio of 1:18 (weight volume ratio), and immersed in a solution of 2.6 g/L NaOH and 0.5 g/L H 2 O 2 to react at the temperature of 80° C. for 2 h. The reaction liquid was discharged into the waste alkali bath pool. Then, the manually peeled ramie treated in the alkali-hydrogen peroxide one bath scouring-bleaching pool was placed into the fiber-separating and washing device in a bath ratio of 1:18 (weight volume ratio). The fiber-separating in the present invention can be performed either by rolling and rubbing manually or in a mechanical way. The washing time was 4 h.
Finally, the raw fibers treated by fiber-separating and washing were immersed in a solution with a cellulose concentration of 22 U (International units) in a bath ratio of 1:18 (weight volume ratio) and reacted at the temperature of 55° C. for 2 h so as to perform the bio-enzyme washing.
The effluents from the waste alkali bath, fiber-separating and washing, and bio-enzyme washing were pumped into the conditioning pool for sewage treatment, and treated in the anaerobic pool, the first precipitation pool, the aerobic pool, the second precipitation pool, after which the effluents had a COD of 182, a BOD 5 of 41, a chromaticity of 15, a SS of 35, and a pH of 7.4. The effluents were returned back to the fiber-separating and washing pool for repeated use.
The degummed ramie obtained after dehydration and baking was tested for fiber quality. The results were shown in Table 1.
TABLE 1
Degummed Ramie Fiber Quality Test Results
Single Fiber
Metric
Fiber bundle
residual gum
Fineness
Number
breaking strength
content
Measurement
dtex
Nm
CN/dtex
%
units
National
≦8.33
≧1200
≧3.50
≦5.00
standard
Example 1
5.76
1680
4.50
3.82
Example 2
5.82
1750
4.21
4.17
Example 3
5.13
1720
4.46
4.08
Example 4
5.17
1810
4.39
3.42
Example 5
5.87
1670
4.40
4.12
Example 6
5.30
1851
4.42
4.38
As can be seen from Table 1, the degumming ramie fibers obtained by the degumming method provided in the present invention had relatively good qualities. The fiber linear density, the fiber bundle breaking strength, and the residual gum content met the national standard for degummed ramie (GB/T 20793-2006).
The ramie in the above examples may also be replaced by the ramie of other origins.
In the above examples, the degumming waste liquid after fiber-separating and washing and cellulose washing was pumped into the conditioning pool, in which the degumming wastewater had a COD of 1500 to 3000 significantly lower than the COD level of 8000 to 10000 in the conditioning pool of the traditional chemical degumming wastewater treatment system. The effluent from the second precipitation pool had a COD of not higher than 200, which can meet the requirements for water used in the fiber-separating and washing of the present process. After the treatment in conventional sewage treatment system, the effluent can reach the discharge standard B of Grade 1. | The present invention relates to a chain, continuous and no-waste method for degumming and fiber-separating the ramie, including anaerobic circle step, in which the raw fibers after the waste alkali bath step are immersed in the anaerobic water pool; aerobic circle step, in which the raw fibers after the anaerobic circle step are immersed in the aerobic water pool; alkali-hydrogen peroxide one bath scouring-bleaching step, in which the raw fibers after the aerobic circle step are immersed in a combined solution of NaOH and H 2 O 2 ; and the treatment by a fiber-separating and washing device followed by the immersion in the cellulase solution. In the present invention, the ramie degumming process and the degumming wastewater treatment are performed integratively, and the degumming wastewater is completely recycled after treatment. | 3 |
BACKGROUND OF THE INVENTION
The invention relates to an electrically actuatable multiple-way valve, in particular for coolant circulation of in an internal combustion engine, having an inlet duct and at least two outlet ducts branching off from a collecting chamber, with each outlet duct per se being closable by one locking part and each locking part being connected with an electrically triggerable actuating member.
DESCRIPTION OF THE PRIOR ART
A multiple-way valve with electrically triggerable regulating members and several outlets ducts which can each be closed by a locking member is known from DE 40 33 261 A1. Multiple-way valves are usually actuated via electromagnetic regulating members. In order to exert the required closing and opening forces, the solenoids must be provided with an adequately large size. In the case of inadequate dimensioning, however, the adjusting forces to be exerted are insufficient in order to make the valve well-running again in case of jamming of the valve, e.g., as a result of corrosion after a longer standstill. In addition to the need for additional space, respectively largely dimensioned solenoid valves have the disadvantage that owing to the relatively high acceleration forces the actuation is accompanied by characteristic and disturbing noises which are not acceptable at high switching frequencies and the many paths of flows to be switched.
From DE 33 17 454 A1 a cooling system with a control unit having two thermostatic valves is known by means of which the flow cross section of two control members is controlled independently from one another.
U.S. Pat. No. 4,032,068 describes a thermostatic valve with several temperature-sensitive locking parts. Measures for electronic actuation are not provided.
The specification DE 21 11 354 A covers a swinging gate valve for coolant controllers with a thermostatic working element which is provided with a temperature-sensitive part. Measures for the electric control of the swinging gate valve are not provided.
DE 29 43 091 A1 describes a liquid cooling system for an internal combustion engine with a radiator thermostatic valve which is arranged as a rotary slide valve. The valve is provided with one inlet duct and two outlet ducts which are alternatingly opened and closed by the rotary slide valve. In one embodiment the thermostatic actuating device is provided with a heating spiral around a temperature sensor as an additional control device. The heating spiral is used to heat up the actuating device immediately after the starting process of the internal combustion engine to such an extent that the radiator thermostatic valve is actuated. It is not possible to close off each outlet duct per se by a respective locking part.
U.S. Pat. No. 4,948,043 shows a thermostatic valve with an extensible material element which contains wax as an extensible material. An electric heating is not shown.
SUMMARY OF THE INVENTION
It is the object of the present invention to avoid such disadvantages and to reduce the dimensions and the operational noises in the simplest possible way in a multiple-way valve of the kind mentioned above.
This is achieved in accordance with the invention that each electrically triggerable actuating member is provided with a temperature-sensitive, electrically-heatable extensible material element, with a cooling device preferably being provided in the zone of the extensible material element. As a result of the electric heating of the extensible material element there will be an increase of volume of the extensible material. The volume changing forces act thereby on the locking part which is preferably arranged as a rotary slide valve. It is preferably provided that the closed position of the locking part correlates with the cooled state of the extensible material element and the opened position of the locking part with the heated state of the extensible material element. This leads to the advantage that under the prerequisite of a respective dimensioning of the heating element of the actuating member a relatively rapid opening of the locking part can be effected. The closing movement of the locking part on the other hand is determined by the cooling speed of the extensible material which is generally lower than the heating speed. This benefits the requirements for the use in cooling systems in refrigerating machines in order to be able to rapidly supply the coolant in a purposeful manner and when it is needed to the parts of the machine to be cooled such as the cylinder head, the motor unit, oil heat exchanger, the turbocharger, etc. Preferably, each actuating member is in connection with an electric control device which by way of sensors determines the part to be cooled and initiates the cooling of the respective component by current supply to the heating element of the actuating member for the respective outlet duct to be triggered. In the case of sufficient cooling of the component the current supply is interrupted again, as a result of which the locking part returns relatively slowly to its closed position again in accordance with the cooling speed of the extensible material.
The closing speed is further increased by the cooling device provided in the zone of the extensible material elements.
For the purpose of further supporting the closing movement it is provided in accordance with a further, particularly preferable embodiment of the invention that the actuating member is provided with a longitudinally displaceable actuating piston which is connected with the extensible material element and is operatively connected with the locking part, with the actuating piston bordering the collecting chamber by way of a diaphragm. In this way the resetting of the extensible material element is further supported by the pressure of the coolant.
It may optionally further be provided that the actuating member is provided with a spring which supports the closing movement.
In order to save components it may be provided that the rotary slide valves are rotatably arranged on a common axle.
An embodiment in accordance with the invention is particularly preferable in which at least two outlet ducts have different diameters. In this way the coolant quantity can be adjusted to the components to be cooled respectively. Although any desired number of outlet ducts would be possible, embodiments have proved to be reliable in practical operation in which there are arranged between three and seven, preferably five outlet ducts.
Very simple manufacturing is possible if the collecting chamber is substantially provided with a cylindrical, cylinder-segment-like or prismatic shape. Favourably, the inlet duct is arranged on a face side of the collecting chamber. The inlet duct can follow directly after the outlet of a coolant pump. It is also very advantageous to arrange the coolant pump and the multiple-way valve in one unit. In order to use up as little constructional space as possible, it is further advantageous if the outlet ducts, which are preferably in a row, are arranged in the jacket zone of the collecting chamber.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is now explained in closer detail by reference to the enclosed drawings, wherein:
FIG. 1 shows an oblique view of the multiple-way valve in accordance with the invention;
FIG. 2 shows an oblique view of the multiple-way valve with a removed housing part;
FIG. 3 shows a cross section pursuant to the line III--III in FIG. 1 and
FIG. 4 shows a block diagram of a coolant circulation of an internal combustion engine with the multiple-way valve in accordance with the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The multiple-way valve 1 is provided in a housing 2 with a collecting chamber 3 into which an inlet duct 5 opens in a face side 4. In the zone of the jacket 6 of the collecting chamber 3, which is in the shape of a cylinder segment in this example, five outlet ducts 7 with partly different cross sections are arranged. A locking part 8 is provided for each outlet duct 7, with each locking part being arranged as a rotary slide valve and being rotatable per se about an axle 9 which is common for all locking parts 8, as is shown in FIGS. 2 and 3.
One actuating member 11 is provided for each locking part 8 in an actuating part 10 of the multiple-way valve 1, which actuating part is provided with an extensible material element 12 whose extensible material, preferably consisting of wax, can be heated by an electric heating element 13. The current supply to the heating element 13 is made through a socket 14. In the zone of the extensible material element 12 the actuating member 11 is provided with a cooling device 15 which consists of air- or liquid-cooled cooling surfaces. The extensible material element 12 is connected via an actuating piston 16 with a lever arm 17 of the locking part 8 which is arranged as a rotary slide valve. The extensible material element 12 is separated from the collecting chamber 3 in a liquid-tight manner by a diaphragm 18 which is penetrated by the actuating piston 16.
In the idle position in which the heating element 13 is currentless, the locking part 8 is in the closed position which is shown in FIG. 3 with the unbroken lines. Once the electric heating element 13 is charged with current, an increase in the volume of the extensible material of the extensible material element 12 occurs, as a result of which the actuating piston 16 is pressed away from the extensible material element 12 and the locking part 8 is rotated into the opened position which is indicated in FIG. 3 by the broken lines. Thus, the flow connection between the inlet duct 5 and the triggered outlet duct 7 is released. Intermediate positions are also possible, as the deflecting movement of the actuating piston 16 depends on the amount of the change in volume of the extensible material and the latter again depends on the supplied heat quantity. In this way the position of the locking part 8 can be controlled relatively easily by the amount of the supplied electric power.
The closing movement of the locking part 8 is initiated by the cooling of the extensible material in the extensible material element which can be effected by interrupting or reducing the current and/or by increasing the cooling output of the cooling device 15 for the extensible material element 12. This leads to a reduction in the volume of the extensible material and to the return movement of the actuating piston 16 to the idle position. The resetting of the actuating piston 16 is supported by the pressure of the coolant bordering the diaphragm 18. If this is insufficient, a return springs may be additionally provided for the actuating piston 16.
FIG. 4 shows an embodiment for the multiple-way valve 1 in accordance with the invention in the coolant circulation 20 of an internal combustion engine 25. The inlet duct 5 of the multiple-way valve 1 is connected to the outlet 21 of an electric water pump 22. The current supply to the sockets 14 of the actuating part 10 of the multiple-way valve 1 is performed by way of an electric pump control unit 23 which receives the values of the temperature sensors 24 in the internal combustion engine 25 as input value. The control unit 23 is further connected with an engine control unit 26, heat quantity regulator 27a and the fan 27 of the radiator 28. The reference numeral 30 indicates the vehicle heating.
The outlet ducts 7 are connected with a line 7a leading to the cylinder head, a line 7b leading to the oil cooler and, optionally, further lines 7c to the turbocharger and/or to the charge cooler or the like. A further line 7d leads to the compensator reservoir 29 of the coolant and a line 7e leads to radiator 28. In this way it is possible to individually trigger each component to be cooled by the pump control unit 23 and the coolant quantity to be discharged can be adjusted optimally to the respective requirements. | A compact, quiet, electrically actuatable multiple-way valve, in particular for coolant circulation in an internal combustion engine, includes an inlet duct and at least two outlet ducts branching off from a collecting chamber, each outlet duct being respectively closable by a locking part. Each locking part is connected with an electrically triggerable actuating member which includes a temperature-sensitive, electrically heatable extensible material element. | 5 |
[0001] This application is a continuation of patent application Ser. No. 10/820,723 filed Apr. 9, 2004.
FIELD OF THE INVENTION
[0002] The present invention relates to improvements in the field of seating devices. More particularly, the invention relates to ergonomic seating devices.
BACKGROUND OF THE INVENTION
[0003] Several attempts have been made to provide ergonomic solutions for workers which have to perform tasks in both raised and seated positions. In fact, some tasks can hardly be performed while the worker is completely seated since they require a substantial mobility from the user. Thus, over long periods of work such tasks can be very tiring for workers. Some seating devices have been developed so as to provide these workers with a further point of support in addition to their legs so as to stabilize the posture of their body, without being in a completely seated position. By using these devices a worker can thus perform tasks in a raised position and in an intermediate position so-called a sit-stand position. Some of these devices are thus called sit-stand stools or seats.
[0004] Examples of these sit-stand stools are sold by the company Steelcase™ under the name B Free™. This stool comprises a base made of a flexible material which allows a user to incline the stool at various angled positions in various directions while performing a task. The stability of the stool is maintained by means of the grip of the flexible material to the floor.
[0005] U.S. Pat. No. 4,130,263 describes a stool having a stem connected to a sand-filed base. The base comprises a flexible bag filed with sand and this base can change of shape in response to displacement of the bag produced by a tilting of the stem. However, this stool can be substantially heavy for some users in view of the amount of sand required to maintain its stability. Such a base can also be bulky and cause obstruction to a user's feet particularly when the person is not using the stool.
[0006] U.S. Published Application No. 2003/0164633 describes a sitting device comprising a seat, a stem and a floor-contacting element which acts as a base. The base has a point of apex and an outside edge which permits a user to incline or tilt the stool at various angled positions in various directions.
[0007] Some workers are however reluctant to use any one of the above-mentioned stools since they can be tilted or inclined in any directions at various angled positions and it may be difficult for a user to stabilize them. The tilting of the stem can eventually generate a lost of stability and the user can even fall down. Moreover, the grip of the base member to the floor can be reduced by dust or other impurities and can cause the stool to skid, thereby exposing a user to potential injuries. Also, since these stools can be tilted in considerably inclined positions, their use in some small workspaces such as the cashier's workspace behind a check-out counter may not be appropriate.
[0008] It is well known for ergonomists that it is sometimes difficult to convince workers to perform tasks in a different manner than the way they have been doing these tasks for many years. It is also difficult to convince them to use new tools or devices to perform these tasks. It has been demonstrated over the years that new solutions such as new methods or devices presented as alternative solutions to workers must be simple, easy to use, safe and must offer considerable advantages over the known methods or devices in order to be adopted or used by the workers. There is therefore a need to provide a seating device which would be simple, safe, easy to use and which would overcome the above mentioned drawbacks.
SUMMARY OF THE INVENTION
[0009] It is therefore an object of the present invention to provide a seating device which overcomes the above drawbacks.
[0010] It is another object of the present invention to provide a seating device which is safe and easy to use and stabilize.
[0011] It is another object of the present invention to provide a seating device which provides a plurality of positions for a user.
[0012] It is another object of the invention to provide a seating device which permits a user to carry out tasks while sitting on it, without however considerably reducing his mobility.
[0013] It is another object of the invention to provide a seating device which is light, not bulky and easily stored.
[0014] According to one aspect of the invention, there is provided a seating device comprising:
a connecting element having a end portion dimensioned to be releasably and rotatably inserted into an aperture defined in a ground or a floor, the aperture being dimensioned to receive the connecting element so as to support the seating device; and a supporting element connected to a seat, the supporting element being pivotably connected to the connecting element,
[0017] at least one of the connecting element and supporting element comprises at least one stop so as to permit the supporting element to pivot between a first position whereat the supporting element is in a substantially vertical position, and a second position whereat the supporting element is forwardly inclined of 30 degrees or less with respect to the first position.
[0018] According to another aspect of the invention, there is provided a seating device comprising:
a receiving element adapted to be fixed to a floor, the receiving element defining an internal bore; a connecting element having a end portion dimensioned to be releasably and rotatably inserted into the bore so as to support the seating device; and a supporting element connected to a seat, the supporting element being pivotably connected to the connecting element,
[0022] at least one of the connecting element and supporting element comprises at least one stop so as to permit the supporting element to pivot between a first position whereat the supporting element is in a substantially vertical position, and a second position whereat the supporting element is forwardly inclined of 30 degrees or less with respect to the first position.
[0023] According to still another aspect of the invention, there is provided a seating device comprising:
a seat; and a supporting element having
a first member connected to the seat, and a second member having an end portion dimensioned to be releasably and rotatably inserted into a floor defining an aperture dimensioned to receive the one end portion so as to stabilize the second member within the aperture,
[0028] the first and second member being pivotally connected together and the supporting element comprising at least one stop so that the first member is allowed to pivot between a first position whereat the first portion is in a substantially vertical position, and a second position whereat the first portion is forwardly inclined of 30 degrees or less with respect to the first position.
[0029] Applicants have found that by using any one of the seating devices as defined above, it is possible to provide a safe and efficient solution for persons who perform tasks in both raised and sited positions. These seating devices provide a safe support to persons who need to stabilize their posture without reducing their mobility. In fact, since these seating devices are prevented from being rearwardly inclined beyond a substantially vertical position, the risks for a user to loose stability or fall are thus reduced. Such devices permit to the user to have a good mobility since they can be rotated and forwardly inclined and allow the latter to perform various tasks while sitting on one of them. Moreover, since these seating devices are safely inserted and supported within the aperture or bore, tilting one of these devices will not cause lost of grip between the seating device and the surface or floor on which the device rests. In fact, the particular characteristics of the portion of the device inserted in the aperture, which acts as a “base”, permits to avoid the drawbacks of the seating devices of the prior art concerning their limited grip to the surface on which they rest. The “base” of the seating devices of the invention is also non bulky thereby avoiding to generate obstruction to a user's feet. The seating devices of the invention provide a further point of support to a user and thus permit him to stabilize his posture and reduce the risks of premature fatigue or discomfort. The sit-stand position adopted by a user using one of the devices of the invention thus provides stability, mobility and comfort. By using any one of these seating devices, a user reduces the stress exerted on his legs and more particularly his knees, feet and ankles.
[0030] Applicants have also found that users generally feel safe when using the seating devices of the invention since tilting is limited between the first and second positions. In particular, the users trend to be more assured by using Applicants' devices since these devices cannot be rearwardly inclined beyond a substantially vertical position.
[0031] Applicants have also found that the seating devices of the present invention are particularly useful since they can be easily removed from the aperture and stored in a small area. When a user desires to use one of these devices, it can be easily inserted into an aperture or bore and when the user wants perform tasks without the device, it can be stored as example on a shelf of a counter. The device thus permits an easy handling and storing. Therefore, a user does not have to walk and carry the device over a considerable distance before using it or simply storing it.
[0032] According to yet another aspect of the present invention there is provided in a seating device comprising a seat, a tilting stem and a base, the improvement comprising the stem being pivotally connected to the base, and at least one of the stem and the base having at least one stop so as to permit the stem to pivot between a first position whereat the pivoting portion is in a substantially vertical position, and a second position whereat the pivoting portion is forwardly inclined of 30 degrees or less with respect to the first position.
[0033] According to a further aspect of the invention, there is provided in a seating device comprising a seat, a tilting stem and a base, the improvement comprising the base being dimensioned to be inserted in an aperture defined in a floor so that the base is rotatably and releasably inserted in the aperture so as to support the seating device, the base being dimensioned to avoid generating obstruction with a user's feet.
[0034] According to still a further aspect of the invention, there is provided a method for a person to stabilize his posture comprising the steps of:
a) providing a seating device comprising a seat connected to a stem, the stem being adapted to pivot between a first position whereat the stem is in a substantially vertical position, and a second position whereat the stem is forwardly inclined of 30 degrees or less with respect to the first position; b) inserting a end portion of the stem into an aperture defined within a floor so as to stabilize the seating device; and c) sitting on the seat and selecting at least one position by inclining the stem, thereby providing a further point of support.
[0038] Applicants have found that by using such a method, a user is allowed to safely stabilize his posture thereby reducing the stress exerted on his legs. In particular, the method permits to reduce the stress exerted on the knees, ankles and feet of the user. This method also provides a safe and efficient solution for persons who perform tasks in both raised and sited positions to stabilize their posture. Such a method can also be applied by using any one of the seating devices described in the present invention.
[0039] The expression “substantially vertical position” as used herein refers to a position which can which extends at about 85 to about 95 degrees with respect to the ground or floor. Preferably, such a position extends at about 87 to about 93 degrees and more preferably at about 89 to about 91 degrees with respect to the ground or floor.
[0040] The term “floor” as used herein refers to the floor of a building or a vehicle.
[0041] The seating devices of the invention are preferably used on a floor being substantially flat. These devices are preferably stools and more preferably sit-stand stools. The seat and the supporting element are preferably coupled together so as to prevent rotation of the seat with respect to the supporting element. The end portion is preferably allowed to rotate freely within the aperture or bore according to an axis defined by the connecting element or the first member, respectively. The end portion preferably has a frusto-conical shape so as to facilitate its rotation within the aperture or bore. Preferably, the aperture or bore also has a frusto-conical shape.
[0042] When a seating device comprises a supporting element and a connecting element, a shaft can be connected to the connecting element and the supporting element can be rotatably mounted on the shaft. Preferably, the shaft is fixed to the connecting element and it comprises a threaded bolt provided with a nut. Alternatively, the supporting element and the connecting element can be pivotally connected together by means of a pivoting element. The pivoting element can be a shaft connected to the connecting element, the supporting element being mounted on the pivoting shaft. Preferably, the connecting element comprises a stop abutting a first portion of the supporting element at the first position, and abutting a second portion of the supporting element at the second position. A bias element can also be attached to the connecting element and to the supporting element so as to urge the supporting element in the first position. The seat preferably has a bottom surface or portion and the seat is preferably connected to one end of the supporting element, at the bottom surface or portion. The supporting element is preferably pivotally connected, at the other end, to the connecting element. The supporting element preferably comprises a rod connected to the seat, the rod being adjustably inserted in a stem so as to modify the length of the supporting element or the height of the seat with respect to the floor, and the stem being pivotally connected to the connecting element. Preferably, the supporting element comprises a pneumatic device so as to modify the length of the supporting element or the height of the seat with respect to the floor. In the second position, the supporting element is preferably inclined of 25 degrees or less, and more preferably of 20 degrees or less, with respect to the first position.
[0043] When a seating device comprises a supporting element having a first and a second member, the latter two members are preferably pivotally connected together by a shaft which is connected to the second member. The first member is pivotally mounted on the shaft. Preferably, the shaft is fixed to the second member and it comprises a threaded bolt provided with a nut. Alternatively, the first and second members can be pivotally connected together by means of a pivoting element. The pivoting element can be a shaft connected to the second member, the first member being mounted on the pivoting shaft. Preferably, at least one of the first and second members comprises a stop abutting a first portion of the supporting element at the first position, and abutting a second portion of the supporting element at the second position. A bias element can also be attached to the first and second members so as to urge the first member in the first position. The seat preferably has a bottom surface or portion and the seat is preferably connected to one end of the first member, at the bottom surface or portion. The first member is preferably pivotally connected, at the other end, to the second member. The first member preferably comprises a rod connected to the seat, the rod being adjustably inserted in a stem so as to modify the length of the supporting element or the height of the seat with respect to the floor, and the stem being pivotally connected to the connecting element. Preferably, the first member comprises a pneumatic device so as to modify the length of the supporting element or the height of the seat with respect to the floor. In the second position, the first member is preferably inclined of 25 degrees or less, and more preferably of 20 degrees or less, with respect to the first position.
[0044] When a seating device also comprises a receiving element, the latter preferably includes a first portion defining the internal bore. This first portion is adapted to be inserted in an aperture defined within the floor. The receiving element also includes a second portion connected to the first portion, the second portion being secured to the floor. The second portion is preferably dimensioned in order to avoid generating obstruction to a user's foot. The second portion can extend above the floor from less than 1 cm, and preferably form less than 0.30 cm.
[0045] The seating devices of the invention can further comprise an adjustment element for holding the supporting element in a selected inclined position so as to permit to a user to maintain the selected position without contacting the seating device. Advantageously, the seating devices comprise an adjustment element for modifying the tilt of the seat. The seat can also comprise a top surface having a periphery and a raised portion adjacent to the periphery. The raised portion is adapted to be grasped by at least one of the buttock muscles and ischial tuberosities of a user. Such a raised portion thus permits to reduce risks of sliding. It can also permit to the user to sit on the seat without use of his hands. The seating devices of the invention advantageously have a predetermined size so that they can be stored on a shelf below the top surface of a counter such as check-out counter as found in supermarkets or any retail stores. The seating devices of the invention can also comprise a footstool having an inclined surface for receiving user's feet, the surface being inclined in such a manner that a user's feet are upwardly extending. The footstool is advantageously disposed in proximity with the aperture or bore.
[0046] The preferred embodiments described above in respect of the seating devices according to the invention can also be applied to the method of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0047] Further features and advantages of the invention will become more readily apparent from the following description of preferred embodiments as illustrated by way of examples in the appended drawings wherein:
[0048] FIG. 1 is a rear perspective view of a seating device according to a preferred embodiment of the invention;
[0049] FIG. 2 is a rear perspective view of a seating device according to another preferred embodiment of the invention;
[0050] FIG. 3 is a side elevation view of the seating device shown in FIG. 2 , wherein different positions of the seating device are shown;
[0051] FIG. 4 is a side elevation view, partly fragmented, of the seating device shown in FIG. 3 , wherein the seating device is shown in an inclined position;
[0052] FIG. 5 is a rear elevation view of the device shown in FIG. 2 ;
[0053] FIG. 6 is a side elevation view of the seating device shown in FIG. 2 , wherein the seating device is inserted in an aperture defined in a floor;
[0054] FIG. 7 is a side elevation view of the seating device shown in FIG. 2 , wherein the seating device is inserted in a receiving element according to another preferred embodiment of the invention;
[0055] FIG. 8 is a rear perspective view of a seating device according to another preferred embodiment of the invention;
[0056] FIG. 9 is a rear perspective view of a seating device according to another preferred embodiment of the invention,
[0057] FIG. 10 is a side elevation view of a seating device shown in FIG. 9 , wherein the device is also shown as stored on a shelf.
DESCRIPTION OF PREFERRED EMBODIMENTS
[0058] Referring first to FIGS. 1 and 2 , there is shown a seating device 10 or 11 comprising a connecting element 12 , a supporting element 14 and a seat 16 . Seating devices 10 and 11 are similar, with the exception that the seating device 11 further comprises few adjustment elements. The connecting element 12 is pivotally connected to the supporting element 14 . In fact, the supporting element 14 is mounted on a bolt 18 provided with a washer 20 and a nut 21 . The connecting element 12 and the supporting element 14 both define apertures through which the bolt 18 is inserted and then inserted in the washer 20 and the nut 21 , thereby pivotally connecting the latter two elements. The supporting element 14 and the connecting element 12 can also be pivotally connected by several other manners such as a shaft provided with rivets, a hinge or any means known to the person skilled in the art so as to pivotally connect the two elements together.
[0059] The connecting element 12 has an end portion 22 having a frusto-conical shape and which is adapted to be inserted in an aperture defined in a floor so as to support the seating device 10 or 11 . The connecting element 12 also comprises a stop 24 which abuts a first portion 26 of the supporting element 14 in a raised or first position and a second portion 28 of the supporting element 14 in an inclined or second position (FIGS. 1 to 4 ). The stop 24 thus permits the supporting element 14 to pivot between a first position where it extends substantially vertically and a second position where it is inclined according to the angle α ( FIG. 3 ). The angle α has a value of about 30 degrees or less, preferably about 25 degrees or less and more preferably about 20 degrees or less. The stop 24 thus prevents the supporting element 14 from being tilted or inclined rearwardly beyond a substantially vertical position, and forwardly beyond the second position. Alternatively, a stop can be disposed on said supporting element as it can be seen from FIG. 4 , both portion 28 and stop 24 comprise a recessed or rounded portion so as to permit the supporting element 14 to be forwardly inclined. The connecting element 12 and the supporting element 14 are also connected together by a bias element such as a bias spring 30 which urges the supporting element 14 in the raised or first position.
[0060] Thus, when a user is sitting on the seating device 10 or 11 stands up and leaves his sitting position, the supporting element 14 will automatically pivot from an inclined position to the raised or first position. Optionally, the nut 21 can be adjusted in such a manner to increase the friction between element 12 and 14 so that the spring 30 will not be sufficient to urge the inclined supporting element 14 in the first portion. Thus, such an adjustment will permit to the user to maintain a selected inclined position even without holding or contacting the device. Such an option can be particularly useful if the user quits his sitting position for few moments and he then wants to quickly adopt again the same sitting position without being obligated to adjust the device one more time so as to select this particular position. From these explanations, it will be understood by the person skilled in the art that other adjustment elements can be provided in replacement of the nut 21 , and which will be more easily adjusted by the user.
[0061] As shown in FIG. 1 , the seat 16 comprises a seat panel 32 secured to the supporting element 14 , and a seating portion 34 . The seating portion 34 preferably comprises a cushion. The seating portion 34 further comprises a lip or raised portion 36 which permits the user to easily grab the seat with his buttocks muscles and/or with his ischial tuberosities without using his hands. Moreover, such a raised portion reduces the risks for the user to loose grip and slide when contacting the seating portion with his muscles and/or ischial tuberosities.
[0062] As shown in FIGS. 2, 3 and 5 to 7 , the seat 16 can be connected to the supporting element 14 by means of a coupling element 37 having a parallelepiped shape so as to prevent the rotation of the seat 16 with respect to the supporting element 14 . The seat 16 can further comprises adjustment devices. A top portion 38 including the seating portion 34 having a lip 36 and the seat panel 32 is connected to a bottom portion 40 by means of an adjustment element 42 . The seat panel 32 is connected to the bottom portion 38 by means of the adjustment element 42 which comprises a threaded rod 44 inserted in a screw nut 46 . The top portion 38 can thus be inclined with respect to the bottom portion 42 by adjusting the screw nut 46 . It has been found that by using such an adjustment element, it is possible to limit the space required for the operating radius of the device in view of the tilt of the seat 16 . The seating device 11 also comprises an actuating lever 48 coupled with a pneumatic device such as a pneumatic compression spring assembly i.e. a telescoping cylinder-piston assembly (not shown) which permits to adjust the length of the supporting element 14 (or the height of the seat 16 with respect to the floor). The pneumatic device can be as example a pneumatic compression spring assembly is one as usually used in the manufacture of chair or the like and it comprises a slidable piston attached to a piston rod which is inserted in the supported member 14 acting as a housing.
[0063] Alternatively, the supporting element can comprises a rod connected to the seat and slidably inserted in a housing comprising a clamping device so as to adjust the length of the supporting element. Such an adjustable supporting element is described in U.S. Pat. No. 4,130,263, which is hereby incorporated by reference. Moreover, the supporting element can comprise a housing having an interior threaded section in which a spindle is inserted, the spindle being connected to the seat. Such an adjustable supporting element is described in U.S. Pat. No. 6,644,742, which is hereby incorporated by reference.
[0064] FIG. 6 shows the seating device 11 which has been inserted in an aperture defined in a floor 52 , the aperture being dimensioned to receive the connecting element 12 . The floor 52 is preferably a floor comprising a resistant material such a metal or concrete.
[0065] FIG. 7 shows the seating device 11 inserted in a receiving element 49 comprising an internal bore (not shown) adapted to receive the portion 22 of the connecting element 12 . The internal bore can also be provided with Teflon® so as to facilitate rotation of the portion 22 , thereby reducing friction. The receiving element 49 also has a flat portion 50 contacting the floor 52 . The flat portion 50 defines apertures (not shown) in which fasteners 54 such as screws or bolts are inserted so as to secure the receiving element 50 to the floor. Such a flat portion and fasteners are preferably as thin as possible so as to prevent generating obstruction to a user's foot. Thus, when the device is stored, the presence of the receiving element 49 does not cause any inconvenience to a person walking on the floor. Optionally, the hole defined by the internal bore can be covered by a cap when the device is not inserted therein.
[0066] As shown in FIGS. 8 to 10 the seating devices of the present invention can be particularly useful for a person 53 working as a cashier for example. Usually such workers perform tasks which necessitate a certain mobility. In particular, these persons manipulates purchased articles on a check-out counter 55 having a top surface 56 and a shelf 58 , as well as perform tasks with a cash register 60 . Over extended period of times such tasks requiring several displacements can be very tiring since the persons usually stands up. When using one of the devices of the present invention the user can thus stabilize his posture has shown in FIGS. 8 to 10 while maintaining a good mobility since these devices can be rotated and forwardly inclined.
[0067] As shown in FIG. 10 , the seating device 11 is not bulky and can easily be stored on the shelf 58 . Preferably, the seating device 11 has a weight of 3.75 kg or less and more preferably of 2.25 kg or less. When the person wants to use the device, the latter just needs take it from the shelf 58 and insert the end portion 22 (FIGS. 2 to 4 ) into the bore defined in the receiving element 49 (FIGS. 7 to 10 ) so as to support the seating device 11 . Then, the person can grab the raised portion 36 ( FIGS. 2 and 3 ) with his buttock muscles and/or ischial tuberosities so as to sit on the seat 16 . Before or while sitting on the seat 16 , the person can adjust the tilt of the seat 16 with the adjustment element 42 . The person can also adjust the height of the seat 16 with respect to the floor 52 , by means of the lever 48 .
[0068] The person thus sitting or being supported by the device in a sit-stand position can rotate the latter or tilt it so as to perform his tasks. If the person quits the device, the spring 30 ( FIGS. 3 and 4 ) will urge the seating device in the first position. Optionally, the nut 21 (FIGS. 1 to 4 ) can be adjusted so as to hold the device in a particular inclined position. When the person wants to store the seating device 11 , the latter simply has to remove the device from the receiving element 49 and store it on the shelf 58 .
[0069] As shown in FIG. 8 , the person 53 adopting a sit-stand position is provided with supplemental point of supports since he is sitting on the seating device 11 and his hands are abutting the top surface 56 . For extra stability and comfort, the device of the invention can be provided with a footstool 62 ( FIGS. 9 and 10 ) having an inclined surface so as to permit to the person 53 to reduce the stress exerted on his feet, knees and ankles. The slope of the footstool 62 is preferably of about 15 to about 25 and preferably about 20 degrees. The top surface of the footstool 62 can be advantageously provided with a non-slip material like a polymeric material or a rubber-like material.
[0070] The seating device and method of the present invention can be used by different workers in different job environments. As examples they can be used by cashiers and clerks in retail stores, supermarkets and banks. They can also be used by persons working in laboratories or workers in a plant. The seating device and method of the present invention can be used for practicing various types of hobbies such as fishing and hunting. As example, such a device can be inserted in the floor of a boat thereby providing a supplemental point of support to a fisher while permitting him to have a good mobility. The device can also be used as an alternative to the traditional stools used by musicians such as guitar players. It can further be used by percussionists.
[0071] While the invention has been described with particular reference to the illustrated embodiment, it will be understood that numerous modifications thereto will appear to those skilled in the art. Accordingly, the above description and accompanying drawings should be taken as illustrative of the invention and not in a limiting sense. | A seating device comprising a connecting element having an end portion dimensioned to be releasably and rotatably inserted into an aperture defined in a ground or floor. The aperture is dimensioned to receive the connecting element so as to support the seating device. The seating device also comprises a supporting element connected to a seat. The supporting element is pivotably connected to the connecting element. Moreover, at least one of the connecting element and supporting element comprises at least one stop so as to permit the supporting element to pivot between a first position whereat the supporting element is in a substantially vertical position, and a second position whereat the supporting element is forwardly inclined of 30 degrees or less with respect to the first position. Such a device is particularly useful for persons who need to stabilize their posture while performing a task. | 0 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is based upon and claims the benefit of priority of U.S. Provisional Application Ser. No. 62/170,786, filed Jun. 4, 2015, the entire contents of which are incorporated herein by reference.
BACKGROUND
[0002] 1. Field
[0003] This invention relates to the hot mix asphalt plant used to manufacture asphaltic mixes to pave highways.
[0004] 2. Description of the Related Art
[0005] The components of the state of the art hot mix asphalt plant combine process methods to heat and dry aggregates, add coarse and fine aggregate dust particles and mix them with asphalt. The raw material virgin aggregates release dust particles as they are heated and dried that must be collected using mechanical separation for the coarse dust particles along with fine dust collection using fabric filters or baghouses to eliminate air borne particulate from entering the atmosphere. Asphalt plants use rotary dryers to tumble the aggregates in the presence of heat to remove the moisture and heat them to the process temperature.
[0006] Drying aggregates with the rotary dryer involves a physical separation process designed for the purpose to remove the liquid phase or moisture using thermal energy. The liquid in this case is water that is liberated by the process of vaporization leaving a solid or aggregates with a trace of residual moisture. The dryer is a direct heat dryer as heat transfer for drying is accomplished by direct contact between the wet solid aggregate with hot gases from a combustion burner. This invention describes the dryer as a rotating cylindrical shell, slightly inclined to the horizontal with the heating medium flowing in a countercurrent direction to the flow of aggregates through the dryer. The dryer is equipped with flights or lifters on the interior for lifting and moving the wet aggregates through the hot gas stream as they pass through the cylinder.
[0007] As the gases pass through the dryer the aggregates become hot and dry thus liberating aggregate dusts that cling to the aggregates. Some aggregates liberate dust as they are tumbled through the rotary dryer. The dryer operates under a suction pressure as the dust particles are pulled through the dryer and into the coarse particle mechanical dust separation devices and finally into the fabric filters for dust collection. Those dust particles must pass from the rotary dryer to the dust collection devices generally using ductwork or large round pipes or rectangular ducts to move the moisture, products of combustion and dust to the dust collection devices. This industrial size external ductwork usually requires the use of a large lifting crane to assemble the ductwork from the rotary dryer to the dust collection devices and filter house needed to collect the hot dry aggregate particles. Moving the asphalt plant from one location to another becomes cumbersome as lifting equipment is needed to assemble and disassemble the plant rotary dryer from the dust collection equipment.
[0008] Making asphaltic mixes requires a recipe using a combination of sand and varying sizes of aggregates. Multiple bins are needed to contain the sand and aggregates. The bins are filled using construction bucket loading tractors from the site stored aggregates piles.
[0009] The aggregate bins are each fitted with an underlying variable speed belt feeder that proportions the needed flow of raw material to combine the hot mix recipe.
[0010] The raw aggregates are generally conveyed with a belt collection conveyor to a large vibrating screen to insure debris or oversize materials are eliminated from the flow of aggregates to insure a smooth road surface. A vibrating screen device of the size needed on the asphalt plant generally must be conveyed as a separate unit and mounted to a large wheeled trailer assembly in order for it to be conveyed for the portable plant. Bins of this size and capacity normally require a large individual wheeled trailer assembly as they are moved as a separate component of the portable asphalt plant. The movement of aggregates from the aggregate bins and oversize vibrating screen requires the use of a long portable conveyor belt assembly to move the aggregates to the rotary dryer for processing. These portable conveyors are fitted with truck axles and wheels as they are moved along with the portable asphalt plant.
[0011] The dust particle size separation and collection equipment needed on the portable plant is generally conveyed as a separate component with truck axles and wheels that also must be positioned on the plant site to mount the large connecting duct pieces between the rotary dryer and dust separation equipment. The large portable rotary dryers as well are conveyed as a separate component with truck axles. Ductwork connection and feed conveying plant components must be connected to the rotary dryer once it is in place at the portable plant site.
[0012] Once the hot mix asphalt is produced it must be conveyed away from the rotary dryer, stored and weighed and then transferred to a dump truck to be carried to the road paving site. Each of these devices must be made portable and carried along with the other plant components as a separate piece of equipment with truck axles as trailer assemblies.
[0013] Each time a portable hot mix asphalt plant is moved, each site must be graded, leveled and compacted to insure the proper soil surface conditions exist to allow the equipment to be assembled and parked for alignment and safety. As described, the portable hot mix asphalt plant can easily contain ten individual plant components. Transporting and preparing the site represents time taken away from actual plant production; the cost to prepare the site, grading for each piece of equipment and the cost of additional site preparation materials such as soil and aggregates to prepare and level the site.
SUMMARY
[0014] As can be derived from the aforementioned description of a typical portable hot mix plant, there is a significant advantage for a highly portable plant that can be manufactured with fewer major components and can be erected and operational faster than a typical plant. Such a plant would be designed so as to not require lifting cranes to erect the plant; require fewer transport truck loads; have a smaller geographical footprint; and can be quickly erected and assembled thus saving time, energy and financial burden.
[0015] In one aspect, a highly portable asphalt plant of substantial size and product manufacturing capacity carries the system components on the confines of two transportable vehicles. The two vehicles are arranged in a fashion whereby vehicle one is connected to vehicle two in an inline continuous fashion. Vehicle two contains an integrated inertial dust separator baghouse design and provides for the receiving of the rotary dryer drum mixer directly and without the use, of interconnecting ductwork.
[0016] In another aspect, a transportable hot mix asphalt plant apparatus includes a first vehicle having an aggregate collector conveyor, at least one aggregate storage bin disposed above the aggregate collector conveyor, at least one aggregate storage bin equipped with a variable speed aggregate feeder belt discharging onto a vibrating screen, the aggregate collector conveyor having a collector belt weigh scale disposed at an output end, the output end discharging onto an aggregate collector belt extension, and a second vehicle having a counter-flow aggregate rotary dryer and mixer, the counterflow aggregate rotary dryer and mixer receiving aggregate from a discharge end of the aggregate collector belt extension, a hot mix asphalt elevating drag slat conveyor to convey asphalt mix to a storage hopper, a self-erecting frame for the hot mix asphalt elevating drag slat conveyor, and a support stand for the storage hopper.
[0017] In another aspect, a transportable hot mix asphalt plant carries a plurality of major components on a first and a second vehicles for transport within guide lines of typical road transportation limits.
[0018] In another aspect, a transportable hot mix asphalt plant apparatus assembles a first and a second vehicles at a job site without a need of inter-connecting ductwork between a rotary dryer and a dust collection device.
[0019] In another aspect, a transportable hot mix asphalt plant apparatus erects an apparatus in a field without a need of auxiliary lifting devices or lifting cranes.
[0020] In another aspect, a transportable hot mix asphalt plant apparatus connects a rotary dryer to an inlet of a primary collector, and connects a primary collector directly to a filter baghouse without inter-connecting ductwork.
[0021] In another aspect, a transportable hot mix asphalt plant allows dust laden exhaust gases from a rotary dryer to be directed to an inlet of a primary collector without inter-connecting ductwork.
[0022] In another aspect, a transportable hot mix asphalt plant apparatus includes a floating seal assembly located on a rotary dryer for direct connection to a primary collection box on a baghouse without external inter-connecting ductwork.
[0023] In another aspect, a transportable hot mix asphalt plant apparatus includes a small dynamic in-motion scalping screen disposed on a at least one aggregate storage bin.
[0024] In another aspect, a transportable hot mix asphalt plant apparatus includes a plurality of aggregate storage bins, each of the plurality of aggregate storage bins having a small dynamic in-motion scalping screen in place of one large dynamic scalping screen for a plurality of aggregate storage bins.
[0025] In another aspect, a transportable hot mix asphalt plant apparatus includes a unique counter-flow baghouse design that does not require a use of an air compressor to pulse clean dust filter bags.
[0026] In another aspect, a transportable hot mix asphalt plant apparatus includes a unique portable counter-flow baghouse that incorporates an integral coarse dust inertial separator—primary dust collector.
[0027] In another aspect, a transportable hot mix asphalt plant apparatus includes a combination portable counter-flow baghouse—inertial dust collector that includes screw augers to remove dust from a baghouse and a cross auger assembly to collect a dust from an inertial dust collector.
[0028] In another aspect, a transportable hot mix asphalt plant apparatus includes a unique portable baghouse and inertial dust collector assembly that incorporates a collecting dust system of screw augers for fine and coarse dust collection in one assembly.
[0029] In another aspect, a transportable hot mix asphalt plant apparatus includes a unique portable baghouse dust collector design assembly that provides for acceptance of a rotary dryer directly to an inertial dust collector assembly.
[0030] In another aspect, a transportable hot mix asphalt plant apparatus includes a unique portable baghouse and inertial dust collector assembly that includes a complete dust removal system to collect both fine and coarse dust particles.
[0031] In another aspect, a transportable hot mix asphalt plant apparatus includes a combination portable counter-flow baghouse—inertial dust collector assembly that includes a pneumatic dust transport system from a baghouse to a mixing zone of a counter-flow aggregate rotary dryer and mixer in which hot liquid asphalt is combined with aggregates.
[0032] In another aspect, a transportable hot mix asphalt plant apparatus includes a portable counter-flow baghouse with a multiple pocket, elliptical design filter for increased filter media surface area in a smaller geographical footprint.
[0033] In another aspect, a transportable hot mix asphalt plant apparatus includes a unitized transportable vehicle assembly that contains at least one aggregate storage bin, conveyor belt feeders, scalping screen for each feeder, aggregate collector conveyor, collector belt weigh scale, aggregate collector belt extension to move aggregates to a rotary dryer, coarse dust primary collector, fine dust baghouse filter, baghouse exhauster fan, exhauster fan damper, system exhaust stack, baghouse dust hopper screw augers, dust collection cross auger, wheeled truck axles for portability, and trailer connection pin to connect transport truck tractor with unitary frame design for transport.
[0034] In another aspect, a unitized transportable vehicle assembly contains a counter-flow aggregate rotary dryer and mixer, a hot mix asphalt elevating drag slat conveyor, a self-erecting frame, a support stand for a storage hopper, an asphalt injection system, a combustion burner, rotary dryer drive components, wheeled truck axles for portability, and a trailer connection pin to connect transport truck tractor with a unitary frame design for transport.
[0035] The above and other features and advantages of the present invention, as well as the structure and operation of various embodiments of the present invention, are described in detail below with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0036] The accompanying drawings, which are incorporated herein and form part of the specification, illustrate various embodiments of the present invention and, together with the description, further serve to explain the principles of the invention and to enable a person skilled in the pertinent art to make and use the invention. In the drawings, like reference numbers indicate identical or functionally similar elements. A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:
[0037] FIG. 1 shows a first vehicle in transport mode according to an embodiment;
[0038] FIG. 2 shows a second vehicle in transport mode according to the embodiment;
[0039] FIG. 3 shows a silo of the second vehicle being erected;
[0040] FIG. 4 shows the silo of the second vehicle being erected;
[0041] FIG. 5 shows a baghouse for the second vehicle;
[0042] FIG. 6 shows the first and the second vehicles in an installed condition;
[0043] FIG. 7 shows the collector belt weigh scale device;
[0044] FIG. 8 shows the first vehicle mated to the second vehicle; and
[0045] FIG. 9 shows the first vehicle and the second vehicle in operation.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0046] In FIG. 1 is shown a first vehicle 100 in transport mode according to an embodiment. The first vehicle 100 includes up to four virgin aggregate feed bins 102 of substantial size that can be charged with virgin aggregates using large wheeled loader tractors. Each of the aggregate feed bins 102 is equipped with a variable speed aggregate feeder belt 104 used to accurately control the flow of varying sizes of aggregates and sand to manufacture hot mix asphalt of any specification.
[0047] Each of the aggregate feeder belts 104 discharges onto a vibrating screen 106 used to screen out any over size aggregates, rocks or debris. The debris is directed over the side of the feed assembly away from the equipment. The vibrating screens 106 are sized to accommodate the flow of aggregates from only one feed bin feeder allowing the use of a smaller size screening unit.
[0048] The screened aggregates are then directed onto a collection conveyor belt 108 . The collection conveyor belt 108 moves under each of the aggregate feed bins 102 collecting the portions of aggregate from each feeder. As the collection conveyor belt 108 progresses forward, it passes over a collector belt weigh scale device 110 that develops an electrical output signal used by the control system to measure the total flow of aggregates across the collector belt weigh scale device 110 to accurately weigh the plurality of aggregates as they progress toward the rotary dryer 202 (shown in FIG. 2 ). To save space the collection conveyor belt 108 progresses under the primary and secondary dust collection devices or baghouse.
[0049] In FIG. 5 is shown a baghouse 500 according to an embodiment of the invention. The collection conveyor belt 108 is enclosed into a rectangular housing as it is elevated in height and passes up and through the baghouse 500 and primary collector. Aggregates carried on the belt are deposited into the rotary dryer 202 located on the second vehicle 200 , which is shown in FIG. 2 . The dust laden gases exiting the rotary dryer 202 on the second vehicle 200 enter the primary collector where the heavier dust particles are separated as the gases continue and move into the baghouse where the finest of aggregate particulate are collected.
[0050] The floor of the baghouse 500 is separated into two dust collection, v-shaped hoppers 502 on the left and right side. Each of the hopper sections 502 encloses a screw auger conveyor 504 to move the dust from one end of the baghouse 500 forward and into a cross auger assembly 506 perpendicular to the baghouse hopper augers 504 . The cross auger assembly 506 then carries all of the coarse and fine dust particles to one side of the baghouse 500 and discharges the dust to a rotary airlock feeder 508 . The rotary air lock feeder 508 stops air and dust back flow from re-entering the baghouse dust augers, and allows the dust to be blown to the end of the rotary dryer 202 on the second vehicle 200 into the mixing zone of the drum mixer dryer. This rotary airlock feeder 508 transfers the dust to an air eductor device on the dust line that is under positive air pressure from a motor driven dust blower.
[0051] In FIG. 8 is shown a floating seal assembly 802 located on the rotary dryer for direct connection to a primary collection box on a baghouse without interconnecting ductwork. This floating seal assembly 802 allows the dust laden exhaust gases from the rotary dryer to be directed to the air Inlet of the primary collector. The floating seal assembly 802 prevents dust laden gases from escaping to the atmosphere.
[0052] The counter-flow dust collection baghouse 500 operates at low differential air pressure across the body of the baghouse 500 . Lower differential air pressure requires less fan horsepower which is the advantage to this operational design. The counter-flow self-cleaning baghouse 500 does not use compressed air to pulse clean the bag filter elements. Therefore, an air compressor is not required to supply the motive force to clean the filter bags which is an additional advantage in using the counter flow baghouse design. In addition, an air compressor is not required for the plant components nor is electrical power or air piping. This is an additional advantage to the counter-flow baghouse.
[0053] In total, the first vehicle 100 contains the aggregate storage bins 102 , conveyor belt feeders, scalping screen for each feeder, aggregate collector conveyor 108 , collector belt weigh scale device 110 , aggregate collector belt extension to move the aggregates to the rotary dryer 202 , coarse dust primary collector, fine dust baghouse filter collector, baghouse exhauster fan, automatic exhauster fan damper, system exhaust stack, (2) baghouse dust hopper screw augers, dust collection cross auger, wheeled truck axles for portability, and trailer connection pin to connect transport truck tractor with unitary frame design.
[0054] In FIG. 2 is shown a second vehicle 200 in transport mode according to an embodiment. The rotary dryer 202 is located on the second vehicle 200 . Aggregates from the first vehicle 100 are fed into the feed end of the rotary dryer 202 from the collection conveyor belt 108 elevating extension 112 (shown in FIG. 1 ). The aggregates start at the dryer exhaust gas end of the rotary dryer 202 and slowly move forward into the counter-flow dryer drum 204 . The counter-flow dryer drum 204 is positioned at a downward angle to allow the cascading aggregates inside the rotary dryer 202 to advance toward the discharge end of the rotary dryer 202 as it rotates. Once the aggregates are hot and dry they advance into the mixing portion of the drum mixer 206 where dust, additives and liquid hot asphalt are injected to formulate the hot mix asphalt.
[0055] The rotary dryer 202 is heated using a combustion burner that mounts inside the support structure in the mixing portion of the counter-flow dryer drum 204 . The combustion burner supplies the heat necessary to the aggregates in the rotary dryer 202 . The firing end of the burner extends into the discharge end of the rotary dryer 202 beyond the mix section so as not to overheat the aggregates and liquid asphalt as they are mixed together in the mixing zone of the dryer prior to being discharged as final product.
[0056] The final hot mix asphalt flows from the discharge of the rotary dryer 202 into a drag slat elevating conveyor 208 . The final hot mix asphalt moves to an elevation to allow it to flow into a storage hopper 210 . A dump truck is positioned under the storage hopper 210 and the final hot mix asphalt is dispensed into the dump truck. The truck moves away and the process continues as another truck moves into position to receive hot mix asphalt from the hopper above.
[0057] The trailer 212 under the rotary dryer 202 is equipped with truck axles 214 for transport by a tractor trailer. The drag slat elevating conveyor 208 is mounted on a pivot pin connection that allows the unit to be elevated when the plant is set for operation. As the plant is prepared for moving, the drag slat elevating conveyor 208 is lowered. In the transport position, the drag slat elevating conveyor 208 is reduced in height to meet typical road transport height requirements. The drag slat elevating conveyor 208 lowers on its pivot connection to travel with the second vehicle 200 fully assembled and is not removed for transport. The storage hopper 210 is part of the drag slat elevating conveyor 208 assembly which folds over to allow transport on the same vehicle assembly.
[0058] In total, the second vehicle 200 contains the counter-flow aggregate rotary dryer 202 and mixer combination, asphalt injection system, combustion burner, rotary dryer 202 drive components, wheeled truck axles 214 for portability, trailer connection pin 218 to connect the transport truck tractor 220 with unitary frame, self-erecting trailer frame 216 to be used in the transport position, hot mix asphalt drag slat elevating conveyor 208 to convey asphalt mix to the storage hopper for delivery into trucks and the support stand for the storage hopper. All of these devices are stored on the trailer assembly in the transport position and are transported as a single unit.
[0059] In FIG. 3 is shown the silo of the second vehicle 200 being erected. The trailer support legs 302 are down, while the cylinders 304 that will raise the drag slat elevating conveyor 208 , the storage hopper 210 , and the vertical self-erecting legs 216 are shown being extended in FIG. 3 . The support legs 306 are still stowed.
[0060] In FIG. 4 is shown the silo of the second vehicle 200 being erected. The cylinders 304 that will raise the drag slat elevating conveyor 208 , the storage hopper 210 , and the vertical self-erecting legs 216 are shown being extended in FIG. 4 . The support legs 306 are swinging into position.
[0061] The major plant components are contained within two main trailer vehicles, as shown in FIG. 9 . Both vehicles 100 and 200 are backed into each other using a transport truck tractor, as shown in FIG. 6 . The plant operates as follows:
[0062] Each of the aggregate storage bins 102 are charged or filled with aggregate needed to meet the needs of the hot mix asphalt design.
[0063] The conveyor belt feeders under each of the bins 102 is electrically turned on. The speed of the feeder belts 104 are varied so as to control the needed percentage of each raw material component required for the hot mix asphalt design.
[0064] Each of the conveyor belt feeders discharges the aggregates over each of the small, electrically operated vibrating scalping screens 106 located at the end of the feeder belts 104 . Any oversize aggregates or debris is discarded off to the side to insure the integrity of the raw material mix design.
[0065] The select aggregates discharge onto a centrally located belt conveyor or collection conveyor belt 108 that is in motion under the aggregate bins 102 and feeders. The collection conveyor belt 108 travels under the aggregate bins 102 and longitudinally conveys the aggregates under and through the baghouse and up and into the rotary dryer 202 .
[0066] A conveyor belt weigh scale device 110 is mounted on the collection conveyor belt 108 downstream of the aggregate bins 102 to electrically measure the flow of aggregates on the collection conveyor belt 108 , as shown in FIG. 7 .
[0067] The flow of exhaust gases from the rotary dryer 202 pass through the primary coarse dust collector prior to flowing into the fine particle baghouse filter collection assembly. Those coarse dust particles fall into a hopper and are directed to the baghouse dust collection auger.
[0068] The fine particle collection baghouse collects and disperses internally the dust into two hopper mounted dust screw auger assemblies driven by electric motors. The screw augers convey the dust from the baghouse to the dust cross auger assembly mounted perpendicular to the back side of the baghouse.
[0069] Coarse dust from the primary collector and fine dust from the baghouse is collected onto the baghouse cross auger. Dust is then delivered to a rotary valve feeder and airlock to convey the dust under negative suction pressure from the baghouse. The rotary valve directs the dust to an eductor assembly attached to a pressure blower. The pressure pneumatically forces the dust through a dust pipe and directs the dust into the mixing section of the rotary dryer 202 . The dust is combined with liquid asphalt and aggregates to produce the end product hot mix asphalt design.
[0070] The rotary dryer 202 located on the second vehicle 200 receives the raw aggregates from the aggregate collection conveyor on the first vehicle 100 . Aggregates pass from the feed end of the dryer and are heated and dried to remove internal moisture. Next, the aggregates are mixed with liquid asphalt and dust conveyed from the baghouse to produce the final hot mix asphalt design.
[0071] The hot mix asphalt is directed from the discharge end of the rotary drum mixer into a drag slat elevating conveyor 208 . The hot mix asphalt is conveyed to an elevation above the hot storage hopper 210 . The drag slat elevating conveyor 208 is driven by an electric motor continually moving hot mix asphalt in incremental amounts between the slats of the conveyor chain. The asphalt falls off the discharge end of the conveyor into the storage hopper 210 .
[0072] The interim storage hopper 210 is held in place by the drag slat elevating conveyor 208 of one side and vertical self-erecting legs 216 on the opposite side of the assembly to support the weight of the hopper 210 and hot mix asphalt delivered into the hopper 210 .
[0073] The foregoing has described the principles, embodiments, and modes of operation of the present invention. However, the invention should not be construed as being limited to the particular embodiments described above, as they should be regarded as being illustrative and not restrictive. It should be appreciated that variations may be made in those embodiments by those skilled in the art without departing from the scope of the present invention.
[0074] While a preferred embodiment of the present invention has been described above, it should be understood that it has been presented by way of example only, and not limitation. Thus, the breadth and scope of the present invention should not be limited by the above described exemplary embodiment.
[0075] Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that the invention may be practiced otherwise than as specifically described herein. | A highly portable asphalt plant of substantial size and product manufacturing capacity carries the system components on the confines of two transportable vehicles. The two vehicles are arranged in a fashion whereby vehicle one is connected to vehicle two in an inline continuous fashion. Vehicle two contains an integrated inertial dust separator baghouse design and provides for the receiving of the rotary dryer drum mixer directly and without the use, of interconnecting ductwork. | 5 |
This is a division of application Ser. No. 926,454 filed Nov. 3, 1986, now U.S. Pat. No. 4,719,891.
FIELD AND BACKGROUND OF THE INVENTION
The invention concerns a system having an electronic controller for internal combustion engines, particularly injection engines, in which the controller is functionally connected to a plurality of sensors and at least one actuator.
Electronic control systems for internal combustion engines consist of a plurality of components such as, for instance, sensors, the controller and actuators, which in known systems are distributed on the internal combustion engine and/or in the engine compartment of an automotive vehicle. In this way, corresponding plug-in connections and lines are necessary, which can give rise to disturbances. Furthermore, the plug-in connections and the lines represent a further expense. In addition, there are a corresponding number of protective housings or caps which protect the components, or at least the connections of the components, from external influences (moisture, dirt).
SUMMARY OF THE INVENTION
It is an object of the present invention therefore to provide a system having an electronic controller for internal combustion engines in which lines and plug-in connections are reduced to a minimum.
According to the invention, the controller (15) is part of an assembly which furthermore comprises a throttle-valve arrangement (3,4), an air-mass sensor (12) and a throttle-valve position sensor (16).
Aside from the advantage that long connecting lines which are subject to faults are eliminated, there is the advantage that the closed assembly can be removed from the internal combustion engine for maintenance and repair and be calibrated, for instance, on a test bench.
According to a further development of the invention, a housing (1) can be connected to the intake port of the internal combustion engine, the throttle-valve arrangement (3,4) is provided in a length of pipe (4) which forms the connection between housing (1) and intake port, and the air-mass sensor (12) is arranged in the housing (1) while the controller (15) is arranged on a wall (7) of the housing (1). This development permits an extremely favorable connection of the assembly to the internal combustion engine.
Another further development is that within the housing (1) there is arranged an injection valve (5) which is associated as actuator with the controller (15). This development can be advantageously employed in injection engines with so-called central injection in which merely one injection valve is provided for all the cylinders. However the invention can also be advantageously used in internal combustion engines in which an injection valve is provided for each cylinder.
A further improvement of the invention is that an air filter arrangement (8) which has a circular air filter (9) is arranged on an outer wall (7) of the housing (1) and that the inner space formed by the circular air filter (9) is connected to the inside of the housing (1) by a flow channel (13) within which the air-mass sensor (12) is arranged.
Another favorable embodiment is possible here in which the electronic controller (15) is arranged on the outer wall (7) of the housing (1) and extends into the inside (10) of the air-filter arrangement (8).
In this way, good cooling of the electronic controller is provided by the filtered air which is drawn in.
In accordance with another feature, a pressure sensor (24) and/or temperature sensor (25) can furthermore be arranged in the interior (10) of the air-filter arrangement (8).
Furthermore, it is possible to provide an engine-temperature sensor (26) and/or an intake manifold temperature sensor (26) within the region of the throttle-valve arrangement (3,4).
According to another embodiment, the shaft (4) which bears the throttle valve (3) is operatively connected to a switch (17) which responds at the idle position of the throttle valve (3).
Further circuits (32, 33, 34) corresponding to respective sensors (12, 16, 26) are combined spatially with the electronic controller (15) but functionally represent assemblies which are separate from the electronic controller.
Still further, electric circuits corresponding to respective sensors (12, 16, 26) are combined both spatially and functionally with the electronic controller (15).
Also, the injection valve (5) can be combined with a system-pressure controller (18).
The arrangement in accordance with the invention can be used in different control systems for internal combustion engines. A preferred use is the known control of the amount of fuel injected in Otto engines with fuel injection. For the regulating of the amount injected, the known control systems primarily utilize the mass of air drawn in by the engine. However, for the control, there are also taken into account the position of the throttle valve, the external air pressure (i.e. the altitude), the engine temperature, the temperature of the outside air, the speed of rotation of the engine and the result of the measurement provided by a lambda probe. A plurality of sensors which detect these variables can be arranged within the assembly in the arrangements according to the invention. However, additional sensors (for instance speed of rotation of the engine, lambda probe) can also be connected to the assembly by suitable lines.
The known control systems also permit the electronic controller (15) to contain an idling control on the output of which an idling setter (28) is provided in the region of the throttle-valve arrangement (3, 4).
Further, the arrangement of the invention is not limited to mechanical actuation of the throttle valve. One embodiment of the invention rather resides in the fact that the electronic controller (15) comprises a controller of an electronic gas-pedal system and that the throttle-valve arrangement (3,4) is provided with an electromotive actuator (27) which is connected to an output of the electronic controller (15) intended for this purpose.
The lines between the sensors present (12, 16, 17, 24-26) as well as actuators (5, 27, 28) and the electronic controller (15) can advantageously extend, at least in part, within the housing (1).
Further sensors and/or actuators arranged spatially outside of the assembly can be connected to the electronic controller.
BRIEF DESCRIPTION OF THE DRAWINGS
With the above and other objects and advantages in view, the present invention will become more clearly understood in connection with the detailed description of preferred embodiments, when considered with the accompanying drawings, of which:
FIG. 1 is a longitudinal sectional view of a first embodiment in which the only sensors are an air-mass sensor and a throttle-valve position sensor;
FIG. 1a is a cross-section through the housing of FIG. 1;
FIG. 2 is a view similar to FIG. 1 of a embodiment having a plurality of sensors; and
FIG. 3 is a diagrammatic showing of the controller and of the sensor circuits.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Identical parts have been provided with the same reference numbers in the figures.
In the arrangement shown in FIG. 1, a housing 1 having the shape of a squat cylinder is placed on a pipe 2 which contains a throttle valve 3 which is fastened on a shaft 4. A fuel injection valve 5 having a nozzle 6 is arranged above the mouth of the pipe 2. The housing 1 is closed off on the top by a wall 7 on which an air filter 8 is placed. The air filter 8, which is known per se, consists of an annular filter 9 which forms a hollow space 10. The inside space 10 of the air filter as well as the inside 11 of the housing 1 are connected by a flow channel 13. The flow channel contains an air-mass sensor 12 and is relatively long in order to obtain the best possible laminar flow. In order to achieve this in a small space, the flow channel 13 extends in annular shape along the outer wall of the housing 1. The filtered air enters the flow channel 13 at the inlet opening 14, which, at the same time, represents an opening in the wall 7, and then flows past the sensor 12 and is conducted, via the outlet opening 14a, into the rest of the hollow space 11 of the housing 1. The hollow space 11 furthermore serves to dampen the pulsation in the intake port.
An electronic controller 15 is located on the partition wall 7, the controller being of known operation and therefore not having to be described here in detail. The measurement signals of the air-mass sensor 12 and of a throttle-valve position sensor 16 are fed as input variables to the electronic controller 15. The throttle-valve position sensor 16 consists, in known manner, of a potentiometer whose wiper is coupled to the throttle-valve shaft 4. Furthermore a switch 17 for the switching of the control for idling operation is connected, also in known manner, to the throttle-valve shaft 4 and to the electronic controller 15.
The output signals of the controller 15 are fed to the fuel injection valve 5 via short lines. In the embodiment shown in the drawing, the fuel injection valve 5 is combined with a system-pressure controller 18. The fuel feed line 20 and the fuel return line 21 serve for connection with a fuel tank 19. Finally, operating voltage is fed to the controller 15 via an electric line 22, which is also merely diagrammatically shown. In order to avoid any effect of variations in the voltage of the automobile electrical system on the controller, the controller 15 is provided with a voltage stabilization circuit (not shown in FIG. 1).
In order to make the course of the flow channel clear, FIG. 1a shows a cross section through the housing 1 in which there is also shown a flow straightener 41 and a protective grating 42 which have been omitted from FIG. 1 for the sake of clarity.
The embodiment according to FIG. 2 presupposes a control system having a plurality of possibilities. For this purpose, controller 15 is provided not only with the input variables explained in connection with FIG. 1 but also with information concerning the pressure of the outer air, i.e. the altitude, via a pressure sensor 24 which is located in the space 10 of the air filter 8.
A temperature sensor 25 which determines the temperature of the outside air is also present in the space 10 of the air filter 8.
For various known control systems the motor temperature is required as one of the input variables. For this purpose, in the system according to the invention, in place thereof the intake-manifold temperature in the vicinity of the throttle-valve arrangement can be detected by another sensor 26.
Finally the control system can also comprise a so-called electronic gas-pedal system in which the position of the gas pedal is converted into an electric variable which acts on the throttle valve via a controller. The controller 15 can be suitably designed for this purpose and have an additional output to which an electromotive throttle-valve actuator 27 is connected.
FIG. 3 shows the electrical circuit of the arrangements of FIGS. 1 and 2 diagrammatically, in part as block diagram. Some of the sensors concerned require, for their operation, electric circuits which are specifically adapted to the nature of the sensors. Sensors are also known which give off very small electrical signals which must be amplified before they are further used. For this purpose, electric circuits are frequently arranged directly on the sensors. Due to the compact construction of the arrangement in accordance with the invention, it is possible to combine such circuits with the controller 15 within a housing 31.
Depending on the specific use, it may be advantageous to develop the circuits corresponding to the individual sensors--referred to below as sensor circuits--in each case as separate modules 32, 33, 34 which are connected to the controller 15 and the respective sensors 12, 26, 16 merely by a few lines. This arrangement has the advantage that when the system of the invention is adapted to, for instance, different internal combustion engines for which different sensors are required, merely one or more of the units 32, 33, 34 need be replaced. The connecting of the corresponding sensors circuit 32, 33, 34 to the controller 15, which, at the same time, also takes over the supplying of the sensor circuits with the operating voltage, is effected, in principle, by three lines. Two of them are used for the operating voltage and the ground connection respectively while the third is used for conducting the output signal of the corresponding sensor circuit to the controller 15. This line can conduct an analog signal of the measurement variable or, in the event of digital signal processing within the controller, also a digital signal. In such case, an analog-digital converter would have to be provided in the sensor circuit.
Three sensors are present in the arrangement shown in FIG. 3. The air-mass sensor 12 consists of a first temperature-dependent conductor 35 and a second temperature-dependent comparison conductor 36. The two conductors are bathed by the stream of air. The conductor 35 is heated to a constant temperature which is substantially above the temperature of the air by a current which is fed from the sensor circuit 32. The sensor circuit 32 contains a controller circuit in which the temperature is detected by the temperature dependence of the resistance of the resistor 35 and the current fed to the resistor 35 is controlled so as to maintain the temperature constant. The value of the current is then a measure of the air mass. In order to compensate for the influence of the temperature of the air, a comparison conductor is arranged in the vicinity of the conductor 35, said comparison conductor however being passed through by a small current so that, for all practical purposes, it is not heated above the air temperature. A temperature-dependent resistor 37 which serves, for instance, as motor or intake-pipe temperature sensor 26 is connected to the sensor circuit 33. It is part of a bridge circuit which is furthermore arranged in the sensor electronics 33.
Finally, the sensor circuit 34 is connected to a potentiometer 38 which serves as throttle-valve position indicator. Within the housing there is also arranged a known voltage-stabilization circuit 39 which is connected to the automobile electrical system via the input 22 and provides a stabilized operating voltage for the controller 15 as well as for the sensor circuits 32, 33, 34. The output 40 of the controller 15 is connected to the injection valve 5 (FIG. 1, FIG. 2).
In other cases it may be more favorable to integrate the sensor circuits 32, 33, 34 in the controller 15 rather than to develop them as separate units. This has the advantage that the solder or plug connections between the units 32, 33, 34 and the controller 15 can also be dispensed with. In such cases changes in the controller 15 itself would be necessary in order to adapt the controller 15 to the different sensors. | In a system having an electronic controller for internal combustion engines, particularly injection engines in which the controller is functionally connected to a plurality of sensors and at least one actuator, the controller is part of an assembly which furthermore comprises a throttle-valve arrangement, an air-mass sensor and a throttle-valve position sensor. In systems with central injection, the injection valve can also be arranged within the assembly. By the compact structural unit thus obtained, cable connections are reduced to a minimum, so that, in their turn, reliability is increased and expense is saved. Furthermore, the arrangement facilitates maintenance and repair. | 8 |
BACKGROUND
The invention is directed to a top transport device for sewing machines, in particular, with a presser bar and presser foot arrangement.
Top transport devices on sewing machines are known. They are used to also transport the sewing material from the top side in the sewing direction in sync with the feed dog arranged under the sewing material in the lower arm and therefore to guarantee that there is no mutual shift between the material on the top and the material on the bottom.
A known device is described in DE-C1 3435633. This device comprises, in addition to the spring-loaded presser bar, which is mounted for vertical movement on the sewing machine and to which the presser foot is fixed on the bottom, a top transport foot, which is driven by an arm in active connection with the drive of the sewing machine. If the top transport foot is to be activated, then it is connected by the sewer to the bottom end of the arm, i.e., suspended on the bottom end and held there by a spring pulling back the top transport foot. Here, the bottom arm end engages the shaft of the top transport foot. In contrast, if the top transport foot is not needed, then it can be disconnected from the arm and then slides upwards, pulled by the spring, until the foot end contacts the bottom end of the arm. The bottom of the top transport foot then always lies at a distance of about 15 mm from the needle plate and no longer influences the sewing process. However, the distance of the top transport foot bottom is small, such that no known accessories can be fixed to the presser bar. In addition, handling by the sewer in the area of the presser foot is obstructed by the top transport foot.
SUMMARY
One objective of the present invention is to create a top transport device, which can be moved upwards when not needed such that conventional accessories can be fixed to the presser bar and optimal handling of the sewing material is possible when the top transport is not needed.
Another objective of the present invention is to form the top transport such that it can be adjusted relative to the presser foot and the needle plate without disassembling the housing part.
These are met by a top transport device according to the invention. Advantageous configurations of the device are described in the dependent claims.
By dividing the arm, at least partially, into two parallel, spaced arm sections that guide the shaft of the top transport foot laterally, the top transport foot can be drawn upwards to a much greater extent and thus the area above the needle plate can be kept open for the installation of special devices.
Another advantage of the invention in one preferred embodiment is that no parts on the machine housing have to be removed for setting the top transport foot in the sewing direction and in the vertical direction. There is the further possibility of exchanging a top transport foot similar to the presser foot and replacing it with a foot that is adapted to the sewing material to be processed. In another advantageous configuration, only the foot bottom on the top transport foot can be exchanged in order to adapt its structure to the sewing material to be processed.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is explained in more detail with reference to an illustrated preferred embodiment. In the drawings:
FIG. 1 is a front view of a sewing machine from the operator side;
FIG. 2 is a view of the sewing machine from the direction of the arrow P in FIG. 1 with a schematic top transport device;
FIG. 3 is an enlarged representation of the presser bar, the presser foot, and also the top transport device, top transport foot in raised position;
FIG. 4 is an enlarged representation of the presser bar, the presser foot, and also the top transport device, top transport foot in lowered position, directly at the beginning of the transport of the sewing material;
FIG. 5 is an enlarged representation of the presser bar, the presser foot, and also the top transport device (partially cut away), with the top transport foot in a lowered position, directly at the end of the transport of the sewing material;
FIG. 6 is a view of the top transport device and the presser foot from the direction of the arrow H in FIG. 2 (top transport in working position);
FIG. 7 is a view of the top transport device and the presser foot from the direction of the arrow H in FIG. 2 (top transport in rest position);
FIG. 8 is a perspective view of the top transport device with exchangeable top transport foot and adjustment device;
FIG. 9 is a perspective representation of the arm, which carries the top transport foot;
FIG. 10 is a cross section through the height adjustment device for the top transport foot;
FIG. 11 is a longitudinal section through a first embodiment of an exchangeable top transport foot;
FIG. 12 is a longitudinal section through a second embodiment of an exchangeable top transport foot;
FIG. 13 is a perspective representation of a replacement bottom for a top transport foot; and
FIG. 14 is a perspective representation of the replacement bottom fixed on the top transport foot.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
In FIG. 1 , a household sewing machine with the reference symbol 1 can be seen shown schematically with a free arm 3 , an upper arm 5 , and a base plate 7 , on which the housing part 9 carrying the upper arm 5 and the free arm 3 is arranged. Furthermore, a presser bar 11 and a presser foot 13 attached to this presser bar can be seen. In the front view according to FIG. 2 , behind the presser bar 11 , a top transport foot 15 and a driving arm, designated as arm 17 below, activating the top transport foot 15 , can be seen. In addition, a needle 19 and the needle rod 21 are shown above the presser foot 13 .
In FIGS. 3 to 7 , which present the parts essential to the invention at an enlarged scale, in addition to the top transport foot 15 and the arm 17 , the driving means for the arm 17 are also shown but not described in more detail. The driving means move the arm 17 , when this is lowered, in sync with the feed dog (not shown). The kinematics of the driving gear, which include a plurality of levers and cams are not described here in more detail, because they can correspond, for example, to those from the state of the art. Obviously, other driving systems for the movement of the arm 17 are also possible.
The two primary elements of the top transport according to the invention are the configuration of the top transport foot 15 and the arm 17 . The arm 17 comprises two spaced, parallel arm sections 17 a and 17 b , which are held connected to each other and form in-between a guidance space. The top and bottom end of the arm 17 can be held together by connecting members 23 and 24 ( FIG. 9 ). In addition, the top ends of the two arm sections 17 a , 17 b are coupled to the driving kinematics by a bolt 25 , which penetrates the bore holes 26 in the arm sections 17 a , 17 b (see FIG. 3 ). In addition, a longitudinal guidance slot 27 is formed in each of the two arm sections 17 a , 17 b . These two guidance slots 27 are used for guiding the top transport foot 15 , at whose top end a guidance bolt 28 engaging in the guidance slot 27 is inserted ( FIG. 4 ).
The top transport foot 15 is guided laterally with slight play in the guidance space between the inner sides of the two arm sections 17 a , 17 b . In the raised position ( FIG. 3 ), the top transport foot 15 lies with its top end and also with its bottom end close to the top transport foot bottom 29 between the two arm sections 17 a , 17 b.
The top transport foot 15 has the shape of a two-armed lever, with the connecting point 14 (knee) of the two lever sections 16 a , 16 b coming to lie outside of the two arm sections 17 a , 17 b in the raised position. The top transport foot 15 is then guided laterally in the region of its upper lever section 16 b with the guidance bolt 28 in the guidance slots 27 on the arm 17 , and in the region of its lower lever section 16 a in the guidance space of the arm 17 . The connecting point 14 , i.e., the knee, projects backwards from the guidance space. The two ends of the bolt 28 at the end of the upper lever section 16 b of the top transport foot 15 contact the upper end of the slot 27 in the rest position. In this rest position, the top transport foot 15 is held by a spring 31 , which is suspended on one side on the connecting member 23 between the brackets 33 on the arm 17 and is held on the other side on the top transport foot 15 (holding point cannot be seen). In order to impart a defined position to the top transport foot 15 , at least one guidance cam 35 is formed on this top transport foot. This cam—when the top transport foot 15 is not in the working position—slides on the rear edges of the two arm sections 17 a , 17 b . Consequently, the tip of the top transport foot bottom 29 is located in the rest position at the height of the bottom end 20 of the arm 17 and approximately at the height of a connecting point between the presser foot 13 and the presser bar 11 (see FIG. 3 ).
In the working position ( FIG. 4 ), the top transport foot 15 is pulled or pushed downwards against the force of the spring 31 on the cam 37 by hand, guided upwards with the bolt 28 in the guidance slots 27 , and guided laterally between the arm sections 17 a , 17 b . In this way, the top transport foot 15 pivots in the direction against the presser foot 13 and engages in the recess 18 formed there ( FIG. 8 ). When the top transport foot 15 is guided downwards, at least the guidance cam 35 slides on the upper leg of the top transport foot 15 under the bottom end 20 of the arm 17 (shown in FIGS. 5 & 8 ) and locks there. In this position, the top transport foot 15 is in active connection with a positive fit with the arm 17 and can be driven by this arm and the rods engaging the arm at the top. The tensile force of the spring 31 maintains the connection. The position of the top transport foot 15 shown in FIG. 4 relative to the presser foot 13 is also maintained when the presser foot is lowered onto the sewing material, because the arm 17 and its drive follow the vertical movement in sync when the presser bar 11 is lowered.
From the perspective representation in FIG. 8 and in FIG. 10 , which present a preferred refinement of the invention, adjustment devices for adjusting the top transport foot 15 relative to the presser foot 13 are shown. The top transport foot 15 is adjusted in the vertical direction by a cam plate 44 , which is mounted on a threading-free section of a threaded bolt 39 so that it can rotate, and can be secured by a nut 41 (see FIG. 10 ). The other end of the threaded bolt 39 is connected rigidly to an extension arm 43 projecting from the arm 17 . By rotating the cam plate 44 on the threaded bolt 39 , the vertical position of the arm 17 is defined and thus also the vertical position of the top transport foot 15 fixed to the arm.
The top transport foot is adjusted in the horizontal direction by two locking screws 45 , which engage in a slot 48 formed in an attachment lever 47 coupled to the sewing machine housing. For better clarity, in FIG. 8 the locking screw 45 of the front attachment lever 47 is not shown or has been left out in order to make the slot 48 visible. The attachment lever 47 is connected to a rocker arm 51 in an articulated way with a connecting member 49 . By loosening the locking screws 45 and moving the attachment brackets 47 in the slot, the arm 17 is pushed horizontally by the connecting member 49 , which is coupled to the attachment lever 47 .
The top section 16 b of the top transport foot 15 is guided by the guidance bolt 28 in the slots 27 of the arm 17 . This connection can be released by suitable means in the first embodiment according to FIG. 11 and thus the top transport foot 15 can be removed from the arm 17 and replaced by a foot with a differently shaped bottom 53 . Before the top transport foot 15 is removed, the connection between the spring 31 and the top transport foot 15 must be loosened. The top transport foot 15 is loosened from the arm 17 , in that the hook-shaped top end 30 , which is locked on the guidance bolt 28 , is loosened from this bolt (hook-shaped end 30 visible in FIG. 11 ).
In the second embodiment according to FIG. 12 , the lower leg 16 a of the top transport foot 15 is formed so that it can be released from the upper leg 16 b . The top end of the lower leg 16 a engages in a slot 32 in the connecting point 14 to the upper leg 16 b and can be fixed with a suitable latching element 34 . A tension screw or the like can be used as the latching element 34 .
In the third embodiment according to FIGS. 13 and 14 , only the bottom 53 on the lower leg 16 a is removed for changing the properties of the top transport foot 15 . The connection between the bottom 53 and the lower end 55 of the lower leg 16 a can be realized, for example, by a close sliding fit, a dovetail joint, or the like.
The replacement of the top transport foot 15 by another foot with a differently shaped bottom 53 is used to adapt the top transport foot 15 to the sewing material to be processed or to the surface properties of this material. Very fine materials, such as silk, require differently shaped top transport foot bottoms 53 than materials with a very rough structure.
Legend
1
Household sewing machine
3
Free arm
5
Upper arm
7
Base plate
9
Housing part
11
Presser bar
13
Presser foot
14
Connecting point of 15a/16b
15
Top transport foot
16
Shank of 15
17
Arm
18
Recess in 13
19
Needle
20
Lower end of 17
21
Needle bar
23
Connecting element (top)
24
Connecting element (bottom)
25
Bolt
(transfers advance to 17)
26
Bore holes for 25
27
Slot
28
Guidance bolts, engaging in slots
29
Transport base
30
Top hook-shaped end
31
Spring
32
Slot
33
Bracket
34
Latching means
35
Guidance cams
37
Cams
39
Threaded bolt
41
Nut
43
Extension arm
44
Cam plate
45
Clamping screw
47
Attachment lever
48
Slot
49
Connecting element
51
Rocker arm
53
Base of 15
55
Lower end of 16a | In the top transport device of a sewing machine, the top transport foot ( 15 ) moves in a vertical slot ( 27 ) in the arm ( 17 ), with which the top transport foot ( 15 ) is driven. This arrangement enables the top transport foot ( 15 ) to be displaced upwards into the rest position, so that accessories can be fixed to the presser bar ( 11 ). | 3 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to Venetian blinds and, more specifically, to such a Venetian blind that keeps the lift cords concealed.
2. Description of the Related Art
A regular Venetian blind is generally comprised of a top rail, a bottom rail, a plurality of slats arranged in parallel between the top rail and the bottom rail, a lift control mechanism for controlling lifting and positioning of the bottom rail to adjust the extending area of the Venetian blind, and a tilting control mechanism for controlling the tilting angle of the slats to regulate the light. The lift control mechanism comprises a lift cord suspended from the top rail at one side for operation by hand to control the elevation of the bottom rail. Because the lift cord is exposed to the outside, it destroys the sense of beauty of the Venetian blind. Further, because a child can easily reach the exposed lift cord, an accident may occur when the child pulls on the lift cord for fun. In order to eliminate this problem, Venetian blinds with receivable lift cord(s) are developed. Exemplars of these Venetian blinds are seen in U.S. Pat. Nos. 2,382,100; 5,531,257; and 3,014,124. However, these Venetian blinds commonly have a complicated structure and high manufacturing cost.
SUMMARY OF THE INVENTION
It is the main object of the present invention to provide a Venetian blind, which keeps the lift cords concealed and out of reach of children.
It is another object of the present invention to provide a Venetian blind, which enables the user to control the lifting and positioning of the slats easily.
It is still another object of the present invention to provide a lift cord concealable Venetian blind, which has a simple structure and, is inexpensive to manufacture.
To achieve these objects of the present invention, the Venetian blind comprises a headrail, a bottom rail, a set of slats, at least one lift cord, each lift cord having a first end fixedly fastened to the bottom rail and a second end upwardly inserted through the slats into the inside of the headrail and extended transversely to one end of the headrail and then turned downwards to the outside of the headrail, and a sleeve suspended from the headrail and adapted for receiving the second end of each lift cord for enabling the second end of each lift cord to be selectively positioned in one of a series of vertical positions in the sleeve.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic drawing of a first embodiment of the present invention, showing the Venetian blind extended out.
FIG. 2 is a schematic drawing corresponding to FIG. 1, showing a received status of the Venetian blind.
FIG. 3 is a schematic drawing showing the lift cord endpiece disengaged from the elongated retaining notches for free movement along the longitudinal slot according to the first embodiment of the present invention.
FIG. 4 is a top view of FIG. 3 .
FIG. 5 is similar to FIG. 3 but showing the lift cord endpiece engaged in one elongated retaining notch of the sleeve.
FIG. 6 is a top view of FIG. 5 .
FIG. 7 is a schematic structural view showing the connection between the lift cords and the lift cord endpiece according to the first embodiment of the present invention.
FIG. 8 is a schematic structural view of a Venetian blind according to a second embodiment of the present invention.
FIG. 9 is a perspective exploded view of a part of the second embodiment of the present invention, showing the structure of the winding mechanism.
FIG. 10 is a schematic side view showing the bobbin of the winding mechanism locked according to the second embodiment of the present invention.
FIG. 11 is similar to FIG. 10 but showing the bobbin unlocked.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIGS. from 1 through 7 , a Venetian blind 10 is shown comprising a headrail 12 fixedly transversely fastened to the top side of the window, the headrail 12 having a first end 13 (the right end), a bottom rail 14 extended in transverse direction and spaced below the headrail 12 , a number of slats 16 arranged in parallel between the headrail 12 and the bottom rail 14 , a sleeve 20 , two lift cords 30 , and a lift cord endpiece 40 .
The sleeve 20 is a straight tube vertically suspended from the first end 13 of the headrail 12 (alternatively, the sleeve can be fixedly fastened to one lateral side of the window), keeping the inside space in communication with the inside space of the headrail 12 . The sleeve 20 has a longitudinal slot 22 longitudinally extended between the top and bottom ends, and a plurality of elongated retaining notches 24 obliquely upwardly extended from the longitudinal slot 22 at different elevations at an equal pitch. According to this embodiment, the elongated retaining notches 24 are respectively extended from the longitudinal slot 22 at the same time. Alternatively, the elongated retaining notches 24 can be alternatively extended from the longitudinal slot 22 at two sides at different elevations.
The lift cords 30 have a respective first end symmetrically fixedly fastened to the bottom rail 14 , and a respective top end upwardly inserted through a respective through hole (not shown) in each slat 16 and then inserted into the inside of the headrail 12 and then extended in the same direction toward the first end 13 of the headrail 12 and then extended downwards to the inside of the sleeve 20 (alternatively, one single lift cord may be used and inserted through a first through hole in each slat 16 and the bottom rail 14 and then inserted through a second through hole in the bottom rail 14 and each slat 16 and then extended through the headrail out of the first end 13 of the headrail 12 to the inside of the sleeve 20 ; subject to the size of the Venetian blind, three lift cords may be used).
The lift cord endpiece 40 comprises a barrel-like body 41 received in the sleeve 20 , the body 41 having a bottom chamber 42 and a center through hole 43 axially disposed in communication with the bottom chamber 42 , a rod 44 perpendicularly extended from the periphery of the body 41 and extended through the longitudinal slot 22 of the sleeve 20 , and a spherical knob 45 fixedly fastened to the end of the rod 44 and disposed outside the sleeve 20 . The diameter of the rod 44 is smaller than the width of the longitudinal slot 22 and the elongated retaining notches 24 . The diameter of the spherical knob 45 is greater than the width of the longitudinal slot 22 and the elongated retaining notches 24 . The body 41 of the lift cord endpiece 40 is fastened to the second ends of the lift cords 30 inside the sleeve 20 . As illustrated in FIG. 7, the second end of each lift cords 30 is inserted through the center through hole 43 into the inside of the body 41 and then tied up into a knot inside the bottom chamber 42 of the body 41 .
The Venetian blind 10 further comprises a tilting control mechanism adapted for controlling the tilting angle of the slats. Because the tilting control mechanism is of the known art and not within the scope of the claims of the present invention, no further detailed description in this regard is necessary.
According to the aforesaid structure, the user can hold the spherical knob 45 of the lift cord endpiece 40 to move the lift cord endpiece 40 along the longitudinal slot 22 to the desired elevation (see FIGS. 3 and 4 ). When pulled the lift cord endpiece 40 downwards to lower the second ends of the lift cords 30 , the bottom rail 14 is lifted with the first ends of the lift cords 30 , thereby causing the slats 16 to be received to the headrail 12 . On the contrary, when reducing the pull force from the lift cord endpiece 40 , the bottom rail 14 will fall to the bottom side due to the effect of its gravity weight, thereby causing the slats 16 to be lowered and extended out and the lift cords to be pulled downwards with the bottom rail 14 to lift the lift cord endpiece 40 . When the user moved the lift cord endpiece 40 sideways to force the rod 44 into one elongated retaining notch 24 , as shown in FIGS. 5 and 6, the lift cord endpiece 40 is locked, and therefore the bottom rail 14 is stopped in position, keeping the blind in the corresponding extended status.
As indicated above, the user can easily control the lifting and positioning of the Venetian blind 10 . Further, because the protruded sections of the lift cords 30 outside the headrail 12 are received in the sleeve 20 , the lift cords 30 are kept out of reach of children and prohibited from hooking the arm or neck of the person touching or operating the Venetian blind 10 accidentally.
FIGS. from 8 through 11 show a Venetian blind according to a second embodiment of the present invention. According to this alternate form, the Venetian blind 50 comprises, a headrail 52 , a bottom rail 54 , a set of slats 56 , a sleeve 60 , a winding mechanism 70 , and two lift cords 80 . The structure and arrangement of the headrail 52 , bottom rail 54 and slats 56 of this embodiment are same as the corresponding members of the aforesaid first embodiment of the present invention. According to this embodiment, the sleeve 60 is a straight tube of rectangular cross section suspended from the headrail 52 . The top end of the sleeve 60 is fastened to the bottom side of the first end 53 of the headrail 52 . The sleeve 60 has a proper length such that the user's hand is conveniently reachable to the bottom end of the sleeve 60 for operation. The sleeve 60 has two pivot holes 63 ; 64 respectively disposed in front and rear sidewalls 61 ; 62 thereof, and a plurality of, for example, four locating holes 65 disposed in the rear sidewall 62 around the corresponding pivot hole 64 .
The winding mechanism 70 is mounted in the bottom end of the sleeve 60 , comprised of a bobbin 71 , a handle 76 , and a spring 77 . The bobbin 71 comprises a body 72 , a front round rod 73 axially extended from the center of one end of the body 72 , a rear round rod 74 axially extended from the center of the other end of the body 72 , and a pin 75 protruded from one end of the body 72 adjacent to the rear round rod 74 . The round rods 73 ; 74 are respectively pivotally mounted in the pivot holes 63 ; 64 of the sleeve 60 . After installation of the bobbin 71 in the sleeve 60 , the bobbin 71 can be rotated on its own axis, and moved axially between the sidewalls 61 ; 62 of the sleeve 60 within a limited arrange (between the position shown in FIG. 10 and the position shown in FIG. 11 ). The handle 76 may be various shaped. According to this embodiment, the handle 76 is a crank handle fastened to the end of the front round rod 73 and disposed outside the sleeve 60 for operation by hand to rotate the bobbin 71 causing it to wind up the lift cords 80 . The spring 77 is mounted on the front round rod 73 inside the sleeve 60 , having one end stopped at the inner surface of the front sidewall 61 of the sleeve 60 and the other end stopped against one end of the body 72 of the bobbin 71 . According to this embodiment, the spring 77 is a compression spring that forces the bobbin 71 backwardly away from the front sidewall 61 of the sleeve 60 toward the rear sidewall 62 , keeping the bobbin 71 in the rear position shown in FIG. 10 .
The lift cords 80 each have a first end fixedly fastened to the bottom rail 54 , and a second end upwardly inserted through the slats 56 into the inside of the headrail 52 and then extended transversely to the first end 53 of the headrail 52 and then turned vertically downwards into the inside of the sleeve 60 and fixedly fastened to the periphery of the body 72 of the bobbin 71 (in the drawings, the second ends of the lift cords 80 are joined into one single rope in the sleeve 60 and then fixedly fastened to the periphery of the body 72 of the bobbin 71 ).
Normally, the spring 77 holds the bobbin 71 in the rear position where the pin 75 is engaged into one locating hole 65 of the sleeve 60 to stop the bobbin 71 from rotation, keeping the second ends of the lift cords 80 fixed to the bottom end of the sleeve 60 , and therefore the bottom rail 54 is held in position. When adjusting the extending area of the blind, the user can pull the handle 76 outwards to disengage the pin 75 from the locating holes 65 of the sleeve 60 (see FIG. 11 ), and then rotate the handle 71 clockwise or counter-clockwise, causing the bobbin 72 to wind up or let off the lift cords 80 . When the bobbin 72 rotated clockwise to wind up the lift cords 80 , the bottom rail 54 is lifted. On the contrary, when the bobbin 72 rotated counter-clockwise to let off the lift cords 80 , the bottom rail 54 is lowered. When the bottom rail 54 adjusted to the desired elevation, release the hand from the handle 76 , enabling the pin 75 of the bobbin 71 to be forced into one locating hole 65 of the sleeve 60 by the spring power of the spring 77 to lock the bobbin 71 again (see FIG. 10 ).
The aforesaid winding mechanism may be variously embodied. Further, a spiral or torsional spring may be used to impart a winding force to the bobbin. | A Venetian blind is constructed to include a headrail, a bottom rail, a set of slats, at least one lift cord, each lift cord having a first end fixedly fastened to the bottom rail and a second end upwardly inserted through the slats into the inside of the headrail and extended transversely to one end of the headrail and then turned downwards to the outside of the headrail, and a sleeve suspended from the headrail and adapted for receiving the second end of each lift cord for enabling the second end of each lift cord to be selectively positioned in one of a series of vertical positions in the sleeve. | 4 |
FIELD OF THE INVENTION
A drain grate in an opening into a drain system which when closed retains trash and debris upstream from the opening while permitting slow flow of water, and which opens completely when confronted with high rates of water flow.
BACKGROUND OF THE INVENTION
Drainage systems that are situated in locations where trash and debris are carried along with the water are ubiquitous. In particular, unless prevented storm drains such as are found in gutters and drainage channels receive trash, cuttings, trimmings and other debris constantly throughout the year and are subject to clogging. During clement weather, the flow of water is usually rather slow, and is insufficient to flush the system, especially at catch basins and bends. Instead, despite regular sweeping upstream from the opening, considerable amounts of trash will enter the drain system, while still permitting the slow flow of water.
Serious trouble arises when later storms or other circumstances present water to these systems at high rates of flow while they are congested with the accumulated trash. Clogging of this system can result in upstream flooding, or the washing downstream of the accumulated material to do its mischief downstream. To avoid this situation, throughout the year maintenance crews are sent to clear out trash and debris that has entered the system through the openings. This is a considerable expense, and in the event that a storm strikes before the system is cleared, serious damage can occur despite those earlier efforts.
It is an object of this invention to provide a gate which will exclude trash and debris from the system while still permitting a slow flow of water, but which will open to allow full access for water (and entrained material) when the rate of flow is sufficiently high. When closed, the gate will permit the trash upstream from it to be removed by routine and collection sweeping, so as to remove trash that otherwise would later be driven into the system.
DETAILED DESCRIPTION OF THE INVENTION
This invention comprises a pivoted grate which is placed where it can occlude an opening from a drain into a collection system, or pivot to expose the opening to full flow. The grate is ported or otherwise channeled to allow water to pass through it when closed while retaining trash at low flow rates. In this condition, low flow rates such as are developed by watering of lawns, minor rains and the like are permitted, while holding back trash from the system where the trash can readily be swept away or otherwise removed without entering the drain system itself.
Under these benign conditions a linkage system which includes a variable-weight actuator allows the grate to close. When the weight increases as the consequence of a sufficiently higher rate of flow, the increased weight of the actuator will open the grate.
According to a feature of this invention, the actuator comprises a receptacle with a bleed port, which prevents the actuator from accumulating sufficient water (weight) to open the grate at slow rates of water flow, but which will accumulate sufficient water at higher rates to open the grate.
According to a preferred but optional feature of the invention, the actuator is mounted to a linkage which includes a toggle that prevents the grate from being opened by a force applied directly to the grate.
The above and other features of this invention will be fully understood from the following detailed description and the accompanying drawings, in which:
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view showing a grate according to the invention installed in a curb opening, with the grate closed;
FIG. 2 is a view like FIG. 1, with the grate fully open to flow;
FIG. 3 is a side view partly in cross-section, showing a simple form of the invention installed as in FIG. 1 with the grate closed;
FIG. 4 is a view like FIG. 3, except that the grate is pivoted to open the curb opening;
FIG. 5 is a side view, partly in cross-section showing the presently-preferred embodiment of a grate system in its closed position;
FIG. 6 is a view like FIG. 5 showing the system with its grate open;
FIG. 7 is a side view partly in cross-section showing yet another system according to the invention; and
FIG. 8 is a perspective view of a preferred actuator for use in any of the embodiments.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a street-side installation of the invention. A typical gutter 10 and curb 11 are shown with an opening 12 to receive a grate 13 . An access cover 14 is placed over an access hole 15 in the top surface 16 . A collection basin 17 below hole 15 is provided to collect trash and debris which may somehow get through the opening. A pipe 18 leads to a drainage system (not shown).
Grate 13 is illustrated in FIG. 1 as a coarse screen. More frequently it may be a comb-like group of parallel rods, depending on the kind of location, and what is expected to be screened out. In any event clearances (sometimes called “gaps”) are provided to enable water to flow through the grate, while retaining trash, debris and the like. The grate is not intended to act as a dam to water.
As shown in FIG. 3, grate 13 is hinged at its top by hinge 20 so it can swing inwardly and upwardly as shown in FIG. 4. A frame 21 may conveniently be emplaced to hold the device.
An actuator 25 is suspended from end 26 of a lever 27 . The other end of lever 27 is hinged to the frame by hinge 28 . A pulley 29 is mounted to the frame to suspend and pass a flexible cable 30 . Cable 30 is attached to the free end of the grate, and to lever 27 (and thereby to the actuator).
The weight of the grate is sufficient to hold it closed against the torque exerted on it until there is sufficient weight of water in the actuator to overcome the weight of the grate itself. Additionally if preferred, a coil bias spring may be wound on the hinge 28 . Alternatively, lever 27 maybe spring-biased upwardly for the same purpose.
A preferred actuator 25 is shown in FIGS.7 and 8. It is an elongated trough having a pair of sidewalls 35 , 36 with a bleed port 37 at the bottom of the dihedral angle which they form. The width of the port determines the resistance to flow through it. End plates 38 close the structure. A dihedral screen 39 made of screen material excludes larger debris which might clog the bleed port. Much of what is caught on this screen will be washed away by a substantial flow of water.
As can be seen from FIG. 3, very slow water flow will simply drain down the wall of the chamber, or at least not reach the actuator. In FIG. 4, it is shown how flow 40 at a sufficient rate will reach the actuator, and if sufficient to fill the actuator (which is also draining to a sufficient level), its attained weight will draw the grate open and water will continue to flow into the actuator. The grate will close again when the flow of water into the actuator is slower than the drainage flow from it.
The simple arrangement of FIGS. 1-4 in uncomplicated, but does not resist being opened by direct force on the grate. The system of FIGS. 5-7 perform as in FIGS. 1-4, but include means to prevent the opening of the grate by forces exerted from the outside.
FIGS. 5-7 disclose a very useful feature. In the embodiment of FIGS. 1-4, a sufficient push on the grate will open it. It is useful to resist this event. For this purpose a toggle is provided which will hold the grate closed unless released by a force responsive to a sufficient weight on the actuator.
FIGS. 5 and 6 show an installation 50 in a curb 51 . The surrounding elements are identical and bear like numbers. Frame 52 hingedly supports grate 53 . An actuator 35 is suspended, but at the end of a different linkage. As before, a lever 54 has one end pivoted to the frame and its other to the actuator. Instead of a cable, a toggle linkage system 55 joins a midsection of lever 54 at pivot 55 a.
Toggle linkage system 55 includes a central link 56 hinged to the frame and a pair of toggle links 57 , 58 . A bias spring 60 biases central link 56 toward its locked position (FIG. 5 ). Link 58 is hinged to the grate.
Examination of FIG. 5 shows that the grate will be held closed against opening by a force exerted on it from the side by by the straight-line alignment of central link 56 and toggle link 58 . This toggle linkage will remain tight until the weight of the actuator overcomes the force of the bias spring and the weight of the grate itself, then it opens the toggle and the grate can open.
When the water retained in the actuator does reach the “critical” amount, the situation shown in FIG. 6 exists. Instead of a drip flow, or slow flow that does not reach the actuator, the flow 65 hits the actuator and water collects in it (less what drains from the drain port).
FIG. 7 illustrates the same system as in FIGS. 5 and 6, except that instead of a bias spring to drive the toggle system toward its locked condition, a weight 70 is attached to the central link, which exerts a constant force rather than a spring force to maintain the toggle lock. Otherwise the systems of FIGS. 5 and 7 are the same.
The operation of this system should be evident from the foregoing. The grate will be held closed to exclude trash and the like, but can pass the slow flow of water. When the rate of water flow becomes sufficient that it reaches out and fills the actuator the grate will be opened to pass whatever is presented to the opening where it is located.
This invention is not to be limited by the embodiments shown in the drawings and described in the description, which are given by way of example and not of limitation, but only in accordance with the scope of the appended claims. | A drain grate in an opening to a drain system which retains trash and debris upstream from the opening while permitting slow flow of water, and which opens completely when confronted with high rates of flow. | 4 |
FIELD OF THE INVENTION
The present invention relates to microwave (e.g. satellite) communication systems and is particularly directed to an arrangement for automatically tuning a cavity klystron to achieve a prescribed amplitude response.
BACKGROUND OF THE INVENTION
Klystrons are commonly employed as a basic signal source in microwave (e.g. satellite link) communication systems. As such, they are required to exhibit a prescribed output characteristic or amplitude response (e.g. flatness) over an operating bandwidth centered about a selected center frequency. Unfortunately, the tuning mechanism through which operation of the klystron is controlled is an extremely sensitive mechanism that does not offer the repeatability desired of signal control devices. Specifically, a klystron cavity tuner typically consists of a plurality of copper cavities and associated tuning slugs which are displaced back and forth in their respected cavities to establish the operational characteristics of the klystron. Usually, each slug is wrapped with a tungsten wire to assure a tight fit in its cavity. As tungsten is a considerably harder metal than copper, repeated movement of the tuning slug will wear down the wall of the cavity, thereby changing its dimensional tolerances and, consequently, its intended operational characteristics.
Because of the mutual interdependence of the tuning of the respective cavities, a klystron cannot be tuned by simply adjusting each tuning slug in an arbitrary order to a preestablished setting. Instead, control of the amplitude response of a klystron must be carried out by repeated back and forth adjustment of each tuning slug, through the use of a respective vernier (micrometer) adjustment knob for each slug, the rotational setting of which is graduated according to a prescribed tuning (number) chart. In a typical terminal environment, the klystron is housed in a protective equipment cabinet, access to the tuning elements of which is accomplished by way of a panel door. When tuning the klystron, the terminal operator rotates a roller chart to view the number settings to which the slug tuning knobs must be set, unlocks the knobs from their current positions, and then proceeds to tune the klystron, adjusting the knobs in a prescribed sequence and in accordance with the strict number settings of the tuning chart. If a setting is exceeded, even only slightly, the tuning adjustment must be backed off considerably and the procedure reinitiated which eliminates mechanical backlash. It may be appreciated, therefore, that errors in operator accuracy involving conventional mechanical adjustment mechanisms can add excessive tolerances to an already critical procedure. In fact, it has been found the amplitude response of a klystron tuned by two different operators under the same conditions will seldom be the same for both operators.
SUMMARY OF THE INVENTION
In accordance with the present invention, the effective non-repeatability of tuning cavity klystrons with conventional hand manipulated mechanical elements following a time consuming and considerably inexact "by-the-numbers" procedure is obviated by a processor-controlled drive motor system which monitors the output (amplitude-vs-frequency) of the klystron and compares that monitored performance output with an intended amplitude-vs-frequency profile. Differences between the two characteristics are employed by the processor to generate a set of tuning cavity control signals through which respective stepping motors for displacing each cavity tuning slug are driven. The processor iteratively adjusts the cavity tuner control signals in accordance with a prescribed klystron tuning program until the monitored amplitude response is within a prescribed tolerance of a preestablished characteristic stored in memory.
Because the tuning of the klystron is based upon monitoring its performance, rather than according to a "by-the-number" chart sequence, considerably improved accuracy of klystron operation over the operator-controlled approach is afforded. Moreover, because operator intervention is removed, human error is eliminated. In effect, the present invention assures repeatability of performance, over successive adjustments.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic block diagram of the processor-controlled klystron tuning system according to the present invention; and
FIGS. 2-5 depict exemplary klystron amplitude response characteristics for illustrating the operation of the tuning system of FIG. 1.
DETAILED DESCRIPTION
Before describing, in detail, the particular improved klystron cavity tuning scheme in accordance with the present invention, it should be observed that the present invention resides primarily in a novel structural combination of conventional signal processing and motor drive circuits and not in the particular detailed configurations thereof. Accordingly, the structure, control and arrangement of such conventional circuits have been illustrated in the drawings by readily understandable block representations and schematic diagram, which show only those specific details that are pertinent to the present invention, so as not to obscure the disclosure with structural details which will be readily apparent to those skilled in the art having the benefit of the description herein. In addition, various portions of the signal processing circuitry (including data processor) have been appropriately consolidated and simplified in order to emphasize those portions that are most pertinent to the present invention. Thus, the block diagram illustrations of the drawings do not necessarily represent the mechanical structural arrangement of the exemplary system, but are primarily intended to illustrate the major structural components of the system in a conventional functional grouping, whereby the present invention may be more readily understood.
Referring now to FIG. 1, there is shown a schematic block diagram of a cavity klystron tuning system in accordance with the present invention. In the exemplary embodiment, a klystron power amplifier 11, such as a VKX-7780F-1, five cavity klystron, manufactured by Varian, has its output coupled to an RF output microwave link 12. By way of a coupler 13, the RF output of the klystron 11 is coupled over link 14 to a digitally controlled spectrum analyzer 15 whereby the output of the klystron 11 may be monitored. For this purpose, spectrum analyzer 15 may comprise a Hewlett Packard 8566 RF spectrum analyzer which has an output (IEEE-488) data bus 17 for supplying all of the information pertaining to the RF signal on input link 14 being monitored. A pictorial illustration of an exemplary amplitude versus frequency of the output of the klystron as monitored by spectrum analyzer 15 is represented in FIG. 1 by the enlarged portion of the display screen 16 adjacent analyzer 15. The amplitude response data from the spectrum analyzer is coupled over data bus 17 to a processor 21 which operates, in effect, as a smart motor controller for operating an assembly 26 of tuning motors for the five cavities of the klystron. Processor 21 includes customary I/O buffer circuitry, central processing unit and associated memory in which the control program for operating the drive motors in accordance with the amplitude response as monitored by the spectrum analyzer 15 is stored. Output signals for controlling assembly 26 of drive motors for the cavities of the klystron are coupled over link 22 to a set of motor drive amplifiers 23. The outputs of amplifiers 23 are coupled over link 24 to stepping motor assembly 26 which contains (five) respective stepping motors for controlling the displacement of a set of drive rods or shafts 27 for the cavity tuning slugs of the klystron. In order to monitor the displacement of each of the drive shafts in response to the action of the stepping motors, a set of shaft position encoders 25 is provided. The output of each encoder 25 is coupled over link 27 to supply the processor 21 with an indication of the position of each shaft, and thereby the location of each tuning stub within the klystron cavity.
In operation, a tuning program, to be discussed below, for controlling stepping motors of the tuning motor assembly 26 and thereby the displacement of the tuning slug shafts 27 of the klystron, is loaded into memory of processor 21.
In order to properly tune each of the cavities to achieve the desired response, the correction program stored in memory of processor 21 is prepared using the instructions provided by the klystron manufacturer for each of the cavities of the klystron. The manufacturer will supply a data sheet indicating how displacement of the cavity tuner will effect the overall response produced by the tube. As an example, for the above-referenced klystron type VKX-7780F-1, manufactured by Varian, the following cavity response conditions are defined:
Cavity No. 1: displacement of the tuning stub to increase the frequency of the cavity will cause the output response of the klystron to tilt to the high end of the band; conversely, a decrease in frequency for the cavity will tilt the response of the klystron towards the lower end of the band;
Cavity No. 2: this cavity is initially tuned to broaden the response when going from high efficiency tuning to broad-band tuning. Once broad-band tuning is obtained, this cavity is employed to both broaden the response (primarily at the lower frequency end of the band) and to make adjustments for power output and gain;
Cavity No. 3: this cavity is initially used to broaden the response when going from the high efficiency tuning to broad-band tuning. When broad-banded, this cavity will affect the high end of the band. When tuned higher in frequency, the bandwidth at the high frequency end will increase with a slight reduction in power level at the high end of the band. This cavity is normally adjusted in conjunction with cavity No. 4. To compensate for the reduction in power output slightly when cavity No. 3 is increased in frequency, cavity No. 4 should be moved slightly lower in frequency;
Cavity No. 4: cavity No. 4 is initially used to obtain power when going from a synchronous tuning condition to a high frequency tuning condition. Once the tube has been broad-banded, the cavity will affect primarily the power level at the high frequency end of the response with a lesser effect on the bandwidth at the high end of the band;
Cavity No. 5: cavity No. 5 has effectively the same impact on the response output as cavity No. 1, except that it has a greater effect on the high frequency end of the response.
Given such a description of the functional effect of each cavity tuner for the particular klystron of interest, a control program is prepared to map its amplitude response into a sequence of control operations for each of the cavity tuners. In so doing, the control program stored in processor 21 continuously compares the output response of the klystron 11 as monitored by spectrum analyzer 15 with the intended characteristic contained in the program and uses differences between the two, namely the difference between sought-after and actual amplitude response, to drive the stepping motors for the respective cavity tuners.
As an illustration, consider the set of response curves shown in FIGS. 2-5 for the above-mentioned VKX-7780F-1 type klystron, which differ from a sought-after flat response symmetrically centered about a center frequency e.g. Fc=8.0 GHz.
Tuning of the klystron is initiated by a coarse tuning procedure wherein each of the cavity tuning drive motors of assembly 26 is caused to be rotated to a predetermined position corresponding to a prescribed frequency. As noted above, "coarse-tune" information is supplied from the klystron manufacturer, indicating an initial displacement of the tuning stubs for the frequency of interest. Using that information, the settings of the stepping motor encoders 25 are calibrated to provide the processor 21 with a reference position from which to start. As an example, considering the above-referenced center frequency of 8.0 GHz, the tuning shaft encoders for each of the five cavities of the klystron may correspond to the values: Cavity No. 1=30; Cavity No. 2=26; Cavity No. 3=31; Cavity No. 4=21; and Cavity No. 5=16.
The number of revolutions for each cavity tuner is determined by starting the count of the encoders 25 from a full counter-clockwise position (zero) or against the klystron mechanical stop for each tuning shaft 27. Whenever a klystron is inserted or replaced, the tuning shafts are tuned to zero to assure that each encoder's position correctly corresponds to that location. As a result, when the center frequency is to be changed, the tuners do not have to be returned to zero. Its associated encoder 25 indicates the relative position and starts, or remembers, the count from that point.
Having initially set the klystron tuner positions at the coarse locations provided by the manufacturer, klystron 11 is turned on to provide an initial or coarse output characteristic over line 14 to spectrum analyzer 15. In accordance with the program stored in processor 21, with the klystron now being coarse-tuned, the next step is to obtain the maximum output power from the klystron 11. This is achieved by step tuning each cavity. The tuning procedure stored in the memory of processor 21 begins with cavity No. 1, coupling a signal over link 24 to its associated drive motor 26 causing the motor to step in a prescribed direction. If the RF output power over link 12 increases from the klystron, processor 21 causes the drive motor to be stepped further in the same direction. On the other hand, if the output power had decreased, the motor is driven two steps in the opposite direction to cause a power increase. Once the output power of the klystron has increased 1 dB for the cavity of interest, processor 21 proceeds to the stepping motor for the next cavity, namely cavity No. 2 and carries out the same prodedure that it carried out for cavity No. 1. This process is repeated for all five cavities and then begins again at cavity No. 1, repeating the above procedure to increase the output power by an additional increment of 1 dB for each cavity. This iterative advance of the stepping motors 26 is carried out until maximum power, as monitored by spectrum analyzer 15 and processor 21, is achieved. Maximum power is recognized when the last step for the stepping motor for each cavity of interest causes a decrease in the output power. At this point, processor 21 steps the motor back to its previous position prior to the detected decrease in klystron output power.
Once maximum RF output power from klystron 11 has been established using the above sequence, spectrum analyzer 15 would detect an amplitude response curve on either side of the center frequency Fc=8.0 GHz. That characteristic is digitized and supplied to processor 21 over bus 17. The resultant pattern is compared in processor 21 with a desired characteristic, as stored in memory, and processor 21 next proceeds to adjust the cavity tuners (via stepping motor assembly 26) until the output characteristic), as monitored by spectrum analyzer 15 falls within a prescribed tolerance or threshold of the characteristic stored in memory of processor 21.
As examples of this operation, let it be assumed that the desired output amplitude response of klystron 11 is a flat response substantially equally distributed about some center frequency (e.g. Fc=8.0 GHz). FIG. 2 illustrates the condition in which there is a "glich" or "wrinkle" at the high end of the amplitude response. In this circumstance, the program stored in processor 21 causes the stepping motor for cavity No. 4 to be rotated in a direction which would slightly increase the frequency to flatten out the upper portion of the curve.
FIG. 3 shows an exemplary klystron response in which there is a hole or depression in the central part of the response at a small signal level. In this circumstance, the processor causes the stepping motor for cavity No. 1 to be rotated in a direction to increase the frequency, while that for cavity No. 2 is displaced to lower the frequency for that cavity.
The response in FIG. 4 illustrates an acceptable and flat response at the lower end of the bandwidth but an insufficiently large response at the high end of the bandwidth. In this circumstance, processor 21 drives the motor to displace the tuning rod for cavity No. 3 to a position causing a higher frequency for cavity No. 3 and a lower frequency for cavity No. 4.
FIG. 5 illustrates a response curve having a 40 MHz bandwidth but not equally centered on each side of the center frequency. In this case, processor 21 drives the stepping motors for all of the cavities to slightly increase the frequency until the curve shifts. Depending upon the resultant characteristic monitored by spectrum analyzer 15, further displacement of the drive shafts of the output of the stepping motors is conducted until the response curve is flattened and centered about the center frequency.
As will be appreciated from the foregoing description, the processor-controlled drive motor system of the present invention provides a mechanism for automatically and precisely tuning a cavity klystron that does not suffer from the cumbersome and inexact procedure conventionally employed by a terminal operator. By monitoring the amplitude vs frequency of the klystron as it is being tuned, the system of the present invention is able to adapt its iterative control procedure to rapidly bring the output characteristic to within a prescribed tolerance.
While I have shown and described an embodiment in accordance with the present invention, it is understood that the same is not limited thereto but is susceptible of numerous changes and modifications as known to a person skilled in the art, and I therefore do not wish to be limited to the details shown and described herein but intend to cover all such changes and modifications as are obvious to one of ordinary skill in the art. | A processor-controlled drive motor system for tuning a cavity klystron monitors the output (amplitude-vs-frequency) of the klystron and compares that monitored performance output with an intended amplitude-vs-frequency profile. Differences between the two characteristics are employed by the processor to generate a set of tuning cavity control signals through which respective stepping motors for displacing each cavity tuning slug are driven. The processor iteratively adjusts the cavity tuner control signals in accordance with a prescribed kylstron tuning program until the monitored amplitude response is within a prescribed tolerance of a preestablished characteristic stored in memory. | 7 |
FIELD OF THE INVENTION
The present invention relates to semiconductor device processing, and more particularly to a method of forming a semiconductor structure that includes at least multiple FinFET devices in which a single mask is used in defining the Fins, which avoids rounding of the corners where the Fins join the source/drain regions. The term “Fin” is used throughout this application to denote an elevated portion of a semiconducting layer of a semiconductor substrate that includes at least the device channel in which the width thereof is less than its height. The present invention is also related to the semiconductor structure including the multiple FinFET devices that is fabricated using the inventive method.
BACKGROUND OF THE INVENTION
The dimensions of semiconductor field effect transistors (FETs) have been steadily shrinking over the last thirty 30 years or so, as scaling to smaller dimensions leads to continuing device performance improvements. Planar FET devices have a conducting gate electrode positioned above a semiconducting channel, and electrically isolated from the channel by a thin layer of gate oxide. Current through the channel is controlled by applying voltage to the conducting gate.
For a given device length, the amount of current drive for an FET is defined by the device width (w). Current drive scales proportionally to device width, with wider devices carrying more current than narrower devices. Different parts of integrated circuits (ICs) require the FETs to drive different amounts of current, i.e., with different device widths, which is particularly easy to accommodate in planar FET devices by merely changing the device gate width (via lithography).
With conventional planar FET scaling reaching fundamental limits, the semiconductor industry is looking at more unconventional geometries that will facilitate continued device performance improvements. One such class of devices is a FinFET.
A FinFET is a double gate FET in which the device channel is within a semiconducting “Fin” having a width w and height h, where typically w<h. The gate dielectric and gate are positioned around the Fin such that charge flows down the channel on the two sides of the Fin and optionally along the top surface.
FinFET devices typically include a fully depleted body in the Fin that provides several advantages over a conventional FET. These advantages include, for example, nearly ideal turn off in the sub-threshold regime, giving lower off-currents and/or allowing lower threshold voltages, no loss to drain currents from body effects, no ‘floating’ body effects (often associated with some silicon-on-insulator (SOI) FETs), higher current density, lower voltage operation, and reduced short channel degradation of threshold voltage and off current. Furthermore, FinFETs are more easily scaled to smaller physical dimensions and lower operating voltages than conventional FETs and SOI FETs.
Definition of both the semiconducting Fins and the source/drain regions by a single mask has been extremely difficult in the prior art due to rounding of the corners where the Fins join the wide source/drain areas. As a result, there is neither room for alignment of the gate to the active semiconducting material, nor room for extension implants into the sidewalls of the Fins.
A mask to separately pattern source and drain regions of silicon to link the Fins provides a solution for the rounding problem, but adds an extra overlay for added mask to the Fins, leaving little room for extension implants between the source and drain linking regions and the gate electrode, unless the registration of the various masks is nearly perfect.
In view of the above, there is a need for providing a method that can define both the Fins and the source/drain regions by a single mask that avoids the rounding problem mentioned above as well as the need for using additional overlays.
SUMMARY OF THE INVENTION
The present invention provides a method that overcomes the above mentioned problems using simple rectangular shapes to define the Fins which avoid rounding and yet joins the Fins by a deposition of a selective silicon-containing material post gate etch. More specifically, the present invention provides a method of forming a semiconductor structure including a plurality of FinFET devices in which crossing masks are employed in providing linear patterns to define relatively thin Fins along with a chemical oxide removal (COR) process. The present method further includes a step of merging adjacent Fins by the use of a selective silicon-containing material.
In general terms, the present invention provides a method that includes the steps of:
providing a structure including a plurality of patterned material stacks comprising a nitride layer on top of an oxide hardmask on a surface of semiconductor substrate and a plurality of patterned photomasks which cross over said plurality of patterned material stacks;
performing a chemical oxide removal step that laterally etches at least exposes sidewalls of said oxide hardmask of each material stack not protected by one of said patterned photomasks;
removing the plurality of patterned photomasks to expose patterned material stacks including a laterally etched oxide hardmask beneath said nitride layer;
performing an anisotropic etching process selective to the laterally etched oxide hardmask to remove said nitride layer and at least an upper portion of any semiconducting material of said semiconductor substrate not protected by said laterally etched oxide hardmask to form Fins; and
forming a plurality of gate regions that cross over said Fins.
Optionally, the laterally etched oxide hardmask is removed by exposing upper portions of the semiconducting material of the semiconductor substrate previously protected by said laterally etched oxide hardmask, wherein portions of said exposed upper portions of the semiconducting material of the semiconductor substrate previously protected by said laterally etched oxide hardmask define the Fins.
Each of the Fins produced by the inventive method are then merged by forming a Si-containing material between each of the Fins. The Si-containing material prevents rounding of corners of each Fin with their corresponding source/drain region. The source/drain regions are located within wider end portions of each Fin that where previously protected by said plurality of patterned masks that cross over said plurality of patterned stacks. The wider end portions of each Fin are substantially square; i.e., little or no rounding of the corners of the wider end portions occurs in the present invention.
The present invention also relates to the semiconductor structure that is fabricated using the above processing steps. In general terms, the semiconductor structure of the present invention comprises:
a plurality of FinFET devices located on a surface of a semiconductor substrate, each of said FinFET devices including an elevated semiconducting layer that has wider end portions relative to its middle portion, a gate region that crosses said middle portion, and source/drain regions within said wider end portions; and
a Si-containing material located between said elevated semiconducting layer that joins each elevated semiconducting layer.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1A is a pictorial representation (through a top-down view) and FIG. 1B is a pictorial representation (through a cross-sectional view) showing a plurality of first patterned photomasks located over a structure including (from bottom to top) a semiconductor substrate, an oxide hardmask and a nitride layer.
FIG. 2 is a pictorial representation (through a top-down view) showing the structure of FIG. 1 after etching exposed regions of the nitride layer and the oxide layer stopping on an upper surface of the semiconductor substrate, removing the plurality of first patterned photomasks and forming a plurality of second patterned photomasks that lay across stripes of stacked oxide/nitride layers.
FIG. 3 is a pictorial representation (through a top-down view) showing the structure of FIG. 2 after performing a chemical oxide removal (COR) process which etches exposed sidewalls of the oxide hardmask to a desired distance undercutting both the nitride layer and the second patterned photoresist masks by the distance.
FIG. 4 is a pictorial representation (through a top-down view) showing the structure of FIG. 3 after removing the second patterned photoresist masks; an undercut oxide layer pattern is illustrated, although cover by the nitride layer.
FIG. 5 is a pictorial representation (through a top-down view) showing the structure of FIG. 4 after performing an anisotropic etch that is selective to the oxide layer, stopping within the semiconductor substrate, e.g., on a buried insulator layer within the substrate.
FIG. 6 is a pictorial representation (through a top-down view) showing the structure of FIG. 5 after forming a gate region including a gate dielectric and a gate electrode.
FIG. 7 is a pictorial representation (through a top-down view) showing the structure of FIG. 6 after spacer formation.
FIG. 8 is a pictorial representation (through a top-down view) showing the structure of FIG. 7 after selectively forming a Si-containing layer on exposed sidewalls of the substrate.
DETAILED DESCRIPTION OF THE INVENTION
The present invention, which provides a method of fabricating a semiconductor structure that includes at least multiple FinFET devices in which a single mask is used in defining the Fins as well as the resultant semiconductor structure, will now be described in greater detail by referring to the following discussion and drawings that accompany the present application. It is noted that the drawings of the present application are provided for illustrative purposes and, as such, they are not drawn to scale.
Reference will be made to FIGS. 1-8 which illustrate an embodiment in which a semiconductor-on-insulator (SOI) substrate is used. Although an SOI substrate is depicted and described in the following discussion, the present invention also contemplates utilizing a bulk semiconductor substrate. When a bulk semiconductor substrate is used, the bulk semiconductor substrate comprises one of Si, Ge alloys, SiGe, GaAs, InAs, InP, SiCGe, SiC as well as other III/V or II/VI compound semiconductors. Preferably, and when a bulk semiconductor is employed, the substrate includes a Si-containing semiconducting material, with Si being highly preferred.
As indicated above, the processing description provided herein utilizes an SOI substrate. An SOI substrate includes a bottom semiconductor layer and a top semiconductor layer (i.e., active semiconductor layer) that are electrically isolated from each other by a buried insulating layer. The top and bottom semiconductor layers may comprise one of the above mentioned bulk semiconductor materials, with Si-containing semiconductors, preferably, Si being highly preferred. The buried insulating material separating the two semiconducting layers may be a crystalline or non-crystalline oxide or nitride, with crystalline oxides being highly preferred. It is noted that SOI substrates are preferred over bulk substrates since they permit formation of devices having higher operating speeds. In particular, devices formed using SOI technology provide higher performance, absence of latch-up, higher packaging density and low voltage applications as compared with their bulk semiconductor counterparts.
The SOI substrate employed in the present invention may be formed utilizing conventional processing techniques well known in the art. For example, a layer transfer process including a bonding step can be used in providing the SOI substrate. Alternatively, an implantation process such as SIMOX (Separation by IMplantation of OXygen) can be used in forming the SOI substrate.
The thickness of the various layers of the SOI substrate may vary depending on the technique used in forming the same. Typically, however, the top semiconductor layer has a thickness from about 3 to about 100 nm, the buried insulating layer has a thickness from about 10 to about 150 nm, and the thickness of the bottom semiconductor layer of the SOI substrate is inconsequential to the present invention.
Reference is now made to FIG. 1B which is a pictorial representation (through a cross-sectional view) showing a plurality of first patterned photomasks 22 located over a structure 100 including (from bottom to top) an SOI semiconductor substrate 10 , an oxide hardmask 18 and a nitride layer 20 . As stated above, the SOI substrate 10 includes a bottom semiconductor layer 12 , a buried insulating layer 14 and a top semiconductor layer 16 . A top-down view of structure 100 is shown in FIG. 1A . In the top-down views provided in the present application, only the patterned regions are highlighted.
The structure 100 is formed by first providing an SOI substrate (or bulk semiconductor substrate) by conventional techniques. Next, the oxide hardmask 18 is formed on the upper surface of the substrate, e.g., the upper surface of the top semiconductor layer 16 , utilizing a conventional deposition process such as, for example, chemical vapor deposition (CVD), plasma enhanced chemical vapor deposition (PECVD), atomic layer deposition (ALD), physical vapor deposition (PVD), evaporation, chemical solution deposition and other like deposition processes. Alternatively, the oxide hardmask 18 is formed utilizing a conventional oxidation process. The thickness of the oxide hardmask 18 formed at this point of the present invention may vary depending on the technique that was used in forming the same. Typically, the thickness of the oxide hardmask 18 employed in the present invention is from about 1 to about 50 nm, with a thickness from about 2 to about 30 nm being even more typical.
Following the formation of the oxide hardmask 18 , a nitride layer 20 such as Si 3 N 4 is formed atop the oxide hardmask 18 . The nitride layer 20 can be formed utilizing a conventional deposition process such as CVD, PECVD, ALD, PVD, evaporation, chemical solution deposition or and other like deposition processes. Alternatively, the nitride layer 20 is formed utilizing a conventional nitridation process. The thickness of the nitride layer 20 formed at this point of the present invention may vary depending on the technique that was used in forming the same. Typically, the thickness of the nitride layer 20 employed in the present invention is from about 1 to about 20 nm, with a thickness from about 1.5 to about 4 nm being even more typical.
After nitride layer 20 formation, a blanket layer of photoresist material is deposited on the surface of the nitride layer 20 utilizing a conventional deposition process such as, for example, CVD, PECVD, evaporation or spin-on coating. The blanket layer of photoresist material is patterned into a plurality of first patterned photomasks 22 as shown in FIGS. 1A and 1B . Patterning of the photoresist material is achieved by utilizing a conventional lithographic process which includes exposing the photoresist material to a pattern of radiation and developing the exposed photoresist material utilizing a conventional resist developer.
To better highlight the inventive method, the fabrication process will make reference to top-down views from now on. With the plurality of first patterned photomasks 22 in place, the exposed nitride layer 20 and the underlying oxide hardmask 18 are removed from the structure 100 utilizing one or more etching processes. The one or more etching processes remove the unprotected portions of layers 20 and 18 , stopping on an upper surface of the SOI substrate 10 , i.e., atop the top semiconductor layer 16 . The one or more etching processes may include dry etching or wet etching. Preferably, dry etching such as reactive-ion etching (RIE) is used. Other examples of dry etching that can be used at this point of the present invention include ion beam etching, plasma etching or laser ablation.
After the one or more etching processes have been performed, the plurality of first patterned photomasks 22 are removed utilizing a conventional resist stripping process. The structure at this point of the present invention includes a plurality of material stacks 24 containing remaining portions of nitride layer 20 and oxide hardmask 18 on the SOI substrate 10 .
A plurality of second photomasks 26 is then formed so as to cross stripes of material stacks 24 . That is, the plurality of second photomasks 26 is formed such that each of the second photomasks 26 lay across the material stacks 24 . The plurality of second photomasks 26 are formed by first applying a second blanket photoresist material to the structure shown in FIGS. 1A and 1B and then subjecting that blanket photoresist layer to lithography. The area between the second photomasks, particularly the underlying top semiconductor layer 16 of the SOI substrate 10 , represents the location wherein the Fins of each FinFET device will be formed.
The structure including the plurality of second photomasks 26 and the material stacks 24 is shown in FIG. 2 . Note, that the plurality of second photomasks 26 protect some portions of the material stacks 24 as well as the adjacent SOI substrate 10 , e.g., the top semiconductor layer 18 .
The resultant structure shown in FIG. 2 is then subjected to a chemical oxide removal (COR) process. The COR process selectively etches (in a lateral direction) exposed vertical surfaces of the oxide hardmask 18 of each material stack 24 undercutting both the overlying nitride layer 20 and each of the second photomasks 26 . The lateral etch is performed to a predetermined distance of from about 5 to about 40 nm, which distance is substantially the same for the undercuts as well. FIG. 3 shows the structure after the COR process. Note that in FIG. 3 and FIG. 4 the pattern formed in the underlying oxide hardmask 18 is shown to emphasize the COR processing step of the present invention. Although the patterned oxide hardmask 18 is shown in these drawings of the present invention, nitride layer 20 remains atop the patterned hardmask 18 at these two stages of the present invention.
The COR process used in providing the structure shown in FIG. 3 comprises exposing the structure of FIG. 2 to a gaseous or vaporous mixture of HF and ammonia at a pressure of about 30 mTorr or below, preferably at a pressure from about 1 mTorr to about 30 mTorr. The COR process is typically performed at a temperature that is about nominal room temperature (20° C. to about 40° C.), with a temperature of about 25° C. being even more typical. The ratio of HF to ammonia employed in the COR process is typically from about 1:10 to about 10:1, with a ratio of about 2:1 being even more typical.
After performing the COR process, the plurality of second photomasks 26 are removed from the structure utilizing a conventional resist stripping processing step. FIG. 4 shows the resultant structure that is formed after the plurality of second photomasks 26 are removed from the structure. In this drawing, the undercut oxide layer 18 is again illustrated, although covered by nitride layer 20 .
An anisotropic Si etch, selective to the remaining oxide hardmask 18 , is used to remove the remaining nitride layer 20 as well as exposed top semiconductor layer 16 of SOI substrate 10 , stopping on buried insulating layer 14 . When a bulk substrate is used, this etch thins the substrate to a predetermined value. An example of an anisotropic Si etch that can be used at this point of the present invention includes reactive-ion etching with a fluorocarbon chemistry, such as CF 4 . The resultant structure is shown, for example, in FIG. 5 . In FIG. 5 , oxide hardmask 18 remains, and buried insulating layer 14 is exposed. It is emphasized that the top semiconductor layer 16 underlying the patterned oxide hardmask 18 will now have the same pattern as layer 18 .
The remaining oxide hardmask 18 can be removed in one embodiment, in which case the top surface of the Fin will become part of the FinFET channel once the structure is complete. Specifically, an etching process selective to the semiconducting material can be used to optionally remove the remaining oxide hardmask 18 . In the drawings, the remaining oxide hardmask 18 is shown as being removed from the structure. Although this is illustrated, the present invention also contemplates embodiments where the remaining oxide hardmask 18 remains in the structure during the following processing steps.
In some embodiments of the present invention, the patterned semiconductor layer 16 may need to be ion implanted at this point of the present invention. When ion implantation is needed, a conventional ion implantation process can be used to implant dopant ions (p- or n-type) into the patterned top semiconducting layer 16 .
FIG. 6 shows the structure of FIG. 5 forming a gate region 28 that includes a gate dielectric (not shown in this drawing of the present invention) and an overlying gate electrode 30 . The gate dielectric is formed first, followed by the gate electrode. Specifically, the gate dielectric is formed by first providing a sacrificial oxide (not shown) on the structure and then stripping the sacrificial oxide to remove imperfections in the structure. The gate dielectric is then formed by a thermal growth process such as, for example, oxidation, nitridation or oxynitridation. Alternatively, the gate dielectric can be formed by a deposition process such as, for example, chemical vapor deposition (CVD), plasma-assisted CVD, metalorganic chemical vapor deposition (MOCVD), atomic layer deposition (ALD), evaporation, reactive sputtering, chemical solution deposition and other like deposition processes. The gate dielectric may also be formed utilizing any combination of the above processes.
The gate dielectric is comprised of an insulating material having a dielectric constant of about 4.0 or greater, preferably greater than 7.0. The dielectric constants mentioned herein are relative to a vacuum. Note that SiO 2 typically has a dielectric constant that is about 4.0. Specifically, the gate dielectric employed in the present invention includes, but is not limited to: an oxide, nitride, oxynitride and/or silicates including metal silicates, aluminates, titanates and nitrides. In one embodiment, it is preferred that the gate dielectric is comprised of an oxide such as, for example, SiO 2 , HfO 2 , ZrO 2 , Al 2 O 3 , TiO 2 , La 2 O 3 , SrTiO 3 , LaAlO 3 , Y 2 O 3 and mixture thereof.
The physical thickness of the gate dielectric may vary, but typically, the gate dielectric has a thickness from about 1 to about 10 nm, with a thickness from about 1 to about 3 nm being more typical.
After forming the gate dielectric, a blanket layer of a conductive material which forms the gate electrode 30 of gate region 28 is formed on the gate dielectric utilizing a known deposition process such as physical vapor deposition (PVD), CVD or evaporation. The conductive material may comprise polysilicon, SiGe, a silicide, a metal or a metal-silicon-nitride such as Ta—Si—N. Examples of metals that can be used as the conductive material include, but are not limited to: Al, W, Cu, Ti or other like conductive metals. The blanket layer of conductive material may be doped or undoped. If doped, an in-situ doping deposition process may be employed. Alternatively, a doped conductive material can be formed by deposition, ion implantation and annealing.
The doping of the conductive material will shift the workfunction of the gate formed. Illustrative examples of doping ions include As, P, B, Sb, Bi, In, Al, TI, Ga or mixtures thereof. The thickness, i.e., height, of the conductive material deposited at this point of the present invention may vary depending on the deposition process employed. Typically, the conductive material has a vertical thickness from about 20 to about 180 nm, with a thickness from about 40 to about 150 nm being more typical.
In some embodiments, an optional hardmask (not shown) may be formed atop the conductive material utilizing a conventional deposition process. The optional hardmask can be comprised of a dielectric such as an oxide or nitride.
After deposition of at least the gate dielectric and the conductive material, gate regions 28 including gate electrode 30 are formed. Specifically, the gate regions 28 are formed by first providing a patterned mask atop the conductive material by deposition and lithography and then transferring the pattern to the conductive material and optional the gate dielectric. The etching steps comprise one or more etching processes including dry etching such as RIE. It is noted that the region of patterned semiconductor 16 in which the gates cross over is the channel region of the Fin. The Fin is an elevated semiconductor layer 16 that includes wider end portions connected by a thinner middle portion as is shown in FIGS. 6-8 . It is observed that the patterned semiconductor layer 16 has a dumb bell or dog bone shape in which the outer, wider end portions are substantially square due to the processing steps of the present invention.
Next, source/drain extension regions (not shown) and/or halo regions (not shown) are formed into the semiconductor substrate utilizing conventional implantation processes well known to those skilled in the art.
Next, a gate spacer 32 comprising an oxide, nitride, oxynitride or combination thereof is formed around the perimeter of the gate region 28 as is shown, for example, in FIG. 7 . The gate spacer 32 is formed by a conventional deposition process such as, for example, CVD or PECVD, followed by a directional etching process. It is noted that the gate dielectric is shown in this drawing and FIG. 8 to illustrate its position relative to the channel portion of the Fin; reference numeral 29 denotes the gate dielectric surrounding the channel position of the Fin.
Next, and as shown in FIG. 8 , a single crystalline Si-containing material 34 such as Si, SiGe or SiGeC is selectively grown from the exposed sidewalls of the top semiconductor layer 16 of the SOI substrate 10 . The single crystalline Si-containing material 34 is formed by CVD, PECVD or an UHVCV process. Source/drain regions (the term ‘S/D ’ is used in FIG. 8 to represent the location of the source/drain regions) are then implanted into wider portion of the semiconductor material 16 adjoining each Fin utilizing conventional ion implantation techniques well known in the art.
The above processing steps provide a semiconductor structure such as shown in FIG. 8 that includes at least multiple FinFET devices 102 in which a single mask is used in defining the Fins 104 which avoids rounding of the corners where the Fins 104 join the source/drain regions.
While the present invention has been particularly shown and described with respect to preferred embodiments thereof, it will be understood by those skilled in the art that the foregoing and other changes in forms and details may be made without departing from the spirit and scope of the present invention. It is therefore intended that the present invention not be limited to the exact forms and details described and illustrated, but fall within the scope of the appended claims. | A method of forming a semiconductor structure including a plurality of finFFET devices in which crossing masks are employed in providing a rectangular patterns to define relatively thin Fins along with a chemical oxide removal (COR) process is provided. The present method further includes a step of merging adjacent Fins by the use of a selective silicon-containing material. The present invention also relates to the resultant semiconductor structure that is formed utilizing the method of the present invention. | 7 |
The enclosed application is based on Provisional Patent Application Ser. No. 60/179,423 filed Jan. 31, 2000. Applicants claim the benefit of the filing date of the aforesaid Provisional Application under 35 U.S.C. §119(e)(1).
SCOPE OF THE INVENTION
The present invention relates to thienopyranecarboxamide derivatives, to pharmaceutical compositions containing them and to uses for such derivatives and compositions.
BACKGROUND OF THE INVENTION
U.S. Pat. No. 5,403,842, Leonardi et al., and its continuations in part (U.S. Pat. Nos. 5,474,994 and 5,605,896) claim heterobicyclic derivatives bearing substituted phenylpiperazines as basic moieties linked to the heterocyclic ring by a variety of spacer groups. Among said derivatives, compound A (Ex. 11) is of relevant interest due its very high uroselective activity.
Compound A is endowed with good affinity for the α 1A adrenoceptor and is able to selectively inhibit contractility of the prostatic urethra in a dog model without substantial effects on blood pressure (Leonardi et al., J. Pharmacol. Exp. Therap., 281:1272-1283, 1997.)
7-Oxo-7H-thieno[3,2-b]pyran-3-carboxylic acid and its N,ω-aminoalkylamides are compounds not yet reported in the literature. The present invention is directed to the new structural class of the N-(substituted phenyl)-N′-[ω-(5-substituted-7-oxo-7H-thieno[3,2-b]pyran-3-carbonylamino)alkyl]piperazines.
Compounds of this class are endowed with enhanced selectivity toward the α 1 adrenergic receptor (with or without further selectivity for the α 1A receptor or for both α 1A and α 1D ), in particular with respect to the 5-HT 1A receptor, and improved in vivo uroselectivity even compared to compound A, with remarkable effects on relaxation of prostatic urethra and very low activity in lowering blood pressure. This activity profile suggests the safer use of the compounds of the invention in the therapy of obstructive syndromes of the lower urinary tract, including benign prostatic hyperplasia (BPH), and of lower urinary tract symptoms (LUTS) as well as of neurogenic lower urinary tract dysfunction (NLUTD), without side-effects associated with hypotensive activity.
SUMMARY OF THE INVENTION
In one aspect, the invention is directed to compounds of Formula I:
wherein
R is an aryl, cycloalkyl or polyhaloalkyl group,
R 1 is chosen from the group consisting of alkyl, alkoxy, polyfluoroalkoxy, hydroxy and trifluoromethanesulfonyloxy; each of R 2 and R 3 independently is chosen from the group consisting of a hydrogen, halogen, alkoxy and polyfluoroalkoxy group, and n is 0, 1 or 2.
The preferred aryl group which R may represent without limitation is phenyl. The preferred cycloalkyl group that R may represent without limitation is cyclohexyl. The preferred polyhaloalkyl group that R may represent without limitation is trifluoromethyl. The preferred alkyl group which R 1 may represent without limitation is C 1-4 lower alkyl. Preferred alkoxy groups (C 1-4 ) which R 1 , R 2 , and R 3 may represent without limitation are lower alkoxy groups, most preferably methoxy. Preferred polyfluoroalkoxy which R 1 , R 2 , and R 3 may represent without limitation are trifluoromethoxy or 2,2,2-trifluoroethoxy.
The preferred value for n is 1.
Also preferred is where R 1 is chosen from the group consisting of alkoxy and hydroxy; R 2 is chosen from the group consisting of hydrogen and halogen; R 3 is chosen from the group consisting of hydrogen and halogen; and n is 0, 1 or 2.
Also preferred is where R 1 is chosen from a group consisting of alkoxy, hydroxy and polyfluoroalkoxy; R 2 is chosen from the group consisting of hydrogen, halogen and alkoxy; R 3 is chosen from the group consisting of hydrogen, halogen and alkoxy; and n is 0, 1 or 2.
Also preferred is where R 1 is chosen from the group consisting of alkoxy, polyfluoroalkoxy, hydroxy; R 2 is halogen; R 3 is hydrogen; and n is 0, 1 or 2.
The invention also includes the N-oxides and pharmaceutically acceptable salts of these compounds.
The invention further provides pharmaceutical compositions comprising a compound of Formula I or a N-oxide or pharmaceutically acceptable salt of such a compound in admixture with a pharmaceutically acceptable diluent or carrier.
In another aspect, the present invention is directed to methods for selectively preventing contractions (including noradrenaline-mediated contractions) of the urethra and lower urinary tract, without substantially affecting blood pressure, by administering one or more selected compounds of Formula I to a mammal (including a human) in need of such treatment in an amount or amounts effective for the particular use.
In yet another aspect, the invention is directed to methods for blocking a, receptors, by delivering to the environment of said receptors, e.g., to the extracellular medium, (or by administering to a mammal possessing said receptors) an effective amount of a compound of the invention, in this way relieving diseases associated to overactivity of said receptors.
The very high uroselectivity of the compounds of this invention has been tested in the dog model described in Example 10, where their efficacy in antagonizing the contractions of prostatic urethra in the presence of very limited effects on blood pressure has been shown, in comparison to compound A and to another well-known α 1 -antagonist, prazosin.
Accordingly, it is a primary object of the present invention to provide a method of treating BPH which avoids any undue side effects due to acute hypotension (i.e., limited effects on blood pressure).
It is another object of the present invention to provide pharmaceutical compositions comprising 7-oxo-7H-thieno[3,2-b]pyran compounds which are selective a, adrenoceptor antagonists, which compositions are effective for the treatment of BPH optionally including a carrier or diluent.
It is another object of the present invention to provide a method of treating BPH using 7-oxo-7H-thieno[3,2-b]pyran compounds which are selective α 1 adrenoceptor antagonists.
Another aspect of the invention is the use of new compounds for lowering intraocular pressure, inhibiting cholesterol synthesis, reducing sympathetically-mediated pain, the treatment of cardiac arrhythmia and erectile dysfunction, as well as treatment of LUTS and NLUTD.
An object of the present invention is to provide a method of preventing contractions of the urethra and lower urinary tract comprising administering to a mammal including a human in need of such treatment an effective amount of compounds of the present invention and/or pharmaceutical compositions comprising compounds of the present invention.
A further object of the present invention is a method of administration of compounds of the present invention or pharmaceutical compositions comprising compounds of the present invention to mammals including humans which causes very limited effects on the blood pressure of said mammal.
A further object of the present invention is a method for blocking a, adrenergic receptors comprising releasing in the environment of said receptors compounds of the present inventions or pharmaceutical compositions of the present invention to relieve diseases associated with overactivity of said receptor.
A further object of the present invention is the release of compounds of the present invention or pharmaceutical compositions containing compounds of the present invention in the environment of α 1 adrenergic receptors wherein said release is effected by administering compounds of the present invention or pharmaceutical compositions containing compounds of the present invention to a mammal including a human possessing said receptors.
A further object of the present invention is the method of treatment of a patient suffering from benign prostatic hyperplasia, the method comprising administering an effective amount of a compound of the present invention or a pharmaceutical composition containing a compound of the present invention to a patient in need of such treatment.
A further object of the present invention is the method of treatment of a patient suffering from excessive intraocular pressure, the method comprising administering an effective amount of a compound of the present invention or a pharmaceutical composition containing a compound of the present invention to a patient in need of such treatment.
A further object of the present invention is the method of treatment of a patient suffering from cardiac arrhythmia, the method comprising administering an effective amount of a compound of the present invention or a pharmaceutical composition containing a compound of the present invention to a patient in need of such treatment.
A further object of the present invention is the method of treatment of a patient suffering from erectile dysfunction, the method comprising administering an effective amount of a compound of the present invention or a pharmaceutical composition containing a compound of the present invention to a patient in need of such treatment.
A further object of the present invention is the method of treatment of a patient suffering from sexual dysfunction, the method comprising administering an effective amount of a compound of the present invention or a pharmaceutical composition containing a compound of the present invention to a patient in need of such treatment.
A further object of the present invention is the method for inhibiting cholesterol synthesis, the method comprising administering an effective amount of a compound of the present invention or a pharmaceutical composition containing a compound of the present invention to a patient in need of such treatment.
A further object of the present invention is the method for reducing sympathetically mediated pain, the method comprising administering an effective amount of a compound of the present invention or a pharmaceutical composition containing a compound of the present invention to a patient in need of such treatment.
A further object of the present invention is the method for the treatment of lower urinary tract symptoms (LUTS), which include but are not limited to filling symptoms, urgency, incontinence and nocturia, as well as voiding problems such as weak stream, hesitance, intermittency, incomplete bladder emptying and abdominal straining, the method comprising administering an effective amount of a compound of the present invention or a pharmaceutical composition containing a compound of the present invention to a patient in need of such treatment, optionally further comprising the inclusion of an anticholinergic compound which may be selected from the group consisting of tolterodine, oxybutinin, darifenacin, alvameline and temiverine.
A further object of the present invention is the method for the treatment of neurogenic lower urinary tract dysfunction (NLUTD), the method comprising administering an effective amount of a compound of the present invention or a pharmaceutical composition containing a compound of the present invention to the patient, optionally further comprising the inclusion of an anticholinergic compound which may be selected from the group consisting of tolterodine, oxybutinin, darifenacin, alvameline and temiverine.
A further object of the present invention is the treatment of LUTS in females which include but are not limited to filling symptoms, urgency, incontinence, and nocturia as well as voiding problems such as weak stream, hesitance, intermittency, incomplete bladder emptying, and abdominal straining, the method comprising administering an effective amount of a compound of the present invention or a pharmaceutical composition containing a compound of the present invention to a woman in need of such treatment, optionally further comprising the inclusion of an anticholinergic compound which may be selected from the group consisting of tolterodine, oxybutinin, darifenacin, alvameline and temiverine
Other features and advantages of the present invention will be apparent to those skilled in the art from the following detailed description and claims.
DETAILED DESCRIPTION OF THE INVENTION
All patents, patent applications and literature references cited in this application are incorporated by reference in their entirety.
The adrenergic antagonistic activity of the compounds of the invention renders them useful as agents acting on body tissues particularly rich in α 1 -adrenergic receptors (such as prostate and urethra). Accordingly, the anti-adrenergic compounds within the invention, established as such on the basis of their receptor binding profile, can be useful therapeutic agents for the treatment, for example, of micturition problems associated with obstructive disorders of the lower urinary tract, including but not limited to benign prostatic hypertrophy (BPH).
BPH is a progressive condition, which is characterised by a nodular enlargement of prostatic tissue resulting in obstruction of the urethra. This results in increased frequency of urination, nocturia, a poor urinary stream and hesitancy or delay in starting urine flow. Chronic consequences of BPH can include hypertrophy of bladder smooth muscle, a decompensated bladder and an increased incidence of urinary tract infection. The specific biochemical, histological and pharmacological properties of a prostate adenoma leading to the bladder outlet obstruction are not yet known. However, the development of BPH is considered to be an inescapable phenomenon for the ageing male population. BPH is observed in approximately 70% of males over the age of 70. Currently, the worldwide stated method of choice for treating BPH is surgery. A medicinal alternative to surgery is clearly very desirable. The limitations of surgery for treating BPH include the morbidity rate of an operative procedure in elderly men, persistence or recurrence of obstructive and irritative symptoms, as well as the significant cost of surgery.
α-Adrenergic receptors (McGrath et al., Med. Res. Rev., 9:407-533, 1989) are specific neuroreceptor proteins located in the peripheral and central nervous systems on tissues and organs throughout the body. These receptors are important switches for controlling many physiological functions and, thus, represent important targets for drug development. In fact, many α-adrenergic drugs have been developed over the past 40 years. Examples include clonidine, phenoxybenzamine and prazosin, terazosin, alfuzosin, doxazosin, tamsulosin (treatment of hypertension), naphazoline (nasal decongestant), and apraclonidine (treating glaucoma). α-Adrenergic drugs can be broken down into two distinct classes: agonists (clonidine and naphazoline are agonists), which mimic the receptor activation properties of the endogenous neurotransmitter noradrenaline, and antagonists (phenoxybenzamine and prazosin, terazosin, alfuzosin, doxazosin, tamsulosin are antagonists), which act to block the effects of noradenaline. Many of these drugs are effective, but also produce unwanted side effects (for example, clonidine produces dry mouth and sedation in addition to its antihypertensive effects).
The above reported agonists are selective for the α 2 adrenergic receptor whereas most antagonists are selective for the α 1 adrenoceptor, with the exception of tamsulosin which shows a relevant affinity also for the 5-HT 1A receptor. Many of the cited α 1 antagonists are currently used for the therapy of BPH but, due to their poor uroselectivity, they are liable to cause side effects of cardiovascular type.
Recent pharmacological, biochemical and radioligand-binding studies evidenced three different α 1 -receptor subtypes with a high affinity for prazosin, namely α 1A- (α 1a- ), α 1B- (α 1b- ) and α 1D- (α 1d- ), with lower case subscripts being used for recombinant receptors and upper case subscripts for receptors in native tissues (Hieble et al., Pharmacol. Rev., 47:267-270, 1995). In functional studies α 1 -receptors with a low affinity for prazosin have also been identified and termed α 1L -receptors (Flavahan and Vanhoutte, Trends Pharmacol. Sci., 7:347-349, 1986; Muramatsu et al., Pharmacol. Comm., 6:23-28, 1995).
Several studies have demonstrated the presence of these α 1 -adrenergic receptor subtypes in the lower-urinary-tract tissues as reviewed by (Andersson, K. E., “4th International Consultation in Benign Prostatic Hyperplasia (BPH)”, Paris, Jul. 2-5, 1997, pages 601-609).
Several studies have shown that the human prostate receives innervation from both the sympathetic and parasympathetic nervous systems.
The adrenergic nerves are considered responsible for prostatic smooth-muscle tone by releasing noradrenaline, stimulating contraction-mediating α-adrenoceptors. Approximately 50% of the total urethral pressure in BPH patients may be due to α-adrenoceptor-mediated muscle tone. Functional studies have indicated the occurrence of important adrenoceptor functions in prostatic adenomatous and capsular tissue. Clinical studies with the prototypical adrenoceptor-selective antagonist, prazosin, reinforced the key role of α 1 adrenoceptors in the control of prostatic smooth-muscle tone. This was also confirmed in the laboratory by studies showing that, although both α 1- and α 2 -adrenoceptors can be identified within the human prostate, contractile properties are mediated primarily by α 1 adrenoceptors. Many clinical investigations have confirmed that α 1 -adrenoceptor blockade relieves lower urinary tract symptoms (LUTS), both of irritative and obstructive type, in patients with BPH.
Lower urinary tract symptoms (LUTS) also develop in women as they age. As in men, LUTS in women includes both filling symptoms such as urgency, incontinence, and nocturia, and voiding symptoms, such as weak stream, hesitancy, intermittency, incomplete bladder emptying and abdominal straining. That both men and women experience a similar high prevalence of filling and voiding LUTS suggests that at least part of the underlying etiology may be identical. In a recent study, an α 1 -antagonist was reported to reduce LUTS in women to a greater extent than an anticholinergic (Serels, S. and Stein, M., Neurology and Urodynamics 17: 31-36, 1998). The authors concluded that there appeared to be a role for α 1 -antagonists in treating LUTS in women. The possible mechanisms implicated to explain these results are: a) dysfunction of the bladder neck and urethra, causing functional outlet obstruction, analogous to BPH-induced outlet obstruction, with secondary detrusor overactivity; and b) increased α 1 -adrenoreceptor activity in the detrusor, causing frequency and urgency. On these bases, α 1 -antagonists are used in clinical practice to treat LUTS in women. (Fitzpatrick, International British J. Urol . 85, Supp. 2: 1-5 (2000); Kakizaki, M. et al., Brit. J. Urol International 85, Supp. 2: 25-30 (2000)). The results of Serels also indicate that the combined administration of α 1 -antagonists and anticholinergics can have improved efficacy in treatment of LUTS, as suggested by Fitzpatrick ( International British J. Urol . 85, Supp. 2: 1-5 (2000)). The results of Serels also indicate that the combined administration of α 1 -antagonists and anticholinergics can have improved efficacy in treatment of LUTS, as suggested by Fitzpatrick, International British J. Urol . 85, Supp. 2: 1-5, 2000).
Another possible use of α 1 -antagonists is the management of neurogenic lower urinary tract dysfunction (NLUTD), as can be caused by neurological disease or trauma. NLUTD may lead to debilitating symptoms and serious complications, including increased urinary frequency, incontinence, voiding difficulty, recurrent upper urinary tract infections, and upper urinary tract deterioration. Management of NLUTD is indicated to preserve renal function and avoid urological complications. Administration of α 1 -antagonists may benefit patients with NLUTD by facilitating urine storage by alleviating high detrusor pressure during bladder filling, which is evidenced by poor bladder compliance and detrusor hyperreflexia. In both animal models and patients with spinal cord injury resistant to anticholinergics, α 1 -antagonists improved bladder compliance. (Kakizaki, M. et al., Brit. J. Urol International 85, Supp. 2: 25-30, 2000; Sundin, T. et al., Invest. Urol . 14: 322-328, 1977; McGuire et al., Neurology and Urodynamics 4: 139-142 ,1985; Swrerzewski, S. J. et al., J. Urol . 151: 951-954, 1994).
Two distinct α 1- adrenoceptor subtypes have been suggested to be present in the human prostate, one with high (α 1H ) and one with low (α 1L ) affinity for prazosin. All three high-affinity α 1 adrenoceptor subtypes found in molecular cloning studies have been identified in prostatic stromal tissue. The α 1a subtype was found to be the dominant, representing about 60-85% of the α 1- adrenoceptor population. Recent findings suggest that there may be differences in subtype populations between normal and hyperplastic prostates, the ratios between the subtypes α 1a :α 1b :α 1d being 85:1:14 in BPH and 63:6:31 in non-BPH tissue.
The α 1A- adrenoceptor was reported to mediate the contractile response of the human prostate in vitro. Ford et al. found that the α 1A adrenoceptor may not mediate contractile responses to noradrenaline, and suggested as a candidate the α 1L adrenoceptor. Findings by Kenny et al. (Br. J. Pharmacol., 118:871-878, 1996) support the view that the α 1L adrenoceptor, which appears to share many of the characteristics of an α 1A adrenoceptor, mediates the contractile response of the human prostate.
On the other hand, it has also been suggested that the α 1A and α 1L adrenoceptors may represent distinct pharmacological forms of the same receptor.
In the female urethra, mRNA for the α 1 subtype was predominant and autoradiography confirmed the predominance of the α 1A adrenoceptor (Andersson, K. E., Brit. J. Urol. Intl . 85, Supp. 2: 12-18, 2000). The α 1A and α 1D subtypes are reported to be present in the human detrusor, with the latter subtype predominant (Malloy, B. et al., J. Urol 160: 937-943, 1998). Accordingly, the evidence that α 1 adrenoreceptor antagonists are useful in treating lower urinary tract symptoms of both prostatic and non-prostatic origin in both males and females can be used to support the usefulness of the compounds of the present invention in treating such symptoms regardless of whether they are of obstructive origin or not and regardless of the sex of the patient.
The affinity of the compounds of the invention for each receptor can be assessed by receptor binding assays, for example as follows:
(1) α 1 -adrenergic-receptor subtypes: using the specific ligand 3 H-prazosin, according to Testa et al., Pharmacol. Comm . 6: 79-86, 1995; Cotecchia, S., Schwinn, D. A., Randall, R. R. and Lefkowitz, F. J., Proc. Natl. Acad. Sci. USA , 85: 7159-7163 (1988); Furchgott. R. E., Handbook of Experimental Pharmacology—New Series , 283-335 (1972); Michel, M. C., Hanft, G. and Gross, G., Brit. J. Pharmacol . 111: 533-538 (1994); Schwinn, D. A., Lomasney, J. W., Lorenz, W., Szklut, P. J., Fremcau, R. T., Yang-Feng, T. L., Caron, M. G., Lefkowitz, R. J. and Cotecchia, S., J. Biol. Chem . 265: 8183-8189 (1990); Testa, R., Guarneri, L., Ibba, M., Strada, G., Poggesi, E., Taddei, C., Simonazzi, I. and Leonardi, A. Europ. J. Pharmacol . 249: 307-315 (1993).
(2) 5HT 1A -serotonergic receptor: using the specific ligand 3 H-8-OH-DPAT according to Fargin et al., Nature 335: 358-360, (1988); Kobilka, B. K. et al., Nature 329: 75-79 (1987); Cullen, B. R., Meth. Enzym . 152: 684-704 (1987); Gozlan, H. et al., J. Receptor Res . 7: 195-221 (1987).
The α 1L -adrenergic receptor is not yet cloned and, therefore, the functional affinity of the compounds of the invention for this subtype can be assessed by using an isolated organ preparation as reported by Testa et al., J. Pharmacol. Exp. Ther . 281: 1284-1293, (1997); Oshita, M., Kigoshi, S. and Muramatsu, I., Br. J. Pharmacol . 108: 1071-1076 (1993).
In vitro testing of the compounds of this invention on the above receptors is described in Examples 8 and 9 below.
The drugs having α 1 -adrenergic antagonistic activity currently used for the symptomatic therapy of BPH are poorly subtype selective and subject to cause relevant side effects due to their hypotensive activity.
Thus there is a need for selective α 1 -antagonists which do not subject the BPH patient to the side effects, especially the cardiovascular side effects of said treatment.
The high uroselectivity of the compounds of the invention has been demonstrated by the dog model of the Example 10 below, where their efficacy in counteracting the contractions of prostatic urethra at doses that do not influence blood pressure has been shown.
SYNTHESIS OF THE COMPOUNDS OF THE INVENTION
The compounds according to the invention may be generally prepared as follows:
Direct condensation of 7-oxo-7H-thieno[3,2-b]pyran-3-carboxylic acids of the formula I with the ω-aminoalkylamino derivatives 2 (SCHEME 1) leads to the compounds of the invention. The condensation can be carried out in the presence of a condensing agent (e.g., dicyclohexylcarbodiimide or diethyl cyanophosphonate) optionally in the presence of a promoting agent (e.g., N-hydroxysuccinimide, 4-dimethylaminopyridine or N,N′-carbonyldiimidazole) in an aprotic or chlorinated solvent (e.g., N,N-dimethylformamide or chloroform) at −10/140° C. (Albertson, Org. React., 12:205-218, 1962; Doherty et al., J. Med. Chem., 35:2-14, 1992; Ishihara, Chem. Pharm. Bull., 39:3236-3243, 1991). In some cases the activated ester or amide intermediates (such as O-(N-succinimidyl) esters or acyl imidazolides) can be isolated and further reacted with 2 to be transformed into the corresponding amides (I) in an aprotic or chlorinated solvent at 10/100° C. This kind of condensation is well illustrated in the
Examples. Another activated intermediate which can be used is the mixed anhydride of 1, obtainable reacting 1 with an alkyl chloroformate in the presence of a tertiary amine (e.g., triethylamine or N-methylmorpholine), which is reacted with 2 at 0-80° C.; optionally a promoting agent (e.g., 1-hydroxypiperidine) may be added before the amine addition (Albertson, Org. React., 12:157, 1962).
Alternatively the condensation can be carried out without a solvent at 150-220° C. (Mitchell et al., J. Am. Chem. Soc., 53; 1879, 1931) or in high-boiling ethereal solvents (e.g., diglyme).
The condensation can also be performed through preparation and optional isolation of reactive derivatives of 1 such as acyl halides. Formation of acyl halides of compounds of formula 1 and reactions with amines 2 to form amides is well documented in the literature and known to people skilled in the art.
Also less reactive derivatives of 1 can be used, such as alkyl esters, which in turn can be converted into I in the presence of a condensing agent (e.g., trimethylaluminum) in an aprotic and/or chlorinated solvent (e.g., hexane, dichloromethane) at −10/80° C., or without solvents at 80-180° C., (Weinreb et al., Tetrahedron Lett., 4171, 1977; Lipton et al., Org. Synth., 59:49, 1979).
By the same methods of condensation reported above and using H 2 NCH 2 (CH 2 ) n CH 2 X (with X=halogen or OH) as a reagent, 1 can be transformed into 3. In the case of X=OH, the alcoholic group is then converted into a suitable leaving group by methods well known to those skilled in the art. Compounds 3 (with X=leaving group such as halogen or alky/arylsulphonyloxy group) can be subsequently reacted with an appropriate phenylpiperazine 8 bearing the desired phenyl group. The nucleophilic substitution is carried out preferably, but not necessarily, at a temperature within the range of 20-200° C. in a polar solvent such as dimethylformamide, acetonitrile, methanol, or without any solvent, usually in the presence of a base such as potassium carbonate. See also Gibson's chapter in Patai: “The Chemistry of the Amino Group”, p. 45 et seq., Wiley International Science, N.Y., 1968.
The preparation of compounds 2 which are not commercially available is disclosed in the literature and is well known to those skilled in the art, and is usually carried out performing nucleophilic substitution of a phenylpiperazine 8 on a N-(ω-haloalkyl)phthalimide or a proper ω-haloalkylnitrile or haloalkylamide by the method illustrated above for the condensation of compounds 3 and 8, or by addition of an α,β-unsaturated alkylnitrile or alkylamide in a proper solvent (e.g., acetonitrile, dimethylformamide, a chlorinated solvent or other aprotic polar solvent) at a temperature between 0° C. and the reflux temperature of the solvent. Standard phthalimido-group deprotection or reduction of the amido or cyano group then provides compounds 2, and can be performed by methods well known to those skilled in the art.
The acids 1 of the invention in which R represents cycloalkyl or aryl group can be synthesized (SCHEME 2) starting from methyl 2-acetyl-3-hydroxythiophene-4-carboxylate (prepared as described in J. Chem. Soc. Perkin Trans I, 507, 1986), which can be esterified with the proper alkanoyl or aroyl chloride by using methods very well known to those skilled in the art. Alternative procedures include the same methods described above for the amidification of 1, which could be applied as well in the esterification step to afford 4.
Monobromination of the methylketo group of 4 can afford 5, which can then be reacted with triphenylphosphine (typically by reflux in acetonitrile, toluene, or other aprotic solvent), to give the phosphonium salt 6. A subsequent intramolecular ester-Wittig reaction applied to this substrate yields the thieno[3,2-b]pyranes, 7. Hydrolysis of the ester group of compounds 7 is accomplished by acid or base catalysed procedures that are well known to those skilled in the art, yielding compounds 1.
Such hydrolysis procedures include the use of sodium hydroxide in aqueous ethanol at 40-75° C., or lithium hydroxide in aqueous dimethylformamide, or tetrahydrofuran at 40-100° C.
The compounds 1 where R is a polyfluoroalkyl group can be prepared from 2-acetyl-3-hydroxythiophene-4-carboxylate following the cyclization procedure described by Riva et al., (Synthesis, 195-201, 1997) by direct cyclization in the presence of anhydrous polyfluoroalkanoyl anhydrides catalysed by 1,8-diazabicycloundec-7-ene.
The compounds I where R 1 is a trifluoromethanesulphonyloxy group can be synthesized starting from compounds I where R 1 is a hydroxy group using procedures well known to those skilled in the art, by way of example without limitation, using trifluoromethanesulphonic anhydride or N-phenyltrifluoromethanesulphonimide in aprotic solvents such as 1,2-dichloroethane or other chlorinated solvents or toluene, at a temperature in the range between 20° C. and the temperature of reflux of the solvent (Hendickson et al., Tetrahedron Letters, 4607-4510, 1973). The N-oxides of the compounds I may be synthesized by simple oxidation procedures known to those skilled in the art. The oxidation procedure described in P. Brougham in Synthesis, 1015-1017 (1987) allows differentiation of the two nitrogen atoms of the piperazine ring and both the N-oxides and N,N′-dioxides to be obtained.
Preparation of the phenylpiperazines 8, which has not been described in the literature, is well documented in the examples and uses synthetic procedures well known to those skilled in the art, which comprise the synthesis of the proper aniline through standard reactions and the subsequent cyclization with bis-(2-chloroethyl)amine to afford the piperazine following the method of Prelog (Collect. Czech.Chem.Comm., 5:497-502, 1933) or its variations (Elworthy, J. Med. Chem., 40:2674-2687, 1997).
DETAILED SYNTHESIS OF THE COMPOUNDS OF THE INVENTION
Below are some examples intended only to illustrate the invention so as described in the test, with no intention to limit it.
EXAMPLE 1
N-{3-[4-(5-Chloro-2-methoxyphenyl)-1-piperazinyl]propyl}-7-oxo-5-phenyl-7H-thieno [3,2-b]pyran-3-carboxamide
a) 1-(5-Chloro-2-methoxyphenyl)-4-[3-(N-phthalimido)propyl]piperazine (Compound 1A)
A mixture of of 28.64 g of 1-(5-chloro-2-methoxyphenyl)piperazine, 44.6 g of anhydrous potassium carbonate and 33.65 g of N-(3-bromopropyl)phthalimide in 250 mL of acetonitrile was stirred at reflux for 8 hours. After cooling to 20-25° C., 800 mL of water was added under stirring and the resulting suspension was filtered by suction yielding a yellowish solid, which was washed with 300 mL of water and crystallised from methanol affording 46.5 g of the title compound, melting at 131-133° C.
1 H-NMR (200 MHz) spectrum Solvent CDCl 3 , Chemical shift (δ)
7.78-7.82
m
2 H
phthalimide H3, H6
7.64-7.78
m
2 H
phthalimide H4, H5
6.92
dd
1 H
methoxyphenyl H4
6.65-6.78
m
2 H
methoxyphenyl H3, H6
3.81
s
3 H
CH 3 O
3.71-3.89
m
2 H
CH 2 N(CO) 2
2.78-3.00
m
4 H
3 and 5 piperazine CH 2 s
2.40-2.65
m
6 H
2 and 6 piperazine CH 2 s, CH 2 CH 2 CH 2 N(CO) 2
1.80-2.03
m
2 H
CH 2 CH 2 CH 2
b) 1-(3-Aminopropyl)-4-(5-chloro-2-methoxyphenyl)piperazine trihydrochloride.2.15 H 2 O (Compound 1B)
A solution of 20.7 g of Compound 1A and 8.6 mL of 85% hydrazine hydrate in 300 mL of ethanol were stirred at reflux for 3.5 hours. Afterwards, the reaction mixture was cooled to 20-25° C., diluted with 400 mL of water, acidified with 37% hydrochloric acid (pH=1and stirred for 0.5 hour. The precipitated solid was collected by filtration and washed with 1N hydrochloric acid followed by water. The filtrate was concentrated by evaporation in vacuo, filtered, made basic by addition of 35% sodium hydroxide at 0-5° C. and extracted with diethyl ether. The organic layer was washed with brine, dried on sodium sulphate and evaporated to dryness in vacuo affording 13.6 g (96%) of the title compound as a base. Acidification of the solution of the base in chloroform with more than three equivalents of 3N ethanolic hydrogen chloride followed by evaporation to dryness in vacuo and crystallization of the residue from ethanol/diethyl-ether 10:3 yielded the title compound, melting at 200-202° C.
1 H-NMR (200 MHz) spectrum Solvent DMSOd 6 , Chemical shift (δ)
11.20-11.50
br
1 H
NH +
8.10-8.40
br
3 H
NH3 +
6.85-7.10
m
3 H
phenyl H3, H4, and H6
5.10
br
5.3 H
NH + , 2.15 H 2 O
3.79
s
3 H
CH 3 O
3.35-3.65
m
4 H
2 piperazine CH2s
3.03-3.35
m
6 H
2 piperazine CH2s, CH 2 CH 2 CH 2 NH 3 −
2.80-3.03
m
2 H
CH 2 CH 2 CH 2 NH 3 +
1.95-2.22
m
2 H
CH 2 CH 2 CH 2 NH 3 +
c) Methyl 2-acetyl-3-benzoyloxythiophene-4-carboxylate (Compound 1C)
3.48 mL of benzoyl chloride was added dropwise to a solution of 5.0 g of methyl 2-acetyl-3-hydroxythiophene-4-carboxylate (prepared as described in J. Chem. Soc. Perkin Trans I, 1986, 507) and 3.66 g of 4-dimethylaminopyridine in 100 mL of dichloromethane at 20-25° C. and stirred for 2 hours. The mixture was washed with 0.5N hydrochloric acid, water (2×20 mL), 2.5% aqueous sodium bicarbonate (2×40 mL) and water (2×20 mL). The organic layer was dried with sodium sulphate, evaporated to dryness in vacuo and purified by flash chromatography using chloroform/ethyl-acetate (100:1). The yield of Compound 1C was 7.089, as a yellow deliquescent solid, which was used in the next step without further purification.
1 H-NMR (200 MHz) spectrum Solvent CDCl 3 , Chemical shift (δ)
8.36
s
1 H
thiophene H5
8.20-8.42
m
2 H
phenyl H2, H6
7.52-7.78
m
3 H
phenyl H3, H4, H5
3.73
s
3 H
CH 3 O
2.50
s
3 H
CH 3 CO
d) Methyl 2-(2-bromoacetyl)-3-benzoyloxythiophene-4-carboxylate (Compound 1D)
A solution of 1.28 mL of bromine in 24 mL of tetrachloromethane was added dropwise to a solution of 7.23 g of Compound 1C in 72 mL of tetrachloromethane over a period of 10 minutes and stirred at reflux. After a further 5 minutes at reflux, the mixture was cooled to 20-25° C. The precipitated solid was collected by filtration and washed with cold tetrachloromethane to yield 7 g (77%) of Compound 1D, melting at 115-118° C. The compound was contaminated with impurities 1B and methyl 2-(2,2-dibromoacetyl)-3-benzoyloxythiophene-4-carboxylate (2% and 6% mol. respectively, determined by 1 H-NMR spectroscopy), but could be used without further purification in the next reaction step.
1 H-NMR (200 MHz) spectrum Solvent CDCl 3 , Chemical shift (δ)
8.43
s
1
H
thiophene H5
8.20-8.42
m
2
H
phenyl H2, H6
7.52-7.80
m
3
H
phenyl H3, H4, H5
6.70
s
0.06
H
CHBr 2
4.30
s
1.84
H
CH 2 Br
3.73
s
3
H
CH 3 O
2.50
s
0.06
H
CH 3 CO
e) 2-[(3-Benzoyloxy-4-methoxycarbonl)-2-thienyl]-2-oxoethyltriphenylphosphonium bromide hemihydrate (Compound 1E)
A solution of 6.9 g of compound 1D and 5.19 g of triphenylphosphine in 45 mL of acetonitrile was stirred at reflux for 4 hours and then cooled to 20-25° C. The precipitate was collected by filtration to yield 10.27 g (88%) of Compound 1E, melting at 150-152° C., which was pure enough to be used in further reactions. 0.27 g of crude product was crystallized from i-PrOH to yield 0.24 g of the analytical sample. M.p. (124)128-132° C.
1 H-NMR (200 MHz) spectrum Solvent CDCl 3 , Chemical shift (δ)
8.38-8.50
m
3 H
PhCO H2, H6 and thienyl H5
7.41-7.87
m
18 h
(C 6 H 5 )3P and PhCO H3, H4, H5
6.35
d
2 H
CH 2 P
3.71
s
3 H
CH 3 O
f) Methyl 7-oxo-5-phenyl-7H-thieno[3,2-b]pyran-3-carboxylate (Compound 1F)
150 mL of 1M aqueous sodium carbonate was added to a solution of 10.07 g of Compound 1E in 200 mL of 1,2-dichloroethane and the mixture was stirred at 85° C. for 11 hours, then cooled. The organic layer was separated, washed with water to neutrality, dried over anhydrous sodium sulphate and evaporated to dryness in vacuo to yield 8.67 g of a crude residue. The crude residue was purified by flash chromatography with petroleum ether/ethyl acetate 6:4 to yield 4.1 g (92%) of Compound 1F, melting at 169-171° C. Compound 1F was crystallized from methanol to give the analytical sample. M.p. 169-171° C.
8.50
s
1 H
H2
7.95-8.05
m
2 H
phenyl H2, 6
7.50-7.60
m
3 H
phenyl H3, 4, 5
6.88
s
1 H
H6
4.00
s
3 H
CH 3 O
g) 7-Oxo-5-phenyl-7H-thieno[3,2-b]pyran-3-carboxylic acid (Compound 1G)
26 mL of 0.6N sodium hydroxide was added to a solution of 3.82 g of Compound 1F in 174 mL of methanol and 87 mL of dioxane at 50° C. while stirring. The mixture was stirred at 50° C. for an additional 20 minutes, cooled to 20-25° C., then diluted with 280 mL of water, filtered and acidified with 1N hydrochloric acid to pH=1. The suspension of that formed precipitate gel was stirred at 60° C. for 2 hours, until a heavier filtrable solid was obtained. This solid was filtered and dried to yield 3.4 g of the title compound, which was suitable for use in the next reaction step without further purification. It was crystallized from ethanol to yield the analytical sample, melting at 282-283° C.
1 H-NMR (200 MHz) spectrum Solvent CDCl 3 , Chemical shift (δ)
13.39
bs
1 H
COOH
8.50
s
1 H
H2
8.00-8.05
m
2 H
phenyl H2, H6
7.52-7.60
m
3 H
phenyl H3, H4, H5
7.13
s
1 H
H6
h) N-{3-[4-(5-Chloro-2-methoxyphenyl)-1-piperazinyl}-propyl]-7-oxo-5-phenyl-7H-thieno[3,2-b]pyran-3-carboxamide
0.54 mL of 93% diethyl cyanophosphonate and 0.46 mL of triethylamine were added to a solution of 0.82 g of Compound 1G and 0.94 g of Compound 1B base in 15 mL of anhydrous N,N-dimethylformamide at 0° C. while stirring. The mixture was stirred for 22 hours at 20-25° C., poured into 150 mL of water. The solution was decanted and the pasty precipitate that remained was dissolved in 60 mL of chloroform, washed with water, dried over sodium sulphate, and evaporated to dryness in vacuo.
The crude materials was purified by flash chromatography with ethyl acetate/methanol (9:1) and evaporated to yield the pure title compound (1.2 g; 74%), which was crystallized from EtOAc. M.p. 165-166.5° C.
1 H-NMR (200 MHz) spectrum Solvent CDCl 3 , Chemical shift (δ)
8.45
s
1 H
H2
7.90-8.02
m
2 H
phenyl H2, H6
7.55-7.62
m
3 H
phenyl H3, H4, H5
7.45
t
1 H
CONH
6.95
dd
1 H
chlorophenyl H4
6.83
s
1 H
H6
6.65-6.75
m
2 H
chlorophenyl H3, H6
3.81
s
3 H
CH 3 O
3.66
dt
2 H
CONHCH 2
2.74-2.92
m
4 H
2 piperazine CH 2 s
2.48-2.54
m
6 H
CH 2 N and 2 piperazine CH 2 s
1.80-2.00
m
2 H
CH 2 CH 2 CH 2
EXAMPLE 2
N-{3-[4-(2-Methoxyphenyl)-1-piperazinyl]propyl}-7-oxo-5-phenyl-7H-thieno[3,2-b]pyran-3-carboxamide
The title compound was prepared as described in Example 1h, but substituting 1-(3-aminopropyl)-4-(2-methoxyphenyl)piperazine (prepared as described in patent GB 2,161,807) for Compound 1B. After pouring the reaction mixture into water and extracting with ethyl acetate, the combined organic layers were washed with water (3×80 mL), dried over sodium sulphate and evaporated to dryness in vacuo. The crude product was purified by flash chromatography with ethyl acetate/methanol (8.5:1.5) and evaporated to dryness. The residue yielded the pure title compound (1.4 g; 77%), which was crystallized from EtOAc to yield the title compound melting at 161-162° C.
1 H-NMR (200 MHz) spectrum Solvent CDCl 3 , Chemical shift (δ)
8.41
s
1 H
H2
7.90-8.02
m
2 H
phenyl H2, H6
7.50-7.65
m
4 H
NHCO and phenyl H3, H4, H5
6.80
s
1 H
H6
6.70-7.05
m
4 H
Chs of methoxyphenyl ring
3.83
s
3 H
CH 3 O
3.66
dt
2 H
CONHCH 2
2.80-3.00
m
4 H
2 piperazine CH 2 s
2.48-2.62
m
6 H
CH 2 N adn 2 piperazine CH 2 s
1.80-2.00
m
2 H
CH2CH 2 CH 2
EXAMPLE 3
5-Cyclohexyl-N-{3-[4-(2-methoxyphenyl)-1-piperazinyl]propyl}-7-oxo-7H-thieno[3,2-b]pyran-3-carboxamide
a) Methyl 2-acetyl-3-cyclohexanecarbonyloxythiophene-4-carboxylate (Compound 3A)
This compound was prepared as described for compound 1C of Example 1, but using cyclohexanecarbonyl chloride instead of benzoyl chloride. The crude product was purified by flash chromatography using a petroleum ether/ethyl acetate gradient from 9:1 to 7:3 to afford Compound 3A (80%).
1 H-NMR (200 MHz) spectrum Solvent CDCl 3 , Chemical shift (δ)
8.30
s
1 H
thiophene H5
3.80
s
3 H
CH 3 O
2.50
s
3 H
CH 3 CO
1.00-3.00
m
11 H
cyclohexane CHs
b) Methyl 2-(2-bromoacetyl)-3-cyclohexanecarbonyloxythiophene-4-carboxylate (Compound 3B)
A solution of 0.70 mL of bromine in 3.45 mL of acetic acid was added dropwise over a period of 60 minutes to a solution of 3.56 g of Compound 3A in 34.5 mL of acetic acid at 20-25° C. while stirring. After stirring further for 2.5 hours at 20-25° C., the mixture was poured into ice water and extracted with diethyl ether (2×80 mL). The combined organic layers were washed with water (2×80 mL), 10% aqueous sodium carbonate (100 mL) and water (3×80 mL), dried over sodium sulphate and evaporated to dryness in vacuo. The crude product was purified by flash chromatography in n-hexane/chloroform (6:4) to yield 1.31 g (29%) of Compound 3B.
1 H-NMR (200 MHz) spectrum Solvent CDCl 3 , Chemical shift (δ)
8.36
s
1 H
thiophene H5
4.29
s
2 H
CH 2 Br
3.83
s
3 H
CH 3 O
2.65-2.80
m
1 H
cyclohexane CH
2.15-2.25
m
2 H
2, 6 cyclohexane CHs (eq.)
1.85-1.95
m
2 H
2, 6 cyclohexane CHs (ax.)
1.25-1.80
m
6 H
3, 4, 5 cyclohexane CH 2 s
c) 2-[(3-Cyclohexanecarbonyloxy-4-methoxycarbonyl)-2-thienyl]-2-oxoethyltriphenylphosphonium bromide (Compound 3C)
A solution of 0.20 g of compound 3B and 0.13 g of triphenylphosphine in 1.25 mL of acetonitrile was stirred at reflux for 2.5 hours and then cooled to 0-5° C. The precipitate was collected by filtration, then washed on the filter with a 2:1 mixture of ethyl-acetate/acetonitrile, followed by ethyl acetate, to yield 0.19 g (59%) of Compound 3C melting at 165-167° C.
1 H-NMR (200 MNz) spectrum Solvent CDCl 3 , Chemical shift (δ)
8.31
s
1 H
thiophene H5
7.55-8.00
m
15 H
(C 6 H 5 ) 3 P
6.35
d
2 H
CH 2 P
3.79
s
3 H
CH 3 O
2.60-2.75
m
1 H
cyclohexane CH
1.95-2.05
m
2 H
2, 6 cyclohexane CHs (eq.)
1.10-1.70
m
8 H
other cyclohexane CHs
d) Methyl 5-cyclohexyl-7-oxo-7H-thieno[3,2-b]pyran-3-carboxylate (Compound 3D)
A mixture of 0.16 g of Compound 3C, 2 mL of 1,2-dichloroethane and 2 mL of 1M aqueous sodium carbonate was heated at 45° C. for 36 hours. After cooling to 20-25° C., 5 mL of chloroform was added, the organic layer was washed with water (2×10 mL), dried on anhydrous sodium sulphate and evaporated to dryness in vacuo. The crude product was purified by flash chromatography (petroleum ether/ethyl acetate 1:1) yielding 0.05 g (68%) of Compound 3D as a white solid, melting at 114-119° C.
1 H-NMR (200 MHz) spectrum Solvent CDCl 3 , Chemical shift (δ)
8.43
s
1 H
H2
6.20
s
1 H
H6
3.94
s
3 H
COOCH 3
2.55-2.70
m
1 H
cycloexane CH
1.15-2.15
m
10 H
cycloexane CH 2 s
e) 5-Cyclohexyl-7-oxo-5-phenyl-7H-thieno[3,2-b]pyran-3-carboxylic acid (Compound 3E)
0.3 mL of 1N sodium hydroxide and 1.0 mL of water were added to a solution of 0.040 g of Compound 3D in 1.8 mL of MeOH and 0.9 mL of 1,4-dioxane at 20-25° C., while stirring. The mixture was heated at 50° C. for 3.5 hours. After cooling to 20-25° C., the mixture was diluted with water and acidified to pH 1 with 3N hydrochloric acid. The precipitated solid was collected by filtration and washed with water to afford 0.028 g (73.5%) of the title compound, melting at 269-275° C.
1 H-NMR (200 MHz) spectrum Solvent DMSO-d 6 , Chemical shift (δ)
13.30
bs
1 H
COOH
8.78
s
1 H
H2
6.23
s
1 H
H6
2.55-2.70
m
1 H
cycloexane CH
1.10-2.05
m
10 H
cycloexane CH 2 s
f) 5-Cyclohexyl-N-{3-[4-(2-methoxyphenyl)-1-piperazinyl]propyl}-7-oxo-7H-thieno[3,2-b]pyran-3-carboxamide
The title compound was prepared as described in Example 2, but substituting Compound 3E for Compound 1G. The crude product was purified by flash chromatography in ethyl acetate:2.7N methanolic ammonia (95:5). The residue, obtained after solvent evaporation from the collected fractions containing the pure title compound (0.03 g; 73%) was dissolved in 5 mL of MeOH and the opalescent solution was clarified with charcoal. Solvent evaporation yielded the pure title compound as a yellow pasty solid (67%).
1 H-NMR (200 MHz) spectrum Solvent CDCl 3 , Chemical shift (δ)
8.41
s
1 H
H2
7.15
5
1 H
NH
6.85-7.10
m
4 H
methoxyphenyl Chs
6.21
s
1 H
H6
3.86
s
3 H
OCH 3
3.60
q
2 H
NHCH 2
3.00-3.15
m
4 H
2 piperazine CH 2 s
2.55-2.80
m
7 H
2 piperazine CH 2 s, cyclohexane CH and
CH 2 CH 2 CH 2
2.05
dt
2 H
CH 2 CH 2 CH 2
1.20-1.95
m
10 H
cyclohexane CH 2 s
EXAMPLE 4
N-{3-[4-(2-Methoxyphenyl)-1-piperazinyl]propyl}-7-oxo-5-trifluoromethyl-7H-thieno[3,2-b]pyran-3-carboxamide
a) Methyl 7-oxo-5-trifluoromethyl-7H-thieno[3,2-b]pyran-3-carboxylate (Compound 4A)
3.95 mL of trifluoroacetic anhydride and 9.2 mL of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) were added to a mixture of 4.10 g of methyl 2-acetyl-3-hydroxythiophene-4-carboxylate and 14 mL of pyridine at 0-5° C. The mixture was heated at 80° C. for 27 hours, during which time a total of 9.9 mL of trifluoroacetic anhydride and a total of 9.2 ml and DBU were added in three additions. The mixture was cooled to 20-25° C., poured into a mixture of ice (250 g) and 37% hydrochloric acid (50 mL), and extracted with ethyl acetate (2×80 mL). The combined organic layers were washed with water, dried over sodium sulphate and evaporated to dryness in vacuo. The residue was taken up with petroleum-ether/ethyl-acetate (7:3) and filtered. The filtrate was purified by flash chromatography using a petroleum ether/ethyl acetate gradient (7:3 to 0:1). The residue was dissolved in diethyl ether, washed with 5% aqueous sodium carbonate and water, dried over sodium sulphate and evaporated to dryness in vacuo to yield the title product (22%) melting at 148-158° C., which could be used in the next step without further purification. The analytical sample was obtained by crystallisation from ethanol. M.p. 163-164° C.
1 H-NMR (200 MHz) spectrum Solvent: CDCl 3 , Chemical shift (δ)
8.58
s
1 H
H2
6.80
s
1 H
H6
3.96
s
3 H
COOCH 3
b) 7-Oxo-5-trifluoromethyl-7H-thieno[3,2-b]pyran-3-carboxylic acid (Compound 4B)
A mixture of 0.70 g of Compound 4A, 5.6 mL of dioxane and 8.4 mL of 9N hydrochloric acid was stirred at reflux for 75 minutes. After cooling to 20-25° C., the precipitated solid was filtered, washed with dioxane/water 1:1.5 and water to afford 0.46 g of the title compound as a grey solid melting at 249-251° C.
1 H-NMR (200 MHz) spectrum Solvent: DMSO-d 6 , Chemical shift (δ)
13.50
bs
1 H
COOH
8.25
s
1 H
H2
7.19
s
1 H
H6
c) N-{3-[4-(2-Methoxyphenyl)-1-piperazinyl]propyl}-7-oxo-5-trifluoromethyl-7H-thieno[3,2-b]pyran-3-carboxamide
The title compound was prepared as described in Example 2 substituting Compound 4B for Compound 1G. The crude product was purified by flash chromatography in ethyl acetate/2.7N ammonia in methanol (95:5) affording the title compound as a light-brown solid melting at 170-177° C. (33%).
1 H-NMR J(200 MHz) spectrum Solvent: CDCl 3 , Chemical shift (δ)
8.55
s
1 H
H2
7.10
t
1 H
NH
6.85-7.10
m
4 H
methoxyphenyl Chs
6.80
s
1 H
H6
3.88
s
3 H
OCH 3
3.60
l
2 H
NHCH 2
2.90-3.15
m
4 H
2 piperazine CH 2 s
2.45-2.80
m
6 H
2 piperazine CH 2 s, CH 2 CH 2 2CH 2 N
1.88
dt
2 H
CH 2 CH 2 CH 2
EXAMPLE 5
7-Oxo-5-phenyl-N-{3-[4-[2-(2,2,2-trifluoroethoxy)phenyl]-1-piperazinyl]propyl}-7H-thieno[3,2-b]pyran-3-carboxamide
a) N-(3-Chloropropyl)-7-oxo-5-phenyl-7H-thieno[3,2-b]pyran-3-carboxamide (Compound 5A)
This compound was prepared as described above, in Example 1, with the substitution of 3-chloropropylamine hydrochloride for Compound 1B and doubling the amount of triethylamine used. After dilution with water, the precipitated solid was filtered and, while still on the filter, washed with cold-water:dimethylformamide (2:1) and then with water. The washed solid was suspended in 10% aqueous sodium carbonate, stirred, filtered and washed with water to neutrality. Drying at 70° C. in vacuo yielded the title compound (95%).
1 H-NMR (200 MHz) spectrum Solvent: CDCl 3 , Chemical shift (δ)
8.52
s
1 H
H2
7.75-7.85
m
2 H
phenyl H2, H6
7.50-7.60
m
3 H
phenyl H3, H4, H5
7.00
s
1 H
NH
6.80
s
1 H
H6
3.65-3.80
m
4 H
CH 2 CH 2 CH 2
2.15
dt
2 H
CH 2 CH 2 CH 2
b) 7-Oxo-5-phenyl-N-{3-[4-[2-(2,2,2-trifluoroethoxy)phenyl]-1-piperazinyl]propyl}-7H-thieno[3,2-b]pyran-3-carboxamide
A mixture of 0.17 g of Compound 5A, 0.13 g of 1-[2-(2,2,2-trifluoroethoxy)phenyl]-piperazine (prepared as described by EP 0748 800, G. Bantle et al.) and 0.07 g of potassium carbonate was heated at 200° C. for 20 minutes. After cooling to 20-25° C., the crude residue was purified by flash chromatography in ethyl acetate/methanol gradient (95:5 to 9:1) to yield 0.193 g (70%) of the title compound. M.p. 152-158° C.
1 H-NMR (200 MHz) spectrum Solvent: CDCl 3 , Chemical shift (δ)
8.45
s
1 H
H2
7.80-7.95
m
2 H
phenyl H2, Hy
7.50-7.65
m
4 H
CONH, phenyl H3, H4, H5
6.80
s
1 H
H6
6.75-7.10
m
4 H
tribluoroethoxyphenyl CHs
4.44
q
2 H
CH 2 O
3.66
dt
2 H
CONHCH 2
2.90-3.05
m
4 H
2 piperazine CH 2 s
2.50-2.70
m
6 H
CH 2 N and piperazine CH 2 s
1.80-2.00
m
2 H
CH 2 CH 2 CH 2
EXAMPLE 6
N-{3-[4-[2-Methoxy-5-(2,2,2-trifluoroethoxy)phenyl]-1-piperazinyl]propyl}-7-oxo-5-phenyl-7H-thieno[3,2-b]pyran-3-carboxamide
a) 1-t-Butoxycarbonyl-4-(5-hydroxy-2-methoxyphenyl)piperazine (Compound 6A)
A solution of 8 g of 1-(5-hydroxy-2-methoxyphenyl)piperazine dihydrobromide and 3.17 g of anhydrous potassium carbonate in 30 mL of water was evaporated to dryness in vacuo. 100 mL of anhydrous tetrahydrofuran and 5.18 g of 97% di-t-butyl dicarbonate (BOC 2 O) were added to the residue and the mixture was stirred at 20-25° C. for 2 hours, followed by addition of 100 mL of anhydrous tetrahydrofuran. The suspension was filtered and the filtrate evaporated to dryness in vacuo. The residue was dissolved in 200 mL of chloroform. The solution was washed with 5% sodium bicarbonate (3×50 ml) and water (2×50 mL), and dried over sodium sulphate. The solvent was removed at reduced pressure and the residue was purified by flash chromatography in petroleum ether/ethyl acetate (75:25) to yield 1.91 g (28.7%) of Compound 6A and 1.58 g (35.7%) of 1-t-butoxycarbonyl-4-(5-t-butoxycarbonyloxy-2-methoxyphenyl)piperazine. A solution of this by-product in 40 mL of methanol and 6 mL of 1N sodium hydroxide was maintained overnight at 20-25° C. The mixture was neutralized with acetic acid, solvent was removed at reduced pressure and the remaining residue was dissolved in 40 mL of chloroform. After washing with water (3×10 mL) the organic layer was dried over sodium sulphate and the solvent evaporated in vacuo to recover an additional 1.15 g (17.2%) of Compound 6A as a thick oil (total yield 45.9%).
1 H-NMR (200 MHz) spectrum Solvent: CDCl 3 , Chemical shift (δ)
6.70
d
1 H
H3 of phenyl ring
6.45-6.53
m
2 H
H4 and H6 of phenyl ring
5.77
s
1 H
OH
3.78
s
3 H
CH 3 O
3.48-3.68
m
4 H
2 piperazine CH 2 s
2.82-3.05
m
4 H
2 piperazine CH 2 s
1.48
2
9 H
(CH 3 ) 3 C
b) 1-t-Butoxycarbonyl-4-[2-methoxy-5-(2,2,2-trifluoroethoxy)phenyl]piperazine (Compound 6B)
A mixture of 2.83 g of Compound 6A, 6.05 g of cesium carbonate and 2.95 g of 2,2,2-trifluoroethyl p-toluenesulphonate in 60 mL of acetonitrile was refluxed for 16 hours while stirring. The solvent was evaporated off at reduced pressure, 90 mL of brine was added to the residue, and the mixture was extracted with ethyl acetate (3×40 mL). The organic layer was washed with water (3×20 mL) and of brine (20 mL) and dried over sodium sulphate. The solvent was removed at reduced pressure and the residue purified by flash chromatography in a petroleum ether/ethyl acetate gradient (95:5 to 80:20). The solvents were removed in vacuo to yield 1.86 g (52%) of Compound 6B as a white solid. M.p. (98) 102-105° C.
1 H-NMR (200 MHz) spectrum Solvent: CDCl 3 , Chemical shift (δ)
6.77
d
1 H
H3 of phenyl ring
6.45-6.63
m
2 H
H4 and H6 of phenyl ring
4.28
q
2 H
CF 3 CH 2 O
3.84
s
3 H
CH 3 O
3.53-3.68
m
4 H
2 piperazine CH 2 s
2.90-3.06
m
4 H
2 piperazine CH 2 s
1.48
s
9 H
(CH 3 ) 3 C
c) 1-[2-Methoxy-5-(2,2,2-trifluoroethoxy)phenyl]piperazine. 1.9 hydrochloride (Compound of 6C)
A solution of 2.42 mL of trifluoroacetic acid in 30 mL of anhydrous dichloromethane was added dropwise to a solution of 1.17 g of Compound 6B in 40 mL of anhydrous dichloromethane at 3-5° C. while stirring. The mixture was maintained overnight at 20-25° C., washed with 2N sodium hydroxide (2×30 mL) and extracted with 2N hydrochloric acid (3×15 mL). The aqueous acid layer was washed with diethyl ether (2×20 mL) brought to an alkaline pH with 37% sodium hydroxide at 5-10° C., and extracted with diethyl ether (3×30 mL). The organic layer was dried over sodium sulphate and the solvent was removed in vacuo to yield 0.78 g (89%) of compound 6C base as a thick oil. A solution of the compound 6C base in diethyl ether was treated with coal, filtered and acidified by addition of 3.6N HCl in diethyl ether to yield the hydrochloride salt, which was recovered by filtration and crystallized from acetonitrile and ethanol to yield the analytical sample. M.p. (188) 202-208° C. (dec.)
1H-NMR (200 MHz) spectrum Solvent: DMSO-d 6 , Chemical shift (δ)
9.18
bs
2.9 H
NH 2 + and NH +
6.90
d
1 H
phenyl H3
6.67
dd
1 H
phenyl H4
6.59
d
1 H
phenyl H6
4.66
q
2 H
CF 3 CH 2 O
3.74
s
3 H
CH 3 O
3.18
bs
8 H
piperazine CH 2 s
d) N-{3-[4-[2-Methoxy-5-(2,2,2-trifluoroethoxy)phenyl]-1-piperazinyl]propyl}-7-oxo-5-phenyl-7H-thieno[3,2-b]pyran-3-carboxamide
This compound was prepared as described above, in Example 5b, with the exception that Compound 6C was used in place of 1-[2-(2,2,2-trifluoroethoxy)phenyl]piperazine. After cooling to 20-25° C., the crude residue was purified by flash chromatography in ethyl acetate:2N ammonia in methanol (98:2) to yield the title compound (60%). M.p. 156-158° C.
1 H-NMR (200 MHz) spectrum Solvent: CDCl 3 , Chemical shift (δ)
8.50
s
1 H
H2
7.80-7.95
m
2 H
phenyl H2, H6
7.40-7.80
m
4 H
CONH, phenyl H3, H4, H5
6.85
s
1 H
H6
6.75
d
1 H
trifluoroethoxyphenyl H3
6.40-6.55
m
2 H
trifluoroethoxyphenyl H4, H6
4.30
q
2 H
CH 2 O
3.80
s
3 H
CH 3 O
3.65
dt
2 H
CONHCH 2
2.50-3.10
m
10 H
piperazine CH 2 s and CH 2 N
1.85-2.10
m
2 H
CH 2 CH 2 CH 2
EXAMPLE 7
N-{3-[4-[4-Fluoro-2-(2,2,2-trifluoroethoxy)phenyl]-1-piperazinyl]propyl}-7-oxo-5-phenyl-7H-thieno[3,2-b]pyran-3-carboxamide
This compound was prepared as described in Example 5b, with the exception that 1-[4-fluoro-2-(2,2,2-trifluoroethoxy)phenyl]piperazine (prepared as described by G. Bantle et al. in EP 748 800, 1966) was used in place of 1-[2-(2,2,2-trifluoroethoxy)-phenyl]piperazine. After cooling to 20-25° C., the crude residue was purified by flash chromatography in ethyl acetate/2N ammonia in methanol (95:5) to yield the title compound (74%). M.p. 189-191° C.
1 H-NMR (200 MHz) spectrum Solvent: CDCl 3 , Chemical shift (δ)
8.45
s
1 H
H2
7.80-7.95
m
2 H
Phenyl H2, H6
7.45-7.65
m
4 H
CONH, phenyl H3, H4, H5
6.80
s
1 H
H6
6.65-6.75
m
2 H
trifluoroethoxyphenyl CHs
6.60
dd
1 H
trifluoroethoxyphenyl CH
4.35
q
2 H
CH 2 O
3.65
dt
2 H
CONHCH 2
2.80-3.00
m
4 H
2 piperazine CH 2 s
2.50-2.70
m
6 H
CH 2 N and 2 piperazine CH 2 s
1.90-2.00
m
2 H
CH 2 CH 2 CH 2
EXAMPLE 8
Determination of Affinity for Cloned α 1 Adrenergic Receptors and 5-HT 1A Serotoninergic Receptors by Radioligand Binding Assay
Determination of affinity for cloned subtypes of the α 1 -adrenoceptor was performed in membranes from cells transfected by electroporation with DNA expressing the genes encoding each α 1 -adrenoceptor subtype.
Cloning and stable expression of the α 1 -adrenoceptor gene were performed as previously described (Testa et al., Pharmacol. Comm., 6:79-86, 1995 and references). The cell membranes were incubated in 50 nM Tris, pH 7.4, with 0.2 nM [ 3 H]prazosin, in a final volume of 1.02 mL for 30 minutes at 25° C., in the absence or presence of competing drugs (1 pM-10 μM). Non-specific binding was determined in the presence of 10 μM phentolamine. Incubation was stopped by addition of ice-cold Tris buffer and rapid filtration through Schleicher & Schuell GF52 filters that had been pretreated with 0.2%-polyethyleneimine.
Genomic clone G-21 coding for the human 5-HT 1A -serotoninergic receptor was stably transfected in a human cell line (HeLa) (Fargin et al., J. Biol. Chem., 284:14848-14852, 1989). HeLa cells were grown as monolayers in Dulbecco's modified Eagle's medium (DMEM), supplemented with 10% fetal calf serum and gentamicin (100 μg/mL), at 37° C. in 5% CO 2 . The cells were detached from the growth flask at 95% confluence by a cell scraper and were lysed in a buffer containing ice cold 5 mM Tris, 5 mM EDTA, (pH 7.4). The homogenates were centrifuged at 40,000×g for 20 minutes and the membranes were resuspended in a small volume of ice-cold buffer containing 5 mM Tris and 5 mM, EDTA (pH 7.4), and immediately frozen and stored at −70° C. until use.
On the day of experiment, the cell membranes were resuspended in a buffer containing 50 mM Tris (pH 7.4), 2.5 mM MgCl 2 , 10 μM pargyline (Fargin et al., Nature, 335:358-360, 1988). The membranes were incubated in a final volume of 1 mL for 30 minutes at 30° C. with 1.2 nM [ 3 H]8-OH-DPAT, in the absence or presence of test molecules. Non-specific binding was determined in the presence of 10 μM 5-HT. Incubation was stopped by addition of ice-cold Tris buffer and rapid filtration through Schleicher & Schuell GF52 filters that had been pretreated with 0.2%-polyethyleneimine.
Inhibition of specific binding of the radioligands by the test drugs was analyzed to estimate the IC 50 value by using the non-linear curve-fitting program Allfit (De Lean et al., Am. J. Physiol., 235:E97-E102, 1978).
The IC 50 value was converted to an affinity constant (Ki) by the equation of Cheng et al., (Biochem. Pharmacol., 22:3099-3108, 1973). Data were expressed as mean of Ki.
RESULTS
The compounds of the invention exhibited the desired potency and selectivity at α 1 adrenoceptors, as shown in Table 1.
TABLE 1
Affinity (Ki, nM) of the different compounds tested for recombinant α 1 -
adrenoceptor subtypes and 5-HT 1A receptor.
Human cloned receptors
Example
α 1a
α 1b
α 1d
5-HT 1A
1
0.58
2.53
4.12
2
0.10
7.52
2.46
4.48
4
0.60
23.16
3.60
26.21
5
0.045
4.34
1.01
7.59
6
3.19
39.31
48.17
1081.00
7
0.17
3.47
2.45
88.54
Compound A
0.60
3.29
2.84
4.53
Prazosin
0.61
0.42
0.23
>100000
EXAMPLE 9
In vitro Evaluation of Functional Antagonism for α IL Adrenoceptors
The functional α 1 -antagonistic activity of the test compounds against noradrenaline(NA)-induced contractions of rabbit aorta pretreated with chloroethylclonidine (α 1L receptor) was evaluated according to the method of Testa et al., (J. Pharmacol. Exp. Ther., 281:1284-1293, 1997). Adult male New Zealand rabbits were sacrificed by cervical dislocation. The aorta was removed, placed in Krebs-Henseleit buffer and dissected free of adhering tissue. Rings were prepared from each artery (8 rings per aorta, about 4-5 mm wide) and suspended in 20 mL organ bath containing Krebs bicarbonate buffer of the following composition: 112 mM NaCl, 5.0 mM KCl, 2.5 mM CaCl 2 , 1.0 mM KH 2 PO 4 , 1.2 mM MgSO 4 , 12.0 mM NaHCO 3 and 11.1 mM glucose, equilibrated at 37° C. with 95% O 2 : 5% CO 2 . Desmethylimipramine (0.1 μM) and corticosterone (1 μM) to block neuronal and extraneuronal uptake of NA, (±)-propranol (1 μM) to block β adrenoceptors and yohimbine (0.1 μM) to block α 2 adrenoceptors were added to the buffer. The tissues were subjected to a passive load of 2 g and the tension developed was measured using isometric transducers (Basile 7003).
The preparations were equilibrated for 60 minutes and then primed every 30 minutes with 10 μM NA for three times. The aortic rings were then incubated with the alkylating agent chloroethylclonidine (50 μM) for 30 minutes and then washed extensively three times, over a 30 min period before constructing the NA-concentration/response curve. Following washing, tissue was re-equilibrated for 45 min. Test drug was added and after 30 minutes, a second cumulative-NA-concentration/response curve was constructed. Each antagonist concentration was tested using 2-3 aortic rings from different rabbits.
Dose ratios (i.e., the ratio between the concentrations of noradrenaline required to produce half-maximal response in the presence and in the absence of the test antagonist) were calculated at each concentration of the compounds. The logarithm of these dose ratio −1 was plotted against the logarithm of the compound concentrations (Schild plot) to evaluate the affinity constant Kb.
When only one or two concentrations of the test compounds were utilised, the apparent Kb value was calculated using the formula: Kb=[B]/(DOSE RATIO−1), where B is the antagonist concentration.
RESULTS
The compounds tested showed good affinity for the α 1L adrenoceptor subtype. The data are expressed as pKb in Table 2.
TABLE 2
Functional affinity of the tested compounds for the α 1L adrenoceptor
subtype.
Example
pKb
1
8.17
2
8.85
4
7.92
5
9.12
7
8.66
Comp A
8.64
Prazosin
8.11
EXAMPLE 10
Effects on Urethral Contractions Induced by Noradrenaline Injection and Blood Pressure in Dogs after Intravenous Administration
The experiments were performed according to the method of Imagawa et al (J. Pharmacol. Methods, 22:103-111, 1989), with substantial modifications, as follows: adult male beagle dogs, weighing 8-10 kg, were anaesthetized with pentobarbital sodium (30 mg/kg i.v. and 2 mg/kg/h i.v.), intubated and spontaneously ventilated with room air. In order to monitor systemic blood pressure (BP), a polyethylene (PE) catheter was introduced into the aortic arch through the left femoral artery. A collateral of the left femoral vein was cannulated for infusion of anaesthetic, and the right femoral vein was cannulated for administration of compounds. For intraarterial (i.a.) injection of noradrenaline (NA), a PE catheter was introduced into the lower portion of the abdominal aorta via the right external iliac artery. Through such procedure, NA was selectively distributed to the lower urinary tract. A paramedian vertical suprapubic incision extending from the base of the pelvis to the mid-abdominal region was made and the bladder and the prostate were exposed. The bladder was manually emptied with a syringe. Prostatic urethral pressure was monitored with a Mikro-tip catheter (5F) introduced into the bladder via the external urethral meatus, and withdrawn until the pressure transducer was positioned in the prostatic region of the urethra. A ligature was secured between the neck of the bladder and urethra to isolate the response of the latter and to avoid any interaction with the bladder. Another ligature was put around the Mikro-tip catheter at the external meatus, to secure the catheter itself.
After a stabilizing period following the surgical procedure (30 minutes), in which arterial and prostatic urethral pressures were continuously monitored as basal values, i.a. administration of NA was made at intervals of 20 minutes.
The NA doses were chosen to produce an increase of at least 100% in urethral pressure. The test compounds were administered intravenously in a cumulative manner with intervals of 15-20 minutes between administrations. I.a. injections of NA were repeated 5 minutes after every dosing of test compound with intervals of about 10 minutes between stimulations. In order to compare the effects of the administered compound, dose/response curves (log dose transformation) were constructed by computing, at the peak effect, the percent decrease in diastolic blood pressure and percent inhibition of the increase in urethral pressure induced by NA. Linear regression equations were then used in order to evaluate the theoretical effectiveness as ED 25 (the effective dose inducing a 25% decrease in diastolic blood pressure) and ID 50 (the dose inhibiting by 50% the increase in urethral pressure).
RESULTS
The effects obtained after intravenous administration of the compounds of examples 1, 2 and 5 are shown in Table 3. Results obtained after injection of prazosin and Comp A are also shown in the table.
TABLE 3
Data represent the active doses (expressed in μg/kg) inhibiting
by 50% the urethral contractions (UC) induced by noradrenaline (NA),
the active doses (expressed in μg/kg) in lowering diastolic blood
pressure (DBP) and the ratio (DBP/US) between the active doses.
Compound
UC ID 50 NA
DBP ED 25
Ratio
1
5.3
280
52.8
2
1.8
35.5
19.7
5
2.7
>1000
>370
Prazosin*
3.6
6.6
1.83
Comp A*
2.4
243
101.2
*Data from Leonardi et al., J. Pharmacol. Exp. Ther. 281:1272-1283, 1997.
The pharmacological results confirm that the compounds of the invention are α 1- adrenoceptor antagonists with good selectivity for the α 1 adrenoceptor compared to the 5-HT 1A receptor, and good affinity also for the α 1L subtype, as far as in vitro data are concerned.
The in vivo pharmacological results confirm the high uroselectivity of the compounds of the invention and justify their possible use in the treatment of obstructive diseases of the lower urinary tract, including BPH.
Effective Amounts
The following represent guidelines to effective oral, parenteral or intravenous dose ranges for human hosts, expressed in mg/kg of body weight per day, for use in obstructive disorders of the lower urinary tract:
General
0.001-20
Preferred
0.05-3
Most preferred
0.5-2
The most-preferred values refer to oral dosing. Intravenous dosages should be 10 to 100 fold lower. Selective-use dosages, i.e., dosages that are active in the lower urinary tract without a substantial effect on blood pressure, depend on the particular compound employed. Generally, in the case of a compound selective in inhibiting urethral contraction, up to four times the amount of the ED 50 used in inhibiting urethral contraction can be administered without substantial effect on blood pressure. Further refinements and optimization of dosages are possible using simple routine experiments. The active compounds of the invention may be orally administered, for example, with an inert diluent or with an edible carrier, or they may be enclosed in gelatine capsules, or they may be compressed into tablets. For the purpose of oral therapeutic administration, the active compounds of the invention may be incorporated with excipients and used in the form of tablets, troches, capsules, elixirs, suspensions, syrups, wafers, chewing gum and the like. These preparations should contain at least 0.5% of active compounds, but the amount of active ingredient may be varied depending upon the particular form and may conveniently be between 5% and about 70% of the weight of the unit. The amount of active compound in such compositions is such that a suitable dosage will be obtained although the desired dosage can be obtained by administering a plurality of dosage forms. The preferred compositions and preparations according to the invention are prepared so that an oral dosage unit form contains between 1.0-300 milligrams of active compound. The tablets, pills, capsules, troches and the like may also contain, for example, the following ingredients: a binder such as microcrystalline cellulose, gum tragacanth or gelatine; an excipient such as starch or lactose; a disintegrating agent such as alginic acid, sodium starch glycolate, cornstarch and the like; a lubricant such as magnesium stearate or hydrogenated castor oil, a glidant such as colloidal silicon dioxide; a sweetening agent such as sucrose or saccharin; and a flavoring agent such as peppermint, methyl salicylate, or orange flavoring. When the dosage unit form is a capsule, it may contain, in addition to materials of the above type, a liquid carrier such as a fatty oil. Other dosage unit forms may contain other various materials which modify the physical form of the dosage unit, for example as coatings. Thus, tablets or pills may be coated with sugar, shellac, or other enteric coating agents. A syrup may contain, in addition to the active compounds, sucrose as a sweetening agent and certain preservatives, dyes, coloring and flavors. The materials used in preparing these various compositions should be pharmaceutically pure and nontoxic in the amounts used. For the purpose of parenteral therapeutic administration, the active compounds of the invention may be incorporated into a solution or suspension. These preparations should contain at least 0.1% of active compound, but it may be varied between 0.5 and about 30% of the weight thereof. The amount of active compound in such compositions is such that a suitable dosage will be obtained. The preferred compositions and preparations according to the present inventions are prepared so that a parenteral dosage unit contains between 0.2 to 100 milligrams of active compound. The solutions or suspensions may also include the following components: a sterile diluent such as water for injection, saline solution, fixed oils, polyethylene glycols, glycerine, propylene glycol or other synthetic solvents; antibacterial agents such as benzyl alcohol or methyl parabens; antioxidants such as ascorbic acid or sodium bisulfite; chelating agents such as ethylenediaminetetraacetic acid; buffers such as acetates; citrates or phosphates and agents for the adjustment of tonicity such as sodium chloride or dextrose. The frequency of administration of the present compounds and compositions may be adjusted based on need and physician's advice but will typically be once or twice a day. The parenteral multiple-dose vials may be of glass or plastics material.
Additional compositions suitable for administration by various routes and containing compounds according to the present invention are also within the scope of the invention. Dosage forms, additional ingredients and routes of administration contemplated herein include those disclosed in the United States patents U.S. Pat. No. 4,089,969 to Muchowsk et al. and U.S. Pat. No. 5,091,182 to Ong et al., both incorporated by reference in their entirety. | The invention is directed to compounds of Formula I:
wherein
R is an aryl, cycloalkyl or polyhaloalkyl group,
R 1 is chosen from the group consisting of alkyl, alkoxy, polyfluoroalkoxy, hydroxy and trifluoromethanesulfonyloxy; each of R 2 and R 3 independently is chosen from the group consisting of a hydrogen, halogen, alkoxy and polyfluoroalkoxy group, and n is 0, 1 or 2.
The invention further provides pharmaceutical compositions comprising a compound of Formula I or a N-oxide or pharmaceutically acceptable salt of such a compound in admixture with a pharmaceutically acceptable diluent or carrier.
In another aspect, the present invention is directed to methods for selectively preventing contractions of the urethra and lower urinary tract, without substantially affecting blood pressure, by administering one or more selected compounds of Formula I to a mammal (including a human) in need of such treatment in an amount or amounts effective for the particular use.
In yet another aspect, the invention is directed to methods for blocking α 1 receptors, by delivering to the environment of said receptors, e.g., to the extracellular medium, (or by administering to a mammal possessing said receptors) an effective amount of a compound of the invention, in this way relieving diseases associated to overactivity of said receptors.
It is also an object of the present invention to provide a method of treating BPH which avoids any undue side effects due to acute hypotension (i.e., limited effects on blood pressure).
It is another object of the present invention to provide pharmaceutical compositions comprising 7-oxo-7H-thieno[3,2-b]pyran compounds which are selective α 1 adrenoceptor antagonists, which compositions are effective for the treatment of BPH optionally including a carrier or diluent.
It is another object of the present invention to provide a method of treating BPH using 7-oxo-7H-thieno[3,2-b]pyran compounds which are selective α 1 adrenoceptor antagonists.
Other aspects of the invention are the use of new compounds for lowering intraocular pressure, the treatment of cardiac arrhythmia and erectile dysfunction, treatment of sympathetically mediated pain, treatment of NLUTD, and treatment of LUTS in males and females.
In another aspect of the invention, compounds of the invention are administered in combination with anticholinergic compounds. | 2 |
FIELD OF THE INVENTION
[0001] This invention relates to the field of automatic transmissions for motor vehicles. More particularly, the invention pertains to transmissions which provide a continuous range of speed ratios, including zero, between the output speed and the input speed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0002] FIG. 1 is a schematic diagram of a transmission according to the present invention.
[0003] FIG. 2 is a table showing the proposed tooth numbers for the gears and sprockets of the transmission illustrated in FIG. 1 .
[0004] FIG. 3 is a table showing the speeds of various elements in various operating conditions when the gears and sprockets have the tooth numbers shown in FIG. 2 .
[0005] FIG. 4 is a table showing the state of the clutches for each operating mode.
DETAILED DESCRIPTION OF THE INVENTION
[0006] A transmission according to the present invention is illustrated schematically in FIG. 1 . Input shaft 10 is driven by the vehicle engine, preferably via a torsional isolator that smoothes out torque fluctuations due to discrete cylinder firings. Output shaft 12 drives the vehicle wheels, preferably via a differential.
[0007] A dual cavity toroidal variator transfers power from variator input disk 26 to variator output disks 28 and 30 , which are both fixed to intermediate shaft 36 . The variator is capable of efficiently transferring power at any speed ratio within its ratio range. In the present embodiment, the ratio range of the variator includes 2.211:1 overdrive and 0.463:1 underdrive. Two sets of power rollers 32 and 34 transfer power between the input disk and the output disks. The output disks always rotate in the opposite direction of the input disk. The axes about which the power rollers rotate is tilted to control the speed ratio of the variator. In the condition shown in FIG. 1 , the radius of the interface between the power roller and the input disk is greater than the radius of the interface between the power rollers and the output disks, causing the output disks to rotate at a faster speed than the input disk. When the power roller axes are tilted in the opposite direction, the output disks rotate slower than the input disk.
[0008] Two varieties of toroidal variator are well known: full-toroidal and half-toroidal. In a full-toroidal variator, the cavity between an input disk and an output disk is shaped like a torus. In a half-toroidal, as illustrated in FIG. 1 , only the inner portion of the torus is used. The present invention is applicable with either variety of toroidal variator.
[0009] Power is transmitted from the input shaft to the variator input disk by means of at least one layshaft 16 . Layshaft 16 is driven by the input shaft through internal gear 18 which meshes with external gear 20 . Internal/external gear meshes are more efficient than external/external gear meshes. Internal gear 18 must have a relatively large diameter, but this is acceptable because it is located in the bell housing portion of transmission case 14 . Layshaft 16 drives variator input disk 26 through external gears 22 and 24 . A second layshaft 68 , with external gears 70 and 72 , causes the separating forces of the gear meshes driving the variator input disk to partially or completely counteract one another, reducing the side loads on the variator input disk and simplifying the necessary support bearings.
[0010] A front planetary gear set drives intermediate shaft 46 at a predetermined proportion of the input shaft speed. Sun gear 38 is fixed to input shaft 10 . Ring gear 40 is fixed to transmission case 14 . Planet carrier 42 is fixed to intermediate shaft 46 . A set of planet gears 44 is supported on planet carrier 42 and meshes with both sun gear 38 and ring gear 42 .
[0011] A rear planetary gear set combines the speeds of intermediate shaft 46 and intermediate shaft 36 . Sun gear 48 is fixed to intermediate shaft 36 . Planet carrier 52 is fixed to intermediate shaft 46 . A set of planet gears 54 is supported on planet carrier 52 and meshes with both sun gear 48 and ring gear 50 . The number of teeth on the various gears are selected such that ring gear 50 is stationary for some variator speed ratio within the variator's available ratio range. This variator speed ratio is called the geared neutral ratio. An example of suitable tooth numbers is provided in FIG. 2 . When the variator ratio is set to a more underdrive ratio than the geared neutral ratio, ring gear 50 rotates in the same direction as the input shaft. Conversely, when the variator ratio is set to a more overdrive ratio than the geared neutral ratio, ring gear 50 rotates in the opposite direction as the input shaft.
[0012] Clutch 56 releasably connects ring gear 50 to output shaft 12 . Clutch 56 completes a power path that is suitable for reverse motion and low speed forward motion. Substantially the same result would be obtained by placing clutch 56 is other locations within this power path. For example, ring gear 50 could be fixed to output shaft 12 with clutch 56 replacing one of the other fixed connections, such as between input shaft 10 and sun gear 38 , between transmission case 14 and ring gear 40 , between planet carrier 42 and planet carrier 52 , or between intermediate shaft 36 and sun gear 48 . These alternative arrangements would result in different relative speeds when clutch 56 is disengaged, but identical behavior when clutch 56 is engaged. Clutch 58 releasably connects intermediate shaft 36 to output shaft 12 . Clutch 58 is applied for moderate to high speed forward motion. The number of teeth on the various gears are selected such that ring gear 50 and intermediate shaft 36 rotate at the same speed at a variator ratio that is close to the maximum underdrive variator ratio.
[0013] Intermediate shaft 63 is constrained to rotate at a speed proportional to layshaft 16 and in the same direction. Chain 64 meshes with sprocket 60 , which is fixed to layshaft 16 , and with sprocket 62 , which is fixed to intermediate shaft 63 . Clutch 66 releasably connects intermediate shaft 63 to output 12 . These elements form a fixed ratio power path suitable for highway cruising because it bypasses the variator and therefore has better mechanical efficiency. The number of teeth on the various gears and sprockets are selected such that intermediate shaft 63 and intermediate shaft 36 rotate at the same speed at a variator ratio that is close to the maximum overdrive variator ratio.
[0014] Clutches 56 , 58 , and 66 are preferably hydraulically actuated friction clutches which transmit torque when hydraulic pressure is applied and permit relative motion with low drag torque when the hydraulic pressure is removed. However, since the speeds of the elements may be synchronized before engaging the oncoming clutch, other types of couplers, such as dog clutches or switchable one way clutches, may be substituted for some or all of these clutches.
[0015] The vehicle is prepared for launch in reverse by disengaging all clutches and setting the variator ratio slightly on the overdrive side of the geared neutral ratio such that ring gear 50 rotates slowly backwards. In response to driver demand, clutch 56 is gradually engaged, accelerating the vehicle in reverse. The launch is completed when the speed of the output shaft reaches the same speed as ring gear 50 and clutch 56 is completely engaged. As the vehicle accelerates further, the variator ratio is adjusted to obtain a target engine speed selected based on driving conditions.
[0016] Similarly, the vehicle is prepared for launch in forward by disengaging all clutches and setting the variator ratio slightly on the underdrive side of the geared neutral ratio such that ring gear 50 rotates slowly forwards. In response to driver demand, clutch 56 is gradually engaged. The launch is completed when clutch 56 is completely engaged. As the vehicle accelerates further, the variator ratio is adjusted to obtain a target engine speed.
[0017] As the vehicle continues to accelerate, a point will be reached where the variator ratio is near its underdrive limit. At this point, the transmission is shifted from low mode to high mode by releasing clutch 56 while engaging clutch 58 . Unlike a gear change in a traditional step ratio transmission, this transition does not involve a change in the speed ratio between the output shaft and the input shaft. Once the transition to high mode is complete, the controller resumes adjusting variator ratio to obtain a target engine speed.
[0018] Typically, fixed ratio gearing provides better mechanical efficiency than power paths that include a variator. As a result, it may be preferable to shift to the fixed ratio mode when the vehicle is cruising at a moderately high speed. The transmission is shifted from high mode to fixed ratio mode by releasing clutch 58 while engaging clutch 66 . As shown in FIG. 3 , the tooth numbers shown in FIG. 2 result in a fixed ratio mode that is slightly more overdrive than the most overdrive ratio in high mode. As a result, this shift is an upshift with a very small ratio change. However, different speed ratios of the fixed ratio mode, either higher or lower, may be selected by adjusting the number of teeth on sprockets 60 and 62 without departing from the inventive concept.
[0019] A shift from fixed ratio mode back to high mode is accomplished by releasing clutch 66 while engaging clutch 58 . Preferably, the shift should be accomplished with the variator ratio set to minimize the overall ratio change. Similarly, a shift from high mode back to low mode is accomplished by releasing clutch 58 and engaging clutch 56 .
[0020] In accordance with the provisions of the patent statutes, the structure and operation of the preferred embodiment has been described. However, it should be noted that alternate embodiments can be practiced otherwise than as specifically illustrated and described. | An infinitely variable power transmission comprising an input shaft, a layshaft driven by the input shaft via internal/external gearing, a toroidal variator, and gearing and clutches which implement a low/reverse variable ratio mode and a high range variable ratio mode. An additional clutch and gearing implement an optional fixed ratio mode. | 5 |
This application is a continuation-in-part of application Ser. No. 08/606,219 filed Mar. 7, 1996, now U.S. Pat. No. 5,786,642 which is a continuation-in-part of application Ser. No. 08/328,574, filed Oct. 24, 1994, now U.S. Pat. No. 5,500,561 dated Mar. 19, 1996, which was a continuation of application Ser. No 08/129,375, filed Sep. 30, 1993, now U.S. Pat. No. 5,363,333, which is a continuation of application Ser. No. 07/944,796, filed Sep. 14, 1992, now abandoned, which is a continuation of application Ser. No. 07/638,637, filed Jan. 8, 1991 now abandoned.
BACKGROUND OF THE INVENTION
The field of the invention is high efficiency uninterruptable lighting systems.
Uninterruptable power supplies are well known accessories especially when applied to computer equipment to “ride out” brief power outages so that no data is lost or compromised. Some have more battery storage capability so that operation may be maintained for an extended outage. Some special lighting systems are also protected in a similar fashion by an uninterruptable power source for critical applications such as operating rooms in hospitals. In lieu of such systems, reduced amounts of auxiliary emergency lighting is provided for special areas by modular systems which are only engaged during power outages; these modules are often used in stairwells and consist of a housing enclosing a battery, charger, power sensor and one or two flood lamps.
These prior art systems do nothing to enhance lighting efficiency, and would not be considered as substitutes for conventional lighting.
OBJECTS OF THE INVENTION
It is an object of this invention to provide an uninterruptable lighting system that can be routinely substituted for conventional building or office lighting.
It is another object of this invention to provide high efficiency operation with lower operating cost than conventional incandescent and fluorescent lighting systems.
It is yet another object of this invention to provide long term uninterruptability (3 hours+) with small storage volumes.
It is an object of this invention to provide optimum battery management for long storage life, ultra low maintenance, and economical operation.
It is a further object of this invention to provide for economical connection to an alternate energy source such as a solar photovoltaic (PV) panel.
It is another object of this invention to provide a system with enhanced safety through low voltage operation between the power control unit and the lighting fixtures.
It is yet another object to achieve high power quality with low interference through very high power factor and low total harmonic distortion.
It is an object of this invention to provide for expansion of the lighting system through a modular approach to increase subsystem and component standardization to reduce cost.
SUMMARY OF THE INVENTION
In keeping with these objects and others, which may become apparent, the present invention includes a high efficiency lighting system for maintaining normal lighting conditions by lighting fixtures requiring DC electrical power.
The system includes a power control means for receiving AC electrical power from a grid source and delivering required low voltage DC electrical power to the lighting fixtures. The power control means converts the AC electrical power to DC electrical power.
A battery provides, on a standby basis, the required DC low voltage electrical power to the power control means. The battery is connected to the power control means so that the battery may be maintained in a fully charged condition by the power control means during normal supply of AC electrical power from the grid source.
The power control means delivers required DC electrical power from the battery to the lighting fixtures during an AC electrical power outage to maintain the power without interruption.
The power control means can be a plurality of multiple power control means, each connected to its own battery for maintaining the lighting in a building with multiple rooms.
An optional photovoltaic source of DC electrical power may be connected to the power control means for reducing the amount of electrical power taken from said grid source.
The battery provides, on a standby basis, DC low voltage electrical power to the power control means, which power control means maintains the battery in a fully charged condition by electrical power from an AC grid source.
In a version using AC power input only without an auxiliary battery or photovoltaic panel, the high efficiency lighting system for maintaining normal lighting conditions of lighting fixtures requiring DC electrical power, includes the power control means for receiving AC electrical power from a grid source and delivering required DC electrical power to the lighting fixtures, as well as a power control means converting AC electrical power to DC electrical power.
In a further embodiment for remote use, such as a remote campsite without access to conventional AC power, a high efficiency lighting system maintains normal lighting conditions of lighting fixtures requiring DC electrical power. The remote system includes a power control means for receiving DC electrical power from a photovoltaic panel and delivering required low voltage DC-electrical power to the remote lighting fixtures, and the power control means controls charging of a battery.
The battery also provides, on a standby basis, the required DC low voltage electrical power to the power control means. It is connected to the power control means while being maintained in a charged condition by the power control means, during daylight hours of input of power from the photovoltaic panel.
Moreover, the power control means delivers required DC electrical power from the battery to the lighting fixtures during periods of time when power from the photovoltaic panel is not available, such as at night times.
The present invention also provides A DC power supply system for DC loads requiring DC electrical power that includes power control means for receiving AC electrical power from a grid source and delivering required low voltage DC electrical power to said DC load. It converts the AC electrical power to DC electrical power.
In addition, one embodiment of the present invention includes a battery means that provides required DC low voltage electrical power on a standby basis to the power control means.
The battery means is connected to the power control means so as to permit the battery control means to maintain the battery in a fully charged condition during normal supply of AC electrical power from the AC grid source.
The power control means of the present invention delivers required DC electrical power from the battery means to a DC load during an AC electrical power outage so as to maintain normal operation of the DC load without interruption.
In addition, the present invention optionally provides a DC power supply system having a photovoltaic [PV] source of DC electrical power connected to the power control means in order to reduce the amount of electrical power taken from said grid source.
The DC power supply system of the present invention optionally further provides a cogeneration source of DC electrical power connected to the power control means to reduce the amount of electrical power taken from a grid source.
Further, the present invention alternatively provides a DC power supply for DC loads requiring DC electrical power. The DC power supply includes a separate power control means for receiving AC electrical power from a grid source. The DC power supply delivers required low voltage DC electrical power to a DC load. The power control means converts the AC electrical power to DC electrical power.
In addition, in an alternate embodiment, the DC power supply system for DC loads requiring DC electrical power includes a power control means for receiving DC electrical power from a DC power source and for delivering required low voltage DC electrical power to the DC load. The power control means is also directed toward the function of controlling charging of a battery means.
In this battery-charging embodiment, the present invention's battery means provides the required DC low voltage electrical power on a standby basis to the power control means.
Also, in this battery-charging embodiment, the battery means is connected to the power control means so as to maintain the power control means in a charged condition during hours of input from the DC power source.
Furthermore, in this battery-charging embodiment, the power control means delivers required DC electrical power from the battery means to the DC load during times when power from the DC power supply is not available.
The DC power supply system of the present invention further provides an optional embodiment wherein the DC power source is a cogeneration unit.
Alternatively, in a different embodiment of the present invention, the DC power supply system has a DC power source that is at least one photovoltaic panel.
In yet another embodiment of the present invention, the DC power supply system furnishes power to a DC load that is a household appliance. The household appliance may alternatively be a microwave oven, a heater, or any other household electrical device.
Furthermore, in further embodiments with or without access to conventional AC power, a DC generator (e.g.—powered by a natural gas engine) is used either as a primary source of electrical power or as a cogeneration companion to normal AC grid power. Thus the power control means can be supplied power for use by a high efficiency lighting system in much the same manner as DC electrical power is received from a photovoltaic panel.
It can be appreciated that any compatible DC load can be serviced by the power control means of this high efficiency lighting system in addition to DC ballasted fluorescent lighting or instead of the latter lighting load. These other DC loads can be supplied with standby power from a storage battery as well. Some examples of DC loads include household appliances, microwave ovens, and heaters.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention can best be understood in conjunction with the accompanying drawings, in which:
FIG. 1 is a block diagram of basic uninterruptable lighting system;
FIG. 2 is a physical block diagram of basic uninterruptable lighting system;
FIG. 3 is a wiring layout of a single lighting module;
FIG. 4 is a wiring layout of a four module system;
FIG. 5 is a block diagram of lighting system with a PV panel;
FIG. 6 is a front view of power control unit;
FIG. 7 is a wiring diagram and specs for two lamp ballast;
FIG. 8 is a wiring diagram and specs for single lamp ballast;
FIG. 9 is a front view of battery enclosure; and
FIG. 10 is a block diagram of power control unit.
FIG. 11 is a: block diagram of an alternate lighting system using natural gas cogeneration.
FIG. 12 is a block diagram of a customer side, power management system and illustrating its interface with existing electric utility power lines of the customer facility.
FIG. 13 is a schematic diagram of an alternate power management system.
FIG. 14 illustrates the invention with regard to incorporation of the linear voltage regulator and control interface as one means for controlling the charge level of the storage battery.
FIG. 15 illustrates the use of circuit breaker means and looping of a DC lighting circuit as well as auxiliary DC equipment and an inverter associated with a simplified illustration of the electric distribution box.
FIG. 16 illustrates a converter fed by a DC supply from a rectifier and providing an output to storage battery means illustrated as having a filter capacitor in electrical parallel therewith.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a block diagram of the major components of an uninterruptable lighting system of this invention. It may be installed anywhere conventional building lighting is required. Unlike emergency lighting, this is a full service, high quality lighting product. It functions with standard fixtures and lamps, without compromise in output quality and with no flicker in the event of a power failure. This permits normal building activities to continue for several hours using battery storage without disruption of work activity due to loss of lighting. The key subsystem that ties the entire system together is the power control unit 1 which normally uses AC grid power to supply the lighting energy and keep the battery 2 charged. The lighting fixtures 3 are fluorescent tubes using electronic ballasts which have a low voltage (nominal 26.6 volts) DC input supplied by line 5 from power control unit (PCU) 1 . During a power outage, the DC line 5 is supplied by battery 2 .
FIG. 2 shows a physical block diagram showing the AC electric service panel 6 with a three wire cable system supplying either 120 or 220 VAC to PCU 1 . Battery case 7 contains two group 24 / 27 deep discharge lead acid storage batteries wired in series and through a 30 amp fuse to the PCU 1 . The wiring to all lighting fixtures 3 is at a nominal 26.6 volts DC. In the preferred embodiment, each PCU can power ten two tube 48 inch T8 fluorescent fixtures or 20 single tube fixtures.
FIG. 3 shows a wiring layout for three offices as controlled by a single PCU 1 . A closet area 17 is used to house battery 2 . The AC line 4 leads to PCU I, which is placed in the ceiling cavity. The DC wiring 5 to the lighting fixtures is also in the ceiling cavity.
The 220 VAC input power to the PCU is 725 watts for an AC rms of approximately 3 amps. The equivalent 120 VAC unit will be about 6 amps. Because the PCU is power factor corrected to 0.99, a 20 amp circuit breaker and number 12 wire can support a maximum of 3 PCU's from a 120 volt line and 6 units from a 220 volt line for a total DC power output of about 2100 watts and 4200 watts respectively.
FIG. 4 shows a wiring layout serving 8 small offices and four larger ones. This involves the use of four separate uninterruptable lighting systems using four PCU's 1 and four battery modules 2 located in four central closets 17 . The four PCU's are supplied from a single 220 VAC circuit breaker in power panel 6 via AC cable 4 as distributed from distribution box 20 . Each of the lighting systems supplies 10 two lamp fixtures 3 .
FIG. 5 shows an uninterruptable lighting system including a PV panel 25 .
As shown in FIG. 6 , a front view of PCU 1 , it is simply wired to two terminals. This simple system configuration permits high security lighting using an AC line, battery back-up, and PV shared contribution. A system with the PCU alone attached to the AC line is a viable lighting system that can pay for itself by providing high efficiency DC lighting. By adding the battery subsystem, the user achieves uninterruptable lighting. By using a system without a battery but with AC input and a PV panel, the power savings of the PV contribution is achieved with the balance supplied by the AC input. In an area remote from the AC grid, a system using a PCU attached to a large PV panel and a larger battery can supply totally solar lighting. The PCU is sufficiently flexible to support all of these configurations of lighting systems. It can also supply other DC loads besides lighting, such as for example, household appliances, microwave ovens, heaters and the like. Furthermore, it can also alternately accept external DC power from many varied sources such as wind generators or engine powered generators.
FIG. 6 shows a front view of PCU 1 with finned heat sink 28 and terminal strip 29 .
FIGS. 7 and 8 show the wiring diagrams and specifications for the two lamp and one lamp DC ballasts respectively (designated as NB2756/2 and NB2727M respectively).
FIG. 9 shows a front view of the battery case with hinged lid 36 and latches 37 . It is a thermoplastic case rated only for sealed type lead acid batteries.
FIG. 10 shows a block diagram of the PCU 1 . The AC input is rectified by DC Rectifier Means 50 such as a bridge circuit. The Power Factor Correction Means 51 is used to achieve a high power factor (0.99) at the AC input. The Control Means 53 and Voltage Regulator means 52 interact through circuits such as pulse width modulation and DC to DC switching power supply topologies to provide the nominal 26.6 volts to the lighting ballasts or other suitable DC loads 57 through the power junction means 55 . Other voltages are also possible, such as 13.3, 26.6, 39.9 etc.
The Battery Undervoltage Cut-Off 56 disconnects the battery 2 in situations of depletion to prevent “over sulfation” or chemical and physical damage to the storage battery. The PV Voltage Regulator and Suppressor 54 is a power conditioner block to suppress voltage transients (such as from lightning strikes in the vicinity) and also to prevent over charging of the storage battery from the PV panel 25 .
An embodiment of control means 53 determines if the utility power drawn is above a manually pre-set threshold or a threshold derived from an automatic setpoint circuit. If the utility power drawn exceeds this threshold voltage regulator means 52 output voltage will be set such that power junction means 55 will be biased accordingly such that power to DC loads 57 will be drawn from storage battery 2 and/or PV source 25 through its PV voltage and suppressor 54 . In this manner. AC cower peaks from the utility are reduced as are monthly utility charges if a peak power surcharge is assigned. The power sharing-between PV source 25 and battery 2 is regulated by the output voltage of PV source 25 as modified by PV voltage regulator and suppressor 54 . The interaction of voltage output at suppressor 54 with that of battery 2 voltage via biasing within power function means 54 determines the level of power sharing between these DC secondary sources. The latter action also describes the sharing of power between PV panel 25 and battery 2 during periods of utility power outage.
FIG. 11 is an alternate embodiment for a loadside powered lighting system including natural gas in a cogeneration component. AC power 50 is normally converted to DC power by DC power converter 51 and control means 52 . However, a cogenerator in the form of a DC gas generator 53 receives natural gas from a natural gas source 54 , and sends DC power to building lighting system 55 , such as electronic ballasted fluorescent lighting. This system provides a flatter and more predictable power demand for electric utility customers at building lighting system 55 , since it supplants peak power from electric utility generating sources. This results in reduced demand charges, since gas offers a lower cost per unit of energy consumed, compared to conventional AC power from a public utility.
The cogeneration system can run continuously for lighting load 55 , without having to be sent back to AC line power 50 , which avoids the need for costly AC synchronization methods and sine wave purity, as is needed when sending excess-electricity back to a public utility.
DC gas generator 53 directly couples to building lighting system 55 through a diode isolator that allows either AC or DC power to operate building lighting system 55 .
Referring now to FIG. 12 of the drawings, it will be seen that a customer side, power management system formed in accordance with the present invention may be easily inter-connected with the existing electric power wiring of the customer facility to monitor the load requirements of the customer. To facilitate an understanding of the invention, FIG. 12 shows three phase power wiring (i.e., wires labeled L 1 , L 2 and L 3 representing each phase) and a neutral (i.e., N) wire coming from the utility and being received by the customer facility. The three phase wires, L 1 , L 2 and L 3 and the neutral wire N are received by a main distribution panel 202 of the customer facility. The main distribution panel 202 distributes the power throughout the facility, and in many cases provides power to a lighting distribution panel 204 , which, as its name implies, distributes power to the various lighting circuits of the facility. That is, the main distribution panel 202 conventionally distributes the three phase power wiring of the electrical utility throughout the consumer facility and in so doing distributes power to the various loads served by the customer facility. There are three types of very common AC electrical loads which may be required to be satisfied by the AC electrical power generated at the public or electrical facility and emanating from the illustrated consumer facility and they are a Lighting Load Semi-Random Punctuated Loads, and Semi-Random Longer Cycle Loads. Thus, the three phase power wiring L 1 , L 2 and L 3 and the neutral wiring N connects from the public utility side of the main distribution panel 202 and issues therefrom as AC electrical conductors on the customer side of this panel into connection with the composite of loads which are required to be satisfied by the power emanating from the electrical utility. Normally, the main distribution panel 202 and the lighting distribution panel 204 are interconnected by one or more power lines 206 , including a neutral line 208 , but for purposes of this invention, the interconnecting lines between the main distribution panel and the lighting distribution panel are interrupted, as illustrated by the broken lines in FIG. 12 . It will be understood that the interruptions of the lines between the main distribution panel 202 and the lighting distribution panel 204 with introduction of the inverter 110 are necessary only if the Lighting Load is not capable of being powered solely by direct current, as distinct from a situation where the Lighting Load may be powered in whole or in part, by AC power. To the extent it is not so capable, the inverter 110 must be employed to supply AC power, all in the event that there could be failure of the electrical facility to deliver any AC at all.
The power management system includes a power transducer 210 . The power transducer 210 has associated with it one or more voltage or current sensors 212 , each sensor being coupled to a respective power line phase. The power transducer 210 measures in real time the power consumed by the customer facility from the electric utility, and provides an output signal corresponding to this measurement. The output signal provided by the power transducer 210 is proportional in magnitude to the power consumed by the customer facility. For example, the output signal may be in terms of voltage, and have a range of from 1 to +10 or −10 volts, which would correspond to a power consumption of from 0 to 100 kilowatts. A suitable power transducer 210 , which may be used for the power management system of the present invention, is Part No. PCB-20 manufactured by Rochester Instrument Systems, Inc.
The output signal from the power transducer 210 is preferably provided to an integrator circuit 214 . The integrator circuit 214 averages the real time power measurement made by the power transducer. The integrator circuit 214 simulates the operation of a similar integration circuit, which the utility uses to average the peak power demands of its customers.
The integrator circuit 214 may be formed in various ways, including using an operational amplifier 216 with a feedback capacitor 218 and an input resistor 220 , as shown in FIG. 12 . The values of capacitor 218 and resistor 220 are selected to provide a desired integration time. The integrator circuit 214 shown in FIG. 12 provides a negative gain; accordingly, if such a circuit is used, it may be coupled to the 0 to −10 V output of the power transducer to provide a positive output voltage signal which varies in response to changes in power drawn from the utility and sensed by the sensor 212 .
The power management system further includes a comparator circuit, which in a preferred form is a differential amplifier circuit 220 . The output of the integrator circuit 214 is provided to a first input of the differential amplifier circuit 220 . A second input of the differential amplifier circuit 220 is connected to a switching circuit 222 , which is functionally depicted in FIG. 12 as a single pole, double throw switch 222 a.
More specifically, the “wiper” arm 224 of the switching circuit is connected to the second input of the differential amplifier circuit 220 , one pole 226 of the switching circuit is connected to an automatically adjustable set point circuit 228 , and the other pole 230 of the switching circuit is connected to a manually adjustable set point circuit 232 .
The automatically and manually adjustable set point circuits 228 , 232 provide at threshold signal, which may be in the form of a voltage, through the switching circuit 222 to the second input of the differential amplifier circuit 220 . The threshold signal represents the power level at which a secondary source of DC power, such as a storage battery 234 , forming part of the power management system is to take over in supplying power to one or more various loads in the customer's facility, as will be described.
Various manually adjustable set point circuits are envisioned to be used in the present invention. One example of such is a potentiometer 236 connected between positive and negative voltages or a voltage V 1 and ground, with its wiper arm connected to the pole 230 of the switching circuit 222 . Such a circuit would provide a threshold voltage to the differential amplifier circuit 220 . The set point circuit 232 would be adjusted after an analysis of the customer's energy consumption profile. The threshold would be set so that any stochastic or recurrent (i.e., non-random, time of day) peaks in the customer's daily power demand would be supplied in full or proportionally by the secondary DC power source of the power management system, as illustrated by FIG. 13 .
The automatically adjustable set point circuit 228 will periodically derive and store the maximum value of the actual peak power demands over predetermined time intervals, for example, daily or monthly, and provide a threshold which is based on a “moving average” computed by the circuit. This threshold signal is provided to the input of the differential amplifier circuit 220 through the switching circuit 222 . The automatic set point circuit 228 will automatically adjust the threshold signal in accordance with the moving average of the customer's peak power requirements, which it calculates algorithmically. An example of such a circuit is disclosed in U.S. Pat. No. 4,731,547, which issued to Phillip Alenduff et al., the disclosure of which is incorporated herein by reference.
As its name implies, the comparator (or more preferably the differential amplifier) circuit 220 will compare the threshold signal provided by either set point circuit 228 , 232 , which is selected by the switching circuit 222 with the output signal from the integrator circuit 214 , which output signal represents the power being drawn from the utility averaged over the predetermined integration period. IF the output signal from the integrator circuit 214 is greater in magnitude than the threshold signal, i.e., indicating that excessive or peak power is being consumed, the differential amplifier circuit 220 will sense this and provide a proportional output signal, which is compatible with that required to control an AC-to-DC converter or switching mode type power supply 238 forming part of the power management system, as will be described.
One form of a differential amplifier circuit 220 which is suitable for use in the present invention is an operational amplifier 240 having a feedback resistor 242 and an input resistor 244 , with the threshold signal being provided to the inverting input of the operational amplifier 240 through the input resistor 244 , and the output signal from the integrator circuit 214 being provided to one side of a second input resistor 243 whose other side is connected to the non-inverting input of the operational amplifier and to another resistor 245 to ground. When the values of the first input and feedback resistors 244 , 242 equal those of the second input and the ground resistors 243 , 245 respectively, the output signal from the differential amplifier circuit 220 will be a voltage level equal to the difference between the voltage levels of the integrator circuit's output signal and the threshold signal, multiplied by the ratio between the values of the feedback and first input resistors 242 , 244 . Accordingly, the output signal from the differential amplifier circuit 220 is preferably a voltage level which varies proportionally with the difference between the output signal from the integrator circuit 214 and the set point threshold signal level.
As will be described in greater detail, many AC-to-DC power supplies adjust their output voltage levels in proportionment to the voltage applied to their control signal input, and operate on positive control signal voltages, for example, 0 volts to 10 volts for an output adjustment of from 125 volts to 110 volts. To prevent negative voltage swings in the output signal from the differential amplifier circuit 220 , such as when the level of the output signal of the integrator circuit is below the set point threshold signal level, one can provide a positive supply voltage to the appropriate supply terminal of the operational amplifier 240 , and ground the negative supply terminal. Alternatively, one may connect a diode (not shown) having its anode connected to ground and its cathode connected to the output of the operational amplifier 240 to clamp the differential amplifier's output signal to 0 volts when the output signal from the integrator circuit 14 is less than the set point threshold signal level.
Instead of using the differential amplifier circuit 220 , which provides a continuously variable output signal which is proportional to the difference between the threshold signal and the integrator circuit's output signal, a simple comparator, such as in the form of an operational amplifier, may be used. The integrator's output signal and the threshold signal are provided to the two inputs of the comparator, and the comparator's output signal is provided to the control input of the AC-to-DC converter 238 . When the integrator circuit's output signal is greater than the threshold signal, the output signal of the comparator will be in a first state to signal the AC-to-DC converter 238 to provide a first output voltage level. When the integrator circuit's output signal is less than or equal to the threshold signal, the output signal of the comparator will be in a second state to signal the AC-to-DC converter 238 to provide a second output voltage level.
As mentioned previously, the power management system of the present invention includes an AC-to-DC converter circuit 238 . Preferably, the converter circuit 238 is a power supply of the switching type, which is known to have good regulation and high efficiency. The power line 206 and neutral line 208 from the main distribution panel 202 , which originally were provided to the lighting distribution panel 204 , are now provided to the AC inputs of the switching power supply 238 . The output signal from the comparator or differential amplifier circuit 220 is provided to the control input of the power supply. The switching power supply 238 will convert the AC power provided to it into a DC voltage and current to run a particular load or loads at the customer facility, such as a fluorescent lighting load 246 , as illustrated by FIG. 12. A suitable AC-to-DC switching power supply 238 which may be used in the power management system of the present invention is Part No. 2678644 manufactured by Technl Power Corp., a Penril Company, located in Connecticut. For greater power handling requirements, several power supplies may be connected in parallel, all being controlled by the comparator or differential amplifier circuit 220 . With whichever AC-to-DC converter 238 that is used, the comparator or differential amplifier circuit 220 is designed to provide the compatible control signal to vary the converter output as required.
The output voltage of the switching DC power supply 238 is adjustable proportionally to the control signal it receives. For example, the power supply 238 may be selected or designed such that control voltage provided to the control input of the power supply of from 0 to 10 volts will inversely adjust the output DC voltage of the power supply from 125 to 110 volts. As will be described in greater detail, the control of the output voltage of the AC-to-CD power supply 238 is an important aspect of the power management system, as it will allow the lighting or other load to be driven by power from the electric utility or from the secondary DC source, such as the storage battery 234 , situated at the customer facility.
The DC output voltage from the AC-to-DC power supply 238 is provided to a power isolation and distribution circuit 48 and to a second source of DC power, which, in the preferred form of the invention, is a storage battery 234 . More specifically, the positive terminal of the power supply 238 is provided to the input of the power isolation and distribution circuit 248 , one output of the power isolation and distribution circuit is provided to the power line 206 connected to the lighting distribution panel 204 , and another output of the power isolation and distribution circuit is provided to the positive terminal of the storage battery 234 . The negative output of the power supply 238 is provided to the negative output of the storage battery 234 and to the neutral line 208 connected to the lighting distribution panel 4 . Connected in this manner, the AC-to-DC power supply 238 will not only provide DC power to the lighting or other load 246 of the customer, but will also charge the storage battery at times of low power demand.
In a preferred form of the present invention, the power isolation and distribution circuit 248 basically consists of a series of three interconnected diodes 250 , 252 , 254 . The first diode 250 has its anode connected to the positive output terminal of the power supply 238 , and its cathode connected to the positive terminal of the storage battery 234 . The second diode 252 has its anode connected to the positive terminal of the storage battery 234 , and its cathode connected to the first output of the power isolation and distribution circuit 248 , which output is connected to the power line 206 provided to the lighting distribution panel 204 . The third diode 254 has its anode connected to the positive output terminal of the power supply 238 , and has its cathode connected to the cathode of the second diode 252 and to the first output of the power isolation and distribution circuit 248 .
The diodes of the power isolation and distribution circuit provide isolation between the storage battery 234 and the AC-to-DC power supply 238 , and provide a larger “dead band” or buffer region to allow the storage battery to be switched into the circuit, to supply power to the lighting of other load 246 , or isolated from the circuit. The diodes 250 - 254 used in the power isolation and distribution circuit are preferably high power, silicon diodes.
The power isolation and distribution circuit 248 , power supply 238 and storage battery 234 work in the following manner. Assuming the storage battery is 124 volts DC, and the output of the AC-to-DC power supply is 125 volts DC, for example, then the first and third diodes 250 , 254 are forward biased so that the potential at the first and second outputs of the power proportioning circuit is 124.3 volts each, assuming diode drops of 0.7 volts. The second diode 252 is essentially back biased and not turned on. The DC power supply 238 is supplying current to the lighting or other load 246 as well as to the storage battery 234 to charge the battery. This condition occurs during times when there is no peak power demand.
If, for example, the output of the AC-to-DC power supply decreases to 123 volts, then the first and third diodes 250 , 254 of the power isolation and distribution circuit are back biased, and the second diode 252 is forward biased. Under such conditions, the storage battery 234 contributes power to the lighting or other load. This condition occurs during peak power demands. The amount of power contributed by the battery 234 to the load is substantially equal to the amount of power drawn from the utility by the customer, which exceeds the set point threshold, up to the limit of the load.
For example, assume that the customer demand is 750 K watts, the set point threshold is set at 800 K watts, and the lighting load controlled by the power management system of the present invention is 100 K watts. Since the customer demand is below the peak set point threshold, the lighting load of the customer will be entirely powered by the utility through the AC-to-DC converter, and the storage battery 234 is being recharged under these conditions. This can be considered a first mode of operation of the power management system.
Assume now that the customer's demand has increased to 850 K watts, which is 50 K watts over the 800 K watt set point threshold set in the management system. Under such conditions, the lighting load controlled by the system will draw 50 K watts of power from the utility through the AC-to-DC converter 238 and 50 K watts of power from the storage battery. Thus, there is a proportional sharing of power to the load from the utility and the storage battery to provide power to the lighting or other load. This can be considered a second mode of operation of the system.
If customer demand increased to 1000 K watts, which is 200 K watts above the threshold, the lighting load will be powered entirely from the storage battery and not by the utility. This is a third “uninterrupatable” mode of operation of the system.
Preferably, the storage battery 234 is formed from a series connection of ten, 12 volt DC batteries. One form of battery, which is suitable for use, is a sealed, maintenance free lead acid Absolyte™ series of batteries manufactured by GNB, Inc.
The operation of the power management system will now be described. A stochastic or recurrent peak power demand is detected by the power transducer 110 . The voltage level of the output signal from the power transducer will increase, and this increase in voltage level will be averaged over a predetermined integration period by the integrator circuit 214 . The output signal of the integrator circuit will accordingly also increase in magnitude. If the output signal level of the integrator circuit 214 is greater than the threshold signal level of either set point circuit 228 , 232 connected to the system, the comparator or differential amplifier circuit 220 will sense this and provide an appropriate output signal to the AC-to-DC power supply 238 to reduce the power supply output voltage to below the potential of the storage battery 234 . Since the battery potential is greater than the power supply voltage, power from the battery 234 will be supplied to the load.
If electric power demand from the utility decreases, a corresponding decrease in the magnitude of the output signals from the power transducer 210 and the integrator circuit 214 will follow. If the output signal from the integrator circuit falls to or below the threshold level set by the set point circuits 228 , 232 , the comparator or differential amplifier circuit 220 will sense this and will provide the appropriate signal to the control input of the switching power supply 238 to increase the output voltage level of the power supply. If the supply's output voltage level is greater than the present or “spot” potential of the storage battery 234 , the load will again be fully served by the power supply, and current will also flow to the battery until the battery is fully charged. In this mode, no current will flow from the battery to the load.
Another form of the power management system is shown schematically in FIG. 13 . The power transducer 210 is connected to one or more of the customer's utility power lines., as shown in FIG. 12 , and has its output connected to the non-inverting input of an operational amplifier 260 configured as a non-inverting buffer amplifier. The output of the buffer amplifier 260 is connected to one side of a differential amplifier circuit including an operational amplifier 240 , a first input resistor 243 connected between the buffer amplifier output and the non-inverting input of the operational amplifier 240 , and another resistor 245 connected between the non-inverting input of the operational amplifier and ground. The differential amplifier includes another input resistor 244 connected to the inverting input of the operational amplifier 240 , a feedback resistor 242 connected between the output and inverting input of the operational amplifier and a feedback capacitor 262 connected in parallel with the feed back resistor. The input resistors 243 , 244 are preferably equal in value, as are the feedback resistor 242 and grounded resistor 245 , as in the previous embodiment. The feedback capacitor 262 is provided to slow the response time of the differential amplifier.
A manual set point threshold circuit includes a potentiometer 236 having its opposite legs connected between a positive voltage and ground and its wiper provided to the non-inverting input of an operational amplifier 264 configured as a non-inverting buffer amplifier. The output of the buffer amplifier 264 is provided to the other input resistor 244 of the differential amplifier.
The output of the differential amplifier is provided to a voltage-to-current converter. The voltage-to-current converter includes an NPN transistor 266 , a base resistor 268 connected between the output of the differential amplifier and the base of the transistor 266 , and an emitter resistor 270 and series connected diode 272 which together are connected between the emitter of the transistor and ground. The collector of the transistor 266 is connected to one end of a fixed resistor 274 and one end and the wiper of a multi-turn potentiometer 276 , whose other end is connected to ground. The remaining end of the fixed resistor 274 is connected to the adjust input of a series regulator 278 , such as Part No. TL783C manufactured by Texas Instruments and to one end of another fixed resistor 280 whose other end is connected to the output (OUT) of the regulator 278 .
As in the previous embodiment, the power management system includes an AC-to-DC converter comprising the regulator 278 mentioned previously, a full wave rectifier circuit consisting of two diodes 282 , 284 and a conventional pi filter consisting of two by-pass capacitors 290 , 292 and a series choke or inductor 294 , the filter circuit being connected to the output of the rectifier circuit. The output of the filter circuit is connected to one leg of a fixed resistor 296 , whose other leg is connected to the input (IN) of the regulator 278 and to the base of a PNP transistor 298 through a base resistor 100 . The emitter of the transistor 298 is connected to the output of the filter circuit, and the collector is connected to the base of an NPN power transistor 102 . A suitable power transistor 102 , which may be used, is Part No. TIPL762 manufactured by Texas Instruments. Of course, the power transistor is selected in accordance with the power requirements of the system. The collector of the power transistor 102 is connected to the emitter of its driving transistor 298 and to the output of the filter, and the emitter of the transistor 102 is connected to the output of the regulator 278 . Transistor 298 and 102 and their associated components form a current booster circuit.
The power management system shown in FIG. 13 further includes an isolation and distribution circuit consisting of three interconnected first, second and third diodes 250 , 252 , 254 as in the previously described embodiment illustrated by FIG. 12 . The output of the regulator 278 is connected to the anodes of first and third diodes 250 , 254 . The anode of the second diode 252 and cathode of the third diode 254 are connected to the positive terminal of a storage battery 234 used in the power management system, and the cathodes of the second and third diodes 252 , 254 are connected to the load 246 which is powered by the system.
The power management system shown in FIG. 13 operates in the following manner. When the power drawn from the utility is such that the output level of the transducer 210 is below the set point threshold level, the transistor 266 of the voltage-to-current converter is non-conducting. This effectively increases the resistance of the lower leg of a resistor divider network defined by resistor 280 , comprising the upper leg, and the combination of resistors 274 and the parallel combination of the multi-turn potentiometer 276 and the resistance of the voltage-to-current converter, which comprise the network's lower leg. Under such conditions, the voltage at the anode of the first diode 250 will be greater than the voltage at the anode of the second diode 252 , which is the voltage of the storage battery 234 . The first diode 250 will be turned on and the second diode 252 will be back biased so that power from the utility through the AC-to-DC converter, i.e., the full wave rectifier circuit, the filter and the current booster circuit, will be provided to the load 246 .
When the transducer 210 of the power management system senses an increase in utility power drawn by the customer, the output signal from the buffer amplifier 260 will exceed the magnitude of the output signal of the threshold signal's buffer amplifier 264 . In response, the differential amplifier will provide a positive voltage output signal, which will cause the transistor 266 of the voltage-to-current converter to conduct current. This effectively lowers the resistance of the lower leg of the resistor divider network, which in turn decreases the voltage on the anode of the first diode 250 . If the voltage on the anode of the first diode 250 decreases to a point where the second diode 252 is forward biased, current will flow from the storage battery 234 to the load. As now less power is drawn from the utility, the output voltage from the power transducer 210 will decrease, which affects the output voltage of the differential amplifier and the current drawn through the collector of the voltage-to-current converter transistor 266 . This will change the voltage on the anode of the first diode 250 to a point where there is a proportional sharing of power from the storage battery and from the utility. Thus, the power management system acts as a servo system with feedback and has a self-leveling capability.
As can be seen from the above description, the power management system can be easily implemented in a customer facility with little or no rewiring. Because the main distribution panel 202 is usually connected to a second, lighting distribution panel 204 , the interconnection between the two can be broken and connected to the power management system. Also, fluorescent lighting, which may represent approximately 40% of the total load for some utility customers, is a particularly attractive load to work in conjunction with the power management system. The lighting load remains fairly constant throughout the day and, therefore, the power management system parameters may be easily optimized for operating such a load. In addition, many of the electronic ballasts currently, and increasingly, used in fluorescent lighting will function on either direct current (DC) or alternating current (AC). If fluorescent lighting, either electronically ballasted or magnetically ballasted, is to be controlled by the system and powered by AC, this may be accomplished by using an inverter 110 interconnected between the output of the power isolation and distribution circuit 248 (and the negative terminal of the AC-to-DC converter 0 . 38 ) and the lighting distribution panel 204 , as shown by dashed lines in FIG. 12 . Accordingly, fluorescent and other lighting is perfectly suited for operation with the power management system.
With reference to FIG. 14 note that the circuit shown largely parallels FIG. 13 wherein rectification is effected by the diodes 282 and 284 . They feed the TEE circuit 294 , 290 , 292 of the voltage regulator section (so labeled) operating in conjunction with the control interface (so labeled) to output DC at the junction A. Thus, an important objective is realized, namely, that the charge level of the storage battery means SB to service an intrinsic DC load means such as 346 in FIG. 14 or the electronically (DC) ballasted fluorescent lighting circuit FL in FIG. 15 is maintained at the desired level. Note that the three modes of operation as disclosed in Applicant's U.S. Pat. No. 5,500,561 obtain.
When AC input is present, the voltage regulator function illustrated in FIG. 14 is one means for maintaining the charge level of the storage battery means SB. contained within the module M and which is connected to the junctions J 1 and J 2 . The lighting load 346 is, of course, an intrinsic DC load means such as the looped LIGHTS circuits FL looped between the ground buss GB and the circuit breakers B 5 and B 6 which are connected to the neutral buss NB as in FIG. 15 . The photo-voltaic panel means PV and the inverter means INV are shown in FIG. 14 . It will also be understood that although the electric distribution box is not illustrated fully in FIG. 14 , this is done for 0.5 simplicity to avoid overcrowding of the Figure.
FIG. 15 shows the electric distribution box EDB in simplified and uncluttered form and is principally directed to illustrating the concept of ganged circuit breakers and of looping of an intrinsic DC load means as well the use of a load source means. The box EDB is outlined and the ground buss GB, the neutral buss NB and the power buss P 2 are all designated. The DC ballasted fluorescent lighting intrinsic DC load means FL comprises an example of a distributor box DBD emanating from the box EDB. Each looping WDBD 54 and WDBD 56 is between the neutral buss NB (−DC) through the circuit breaker means B 5 and B 6 to the ground buss GB (+DC). Four electrical outlet means E 01 , E 02 , E 03 and E 04 are illustrated, all identical, with the two wirings W 20 connected with the power buss P 2 through the respective circuit breaker means B 1 and B 3 . Similarly, the two wirings W 22 are connected with the neutral buss NB through the respective circuit breaker mans B 2 and B 4 . The circuit breakers B 1 and B 2 “belong” to an AC path and a DC path, respectively, and the circuit breakers B 3 and B 4 similarly “belong”.
The DC power sources are illustrated as the DC generator and the photo-voltaic panel means PV which, after regulation at the regulator 440 , passes through the isolating diode D 2 to the junction A to which the positive side of the DC generator DCPS is connected through the isolating diode D 1 . The junction A is connected to the ground buss GB through the circuit breaker B 8 whereas the AC input from the inverter 450 is connected to the neutral buss NB by means of the wiring W 50 and to the circuit breaker B 7 through the wiring W 52 . The looping of the intrinsic DC load means effectively doubles the current carrying capacities of the associated wirings whereas the ganging of the AC and DC paths as to circuit breaker means allows the dual voltage aspect to be carried out with increased safety.
To reiterate some of the above, the modular concept of this invention is very important in that it involves the provision of separate entities which are the storage battery means SB and the filter capacitor means FC. The storage battery means SB has a very large battery equivalent capacitance consistent with an excellent AC path to ground and the filter capacitor means FC has a very small capacitance consistent with a limited AC path to ground and being sized in capacitance wherein the capacitive reactance xc is low enough to pass sufficient current to keep both the worst case fault currents well below any shock hazards and to allow sufficient current flow to trip the relevant circuit breaker(s) in the event of an appliance short circuit. As noted, the capacitance of the filter capacitor FC should be in the order of 50 microfarads.
FIG. 16 is directed to a circuit, which embodies a switching type converter of very high efficiency and is a preferred form of converter because this type of DC-to-DC power supply represents high efficiency contemporaneously possible. FIG. 16 illustrates input mechanisms, some of which are not designated by reference characters but which are designated as to function, and also illustrates output mechanisms, none of which are designated by reference characters but which are designated as to function. In all such cases, the meanings should be clear and the additional descriptive material detailing the mechanisms and reference characters are believed to be unnecessary.
The block enclosed in dashed lines and designated by the reference character 501 is a typical full wave rectifier bridge circuit (i.e., the opposite of an inverter) feeding the capacitor 505 at the junction 501 ′ and whose purpose is to reduce the rectified ripple component of the circuit 501 and to provide filtered DC input voltage, present between the junction 501 ′ and the conductor 501 v to the converter means.
The converter circuit shown, downstream of and as fed by filtered DC from the rectifier circuit 501 has junctions 521 ′ and 521 ″ within the section 521 between which the resistor/capacitor pair 521 r and 521 c are connected and which pair provide the further junction 521 ′″. The junction 521 ′″ is connected to the conductor 521 v which supplies the pulse width modulator 503 with positive voltage Vcc, and this junction feeds the diode 521 d 1 having junctions with the parallel resistor/capacitor pair which are connected between the diode 521 d 2 and the junction 521 ″.
The converter employs a pulse width modulator PWM, indicated at 503 , controlling the switching transistor circuit 508 to impress transient voltage spikes present on the conductor 508 v through the primary of the transformer 506 to cycle current to the primary windings L 1 and L 2 of the transformer 506 whereby “ac is generated as an intermediate process in the flow of energy” as is defined in the above definition of “converter”. The secondary side of the transformer 506 is represented by the windings L 3 and L 4 .
The circuit 509 is an optical isolation link between the pulse width modulator 503 and the control means 522 on the secondary side of the transformer 506 which allows control voltage on the conductor 509 v emanating from the pulse width modulator 503 on the primary side of the transformer 506 to provide an input to the control means 522 on the secondary side to influence the pulse width modulator PWM 503 without current leakage back from the secondary circuit. Typically, the frequency of conversion effected by the transformer 506 will be 20,000-100,000 Hz, which dictates the need for the special capacitor 517 to absorb these transients, the capacitance of the capacitor 517 being typically about 1 microfarad when used.
A secondary winding L 4 drives the circuit 514 which, similarly t6 the rectifier 501 plus the filtering of the capacitor 505 , provides a DC output, in this case the proper DC input to the control means 522 at the conductor 514 v . The control means 522 has an output conductor 522 o connected to the optical link 510 for controlling the three modes of operation of voltage control in accord with the principles of my prior applications. That is to say, when the optical isolator 510 link is “on”, modes which permit DC current to flow from the photovoltaic means 520 are operative, i.e., either or both DC power input from the means 520 alone and partial or shared DC power input from the means 520 . When the optical isolator 510 link is “off”, the remaining mode, DC power input solely from another source (i.e., no photovoltaic input) is effected.
The modes are controlled by the DC voltage prevailing across the junctions J 1 and J 2 (or the presence of a rechargeable DC mechanism such as a storage battery means connected to these junctions) in which case, mode 1 , DC power input to the rechargeable DC mechanism alone, mode 2 , shared DC power input, and mode 3 no DC power input to the rechargeable DC mechanism are the order of the day. That is to say, when the conductors 523 and 524 are connected to one of the DC sources illustrated in FIG. 16 , or to a DC power source such as DCPS in FIG. 15 , the system will be fully operative for the purposes intended.
Stated another way, the DC voltage applied to the storage means will depend upon the feedback influenced by the resistors 336 , 342 , 343 , 344 , 345 , 368 , 370 , 374 and 376 in FIG. 14 or by the resistors including 511 , 512 , 513 and 515 in FIG. 16 .
This is true even if the system according to this invention is operated on the barest of input. For example, in locations where either AC or DC power is available only part of the time, or is available on site only from mechanism thereat, some configuration disclosed in the drawing Figures herein will be effective to provide DC power supply to the storage battery means. This, therefore, constitutes a universal power system.
Other modifications may be made to the present invention without departing from the scope of the invention, as noted in the appended claims. | A high efficiency lighting system maintains normal lighting conditions by lighting fixtures requiring DC electrical power. A power control device receives AC electrical power from a public utility converts AC power to DC power and delivers low voltage DC electrical power to lighting fixtures. A standby battery is provided to maintain power during power outages. Optionally, a photovoltaic DC electrical power source may be connected to the power control device, to provide alternate DC electrical power. In a further embodiment, a gas driven cogenerator unit may supply DC electrical power. | 8 |
RELATED APPLICATION
This application is a divisional of prior U.S. application Ser. No. 11/399,215, filed Apr. 6, 2006 now abandoned, which is a continuation of prior U.S. application Ser. No. 10/460,899, filed Jun. 12, 2003 now U.S. Pat. No. 7,058,251, the entire contents of which are hereby incorporated by reference herein and made a part of this specification, and claims the benefit of U.S. Provisional Application Nos. 60/388,358 filed Jun. 12, 2002, and 60/397,944 filed Jul. 23, 2002, the disclosures of which are also incorporated fully herein by reference.
FIELD OF THE INVENTION
This invention relates to the field of optical communications, and more particularly, to a wavelength selective optical switch for use in optical multiplexing.
BACKGROUND OF THE INVENTION
For several decades, fiber optics have been used for communication. Specifically, fiber optics are used for data transmission and other telecommunication applications. Despite the enormous information carrying capacity of fiber, as compared to conventional copper cable, the high cost of installing fiber optics presents a barrier to full implementation of fiber optics, particular as the “last mile”, from the central office to residences and businesses.
One method of increasing carrying capacity without incurring additional installation costs has been to multiplex multiple signals onto a single fiber using various methods, such as time division multiplexing, where two or more different signals are carried over the same fiber, each sharing a portion of time. Another more preferred multiplexing method is wavelength division multiplexing (WDM), where two or more different wavelengths of light are simultaneously carried over a common fiber.
Wavelength division multiplexing can separate a fiber's bandwidth into multiple channels. Dividing bandwidth into multiple discreet channels, such as 8, 16, 40, or even as many as 160 channels, through a technique referred to as dense channel wavelength division multiplexing (DWDM), is a relatively lower cost method of substantially increasing telecommunication capacity, using existing fiber optic transmission lines. Techniques and devices are required, however, for multiplexing the different discreet carrier wavelengths. That is, the individual optical signals must be combined onto a common fiber-optic line or other optical waveguide and then later separated again into the individual signals or channels at the opposite end or other point along the fiber-optic cable. Thus, the ability to effectively combine and then separate individual wavelengths (or wavelength sub-ranges) is of growing importance to the fiber-optic telecommunications field and other fields employing optical instruments.
Optical multiplexers are known for use in spectroscopic analysis equipment and for the combination or separation of optical signals in wavelength division multiplexed fiber-optic telecommunications systems. Known devices for this purpose have employed, for example, diffraction gratings, prisms and various types of fixed or tunable filters.
Approaches for selectively removing or tapping a channel, i.e., selective wavelengths, from a main trunk line carrying multiple channels, i.e., carrying optical signals on a plurality of wavelengths or wavelength sub-ranges, is suggested, for example, in U.S. Pat. No. 4,768,849 to Hicks, Jr. Hicks, shows filter taps, as well as the use of gangs of individual filter taps, each employing high performance, multi-cavity dielectric pass-band filters and lenses for sequentially removing a series of wavelength sub-ranges or channels from a main trunk line. The filter tap of Hicks, returns a multi-channel signal to the main trunk line as it passes the desired channel to a branch line. One known demux is disclosed in Pan et al., U.S. Pat. No. 5,652,814, FIG. 25. In Pan et al., the WDM input signal is cascaded through individual filter assemblies, consisting of a fiber collimator, thin film filter, and a fiber-focusing lens. Each filter is set for a given wavelength. However, aligning the fibers for each wavelength is costly and errors in the alignment contribute significantly to the system losses. Further, FIG. 13 of Pan et al. teaches the use of a dual fiber collimator, thin film filter, and a dual fiber focusing lens to selectively DROP and ADD a single wavelength or range of wavelengths. As discussed above, aligning the collimators is expensive.
Polarization dependent loss (PDL) is also a problem in WDM system because the polarization of the light drifts as it propagates through the fiber and furthermore this drift changes over time. Thus, if there is PDL in any component, the drifting polarization will change the signal level, which may degrade the system operation.
Other multiplexer devices may be employed to add or drop channels in WDM systems. These systems are commonly known as optical add/drop multiplexers, or OADM. Another OADM, disclosed by Mizrahi in U.S. Pat. No. 6,185,023, employs fiber Bragg gratings to demux and mux signals in a WDM system. This method requires optical circulators and multiple components.
However, the multi channel OADM designs discussed above are not programmable by the end user. That is, each multiplexer is designed and manufactured to mux (add) specific channels; or when used in reverse each multiplexers is also designed and manufactured to demux (drop) specific channels. This limitation mandates that the optical system's parameters be fixed before installation. Changes are not possible without replacing the fixed optical multiplexers with different designed multiplexers. This is expensive.
One known programmable OADM is discussed in Boisset et al, International Publication No. WO01/13151. In Boisset et al., the desired add/drop channel is programmed by translating a segmented filter. To achieve this translation however, a large mechanical mechanism is employed. A further limitation to Boisset et al. is that only a single channel may be added or dropped per device. Designers may employ multiple devices, deployed in series, and programmed as necessary to add/drop the correct channel; however, this approach requires multiple devices and has multiple points of failure. Furthermore, the size of such a device would be overly large and therefore not practical for many applications where space is limited.
An OADM disclosed by Patel et al., U.S. Pat. No. 5,414,540 uses bulk gratings to demultiplex and multiplex WDM input and output signal and compact liquid crystal switches. Because the device uses polarization to switch the light path, the arbitrarily polarized incident beam must be converted into a singular polarization prior to switching by the liquid crystal. Patel teaches the use of a birefringent crystal and a Wollaston prism to separate the incident beam into two polarizations state located between the focusing lens and the liquid crystal. While the OADM disclosed by Patel is relatively compact; it only provides 2×2 switching for each wavelength. There is an Input and Add channel that may be selectively sent to either the Output or Drop channel. If higher dimensionality switching is required, then additional components are required. The additional components require additional space, add attenuation, and add cost to the system. A 2×2 switch has four sub beams incident on the liquid crystal (because of the conversion from an arbitrary polarized beam to a single polarization for the liquid crystal switch) and four sub beams leaving the liquid crystal. Thus, the aperture of the lens focusing the light on the grating must be a minimum of 4× larger than that required for a single sub beam in one polarization.
An OADM disclosed by Ranalli et al., U.S. Pat. No 6,285,500, that uses bulk gratings to demultiplex and multiplex WDM input and output signal and compact liquid crystal switches. Because the device uses polarization to switch the light path, the arbitrarily polarized incident beam must be converted into a singular polarization prior to switching by the liquid crystal. Ranalli teaches the use of half-wave plates and a thin film polarization beamsplitter located before the lens that focuses light onto the liquid crystal. Because of the optical arrangement, the aperture of the lens focusing the light on the grating must be a minimum of 2× larger than that required for a single sub beam in one polarization. While the OADM disclosed by Ranalli is relatively compact; it only provides 2×2 switching for each wavelength. There is an Input and Add channel that may be selectively sent to either the Output or Drop channel. If higher dimensionality switching is required, then additional components are required. The additional components require additional space, add attenuation, and add cost to the system.
A OADM disclosed by Patel et al., U.S. Pat. No. 6,327,019, uses bulk gratings to demultiplex and multiplex WDM input and output signal and compact liquid crystal switches. The OADM disclosed by Patel provides for dual 2×2 switching for each wavelength. There are two Input and two Add channels that may be selectively sent to either the two Output or two Drop channels. If higher dimensionality switching is required, then additional components are required. The additional components require additional space, add attenuation, and add cost to the system. Because liquid crystals use polarization to switch the light path, the arbitrarily polarized incident beam must be converted into a singular polarization prior to switching, which doubles the required aperture of the lens. Thus, the dual 2×2 switch has eight sub beams incident on the liquid crystal and eight sub beams leaving the liquid crystal. Thus, the aperture of the lens focusing the light on the grating must be a minimum of 8× larger than the aperture required for single incident beam in one polarization.
An OADM disclosed by Aksyuk, et al, U.S. Pat. No. 6,204,946 uses a bulk grating to demultiplex and multiplex WDM input and output signal and Micro Electrical Mechanical Systems (MEMS) to provide the switching. This is another relatively compact switch, but it only provides 2×2 switching for each wavelength. There is an Input and Add channel that may be selectively sent to either the Output or Drop channel. If higher dimensionality switching is required, then additional components are required. The additional components require additional space, add attenuation, and add cost to the system. Because Aksyuk uses circulators to separate the Input and Add channels from the Output and Drop channels, the aperture of the lens focusing the light on the grating must be a minimum of 2× larger than the of a single incident beam.
Another known programmable OADM is discussed Tomlinson, U.S. Pat. No. 5,960,133, uses a bulk gratings to demultiplex and multiplex WDM input and output signal, and MEMS mirrors to switch. The OADM disclosed by Tomlinson is programmable and provides for dual 2×2 switching. Tomlinson teaches a switch that does not require the use of circulators, potentially increasing the system efficiency. However, the aperture of the lens focusing the light on the grating must be a minimum of (1+Sqrt[2])× larger than the of a single incident beam for a 2×2 switch. Furthermore, for a dual 2×2 without circulators, the aperture of the lens focusing the light on the grating must be a minimum of Sqrt[10]× larger than that of a single incident beam. Thus, the size and expense of the focusing lens required grows quickly when moving from a single to dual switching.
A programmable optical multiplexer/demultiplexer, disclosed by Marom et al, in US Pat. App. 02/0196520, independently assigns every input optical channel in a signal to depart from any desired output port, which provides the functionality of 1×N switching for every wavelength. Marom teaches the use of a bulk grating to multiplex/demultiplex WDM input and output signal, and MEMS mirrors to switch. The demultiplexer device can also be operated in the reverse direction, and thus achieve programmable optical multiplexer functionality. However, the size and expense of the lens required by the demultiplexer also grows linearly with port count. A 1×5 port programmable optical multiplexer/demultiplexer requires a lens to focus light on the MEMs mirrors with an aperture at least 5× as large as that of a single incident beam.
Optical gratings are a periodic structure, which diffract light according to the wavelength. They can be used in either reflection or transmission. Gratings can be produce by modulating the surface height of a substrate or by modulating the index of refraction of a structure.
The spectral resolving power, R=λ/Δλ, of a grating is a measure of its ability to separate adjacent spectral lines, where A is average wavelength of a line and Δλ is the limit of resolution. The theoretical resolving power is
R=Nd cos Γ(sin α+sin β)/λ
where N is the number of groves, d is the groove spacing, Γ is the angle between the incident light path and the plane perpendicular to the groves, α is the angle of incidence on the grating and β is the angle of diffraction. If the grating is planar and the groove spacing is uniform, then the resolving power is proportional to the ruled with of the grating, N d. Spectral resolving power is an important design parameter; the greater the resolving power the greater the optical separation between channels, and ultimately the channels a grating-based system can accommodate. For low-loss transmission of OC-768 channels and a channel spacing of 100 GHz, it is preferred that the resolution be 20 GHz or finer.
Of course, a larger grating can be employed to increase the spectral resolving power, however, that requires a combination of more physical space and faster or longer focal length lenses that are more expensive. Another approach has been to decrease the spacing of the grating grooves, d. However, the maximum theoretical efficiency of the grating decreases for small groove separations. When the separations between the grooves spacing is comparable to the wavelength of light, it is possible to get gratings that operate with high efficiency (>90%) for any incident polarization state. As the groove spacing approaches half the wavelength of light, it is possible to get high efficiency for only light polarized parallel to the grooves. For even smaller grooves separations, it is not possible to get high efficiency in either polarization state. Thus, there is a practical limit to increasing spectral resolving power through decreased grating groove separations. The relationship between grating efficiency, polarization, and groove shape is well known in the art and described in Diffraction Grating Handbook, Ch. 9, 4th Ed, Richardson Grating Laboratory, C. Palmer, (2000), which is hereby incorporated by reference. Each bulk diffraction grating device requires a minimum number of grating grooves to achieve a given spectral resolution. The minimum size is determined by the optical configuration of the device and the grating parameters.
One desired application for optical multiplexing and demultiplexing systems is in optical wavelength switch. An optical wavelength switch demultiplexes optical signals, switches the signals, and then and multiplexes to a plurality of optical ports.
The ability to switch to a number of optical ports in wavelength switches introduces another limiting design factor. In order to switch to a number of physical ports the size of the device must not only accommodate the space needed for the ports, but the optics must also direct the optical signals to those ports. As the number of ports increases the optical directing means (typically a moveable mirror) must be capable of directing the optical beams across a larger physical area where the optical ports are located. Also, as the optical beams must exit the ports within an acceptance angle so as to be coupled into the optical fiber, the ports must be physically located within a certain placement angle from the directing means. As the placement angle increases, the optical directing means generally becomes more expensive and the insertion loss increases. An additional lens may be used to focus the beam—however, this adds component cost and size to the device.
If the optical beams inside the device are made larger so as to increase spectral resolution the device size must increase, and in some cases larger lenses must be used. For example, an optical switch of the type disclosed by Marom et al. US 2002/0196520 A1, with one input port and four output ports (1×4) might be capable of switching 64 wavelengths spaced at 100 GHz. If the same design were used to switch 16 ports the grating and the grating aperture would likely need to be 4× larger to accommodate 100 GHz channels or if the grating was the same size, the system could switch 16 wavelength channels spaced at 400 GHz. The device disclosed by Marom cannot provide adequate spectral resolution for a large number of ports and a large number of wavelengths using small compact lenses that are easy to manufacture.
An optical wavelength switch disclosed by Waverka et al. WO 01/37021 uses a bulk diffraction grating and MEMS mirrors to provide 1×N switching. However, this design has a major drawback. Because the image is translated at the spectral focal plane by the MEMS mirrors, the incident angle on the grating changes with switch position, which in turn changes the angular dispersion provided by the grating. Thus, the device is unable to achieve adequate spectral resolution for a large number of ports and a large number of wavelengths with low losses. Waverka also teaches the use of cylindrical optics to produce an elliptical beam that minimizes the size of the grating. However, because the cylindrical optics are used symmetrically to both collimate light for the grating and to focus the light on the switch array, the footprint of the optical beam at the switch is a very high aspect ratio ellipse. Thus, very long thin, hard to fabricate switches are required.
It is an object of the present invention to provide improved optical switching that reduce or wholly overcome some or all of the aforesaid difficulties inherent in prior known devices. Particular objects and advantages of the invention will be apparent to those skilled in the art, that is, those who are knowledgeable and experienced in this field of technology, in view of the following disclosure of the invention and detailed description of certain preferred embodiments.
SUMMARY OF THE INVENTION
In accordance with a first aspect of the invention, a wavelength selective optical switch, can establish a reconfigurable connection between any two fibers from a plurality of fibers in a fiber array, independently for each optical wavelength that enters the switch. One of a plurality of cylindrical lenses receives a first multi-channel optical signal from an optically coupled fiber in the array, the first multi-channel optical signal is directed through an anamorphic lens to a grating. The grating diffracts the first multi-channel optical signal according to the wavelengths of each individual optical channel, and directs each channel through a rotationally symmetric lens that focuses the individual optical channels near one of a plurality of programmable mirrors. Each mirror is associated with a particular individual optical channel. Depending upon the programmed state of the mirror, the individual optical channel is directed to any one of the fibers in the fiber array by way of the rotationally symmetric lens, the grating, the anamorphic lens, and one of the plurality of cylindrical lenses. By changing the programmed state of the mirror, the individual optical channel may be switched to any of the fibers in the fiber array.
The invention may be used as a programmable optical demultiplexer, wherein one of the plurality of cylindrical lenses receives a first multi-channel optical signal from an optically coupled fiber in the array, the first multi-channel optical signal is directed through the anamorphic lens to the grating. The grating diffracts the first multi-channel optical signal according to the wavelengths of each individual optical channel, and directs each channel through a rotationally symmetric lens that focuses the individual optical channels near one of a plurality of programmable mirrors. Each mirror is associated with a particular individual optical channel. Depending upon the programmed state of the mirrors, individual optical channels are directed to any one of the fibers in the fiber array by way of the rotationally symmetric focusing lens, the grating, the anamorphic lens, and one of the plurality of cylindrical lenses. By changing the programmed state of the mirrors, any of the individual optical channels may be switched to any of the fibers in the fiber array. Further, in the case where two or more of the individual optical channels are switched to a single fiber, upon illuminating the grating the two or more individual optical channels are multiplexed into a second multi-channel light signal.
The device may also be operated in the “opposite direction” as a programmable multiplexer; that is two or more of the plurality of cylindrical lenses each receives one or more different individual optical channels from optically coupled fibers in the array, the individual optical channels are directed through the anamorphic lens to the grating. The grating diffracts the first multi-channel optical signal according to the wavelengths of each individual optical channel, and directs each channel through a rotationally symmetric lens that focuses the individual optical channels near one of a plurality of programmable mirrors. Each mirror is associated with a particular individual optical channel. Each of the mirrors is programmed to reflect each of the individual optical channels to any one of the fibers in the fiber array by way of the rotationally symmetric focusing lens, the grating, the anamorphic lens, and one of the plurality of cylindrical lenses. By changing the programmed state of the mirrors, all of the individual optical channels may be switched to any of the fibers in the fiber array.
In accordance with the first aspect of the invention, the programmed state of the mirrors is such that a mirror connection may be established at any place along the fiber array. In this regard, the device can be programmed to establish optical connectivity, for each optical channel, between any of the fibers in the array. That is the device can operate as an N×1×M switch; directing N unique individual optical channels received from one fiber in a fiber array to any of the M fibers in the fiber array.
The device may also direct two or more individual optical channels centered at the same wavelength and received from two or more fibers in the fiber array to other fibers in the array. However, the switching matrix is more restrictive as the same mirror is used for the direction of all the individual optical channels centered at the same wavelength. In this manner, each of the individual optical channels centered at the same wavelength are directed to the fiber in the fiber array that is opposite the mirror's connection. For example, consider a nine port device coupled to a nine fiber array (the consecutive fibers numbered 1 through 9) which receives a first individual optical channel centered at wavelength x on port 1 , and receives a second individual optical channel centered at wavelength x on port 2 . If the corresponding mirror connection for wavelength x is set such that the light at wavelength x entering the switch from fiber 3 also leaves from fiber 3 , then the first individual optical channel at wavelength x will be directed to fiber 5 , and the second at wavelength x to fiber 4 . In this manner, the device does not operate as an N×1×M switch, but still provides numerous switching options. Such options will be clear to one skilled in the art.
In accordance with a second aspect of the invention, a wavelength selective optical switch, can establish a reconfigurable connection between any two fibers from a plurality of fibers in a fiber array, independently for each optical wavelength that enters the switch. One of a plurality of cylindrical lenses receives a first multi-channel optical signal from an optically coupled fiber in the array, the first multi-channel optical signal is directed through an anamorphic lens, to a beam splitter. The beam splitter separates light that is s-polarized from light that is p-polarized, and directs both out of the beam splitter through a first and second quarter waveplate. The s-polarized light illuminates a first grating, and the p-polarized light illuminates a second grating. The gratings diffract the respective s-polarized and p-polarized first multi-channel optical signal according to the wavelengths of each individual optical channel, and direct the respective s-polarized and p-polarized light of each individual optical channel back through the quarter waveplate into the beam splitter, which recombines the s-polarized and p-polarized light of each channel and directs the individual optical channels through a rotationally symmetric lens that focuses the individual optical channels near one of a plurality of programmable mirrors. Each mirror is associated with a particular individual optical channel. Depending upon the programmed state of the mirror, the individual optical channel is directed to any one of the fibers in the fiber array by way of the rotationally symmetric lens, the beam splitter, waveplates and gratings, the beam splitter, anamorphic lens, and one of the plurality of cylindrical lenses. By changing the programmed state of the mirror, the individual optical channel may be switched to any of the fibers in the fiber array.
The device may also be operated in the “opposite direction” as a programmable multiplexer; that is two or more of the plurality of cylindrical lenses each receives one or more different individual optical channels from optically coupled fibers in the array, the individual optical channels are directed through the anamorphic lens to the beam splitter. The beam splitter separates the s-polarized and p-polarized states and directs each to the first and second gratings. The gratings diffracts the first multi-channel optical signal according to the wavelengths of each individual optical channel, and directs each channel back through the beam splitter recombining the s-polarized and p-polarized states, and directing the individual optical channel through the rotationally symmetric lens that focuses the individual optical channels near one of a plurality of programmable mirrors. Each mirror is associated with a particular individual optical channel. Each of the mirrors is programmed to reflect each of the individual optical channels to any one of the fibers in the fiber array. By changing the programmed state of the mirrors, all of the individual optical channels may be switched to any of the fibers in the fiber array.
In accordance with the second aspect of the invention, the programmed state of the mirrors is such that a mirror connection may be established at any place along the fiber array. In this regard, the device can be programmed to establish optical connectivity, for each optical channel, between any of the fibers in the array. That is the device can operate as an N×1×M switch; directing N unique individual optical channels received from one fiber in a fiber array to any of the M fibers in the fiber array.
The device may also direct two or more individual optical channels centered at the same wavelength and received from two or more fibers in the fiber array to other fibers in the array. However, the switching matrix is more restrictive as the same mirror is used for the direction of all the individual optical channels centered at the same wavelength. In this manner, each of the individual optical channels centered at the same wavelength are directed to the fiber in the fiber array that is opposite the mirror's connection. For example, consider a nine port device coupled to a nine fiber array (the consecutive fibers numbered 1 through 9) which receives a first individual optical channel centered at wavelength x on port 1 , and receives a second individual optical channel centered at wavelength x on port 2 . If the corresponding mirror connection for wavelength x is set such that the light at wavelength x entering the switch from fiber 3 also leaves from fiber 3 , then the first individual optical channel at wavelength x will be directed to fiber 5 , and the second at wavelength x to fiber 4 . In this manner, the device does not operate as an N×1×M switch, but still provides numerous switching options. Such options will be clear to one skilled in the art.
In accordance with several aspects of the invention one or more wave plates may be employed to reduce polarization dependent loss (PDL). The one or more wave plates rotates the polarization so that light that is s-polarized on a first pass is p-polarized on a second pass and there is no net polarization dependent loss (PDL) for light traveling through the device. Similarly, a polarization converter such as a rutile crystal may be used in combination with wave plates to reduce PDL.
In accordance with several aspects of the invention, the grating or gratings may operate at or near Littrow to increase the diffraction efficiency. In accordance with several aspects of the invention one or more transmission gratings may be employed. In accordance with several aspects of the invention, a beam displacer made of birefringent crystals or multi-layer coated polarization beamsplitters may be employed to separate and combine optical beams. Different aspects of the invention may also be employed together.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1(A) is a perspective view of a first embodiment of a wavelength selective optical switch detailing the optical paths through the device.
FIG. 1(B) is a perspective view of a first embodiment of a wavelength selective optical switch detailing the optical paths through the device.
FIG. 1(C) is a perspective view of a first embodiment of a wavelength selective optical switch detailing the optical paths through the device.
FIG. 2(A) is a perspective view of a first embodiment of a wavelength selective optical switch detailing the optical paths through the device.
FIG. 2(B) is a perspective view of a first embodiment of a wavelength selective optical switch detailing the optical paths through the device.
FIG. 2(C) is a perspective view of a first embodiment of a wavelength selective optical switch detailing the optical paths through the device.
FIG. 3(A) is a perspective view of a second embodiment of a wavelength selective optical switch detailing the optical paths through the device.
FIG. 3(B) is a perspective view of a second embodiment of a wavelength selective optical switch detailing the optical paths through the device.
FIG. 3(C) is a perspective view of a second embodiment of a wavelength selective optical switch detailing the optical paths through the device.
FIG. 4 is a perspective view of a second embodiment of a wavelength selective optical switch detailing the optical polarization states at various locations within the device.
FIG. 5(A) is a perspective view of a third embodiment of a wavelength selective optical switch detailing the optical paths through the device.
FIG. 5(B) is a perspective view of a third embodiment of a wavelength selective optical switch detailing the optical paths through the device.
FIG. 5(C) is a perspective view of a third embodiment of a wavelength selective optical switch detailing the optical paths through the device.
FIG. 6(A) is a perspective view of a fourth embodiment of a wavelength selective optical switch detailing the optical paths through the device.
FIG. 6(B) is a perspective view of a fourth embodiment of a wavelength selective optical switch detailing the optical paths through the device.
FIG. 6(C) is a perspective view of a fourth embodiment of a wavelength selective optical switch detailing the optical paths through the device.
FIG. 7(A) is a perspective view of a fifth embodiment of a wavelength selective optical switch detailing the optical paths through the device.
FIG. 7(B) is a perspective view of a fifth embodiment of a wavelength selective optical switch detailing the optical paths through the device.
FIG. 7(C) is a perspective view of a fifth embodiment of a wavelength selective optical switch detailing the optical paths through the device.
FIG. 8(A) is a perspective view of a sixth embodiment of a wavelength selective optical switch detailing the optical paths through the device.
FIG. 8(B) is a perspective view of a sixth embodiment of a wavelength selective optical switch detailing the optical paths through the device.
FIG. 8(C) is a perspective view of a sixth embodiment of a wavelength selective optical switch detailing the optical paths through the device.
FIG. 8(D) is a perspective view of a sixth embodiment of a wavelength selective optical switch detailing the optical paths through the device.
FIG. 9(A) is a perspective view of a seventh embodiment of a wavelength selective optical switch detailing the optical paths through the device.
FIG. 9(B) is a perspective view of a seventh embodiment of a wavelength selective optical switch detailing the optical paths through the device.
FIG. 9(C) is a perspective view of a seventh embodiment of a wavelength selective optical switch detailing the optical paths through the device.
FIG. 9(D) is a perspective view of a seventh embodiment of a wavelength selective optical switch detailing the optical paths through the device.
FIG. 10 is a perspective view of a seventh embodiment of a wavelength selective optical switch detailing the optical polarization states at various locations within the device.
DETAILED DESCRIPTION OF THE INVENTION
The wavelength selective optical switch of the invention has numerous applications, including use in fiber optic telecommunications systems. For purposes of illustration, the embodiments described below detail demultiplexing, switching, and multiplexing in a multi-channel fiber optic telecommunication systems. Exemplary references to an optical channel, or simply to a channel, should be understood to mean an optical signal with a centered wavelength and an upper and lower wavelength. Channel spacing is measured from the center of the first channel to the center of an adjacent channel.
A two channel grating-based optical switch, employing one embodiment of the invention, is detailed in FIG. 1(A) , FIG. 1(B) , and FIG. 1(C) . FIG. 1(A) , FIG. 1(B) , and FIG. 1(C) detail different views of the same device. It is of note that while only two channels are used in this example, a substantially larger number of channels and optical ports may be employed. The wavelength selective optical switch allows for demultiplexing, multiplexing and switching separate optical channels to any one of a plurality of optical ports. The wavelength selective optical switch of FIG. 1 may be dynamically programmed to demultiplex, multiplex and switch any combination of wavelengths to any of a plurality of optical ports.
A first embodiment of the wavelength selective optical switch device of FIG. 1(A) , FIG. 1(B) , and FIG. 1(C) comprises a Cylindrical Lens Array 103 optically coupled to an Input Fiber 101 , an Anamorphic Lens 105 , a Grating 109 , a Rotationally Symmetric Lens 111 , a Array of Programmable Mirrors 113 , a first Output Fiber 101 - a , and a second Output Fiber 101 - b . A cylindrical lens has at least one surface that is formed like a portion of a cylinder
z ( x )= cx^ 2/{1+Sqrt[1−(1 +k ) c^ 2 x^ 2 ]}+Ax^ 4 +Bx^ 6 +Cx^ 8+ Dx^ 10
where z(x) is the sag, c is the curvature at the pole of the surface, x is the distance from the center of the lens along the x-axis, k is the conic constant, and A, B, C, D are aspheric coefficients. Note that in this case that sag is independent of the y-coordinate. An anamorphic lens, usually having one more cylindrical surfaces, has a different magnification along mutually perpendicular meridians. The device of FIG. 1 may be mounted within an enclosure optimized for optical transmission, including a gas-filled enclosure, or the like.
Cylindrical Lens Array 103 , Anamorphic Lens 105 , and Rotationally Symmetric Lens 111 may be comprised of multiple lens elements. It is well known in the art that lenses may be comprised of multiple lens elements to achieve a particular optical performance.
The Array of Programmable Mirrors 113 is responsible for steering optical signals. However, other beam steering devices, such as a liquid crystal or the like, may also be employed. Cassarly et-al teach one such liquid crystal beam steering device in U.S. Pat. No. 5,107,357, which is fully incorporated by reference herein. It will be clear to one skilled in the art that beam steering devices may be used in any of the described embodiments. In addition, whichever means is employed for steering the optical signals may also steer the optical signals in more than one axis. This permits, among other things, the steering of optical signals from one port to another port without directing the optical signal to a third port. This allows one port in the system to be steered to another port without interfering with any other ports that might be in use at the time.
A prism may optionally be used in any embodiment of the system. Temperature changes cause grating to expand and contract. As gratings expand and contract the wavelength-sized gradations that cause diffraction increase and decrease causing a change in the diffraction angle from a grating. As the temperature changes, the refractive index of the prism changes, which in turn, changes the dispersion of the prism. Accordingly, a prism may be used to balance the thermal affects on Grating 109 . When the prism and Grating 109 are properly designed and configured the effects of temperature on the system are greatly reduced. However, some embodiments of the system do not contain a prism.
Quarter-wave plate (QWP) 107 may also be employed between the Rotationally Symmetric Lens 111 and grating 109 to reduce polarization dependent loss (PDL) in the system. The QWP 107 oriented at 45 deg to the grating lines rotates the polarization so that light that is s-polarized at the grating on the first pass is p-polarized on the second pass and there is no net polarization dependent loss (PDL) for light traveling between the Input Fiber 101 and any of the Output Fibers ( 101 - a through 101 - b ).
A multi-channel light signal 115 enters the device through the Input Fiber 101 , and is directed through one of the Cylindrical Lenses on the Cylindrical Lens Array 103 . The Cylindrical Lens on the Cylindrical Lens Array 103 collimates the multi-channel light signal 115 in the x-axis and directs it through the Anamorphic Lens 105 . When beam size is large, the geometrical limit holds and all the rays are parallel in a collimated beam. As the beam size decreases, diffraction becomes important and it is preferable to locate the beam waist at the Grating. The Anamorphic Lens 105 collimates and focuses the multi-channel light signal 115 in the y-axis and directs it through QWP 107 , and onto Grating 109 . The cylindrical and anamorphic lenses produce a beam with an elliptical footprint on the grating. The major axis of the ellipse is perpendicular to the grooves so that the spectral resolution is maximized, while the overall size of the grating is less than that if a conventional rotationally symmetric collimating lens were used.
The Grating 109 diffracts the individual Channels 117 and 119 of the multi-channel light signal 115 (hereafter channels) towards the Rotationally Symmetric Lens 111 . The Rotationally Symmetric Lens 111 is preferably telecentric, so that the central ray, or chief ray, of each channel is parallel at the MEMS plane. This minimizes the tilt required by the MEMS mirrors. In a telecentric lens, the aperture stop is located at the front focus of the lens, resulting in the exit pupil being at infinity. The Rotationally Symmetric Lens 111 focuses the Channels 117 and 119 , near the Programmable Mirror on the Mirror Array 113 . More specifically, Rotationally Symmetric Lens 111 focuses Channel 117 near the Programmable Mirror associated with Channel 117 , and focuses channel 119 near the Programmable Mirror associated with channel 119 . By focusing the channels in two axes the optical beam size is reduced and the size of the Programmable Mirrors 117 and 119 and Mirror Array 113 may be reduced.
Depending upon the programmed state of the Programmable Mirrors, each channel may be switched to any one of the two of Output Fibers 101 - a or 101 - b . In this regard, each the channel is reflected back through the Rotationally Symmetric Lens 111 which collimates the channels toward Grating 109 . Grating 109 multiplexes the channels switched to the same output fiber and diffracts the resulting beam toward that output fiber. In the presently detailed case of FIG. 1 , the Programmable Mirrors are programmed so as to switch Channel 117 to Output Fiber 101 - a and Channel 119 to Output Fiber 101 - b . Therefore, Channel 117 is reflected from its Programmable Mirror through Rotationally Symmetric Lens 111 which collimates the Channel towards Grating 109 . Grating 109 diffracts Channel 117 through QWP 107 and Anamorphic Lens 105 . Anamorphic Lens 105 focuses Channel 117 in the y-axis toward Cylindrical Lens 103 , which focuses Channel 117 in the x-axis and into Output Fiber 101 - a . Similarly, Channel 119 is reflected from its Programmable Mirror through Rotationally Symmetric Lens 111 which collimates the Channel towards Grating 109 . Grating 109 diffracts Channel 119 through QWP 107 and Anamorphic Lens 105 . Anamorphic Lens 105 focuses Channel 119 in the y-axis toward Cylindrical Lens 103 , which focuses Channel 119 in the x-axis and into Output Fiber 101 - b.
The optical configuration is such that the optical signals directed to and entering Output Fibers 101 - a and 101 b enter the Output Fibers within the cone of acceptance thereby reducing system loss. It will be clear to one skilled in the art that either Channel 117 or Channel 119 may be switched to either Output Fiber 101 - a or 101 - b by simply changing the angle of reflection of the associated Programmable Mirror. In this regard, the system may be scaled to accommodate both a large number of Output Fibers, but also a large number of channels.
It will be clear to one skilled in the art that the system may be operated in the opposite direction. For example, receiving an optical Channel 117 via Port 101 - a , multiplexing it with one or more received optical channels, and directing the multiplexed optical signal via Port 101 .
Turning next to FIG. 2(A) , FIG. 2(B) , and FIG. 2(C) . FIG. 2(A) , FIG. 2(B) , and FIG. 2(C) detail different views of the same device. This embodiment operates similarly to the embodiment detailed FIG. 1(A) , FIG. 1(B) , and FIG. 1(C) above; however, it further employs one or more polarization converters. The operation of a polarization converter is well known in the art. Ducellier teaches one such polarization converter in U.S. Pat. No. 6,411,409, which is fully incorporated by reference herein. As explained, a birefringent crystal beam displacer is oriented in such a way as to separate the input light into two sub-beams with s-polarizations and p-polarizations. A half-wave plate (HWP) covers the p-polarized sub-beam to convert it to s-polarization. Thus, the light leaves the polarization converter with a larger beam, but it is entirely in the s-polarization, which has the highest diffraction efficiency at the high frequency gratings. The birefringent crystal beam displacer preferably uses a uniaxial birefringent crystals such as calcite (CaCO3), yrttrium orthovandate (YV04) or rutile (TiO2) to separate the beams. Another common polarization converter uses a polarization beam splitter and a waveplate. The waveplate is usually a single half-wave plate oriented at 45 degrees with respect to the groove axis positioned in the path of one of the two sub-beams.
The embodiment of present invention detailed in FIG. 2(A) , FIG. 2(B) , and FIG. 2(C) employs one or more polarization converters. Polarization Converter 201 is positioned in the optical path between Input Fiber 101 and the Diffraction Grating 109 and converts multi-channel light signal 115 to entirely s-polarized light. Accordingly, when the larger beam width and entirely s-polarized multi-channel light signal 115 , illuminates Grating 109 , it does so at the highest diffraction efficiency.
Optional Polarization Converter 203 , operated in the opposite direction as Polarization Converter 201 , is positioned in the optical path between Diffraction Grating 109 and the Array of Programmable Mirrors 113 . Polarization Converter 203 re-converts the entirely s-polarized light back to both p-polarized and s-polarized light. Additionally, the size of the combined p-polarized and s-polarized beam leaving the polarization converter is smaller than that of the entirely s-polarized sub-beam entering the converter. This reduces the footprint of the beam at the MEMS mirrors and which enables the use of a smaller size of the MEMS mirror without incurring additional insertion losses. It will be clear to one skilled in the art that there are many ways to ensure that the grating efficiency is maximized by illuminating only with s-polarized light.
A two channel grating-based optical switch, employing one embodiment of the invention, is detailed in FIG. 3(A) , FIG. 3(B) , and FIG. 3(C) . FIG. 3(A) , FIG. 3(B) , and FIG. 3(C) detail different views of the same device. It is of note that while only two channels are used in this example, a substantially larger number of channels and optical ports may be employed. This embodiment allows for demultiplexing, multiplexing and switching separate optical channels to any one of a plurality of optical ports. This embodiment may be dynamically programmed to demultiplex, multiplex and switch any combination of wavelengths to any of a plurality of optical ports.
A Littrow grating is a grating that operates at or near Littrow. Littrow is a special, but common case, in which the angle of incidence of the light on the grating is equal to the angle of diffraction] for which the grating equation becomes:
ml= 2 d sin( a )
where a is the incident angle (same as the diffracted angle), m is the grating order, I is the wavelength, and d is the grating groove spacing. For a reflection grating, rays diffract off the grating back toward the direction from which they originated. In one embodiment, the grating is used near the Littrow condition. Further, using the gratings near the Littrow condition takes advantage of the high diffraction efficiency near the Littrow condition.
The embodiment of the wavelength selective optical switch, detailed in FIG. 3(A) , FIG. 3(B) , and FIG. 3(C) , comprises a Cylindrical Lens Array 303 optically coupled to an Input Fiber 301 , an Anamorphic Lens 305 , a Polarization Beam Splitter (PBS) 307 , Littrow Gratings 311 and 313 , QWP 315 , QWP 317 , QWP 319 , a Rotationally Symmetric Lens 321 , a Array of Programmable Mirrors 323 , a first Output Fiber 301 - a , and a second Output Fiber 301 - b . The device of FIG. 3 may be mounted within an enclosure optimized for optical transmission, including a gas-filled enclosure, or the like. The cylindrical and anamorphic lenses produce a beam with an elliptical footprint on the grating. The major axis of the ellipse is perpendicular to the grooves so that the spectral resolution is maximized, while the overall size of the grating is less than that if a conventional rotationally symmetric collimating lens were used.
Anamorphic Lens 305 and Rotationally Symmetric Lens 311 may be comprised of multiple lens elements. It is well known in the art that lenses may be comprised of multiple lens elements to achieve a particular optical performance.
A prism may optionally be used in any embodiment of the system. Temperature changes cause grating to expand and contract. As gratings expand and contract the wavelength-sized gradations that cause diffraction increase and decrease causing a change in the diffraction angle from a grating. As the temperature changes, the refractive index of the prism changes, which in turn, changes the dispersion of the prism. Accordingly, a prism may be used to balance the thermal affects on Gratings 311 and 313 . When the prism and Gratings 311 and 313 are properly designed and configured the effects of temperature on the system are greatly reduced. However, some embodiments of the system do not contain a prism.
QWP 319 may also be employed to reduce polarization dependent loss (PDL) in the system. QWP 319 oriented at 45 degrees to the grating lines rotates the polarization of light, so that light that is s-polarized at the grating on the first pass is p-polarized on the second pass. The net result is no polarization dependent loss (PDL) for light traveling between the Input Fiber 301 and any of the Output Fibers 301 - a and 301 - b.
A multi-channel light signal 315 enters the device through the Input Fiber 301 , and is directed through one of the Cylindrical Lenses on the Cylindrical Lens Array 303 . The Cylindrical Lens on the Cylindrical Lens Array 303 collimates the multi-channel light signal 315 in the x-axis and directs it through the Anamorphic Lens 305 . When beam size is large, the geometrical limit holds and all the rays are parallel in a collimated beam. As the beam size decreases, diffraction becomes important and it is preferable to locate the beam waist at the Grating. The Anamorphic Lens 305 collimates and focuses the multi-channel light signal 315 in the y-axis and directs into the PBS 307 . The PBS separates multi-channel light signal 315 into its s-polarized and p-polarized states.
Turning briefly to FIG. 4 ., the polarization states of multi-channel light signal 315 are described in detail. Multi-channel light signal 325 enters the PBS 307 and strikes upon the Beam Splitting Surface 309 . The s-polarized optical component reflects off of Beam Splitting Surface 309 and exits the PBS 307 . This s-polarized optical component 325 -S passes through QWP 315 , which converts the polarization state to right-circular 325-RC, and illuminates Littrow Grating 313 . Littrow Grating 313 diffracts the individual channels of light (now left-circular polarized after diffracting of Littrow Grating 313 ) back through QWP 315 which converts their polarization to a p-polarized state 325 -P, and into the PBS 309 . Because these individual channels are now p-polarized they transmit through Beam Splitting Surface 309 and exit the PBS 307 , passing though QWP 319 that converts the polarization states from p-polarized to left-circular 325-LC.
In much the same fashion as described above with the s-polarized optical component, the p-polarized optical component transmits through Beam Splitting Surface 309 , exits PBS 307 , and passes though QWP 317 which converts the polarization state from p-polarized to left-circular, and illuminates Littrow Grating 311 . Littrow Grating 311 diffracts the individual channels of light (now right-circular polarized) back through QWP 317 that converts their polarization to an s-polarized state, and into the PBS 309 . The s-polarized optical component reflects off of Beam Splitting Surface 309 and exits the PBS 307 passing though QWP 319 that converts the polarization states from s-polarized to right-circular 325-RC.
Turning again to FIG. 3(A) , FIG. 3(B) , and FIG. 3(C) , Grating 313 and 311 diffracts the individual Channels 327 and 329 of the multi-channel light signal 325 (hereafter channels) through the PBS 307 and towards the Rotationally Symmetric Lens 321 . The Rotationally Symmetric Lens 321 is preferably telecentric, so that the central ray, or chief ray, of each channel is parallel at the MEMS plane. This minimizes the tilt required by the MEMS mirrors. In a telecentric lens, the aperture stop is located at the front focus of the lens, resulting in the exit pupil being at infinity. The Rotationally Symmetric Lens 321 focuses Channels 317 and 319 in both the x-axis and z-axis, near the Programmable Mirror on the Mirror Array 313 . More specifically, Rotationally Symmetric Lens 321 focuses Channel 327 near the Programmable Mirror associated with Channel 327 , and focuses channel 329 near the Programmable Mirror associated with channel 329 . By focusing the channels in both the x-axis and z-axis, the optical beam size is reduced.
Depending upon the programmed state of the Programmable Mirrors, each channel may be switched to any one of the two of Output Fibers 301 - a or 301 - b . In this regard, each the channel is reflected back through the Rotationally Symmetric Lens 321 which collimates the channels in both the x-axis and z-axis and directs the channels through PBS 307 and onto Gratings 311 and 313 . Gratings 311 and 313 multiplex the channels switched to the same output fiber and diffracts the resulting beam toward that output fiber. In the presently detailed case of FIG. 3 , the Programmable Mirrors are programmed so as to switch Channel 327 to Output Fiber 301 - a and Channel 329 to Output Fiber 301 - b.
The optical configuration is such that the optical signals directed to and entering Output Fibers 301 - a and 301 b enter the Output Fibers within the cone of acceptance thereby reducing system loss. It will be clear to one skilled in the art that either Channel 317 or Channel 319 may be switched to either Output Fiber 301 - a or 301 - b by simply changing the angle of reflection of the associated Programmable Mirror. In this regard, the system may be scaled to accommodate both a large number of Output Fibers, but also a large number of channels.
It will be clear to one skilled in the art that the system may be operated in the opposite direction. For example, by receiving an optical Channel 327 via Port 301 - a , multiplexing it with one or more received optical channels, and directing the multiplexed optical signal via Port 301 .
A two channel grating-based optical switch, employing one embodiment of the invention, is detailed in FIG. 5(A) , FIG. 5(B) , and FIG. 5(C) . FIG. 5(A) , FIG. 5(B) , and FIG. 5(C) detail different views of the same device. It is of note that while only two channels are used in this example, a substantially larger number of channels and optical ports may be employed. The wavelength selective optical switch allows for demultiplexing, switching separate optical channels, and multiplexing to any one of a plurality of optical ports. The wavelength selective optical switch of FIG. 5 may be dynamically programmed to demultiplex, multiplex and switch any combination of wavelengths to any of a plurality of optical ports.
The embodiment of the wavelength selective optical switch device of FIG. 5(A) , FIG. 5(B) , and FIG. 5(C) comprises a Cylindrical Lens Array 503 optically coupled to an Input Fiber 501 , an Anamorphic Lens 505 , a transmissive Grating 513 operating near Littrow, a Rotationally Symmetric Lens 521 , a Array of Programmable Mirrors 523 , a first Output Fiber 501 - a , and a second Output Fiber 501 - b . The device of FIG. 5 may be mounted within an enclosure optimized for optical transmission, including a gas-filled enclosure, or the like. The cylindrical and anamorphic lenses produce a beam with an elliptical footprint on the grating. The major axis of the ellipse is perpendicular to the grooves so that the spectral resolution is maximized, while the overall size of the grating is less than that if a conventional rotationally symmetric collimating lens were used.
Anamorphic Lens 505 and Rotationally Symmetric Lens 521 may be comprised of multiple lens elements. It is well known in the art that lenses may be comprised of multiple lens elements to achieve a particular optical prescription.
A prism may optionally be used in any embodiment of the system. Temperature changes cause grating to expand and contract. As gratings expand and contract the wavelength-sized gradations that cause diffraction increase and decrease causing a change in the diffraction angle from a grating. As the temperature changes, the refractive index of the prism changes, which in turn, changes the dispersion of the prism. Accordingly, a prism may be used to balance the thermal affects on Grating 513 . When the prism and Grating 513 are properly designed and configured the effects of temperature on the system are greatly reduced. However, some embodiments of the system do not contain a prism.
The embodiment of present invention detailed in FIG. 5(A) , FIG. 5(B) , and FIG. 5(C) employs one or more polarization converters. Polarization Converter 502 is positioned in the optical path between Input Fiber 501 and the Grating 513 and converts multi-channel light signal 525 to entirely s-polarized light. Accordingly, when the larger beam width and entirely s-polarized multi-channel light signal 525 , illuminates Grating 513 , it does so at the highest diffraction efficiency.
Optional Polarization Converter 524 , operated in the opposite direction as Polarization Converter 502 , is positioned in the optical path between Grating 513 and the Array of Programmable Mirrors 523 . Polarization Converter 524 re-converts the entirely s-polarized light back to both p-polarized and s-polarized light. Additionally, the size of the combined p-polarized and s-polarized beam leaving the polarization converter is smaller than that of the entirely s-polarized sub-beam entering the converter. This reduces the footprint of the beam at the MEMS mirrors and which enables the use of a smaller size of the MEMS mirror without incurring additional insertion losses.
A multi-channel light signal 525 enters the device through the Input Fiber 501 , and is directed through one of the Cylindrical Lenses on the Cylindrical Lens Array 503 . The Cylindrical Lens on the Cylindrical Lens Array 503 collimates the multi-channel light signal 525 in the x-axis and directs it through the Anamorphic Lens 505 . When beam size is large, the geometrical limit holds and all the rays are parallel in a collimated beam. As the beam size decreases, diffraction becomes important and it is preferable to locate the beam waist at the Grating. The Anamorphic Lens 505 collimates and focuses the multi-channel light signal 525 in the y-axis and directs it through Grating 513 . The cylindrical and anamorphic lenses produce a beam with an elliptical footprint on the grating. The major axis of the ellipse is perpendicular to the grooves so that the spectral resolution is maximized, while the overall size of the grating is less than that if a conventional rotationally symmetric collimating lens were used.
The Grating 513 diffracts the individual Channels 527 and 529 of the multi-channel light signal 525 (hereafter channels) through QWP 519 and towards the Rotationally Symmetric Lens 521 . The Rotationally Symmetric Lens 521 focuses the Channels 527 and 529 , in both the x-axis and z-axis, near the Programmable Mirror on the Mirror Array 523 . More specifically, Rotationally Symmetric Lens 521 focuses Channel 527 near the Programmable Mirror associated with Channel 527 , and focuses channel 529 near the Programmable Mirror associated with channel 529 . By focusing the channels in both the x-axis and z-axis, the optical beam size is reduced and the size of the Programmable Mirrors and Mirror Array 523 may be reduced. Further, the focal length may be reduced thereby compacting the device.
Depending upon the programmed state of the Programmable Mirrors, each channel may be switched to any one of the two of Output Fibers 501 - a or 501 - b . In this regard, each the channel is reflected back through the Rotationally Symmetric Lens 521 which collimates the channels in both the x-axis and z-axis and directs the channels through Grating 513 . Grating 513 multiplexes the channels switched to the same output fiber and diffracts the resulting beam toward that output fiber. In the presently detailed case of FIG. 5 , the Programmable Mirrors are programmed so as to switch Channel 527 to Output Fiber 501 - a and Channel 529 to Output Fiber 501 - b.
The optical configuration is such that the optical signals directed to and entering Output Fibers 501 - a and 501 b enter the Output Fibers within the cone of acceptance thereby reducing system loss. It will be clear to one skilled in the art that either Channel 527 or Channel 529 may be switched to either Output Fiber 501 - a or 501 - b by simply changing the angle of reflection of the associated Programmable Mirror. In this regard, the system may be scaled to accommodate both a large number of Output Fibers, but also a large number of channels.
It will be clear to one skilled in the art that the system may be operated in the opposite direction. For example, by receiving an optical Channel 527 via Port 501 - a , multiplexing it with one or more received optical channels, and directing the multiplexed optical signal via Port 501 .
A seventeen port grating-based optical switch for sixty four 100 GHz spaced channels, employing one embodiment of the invention, is detailed in FIG. 6(A) , FIG. 6(B) , and FIG. 6(C) . FIG. 6(A) , FIG. 6(B) , and FIG. 6(C) detail different views of the same device. For clarity, in FIG. 6(A) , FIG. 6(B) , and FIG. 6(C) , only the center and extreme ports, and 2 optical channels, are depicted. The wavelength selective optical switch allows for demultiplexing, switching separate optical channels, and multiplexing to any one of a plurality of optical ports. The wavelength selective optical switch of FIG. 6 may be dynamically programmed to demultiplex, switch, and multiplex any combination of channels to any of a plurality of optical ports.
The embodiment of the wavelength selective optical switch device of FIG. 6(A) , FIG. 6(B) , and FIG. 6(C) comprises a Cylindrical Lens Array 603 optically coupled to an Input Fiber 601 , a Cylindrical Lens 605 , a prism 607 , a transmission Grating 609 operating near Littrow, a Rotationally Symmetric Lens 611 , an Array of Programmable Mirrors 613 , a first Output Fiber 601 - a , and a second Output Fiber 601 - b . The device of FIG. 6 may be mounted within an enclosure optimized for optical transmission, including a gas-filled enclosure, or the like. The cylindrical and anamorphic lenses produce a beam with an elliptical footprint on the grating. The major axis of the ellipse is perpendicular to the grooves so that the spectral resolution is maximized, while the overall size of the grating is less than that if a conventional rotationally symmetric collimating lens were used.
Cylindrical Lens 605 and Rotationally Symmetric Lens 611 are both comprised of multiple lens elements. It is well known in the art that lenses may be comprised of multiple lens elements to reduce the lens aberrations over a large range of frequencies (6.4 THz), operating temperatures (−20° C. to 70° C.), and field of view. Cylindrical Lens 605 and Rotationally Symmetric Lens 611 have numeric apertures of 0.2 and 0.235, respectively. Table 1 lists the optical prescription for the wavelength selective optical switch in CODE V format.
TABLE 1
Optical Prescription for seventeen port grating-based optical switch
OBJ:
RDY
THI
RMD
GLA
INFINITY
3.146570
1:
INFINITY
0.450000
SILICON_SPECIAL
2:
INFINITY
0.000000
RDX:
−8.10984
Lens spacing:
1.3347E+00
A:
1.2682E−03
3:
INFINITY
0.453430
AIR
4:
−3.30747
2.919365
SF11_SCHOTT
CYL:
RDX:
INFINITY
5:
−3.74895
11.188256
AIR
CYL:
RDX:
INFINITY
6:
−39.82847
2.000000
SF15_SCHOTT
CYL:
RDX:
INFINITY
7:
8.25289
3.069427
NBAK1_SCHOTT
CYL:
RDX:
INFINITY
8:
−7.03286
0.214935
AIR
CYL:
RDX:
INFINITY
9:
−6.44129
2.000000
NBK10_SCHOTT
CYL:
RDX:
INFINITY
10:
9.62630
2.938672
NSK2_SCHOTT
CYL:
RDX:
INFINITY
11:
−15.90151
0.328897
AIR
CYL:
RDX:
INFINITY
12:
INFINITY
3.000000
SF14_SCHOTT
SLB:
“prism”
13:
INFINITY
3.000000
AIR
XDE:
0.000000
YDE:
0.000000
ZDE:
0.000000
ADE:
15.219671
BDE:
0.000000
CDE:
0.000000
14:
INFINITY
0.000000
AIR
XDE:
0.000000
YDE:
0.000000
ZDE:
0.000000
ADE:
0.1e21
BDE:
0.000000
CDE:
0.000000
15:
INFINITY
0.000000
AIR
XDE:
0.000000
YDE:
−2.190327
ZDE:
17.000000
GLB
G12
ADE:
−76.238409
BDE:
0.000000
CDE:
0.000000
16:
INFINITY
2.000000
SILICA_SPECIAL
STO:
INFINITY
2.000000
SILICA_SPECIAL
SLB:
“grt”
GL2:
AIR
GRT:
GRO:
−1.000000
GRS:
0.000909
GRX:
0.000000
GRY:
1.000000
GRZ:
0.000000
18:
INFINITY
2.000000
AIR
19:
INFINITY
10.626347
AIR
XDE:
0.000000
YDE:
−3.824794
ZDE:
0.000000
ADE:
−56.872509
BDE:
0.000000
CDE:
0.000000
20:
40.02527
5.798156
NLASF31_SCHOTT
SLB:
“foc”
21:
−510.83375
5.947632
NLAK10_SCHOTT
22:
127.58156
1.702233
AIR
23:
19.84076
4.276553
NSF1_SCHOTT
24:
25.60107
4.125666
SF1_SCHOTT
25:
12.99810
11.900816
AIR
26:
−21.31335
2.894729
NLAK10_SCHOTT
27:
68.54462
12.995558
NLASF31_SCHOTT
28:
−31.91252
6.790847
AIR
29:
43.81835
12.994567
SF57_SCHOTT
30:
−47.90572
12.994310
SFL57_SCHOTT
31:
138.80596
5.065914
AIR
32:
INFINITY
0.000000
XDE:
0.000000
YDE:
0.000000
ZDE:
0.000000
DAR
ADE:
0.371634
BDE:
0.000000
CDE:
0.000000
IMG:
INFINITY
0.000000
The embodiment of present invention detailed in FIG. 6(A) , FIG. 6(B) , and FIG. 6(C) employs a Volume Holographic Grating 609 with 1100 grooves/mm made on a substrate with low coefficient of thermal expansion, such as fused silica. Because this grating has poor efficiency in the p-polarization, the s- and p-polarization are split (not shown) and the s-polarization is switched by the optics shown in FIG. 6(A) , FIG. 6(B) , and FIG. 6(C) . The p-polarization is rotated by 90°, so that it is s-polarized, and sent through a set of optics that are identical to the s-polarized optics. This technique of splitting the two polarizations and running each through an identical set of optics is known as polarization diversity.
Prism 607 is employed to compensate for changes in the grating groove spacing with temperature. As gratings expand and contract the wavelength-sized gradations that cause diffraction increase and decrease causing a change in the diffraction angle from a grating. As the temperature changes, the refractive index of the prism changes, which in turn, changes the dispersion of the prism. Accordingly, prism 607 is used to balance the thermal affects on Grating 609 . When Prism 607 and Grating 609 are properly designed and configured the effects of temperature on the system are greatly reduced. Prism 607 is preferable made of a glass with a large change in the optical path length with temperature, such as SF14 by Schott, to minimize the prismatic power required.
A multi-channel light signal 615 enters the device through the Input Fiber 601 , and is directed through one of the Cylindrical Lenses on the Cylindrical Lens Array 603 . The Cylindrical Lens on the Cylindrical Lens Array 603 collimates the multi-channel light signal 615 in the x-axis and directs it through the Anamorphic Lens 605 . When beam size is large, the geometrical limit holds and all the rays are parallel in a collimated beam. As the beam size decreases, diffraction becomes important and it is preferable to locate the beam waist at the Grating. The Cylindrical Lens 605 collimates and focuses the multi-channel light signal 615 in the y-axis and directs it through Grating 609 .
The Grating 609 diffracts the individual Channels 617 and 619 (hereafter channels) of the multi-channel light signal 615 towards the Rotationally Symmetric Lens 611 . The Rotationally Symmetric Lens 611 focuses the Channels 617 and 619 , near the Programmable Mirror on the Mirror Array 613 . More specifically, Rotationally Symmetric Lens 611 focuses Channel 617 near the Programmable Mirror associated with Channel 617 , and focuses channel 619 near the Programmable Mirror associated with channel 619 . By focusing the channels, the optical beam size is reduced and the size of the Programmable Mirrors and Mirror Array 613 may be reduced. Further, the focal length may be reduced thereby compacting the device.
Depending upon the programmed state of the Programmable Mirrors, each channel may be switched to any one of the Output Fibers 601 - a or 601 - b . In this regard, each the channel is reflected back through the Rotationally Symmetric Lens 611 which collimates the channels and directs the channels through Grating 609 . Grating 609 multiplexes the channels switched to the same output fiber and diffracts the resulting beam toward that output fiber. In the presently detailed case of FIG. 6 , the Programmable Mirrors are programmed so as to switch Channel 617 to Output Fiber 601 - a and Channel 619 to Output Fiber 601 - b.
The optical configuration is such that the optical signals directed to and entering Output Fibers 601 - a and 601 b enter the Output Fibers within the cone of acceptance thereby reducing system loss. It will be clear to one skilled in the art that either Channel 617 or Channel 619 may be switched to either Output Fiber 601 - a or 601 - b by simply changing the angle of reflection of the associated Programmable Mirror. In this regard, the system supports both a large number of Output Fibers, and a large number of channels.
It will be clear to one skilled in the art that the system may be operated in the opposite direction. For example, by receiving an optical Channel 617 via Port 601 - a , multiplexing it with one or more received optical channels, and directing the multiplexed optical signal via Port 601 .
A two channel grating-based optical switch, employing one embodiment of the invention, is detailed in FIG. 7(A) , FIG. 7(B) , and FIG. 7(C) . FIG. 7(A) , FIG. 7(B) , and FIG. 7(C) detail different views of the same device. It is of note that while only two channels are used in this example, a substantially larger number of channels and optical ports may be employed. This embodiment allows for demultiplexing, multiplexing and switching separate optical channels to any one of a plurality of optical ports. This embodiment may be dynamically programmed to demultiplex, multiplex and switch any combination of wavelengths to any of a plurality of optical ports.
The embodiment of the wavelength selective optical switch, detailed in FIG. 7(A) , FIG. 7(B) , and FIG. 7(C) , comprises a Cylindrical Lens Array 703 optically coupled to an Input Fiber 701 , an Anamorphic Lens 705 , a first Polarization Beam Splitter (PBS) 707 , Half-Waveplate (HWP) 709 , Littrow Gratings 711 and 713 , HWP 715 , a second PBS 717 , QWP 719 , Rotationally Symmetric Lens 721 , a Array of Programmable Mirrors 723 , a first Output Fiber 701 - a , and a second Output Fiber 701 - b . The device of FIG. 7 may be mounted within an enclosure optimized for optical transmission, including a gas-filled enclosure, or the like.
Anamorphic Lens 705 and Rotationally Symmetric Lens 711 may be comprised of multiple lens elements. It is well known in the art that lenses may be comprised of multiple lens elements to achieve a particular optical performance. A prism may optionally be used in any embodiment of the system.
A multi-channel light signal 725 enters the device through the Input Fiber 701 , and is directed through one of the Cylindrical Lenses on the Cylindrical Lens Array 703 . The Cylindrical Lens on the Cylindrical Lens Array 703 collimates the multi-channel light signal 725 in the x-axis and directs it through the Anamorphic Lens 705 . When beam size is large, the geometrical limit holds and all the rays are parallel in a collimated beam. As the beam size decreases, diffraction becomes important and it is preferable to locate the beam waist at the Grating. The Anamorphic Lens 705 collimates and focuses the multi-channel light signal 725 in the y-axis and directs it into the first PBS 707 . The PBS separates multi-channel light signal 725 into its s-polarized and p-polarized states.
The s-polarized optical component of Multi-channel light signal 725 reflects off of the Beam Splitting Surface 708 of PBS 707 and exits PBS 707 . The s-polarized optical component then diffracts through Littrow Grating 713 and passes though HWP 715 which converts the s-polarization state to a p-polarized state. The p-polarized optical component of Multi-channel light signal 725 transmits through the Beam Splitting Surface 708 of PBS 707 , exits PBS 707 , and passes though HWP 709 which converts the p-polarization state from p-polarized to s-polarized. This s-polarized light diffracts through Littrow Grating 711 .
Grating 711 diffracts the individual Channels 727 and 729 (hereafter channels) of the multi-channel light signal 725 into PBS 717 . Grating 713 diffracts the individual channels through HWP 715 which converts the s-polarization state to a p-polarized state.
Both the p-polarized and s-polarized states of the individual channels enter second PBS 717 ; the s-polarized state reflects off of the Beam Splitting Surface 718 of PBS 717 and exits PBS 717 . The p-polarized state transmits through the Beam Splitting Surface 718 of PBS 717 , and exits PBS 717 recombined with the s-polarized state.
The individual channels are directed through QWP 719 and through Rotationally Symmetric Lens 721 . The Rotationally Symmetric Lens 721 focuses Channels 727 and 729 in both the x-axis and y-axis, near the Programmable Mirror on the Mirror Array 723 . More specifically, Rotationally Symmetric Lens 721 focuses Channel 727 near the Programmable Mirror associated with Channel 727 , and focuses channel 729 near the Programmable Mirror associated with channel 729 . By focusing the channels in both the x-axis and y-axis, the optical beam size is reduced.
Depending upon the programmed state of the Programmable Mirrors, each channel may be switched to any one of the two of Output Fibers 701 - a or 701 - b . In this regard, each the channel is reflected back through the device in reverse and is directed toward that appropriate output fiber. In the presently detailed case of FIG. 7 , the Programmable Mirrors are programmed so as to switch Channel 727 to Output Fiber 701 - a and Channel 729 to Output Fiber 701 - b . The optical configuration is such that the optical signals directed to and entering Output Fibers 701 - a and 701 b enter the Output Fibers within the cone of acceptance thereby reducing system loss. It will be clear to one skilled in the art that either Channel 727 or Channel 729 may be switched to either Output Fiber 701 - a or 701 - b by simply changing the angle of reflection of the associated Programmable Mirror. In this regard, the system may be scaled to accommodate both a large number of Output Fibers, but also a large number of channels.
It will be clear to one skilled in the art that the system may be operated in the opposite direction. For example, by receiving an optical Channel 727 via Port 701 - a , multiplexing it with one or more received optical channels, and directing the multiplexed optical signal via Port 701 .
A two channel grating-based optical switch, employing one embodiment of the invention, is detailed in FIG. 8(A) , FIG. 8(B) , FIG. 8(C) , and FIG. 8(D) . FIG. 8(A) , FIG. 8(B) , FIG. 8(C) , and FIG. 8(D) . detail different views of the same device. It is of note that while only two channels are used in this example, a substantially larger number of channels and optical ports may be employed. The wavelength selective optical switch allows for demultiplexing, multiplexing and switching separate optical channels to any one of a plurality of optical ports. The wavelength selective optical switch of FIG. 8 may be dynamically programmed to demultiplex, multiplex and switch any combination of wavelengths to any of a plurality of optical ports.
A first embodiment of the wavelength selective optical switch device of FIG. 8(A) , FIG. 8(B) , FIG. 8(C) , and FIG. 8(D) comprises First Cylindrical Lens Array 803 optically coupled to an Input Fiber 801 , a First Anamorphic Lens 805 , a First Grating 807 , a First Rotationally Symmetric Lens 809 , an Array of programmable Transmissive Beam Steerers (TBS) 810 , a Second Anamorphic Lens 815 , a Second Littrow Grating 817 , a Second Anamorphic Lens 815 , a Second Cylindrical Lens Array 813 , a first Output Fiber 811 - a , and a second Output Fiber 811 - b.
The device of FIG. 8 may be mounted within an enclosure optimized for optical transmission, including a gas-filled enclosure, or the like.
The First and Second Cylindrical Lens Arrays 803 and 813 , First and Second Anamorphic Lenses 805 and 815 , and First and Second Rotationally Symmetric Lenses 809 and 819 may be comprised of multiple lens elements. It is well known in the art that lenses may be comprised of multiple lens elements to achieve a particular optical performance.
The Array of programmable TBS 810 is responsible for steering optical signals. However, other beam steering devices, such as a liquid crystal or the like, may also be employed. It will be clear to one skilled in the art that beam steering devices may be used in any of the described embodiments.
A prism may optionally be used in any embodiment of the system. Temperature changes cause grating to expand and contract. As gratings expand and contract the wavelength-sized gradations that cause diffraction increase and decrease causing a change in the diffraction angle from a grating. As the temperature changes, the refractive index of the prism changes, which in turn, changes the dispersion of the prism. Accordingly, a prism may be used to balance the thermal affects on the First and Second Gratings 807 and 817 . When the prism and gratings are properly designed and configured the effects of temperature on the system are greatly reduced. However, some embodiments of the system do not contain a prism.
A multi-channel light signal 821 enters the device through the Input Fiber 801 , and is directed through one of the Cylindrical Lenses on the First Cylindrical Lens Array 803 . The Cylindrical Lens on the First Cylindrical Lens Array 803 collimates the multi-channel light signal 821 and directs it through the First Anamorphic Lens 805 . When beam size is large, the geometrical limit holds and all the rays are parallel in a collimated beam. As the beam size decreases, diffraction becomes important and it is preferable to locate the beam waist at the Grating. The First Anamorphic Lens 805 collimates and focuses the multi-channel light signal 821 and directs it onto First Grating 807 . The cylindrical and anamorphic lenses produce a beam with an elliptical footprint on the grating. The major axis of the ellipse is perpendicular to the grooves so that the spectral resolution is maximized, while the overall size of the grating is less than that if a conventional rotationally symmetric collimating lens were used.
First Grating 807 diffracts the individual Channels 823 and 825 of the multi-channel light signal 821 (hereafter channels) towards the First Rotationally Symmetric Lens 809 . The First Rotationally Symmetric Lens 809 is preferably telecentric, so that the central ray, or chief ray, of each channel is parallel at the TBS plane. This minimizes the tilt required by the TBS. In a telecentric lens, the aperture stop is located at the front focus of the lens, resulting in the exit pupil being at infinity. The First Rotationally Symmetric Lens 809 focuses the Channels 823 and 825 , in both the x-axis and y-axis, near the TBS Array 810 . More specifically, Rotationally Symmetric Lens 809 focuses Channel 823 near the Programmable Mirror associated with Channel 823 , and focuses channel 825 near the Programmable Mirror associated with channel 825 . By focusing the channels in both the x-axis and y-axis, the optical beam size is reduced and the size of the TBS 810 may be reduced.
Depending upon the programmed state of the TBS 810 , each channel may be switched to any one of the two of Output Fibers 811 - a or 811 - b . In this regard, each the channel is transmitted through the Second Rotationally Symmetric Lens 819 which collimates the channels in both the x-axis and y-axis toward Second Grating 817 . Second Grating 817 multiplexes the channels switched to the same output fiber and diffracts the resulting beam toward that output fiber. In the presently detailed case of FIG. 8 , TBS 810 is programmed so as to switch Channel 823 to Output Fiber 811 - a and Channel 825 to Output Fiber 811 - b . Therefore, Channel 823 is directed by its corresponding beam steerer on TBS 810 through Second Rotationally Symmetric Lens 819 which collimates the Channel towards Second Grating 817 . Second Grating 817 diffracts Channel 823 through Second Anamorphic Lens 815 . Second Anamorphic Lens 815 focuses Channel 823 toward Second Cylindrical Lens 803 , which focuses Channel 823 into Output Fiber 811 - a . Similarly, Channel 825 is transmitted through Second Rotationally Symmetric Lens 819 which collimates the Channel towards Second Grating 817 . Second Grating 817 diffracts Channel 825 through Second Anamorphic Lens 815 . Second Anamorphic Lens 815 focuses Channel 825 toward Second Cylindrical Lens 813 , which focuses Channel 825 into Output Fiber 811 - b.
The optical configuration is such that the optical signals directed to and entering Output Fibers 811 - a and 811 b enter the Output Fibers within the cone of acceptance thereby reducing system loss. It will be clear to one skilled in the art that either Channel 823 or Channel 825 may be switched to either Output Fiber 811 - a or 811 - b by simply changing the angle of direction of the associated TBS. In this regard, the system may be scaled to accommodate both a large number of Output Fibers, but also a large number of channels.
It will be clear to one skilled in the art that the system may be operated in the opposite direction. For example, receiving an optical Channel 813 via Port 811 - a , multiplexing it with one or more received optical channels, and directing the multiplexed optical signal via Port 801 - a or 801 - b.
A two channel grating-based optical switch, employing one embodiment of the invention, is detailed in FIG. 9(A) , FIG. 9(B) , FIG. 9(C) , and FIG. 9D ). FIG. (A), FIG. 9(B) , FIG. 9(C) , and FIG. 9(D) detail different views of the same device. It is of note that while only two channels are used in this example, a substantially larger number of channels and optical ports may be employed. This embodiment allows for demultiplexing, multiplexing and switching separate optical channels to any one of a plurality of optical ports. This embodiment may be dynamically programmed to demultiplex, multiplex and switch any combination of wavelengths to any of a plurality of optical ports.
The embodiment of the wavelength selective optical switch, detailed in FIG. (A), FIG. 9(B) , FIG. 9(C) , and FIG. 9(D) , comprises a Cylindrical Lens Array 903 optically coupled to an Input Fiber 901 , an Anamorphic Lens 905 , a Polarization Beam Splitter (PBS) 907 , Littrow Gratings 911 and 915 , Faraday Rotators 909 and 913 , QWP 916 , Rotationally Symmetric Lens 917 , a Array of Programmable Mirrors 923 , a first Output Fiber 901 - a , and a second Output Fiber 901 - b . The device of FIG. 9 may be mounted within an enclosure optimized for optical transmission, including a gas-filled enclosure, or the like. The cylindrical and anamorphic lenses produce a beam with an elliptical footprint on the grating. The major axis of the ellipse is perpendicular to the grooves so that the spectral resolution is maximized, while the overall size of the grating is less than that if a conventional rotationally symmetric collimating lens were used.
Anamorphic Lens 905 and Rotationally Symmetric Lens 917 may be comprised of multiple lens elements. It is well known in the art that lenses may be comprised of multiple lens elements to achieve a particular optical performance.
A prism may optionally be used in any embodiment of the system. Temperature changes cause grating to expand and contract. As gratings expand and contract the wavelength-sized gradations that cause diffraction increase and decrease causing a change in the diffraction angle from a grating. As the temperature changes, the refractive index of the prism changes, which in turn, changes the dispersion of the prism. Accordingly, a prism may be used to balance the thermal affects on Gratings 911 and 915 . Littrow Grating 911 and 915 may be optically coupled to one of the prism's surface. When the prism and Gratings 911 and 915 are properly designed and configured the effects of temperature on the system are greatly reduced. However, some embodiments of the system do not contain a prism.
QWP 916 may also be employed to reduce polarization dependent loss (PDL) in the system. QWP 916 oriented at 45 deg to the grating lines rotates the polarization of light traveling through the QWP so that light that is s-polarized at the grating on the first pass is p-polarized on the second pass. The net result is no polarization dependent loss (PDL) for light traveling between the Input Fiber 901 and any of the Output Fibers 901 - a and 901 - b.
A multi-channel light signal 925 enters the device through the Input Fiber 901 , and is directed through one of the Cylindrical Lenses on the Cylindrical Lens Array 903 . The Cylindrical Lens on the Cylindrical Lens Array 903 collimates the multi-channel light signal 915 in the z-axis and directs it through the Anamorphic Lens 905 . When beam size is large, the geometrical limit holds and all the rays are parallel in a collimated beam. As the beam size decreases, diffraction becomes important and it is preferable to locate the beam waist at the Grating. The Anamorphic Lens 905 collimates and focuses the multi-channel light signal 915 in the y-axis and directs it into the PBS 907 . The PBS separates multi-channel light signal 925 into its s-polarized and p-polarized states.
Turning briefly to FIG. 10 , the polarization states of multi-channel light signal 925 are described in detail. Multi-channel light signal 925 strikes PBS 907 and the s-polarized optical component reflects, while the p-polarized component transmits through PBS 907 . The s-polarized component of Multi-channel light signal 925 striking PBS 907 is not parallel to the y-axis, because the micro cylindrical collimators array 901 , 901 - a , and 901 - b are not in the xy-plane. The s-polarized optical component 925 -SB passes through Faraday Rotator (FR) 909 , which rotates the polarization state by 45 degrees such that the light 925 -SG is s-polarized at the Littrow Grating 911 . A Faraday rotator is a non-reciprocal optical device that rotates the polarization plane of both forward and backward transmitted beam in a certain direction, regardless of the transmission direction of the beam. Littrow Grating 911 diffracts the individual channels 919 -SG and 921 -SG of light back through FR 909 that rotates the light a further 45 degrees so that the light 919 -PB and 921 -PB is p-polarized in the reference frame of PBS 907 . Because individual channels 919 -PB and 921 -PB are now p-polarized they transmit through PBS surface 907 and exit the PBS 907 , passing though QWP 916 that converts the p-polarized light to left circularly polarized light 919 -LC and 921 -LC.
Preferably, the input beam 925 at the PBS 907 , and diffraction gratings 911 and 915 are oriented such that the s-p coordinates at the grating are rotated by 45 degrees from the s-p coordinates at the gratings. For example, in one embodiment, the incident beam makes a 51 degree angle with the y-axis and is in the y-z plane and the PBS is rotated by 38 degrees around the y-axis by 38 degrees. One skilled in the art will recognize that many orientations of the incident beams 925 , PBS, and diffraction grating are possible.
In much the same fashion as described above with the s-polarized optical component, the p-polarized optical component 925 -PB transmits through PBS 907 and passes though FR 913 which rotates the polarization state from p-polarized in the reference frame of the PBS to s-polarized in the reference frame of the grating, and illuminates Littrow Grating 911 . Littrow Grating 911 diffracts the individual channels of light back through FR 913 that converts their polarization to an s-polarized state in the reference frame of PBS 907 , and into PBS 909 . The s-polarized optical component 919 -SB and 921 -SB reflects off of PBS 907 , passing though QWP 916 that converts the s-polarized light to right circularly polarized light 919 -RC and 921 -RC
Turning again to FIG. 9(A) , FIG. 9(B) , FIG. 9(C) , and FIG. 9(D) , Gratings 911 and 915 diffracts the individual Channels 919 and 921 of the multi-channel light signal 925 (hereafter channels) through PBS 907 , QWP 916 , and towards Rotationally Symmetric Lens 917 . The Rotationally Symmetric Lens 917 is preferably telecentric, so that the central ray, or chief ray, of each channel is parallel at the mirrors plane. This minimizes the tilt required by the MEMS mirrors. In a telecentric lens, the aperture stop is located at the front focus of the lens, resulting in the exit pupil being at infinity. The Rotationally Symmetric Lens 917 focuses Channels 919 and 921 in both the x-axis and y′-axis (not shown), near the Programmable Mirror on the Mirror Array 923 . More specifically, Rotationally Symmetric Lens 917 focuses Channel 919 near the Programmable Mirror associated with Channel 919 , and focuses channel 921 near the Programmable Mirror associated with channel 921 . By focusing the channels in both the x-axis and y′-axis (not shown), the optical beam size is reduced.
Depending upon the programmed state of the Programmable Mirrors, each channel may be switched to any one of the two of Output Fibers 901 - a or 901 - b . In this regard, each the channel is reflected back through the Rotationally Symmetric Lens 917 which collimates the channels in both the x-axis and y′-axis (not shown) and directs the channels through PBS 907 and onto Gratings 911 and 913 . Gratings 911 and 913 multiplex the channels switched to the same output fiber and diffracts the resulting beam toward that output fiber. In the presently detailed case of FIG. 9 , the Programmable Mirrors are programmed so as to switch Channel 919 to Output Fiber 901 - a and Channel 921 to Output Fiber 901 - b.
The optical configuration is such that the optical signals directed to and entering Output Fibers 901 - a and 901 - b enter the Output Fibers within the cone of acceptance thereby reducing system loss. It will be clear to one skilled in the art that either Channel 919 or Channel 921 may be switched to either Output Fiber 901 - a or 901 - b by simply changing the angle of reflection of the associated Programmable Mirror. In this regard, the system may be scaled to accommodate both a large number of Output Fibers, but also a large number of channels.
It will be clear to one skilled in the art that the system may be operated in the opposite direction. For example, by receiving an optical Channel 927 via Port 901 - a , multiplexing it with one or more received optical channels, and directing the multiplexed optical signal via Port 901 . | A wavelength selective optical switch particularly usable as a programmable N×M optical switch in a multi-wavelength communication system. The switch uses a grating that separates multi-channel optical signals into a plurality of optical channels, and combines a plurality of optical channels into multi-channel optical signals. Programmable mirrors switch each optical channel to any of a plurality of fibers coupled to the switch. | 6 |
This application is a continuation of application Ser. No. 08/100,277 filed Aug. 2, 1993, now abandoned.
BACKGROUND
During many sewing operations in the garment industry, it is desirable to quickly load, hold together, and sew together two pieces of fabric material. Sometimes it is also desirable to fold one of the fabric work pieces during loading or at some other time before the work pieces are sewn together.
Some automatic sewing machines are restricted to sewing a linear seam. Other automatic sewing machines have complicated clamping mechanisms moving on X-Y tables. Some machines move the work pieces in an X-Y pattern while the stationary sewing heads sew rectilinear seams. Yet other machines have a sewing head traverse one axis while the holding apparatus moves the workpieces on one or two axis.
Existing pocket setting automatic sewing machines slide positioned fabric work pieces over a fixed table having a polished surface. Work pieces are pressed against the polished surface by work piece holders. The work piece holders cause the work pieces to move into the sewing station from the loading and folding locations. Movement of the work piece holders during the sewing operation creates the seam outline. However, the sliding action of the work pieces over the polished table surface sometimes cause the work piece materials to bunch.
The fastest machine cycle times are achieved by dedicated automatic pocket setting sewing machines, limited to a specific task. These machines have two workpiece holders, each of which is mounted on a cumbersome and expensive guiding system. Only by having two workpiece holders can the machine operator load subsequent workpieces while a previously loaded workpiece is being sewn.
Moreover, when sewing pockets on polo type shirts, current machines require the shirts to be open at the shoulders for the sewing operation to be accomplished. In the garment industry, some types of shirts are sold with and without pockets. In order to minimize warehousing and inventory costs, it is desirable to warehouse these types of shirts without a pocket. After an order is received, pockets could be quickly sewn on the pocketless shirts if the order required. Moreover, pocket placement could be more accurate because it would be the last operation. However, no known machine sews pockets on already finished shirts.
Many small factories in the garment industry do not have skilled repairmen on staff, making it important that sewing machines be simple and require minimum maintenance. Additionally these small factories lack the capital to invest in high cost single purpose dedicated machines and prefer more flexible machines that can be utilized for other purposes.
With the foregoing in mind, it is the object of this invention to produce an automatic pocket setting sewing machine in which the loading and folding operations can be accomplished during the sewing operation thus allowing for minimum machine cycle times.
Yet another object of the present invention is to eliminate workpiece holders and their complicated guiding mechanisms and yet provide fast machine cycle time by giving the operator a location at which to load the next garment while the previously loaded garment is being sewn.
It is another object of the present invention to provide apparatus such that pockets may be positioned, folded, and sewn on already finished garments.
It is an additional object of the present invention that the apparatus be a designed with a minimum of moving parts to effect a simple reliable low cost easily maintained apparatus suitable in use in a factory environment where trained technicians are not available.
It is yet another object of the present invention to provide a pocket setting machine in which the set up may be easily changed to accommodate changing workpieces and sewing seam patterns.
Another object of the present invention is to minimize bunching of workpiece materials caused by sliding workpieces over a polished table when they are being pressed together by a workpiece holder.
Other objects of this invention will become apparent from the following summary of the invention and description of the preferred embodiment of the invention.
SUMMARY OF THE INVENTION
The present invention satisfies the need for a simple low cost system that can be used as an automatic pocket setting machine or that can be modified to accomplish other sewing tasks. This automatic sewing machine system is an automatic sewing machine that manipulates a smaller fabric workpiece to a predetermined position on a second fabric workpiece and then sews the two fabric workpieces together. More particularly, this is an automatic pocket setting sewing machine system that folds, places, and sews pockets on an already finished shirt by holding the workpieces stationary while moving the sewing head and needle in a predetermined path. A method is also provided for using this automatic sewing machine system.
The machine can be modified so that it may sew a pocket to other types of garments. Further modifications and adaptions of the machine allow this automatic sewing machine system to accept, fold or otherwise manipulate a second workpiece into a predetermined position on an already loaded and positioned first workpiece. When modified in this manner, the machine system is capable of performing sewing operations on other garment pieces such as sleeves, cuffs, and collars.
The cost of the automatic system is kept low by having the single loading station coupled to the single sewing station by means of a simple inexpensive rotary transfer system. Mounted on the transfer system are a plurality of work plates. The work plates are rotatably supported by the base. As a first workplate is at the loading station being loaded, a second work plate, having been already loaded with workpieces, is at the sewing station and sewing is being accomplished on those workpieces. Clamping means may be used to clamp positioned workpieces to the work plate before the work plates are rotated, during work plate rotation, and during sewing. Locking means are used to lock work plates in position at the sewing station and at the loading station.
The machine system accomplishes sewing by holding the workpieces immobile while the sewing head traverses an extended programmable predetermined sewing pattern. The sewing head is mounted on an X-Y carriage capable of being driven and positioned by programmable computer control. Control over the reciprocation rate of the needle is also provided. Proper program selection determines the seam outline, the rate at which the seam is sewn, and the stitch density and pattern of the seam.
This automatic sewing machine sews a first workpiece to a second workpiece. The machine has a base from which a loading station and a sewing station are positionally defined. A plurality of work plates are moved between the loading station and the sewing station by transport means supported by the base. A plurality of work plates having a work surface are provided, each work plate being moveable by transport means between a first stationary position at the loading station and a second stationary position at the sewing station. At the sewing station, the base supports an extended travel X-Y carriage which has a moveable and positionable travelling surface. The travelling surface is parallel to the work surface of the work plate at the second stationary position at the sewing station.
Optionally, a loading and folding head provides folding means at the loading station. The head is fixed to the base and has an independently controlled center slider and an outer frame. A second workpiece, when positioned on the slider, is engaged by the outer frame. After engagement, folder blades fold the workpiece edges around the slider. After folding, the folded workpiece is positioned on the first workpiece already on the work table. Using this system, the first workpiece and the second workpiece are positioned for further sewing at one location, the loading station, and then transported in their proximate position to the sewing station.
The sewing head is fixed to the moveable and positionable travelling surface of the extended travel X-Y carriage so that the sewing head is moveable in parallel with the positionable travelling surface of the X-Y carriage. The extended X-Y carriage is a simple ball bushing arrangement with each axis being driven by a lead screw powered by a D. C. brushless servomotor. The maximum travel limits of the sewing head are constrained only by the X-Y carriage size which may be as large as a sheet. Travel limits are increased or decreased by suitable changes to the X-Y carriage size and corresponding changes to the length of the lead screws. The X-Y carriage is moved in varying directions at varying speeds by suitable speed and position control over the driving motors. This allows stitch patterns and seam direction to be varied by controlling and programming the X-Y carriage drive means.
Additionally, the machine has an elongated sewing machine needle which reciprocates on its elongated axis, a Z axis that is perpendicular to the plane of the positionable travelling surface, and is driven by a separate variable speed motor which may be a D. C. brushless servomotor. Controlling all motor speeds and position from a central programmable controller causes the needle reciprocation rate to be variable and controllable along with the position and traverse rate of the sewing head. The result is that seams of different outline, shape, stitch pattern, and stitch density may be sewn by altering the underlying computer program.
The front operating or needle end of the upper sewing head is capable of additional movement in the vertical or Z axis. This additional movement is accomplished by pivotally mounting the rear of the sewing head. Rotational movement of the sewing head around the pivot results in the front operating or needle end of the sewing machine describing a large arc, predominantly in the Z axis. The rotational movement is provided and controlled by a pneumatic cylinder.
A stacker is provided to automatically remove the sewn articles from the work plate. The stacker arm is pivotally attached to the base so that the stacker arm moves between a first lower position and a second upper position. Pneumatically actuated stacker fingers have a pinched position and an open position. When the stacker arm rises, the fingers pinch the sewn garment. As the stacker arm lowers, the sewn articles are pulled from the work plate.
The method for sewing a first workpiece to a second workpiece begins by first positioning a first workpiece on a work plate located at the loading station. A second workpiece is then placed over the first workpiece on the work plate. It is within the scope of this invention to optionally place the second workpiece by loading the second workpiece on a slider, folding the edges of the second workpiece around the slider, moving the folded second workpiece and slider to a position on and contacting the already positioned first workpiece resting on the stationary work plate, and finally removing the slider from between the folded second workpiece and the first workpiece. The positioned workpieces and work plate are rotated to the sewing station and held in a stationary position in the sewing station while sewing is being accomplished. The first and second workpieces are sewn together by moving the sewing head with respect to the stationary work plate and workpieces. After sewing is completed, the workpieces are removed from the sewing plate.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other features, aspects, and advantages of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings where:
FIG. 1 is a simplified perspective view of an automatic sewing machine embodying features of the present invention;
FIG. 2 is a front elevational view of the machine of FIG. 1;
FIG. 3 is a top plan view of the machine of FIG. 1;
FIG. 4 is a partial cross sectional view, in vertical longitudinal section, of the main turntable support column;
FIG. 5 is an enlarged fragmentary perspective view of the folding mechanism and turntable mechanism with the outer frame and slider in the down position;
FIG. 6 is an enlarged fragmentary perspective view of the folding mechanism and turntable mechanism with the folding plate assembly in its second folding position; the slider assembly also being in its second folding position;
FIG. 7 is a simplified perspective view of the slider assembly;
FIG. 8a is a side elevational view of the slider assembly; the slider being in its first retracted position and the slider assembly being in its first upper position;
FIG. 8b is a side elevational view of the slider assembly; the slider being in its second extended position and the slider assembly being in its third lowered position;
FIG. 9 is a top plan view of the outer frame folding assembly; the folding blades being in their second retracted position;
FIG. 10a is an enlarged fragmentary cross sectional view showing the component parts of the folding plate assembly;
FIG. 10b is a cross section of the folding plate assembly with a workpiece between the slider and inner plate;
FIG. 10c is a cross section of the folding plate assembly with a folded workpiece resting on the work plate;
FIG. 11 is a vertical cross sectional view of the clamp plate pivot block with the upper locking alignment pin inserted into upper turntable disc locking bushing;
FIG. 12a is a vertical cross section of the clamp and its supporting members, the clamp being in its first raised position;
FIG. 12b is a vertical cross section of the clamp and its supporting members, the clamp being in its second clamping position;
FIG. 13 is a simplified fragmentary perspective view the stacker assembly; and
FIG. 14 is a block representation of the major functional electronic components of the control unit.
DESCRIPTION
General
As best seen in FIGS. 1-3, the automatic pocket setting sewing machine generally comprises a base 30, which supports a main turntable support column 32 at a first end of base 30 and a sewing head support column 34 at a second end of base 30. The main turntable support column 32, better seen in FIG. 4, is of elongated tubular metal construction having main turntable support column mounting ring 36 fixed at its base. The tubular construction allows wiring and pneumatic connections to be routed to the control unit. It should be noted that this description describes a pneumatic system for actuating pneumatic system. A hydraulic system could easily be substituted for the pneumatic system. The sewing head support column 34 is also of elongated tubular metal construction and has a sewing head support column mounting ring 38 fixed at its base. Mounting rings 38 and 36 may be omitted, however assembly of columns 32 and 34 perpendicular to the upper surface of base 30 is facilitated by use of the mounting rings. The longitudinal axis' of sewing head support column 34 and turntable support column 32, when mounted on base 30 must be parallel to each other. The support columns 32 and 34 must also be of sufficient rigidity to support without deflection the mechanisms that are mounted upon each respective column.
Referring back to FIGS. 1-3, a folding group support arm 40 clamped to the main turntable support column 32 supports a folding mechanism 42. The main turntable support column 32 also supports a turntable mechanism 44. The sewing head support column 34 supports an X-Y table mechanism 46 on which is mounted an industrial sewing head mechanism 48. Actuation and synchronization of the various elements and mechanisms is accomplished by pneumatic and electro-mechanical actuation under the central supervision of a microprocessor based control unit 50.
Folding Mechanism
An overall view showing the placement and orientation of the folding mechanism 42 on the folding group support arm 40 is best shown in FIG. 5. Folding group support arm 40 is an elongated bar clamped at its first end to the top of the main turntable support column 32. A tubular rod 52 is welded or otherwise permanently anchored to the second end of folding group support arm 40.
Elongated upper folding cylinder brackets 54, elongated lower folding cylinder brackets 56, and an elongated slider cylinder bracket 60 are clamped over rod 52. Each elongated bracket 54, 56, and 60 has a clamp at one end to provide rigid yet demountable attachment to rod 52. The elongated upper folding cylinder bracket 54 and elongated slider cylinder bracket 60 are vertically mounted extending upwardly away from rod 52. The clamping mechanism allows the brackets to be slightly rotated which in turn compensates for slight inequalities in the extended lengths of cylinders 64, 65, 66, and 67, however other methods of fixing the brackets to rod 52 are effective. The upper ends of upper folding cylinder bracket 54 and slider cylinder bracket 60 are fitted with pivoting connectors 68 allowing upper plate cylinders 64 and upper slider cylinder 66 to pivot in a vertical arc around connectors 68.
Referring to FIG. 5, a first end of elongated lower cylinder brackets 56 is clamped around and downwardly disposed from rod 52. The second lower ends of elongated lower cylinder brackets 56 are bored to receive pivot pin 58 inserted through the bore in each lower cylinder bracket 56. Pivot pin 58 is positioned parallel to rod 52 and serves as a fulcrum about which the remaining folding apparatus move. A first end of elongated folder support arms 62 and the slider fulcrum bracket 70 are bored and pivotally connected to pivot pin 58.
Lower plate cylinders 65 are pivotally attached at the second end of elongated folder support arms 62. Upwardly extending lower plate pistons 65a are connected to the downwardly extending upper plate cylinder pistons 64a. Connection is made at the threaded tips of each piston 64a and 65a by turnbuckle and lock nut means. Use of turnbuckle and lock nut means or other connective means that allows minor overall adjustment in combined cylinder length is preferred.
This mechanical arrangement provides for three detent positions for folding plate assembly 82 when it is vertically positioned by retraction and extension of upper plate pistons 64a and lower plate piston 65a. Folding plate assembly 82 is at its first upper position, best seen in FIG. 2, when upper plate piston 64a and lower plate piston 65a are fully retracted into upper plate cylinder 64 and lower plate cylinder 65. Folding plate assembly 82 moves to its second folding position, best seen in FIG. 6, when lower plate piston 65a is extended while upper plate piston 64a remains retracted. Folding plate assembly 82 moves to its third lowered position, best seen in FIG. 5, when both upper plate piston 64a and lower plate piston 65a are extended.
FIG. 7 depicts a slider assembly 78. An elongated double acting pneumatic slider cylinder 72 is mounted on slider fulcrum bracket 70. Slider cylinder 72 is known in the industry as a rodless type, permitting the slider attachment bracket 76 to be positioned beneath slider cylinder 72. A standard pneumatic cylinder could be used by redesigning the structure supporting the folding plate assembly 82 and the slider assembly 78. Slider 74, made of thin non rusting metal construction is positioned beneath and screwed to slider attachment plate 77 presenting a smooth flat lower surface of slider 74. Optionally attached on the upper surface of slider 74 are slider clips 75. Slider clips 75 may be advantageously used to hold some types of workpieces in position on slider 74. Slider attachment plate 77 is thicker than slider 74 thus giving more support and rigidity to the central portion of slider. The outline shape of slider 74 is shaped to correspond to the shape of the pocket that is to be sewn. Although a pocket shaped slider is herein described, other folded shapes could be provided by suitable changes in the slider outline. In operation, slider 74 can be pneumatically moved between a first retracted position, shown in FIG. 8a, closest to slider fulcrum bracket 70 and a second extended position most distant from slider fulcrum bracket 70 as shown in FIG. 8b.
Stud 80 screwed into slider fulcrum bracket 70 provides pivotal mounting position for lower slider cylinder 67, best seen in FIG. 5. Extending upwardly from lower slider cylinder 67 is lower slider piston 67a. Upwardly extending lower slider piston 67a is connected to the downwardly extending upper slider pistons 66a. Connection is made at the threaded tips of each piston 66a and 67a by turnbuckle and lock nut means similar to those previously described.
The vertical positioning scheme for the slider assembly is similar to that of the folding plate assembly 82. There are three vertical detent positions for slider assembly 78 when it is vertically actuated by movement of upper slider piston 66a and lower slider piston 67a. Slider assembly 78 is at its first upper position, best seen in FIGS. 1 and 8a, when upper slider piston 66a and lower slider piston 67a are fully retracted into upper slider cylinder 66 and lower slider cylinder 67 respectively. Slider assembly 78 moves to its second folding position, best seen in FIG. 6, when lower slider piston 67a is extended while upper slider piston 66a remains retracted. Slider assembly 78 moves to its third lowered position, best seen in FIGS. 5 and 8b, when both upper slider piston 66a and lower slider piston 67a are fully extended.
As best seen in FIG. 5, outer frame 90 is screwed or firmly attached by other connective means to the second end of each folder support arm 62. Design of folder support arms 62 is such that when folding plate assembly 82 is in the down position, shown in FIG. 5, outer plate 90 is resting flat on work plate 202. As best seen in FIG. 9, the inner contour of outer plate 90 is shaped to correspond to the shape of the pocket, however as can be recognized from inspection of FIG. 10a, the contour must be larger than the outline of the pocket by at least the width of folding blade 98. Inner frame 92 is connected and supported at its corners to outer frame 90 by adjustable height dogs 94. Adjusting shims may be placed under dogs 94 at either the outer frame 90 or inner frame 92 to move and adjust the height of inner frame 92 relative to outer frame 90. As best seen in FIG. 9, the outer contour of inner frame 92 is shaped to correspond to the shape of the pocket, however unlike outer frame 90, the contour of the inner frame 92 corresponds in size to that of the pocket to be sewn, as best seen in FIG. 10c. Glued to the lower side of inner frame 92, and extending around its lower periphery, is an inner plate foam pad 110 which serves to keep the second workpiece in position while it is being folded.
Referring to FIGS. 10a, 10b, and 10c, the folding mechanism comprises a folder blade 98 which is attached to a folder spacer 104. The folder spacer 104 is fixed to the side of folder plate 102. The bottom of folder clamp 108 is fixed to the top of folder plate 102. Folder clamp 108 is bored to receive folder cylinder piston 106. Folder cylinder pistons 106 are firmly anchored to folder clamp 108 with a set screw or other such means. Attached to outer frame 90 are single acting spring return pneumatic folding cylinders 96 which actuate folder cylinder pistons 106. Extension of the folder cylinder pistons 106 results in extension of folding blades 98 to a first extended folding position. Retraction of folder cylinder pistons 106 moves folding blades 98 to their second retracted position contiguous to outer frame 90.
FIG. 10b illustrates the folding position. Here the second workpiece 100 is resting on the slider 74. The outer frame 90 is vertically positioned at its folding position; the peripheral edges of the second workpiece 100 are hanging because the folding blades 98 have not been extended.
FIG. 10c illustrates the relative positions of the folding apparatus hardware when the slider assembly 78 and the folding plate assembly 82 have been moved into their third lowered position. Folding blades 98 are extended holding the folded peripheral edges of the second workpiece 100 in the folded position on the work plate 202. From this position the outer frame folding assembly 91 is moved to its first upper position, leaving slider 74 holding the folded second workpiece 202 in position.
Turntable Mechanism
As depicted in FIGS. 1-6, turntable arm 200 is rotationally mounted on main turntable support column 32. Immediately above and below turntable arm 200, concentric to turntable arm 200, and fixedly attached by welding, bolting, or other means to turntable arm 200 are, respectively, upper turntable disc 208 and lower turntable disc 210. Referring to FIG. 4, upper turntable disc 208 and lower turntable disc 210 increase the effective thickness of turntable arm 200 at its center where main turntable support column 32 passes through the assembly. This feature allows a longer turntable arm rotary bearing 212 to be used, thus providing more rigid support for turntable arm rotary bearing 212. A first end of a horizontal work plate 202 is bolted or otherwise fixed to turntable arms 200 providing a work surface over which a first work piece 280 may be loaded. If it is desired to make the machine sew more than one shape of pocket, it is desirable to detachable mount work plate 202 to turntable arm 200. In the preferred embodiment the first workpiece 280 is an already finished pocketless shirt. However, the first workpiece may be any other piece of material, fabric, or plastic, to which a second workpiece is to be attached. As shown in FIG. 10a work plate 202 has opposing edges beveled upwardly to increase the rigidity of work plate 202 and yet keep work plate 202 light. Work plate 202 is of rigid construction but is sprung slightly upwardly when clamp 278 is in its retracted position. When clamp 278 is in its clamping position and is holding the first workpiece 280 and second workpiece 100 in place on work plate 202, work plate 202 is deflected downward into a horizontal position perpendicular to the Z axis of needle 340. As best seen in FIGS. 6, and 10a, a thin strip of work plate foam 206 is glued to the underside of work plate 202 to ensure that fabric workpiece 280 doesn't slip out of position once it has been placed on the work plate 202. Slot 214 is machined through work plate 202 in the outline of the seam to be sewn allowing passage of needle 340 to the lower head 322 during the sewing operation. Slot 214 is a straight sided slot. Work plate foam 206 is shaped to extend from 1/3 to 3/4 of an inch on either side of slot 214 although these dimensions may be expanded or contracted to suit the dimensions of the workpieces and the size of the seam outline. Work plate foam 206 allows work plate 202 to be smooth and non-snagging and yet provides limited non-sliding friction between first work piece 280 and work plate 202 during the folding and loading operations.
Best viewed in FIG. 3, gage plate 204 is anchored to the edge of work plate 202 most distant from turntable arm 200. Gage plate 204 is shaped to approximate the neck and shoulder slope pattern of a shirt to be sewn. This feature allows a shirt to be easily positioned by placing the shoulders and neck of a shirt at a precise location. This provides more repeatable and exact positioning of a shirt allowing pockets to be more accurately placed and sewn. Of course, if first workpiece 280 is another piece of material, such as sleeve or shoulder material, gage plate 204 may be eliminated and replaced with other suitable positioning devices.
As best seen in FIGS. 2 and 4, lower locking cylinder mounting pad 216 is clamped or otherwise fixedly attached to main turntable support column 32 beneath the lower turntable disc 210 and parallel to the lower turntable disc 210. At the main turntable support column 32, the first end of lower locking cylinder mounting pad 216 provides vertical support for the lower thrust bearing assembly 218; at its second outboard end, a double acting pneumatic lower locking cylinder 220 is bolted to lower locking cylinder mounting pad 216. Lower locking cylinder 220 is mounted with lower locking piston 222 extending upwardly through a bore in lower locking cylinder mounting pad 216. In the region of lower locking cylinder 220 the thickness of lower locking cylinder mounting pad 216 is increased to provide a bore extending to close proximity to the top of the lower surface of turntable arm 200. Lower locking bushing 228 is pressed into the bore in the lower locking cylinder mounting pad 216.
A similar bore is provided in turntable arm 200 at an equal radial distance from main turntable support column 32 as is located the lower locking bushing 216. Turntable locking bushing 226 is pressed into the turntable arm bore. These bushings need not be pressed into place but must be fixed in the bore. Other methods such as holding with a set screw are acceptable. At a certain rotational position of turntable arm 200, lower locking bushing 228 and turntable locking bushing 226 come into alignment, allowing lower locking alignment pin 224, threaded onto lower locking piston 222, to be entered into both lower locking bushing 228 and turntable locking bushing 226 at the same time when lower locking piston 222 is extended in an upwardly direction. This upward extension of lower locking alignment pin 224 into both lower locking bushing 228 and turntable locking bushing 226 results in turntable arm 200 being locked in a non rotational mode. Downward retraction of lower locking alignment pin 224 allows turntable arm 200 to freely rotate. For every work plate on which sewing or another operation is to be performed, a locking position is provided. Because three work plates 202 are provided in the preferred embodiment, three detent positions of turntable arm 200 are provided by positioning three turntable locking bushings about the turntable arm 200. Of course, if a different number of detent positions of turntable arm 200 were desired, turntable arm 200 could be equipped with a suitable number of properly positioned detent positions and turntable locking bushings 226.
As best shown in FIGS. 1 and 4, clamp plate pivot block 250 is mounted on main turntable support column 32 above the upper turntable disc 208. Clamp plate pivot block 250 is sufficiently thick to permit insertion of clamp plate pivot block radial bearing 252 in a central bore making clamp plate pivot block 250 rotatable about the axis of main turntable support column 32. Double acting pneumatic upper locking cylinder 254 is bolted, screwed, or otherwise anchored by to the upper surface of the clamp plate pivot block 250, as best shown in FIGS. 3, 5, 6, and 11. Upper locking piston 256, when activated extends downwardly through a bore in clamp plate pivot block 250 into which bore is pressed clamp plate pivot block locking bushing 260. Upper locking alignment pin 258 is threaded in co-axial alignment onto upper locking piston 256.
A bore is provided in upper turntable disc 208 at an equal radial distance from main turntable support column 32 as the bore housing the clamp plate pivot block locking alignment bushing 260; into this bore is pressed upper turntable disc locking alignment bushing 262.
When upper turntable disc 208 is an indexed position, the clamp plate pivot block locking bushing 260 and upper turntable disc locking bushing 262 are in axial alignment. When in axial alignment, upper locking piston 256 may be downwardly extended allowing upper locking alignment pin 258 to be entered into both the clamp plate pivot block locking bushing 260 and upper turntable disc locking bushing 262 at the same time. Extension of upper locking alignment pin 258 into both clamp plate pivot block locking bushing 260 and upper turntable disc locking bushing 262 results in clamp plate pivot block 250 and upper turntable disc 208 being locked and forced to rotate together. Since turntable arm 200 and upper turntable disc 208 are bolted or otherwise fixed together, turntable arm 200 is forced to rotate in unison with clamp plate pivot block 250 when upper locking piston 256 is extended.
As seen in FIGS. 5 and 6, indexing cylinder bracket 266 affixed to folding group support arm 40 supports double acting pneumatic indexing cylinder 264. Indexing piston 268 of indexing cylinder 264 is rotatably connected to pivot block pin 270. Pivot block pin 270 is pressed or otherwise fixed in a bore on clamp plate pivot block 250. Viewed from above, extension of indexing piston 268 rotates clamp plate pivot block 250 in a counter clockwise direction while retraction of indexing piston 268 rotates clamp plate pivot block 250 in a clockwise direction. When upper locking piston 256 is extended, clamp plate pivot block 250 turns turntable arm 200 to which work plates 202 are attached. The machine of the preferred embodiment has three work plates and three detent positions for turntable arm 200 making it desirable for turntable arm 200 to rotate 120 degrees when indexed. To achieve 120 degree rotation, the stroke length of indexing piston 268, radial position of pivot block pin 270 must be considered relative to the placement of indexing cylinder bracket 266 on the folding group support arm 40. Angular index rotation of 180, 120, 90, 72, or 60 degrees could be achieved by suitably modifying component parts and providing turntable arm 200 with 2, 3, 4, 5, or 6 work plates and by providing a suitable number of upper turntable disc locking bushings 262 and turntable locking bushings 226.
As best seen in FIGS. 1, 5, and 6, a double acting pneumatic dual piston flat cylinder is mounted as clamp cylinder 272. Clamp cylinder 272 is bolted or otherwise anchored to a flat side of clamp plate pivot block 250 with clamp pistons 274 downwardly extending. Clamp support 276 is affixed to the lower surfaces of clamp pistons 274. Clamp 278 is screwed or otherwise detachably anchored to clamp support 276. Clamp 278 is a flat piece of metal or other suitably rigid material slotted in the sewing pattern. In the preferred embodiment where the second workpiece 100 is a pocket, the sewing pattern corresponds to the outline of the pocket. There must be sufficient clearance so that reciprocating movement of needle 340 does not cause needle 340 to contact clamp 278. However, the shape of the sewing pattern can be quite complex and is only limited in size to the travel limits of the X-Y table mechanism 46. Clamp 278 is sized to extend outwardly one to one and a half inches from the slotted pattern. The X-Y table mechanism 46 may be quite large depending primarily on the rigidity of its component parts.
As best seen in FIGS. 12a and 12b, when clamp pistons 274 are downwardly extended, clamp 278 presses a second workpiece 100 and a first workpiece 280 against work plate 202. After sewing, clamp pistons 274 retract, raising clamp 278 and allowing workpieces 100 and 280, now sewn together to be removed from work plate 202.
Clamped on main turntable support column 32 above clamp plate pivot block 250 is a shock mount 282 housing a shock absorber 284. Shock absorber 284 is positioned to contact clamp plate pivot block 250 as clamp plate pivot block 250 rotates to its limit in the counter clockwise direction. Shock absorber 284 permits faster counter clockwise rotation of the clamp plate pivot block 250 and turntable arm 200 assembly and minimizes impact damage to the turntable mechanism 44 when the folded and loaded first workpiece 280 and second workpiece 100 are rotating into position beneath the upper sewing head 324. A small orifice drilled through the rear end of indexing cylinder provides allows a second shock absorber to be mounted on the back of indexing cylinder 264. This second shock absorber, directly connected to the air inside indexing cylinder 264, provides shock absorption when clamp plate pivot-block 250, moving in a clockwise direction, is approaching the folding mechanism 42.
FIGS. 1, 2, 3, and 13 best illustrate placement, construction, and operating limits of the stacker assembly 400. FIGS. 1 and 2 show stacker table 414 but stacker table 414 is omitted from FIGS. 3 and 13 to better illustrate stacker assembly 400. Stacker table 414 is a rigid device easily made of metal, fiberglass, or other suitable materials over which finished garments may be laid. As the garments are removed from the sewing machine and draped over the stacker table 414, a first portion of a garment would be on the side of the stacker table 414 closest to the sewing machine and the second remaining portion of a garment would be draped over the side of stacker table 414 away from the sewing machine.
Stacker arm 404 is pivotally attached to stacker bracket 402 which is anchored to a location at the bottom of the front side of base 30. Stacker cylinder bracket 406, anchored to the front side of base 30 at a location vertically above that of stacker bracket 402, serves to pivotally support stacker cylinder 408. Stacker cylinder piston 410 is pivotally clamped to stacker arm 404 allowing stacker arm 404 to be moved between a first lowered position, as illustrated in FIG. 13, and a second raised position. Clamped over stacker arm 404 are double acting pneumatic stacker fingers 412, which may be pneumatically activated to a first closed pinching position; reverse pneumatic pressure opens stacker fingers 412 to a second open position.
X-Y Mechanism
Referring to FIG. 2, at a second end of base 30, sewing head support column 34 is fixed in a vertical position by its attachment to sewing head mounting ring 38 and base 30. X-Y base 300 is a rectangular plate fastened perpendicular to sewing head support column 34. A conventional X-Y carriage, well known in the industry, is affixed atop X-Y base 300 by anchoring two parallel rails 302 to the top side of X-Y base 300, placing two ball bushing style type pillow blocks of a type well known in the industry on each parallel rail 302 and affixing to the top side of said pillow blocks a conventional dual shaft rail system 304, FIG. 2, with its shafts running perpendicular to parallel rail 302. A lead screw and mating ball screw are provided to drive each axis. The individual components and systems are well known in the industry and may be found in the product line manufactured by Thompson Industries, Inc. of Port Washington, N.Y. The lead screws are driven and controlled by X Axis servomotor 310 and Y Axis servomotor 312. Servomotors 310 and 312 are conventional brushless D.C. Servomotors that allow them to be computer controlled. Bolted or otherwise fastened to the top of dual shaft rail system 302 is rectangular sewing head mounting base 320, which is a positionable travelling surface, onto which sewing head 48 is fastened.
Sewing Head Mechanism
Sewing head 48 operates in a conventional manner that is well known in the sewing industry. As better seen in FIG. 3, sewing head 48 has a lower head 322 that is offset to the rear of the machine from the centerline of upper head 324. Sewing head 48 has conventional hook and knife trimming apparatus that are common in the industry. However, offsetting lower head 322 requires rerouting the drive mechanisms for the lower head hook and knife trimming apparatus.
Sewing head 48 is driven by sewing head servomotor 314, mounted on the sewing head base 320 and connected by drive shafts, belts, and pulleys to the needle 340 in the upper head 324 and to the hook and knife trimming mechanisms in the lower head 322. Sewing head servomotor 314 is conventional brushless D. C. Servomotor that allows the speed of the motor to be computer controlled. Needle 340 is a pointed elongated cylindrical member that reciprocates in a Z axis, a direction perpendicular to the X-Y axis travel of the travelling positionable surface. Sewing head servomotor 314 drives the Z-axis movement of needle 340. It should be noted that servomotors are not the only means to drive movement on the X, Y, and Z axis. Other motive means include combinations of linear motors and other rotationally controllable motors.
Upper head 322 is pivotable on sewing head pivot 328. Sewing head pivot 328 is mounted at the top of sewing pivot block 326 which is fixed directly on sewing head base 320. Sewing head base bracket 332 is attached to sewing head base 320 and sewing head bracket 336 is anchored at the rear of upper head 324. Pivotally connected to sewing head base bracket 332 is a double acting pneumatic sewing head cylinder 336. Sewing head cylinder piston 338 is pivotally connected to sewing head bracket 334. Extension of sewing head cylinder piston 338 positions upper head 324 in its first or down position. This is the position in which sewing is accomplished. Retraction of sewing head cylinder piston 338 raises upper head 324 to its second upper position. Upper head 322 is in the second upper position when work plate 202 is being rotated under upper head 322 and when the sewn workpieces are being removed from the machine.
Electro-Pneumatic Control
Horizontal position and speed of sewing head 48 are controlled by movement of X axis servomotor 310 and Y axis servomotor 312. Appropriate computer control allows needle 340 to traverse the stitch pattern on the garment by traversing the X-Y path of the sewing seam. Stitch density is controlled by varying the slewing speed of X-Y axis moment and the rate at which needle 340 is reciprocating in the Z axis.
All pneumatic cylinders are extended and retracted by suitable solenoid operated pneumatic valves well known in the industry. The solenoids are individually controlled by the I/O interface of the microcomputer controller. Cylinders on the sewing machine are equipped with reed switches that provide feedback to the microcomputer controller as to the position of the piston, ie. whether the piston is extended or retracted. The reed switch feedback provides information to the computer about the status of each pneumatic cylinder in turn allowing the computer to monitor and control the machine operation. These types of mechanisms and features are well known and are available as standard components from sources in the pneumatics industry.
Individual mechanical and pneumatic functions of the sewing machine are computer controlled, as seen in FIG. 14, by means well known in the computer control industry. This type of control system is well known in the electrical control industry and requires only standard components. A suitable control system is the DMC-1000 Series motion controller manufactured by Galil Motion Control, Inc. of Sunnyvale, Calif. This control system is capable of controlling the X, Y, and Z axis servomotors as well as the numerous inputs and outputs of the reed switches that detect the piston position and the solenoids powering the numerous pistons
Operation
Operation of the sewing machine is described by assuming that the machine has just completed sewing and stacking operations and that positionable elements or assemblies are at their following respective positions: upper sewing head 324 is in its first up position; stacker arm 404 is in its first lowered position, stacker fingers 412 are in their second open position; clamp 278 is in its first raised position; indexing cylinder 264 is in its second extended sewing position; lower locking lignment pin 224 is in its first extended locked position; upper locking alignment pin 258 is its first extended locked position; folding plate assembly 82 is in its first upper position; folding blades 98 are in their second retracted position; slider assembly 78 is in its first upper position; and slider 74 is at its first extended position.
A machine operator first places a first workpiece 280, in this case, a pocketless shirt, over gage plate 204 and work plate 202. A shirt may be seen positioned on the gage plate 204 and work plate 202 on FIG. 13, however this shirt is at the sewing station and not in the loading position. The appropriate gage plate 204 and work plate 204 on which the first workpiece is loaded is under folding mechanism 42. This first workpiece 280 is pulled over and around the work plate 202 so that the front of the first workpiece 280, a shirt front, lies on the upper surface of workplate 202. The waist area of the shirt is bunched around work plate 202 in the vicinity of turntable arm 202.
Slider assembly 78 is moved to its second folding position, thus preparing the slider 74 for loading of the second workpiece 100. The second workpiece 100 is laid on top of slider 74 and the slider attachment plate 77. In the preferred embodiment, the second workpiece is a pocket blank that has fabric material extending one quarter to one half of an inch beyond the sides of the slider 74. The pocket blank may have its top seam already sewn. A pocket would be positioned with the pocket top closest to the slider attachment bracket. A pocket would have its finished side facing up after it was loaded. The pocket may be held in place with slider clips if necessary.
The machine is now activated, lowering folding plate assembly 82 from its first upper position to its second folding position pressing lightly against slider 74. This position is best seen in FIG. 6. Folder blades 98 are now actuated to their first extended folding position, folding the peripheral edges of the second workpiece 100 around the sides of slider 74. After folding, and while folder blades 98 are extended, upper plate pistons 64a and upper slider piston 66a are extended together lowering both slider assembly 78 and folding plate assembly 82 together to a position on work plate 202. Slider assembly 78 is now in its third lowered position and folding plate assembly is in its third lowered position. This position is best seen in FIG. 5. Folding blades 98 are now moved to their second retracted position allowing folding plate assembly 82 to be raised to its first upper position. At this point in the machine operation, the second workpiece 100 is held against work plate 202 by the downward pressure of slider 74 against the folded edges of the second workpiece 100.
Lower locking piston 222 is extended locking turntable arm 200. Upper locking piston 256 is retracted allowing clamp plate pivot block 250 to rotate independently of turntable arm 200. Indexing piston 264 is retracted, moving clamp plate pivot block 250 and the attached clamp cylinder 272 and clamp 278 to a position over slider 74. Upper locking piston 256 is extended into corresponding turntable locking bushing 262 causing clamp plate pivot block 250 and turntable arm 200 to be locked together. Meanwhile lower locking alignment pin 224 is still extended causing turntable arm 200 to be locked in a non-rotational mode.
Clamp pistons 274 are now extended causing clamp 278 to move from its first raised position to its second clamping position. Clamp 278 is now holding the second workpiece 100 against the first workpiece 280. Slider 74 is still in its second extended position, between the first workpiece 280 and second workpiece 100 and under clamp 278. Now, pressure is released in upper slider cylinder 66 and slider 74 is moved to its first retracted position. Slider assembly 78 is now moved to its first upper position. Folded first workpiece 280 and second workpiece 100 are now clamped to work plate 202 by downward pressure of the clamp pistons 274.
Lower locking piston is now retracted moving lower locking alignment pin 224 to its second retracted rotational position. Since upper locking alignment pin 258 is extended, locking clamp plate pivot block 250 and turntable arm 200 together, extension of indexing piston 268 at this time, results in turntable arm 200, rotating counter clockwise, moving the clamped together workpieces beneath the upper sewing head 324. Action of clamp plate pivot block 250 against first shock absorber 284 correctly positions clamp plate pivot block 250 and reduces shock to the surrounding structure. Lower locking piston now extends causing lower locking alignment pin 224 to move to its first extended locked position and locking turntable arm 200 in a non rotational mode.
A new work plate 202 is now at the folding mechanism ready to be loaded with a new first workpiece 280 as previously described. The loading and folding operation can take place on the new first workpiece 280 while the machine sews the original first workpiece 280 and second workpiece 100 as will now be described.
Sewing head piston 338 is extended moving upper sewing head 324 to its down sewing position. Sewing is done under computer program control of sewing head servomotor 314, X axis servomotor 310 and Y axis servomotor 312, resulting in needle 340, sewing the first workpiece 280 and second workpiece 100 together, tracing the proper stitch outline around bevelled clamp slot 279 and stitching with the proper stitch density.
After sewing is completed, sewing head piston 338 is retracted raising upper sewing head 324 to its first up position. Now clamp piston 274 is retracted moving clamp 278 to its first raised position.
With sewing complete and the work pieces ready to be removed from the sewing station, stacker arm 404 is moved to its second raised position by retraction of stacker cylinder piston 410 with stacker fingers 412 in their second open position. With stacker arm 404 at its second raised position, stacker fingers 412 surround the workpieces or garment that has just been sewn. Stacker fingers 412 now close to their first pinching position and grasp the garment. With stacker fingers 412 in their first pinching position, stacker cylinder piston 410 is extended, thus lowering stacker arm 404 and pulling the garment off work plate 202 to a position draped over stacker table 414. With stacker cylinder piston 410 partially extended and stacker arm 404 part way to its first lowered position and the garment draped over stacker table 414, stacker fingers 412 are moved to their second open position thus releasing the garment. With stacker fingers 412 now in their second open position, stacker cylinder piston 410 continues to extend and finally moves stacker arm 404 to its first lowered position.
The previously described versions of the invention have many advantages, including the ability to sew a pocket on a previously completed shirt. Changing pocket shapes, garment, and seam patterns are easily accommodated by software changes and minor changes to a few component parts. Bunching of workpiece materials caused by sliding workpieces over flat tables is eliminated because workpiece materials, once clamped, are not moved by sliding. Because this sewing machine allows an operator to load subsequent workpieces while previous workpieces are being sewn, and the machine accomplishes loading and folding at one work station, where the folding mechanism 82 is located, machine cycle time is fast. Moreover, the simple construction with a minimum number of moving parts results in a low cost machine that is easily maintained.
Although the invention has been described in considerable detail with reference to the preferred embodiment and other illustrative embodiments, the claims are not limited to these embodiments, but rather are directed to all modifications and variations that are within the spirit and scope of this invention and that may be conceived and reduced to practice by those skilled in the art. | An automatic sewing machine system for sewing a small workpiece to a larger workpiece by moving the sewing head and needle along an extended predetermined path while the workpieces remain stationary. Also provided is a method for using this system. The larger workpiece is positioned on a rotating work plate before the smaller workpiece is loaded in folding apparatus that folds and positions the smaller workpiece in a predetermined position on the larger workpiece. A clamp mechanism secures the workpieces to the work plate before the work plate is rotated under the sewing head and locked in a stationary position. The sewing head is mounted on a programmable computer controlled extended travel X-Y carriage allowing programmable and automatic control of the seam pattern and the rate at which the sewing head traverses the seam pattern. Stitch density is controlled by adjusting the programmable variable speed reciprocation rate of the sewing head needle in conjunction with the rate at which the sewing head traverses the seam pattern. After the machine is loaded, the system automatically folds and positions the workpieces on the work plate and clamps the workpieces before the work plate is rotated under the sewing head. The work plate is locked in position while a predetermined stitch pattern is applied to sew the workpieces. | 3 |
BACKGROUND OF THE INVENTION
The present invention relates to a method of backwashing, by heating, a particulate filter adapted to purify exhaust gases from an internal combustion engine, in particular an internal combustion engine equipping an automobile vehicle.
DESCRIPTION OF THE RELATED ART
A particulate filter conventionally comprises honeycomb porous structures forming filter bodies for filtering particles emitted by diesel vehicles. These filter bodies are generally made of ceramics (cordierite, silicon carbide, etc.). They may be of one-piece construction or consist of various units. In the latter case, the units are assembled by bonding them together with a ceramic cement. The resulting assembly is then machined to the required cross section, which is generally round or oval. The resulting filter body may comprise a plurality of passages, closed at one end or the other, which may have cross sections with different shapes and diameters. The filter body is generally inserted into a metal enclosure, for example as described in FR-A-2 789 327.
In use, soot accumulates in the passages of the filter body, in particular in the inlet passages, which increases the head loss caused by the filter body and therefore degrades the performance of the engine. For this reason, the filter bodies must be regenerated regularly, for example every 500 kilometers.
Regeneration, also known as “backwashing”, consists in oxidizing the soot. It is necessary to heat the filter to achieve this. The flash point of soot is of the order of 600° C. under standard operating conditions but the temperature of the exhaust gases is on average only of the order of 300° C. However, it is possible to add additives to the fuel to catalyze the soot oxidation reaction and reduce the flash point to approximately 150° C.
The exhaust gases or the filter body may be heated, or the soot may be heated directly. Different techniques have been developed.
One recent approach is local heating, on the upstream side of the filter body, in such a manner as to initiate combustion, which then propagates progressively into the whole of the filter body. This type of technique is described in FR A 2 771 449 and DE-A-19530749, for example.
The heating means are generally connected to an electrical power supply of the vehicle.
They may comprise ceramic plugs, for example diesel engine glow plugs, simple electrical elements, or ceramic igniters, as described in French patent application No. 0013998 filed Oct. 31, 2000 by the Applicant.
The engine operating conditions may vary considerably between starting the regeneration process, i.e. turning on the heating means, for example the ceramic igniters, and the moment at which the soot actually ignites. Variation in operating conditions can greatly degrade efficiency.
SUMMARY OF THE INVENTION
The object of the invention is to provide a backwashing method that limits the degradation of the efficiency of regeneration of the filter.
The above object is achieved by a method of backwashing by heating a particulate filter for purifying exhaust gases from an internal combustion engine, in particular an internal combustion engine equipping an automobile vehicle, noteworthy in that starting of the heating means for the filter is commanded when said engine is delivering an engine torque below a predetermined bottom threshold.
It has been found that, under these engine operating conditions the ignition of the soot accumulated in the filter body of the filter and the propagation of the combustion of the soot are not greatly influenced by the engine operating conditions. Thus by controlling the heating means in accordance with the invention, efficient regeneration of the filter is achieved, substantially independently of variations in the engine operating conditions.
Thus the starting of said heating means is preferably commanded only if the engine is delivering an engine torque below said low threshold.
According to other features of the invention:
starting of said heating means is commanded when said engine is idling or in the absence of combustion in said engine;
said bottom threshold is less than or equal to 10% of the maximum engine torque of said engine;
starting of said heating means is commanded after said engine has delivered an engine torque exceeding a top threshold for at least a predetermined time period;
said top threshold is greater than or equal to 30% of the maximum engine torque of said engine;
said predetermined time period is greater than or equal to one minute;
starting of said heating means is commanded only if said filter and/or said engine are at temperatures exceeding respective threshold temperatures;
starting of said heating means is commanded after detection of a minimum mass of soot in said filter;
starting of said heating means is commanded at the latest one minute after said engine has begun to deliver an engine torque below said bottom threshold;
starting of said heating means is commanded as soon as said engine has begun to deliver an engine torque below said bottom threshold;
said heating means are maintained in operation for at least five seconds after starting;
said engine torque delivered by said engine is evaluated by measuring a position of an accelerator pedal;
said heating means comprise a hot tip whose temperature increases from a temperature greater than or equal to 20° C. to a temperature greater than or equal to 1000° C. within six seconds of being started;
said heating means comprise Mini-Igniter® type igniters.
The invention also provides a device for implementing the above backwashing method, said device comprising heating means for heating said filter, control means for controlling said heating means, and a computer for managing said control means.
The device is noteworthy in that it further comprises detection means for detecting the delivery by said engine of an engine torque below a predetermined bottom threshold, said computer commanding starting of said heating means in response to said detection.
According to other features of the device of the invention:
said heating means are adapted to heat by direct contact particles deposited on a filter body of said filter;
said heating means comprise at least one ceramic igniter;
hot tips of said heating means are disposed inside said filter body or on an outside lateral surface of said filter body, preferably without projecting from said surface;
the device includes detection means for detecting rotation of said engine.
BRIEF DESCRIPTION OF THE DRAWING
Other features and advantages of the present invention will become apparent on reading the following description and from the appended drawing in which the single FIGURE is a diagrammatic representation of a device constituting a preferred embodiment of the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The device of the invention represented in FIG. 1 comprises ceramic igniters 1 disposed in such a manner as to be able to heat a particulate filter F for purifying exhaust gases G from an internal combustion engine M of a vehicle V.
The ceramic igniters may equally be disposed in such a manner as to heat the gases G or to heat the soot directly.
The ceramic igniters 1 are small components which, when an electrical current flows in them, are locally heated to a very high temperature (1200 to 1400° C.). These igniters are usually made of a highly resistive ceramic material such as silicon carbide, sometimes mixed with other ceramic components.
The ceramic igniters are preferably those described in U.S. Pat. Nos. 5,085,804 and 5,045,237.
The igniters described in U.S. Pat. No. 5,085,804 comprise a hot region consisting primarily of a sintered mixture of 5 to 50% by volume of molybdenum disilicide and 50 to 95% by volume of a mixture of silicon carbide and silicon nitride.
The open pore content is less than or equal to 4% and the bending resistance at the standard threshold is at least 207 MPa (30 000 psi).
The ratio between the resistivity at room temperature and the resistivity at 1200° C. of the igniters described in U.S. Pat. No. 5,085,804 is less than 19.8, but may be as low as 0.2. A ratio of this magnitude indicates a very short response time, the response time varying in the same direction as this ratio.
The hot region of the igniters described in U.S. Pat. No. 5,085,804 may be defined as follows:
(1) Thickness or width of at least 0.0508 cm (0.020 in) or cross section area of at least 0.00258 cm 2 (0.0004 in 2 ).
(2) Thickness or width of at most 0.127 cm (0.050 in) or cross section area of at most 0.0161 cm 2 (0.0025 in 2 ).
(3) For narrow cross sections, hot region lengths at most approximately 2.53 cm (1 in), the length/area ratio being at most approximately 2500 to 0.0258 cm 2 (0.004 in 2 ).
(4) For short, fat shapes, a hot region length of at least 0.508 cm (0.2 in).
The igniters described in U.S. Pat. No. 5,045,237 have a hot region consisting primarily of a sintered mixture of 5 to 50% by volume of molybdenum disilicide and 50 to 95% by volume of a mixture of silicon carbide and aluminum nitride. The other features and performance of these igniters are similar to those of the igniters described in U.S. Pat. No. 5,085,804.
Detailed information on the structure and the fabrication of the ceramic igniters may be found in NORTON COMPANY's U.S. Pat. Nos. 5,191,508, 5,085,804, 5,045,237, 4,429,003 and 3,974,106.
The ceramic igniters 1 are preferably disposed to heat particles deposited on a filter body of the filter.
The hot tips of the ceramic igniters 1 are preferably inside the filter body of the filter F, the ceramic igniters being pushed wholly or partially into the filter body.
This has the advantage of enabling efficient transmission of heat energy to the soot accumulated in the filter body of the filter F.
In one variant of the invention, the ceramic igniters are on the substantially cylindrical outside lateral surface 2 of the filter body, and are preferably pushed into housings, which are preferably of complementary shape, formed in the surface 2 . The shape of the housings is preferably determined so that the igniters do not project from the surface 2 .
For more detailed information on the disposition of the ceramic igniters see French patent application No. 0013998.
However, the invention is not limited to heating through direct contact of the heating means with the particles of soot. The exhaust gases or the filter body may be heated.
The ceramic igniters 1 are connected by electrical wires 3 to control means 5 adapted to supply them selectively with an ignition electrical current.
According to the invention, this device further comprises a computer 7 for managing the control means 5 and evaluation means 9 for evaluating the engine torque delivered by the engine M, for example by measuring the position of an accelerator pedal 10 .
The evaluation means 9 for evaluating the engine torque are connected by a line 11 to the management computer 7 .
The device of the invention preferably further comprises measuring means 13 for measuring the clogging of the filter F and detection means 15 for detecting rotation of the engine M transmitting data to the computer 7 via lines 17 and 19 , respectively.
The device of the invention operates in the following manner.
The measuring means 13 for measuring the clogging of the filter F inform the computer 7 if they detect a degree of clogging necessitating the starting of a regeneration operation.
The computer 7 advantageously verifies that the following conditions a) and b) are satisfied before turning on the ceramic igniters 1 :
a) The engine M is running, which enables renewal of the air in the filter F. If the air is not renewed, the combustion of the soot quickly stops.
The computer 7 is informed by the means 15 of the running or stopped state of the engine M.
b) The filter is warm, i.e. its temperature exceeds a minimum temperature.
The computer 7 preferably considers that this latter condition is satisfied when the engine M has just delivered an engine torque exceeding a predetermined top threshold C top for a predetermined time period, for example while the vehicle V is travelling a few kilometers. The top threshold C top is preferably set to a value greater than or equal to 30% of the maximum engine torque C max that the engine M may provide. The predetermined time period is preferably at least one minute.
According to the invention, when the two conditions a) and b) are satisfied, the computer 7 waits for a third condition c) to be satisfied, namely that the engine M is delivering an engine torque below a predetermined bottom threshold C bottom .
The bottom threshold C bottom is preferably less than or equal to 10% of the maximum engine torque C max .
The engine M delivers an engine torque below the bottom threshold C bottom in two main situations in particular: in the absence of combustion, and when idling.
The term “absence of combustion” (in the engine) refers to phases of operation of the engine during which no combustion occurs in any of the cylinders of the engine.
In a vehicle propelled by an internal combustion engine, these phases occur in particular when the injection of fuel is cut off because the driver of the vehicle ceases to depress the accelerator pedal 10 . In a hybrid “thermal—electrical” vehicle, these phases may also occur when the electric motor is supplying all of the power for propelling the vehicle. For regenerating the filter F, it is nevertheless necessary to keep the thermal engine M running, to satisfy condition a).
The evaluation means 9 supply to the computer 7 an estimate of the motor torque delivered by the motor M as a function of the position of the accelerator pedal 10 . This allows the computer 7 to determine when the engine M is delivering an engine torque below the bottom threshold C bottom or above the top threshold C top .
The condition c), whereby the engine M must deliver an engine torque below the bottom threshold C bottom , is required prior to turning on the ceramic igniters in order for the exhaust gases G coming from the engine M and entering the filter F to retain a high oxygen content, to encourage ignition of the soot present in the filter F and the propagation of combustion to all of the soot in the filter body.
As soon as possible after the condition c) is satisfied, and preferably within a maximum delay of one minute, the computer 7 causes the control means 5 to pass an ignition electrical current through the ceramic igniters 1 .
In one variant of the invention, the computer 7 commands the turning on of the ceramic igniters 1 as soon as condition c) is satisfied, without necessarily checking the degree of clogging of the filter beforehand, or its temperature, or for rotation of the engine. This reduces the probability of ignition of the soot, but simplifies the architecture of the device.
The ceramic igniters 1 have a very short response time. Although standard spark plugs take from 10 to 40 seconds to reach 1000° C., the ceramic igniters 1 take only 3 to 6 seconds to achieve the same temperature. This is crucial since if heating is not fast enough, the soot tends to be consumed without igniting, rather than tending to ignite, which impedes the propagation of combustion.
The ceramic igniters 1 preferably have a rate of increase of temperature exceeding 150° C./s, more preferably greater than 200° C./s, and even more preferably greater than 300° C./s.
The ceramic igniters preferred for the invention are Mini-Igniters® from SAINT-GOBAIN ADVANCED CERAMICS, the characteristics of which are summarized in Table 1 below.
TABLE 1
Preferred Mini-Igniters ®
Mini-Igniter ® model
300
401
601
405
600
Time for temperature
3 s
3 s
5 s
<2 s
<6 s
to increase to nominal
temperature from
room temperature
Continuous electrical
1.5 to 2.5 A
1.0 to 2.2 A
0.4 to 1.2 A
0.4 to 0.6 A
0.2 to 0.75 A
current
at 12 V
at 24 V
at 120 V
at 24 V
at 120 V
Electrical resistance
1.0 to 6.0
1.0 to 6.0
25 to 300
1 to 100
25 to 600
at room temperature
Ohms
Ohms
Ohms
Ohms
Ohms
Nominal temperature
from 1035
1275 to
1275 to
from
1150 to
to 1580° C.
1455° C.
1455° C.
1050 to
1400° C.
at 24 V
at 120 V
1500° C.
at 120 V
Given the voltages usually available in automobile vehicles, the 300 models operating at 12 volts and the 401 and 405 models operating at 24 volts are preferred.
The phases of operation of the engine during which it delivers an engine torque below the bottom threshold C bottom generally last a few seconds, for example the time taken by the vehicle V to slow down and stop. For these few seconds to be sufficient to turn on the heating means and ignite the soot, it is advantageous for those means to have a very short response time.
The ceramic igniters 1 are therefore particularly adapted to the management method of the invention, especially as they provide for positioning the hot tips within the filter body.
The computer 7 maintains the ignition electrical current through the ceramic igniters 1 for a predetermined time period, preferably at least 5 seconds.
The ignition electrical current is preferably maintained throughout this predetermined time period, even if in the meantime the engine torque supplied by the engine M again exceeds the bottom threshold C bottom .
The method of the invention is advantageously applicable to any heating means, but especially heating means whose response time enables the soot to be ignited during a phase of absence of combustion, i.e. within a maximum time period of around 10 seconds in the case of a thermal vehicle.
The combustion of the soot continues until all of the soot has been consumed or the conditions for combustion are no longer satisfied. In the latter case, the soot is extinguished spontaneously.
Of course, the present invention is not limited to the embodiment described and shown by way of illustrative and nonlimiting example.
In particular, it is not limited to one particular type of filter. For example, it is applicable whether the filter F is catalytically assisted or not.
It also encompasses filters through which pass exhaust gases resulting from the combustion of a fuel to which one or more additives have been added, in particular an additive intended to catalyze the reaction of oxidation of the soot and/or to reduce its flashpoint.
Finally, any heating means having a hot tip whose temperature may be increased from room temperature of 20° C. to a temperature of 1000° C. or greater within 6 seconds from its nominal energization is suitable for implementing the invention. | A method is provided for backwashing, by heating, a particulate filter to be purified of exhaust gases (G) of an internal combustion engine (M), in particular an internal combustion engine equipping a motor vehicle (V). The method includes controlling the start-up of a device for heating ( 1 ) the filter (F) when the engine (M) delivers an engine torque at a predetermined low threshold (C bas ). | 8 |
RELATED APPLICATIONS
This application is a continuation-in-part of U.S. patent application Ser. No. 534,756 filed Dec. 2, 1974 now U.S. Pat. No. 4,089,336, which is a continuation of U.S. patent application Ser. No. 63,645 filed Aug. 13,1970, now abandoned, which is a continuation of U.S. patent application Ser. No. 681,737 filed Nov. 9, 1967, now abandoned.
BACKGROUND OF THE INVENTION
The control of bleeding during surgery accounts for a major portion of the total time involved in an operation. The bleeding that occurs from the plethora of small blood vessels that prevade all tissues whenever tissues are incised obscures the surgeon's vision, reduces his precision, and often dictates slot and elaborate procedures in surgical operations. It is well known to heat the tissues to minimize bleeding from incisions, and surgical scalpels which are designated to elevate tissue temperatures and minimize bleeding are also well known. One such scalpel transmits high frequency, high energy sparks from a small electrode held in the surgeon's hand to the tissues, where they are converted to heat. Typically, substantial electrical currents pass through the patient's body to a large electrode beneath the patient, which completes the electrical circuit. Discharge of sparks and temperature conversion in the tissue are poorly controlled in distribution and intensity, and erratic muscular contractions in the patient are produced so that this apparatus cannot be used to perform precise surgery. Further, apparatus of this type frequently produce severe tissue damage and debris in the form of charred and dead tissue, which materially interfere with wound healing.
Another well-known surgical scalpel employs a blade with a resistive heating element which cuts the tissue and provides simultaneous hemostasis. Although these resistive elements can be readily brought to a suitably high and constant temperature in air prior to contacting tissues, as soon as portions of the blade in contact with tissues, they are rapidly cooled. During surgery, non-predictable and continuously varying portions of the blade contact the tissues as they are being cut. As the blade cools, the tissue cutting and hemostasis become markedly less effective and tissue tends to adhere to the blade. If additional power is applied by conventional means to counteract this cooling, this additional power is selectively delivered to the uncooled portions of the blade, frequently resulting in excessive temperatures which may result in tissue damage and blade destruction. This results from the fact that in certain known resistively heated scalpels, the heating is a function of the current squared times the resistance (I 2 R). In conventional metallic blades of this type, the higher the temperature of any blade portion, the greater its electrical resistance, and consequently the greater the incremental heating resulting from incremental power input.
It is generally recognized that to seal tissues and effect hemostasis it is desirable to operate at a temperature between 300° C. and 1000° C. And for reasons noted above, it is desirable that electrothermal hemostatic surgical cutting instruments include a mechanism by which power is selectively delivered to those portions of the blade that are cooled by tissue contact so that the cutting edge may be maintained at a substantially uniform operating temperature within the desired optimal range. Recently, hemostatic scalpels have been described (see, for example, U.S. Pat. Nos. 3,768,482 and 3,826,263) in which the temperature-controlling mechanisms include resistive heating elements disposed on the surface of the scalpel blade. However, such instruments require precision in fabricating the dimensions of the heating elements to obtain the desired resistances. And such resistive heating elements may be subjected to variations in resistance during use, as tissue juices and proteins become deposited upon the surface of the blade.
SUMMARY OF THE INVENTION
The present invention provides a surgical cutting instrument in which the temperature of the cutting portion of the blade is elevated and maintained within a preselected and relatively constant temperature range along its length by conducting heat to the cutting edge from a thermal distribution means in which heat absorbed by evaporation of a fluid is subsequently released by condensation of that fluid to selectively heat those portions of the cutting edge that are cooled upon contact with tissue being cut. The thermal distribution means consists of a closed evacuated chamber containing both a fluid and a capillary action liquid transport means for returning the condensed liquid to the heat source, and is disposed in the region of the blade along its cutting edge.
A heat source is coupled to the thermal distribution means to elevate the temperature of the fluid contained therein above its solidification temperature, which temperature is within or slightly above the preselected operating temperature range of the cutting edge. Heating of the cutting edge is provided by thermal conduction from the chamber wall. Selective heating of regions of the cutting edge that are locally cooled upon contact with tissues being cut is provided for by condensing the previously-vaporized fluid on the contiguous cooled portions of the chamber wall to release a portion of the thermal energy which was previously stored in the vapor and which was required to convert the fluid from its liquid phase to its vapor phase. The condensed liquid is transported by capillary action of a wick-like structure disposed along the wall of the chamber to the region of the heat source where it is once again vaporized. This removes the liquid from the capillary action transport means and stores thermal energy therein. The vapor phase of the liquid is transported to cooled regions of the chamber by local pressure differentials within the chamber which result from (1) the pressure increments associated with vaporization, and (2) from the pressure decrements associated with condensation. The vaporized fluid thus stores thermal energy at substantially the temperature at which the vapor is created and releases stored thermal energy upon contact with colder surfaces. Whenever and wherever the vapor encounters a colder surface, the vapor condenses and releases the heat previously required to vaporize the liquid. The processes of vaporization and condensation are essentially independent and are interrelated only by streams of vapor and liquid in the chamber. The result is that the temperature along the entire length of the chamber tends to remain constant, and the temperature of the cutting edge of the blade which is thermally coupled to the chamber along its length thus also tends to remain constant.
Thermal conduction from the thermal distribution means to the cutting edge occurs substantially from only the relatively small portion of the chamber wall contiguous to the cutting edge. An electric heating element is disposed along the length of the chamber wall about a circumferential portion thereof which is opposite the cutting edge. This longitudinal disposition of the electric heating element along those portions of the chamber which are opposite to the portions of the chamber that are contiguous to the cutting edge permits more efficient operation of the thermal distribution means for three reasons. First, the large surface areas of the chamber wall that are contiguous to the electric heater do not require condensation of previously evaporated working fluid with concomitant release of heat to bring these portions of the thermal distribution means to the elevated operating temperatures required for hemostasis. Second, the longitudinal arrangement of the electric heating element allows the vapor to be transported from the regions of the chamber contiguous to the electric heater to nearby regions of the chamber that are contiguous to the cutting edge substantially along lateral (i.e., diametric paths, rather than primarily along longitudinal paths running through the length of the chamber. Third, the longitudinal disposition of the electric heating element upon the chamber wall results in much of the capillary transport of condensed liquid occurring along circumferential rather than longitudinal paths. These shorter vapor and liquid paths result in shorter, quicker and more efficient cycling of the working fluid.
Because the longitudinal disposition of the electric heater means results in shorter vapor transport paths, the vapor conducting channel of the thermal distribution means can be reduced to a size sufficiently small to be practical for a surgical instrument where good visibility of the cutting edge is required.
Materials suitable for operating as the working fluid in the thermal distribution means within a temperature range which is satisfactory for hemostatic surgery include sodium, potassium, lithium, cesium, mercury and other materials. The capillary action for transporting the liquid along the chamber wall from areas of condensation to areas of vaporization may be supported by such liquid transport means as screen mesh structures, sintered fibers, porous surfaces adjacent to the interior surface of the chamber, or by fine grooving of the chamber wall. The liquid transport means also provides for separation of liquid and vapor flow, thereby minimizing the entrainment of condensed liquid within countercurrent flow of vapor.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side view of one embodiment of the hemostatic scalpel according to the present invention;
FIG. 2 is an end sectional view of the scalpel of FIG. 1;
FIG. 3 is a side view of another embodiment of a hemostatic scalpel according to the present invention; and
FIG. 4 is an end sectional view of the embodiment of a hemostatic scalpel according to FIG. 3.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to FIGS. 1 and 2, there is illustrated one embodiment of the present invention in which blade portion 1 that is made of a thermally-conducting material may be attached to the extension 11 of handle portion 10 to form the surgical instrument. Facets 2 are formed along the length of the lower border of blade 1 to establish the cutting edge 3 of the instrument. The extension 11 of handle portion 10 includes the thermal distribution means 20, the heater means 8, and the thermal insulating means 12. The heater means 8 is disposed contiguous to and in good thermal contact with the upper circumference of chamber wall 21 of the thermal distribution means 20 throughout its length, and thermal insulating means 12 is disposed over the heater means 8. The lowermost circumference of chamber wall 21 is in close mechanical and thermal contact with the cutting portion of blade 1.
Chamber wall 21 forms a fluid-tight container of the thermal distribution means 20 which includes liquid transport means 22 disposed in both circumferential and longitudinal contiguity to chamber wall 21. The liquid transport means 22 includes a fine mesh screen, fine grooves or other capillary means which may be of the order of 10 mils wide and 10 mils deep on the inner surface of chamber wall 21 to provide a conduit for the travel of the liquid by capillary action. Other suitable wicks or capillary-action structures may be disposed in both a circumferential and longitudinal direction.
Prior to forming chamber walls 21 into a fluid-tight compartment, a quantity of working fluid is introduced into the thermal distribution means 20 sufficient to saturate the wick-like liquid transport means 22 with the liquid at a selected temperature and pressure. This working fluid may be sodium, potassium, lithium, mercury or cesium. These metals are suitable for operation in the desired temperature range because of their excellent thermal conductivity and their high surface tensions which facilitate their transport by capillary action. Of these, potassium and mercury may be preferred because they offer the highest heat transport capacity at lower operating temperatures.
Heater means 8 in the embodiment shown in an electrical resistance heater consisting of electrically insulated high resistance conductors disposed in a suitable pattern in direct thermal contact with the outside surface of the upper circumference of chamber wall 21, or the inside surface of a high-conductivity, high-emissivity material, which in turn is in good mechanical and thermal contact with chamber wall 21. Heater means 8 is energized by the heater power source 13 which is activated by closure of switch 31 in handle 10, under the control of the operating surgeon. A temperature sensor 14 disposed upon and in good thermal contact with chamber wall 21 monitors the temperature of the external surface of the thermal distribution means, preferably in its lower circumference, and produces a representative control signal on line 15 for selectively altering the output of power source 13 in a conventional manner when activated by switch 31 as the temperature of the thermal distribution means 20 approaches a preselected temperature. Alternatively, a pressure sensor means 14 can be disposed to monitor the pressure within the chamber 21 of the thermal distribution means 20 to alter the power supplied to the heater means 8 from source 13 in a manner similar to the one described above with reference to a temperature transducer.
Upon activation of switch 31, the source 13 supplies power to the heater means 8 which thus heats the upper regions of the chamber walls 21. This heating of the chamber wall 21 vaporizes some portion of the working fluid within the chamber of the thermal distribution means 20. The heated vapor rapidly distributes heat over the entire inner surface of the chamber which, in turn, heats the cutting edge portion 1 of the blade. As the temperature of the chamber and, hence, of the cutting edge approaches the desired operating temperature, as monitored by sensor 14, the power source 13 delivers progressively less power merely to maintain the cutting edge at the preselected temperature with the scalpel in the air, an operating condition for which the heat losses are minimal.
As the blade 1 is manipulated to incise tissues, heat losses will increase substantially from the portions of the blade which contact the tissue being cut, thus cooling such portions of the blade and the portions of the chamber wall 21 in thermal contact therewith. Vapor in this region of the chamber of the thermal distribution means 20 will condense upon the cooled region of chamber wall 21, thereby liberating the latent heat of vaporization and selectively heating such cooled portions of the chamber wall 21 that are thermally coupled to the overlying cooled regions of the blade 1. The pressure will decrease in the regions of the chamber where the walls 21 are cooled. Vapor from other regions of the chamber adjacent the heater means 8 will move axially and laterally along the vapor channel that is formed within the central region of the chamber 21 in response to the pressure gradients that are established toward the area of condensation. Heating of locally-cooled regions of the chamber walls (and of the blade 1) by condensation of vapor will continue in this manner as long as cooling by heat loss in such regions continues. The working fluid which is thus condensed in locally-cooled regions is transported to regions of the chamber that are adjacent the heater means 8 by capillary action of the mesh screen 22 (or other capillary structure) where it is again vaporized. Decreases in the average temperature or pressure within the chamber of the thermal distribution means 20, as sensed by either a thermal or pressure sensor 14, controls the power source 13 to increase the power supplied to the heater means 8. Increased heating thus accelerates the rate of vaporization of the working fluid. Thus, vaporized fluid travels along the vapor channel to cooler regions of the chamber 21 where it is condensed and transported by capillary action from the region of condensation back to the regions of vaporization in a continuous manner.
The thermal cycle may be considered as follows:
Vaporization of the working fluid stores thermal energy in the vapor which is then transported by pressure gradients to cooler regions where the vapor condenses and gives up substantially the stored thermal energy. The condensed liquid is then transported by capillary action back to regions that are depleted of liquid due to heating and vaporization.
It should be noted that because the heater means 8 is disposed along the entire length of the thermal distribution means 20, the distances can be made small between regions of thermal distribution means 20 that are adjacent the heater means 8 (i.e., upper circumference of chamber wall 21) and regions of the thermal distribution means 20 that are adjacent the blade 1 (i.e., lower circumferences of chamber wall 21). Because the regions of the thermal distribution means 20 and the heater means 8 adjacent thereto are thermally insulated, the heat transfer is predominantly restricted to the course from the heater means 8 to the blade 1 via the thermal distribution means 20 operating in the manner previously described. The surface temperature of handle 10 and the extension 11 may therefore be maintained comfortably low.
An additional equivalent thermal mass may be provided by including in the thermal distribution means 20 a portion 36 of chamber 21 located remotely from the cutting edge 3 of blade 1 (preferably, in the handle portion 10 or in the extension 11 thereof) which has a residual volume in excess of the volume of the portion of chamber 21 that is in mechanical contact with blade 1. Instead of the chamber 21 terminating at the proximal end 33, the chamber 21 may thus extend optionally to include the residual chamber 36. Similarly, the wick-like structure 22 may also extend into the residual chamber 26. This residual chamber 36, containing a relative abundance of working fluid in liquid and vapor state at the operating temperature, introduces additional thermal inertia in the system.
Referring now to FIGS. 3 and 4, there is illustrated another embodiment of the present invention in which the heating means 38 is disposed contiguous the cutting edge 33 of the blade 32 which, in turn, is in good thermal contact with the lower portion of the chamber 35 of the thermal distribution means 37. Thermal insulating means 39 is positioned along the length of the cutting edge 33 of the blade 32 about the upper portion of the chamber 35. The heating means 38 is connected to receive electrical power from supply 47 which, in turn, may be controlled in response to thermal or pressure transducer 49 in a manner as previously described.
In operation, the cutting edge of the surgical instrument according to this embodiment is cooled in the regions thereof which contact tissue being cut. The heat furnished to such cooled regions by the heating means 38 located thereat is supplemented by the latent heat of vaporization which is released in such cooled regions from the vapor within the chamber 35 that condenses on the chamber walls contiguous to the cooled regions of the blade. This tends to maintain the temperature more uniform along the length of the cutting edge 33 as regions thereof are selectively cooled upon contact with tissue being cut. A resulting decrease in the average temperature or pressure within the thermal distribution means 37 is sensed by the transducer 49 to increase the applied power from source 47 to maintain the cutting edge 33 substantially isothermal during surgical manipulation thereof through tissue.
Where it is desirable to enhance the isothermal operating characteristics of the present invention, a cooling means and additional heating means may optionally be added to the embodiments of FIGS. 1-4 in mechanical and thermal coupling to the thermal distribution means. For example, cooling and heating means may be disposed about the portion of the chamber which is disposed within the handle for convenient operation. Cooling means may be provided by such conventional techniques as controlled release of a compressed gas such as nitrogen or carbon dioxide in heat-transferring relationship to the walls of the chamber. Heating means may be provided by including another electrical heater thermally coupled to the proximal end of the chamber and by operating such heater via control of the electrical power supplied thereto to maintain the thermal distribution means within the desired operating temperature range. Both the cooling means and the heating means may thus be controlled simultaneously and in thermal opposition (for example, in response to a control signal produced by a temperature or pressure transducer that is coupled to the chamber of the thermal distribution means 20 or 27) in order to provide enhanced regulation of the temperature of the cutting edge. | The temperature of the cutting edge of a surgical cutting instrument is maintained within a preselected temperature range for surgical cutting and simultaneous hemostasis by conducting heat from a thermal distributing means that is disposed along the cutting edge of the instrument. The thermal distributing means selectively heats regions of the cutting edge that are locally cooled by the tissue contact of surgical cutting by condensation in the regions of the cooled edge of previously evaporated fluids, with concomitant release of the heat previously absorbed upon evaporation of the fluid. | 0 |
FIELD OF THE INVENTION
The present invention relates to a document image scanner, and more particularly, to an improved image scanner for extracting the target text and other pattern information without hindrance from the background brightness of the document.
DESCRIPTION OF THE PRIOR ART
Image scanners have come into widespread use as a data input means, but if their use is to increase further they have to be able to scan text and other pattern information with greater precision, speed and economic efficiency. To achieve this, with the exception of certain areas of application, such scanners now store, transmit and print the scanned information after it has been binarized.
However, the documents that have to be scanned are varied. In many cases the information may be written on dark-colored paper, or the documents contain extraneous background information such as discolored areas in the case of a copy of a document that has been copied many times. Thus, it is necessary for an image scanner to be not only able to scan a document image, but also to be able to accurately extract the target textual information or the like without being affected by background brightness or noise information.
Because of this, usually the image elements (pixels) are binarized by obtaining the difference between the brightness (intensity) of each pixel and the average intensity of the surrounding pixels, and the binarized data is then used to extract the requisite image data patterns from the background.
In the prior art, convolution is used to obtain the average intensity of the surrounding pixels. A prescribed number of pixels around the pixel of interest are selected and the product of each of these pixels and a window function is obtained, and the value produced by combining these products is then taken as the average intensity around the pixel of interest.
However, as shown by FIG. 1, applying convolution to just a small number of pixels in a small area emphasizes background noise, preventing the image pattern information of interest being extracted with adequate effectiveness. To enable the object information patterns to be effectively extracted, it is necessary to apply convolution to a larger expanse, for example forty or more pixels. As shown by FIG. 2, applying convolution to such a number of pixels makes it possible to suppress background noise and emphasize the patterns of interest on the document.
Unfortunately, the large numbers of multipliers and adders required to perform convolution with a large number of pixels makes the system large and complex, increasing the cost and making it difficult to attain high operating speeds.
SUMMARY OF THE INVENTION
An object of the present invention is therefore to provide an image scanner that is able to efficiently extract textual and other information of interest on a document at high speed with a relatively simple circuit arrangement that provides an image processing performance equal to that obtained by applying convolution to a large number of pixels.
In accordance with the present invention, this and other objects are attained by an image scanner comprising:
an image sensor for receiving light reflected from or transmitted by a document and converting the light into a series of signals representing the light intensity for a plurality of image pixels;
a rounder operatively connected to said image sensor for grouping respective signals for predetermined adjacent image pixels to form a predetermined series of pseudo pixels surrounding a predetermined image pixel and calculating an average light intensity value for each pseudo pixel;
a convolution integrator operatively connected to said rounder for performing convolution operations on the average light intensity value for each pseudo pixel and generating an output signal therefrom; and
a subtracter operatively connected to said image sensor and said convolution integrator for calculating the difference between the output signal of the convolution integrator and the light intensity value of the predetermined image pixel.
Thus, in accordance with this invention, the pixels around the pixel of interest are divided into a number of groups, the average intensity of each group is obtained, and each group is regarded as a pseudo pixel for convolution purposes to thereby obtain the average intensity of the pixels surrounding the pixel of interest. This is then taken as the background intensity, and by then obtaining the difference between this background intensity and the intensity of the pixel of interest, the target text and other pattern information can be extracted.
Further features of the invention, its nature and various advantages will become more apparent from the accompanying drawings and following detailed description of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1 and 2 are diagrams showing the results obtained by scanning a document by several methods of the prior art.
FIG. 3 is a schematic diagram of an image scanner according to the present invention.
FIG. 4 is a schematic diagram showing details of the clock control circuit of the image scanner as shown in FIG. 3.
FIG. 5 is timing diagram of the clocks of the clock control circuit as shown in FIG. 4.
FIG. 6 is a schematic diagram showing details of the rounding circuit of the image scanner as shown in FIG. 3.
FIG. 7 is diagram showing the locations of pixels scanned from the document using the image scanner as shown in FIG. 3.
FIG. 8 is a schematic diagram showing details of the convolution integrator circuit used in the image scanner as shown in FIG. 3.
FIG. 9 is a diagram showing the results obtained by scanning a document using the image scanner as shown in FIG. 3.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 3 shows the principal parts of an embodiment of the image scanner 10 according to the present invention. In the scanner 10, a light source 12 illuminates a document 11 moving at a constant speed in a direction indicated by an arrow S. The pattern of alphanumeric characters and other information on the document 11 thus illuminated by the light source 12 is focussed by an optical system 13 including lenses, optical filters and the like, to thereby form the image on a one-dimensional image sensor 14 comprising a large number of small photosensors of a predetermined size. The one-dimensional image sensor 14 photosensors output on signal line 16 a stream of analog image signals corresponding to each respective pixel, in time with a pixel clock (VCLK) signal on line 15. The image signals are input to an analog/digital (A/D) converter 18. The generation of the image signals of each scanning line proceeds in the direction indicated by arrow M.
The pixel clock signal is provided to two lines that go to a clock control circuit 19 and a rounding circuit 21, respectfully. For each scanning line, the one-dimensional image sensor 14 outputs a line synch clock signal on line 22 to the clock control circuit 19. The output side of the A/D converter 18 is connected to the rounding circuit 21 and to a subtracter 23. The output side of the rounding circuit 21 is connected to the subtracter 23 via a convolution integrator 24.
The clock control circuit 19 supplies to the rounding circuit 21 a 1/4-pixel clock signal on line 26 that is one-quarter the frequency of the pixel clock signal on line 15, and also supplies to the rounding circuit 21 and convolution integrator 24 a 1/16-pixel clock signal on line 27 produced by extending the 1/4-pixel clock signal 26 over four scanning lines. Details of the waveforms of these clock signals are provided below.
The operation of the image scanner 10 thus configured will now be described. When the pattern of alphanumeric characters and other information on the document 11 thus illuminated by the light source 12 is focussed by the optical system 13 to form an image on the photosensors of the one-dimensional image sensor 14, the photosensors output a stream of image signals on line 16 that correspond to the intensity of the received light. On completion of the output of each line of image signals from the image sensors, the document 11 is moved by an amount corresponding to one line in the direction of the arrow S. The one line referred to here corresponds to the scanning resolution of the one-dimensional image sensor 14. This is repeated for the ensuing lines, with the one-dimensional image sensor's photosensors producing a stream of image signals corresponding to each of the pixels of the document 11.
The image signals on signal line 16 output by the one-dimensional image sensor 14 are converted to digital image signals on signal line 28 by the A/D converter 18, and are input to the subtracter 23 and rounding circuit 21. The clock control circuit 19 generates the 1/4-pixel clock signal and the 1/16-pixel clock signal, from the pixel clock signal and line synch clock signal on signal line 22 output by the one-dimensional image sensor 14.
FIG. 4 shows details of the clock control circuit 19. This circuit is equipped with a pair of base-4 counters 31 and 32. The first base-4 counter 31 counts the pixel clock pulses (A) as shown in FIG. 5 and inputs the count value to a first AND circuit 33. The second base-4 counter 32 counts the line synch clock pulses and inputs the count value to a second AND circuit 34. A reference value "3" is input to this AND circuit 34, and when the count from each base-4 counter 31, 32 reaches this reference count "3", a High signal is applied to one of the input terminals of the third and forth AND circuits 35 and 36 respectively.
The pixel clock signal VCLK on line 15 connects to the other input terminal of the third AND circuit 35, and the output of the third AND circuit 35 goes to the other input of the forth AND circuit 36. As shown in FIG. 5, when the output of the first AND circuit 33 goes High, the gate of the third AND circuit 35 opens to output the 1/4-pixel clock signal (B) that is one-quarter of the pixel clock frequency (A). When the output of the first AND circuit 34 goes High, the gate of the forth AND circuit 36 opens to output the 1/4-pixel clock signal obtained by extending the 1/4-pixel clock to every fourth scan line (C). The 1/4-pixel clock signal is input to the rounding circuit 21, and the 1/16-pixel clock signal is input to the rounding circuit 21 and convolution integrator 24.
FIG. 6 shows details of the rounding circuit 21. This circuit is comprised of a 4-pixel totalling section 41 that produces a running pixel total every four pixels of a line, and a 4-line pixel totalling section 42 that uses the output of the 4-pixel totalling section 41 to produce a running total of the pixel count per four lines.
The image signals on signal line 28 digitized by the A/D converter 18 go to one of the input terminals of an adder 43 provided in the 4-pixel totalling section 41. The output side of the adder 43 is divided into two by means of a first register 44, and the other input terminal of the adder 43 and the input terminal of a second register 45 are connected. The output side of the second register 45 is connected to the 4-line pixel totalling section 42.
Also input to the 4-pixel totalling section 41 are the pixel clock signal from signal line 15 from the one-dimensional image sensor 14, which is input via clock terminal C of the first register 44, and the 1/4-pixel clock signal from the clock control circuit 19, which is input to the delay circuit (DLY) 46. The 1/4-pixel clock, which is divided, is also input to the 4-line pixel totalling section 42. The output side of the delay circuit 46 is divided, with one side being connected directly to the clock terminal C of the second register 45 and the other side being connected to the reset terminal R of the first register 44 via a delay circuit 47.
The 4-line pixel totalling section 42 is provided with an adder 51, one of the input terminals of which is connected with the output side of the second register 45 of the 4-pixel totalling section 41. The output side of the adder 51, divided by means of a first line memory 52, is connected to the other input terminal of adder 51 and to a second line memory 53. The 1/4-pixel clock signal from the 4-pixel totalling section 41 is also input to the clock terminal C of the first line memory 52. Assuming that one primary scan by the one-dimensional image sensor 14 scans 4N pixels, the first and second line memories are able to hold the data of one-fourth that many pixels, i.e.. N pixels.
The 1/16-pixel clock output by the clock control circuit 19 is input to the 4-line pixel totalling section 42. This 1/16-pixel clock 27 is divided, being input to a delay circuit 55 and a base-N counter 56. The divided output line of the delay circuit 55 is connected to clock terminal C of the second line memory 53 and to one of the input terminals of an AND circuit 58. The output side of the base-N counter 56 also is connected to one of the input terminals of the AND circuit 57. A reference value "N" is input to the other input terminal of the AND circuit 57. A High signal is output from the AND circuit 57 when the input from the base-N counter 56 matches the reference value "N". This signal is input to the other input terminal of AND circuit 58, the output of which is input, via a delay circuit 59, to the reset terminal R of the first line memory 52. The second line memory 53 outputs 4-line pixel total data 63.
The operation of the rounding circuit 21 as used in this arrangement will now be described. The image signal input from the A/D converter 18 in time with the pixel clock on signal line 15 is added to the first register 44 output by the adder 43. With the output on signal line 48 being "0" in the initial state, the image signal on signal line 28 input to the adder 43 is latched in the first register 44, using the pixel clock signal. The second image signal input at the next pixel clock signal pulse is added to the output of the first register 44 by the adder 43, and the result is latched in the first register 44, using the pixel clock signal. In the same way the third and fourth image signals are added and placed in the first register 44.
The 1/4-pixel clock signal (FIG. 5 (B)) input from the clock control circuit 19 is given a prescribed time delay by the delay circuit 46 and applied to the clock input terminal C of the second register 45. At the input of each of these clock pulses, the image signal data total for four pixels (hereinafter also referred to as "4-pixel total data") stored in the first register 44 is read out and latched in the second register 45. Then, after the application of a set time delay by delay circuit 47, the first register 44 is reset to the initial state by the application of a clock to the reset terminal R of the first register 44.
FIG. 7 shows pixels scanned by the one-dimensional image sensor 14. In the drawing, the circles represent individual pixels, with scanning proceeding sequentially in the primary scanning direction M and being repeated in the secondary scanning direction S. The image signal total for four pixels (X=0), for example, here represented by the solid black circles, is calculated by the 4-pixel totalling section 41, stored in the second register 45 and output to the 4-line pixel totalling section 42. This same procedure is applied for each group of four pixels, so that for one line of pixels (X=0 to N-1) 4-pixel total data for N pixels is produced.
The 1/4-pixel clock signal on signal line 26 synchronizes the input of 4-pixel- total data on signal line 61 to the adder 51 of the 4-line pixel totalling section 42 and is added to the output on signal line 62 of the first line memory 52. In the initial state the contents of the addresses [0] to [N-1] of the first line memory 52 are each "0", so the output 62 is also "0". Therefore, the 4-pixel total data 61 input to the adder 51 is written into the first address [0] of the first line memory 52, at a timing provided by the 1/4-pixel clock signal.
The second 4-pixel total data on signal line 61 (X=1 in FIG. 7) input at the next 1/4-pixel clock pulse is added by the adder 51 to the "0" in the second address location of the first line memory 52. The same process is continued as the third to the N-1 items of 4-pixel total data are stored in the corresponding addresses of the first line memory 52. For the next primary scanning line, also, the 4-pixel total data information is input and combined with the information in the corresponding addresses of the first line memory 52.
When the accumulated pixel total data for the first to the fourth lines has thus been placed in the first line memory 52, the 1/16-pixel clock signal (FIG. 5 (C)) is given a set time delay by the delay circuit 55 and the resultant 1/16-pixel clock signal on signal line 27' is input to the clock terminal C of second line memory 53. As a result, the content of the first line memory 52 address [0] gets written into the corresponding address of the second line memory 53. The 4-line pixel total data that is written into memory at this point is the 16-pixel total of pixel group (X, Y)=(0, 0) of FIG. 7.
In the same way, total values for the sixteen pixels of each of the pixel groups (X, Y)=(1, 0) to (N-1, 0) in FIG. 7 are placed sequentially into second line memory 53 addresses [1] to [N-1] in accordance with the timing of the 1/16-pixel clock signal on signal line 27. When this has been completed, the contents of the first line memory 52 are reset by a reset signal output by the delay circuit 59 to prepare for the arrival of 4-line pixel total data of the next (X, Y)=(0, 1) pixel group.
The 4-line total data for N pixels thus stored in the second line memory 53 is then divided by the pixel total of sixteen per group by a divider (not shown) and the result is input to the convolution integrator 24. This division by sixteen is done by discarding the least-significant four bits of the 4-line pixel total data. The pixel data average for each of the 16-pixel groups of FIG. 7 (hereinafter referred to as the "16-pixel-average data") is thus obtained and input to the convolution integrator 24.
FIG. 8 shows details of part of the convolution integrator 24. This circuit is provided with a series of five registers 71 to 75. The 1/16-pixel clock signal on signal line 27 is input to the clock terminal of each of these registers. The output side of each of the registers is connected to an input terminal of corresponding multipliers 76 to 80. Sequence data items W0 to W4, termed a window function, are input to the other input terminal of the corresponding multipliers 76 to 80. This window function determines the transmission characteristics of a filter, and is set to the particular value needed to attain an objective.
The output sides of multipliers 76 and 77 are connected to a first adder 81 and the output sides of multipliers 78 and 79 are connected to a second adder 82. The output sides of the first and second adders 81, 82 are connected to a third adder 83, the output side of which is connected to one of the input terminals of a fourth adder 84. The other input terminal of the fourth adder 84 is connected to the output side of multiplier 80. The convolution integrator 24 is provided with five sets of this circuit arrangement.
The 4-line pixel total data 63 from the second line memory 53 of the rounding circuit 21 is input sequentially, synchronized by the 1/16-pixel clock signal, and is then given a 1-line delay (amounting to N pixels) by means of a line delay buffer (not shown) and input to the above respective five sets of circuits as the 16-pixel-average data for five lines (in FIG. 7, Y=0 to 4). Convolution is thus performed with respect to the 16-pixel-average data for five lines (FIG. 7, Y=0 to 4).
The following convolution operation is performed with respect to each line. The 16-pixel-average data input from the rounding circuit 21 is sequentially shifted to registers 71 to 75, and the multipliers 76 to 80 are then used to multiply the output of each of these registers by window function sequence data items W0 to W4, and the series of adders 81-84 are then used to obtain the sum 87 of the products.
The same processing is performed with the other four sets of circuits. The outputs of these circuits are added to each other by means of other adding circuits (not shown). Other multipliers (not shown) are used to multiply the outputs thus produced by a prescribed coefficient, and the resulting output is input to the subtracter 23 (FIG. 3) as data on signal line 85 indicating the average intensity of the surrounding pixels. This data is obtained as the result of a convolution operation in which the 400 pixels within the region 86 (indicated in FIG. 7 by the thick line) are treated as 25 pseudo pixels.
The difference between the data from the convolution integrator 24 and the image signal input directly from the A/D converter 18 is obtained by the subtracter 23. If this difference is above a certain level, it is judged that the pixel of interest is part of an alphanumeric character or symbol image pattern, and the following processing is performed.
FIG. 9 (C) was obtained by scanning a document with the image scanner 10 according to this embodiment of the invention. With the present invention it is possible to obtain an image quality that is substantially the same as or better than the quality of the example of FIG. 2. However, FIG. 2 is the result of performing convolution with respect to forty or more pixels, while FIG. 3 is the result of a convolution operation in which the 25-pixel groups of FIG. 7 are each regarded as a pseudo pixel, and these 25 pseudo pixels contain 400 pixels. In actual fact, therefore, it is possible to better suppress background noise because it is possible to obtain background intensity information over a larger area.
In the invention as described in terms of the above embodiment, rounding circuit 21 is used to obtain the average value after obtaining the total of the 16 pixels of each pixel group shown in FIG. 7. At the point at which pixels are totalled every four pixels along the primary scanning lines, after the least-significant two bits of the total data have been discarded to obtain the average value per four pixels, a four-line total is compiled. The least significant two bits of the four-line total are discarded to produce an average value per sixteen pixels.
In this embodiment of the invention, for each pixel of interest image data showing the average intensity of five 16-pixel pixel groups in both X and Y directions is extracted (FIG. 7) and convolution is performed with respect to this total of 25 data items. This is not however limitative; convolution may instead be performed with respect to a total of four data items, two in each of the X and Y directions. In this case the convolution circuit arrangement could be further simplified and the average intensity of 64 (i.e. 16×4) pixels around the pixel of interest obtained. | An image scanner that can extract the information of interest from a document at high speed, using a relatively small-scale circuit arrangement that provides an image processing performance equal to that obtained by applying convolution to a larger number of pixels. Light reflecting from the document is converted to electrical image signals by a one-dimensional image sensor. After these image signals have been digitized by an A/D converter, they are input to an adder. A portion of the digitized signals is input to a rounding circuit in which the average intensity of a pixel unit, each comprised of a prescribed number of pixel groups, is calculated. These units are treated as pseudo pixels on which convolution is performed by a convolution integrator. A subtracter is then used to obtain the difference between signals input from the A/D converter and signals output by the convolution integrator. This is then used to obtain the difference between the intensity of the pixel of interest and the average intensity of the prescribed number of surrounding pixels to effectively distinguish alphanumeric characters and other such information, from the background. | 7 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a power tool including a housing, an output member projecting from the housing, a drive located in the housing for rotating the output member about an axis, and a slip clutch for transmitting torque from the drive to the output member. The slip clutch has a plurality of clutch elements retained against rotation relative to the housing, a control element having a respective plurality of counter-clutch elements cooperating with the plurality of clutch elements, and a plurality of separate spring elements for preloading the clutch elements against the counter-clutch elements of the control element. Thereby, the control element is retained against rotation upon application of the torque thereto until threshold of the torque is reached. A rotatable adjustment element adjusts the preload applied by the spring elements.
2. Description of the Prior Art
In the power tools of the type described above, at a certain resistance torque applied to the output member, transmission of a driving torque, which is produced by the tool drive, to the output member is interrupted in order to prevent any damage. In this power tool, the use of a plurality of separate spring elements insures retaining of a uniform spring characteristic during the service life of the tool to a most possible extent. Thereby, the torque transmission, at a predetermined threshold of the torque, is always interrupted at substantially the same actual torque during the service life of the power tool.
European Patent EP 0 613 758 B1 discloses a power tool with a clutch mechanism with a plurality of helical springs the first ends of which applies pressure to a spherical clutch element, and the second ends of which are supported against a clutch ring. For adjusting the preload against the clutch element, the axial position of the clutch ring is adjusted by rotating the clutch ring. The helical springs project in bores formed in the housing and are associated with respective clutch elements.
The drawback of the known clutch mechanism consists in the large number of separate elements, which increases manufacturing and assembly costs.
Accordingly, an object of the present invention is to provide a power tool in which the drawbacks of the known power tool is eliminated.
Another object of the present invention is to provide a clutch for a power tool and having a stable spring characteristic at a simple construction of the clutch.
SUMMARY OF THE INVENTION
These and other objects of the present invention which will become apparent hereinafter, are achieved by providing a common support element for supporting the spring elements and movable relative to the housing. This permits to handle all of the spring elements together, independently of the tool housing. This provides, on one hand, for a simple assembly, with the spring elements and the common support element forming a sub-assembly produced separately from the remaining portion of the power tool. On the other hand, in the mounted condition, the spring elements can be associated with a member which is not fixedly secured to the housing or forms a part thereof. This, e.g., provides for a constructively simple approach to the adjustment of the preload applied by the clutch elements.
According to a particularly advantageous embodiment of the present invention, the support element is formed as a guide frame rotatable relative to the housing by the control element. Thereby, the spring elements are displaced together with the adjustment element when it is adjusted relative to the housing, whereby a constructively simple adjustment of the preload of the spring elements became possible.
Advantageously, the guide frame has first and second guide parts displaceable relative to each other in the axial direction, and the spring elements are supported at one of their opposite ends against the first guide part and at another of their opposite ends against the second guide part. Thereby, the spring elements are located in a closed member the axial extent of which, however, can be changed in order to adjust the preload applied by the spring elements to different values.
Advantageously, there is provided an end position of the two parts in which the first guide part abut, in the axial direction, the second guide part. Thereby, the slip clutch can be locked, if needed, to prevent, in certain applications, an undesirable interruption in transmission of a torque from the drive to the driven member.
Advantageously, the first and second guide parts are formlockingly connected with each other for joint rotation in a rotational direction. Thereby, spring elements can be used which have a smaller stiffness in a direction transverse to the axial direction, such as helical springs. The formlocking, in the rotational direction, connection between the two parts insures that no side deviation or tilting of spring elements takes place during rotation of the two parts.
Further, to provide for a relative displacement of the first and second guide parts, one of the first and second guide parts is provided with axially extending guide webs and another of the first and second guide parts is provided with complementary, axially extending, guide receptacles. However, the guide webs can be provided only in one part or in both parts, with the receptacles being provided in another part or, likewise, both parts.
In a particularly advantageous embodiment of the present invention, an intermediate disc, which is displaceable in an axial direction but is retainable against rotation, is provided between the support element and the clutch elements. This insures that only axial compression stresses are applied to the clutch elements. Frictional stresses, which are produced by rotation of the support element, are transmitted to the intermediate disc that is supported against the tool housing in the rotational direction.
It is advantageous when the support element and the adjustment element are formlockingly connected with each other for joint rotation in a rotational direction. This provides for a direct force transmission from the adjustment element to the support element, so that the tool construction can be simplified. Simultaneously, in this way, upon adjustment of the adjustment element, the preload is indirectly adjusted.
The novel features of the present invention which are considered as characteristic for the invention, are set forth in the appended claims. The invention itself, however, both as to its construction and its mode of operation, together with additional advantages and objects thereof, will be best understood from the following detailed description of preferred embodiment, when read with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
The drawings show:
FIG. 1 a partially cross-sectional side view of a power tool according to the present invention; and
FIG. 2 an exploded perspective view of a spring device.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
An electrically driven power tool 2 according to the invention, which is shown in FIG. 1 , is formed, e.g., as a screw-driving tool. The power tool 2 has a housing 4 in which a tool drive, which is generally designated with reference numeral 6 is located. The drive 6 applies a torque to a spindle-shaped driven member 8 . On the driven member 8 , there is supported a working tool receptacle 10 such as, e.g., a drill chuck which is rotated by the drive 6 about an axis A. The drive 6 includes a motor 12 and a transmission mechanism 14 both located in a drive housing 16 fixedly secured in the tool housing 4 .
The drive 6 further has a control element 18 , e.g., in form of a planetary gear ring that cooperates with a schematically shown gear means 20 , e.g., in form of a stage of planetary gears.
Between the control element 18 and the drive housing 16 , there is provided a slip clutch that is generally designated with a reference numeral 22 . The clutch 22 has a plurality of clutch elements 24 , e.g., in form of pins, balls, or their combination. The clutch elements 24 are preloaded in the axial direction against the control element 18 and are axially displaceable. However, the clutch elements 24 are retained against rotation in receiving bores 25 of the drive housing 16 . The preload of the clutch elements 24 is effected with a spring device 26 that includes a plurality of spring elements 28 in form of helical springs.
The spring device 26 is formed as a pre-assembled unit and includes a support element 30 on which all of the spring elements 28 are supported parallel to each other. The support element 30 is formed as a two-part guide frame having first guide part 32 and second guide part 34 axially displaceable relatively to each other but without a possibility of rotation to each other. The extending parallel to each other, spring elements 28 are supported at their respective opposite ends against the first guide part 32 and at the second guide part 34 .
The first guide part 32 connects the support element 30 , in a manner not shown in detail, with a sleeve-shaped adjustment element 36 for joint rotation in a rotational direction D about an axis A. The adjustment element 36 is rotatably supported on the tool housing 4 and serves for adjusting the preload of the clutch elements 24 with the support element 30 . The preload is applied to the clutch elements 24 by the second guide part 34 via an intermediate disc 38 .
As shown in FIG. 2 , the intermediate disc 38 is formed as an annular disc and is pushed over a neck 40 of the drive housing 16 . Upon the intermediate disc 38 being pushed over the neck 40 , lugs 42 of the intermediate disc 38 , which extend radially inwardly, engage in correspondingly positioned elongate grooves 44 which are formed in the neck 40 and which extend parallel to the axis. This insures an axial displacement of the intermediate disc 38 but prevents rotation of the intermediate disc 38 relative to the drive housing 16 or the tool housing 4 .
The drive housing neck 40 is provided with an outer thread 46 that cooperates with an inner thread 48 provided on the first guide part 32 . Upon rotation of the adjusting element 36 , the spring device 26 , which is connected with the adjusting element 36 via the first guide part 32 , also rotates relative to the drive housing 16 . Due to the cooperation of the outer thread 46 with the inner thread 48 of the first guide part 32 , the first guide part 32 is also displaced axially relative to the drive housing 16 . Thereby, an axial distance between the first and second guide parts 32 , 34 is adjusted. The second guide part 34 is supported at that via the intermediate disc 38 against an end side 50 of the drive housing 16 in which the receiving bores 25 for the clutch elements 24 are formed. Thereby, the preload, which is produced by the spring device 26 , is adjusted by changing the distance between the first and second guide parts 32 and 34 .
With the adjustment of the preload applied by the spring device 26 , a threshold of a torque, which is transmitted from the drive 6 to the driven member 8 is determined. Upon reaching this threshold, the clutch elements 24 are displaced against the adjusted preload out of the counter-clutch elements 51 which are formed, e.g., as pockets in the control element 18 . The clutch element 24 are pushed through the receiving bores 25 , whereby they displace the intermediate disc 38 against the preload of the spring device 26 and disengage from the counter-clutch elements 51 . As a result, the control element 18 rotates relative to the drive housing 16 , so that the transmission of the torque from the drive 6 to the driven member 8 of the transmission mechanism 14 .
As shown in FIG. 2 , the first and second guide parts 32 , 34 have, for positioning of the spring elements 28 , centering cams 52 that are insertable in the spring elements 28 , and receiving means 54 into which the spring elements 28 are partially insertable. Guide webs 56 project from one of the first and second guide plates 32 , 34 in axial direction. The webs 56 cooperate with likewise axial extending guide receptacles 58 to provide for a formlocking connection of the two guide parts 32 , 34 to insure their joint rotation in the rotational direction D, on one hand and, on the other hand, to insure their axial displacement relative to each other. All this insures that the spring elements 28 are deformed only axially.
The axial extension of the guide webs 56 and the guide receptacles 58 are so selected that the guide parts 32 , 34 directly abut each other in an end position, independent of the spring elements 28 , forming a hard stop with respect to each other. In this end position, the clutch elements 24 are secured in their engagement position with the counter-clutch elements 51 . As a result, no interruption in the transmission of the torque takes place when the threshold of the torque is exceeded. This means that in this position the function of the slip clutch 22 is disabled.
Though the present invention was shown and described with references to the preferred embodiment, such is merely illustrative of the present invention and is not to be construed as a limitation thereof and various modifications of the present invention will be apparent to those skilled in the art. It is therefore not intended that the present invention be limited to the disclosed embodiment or details thereof, and the present invention includes all variations and/or alternative embodiments within the spirit and scope of the present invention as defined by the appended claims. | A power tool includes an output member ( 8 ) projecting from the tool housing ( 4 ), a drive ( 6 ) located in the housing for rotating the output member ( 8 ), and a slip clutch ( 22 ) for transmitting torque from the drive ( 6 ) to the output member ( 8 ) and including a plurality of clutch elements ( 24 ) retained against rotation relative to the housing ( 4 ), a plurality of separate spring elements ( 28 ) for adjustable preloading the clutch elements ( 24 ) against the counter-clutch elements ( 51 ) of the control element ( 18 ) for retaining the control element ( 18 ) against rotation upon application of the torque thereto until threshold of the torque is reached, and a common support element for supporting the spring elements and movable relative to the housing ( 4 ). | 1 |
BACKGROUND OF THE INVENTION
This invention relates to a hand-operated home knitting machine, and more particularly to a needle selection mechanism in a hand-operated knitting machine in which needle selection is controlled in accordance with a patterning or needle selection program prepared therefor.
Hand-operated knitting machines on which a knitted fabric having a desired design pattern thereon can be produced are normally provided with needle selection functions which are controlled in accordance with a patterning or needle selection program prepared therefor. Conventionally, a perforated or punched program card or sheet carries a needle selection program in the form of punched holes formed in rows and columns therein. A program reading device which is mounted alongside the needle bed of the knitting machine and has a set of feeler elements reads a row of punched holes of the program card or sheet, and during a sliding movement of the carriage on the needle bed a needle selector member on the carriage selects knitting needles in the needle bed in accordance with the readings of the program by the program reading device. Since such readings of the needle selection program are mechanically transmitted to the needle selector member and the needle selector member mechanically engages with the butts of knitting needles for their selection, considerable noises are produced by the associated parts of the machine. Taking it into consideration that hand-operated home knitting machines are typically used indoors by housewives or young women, it is always required for a hand-operated knitting machine to have, at least, minimized production of noises caused thereby.
SUMMARY OF THE INVENTION
It is, therefore, an object of the present invention to provide a needle selection mechanism in a hand-operated knitting machine by which selection of knitting needles is effected reliably with a minimized production of noises in accordance with a needle selection program provided by a perforated program card or sheet.
According to the present invention, there is provided a needle selection mechanism in a hand-operated knitting machine of the type having a needle bed with a plurality of knitting needles mounted therein and a carriage mounted for longitudinal slidable movement on the needle bed, wherein it comprises a program carrier mounted alongside the needle bed and carrying a patterning program in the form of punched holes arranged in rows and columns thereon, the mechanism further comprising a first drum means having thereon a plurality of settable elements adapted to be set from their initial positions in accordance with a row of the punched holes when the carriage passes the program carrier in a direction, the first drum means being mounted for rotation about an upright shaft fixed on the carriage and having thereon an integral gear adapted to be engaged, at one diametrical position thereof, with a rack provided along the needle bed, the gear being engaged, at the other diametrical position thereof, with a second gear which is integrally attached to a second drum means, the second drum means being rotatable about an inclined shaft fixed on the carriage and having thereon a plurality of settable elements mounted for engagement with the corresponding settable elements on the first drum means to be set thereby from their initial positions in accordance with the settings of the first drum means, the second drum means being operable to select the knitting needles in accordance with the settings of the settable elements thereon during movement of the carriage in the other direction on the needle bed, all the settable elements on the first and second drum means being restored to their initial positions by a clearing means mounted on the carriage after completion of selection of the knitting needles in accordance with the settings on the second drum means.
During a directional movement of the carriage on the needle bed, the first-mentioned gear is rotated in a direction by the rack on the needle bed in a manner in which it rolls on the rack so that the second gear is rotated in the other direction by the first gear as if it rolls on an imaginary line which is in parallel with the rack and tangential to the second gear at a diametrically opposite position thereof to the first gear. Thus, transmission of data for needle selection from the program carrier to the first drum means and then from the first to the second drum means is accomplished during similar rolling engagement between them, thereby minimizing collisions of parts which cause production of noises. Needle selection is effected also with minimized collisions of parts such that, during rotation of the second drum means, those settable elements thereon which are, for example, in their initial positions are successively brought into engagement at their lower sections, with butts of knitting needles aligned very near to the above-mentioned imaginary line to gradually displace or push same forwardly to select them. Thus, production of noises associated with needle selection is minimized in the needle selection mechanism according to the present invention.
Preferably, the clearing means includes a common clearing member mounted for pivotal motion from an initial inoperative position to an operative position in which it is engaged with the settable elements of the first and second drum means in their set positions to restore same to their initial positions. The clearing member may be connected to a cam follower lever so that a pivotal motion in a particular direction brings the clearing member into its operative position. During a directional movement of the carriage on the needle bed, a clearing cam mounted alongside the needle bed and extending over the width of the program carrier is engaged with the cam follower lever to pivot same in the particular direction thereby to hold the clearing member in its operative position during over one complete revolution of both drum means to restore all of the settable elements on both drum means to their initial positions. The cam follower lever is so positioned on the carriage that any given settable element on the first drum means is restored to its initial position before it is brought into register with a corresponding needle selection data on the program carrier to be set in accordance therewith during succeeding rotation of the first drum. The arrangement in which data stored on the first drum means, or in other words, settings of the settable elements thereon are thus maintained uncleared until a point of time directly before the first drum means is set in accordance with fresh needle selection data enables the second drum means to be set correctly even if the carriage is reversed directly after all of the settable elements on the first drum means have just been set afresh. On the contrary, if a clearing member for clearing data on the first drum means is alternatively fixed and always operative so that during rotation of the first drum means in one direction any given settable element on the first drum means is cleared after transmission of its data to the corresponding settable element on the second drum means, such reversal of the carriage as described above would lead to a condition in which substantially one half of the total settable elements on the first drum means are operated by the clearing member before they are brought into cooperation with the settable elements on the second drum means thus without transmission of their data to the latter, thereby leading to erroneous needle selection.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a hand-operated knitting machine incorporating a needle selection mechanism according to the present invention;
FIG. 2 is a detailed plan view, partly broken, showing part of a body of the knitting machine of FIG. 1;
FIG. 3 is a fragmentary plan view of a carriage with its cover removed to show a needle selector unit of the needle selection mechanism;
FIG. 4 is an enlarged vertical sectional view of a program providing device and the carriage taken through a plane which contains axes of two drums of the needle selector unit of FIG. 3;
FIG. 5 is a fragmentary rear view of the carriage;
FIG. 6 is a plan view of another needle selector unit to be paired with the unit shown in FIG. 3; and
FIG. 7 is a bottom view of the carriage showing the cam arrangement thereon.
DETAILED DESCRIPTION OF THE INVENTION
Referring to FIG. 1, the hand-operated knitting machine consists of a machine body 1 having a needle bed 2 located in the substantial front half section thereof. A plurality of knitting needles 32 each having a butt 32a are tricked in the needle bed 2 for individual longitudinal movement therein. A carriage 9 (FIG. 3) is mounted for slidable back and forth movement on the needle bed 2. In the rear half section of the machine body 1, there are disposed, from left to right, a tool receptacle 6 in the form of an elongated tray for receiving therein tools and accessories such as a tappet tool for use with the machine, a program providing device 3 forming part of the needle selection mechanism according to the present invention, a fashioning or knitting width indicator 4 for currently indicating a knitting width, or in other words, the knitting needles 32 to be operated in a current course of knitting, and a row counter 5 for counting the number of rows or courses knitted. Manually operable members such as dials, knobs, push buttons, levers, and the like, for manual control of the program providing device 3, the fashioning indicator 4, and the row counter 5 are also provided suitably on a panel member which covers most part of the rear half section of the machine body 1.
The program providing device 3 has a program carrier 7 removably mounted thereon which is formed as an elongated card or sheet made of paper or a synthetic resin. The program carrier 7 has a pair of rows of perforations 7a (FIG. 3) formed along opposite side edges thereof and carries thereon a patterning or needle selection program in the form of punched holes 7b (FIG. 4) arranged in rows and columns thereon which program generally indicates a unit design or pattern to be repetitively produced on a knitted fabric. The program carrier 7, when set in position on the program device 3, extends along a path partially surrounding a feed roller 3a (FIG. 4) of the program device 3 between a front inlet slit and a rear outlet slit both suitably formed in the panel member on the machine body 1. The program carrier 7 is carried on the feed roller 3a with its perforations 7a engaged with sprockets of a pair of sprocket wheels provided at opposite ends of the feed roller 3a so that upon an incremental angular rotation of the feed roller 3a in a clockwise direction in FIG. 4 it is fed from row to row in a proper direction.
As best seen from FIG. 4, the program device 3 includes a plurality of feeler levers 11 mounted for pivotal motion about a horizontal rod 11a which extends in parallel with the needle bed 2. The feeler levers 11 are normally urged clockwise about the rod 11a individually by fingers of a spring comb 11b to a position shown in full line in FIG. 4. Each feeler lever 11 has a projection or feeler portion 11c adapted to sense a punched hole 7b in the program carrier 7 when the carriage 9 passes over the program device 3.
The program device 3 further includes a cam follower lever or actuator lever 8 (FIGS. 1, 2 and 4) located near the center of the machine body 1. The actuator lever 8 extends forwardly towards the needle bed 2 through an opening suitably formed in a rear upright wall section 2a (FIG. 4) of the needle bed 2. Upon a sliding movement of the carriage 9 on the needle bed, an actuator cam 10 (FIG. 3) mounted on the carriage 9 is engaged with the actuator lever 8 to rock same from a position shown in full line in FIG. 4 to another position shown in phantom line about a pivot pin (not shown) whereby a conventional feed mechanism (not shown) is actuated to angularly rotate the feed roller 3a an increment in the clockwise direction to feed the program carrier 7 thereon from row to row in the proper direction.
The fashioning indicator 4 also includes a cam follower lever or actuator lever 12 located adjacent to the actuator lever 8 of the program device 3 and extending towards the needle bed in a similar manner. Upon sliding movement of the carriage 9, an actuator cam 13 (FIG. 3) mounted thereon is engaged with the actuator lever 12 (FIG. 2) to rock same about a vertical pivot pin to actuate an associated feed mechanism (not shown) which thus rotates a feed roller (not shown) to feed a pattern sheet 14 thereon an increment in a predetermined direction.
The pattern sheet 14 consists of an elongated sheet made of paper or a synthetic resin material and carries thereon a pattern 15 representative of a profile of an article to be knitted, such as of a front part of a garment. The pattern sheet 14, when set in position on the fashioning indicator 4, also extends along a path partially surrounding the feed roller between a front inlet slit and a rear outlet slit both suitably formed in the aformentioned panel member. A scale 14a having thereon a plurality of appropriate graduations (see FIG. 1) is mounted adjacent to the inlet slit and is adapted to indicate, in cooperation with the pattern 15 on the pattern sheet 14, the knitting width for a current course of knitting or, in other words, the number of knitting needles 32 to be operated in a current knitting operation by the carriage 9.
Referring now to FIG. 2, the aforementioned row counter 5 has a drive mechanism including a pinion 16 which is meshed with a rack 18a formed on a connecting rod 17 adjacent one end thereof. Another rack 18b formed on the connecting rod 17 adjacent to the other end therof is meshed with another pinion 19 which is mounted on the aforementioned vertical pivot pin for the actuator lever 12 of the fashioning indicator 4. The row counter 5 is thus linked with the actuator lever 12 of the fashioning indicator 4 so that, upon rocking motion of the actuator lever 12, the row counter 5 is operated thereby to increment its counting values in order to digitally indicate the number of knitted rows or courses counted thereon.
The machine body 1 further has a handle 20 provided substantially at the center of the back wall section thereof. The handle 20 has its opposite ends linked to a pair of mounting pieces 21 by means of connecting rings 22. The mounting pieces 21 are each provided with a vertically extending through hole 23 for removably receiving therein the lower end of a support rod 25 (FIG. 1) to support same in an upright position. One of the two holes 23 is located substantially behind the center of the program providing device 3 while the other hole 23 is located behind the left end of the fashioning indicator 4, as best seen from FIG. 2.
The support rod 25 is slightly bent at its middle portion to provide an upright lower portion and in inclined upper portion. A take-up device 24 is supported on the top of the support rod 25. The take-up device 24 has a pair of conventional take-up springs 24a adapted to engage with yarns 63, 64 to take up slack thereof intermediately between yarn supplies and the carriage 9. Those yarns 63, 64 are supplied to knitting needles 32 in the needle bed 2 through a yarn feeder mounted on the carriage 9 when the carriage 9 is slidably moved on the needle bed 2.
Since there are provided two mounting pieces 21 as described above, the take-up device 24 can be positioned alternatively above the program providing device 3 or above the fashioning indicator 4. In case the take-up device 24 is positioned above the program device 3, the head and tail ends of the program carrier 7 set on the program device 3 are allowed to bear against the support rod 24 in a reclined position so that the operator of the knitting machine can easily and directly observe the patterning or needle selection data on the exposed front part of the program carrier 7. The front part of the program carrier 7 is thus held in an appropriate position without falling forwardly or hitting upon the carriage 9. As the knitting operation proceeds, the rear end of the program carrier 7 having been discharged from the program device 3 bears against the support rod 25 and uprises therealong. Thus, the program carrier 7 is smoothly discharged under the guidance of the support rod 25.
Referring now to FIGS. 3 to 6, the carriage 9 has a generally symmetrical construction relative to the transverse center line thereof, and has a pair of needle selector units 26 mounted adjacent to opposite ends thereof, although there is illustrated only the left-hand side of one of the needle selector units 26 in FIG. 3, the right-hand side needle selector unit 26 being illustrated in FIG. 6 as a separate assembly.
Each needle selector unit 26 includes first and second drums 26a and 26b each having thereon a predetermined number, typically 24, which is same as the number of the aforementioned feeler levers 11 of the program device 3, of settable elements or tiltable levers 27 and 28, respectively. The tiltable levers 27, 28 are disposed in equidistant circumferential positions on the first and second drums 26a, 26b, respectively, such that the distance between two adjacent tiltable levers 27 or 28 is equal to that between two adjacent feeler levers 11 of the program device 3 and also to that between two adjacent knitting needles 32 in the needle bed 2.
The tiltable levers 27 on the first drum 26a are supported at their mid portions for tilting motion about a support ring 27c between a normal position shown in phantom line in FIG. 4 and a tilted position shown in full line in the same figure. Each tiltable lever 27 is provided with an upper projection or input portion 27a and a lower bent lug or output portion 27b. A detent element 43 in the form of a small steel ball which is urged downwardly by a finger of a leaf spring 44 mounted at the top of the first drum 26a acts upon the top end of each tiltable lever 27 to yieldably hold the lever 27 to its normal or tilted position.
The first drum 26a is mounted for rotation about an upright shaft 41 and has a gear 29 attached to the lower end thereof and adapted to be meshed with a rack-like element 30 on the rear upright wall section 2a of the needle bed 2. The gear 29 is meshed, at a diametrically opposite position to the rack-like element 30, with a second gear attached to the lower end of the second drum 26b which is mounted for rotation about an inclined shaft 42. Both shafts 41 and 42 are attached to a support plate 40 mounted on the carriage 9 by means of fastening screws. The support plate 40 is slightly bent at its mid portion so that the front portion thereof extends, together with part of the second drum 26b, l through an opening 9a appropriately formed in the carriage 9 towards the needle bed 2 thereby enabling the tiltable levers 28 on the second drum 26b to act upon the butts 32a of the needles 32 in the needle bed 2.
Each of the tiltable levers 28 is also provided with an upper projection or input portion 28a and a lower bent lug or output portion 28b. Each tiltable lever 28 is further provided at the lower end thereof with a curved extension which is received in a spacing formed between an annular rib 46 provided at the bottom end of a body 45 of the second drum 26b and the rounded top face 47 of the second gear 31 so that it is allowed to tilt about the annular rib 26b between a normal position shown in full line in FIG. 4 and a tilted position shown in phantom line. A detent element 48 in the form of a small steel ball which is urged by a finger of a leaf spring 49 mounted at the top of the second drum 26b acts upon the top end of each tiltable lever 28 to yieldably hold the tiltable lever 28 to either of the normal and tilted positions.
When the carriage 9 is slidingly moved in a direction on the needle bed 2, the gear 29 of the first drum 26a is rotated in one direction about the shaft 41 by the rack-like element 30 and rolls on and along the element 30 while the second gear 31 is rotated by the first gear 29 in the opposite direction about the inclined shaft 42. While the first drum 26a passes over the program device 3 on the machine body 1, the tiltable levers 27 thereon in their normal positions are successively brought into engagement, at the upper projections 27a thereof, with the corresponding feeler levers 11 to push them rearwardly against the urging of the leaf spring 11b whereupon those of the feeler levers 11 which have a feeler element 11c opposed to a punched hole 7b of the program carrier 7 are displaced or pivoted rearwardly to the position shown in phantom line in FIG. 4 with the corresponding tiltable levers 27 being allowed to remain in their normal positions whereas those feeler levers 11 which have a feeler element 11c opposed to an unpunched area of the program carrier 7 are blocked by the same to remain in their normal positions thereby to cause the corresponding tiltable levers 27 to be tilted from the normal to the tilted positions. Thus, during one pass of the first drum 26a by the program device 3, the first drum 26a is set in accordance with the data in an appropriate row of punched holes in the program carrier 7, or in other words, the data in a row are stored mechanically on the first drum 26a at the tiltable levers 27 thereon. Also, appropriate row of punched holes in the program carrier 7, or in other words, the data in a row are stored mechanically on the first drum 26a at the tiltable levers 27 thereon. Also, during one complete revolution of the first drum 26a thus set and the second drum 26b, the tiltable levers 28 in their normal position are successively brought into engagement with, at the upper projections 28a thereof, the corresponding tiltable levers 27 at the lower projections 27b thereof to be set thereby in a similar manner. Thus, the data stored on the first drum 27 are transmitted to and stored mechanically on the second drum 28. In order to ensure the transmission of data from the first to the second drum, there is provided means for blocking the tiltable levers 27 of the first drum 26a from being tilted from the tilted back to the normal positions during engagement thereof with the tiltable levers 28 on the second drum 26b to thereby force the tiltable levers 28 to be tilted to the tilted positions. The blocking means consists of a plate member 50 which is fixed on the support plate 40 (FIG. 3) and overlies the gear 29 of the first drum 26a with an appropriate clearance therebetween. The plate member 50 has an upright wall 50a which extends in an arc concentric with the first drum 26a within the range in which the tiltable levers 27 and 28 are engaged with each other. The wall section 50a of the plate member 50 is located just inside the lower ends of the tiltable levers 27 in their tilted position so as to be engaged thereby to retain same in their tilted position.
It is to be noted that each patterning data stored on the first drum 26a is transmitted from a tiltable lever 27 to a corresponding tiltable lever 28 on the second drum 26b after a half revolution of the first drum 26a. Thus, during one complete revolution of the two drums after the first drum 26a begins to sense the patterning data on the program carrier 7 by way of the feeler levers 11 only the first half of the data, that is, the first 12 data in case of the data carrier 7 which typically has up to 24 patterning data in each data row, are transmitted to the second drum 26b. The remaining data, from the 13th to 24th, are transmitted therefore during a subsequent succeeding half revolution of the drums 26a, 26b. Accordingly, the transmission of all the data from the first to the second drum requires one and a half revolutions of the drums 26a, 26b.
The selector assembly further includes a clearing member 33 which has two cam means or faces 33a and 33b (FIG. 6) provided thereon. The clearing member 33 is supported on a pin 34 for pivotal motion between an operative position (indicated in phantom in FIG. 5) in which the cam faces 33a and 33b are engaged with the tiltable levers 27 and 28 on the first and second drums 26a and 26b, respectively, to restore them to their normal positions thereby to clear the data stored on them and an inoperative position (indicated in full line in FIGS. 3 and 5) inoperative to the drums 26a and 26b.
A cam follower lever 35 is pivotally mounted on a pin 26 fixed at a rear center position of the carriage 9 and has its opposite sides linked to the two clearing members 33 through connecting rods 37. Each connecting rod 37 has one end projected into an arcuate slot formed in the cam follower lever 35 to provide a lost motion connected between the lever 35 and the clearing member 33. The cam follower lever 35 is normally retained in a neutral position by a coil spring 38 which is tensioned between the two connecting rods 37, with its engaging portion 35a projected rearwardly of the carriage 9, to hold the clearing members 33 in their inoperative position.
A clearing cam 39 is fixed beneath the front side of the program device 3 over a distance substantially the same as or rather greater than the length of the array of the feeler levers 11 of the program device 3. Thus, upon a sliding movement of the carriage 9, the clearing cam is engaged by the engaging portion 35a of the cam follower lever 35 to pivot the lever 35 in a clockwise or counterclockwise direction (FIG. 3) against the force of the tension spring 38.
When the cam follower lever 35 is pivoted clockwise during a leftward movement of the carriage 9, only the right one of the connecting rods 37 (FIG. 3) is operated due to the lost motion connection to displace the right-hand clearing member 33 into its operative position. On the other hand, the left-hand connecting rod 37 is operated by counterclockwise rotation of the cam follower lever 35 to displace the left-hand member 33 into its operative position. As the carriage 9 is slid back and forth, the needle selecting operation is performed by that one of the selector units 26 which precedes in reference to the direction of the sliding movement of the carriage 9. Before the other succeeding selector unit 26 reaches the program device 3, the cam follower lever 35 which is located centrally between the two selector units 26 is engaged with the operating cam 39 to pivot in a direction whereby the clearing member 33 of the succeeding selector unit 26 is displaced into its operative position to clear the patterning data stored on both drums 26a and 26b for the preceding course of knitting. After such clearing of the patterning data, fresh patterning data for a next subsequent course of knitting are sensed and transmitted to the succeeding selector unit 26 and stored thereon.
It is to be noted here that the program carrier 7 on the program device 3 is fed from row to row at a suitable point of time during a directional movement of the carriage 9 after the preceding selector unit 26 has left the program device 3 and before the succeeding selector unit 26 is brought into before the succeeding selector unit 26 is brought into cooperation with the program device 3. The actuator lever 8 and the actuator cam 10 are so positioned relative to each other on the machine body 1 and the carriage 9, respectively, to allow the program carrier 7 to be fed at such point of time.
Now, transmission of patterning data is investigated rather more in detail. Let us assume that the program carrier 7 includes up to 24 patterning data in each data row thereof and the carriage 9 has been moved from the left across the program device 3 to the position as shown in FIG. 3 in which the last feeler lever, that is, the 24th feeler lever 11x is engaged with a corresponding tiltable lever 27 on the first drum 26a with data transmitted to the lever 27 therefrom. In the position of the carriage 9, the 24 patterning data have been transmitted to be stored on the first drum 26a while the first half of the data, that is, the 1st to 12th data have been transmitted to the 1st to 12th tiltable levers 28 of the second drum 26b which are positioned on the right-hand half of the second drum 26b since the first and second drums 26a and 26b are rotated counterclockwise and clockwise, respectively, about their axes. The remaining 13th to 24th patterning data which are on the left-hand half of the first drum 26a are not yet transmitted to the second drum 26b. It will be readily understood that a further rightward movement of the carriage 9 which causes a half revolution of the drums 26a and 26b causes the remaining patterning data to be transmitted to be stored on the second drum 26b, which thus has all the patterning data stored thereon. On the contrary, if the carriage 9 is now moved reversely to the left from the position as shown in FIG. 3, the first and second drums 26a and 26b are rotated clockwise and counterclockwise, respectively, and the remaining 13th to 24th patterning data stored on the first drum 26a will be transmitted one after another to the second drum 26b in the latter half of a subsequent one complete revolution of either drum 26a, 26b in the above-identified direction. During such one revolution of the drums 26a, 26b, the feeler levers 11 are again engaged by the tiltable levers 27 on the first drum 26a and sense to transmit the same patterning data to the first drum 26a; the program carrier 7 is fed from row to row during a further leftward movement of the carriage 9. The manner of data transmission in the right-hand selector unit 26 is similar to that as described above with an exception that the arrangement is symetrically relative to the transverse center line of the carriage 9 as described before.
While patterning data are stored afresh on the preceding one of the selector units 26 during each directional movement of the carriage 9 as described above, needle selection is effected by the succeeding one of the selector units 26. FIG. 7 shows a preferred cam arrangement which is suitably adapted for such needle selection system. The cam arrangement also has a generally symmetrical construction relative to the transverse center line of the carriage 9 and includes a front partition wall 58 located in a frontmost position and extending along most of the length of the carriage 9. A fixed center cam 59 is located behind the partition wall 58 at the center of the carriage 9. A pair of second partition walls 56 are located also behind the front partition wall 58 at opposite side of the center cam 59. A knitting cam 55 having an auxiliary cam 54 pivotally mounted thereon is located behind each second partition wall 56. A fixed substantially rectangular cam 53 disposed to provide cam edges askew to the length of the carriage 9 is located outside the second partition wall 56 and the knitting cam 55. The needle selector member, that is, part of the second drum 26b is disposed adjacent and outside the rectangular cam 53. At an outermost position adjacent to either end of the carriage 9 and to either needle selector member 26, a pivotal cam 52 is mounted for pivotal motion about a pivot and is normally urged to engage with an outer extension of a rear partition wall 65 by a torsion spring (not shown). In order to attain a variety of butt paths for knitting various kinds of stitches such as a plain stitch, a tuck stitch, a welt stitch, a fair-isle stitch, a punch lace stitch, and so on, some of the cams and some other cams such as the auxiliary cams 55, knit-in or tuck cams 60, and change-over cams 66, are manually adjustable to preselected positions by means of a known control means including a manually operable member, such as a cam lever, description of which is omitted.
Two typical butt paths X1 and X2 are shown in FIG. 7 which are adapted for a punch lace stitch. Upon movement of the carriage 9 on the needle bed 2, butts 32a of the knitting needles 32 are first guided by a pivotal cam 52 and then selectively separated into two groups by a needle selector member 26. The needle butts 32a in a first group not selected will therefore follow the first butt path X1 while the needle butts in a second group selected will follow the second butt path X2. The first needles 32 are first lowered a little and then raised by the knitting cam 55 beyond the clearing position whereafter they are lowered to an intermediate position at which they are supplied with two yarns such as a yarn 63 and a nylon thread 64 (FIG. 1) fed through first and second eyes 61 and 62 (FIG. 7), respectively, both formed on a yarn feeder mounted on the carriage 9. The first needles 32 are then further lowered by the other knitting cam 55 beyond the knockover position to knit the two yarns 63 and 64 into needle loops. The second needles 32 are first raised beyond the clearing positions further than the first needle 32 and then lowered by the front partition wall 58, the second partition wall 56 and a swing cam 57 mounted pivotally thereon and are supplied with a yarn such as the nylon thread 65 fed through the front eye 62. The first needles 32 are then further lowered by the knitting cam 55 beyond the knock-over position to knit the yarn 57 into needle loops whereafter they are disengaged from the carriage 9 together with the first needles 32. Thus, a row of punch lace stitches can be knitted by a directional movement of the carriage 9 on the needle bed 2.
As seen from FIG. 7, needle butts 32a in the second group follow an arcuate path relative to the carriage 9 which is substantially concentric with the second drum 26b when they are engaged to be displaced by the tiltable levers 28 for their selection. The arcuate path appears due to the fact that the needle butts 32a are pushed forwardly by the lower bent lugs 28b of the tiltable levers 28 of the second drum 26b. In particular, the bent lugs 28b have a semicircular configuration at its outer half section, as seen from FIG. 7. During rotation of the drum 26b, a tiltable lever 28 in its normal position is engaged, at an outer semicircular portion of its lower bent lug 28b, with a butt 32 of a knitting needle which is in a longitudinal position as shown in phantom in FIG. 4, and gradually pushed it forwardly to a position in full line in FIG. 4 as the center of the arc of the lower bent lug 28b are substantially held aligned with the needle butt 32a. Thus, the needle butt 32a actually moves along a portion of the arc of the bent lug 28b relative to each other while it is pushed forwardly. A tiltable lever 28 on the second drum 26a which is in its tilted position as shown in phantom in FIG. 4 has its lower bent lug 28b positioned above a needle butt 32a in its phantom position so that it is not engaged with the needle butt 32a which is thereafter allowed to enter between two adjacent teeth of the gear 31 of the second drum 26b. The second drum 26b has an alternate arrangement of the teeth of the gear 31 and the lower bent lugs 28b of the tiltable levers 28, as seen from FIG. 7. Thus, the knitting needles 32 having butts 32a not engaged by the tiltable levers 28 of the second drum 26a are allowed to remain in their position until they are subsequently lowered by a following cam 53.
Means is also provided on the carriage 9 to prevent the tiltable levers 28 on the second drum 26b from being displaced from their set positions due to engagement with needle butts 32a. The means includes an arcuate plate member 51 adjustably mounted on the carriage 9 by means of fastening screws. The plate member 51 has a pair of arms 51a which extend to surround an upper portion of the second drum 26b with a suitable clearance therebetween. Pivotal motion of a tiltable lever 28 from its normal to tilted position is prevented by engagement of its upper projection 28a with the plate member 51. Reverse pivotal motion is also prevented by the plate member 51.
While the present invention has been described in connection with the preferred embodiment, it is apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention as defined in the appended claims and their legal equivalent. | A needle selection mechanism in a hand-operated knitting machine in which collisions of parts are minimized to reduce production of noises is disclosed. The mechanism comprises a patterning data carrier mounted alongside a needle bed and a pair of needle selector units mounted on a carriage and each including first and second drums each having a set of tiltable data storing elements mounted thereon. A set of patterning data are applied from the data carrier to each selector unit to be stored thereon when the unit passes the carrier which is fed from row to row when the carriage passes it. During a movement of the carriage on the needle bed, a preceding one of the selector units effects selective actuations of movable knitting needles in accordance with the data stored thereon. The tilted data storing elements on both drums of a following one of the selector units are restored to their initial positions by a clearing member common to both drums which operates in time before the following unit reaches the data carrier. | 3 |
BACKGROUND OF THE INVENTION
1. Technical Field
Generally, the invention relates to high pressure fluid cutting systems. Particularly, the invention relates to high velocity cutting nozzles for connection to the fluid supply tube of high pressure fluid cutting systems. Specifically, the invention relates to cutting nozzles comprising a housing which threadably connects to the fluid supply tube for receiving pressurized liquid therefrom, with a bushing disposed in the housing that sandwiches a removable sleeved orifice disk therebetween at a spray outlet bore of the housing.
2. Background Information
High pressure liquid cutting devices are commonly used for cutting various sheet materials such as plastics, and masonry materials such as brick and concrete slabs. Such cutting devices are also used for drilling and abrading materials. Such devices are also often used to clean materials such as masonary and steel. Such cutting devices usually include an electric motor which drives a hydraulic pump supplying a working fluid to a high pressure intensifier unit. The intensifier draws a cutting liquid in the form of water from a reservoir, and discharges the water at a very high pressure (e.g. 20,000 to 70,000 psi or more) through the fluid supply tube to the cutting nozzle to produce a fluid jet to cut through the desired material. The fluid jet may range in diameter from about a thousandth of an inch up to about fifteen thousandths of an inch or more, at a velocity of about 1,000 to 3,000 feet per second.
Many prior art cutting nozzles are prone to prematurely wearing out due to abrasion caused by the high pressure and velocity of the water traveling through the nozzles upstream of the orifice. Turbulence upstream of the orifice also causes lack of cohesiveness of the fluid jet. That is, convergence of the various velocity vectors of the fluid within the fluid jet at the orifice only extends for a short distance upon exiting the orifice. This results in a more dispersed fluid jet having less cutting force so only shallower cuts may be made, a wider width of cut or kerf, and more overspraying or wetting of the material adjacent the cut. Conversely, a more cohesive fluid jet provides a finer fluid jet, more precise cutting, and deeper cuts.
One attempt to reduce such turbulence is a liquid jet cutting device and method disclosed in U.S. Pat. No. 3,997,111 issued to Thomas et al. on Dec. 14, 1976. The disclosed device includes a source of high pressure fluid, a jet nozzle, and a high pressure conduit connecting the fluid source to the nozzle. A liquid collimating device is disposed directly upstream of the nozzle comprising a housing interconnected between the conduit and the nozzle. The housing defines a flow collimating chamber directly upstream of the nozzle through which the high pressure liquid is delivered to the nozzle. The cross-sectional area of the flow collimating chamber must be at least greater than one hundred times the cross-sectional area of the nozzle opening. The liquid jet produced is claimed to have relatively little dispersion and a relatively narrow kerf.
An orifice assembly and method providing highly cohesive fluid jet is disclosed in U.S. Pat. No. 5,226,597 issued to Ursic on Jul. 13, 1993. The orifice assembly includes a housing that receives pressurized fluid from a supply tube. The housing has a passageway therein through which the fluid flows. The passageway has an orifice element therein having an orifice for producing the fluid jet, and a converging section disposed upstream of the orifice that extends toward the orifice element. The converging section is designed to reduce turbulence upstream of the orifice and thus produce a more cohesive fluid jet emitted from the orifice. A section having a rounded surface is disposed between the converging section and the orifice element which joins the converging section and an upstream portion of the orifice element. The section is designed to further improve the cohesiveness of the fluid jet by further reducing turbulence upstream of the orifice.
Although these devices are adequate for the purpose for which they were intended, the first device has additional length and adds weight to the cutting assembly. Additionally, neither device directly addresses the problem of nozzle wear.
Another problem with prior art nozzles is the inability to easily change orifice sizes when the particular material requires such. The sapphire orifice disk is typically affixed to the nozzle housing requiring changing out of the entire nozzle, or the use of a press to remove the orifice disk from the housing. Furthermore, the same must be done to replace a worn out orifice disk. If the orifice disk cannot be removed, the entire nozzle must be scrapped.
Therefore, the need exists for an improved high velocity cutting nozzle that reduces turbulence upstream of the orifice to produce a narrow kerf, that has a significantly longer service life prior to wearing out, and having easily replaceable orifice disks.
SUMMARY OF THE INVENTION
Objectives of the invention include providing a high pressure cutting nozzle which has reduced turbulence.
Another objective is to provide a high pressure cutting nozzle with significantly reduced internal wear due to abrasion of the water flow providing a longer service life.
A further objective is to provide a high pressure cutting nozzle in which orifice disks are easily changed to ones having a different orifice size or replaced when worn out.
A still further objective of the invention is to provide such a high pressure cutting nozzle which includes a separate housing and bushing between which the orifice disk is sandwiched, and which solves problems and satisfies needs existing in the art.
These objectives and advantages are obtained by the improved high velocity cutting nozzle for connection to a fluid supply tube of a high pressure fluid cutting system of the present invention, the general nature of which may be stated as including: a housing adapted for connection to the fluid supply tube, a bushing receiving bore extending from the fluid supply tube partially through the housing, and a spray outlet bore extending inwardly from a front surface of the housing which joins with the bushing receiving bore through which the liquid is directed as a high velocity liquid cutting jet; a bushing that closely fits within the bushing receiving bore, having an end surface adapted to closely sealingly engage a mating surface of the housing within the bushing receiving bore, the bushing having a flow-directing bore for receiving the liquid from the fluid supply tube and extending at least partially through the bushing, the flow directing bore including a convergent inlet portion having an annular inner surface for reducing turbulence in the flow-directing bore, and an outlet portion having an annular inner surface and a convergent end surface; and an orifice plate in co-axial fluid communication with the flow-directing bore and the spray outlet bore, the orifice plate fitting within a sleeve receiving bore in one of the bushing and the housing immediately downstream of the flow-directing bore and abutting a shoulder of the bushing, the orifice plate having an orifice of a diameter that is smaller than a minimum diameter of the flow-directing bore for producing a high velocity fluid jet, with the orifice plate being sandwiched between the bushing and the housing.
According to another aspect, the objectives and advantages are obtained by the improved method for extending the service life of a high velocity cutting nozzle, the general nature of which may be stated as including the steps of: producing a flow of high pressure fluid; passing the flow through a flow-directing bore including a convergent inlet portion having an annular inner surface, and through an outlet portion having an annular inner surface and a convergent end surface to remove turbulence; and passing the flow through an orifice closely adjacent the flow-directing bore having an orifice of a diameter that is smaller than a minimum diameter of the flow-directing bore for producing a high velocity fluid jet.
BRIEF DESCRIPTION OF THE DRAWINGS
The preferred embodiments of the invention, illustrative of the best mode in which applicant has contemplated applying the principles, are set forth in the following description and are shown in the drawings and are particularly and distinctly pointed out and set forth in the appended claims.
FIG. 1 is a schematic view of a high pressure water cutting system of the type that may utilize the cutting nozzles of the present invention;
FIG. 2 is a fragmentary longitudinal sectional view of a first embodiment of the cutting nozzle of the present invention having a flow directing bore that includes a straight outlet portion having an annular straight surface and an annular curved convergent surface;
FIG. 3 is a fragmentary longitudinal sectional view of a second embodiment of the cutting nozzle of the present invention having a flow directing bore that includes a straight outlet portion having an annular straight surface and an annular angled convergent surface;
FIG. 4 is a fragmentary longitudinal sectional view of a third embodiment of the cutting nozzle of the present invention having a flow directing bore that includes a flared outlet portion having an annular flared surface and an annular curved convergent surface;
FIG. 5 is a fragmentary longitudinal sectional view of a fourth embodiment of the cutting nozzle of the present invention having a flow directing bore that includes a flared outlet portion having an annular flared surface and an annular curved convergent surface;
FIG. 6 is a partially exploded perspective view of the housing and bushing, with the sleeve, and orifice disk installed within the bushing of the cutting nozzles;
FIG. 7 is an exploded perspective view of the housing, bushing, sleeve, and orifice disk of the cutting nozzle;
FIG. 8 is an exploded perspective view of the housing, bushing, sleeve, orifice disk, and an alternate orifice disk having a larger orifice of the cutting nozzle; and
FIG. 9 is a partially exploded perspective view of the housing, bushing, and orifice disk, with the sleeve, and alternate orifice disk installed within the bushing of the cutting nozzle.
Similar numerals refer to similar parts throughout the drawings.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The high velocity cutting nozzle of the present invention is shown in FIGS. 1 and 2, and is indicated generally at 20 . Cutting nozzle 20 is shown in FIG. 1 positioned as part of a high pressure water cutting system 23 . Cutting system 23 includes a cutting gun 26 having a fluid supply tube 29 to which the cutting nozzle 20 is engaged as explained subsequently. Gun 26 receives high pressure water produced by an electric powered hydraulic pump 32 that supplies a working fluid such as hydraulic fluid through a pipe 35 to a high pressure intensifier unit 38 . The intensifier unit 38 draws a suitable cutting fluid (i.e. water) through a pipe 41 from a reservoir 44 , and discharges the water at a very high pressure through a pipe 47 to an ultra-fine filter 50 to remove any small particulates that might plug up the cutting nozzle 20 . The water passes from filter 50 through a pipe 53 to the fluid supply tube 29 of gun 26 .
Cutting nozzle 20 includes a housing 56 preferably made of high strength steel, a bushing 59 preferably made of steel, an orifice disk 62 preferably made of sapphire, and a sleeve 65 preferably made of plastic or rubber. The housing 56 is generally cylindrical in shape, having an externally threaded portion 68 configured to engage an internally threaded portion 71 of a bore 74 of fluid supply tube 26 of standard guns 26 , and a wrench engaging external hexagonal portion 77 adapted to be engaged by standard hex wrenches (not shown). A bushing receiving bore 80 extends through the threaded portion 68 and partially into the hexagonal portion 77 . A spray outlet bore 83 extends from a convex front surface 86 of housing 56 into the hexagonal portion 77 and joins with the bushing receiving bore 80 . The bushing 59 includes a cylindrical body 89 terminating at a head 92 , the body 89 being of a diameter to closely fit within the bushing receiving bore 80 , with head 92 being of a larger diameter. Head 92 includes a frustoconical or annular tapered surface 95 adapted to engage a mating frustoconical or annular tapered surface 98 of fluid supply tube 29 when cutting nozzle 20 is assembled to gun 26 . A flat end surface 101 of bushing 59 closely engages a mating circular surface 104 of housing 56 within bushing receiving bore 80 when bushing 59 is assembled within housing 56 , with an annular space 107 remaining between head 92 and threaded portion 68 . The bushing 59 further includes a flow directing bore 110 coaxially disposed with a water outlet bore 111 of fluid supply tube 29 of gun 26 , the flow directing bore 110 having a longitudinally tapered inlet portion 113 having an angular funnel-shaped surface 116 and a straight outlet portion 119 having a cylindrical straight surface 122 and a cylindrical curved convergent surface 125 . Surface 116 could also be slightly convex without departing from the spirit of the present invention. A sleeve receiving bore 128 extends inwardly from flat surface 101 of bushing 59 joining with the outlet portion 119 of flow directing bore 110 at a shoulder 131 . The orifice disk 62 includes an orifice 134 of a desired cutting diameter, and pressfits into an inner bore 137 of sleeve 65 . Sleeve 65 closely, but removably fits into the sleeve receiving bore 128 of bushing 59 .
A second embodiment of the cutting nozzle of the present invention is indicated at 140 in FIG. 3 . Cutting nozzle 140 includes the housing 56 , a bushing 59 A, the orifice disk 62 , and the sleeve 65 . The bushing 59 A includes a cylindrical body 89 A terminating at a head 92 A, the body 89 A being of a diameter to closely fit within the bushing receiving bore 80 , with head 92 A being of a larger diameter. Head 92 A includes an annular tapered surface 95 A adapted to engage the annular or cylindrical tapered surface 98 of fluid supply tube 29 when cutting nozzle 140 is assembled to gun 26 . A flat end surface 101 A of bushing 59 A closely engages the circular surface 104 of housing 56 within bushing receiving bore 80 when bushing 59 A is assembled within housing 56 , with the annular space 107 remaining between head 92 A and threaded portion 68 . The bushing 59 A further includes a flow directing bore 10 A coaxially disposed with the water outlet bore 111 of fluid supply tube 29 of gun 26 , the flow directing bore 110 A having the longitudinally tapered inlet portion 113 A having the funnel-shaped surface 116 A and a straight outlet portion 119 A having a cylindrical straight surface 122 A and an annular angled convergent surface 125 A. A sleeve receiving bore 128 A extends inwardly from flat surface 101 A of bushing 59 A joining with the outlet portion 119 A of flow directing bore 110 A at a shoulder 131 A. The orifice disk 62 includes the orifice 134 of a desired cutting diameter, and pressfits into the inner bore 137 of sleeve 65 . Sleeve 65 closely, but removably fits into the sleeve receiving bore 128 A of bushing 59 A.
A third embodiment of the cutting nozzle of the present invention is indicated at 143 in FIG. 4 . Cutting nozzle 140 includes the housing 56 , a bushing 59 B, the orifice disk 62 , and the sleeve 65 . The bushing 59 B includes a cylindrical body 89 B terminating at a head 92 B, the body 89 B being of a diameter to closely fit within the bushing receiving bore 80 , with head 92 B being of a larger diameter. Head 92 B includes tapered surface 95 B adapted to engage the tapered surface 98 of fluid supply tube 29 when cutting nozzle 140 is assembled to gun 26 . A flat end surface 101 B of bushing 59 B closely engages the circular surface 104 of housing 56 within bushing receiving bore 80 when bushing 59 B is assembled within housing 56 , with the annular space 107 remaining between head 92 B and threaded portion 68 . The bushing 59 B further includes a flow directing bore 110 B coaxially disposed with the water outlet bore 111 of fluid supply tube 29 of gun 26 , the flow directing bore 110 B having the longitudinally tapered inlet portion 113 B having a funnel-shaped surface 116 B and a flared divergent outlet portion 119 B having an annular flared surface 122 B and an annular curved convergent surface 125 B. A sleeve receiving bore 128 B extends inwardly from flat surface 101 B of bushing 59 B joining with the outlet portion 119 B of flow directing bore 110 B at a shoulder 131 B. The orifice disk 62 includes the orifice 134 of a desired cutting diameter, and pressfits into the inner bore 137 of sleeve 65 . Sleeve 65 closely, but removably fits into the sleeve receiving bore 128 B of bushing 59 B.
A fourth embodiment of the cutting nozzle of the present invention is indicated at 146 in FIG. 5 . Cutting nozzle 140 includes the housing 56 , a bushing 59 C, the orifice disk 62 , and the sleeve 65 . The bushing 59 C includes a cylindrical body 89 C terminating at a head 92 C, the body 89 C being of a diameter to closely fit within the bushing receiving bore 80 , with head 92 C being of a larger diameter. Head 92 C includes an annular tapered surface 95 C adapted to engage the annular tapered surface 98 of fluid supply tube 29 when cutting nozzle 140 is assembled to gun 26 . A flat end surface 101 C of bushing 59 C closely engages the circular surface 104 of housing 56 within bushing receiving bore 80 when bushing 59 C is assembled within housing 56 , with the annular space 107 remaining between head 92 C and threaded portion 68 . The bushing 59 C further includes a flow directing bore 110 C coaxially disposed with the water outlet bore 111 of fluid supply tube 29 of gun 26 , the flow directing bore 110 C having the longitudinally tapered inlet portion 113 C having a funnel-shaped surface 116 C and a flared divergent outlet portion 119 C having an annular flared surface 122 C and an annular curved convergent surface 125 C. A sleeve receiving bore 128 C extends inwardly from flat surface 101 C of bushing 59 C joining with the outlet portion 119 C of flow directing bore 110 C at a shoulder 131 C. The orifice disk 62 includes the orifice 134 of a desired cutting diameter, and pressfits into the inner bore 137 of sleeve 65 . Sleeve 65 closely, but removably fits into the sleeve receiving bore 128 C of bushing 59 C.
The cutting nozzle 20 (as well as cutting nozzles 140 , 143 , and 146 ) threadably connects to the fluid supply tube 29 of gun 26 by engaging a wrench to the external hexagonal portion 77 of housing 56 . The annular tapered surface 95 of bushing 59 engages the annular tapered surface 98 of fluid supply tube 29 as cutting nozzle 20 is tightened, forcing bushing 59 further into the bushing receiving bore 80 . The flat end surface 101 of bushing 59 closely engages the mating circular surface 104 of housing 56 within bushing receiving bore 80 , sealing nozzle 20 to fluid supply tube 29 . The orifice disk 62 and sleeve 65 are retained within the sleeve receiving bore 128 by the shoulder 131 without being pressfit or otherwise affixed therein. Therefore, upon disassembly of cutting nozzle 20 , the orifice disk 62 with sleeve 65 readily slides out of the sleeve receiving bore 128 without using tools, and may be replaced by an orifice disk 149 within another sleeve 65 having a different size orifice 152 to suite a different cutting job. Likewise, when orifice disk 62 wears out, it may readily be replaced without throwing out the entire cutting nozzle 20 . The cutting nozzle 20 fastens directly to conventional fluid supply tubes 29 and requires no modification thereto.
The method of operation includes the following steps: 1) producing a flow of high pressure fluid; 2) passing the flow through a flow-directing bore including a convergent inlet portion having an annular inner surface, and through an outlet portion having an annular inner surface and a convergent end surface to remove turbulence; and 3) passing the flow through an orifice closely adjacent the flow-directing bore having an orifice of a diameter that is smaller than a minimum diameter of the flow-directing bore for producing a high velocity fluid jet. The outlet portion has one of four configurations: a) the annular inner surface is a cylindrical surface with an annular curved convergent surface downstream thereof; b) the annular inner surface is a cylindrical surface with an annular straight convergent surface downstream thereof; c) the annular inner surface is an annular straight divergent surface with an annular curved convergent surface downstream thereof; and d) the annular inner surface is an annular straight divergent surface and an annular straight convergent surface downstream thereof. In operation, it is believed that the inwardly convex convergent inlet portion of the flow directing bore stabilizes the flow of water to reduces turbulence in the flow-directing bore, producing a more laminar and coherent flow prior to entering the orifice. The various configurations of the outlet portion augment this process by smoothly directing the flow into the orifice, with or without a slight initial expansion of the flow area prior to entering the orifice. The result is less turbulence in the flow producing less wear and a tighter kerf.
It is understood that various materials other than those listed may be used in the construction of the cutting nozzles and various finishes be applied. For example, the bushing might be made of brass or a sand blast finish applied to all the water contacting surfaces rather than a smooth finish to improve cohesiveness of the flow. Also, other housing and bushing configurations may be devised. For example, the sleeve receiving bore may be disposed in the housing rather than in the bushing.
Accordingly, the cutting nozzles provide reduced turbulence to produce a finer kerf, significantly reduced internal wear due to abrasion of the water flow providing a longer service life, orifice disks that are easily changed to ones having a different orifice size or replaced when worn out, and a separate housing and bushing between which the orifice disk is sandwiched which achieves all the enumerated objectives, provides for eliminating difficulties encountered with prior art devices, and solves problems and obtains new results in the art.
In the foregoing description, certain terms have been used for brevity, clearness and understanding; but no unnecessary limitations are to be implied therefrom beyond the requirements of the prior art, because such terms are used for descriptive purposes and are intended to be broadly construed.
Moreover, the description and illustration of the invention is by way of example, and the scope of the invention is not limited to the exact details shown or described.
Having now described the features, discoveries and principles of the invention, the manner in which the improved high velocity cutting nozzle is constructed and used, the characteristics of the construction, and the advantageous, new and useful results obtained; the new and useful structures, devices, elements, arrangements, parts and combinations, are set forth in the appended claims.
TERMS
20 . first embodiment cutting nozzle
23 . high pressure water cutting system
26 . [cutting system] cutting gun
29 . [gun] fluid supply tube
32 . [cutting system] electric powered hydraulic pump
35 . [cutting system] pipe
38 . [cutting system] high pressure intensifier pump
41 . [cutting system] pipe
44 . [cutting system] reservoir
47 . [cutting system] pipe
50 . [cutting system] ultra-fine filter
53 . [cutting system] pipe
56 . [cutting nozzle] housing
59 . [cutting nozzle] bushing
62 . [cutting nozzle] orifice disk
65 . [cutting nozzle] sleeve
68 . [cutting nozzle] externally threaded portion
71 . [fluid supply tube] internally threaded portion
74 . [gun] bore
77 . [housing] externally hexagonal portion
80 . [housing] bushing receiving bore
83 . [housing] spray outlet bore
86 . [housing] convex front surface
89 . [bushing] body
92 . [bushing] head
95 . [head] annular tapered surface
98 . [gun] annular tapered surface
101 . [bushing] flat end surface
104 . [housing] circular surface
107 . [cutting nozzle] annular surface
110 . [bushing] flow directing bore
111 . [gun] water outlet bore
113 . [bore] longitudinally tapered inlet portion
116 . [bore] annular concave surface
“R” radius
119 . [bore] bulbous outlet portion
122 . [outlet portion] annular straight surface
125 . [outlet portion] annular curved convergent surface
128 . [bushing] sleeve receiving bore
131 . [bushing] shoulder
134 . [orifice disk] orifice
137 . [sleeve] inner bore
140 . second embodiment cutting nozzle
143 . third embodiment cutting nozzle
146 . fourth embodiment cutting nozzle
149 . [cutting nozzle] alternate orifice disk
152 . [orifice disk] orifice | A high velocity cutting nozzle for connection to the fluid supply tube of a high pressure fluid cutting system. The nozzle includes a housing which threadably connects to the fluid supply tube for receiving pressurized liquid therefrom. A bushing disposed within the housing sandwiches a removable sleeved jeweled orifice disk therebetween at a spray outlet bore of the housing. The bushing includes a flow directing bore with a convergent inlet portion for reducing turbulence, and an outlet portion having an annular cylindrical or divergent inner surface, and an annular convergent angled or curved end surface. The sleeved orifice disk is in co-axial fluid communication with the flow-directing bore and a spray outlet bore of the housing to facilitate fluid flow. The sleeved orifice disk fits within a sleeve receiving bore in the bushing immediately downstream of the flow-directing bore abutting a shoulder of the bushing. | 1 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This non-provisional application claims priority under 35 U.S.C. §119(a) on Patent Application No(s). 101138330 filed in Taiwan, R.O.C. on Oct. 17, 2012, the entire contents of which are hereby incorporated by reference.
TECHNICAL FIELD
[0002] The disclosure relates to an electrical rotor and stator structure, and more particularly to an electrical rotor and stator structure having outward pillar structures on the surfaces of the magnetic members.
BACKGROUND
[0003] In recent years, with the increasing cost of energy, the regulations on energy consumption have been increasingly stringent in every country. Taking energy conservation in the manufacture industry for example, motors are accounted for more than 70 percentages of the overall electricity consumption. Therefore, how to increase the energy efficiency of the motors has become an important issue. Among different motors, the brushless permanent magnet motor offers a simple design that is easy to maintain and has high efficiency. In particular, an axial flux motor (AFM) of the brushless permanent magnet motor is the one having a smaller length-diameter ratio and suitable for thinner design.
[0004] Magnet is one of key components of the brushless permanent magnet motor that determines the performance and speed thereof. Therefore, methods, that can improve magnets in increasing the energy product, better control of the lines of flux inside the motor and suppressing the flux leakage, can increase the energy efficiency of motors. Hence, the capability of the magnets is a crucial issue in the development of the motors.
[0005] Among various types of magnets, rare-earth (material) magnets generally are strong permanent magnets made from alloys of rare earth elements. Motors using rare-earth magnet have higher energy product and better torque density, thus to be widely used in the mechanical and electrical applications.
[0006] However, the cost of rare earth metals has surged almost threefold in recent years. Hence, price of the motors that use rare-earth magnet has risen. Rising price forces the industry to endeavor to design a motor that utilizes less rare-earth magnets and levels up the energy efficiency of the motors.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] The disclosure will become more fully understood from the detailed description given herein below by way of example with reference to the accompanying drawings, and thus does not limit the disclosure, wherein:
[0008] FIG. 1A is a perspective view of an electrical rotor and stator structure according to one embodiment of the disclosure.
[0009] FIG. 1B is a partially sectional view of a motor with variable axial rotor and stator structure according to one embodiment of the disclosure.
[0010] FIG. 2A is a partially enlarged sectional view of an electrical rotor and stator structure according to one embodiment of the disclosure.
[0011] FIG. 2B is a partially enlarged sectional view of a motor with variable axial rotor and stator structure according to another embodiment of the disclosure.
[0012] FIG. 3A is an enlarged view of an outward pillar structure according to one embodiment of the disclosure.
[0013] FIG. 3B to FIG. 3G are enlarged views of the outward pillar structure according to other embodiments of the disclosure.
[0014] FIG. 4A is a partial schematic layout of the outward pillar structures according to one embodiment of the disclosure.
[0015] FIG. 4B is a partial schematic layout of the outward pillar structures according to another embodiment of the disclosure.
[0016] FIG. 5A is a partially sectional view of an electrical rotor and stator structure according to another embodiment of the disclosure.
[0017] FIG. 5B is a partially sectional view of an electrical rotor and stator structure according to another embodiment of the disclosure.
[0018] FIG. 6A is a partially enlarged sectional view of an electrical rotor and stator structure according to another embodiment of the disclosure.
[0019] FIG. 6B is a partially enlarged sectional view of an electrical rotor and stator structure according to another embodiment of the disclosure.
[0020] FIG. 6C is a partially enlarged sectional view of an electrical rotor and stator structure according to another embodiment of the disclosure.
[0021] FIG. 7 is the result of the magnetic flux between the rotor and the stator, the radius length of the surface area, and with or without the pillar structure.
SUMMARY
[0022] The disclosure provides an electrical rotor and stator structure comprising at least one stator, at least one rotor and a plurality of outward pillar structures. The at least one stator comprises a plurality of first magnetic members. Each first magnetic member has a first surface. The at least one rotor is adapted to be pivotally rotated relative to the at least one stator. The at least one rotor comprises a plurality of second magnetic members wherein each second magnetic member has a second surface facing and opposite to the first surface. The plurality of outward pillar structures is installed on the second surfaces and the first surfaces.
DETAILED DESCRIPTION
[0023] In the following detailed description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the disclosed embodiments. It will be apparent, however, that one or more embodiments may be practiced without these specific details. In other instances, well-known structures and devices are schematically shown in order to simplify the drawing.
[0024] Please refer to FIG. 1A , FIG. 1B and FIG. 2A , FIG. 1A is a perspective view of an electrical rotor and stator structure according to one embodiment of the disclosure. FIG. 1B is a partially sectional view of an electrical rotor and stator structure according to one embodiment of the disclosure. FIG. 2A is a partially enlarged sectional view of an electrical rotor and stator structure according to one embodiment of the disclosure.
[0025] An electrical rotor and stator structure 10 described in the disclosure comprises a stator 11 , a rotor 12 and a plurality of outward pillar structures 13 .
[0026] The stator 11 comprises a plurality of first magnetic members 111 and a shell body 112 . The first magnetic members 111 are mounted on the shell body 112 .
[0027] Specifically, in this embodiment, the shell body 112 comprises a first shell 1121 and a second shell 1122 . A gap is arranged between a first shell 1121 and a second shell 1122 . The first magnetic members 111 are mounted on the first shell 1121 and the second shell 1122 . The first magnetic members 111 are located between the first shell 1121 and the second shell 1122 . Each first magnetic member comprises a pole piece 1111 and a coil 1112 . The coil 1112 is wound around the pole piece 1111 . In other word, the first magnetic member 111 is an electromagnet. Moreover, the pole piece 1111 of each first magnetic member 111 has a first surface 1113 .
[0028] In this embodiment, the material of the pole piece 1111 is soft magnetic composites. The pole piece 1111 may be formed by compressing a mixture of powered magnetic materials containing iron (Fe), silicon (Si), aluminum (Al) and manganese (Mo) into clumps through an insulating binder. The insulating binder may be made of an inorganic material, such as phosphates and oxides.
[0029] The rotor 12 is pivotally disposed on the stator 11 and may rotate relative to stator 11 . The rotor 12 comprises a plurality of second magnetic members 121 , which are permanent magnets. The rotor also comprises a rotating shaft 122 , rotatable relatively to the shell body 112 as well as located between the first shell 1121 and the second shell 1122 . The second magnetic members 121 are attached to the rotating shaft 122 . The second magnetic members 121 are located between the first magnetic members 111 mounted on the first shell 1121 , and the first magnetic members 111 are mounted on the second shell 1122 . Both the second magnetic members 121 have two second surfaces 1211 opposite to each other. In each second magnetic member 121 , one of the second surfaces 1211 faces to the first surface 1113 of the pole piece 1111 mounted on the first shell 1121 , and the other second surfaces 1211 faces to the first surface 1113 of the pole piece 1111 mounted on the second shell 1122
[0030] In this embodiment, the second magnetic members 121 are resin-composition magnets, mainly comprising neodymium (Nd), iron (Fe), and boron (B) elements and produced by compression molding. In this embodiment, the second magnetic members 121 do not comprise dysprosium (Dy) element.
[0031] In this embodiment, the shell body 112 of the stator comprises two shells (the first shell 1121 and the second shell 1122 ), but the disclosure is not limited thereto. In other embodiments, the shell body 112 of the stator 11 may have a single shell, and the first magnetic member 111 exists in one side of the second magnetic member 121 .
[0032] In this embodiment, the outward pillar structures 13 are installed on the first surfaces 1113 and the second surfaces 1211 . The outward pillar structures may be disposed on the first surfaces 1113 or the second surfaces 1211 and be integrally formed into one piece. The outward pillar structures 13 may increase the magnetic flux density existing between the first surface 1113 of the first magnetic member 111 and the second surface 1211 of the second magnetic member 121 . Thereby, the energy efficiency of the motor that utilizes the electrical rotor and stator structure 10 is increased.
[0033] In this embodiment, the outward pillar structures 13 on these first surfaces 1113 and the outward pillar structures 13 on the second surfaces 1211 are arranged opposite to each other (namely, opposite setting), as illustrated in FIG. 2A . Specifically, the opposite setting refers to that when the outward pillar structures 13 on the first surface 1113 is projected on the second surface 1211 , the projected locations thereof are overlapped with the locations of the outward pillar structures 13 on the second surface 1211 completely.
[0034] In this embodiment, the relative setting of the outward pillar structures 13 on the first surface 1113 and the outward pillar structure 13 on the second surface 1211 is not intended to limit the disclosure. For example, in another embodiment as illustrated in FIG. 2B , the outward pillar structures 13 on the first surface 1113 and the outward pillar structure 13 on the second surface 1211 are arranged in a staggered setting (namely, an offset arrangement). The staggered setting refers to that when the outward pillar structures 13 on the first surface 1113 is projected on the second surface 1211 , the projected locations thereof fall in between the locations of the outward pillar structures 13 on the second surface 1211 , instead of overlapping with thereof. The staggered setting between the outward pillar structures 13 on the first surface 1113 and the outward pillar structures 13 on the second surface 1211 offer an advantage to the electrical rotor and stator structure 10 during assembly. Specifically, due to the staggered setting, the interference between the outward pillar structures 13 on the first surface 1113 and the outward pillar structures 13 on the second surface 1211 may be avoided.
[0035] With reference to FIG. 3A , the outward pillar structure 13 may be of cylindrical shape, such as a circular cylinder, but the disclosure is not limited thereto. In other embodiments, the outward pillar structure 13 a may be of a triangular prism (as shown in FIG. 3B ) or the outward pillar structure 13 b may be a square pillar with right angled edges (as illustrated in FIG. 3C ). With reference to FIG. 3D to FIG. 3G , in other embodiments of the disclosure, one end of the outward pillar structure 13 c / 13 d / 13 e / 13 f may be with chamfering and rounded edges 131 c / 131 d / 131 e / 131 f respectively. Furthermore, in this embodiment, the setting of the outward pillar structures 13 is an array (as shown in FIG. 4A ). In other embodiments, the setting of the outward pillar structures 13 is a radial layout (as illustrated in FIG. 4B , namely, arranged radially). However, the setting of the outward pillar structures 13 is not intended to limit the disclosure.
[0036] With reference to FIG. 5A , FIG. 5A is a partially sectional view of an electrical rotor and stator structure according to another embodiment of the disclosure. This embodiment is similar to the embodiment of FIG. 1B , thus only the differences to be addressed.
[0037] The difference between the electrical rotor and stator structure 10 a of this embodiment and that in the embodiment illustrated in FIG. 1B is that the outward pillar structures 13 are only disposed on the first surfaces 1113 , but not the second surfaces 1211 . However, such a setting of the outward pillar structures 13 still can increase the magnetic flux density between the first surfaces 1113 and the second surfaces 1211 of the electrical rotor and stator structure 10 a . Thereby, the energy efficiency of the motor that utilizes the electrical rotor and stator structure 10 a is increased.
[0038] With reference to FIG. 5B , FIG. 5B is a partially sectional view of an electrical rotor and stator structure according to another embodiment of the disclosure, which is similar to that of FIG. 1B , thus only the differences to be addressed.
[0039] The difference between the electrical rotor and stator structure 10 b of this embodiment and that in the embodiment illustrated in FIG. 1B is that the outward pillar structures 13 are only disposed on the second surfaces 1211 , but not the first surfaces 1113 . However, such a setting of the outward pillar structures 13 still can increase the magnetic flux density between the first surfaces 1113 and the second surfaces 1211 of the electrical rotor and stator structure 10 b . Thereby the energy efficiency of the motor that utilizes the electrical rotor and stator structure 10 b is increased.
[0040] With reference to FIG. 6A , FIG. 6A is a partially enlarged sectional view of an electrical rotor and stator structure according to another embodiment of the disclosure. This embodiment is similar to the embodiment of FIG. 2A , thus only the differences to be addressed.
[0041] The difference between the outward pillar structure 13 of this embodiment and that in the embodiment illustrated in FIG. 2A is that the outward pillar structure 13 inclines from the normal vector L 1 of the first surface 1113 and the normal vector L 2 of the second surface 1211 at an angle θ. The angle θ ranges between −45 to 45 degrees. Specifically, the structured centerline L of the outward pillar structure 13 to the normal vector L 1 of the first surface 1113 and to the normal vector L 2 of the second surface 1211 form an acute angle respectively. The inclined setting of the outward pillar structure 13 with respect to the normal vector L 1 of the first surface 1113 or to the normal vector L 2 of the second surface 1211 may increase the magnetic flux density. In this embodiment, the outward pillar structures 13 are mounted on the first surface 1113 and the second surface 1211 and incline thereof at an angle, but the disclosure is not limited thereto. For example, in another embodiment, only the outward pillar structures 13 on the second surfaces 1211 incline thereof at an angle, as illustrated in FIG. 6B . Moreover, in still another embodiment, only the outward pillar structures 13 on the first surfaces 1113 incline thereof at an angle, as illustrated in FIG. 6C .
[0042] According to various designs of the electrical rotor and stator structure of the embodiments described above, the Maxwell® simulation program is used to calculate the magnetic flux, maximum torque and magnetic flux at the Z axis of the electrical rotor and stator structure of each embodiment of the disclosure and those from prior art for comparison. The data is plotted in FIG. 7 and listed in Table 1 and Table 2.
[0043] With reference to FIG. 7 , the horizontal axis represents the length of the section of the first surface 1113 or the second surface 1211 (millimeter, mm), whereas the vertical axis represents the scale of the magnetic flux (milli-tesla, mTesla). The dashed line is the distribution of the magnetic flux of the electrical rotor and stator structures from prior art having the first surface 1113 and the second surface 1211 without the outward pillar structures 13 . The solid line is the distribution of the magnetic flux of the electrical rotor and stator structures of the embodiments of the disclosure having the first surface 1113 and or second surface 1211 having the outward pillar structures 13 . The outward pillar structures 13 are arranged in setting of a radial layout. Each outward pillar structure 13 is a circular cylinder with an outer diameter of 1.0 mm and 0.5 mm in height. Furthermore, the outward pillar structure 13 incline toward the first surface 1113 or the second surface 1211 at an angle of 30 degrees from the normal vector thereof. According to FIG. 7 , the average magnetic flux exists in the electrical rotor and stator structure of the embodiment, whose first surfaces 1113 or second surfaces 1211 has the outward pillar structures 13 , (solid line) is greater than that of the electrical rotor and stator structure without the outward pillar structures of prior art (dashed line). Therefore, the results produced by the simulation program prove that installation of the outward pillar structures 13 on the first surfaces 1113 of the first magnetic members 111 or on the second surfaces 1211 of the second magnetic members 121 may improve and increase the magnetic flux in the air gap located between the rotor and stator of the electrical rotor and stator structure. Thereby, the energy efficiency of the motor is increased.
[0044] A list of data of maximum torque, magnetic flux and magnetic flux in Z axis of different setting of the electrical rotor and stator structure is shown in Table 1. Data of the electrical rotor and stator structure without the outward pillar structures 13 of the prior art is regarded as a control group, The electrical rotor and stator structures of the embodiments 1 to 19 of the disclosure have the outward pillar structures 13 mounted on the second surfaces 1211 at various angles for different embodiments. In addition, the positive value of the angle means that the outward pillar structures 13 incline to the right of the normal vector L 2 of the second surface 1211 and the negative value of the angle represents that the outward pillar structures 13 incline to the left of the normal vector L 2 of the second surface 1211 . Except the differences of the outward pillar structure and equivalent air gap, the rest of conditions are identical among the control group, and the embodiments 1 to 19 of the disclosure. The above-mentioned magnetic flux is defined as that from the first surface 1113 to the second surface 1211 , whereas the magnetic flux in the Z axis represents the portion of magnetic flux from the first surface 1113 to the second surface 1211 in Z axis direction. The definition of the acronym mN-m is milli-newton meters, the unit of torque.
[0000]
TABLE 1
Maximum
Magnetic
Magnetic flux
torque
flux
in Z axis
Group
Structural feature
(mN-m)
(mTesla)
(mTesla)
Control
No outward pillar structure
316
460
418
Group
Embodiment 1
Outward pillar structure at
331
500
463
−45 degrees
Embodiment 2
Outward pillar structure at
335
502
465
−40 degrees
Embodiment 3
Outward pillar structure at
335
502
466
−35 degrees
Embodiment 4
Outward pillar structure at
332
499
463
−30 degrees
Embodiment 5
Outward pillar structure at
326
492
456
−25 degrees
Embodiment 6
Outward pillar structure at
335
497
461
−20 degrees
Embodiment 7
Outward pillar structure at
339
499
463
−15 degrees
Embodiment 8
Outward pillar structure at
336
495
459
−10 degrees
Embodiment 9
Outward pillar structure at −5
337
495
459
degrees
Embodiment
Outward pillar structure at 0
340
496
460
10
degree
Embodiment
Outward pillar structure at 5
332
498
462
11
degrees
Embodiment
Outward pillar structure at 10
337
496
460
12
degrees
Embodiment
Outward pillar structure at 15
333
497
461
13
degrees
Embodiment
Outward pillar structure at 20
336
498
462
14
degrees
Embodiment
Outward pillar structure at 25
337
494
457
15
degrees
Embodiment
Outward pillar structure at 30
338
496
460
16
degrees
Embodiment
Outward pillar structure at 35
334
502
465
17
degrees
Embodiment
Outward pillar structure at 40
336
500
463
18
degrees
Embodiment
Outward pillar structure at 45
338
501
463
19
degrees
[0045] Based on the data in Table 1, the maximum torque, the magnetic flux and the magnetic flux in Z axis of the outward pillar structures 13 of each embodiment are greater than those of the electrical rotor and stator structure of the control group that has no outward pillar structure. Among all, the embodiment has the outward pillar structure 13 at 0 degree(s) producing the upmost maximum torque; at −40, −35, and 35 degrees the highest magnetic flux; and at −35 degrees the highest magnetic flux in Z axis.
[0046] Table 2 contains a list of data of maximum torque, magnetic flux and magnetic flux in Z axis of different settings of the electrical rotor and stator structure. Data of the electrical rotor and stator structure without the outward pillar structures 13 of the prior art is regarded as a control group. The electrical rotor and stator structures of the embodiments 1 to 19 of the disclosure have the outward pillar structures 13 mounted on both the first surface 1113 and the second surfaces 1211 at various angles for different embodiments. The positive value of the angle means that the outward pillar structures 13 incline to the right of the normal vector L 1 of the first surface 1113 and the outward pillar structures 13 incline to the right of the normal vector L 2 of the second surface 1211 . The negative value of the angle represents that the outward pillar structures 13 incline to the left of the normal vector L 1 of the first surface 1113 and to the left of the normal vector L 2 of the second surface 1211 . Except the differences of the outward pillar structure and equivalent air gap, the rest of conditions are identical among the control group, and the embodiments 1 to 19 of the disclosure. The magnetic flux is defined as that from the first surface 1113 to the second surface 1211 , whereas the magnetic flux in the Z axis represents the portion of magnetic flux from the first surface 1113 to the second surface 1211 in Z axis direction.
[0000]
TABLE 2
Maximum
Magnetic flux
torque
Magnetic flux
in Z axis
Group
Structural feature
(mN-m)
(mTesla)
(mTesla)
Control
No outward pillar structure
347
499
456
Group
Embodiment 1
Outward pillar structure at
376
595
553
−45 degrees
Embodiment 2
Outward pillar structure at
372
592
550
−40 degrees
Embodiment 3
Outward pillar structure at
376
586
544
−35 degrees
Embodiment 4
Outward pillar structure at
367
581
539
−30 degrees
Embodiment 5
Outward pillar structure at
381
588
547
−25 degree
Embodiment 6
Outward pillar structure at
384
587
546
−20 degrees
Embodiment 7
Outward pillar structure at
374
585
544
−15 degrees
Embodiment 8
Outward pillar structure at
374
576
535
−10 degrees
Embodiment 9
Outward pillar structure at
378
579
538
−5 degrees
Embodiment
Outward pillar structure at 0
369
580
539
10
degree
Embodiment
Outward pillar structure at 5
372
581
540
11
degrees
Embodiment
Outward pillar structure at
373
583
542
12
10 degrees
Embodiment
Outward pillar structure at
359
578
537
13
15 degrees
Embodiment
Outward pillar structure at
362
586
545
14
20 degrees
Embodiment
Outward pillar structure at
365
588
547
15
25 degrees
Embodiment
Outward pillar structure at
376
589
548
16
30 degree
Embodiment
Outward pillar structure at
371
587
545
17
35 degrees
Embodiment
Outward pillar structure at
373
590
548
18
40 degrees
Embodiment
Outward pillar structure at
376
589
546
19
45 degrees
[0047] Based on the data in Table 2, the maximum torque, the magnetic flux and the magnetic flux in Z axis of each embodiment having the outward pillar structures 13 are greater than those of the electrical rotor and stator structure of the control group having no outward pillar structure. Among all, the embodiment has the outward pillar structure 13 at −20 degrees producing the upmost maximum torque; and at −45 degrees the highest magnetic flux and the highest magnetic flux in Z axis.
[0048] It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed embodiments. It is intended that the specification and examples be considered as exemplary only, with a true scope of the disclosure being indicated by the following claims and their equivalents. | An electrical rotor and stator structure includes at least one stator, at least one rotor and multiple outward pillar structures. The at least one stator includes multiple first magnetic members. Each first magnetic member has a first surface. The at least one rotor is able to be rotated pivotally relative to the at least one stator. The at least one rotor includes multiple second magnetic members. Each second magnetic member has a second surface facing and opposite to the first surface. The multiple outward pillar structures are installed on the second surfaces and the first surfaces. | 7 |
CROSS-REFERENCE TO RELATED APPLICATIONS
This U.S. non-provisional patent application claims priority under 35 U.S.C. §119 of Korean Patent Application 2005-05007 filed on Jan. 19, 2005, the entire contents of which are hereby incorporated by reference.
BACKGROUND
1. Field of the Invention
The present invention relates to image sensors, and more particularly relates to CMOS image sensors and methods of operating and fabricating the same.
2. Description of the Related Art
The rapid advancement of digital camera technology and a resulting increase of their popularity has made high performance digital cameras in high demand among consumer electronics. The basic components of a digital camera that determine its performance level are an optical lens and an image sensor. The image sensor functions to transform light applied thereto (through the optical lens) into an electronic signal representing an image.
A typical image sensor is composed of a pixel array in which a plurality of pixels are arranged in a two dimensional matrix. Each pixel includes a light detection unit (or a photodetector), and a transmission and signal output (readout) unit. Image sensors may be normally classified into two types: the charge coupled device image sensors (hereinafter, referred to as CCD image sensors); and the complementary metal-oxide-semiconductor image sensors (hereinafter, referred to as CMOS image sensors). The CCD image sensor employs MOS (metal oxide semiconductor, field effect transistor) capacitors for transferring and outputting signals and charge carriers are stored in a capacitor are transferred to an adjacent capacitor, by a potential difference between the capacitors. By comparison, the CMOS image sensor utilizes a switching scheme sequentially detecting output signals of MOS transistors that are formed in the pixels thereof.
Thus, the CCD image sensors are able to take better images than CMOS image sensors because of having less noise therein, but have disadvantages of higher product costs and larger power consumption. In other words, the CMOS image sensors have the advantages of lower power operation, (low power consumption), compatibility with integrated or operatively coupled CMOS circuits, random accessing of image data, reduced cost (e.g., by using standard CMOS techniques), and so forth. Thus, the CMOS image sensors are more widely used for various applications such as digital cameras, smart phones, PDAs, notebook computers, security cameras, barcode sensors, high definition televisions, high resolution cameras, toys, and so on.
FIG. 1A is an equivalent circuit diagram illustrating the pixel structure of a conventional CMOS image sensor including a photo-receiving device and four transistors (hereinafter, referred to as ‘four-transistor pixel structure’), and FIG. 1B is a timing diagram illustrating an operation of the CMOS image sensor of FIG. 1A .
Referring to FIG. 1A , the image sensor with four-transistor pixel structure is composed of four transistors, (i.e., a transfer transistor 13 , a reset transistor 15 , a drive transistor 17 , a selection transistor 19 ), and a photo-receiving device 11 .
The typical operation of the four-transistor pixel structure is as follows. Referring to FIG. 1B , a selection voltage φSG is applied to the (selection) gate of the selection transistor 19 during a signal output period Td, turning the selection transistor 19 ON. After the selection transistor 19 is turned ON, a reset voltage φRG is applied to the (reset) gate RG of the reset transistor 15 , by which the reset transistor 15 is turned ON to reset a floating diffusion node 14 to a power supply voltage level VDD approximately. Thereby, the pixel is reset. Then, the supply voltage level VDD is applied to the (drive) gate DG of the drive transistor 17 as a drive voltage φDG, so that a reference voltage Vref is provided to an output node Vout within a first signal output period Td 1 .
After resetting the pixel, when light is incident upon the photo-receiving device 11 , electron-hole pairs (EHP) are generated proportionally in response to the incident light. And then, if a transfer voltage φTG is applied to the transfer gate TG, the potential barrier (resistance) between the photo-receiving device 11 and the floating diffusion node 14 becomes lower (allowing a transfer of signal charges from the photo-receiving device 11 to the floating diffusion node 14 ). Thereby, the potential at the floating diffusion node 14 varies in proportion with the amount of signal charges transferred thereto. Thus, the drive voltage φDG applied to the drive gate DG drops down under the initial (supply) voltage VDD, and a (pixel) signal data voltage Vpix appears at an output node Vout within a second signal output period Td 2 . An image signal is output as a value arising from a difference value Vsig between the reference voltage Vref and the signal data voltage Vpix.
As such, it is very important to entirely transfer the signal charges, which are generated at the photo-receiving device 11 , to the floating diffusion node 14 through the transfer gate TG. If the signal charges generated remain in the photo-receiving device 11 without being wholly transferred to the floating diffusion node 14 , the remaining signal charges causes the phenomenon of “image lagging” that leaves afterimages in the next frame, resulting in degradation of picture quality in the image sensor.
SUMMARY OF THE INVENTION
Various aspects of the present invention provide an image sensor, for example, a CMOS image sensor, and other aspects of the invention may be applicable to provide another type of image sensor, e.g., a CCD image sensor. Exemplary embodiments of the invention provide a CMOS image sensor having the four-transistor pixel structure, wherein at least one of the (four) transistors (e.g., the Transfer transistor, and/or a Drive Transistor) has a stacked gate structure that provides a capacitive self-boosting effect. The boosting effect may be applied to elevate a bias voltage applied to the transfer gate or to reduce an electrostatic potential.
An aspect of the present invention prevents the “image lagging” effect in the image sensor, e.g., by elevating a bias voltage applied to the transfer gate or reducing an electrostatic potential at the photo-receiving device. As the bias voltage to the transfer gate becomes higher, the potential barrier between the photo-receiving device and the floating diffusion node becomes lower. Also, the lower potential at the photo-receiving device lowers the potential barrier between the photo-receiving device and the floating diffusion node.
However, the scheme that increases the bias voltage to the transfer gate needs to forcibly increase the bias voltage of the transfer gate by means of a high voltage generator that supplies a high voltage to the transfer gate. Meanwhile, the scheme of lowering the potential at the photo-receiving device causes a decrease of charge accumulation capacity in the photo-receiving device and an overflow of signal charges.
Accordingly, embodiments of the present invention provide a high quality image sensor and methods of operating and fabrication the same.
An aspect of the invention provides a CMOS image sensor comprised of a photo-receiving device (e.g., a photodiode), and a signal transformer converting signal charges of the photo-receiving device into voltages. The signal transformer includes a transfer gate, a reset gate, a drive gate, and a selection gate. Thus, each pixel of the image sensor is composed of the photo-receiving device, the transfer gate, the reset gate, the drive gate, and the selection gate. The control gate controls the operation of transferring the signal charges from the photo-receiving device to a floating diffusion region that is a charge storage area. For this, a transfer voltage is applied to the transfer gate as a control signal. The reset gate controls an operation of initializing (resetting) the signal charges of the floating diffusion region, for which a reset voltage is applied to the reset gate as a control signal. The drive gate is connected to the floating diffusion region, sensing a potential corresponding to the signal charges transferred to the floating diffusion region. The selection gate controls the operation of outputting the sensed potential, for which a selection voltage is applied to the selection gate as a control signal.
In the exemplary embodiments of the invention shown in the figures, a boosting gate is disposed over one of the transfer and drive gates with an interposing (high-dielectric) insulation film. Thereby, the transfer gate, the dielectric film, and the boosting gate function as a capacitor. Similarly, the drive gate, the dielectric film, and the boosting gate finction as a capacitor. Thus, a bias voltage (boosting voltage) applied to the boosting gate is coupled with the transfer gate and/or the drive gate. As a result, the transfer gate is supplied with the sum of the voltage of the transfer voltage directly applied thereto and the voltage (boosting gate-coupling voltage) coupled thereto by the boosting voltage applied to the boosting gate pattern. Similarly, with a driving gate-coupling voltage (i.e., the boosting gate-coupling voltage) coupled to the drive gate by the boosting voltage, the floating diffusion region is variable in potential and thereby a dynamic range of the image sensor is enlarged.
When after applying the transfer voltage to the transfer gate and floating the transfer gate, the boosting voltage is applied to the boosting gate pattern, the transfer gate is supplied with the sum of the transfer voltage and the boosting gate-coupling voltage as a result. As the boosting gate-coupling voltage (i.e., a transfer coupling voltage) as well as the transfer voltage is applied to the transfer gate, the transfer voltage and the boosting voltage applied to the boosting gate do not need to be (externally supplied) high voltages. Therefore, it is unnecessary to provide a high-voltage generator.
Preferably, the boosting gate is electrically connected to the selection gate. In other words, the selection voltage applied to the selection gate is simultaneously applied also to the boosting gate as the boosting voltage. Thus, there is no need of an additional voltage supply source for supplying the boosting voltage. And, it is easy to supply the boosting voltage to the boosting gate just by using the selection voltage applied directly to the boosting gate pattern.
The photo-receiving device may be a photodiode, a phototransistor, a pinned photodiode, a photogate, a MOSFET, or so forth, without limited to a specific one.
Embodiments of the invention also provide a method of fabricating each pixel of an image sensor. The method comprises: confining an active region in a semiconductor substrate by a field isolation process; sequentially forming a first conductive film, a dielectric film, and a second conductive film on the semiconductor substrate; forming a boosting gate (pattern) from the second conductive film (e.g., by conducting a first photolithography and etching process); forming a transfer gate, a reset gate, a drive gate, and a selection gate from the first conductive film (e.g., by conducting a second photolithography and etching process against the first dielectric film); forming a photo-receiving device; and forming a local interconnection line to electrically connect the boosting gate(s), which is disposed over the transfer gate and/or the drive gate, to the selection gate(s) of pixels.
The method may further comprise forming an analog capacitor in a peripheral circuit area. In this case, while forming the boosting gate from patterning the second conductive film by means of the first photolithography and etching process, the second conductive film of the peripheral circuit area is patterned to form the top electrode of the analog capacitor at the same time. And, while forming the transfer gate, the reset gate, the drive gate, and the selection gate from patterning the dielectric film and the first conductive film by means of the second photolithography and etching process, the dielectric film and the first conductive film those positioned in the peripheral circuit area are patterned to form a dielectric film and the bottom electrode of the analog capacitor at the same time.
In this method, since the boosting gate (pattern) is disposed over the transfer gate (adjacent to the photo-receiving device), it does not cause an injection of ionic impurities into the substrate under the transfer gate even though there may be a misalignment during an ion implantation process for forming the photo-receiving device.
BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments of the present invention will be described below in more detail with reference to the accompanying drawings. The present invention may, however, be embodied in different forms and should not be constructed 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 accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the present invention and, together with the description, serve to explain principles of the present invention. In the drawings, the thickness of layers and regions are exaggerated for clarity. It will also be understood that when a layer is referred to as being on another layer or substrate, it can be directly on the other layer or substrate, or intervening layers may also be present. In the drawings, like numerals and labels refer to like elements throughout the specification, and:
FIG. 1A is a schematic circuit diagram illustrating a pixel structure of a conventional CMOS image sensor including a photo-receiving device and four transistors;
FIG. 1B is a waveform diagram showing an operation by the CMOS image sensor of FIG. 1A ;
FIG. 2A is a top view of an image sensor having a four transistor pixel structure in accordance with a preferred embodiment of the invention;
FIG. 2B is a sectional view along the section line I-I of FIG. 2A , and FIG. 2C is a sectional view along the section line II-II of FIG. 2A ;
FIG. 3 is a detail from FIG. 2B or 2 C illustrating a boosting gate-coupling voltage φBG combined to a transfer gate 105 a by a boosting voltage φBG applied to a boosting gate 109 a shown in FIGS. 2A through 2C ;
FIGS. 4A through 4D are electrostatic potential views illustrating the transfer of signal charges from a photo-receiving device to a floating diffusion region in an image sensor in accordance with an embodiment of the invention;
FIG. 5A is a top view illustrating an image sensor having a four transistor structure in accordance with another preferred embodiment of the invention, FIG. 5B is a sectional view along the section line I-I of FIG. 5A , and FIG. 5C is a sectional view along the section line II-II of FIG. 5A ;
FIG. 6A is a schematic diagram of the image sensor shown in FIGS. 2A through 2C ;
FIG. 6B is a waveform diagram of signals in the image sensor of FIG. 6A illustrating the operation of the image sensor shown in FIG. 6A ;
FIG. 7A is a schematic diagram of the image sensor shown in FIGS. 5A through 5C , and FIG. 7B is a waveform diagram of signals illustrating an operation of the image sensor shown in FIG. 7A ; and
FIGS. 8A through 13A and 8 B through 13 B are sectional diagrams illustrating processing steps for fabricating the image sensor show in FIGS. 2A through 2C , FIGS. 8A through 13A being taken along the section line I-I of FIG. 2A while FIGS. 8B through 13B being taken along the section line II-II of FIG. 2A .
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
FIG. 2A is a top view of an integrated image sensor having a four-transistor pixel structure in accordance with an embodiment of the invention. FIG. 2B is a sectional view along the section line I-I of FIG. 2A , and FIG. 2C is a sectional view along the section line II-II of FIG. 2A .
Referring FIGS. 2A through 2C , the CMOS image sensor includes a plurality of pixels, and each pixel is composed of a photo-receiving device PD ( 115 ) for receiving right, a transfer gate (TG) 105 a for transferring signal charges from the photo-receiving device PD ( 115 ) to a floating diffusion region (FD) 117 , a reset gate (RG) 105 b for discharging the signal charges form the floating diffusion region 117 to a reset diffusion region (RD) 119 , a drive gate (DG) 105 c for outputting a voltage (by amplifying the voltage of the signal charges stored in the floating diffusion region 117 ), and a selection gate (SG) 105 d. A boosting gate 109 a (BG) is disposed (patterned) over the transfer gate (TG) 105 a, with an interposing dielectric film 107 a therebetween. A plurality of pixels each having this structure are arranged in a two-dimensional matrix, forming a pixel array of the image sensor.
The boosting gate 109 a is electrically connected to the selection gate 105 d by a first local metal line 131 a (and through contact plugs 129 a and 129 d in the contact holes 127 a and 127 d, see FIG. 2B ). The floating diffusion region 117 is electrically connected to the drive gate 105 c by a second local metal line 131 b (and through contact plugs 129 b and 129 c in the contact holes 127 b and 127 c, see FIG. 2C ). The interconnections shown in FIG. 2A , between the boosting gate 109 a and the selection gate 105 d, and between the floating diffusion region 117 and the drive gate 105 c, are just examples and may be modifiable in various other arrangements and patterns.
The photo-receiving device PD 115 is formed in an active region 102 A and the gates 105 a - 105 d are formed over another active region 102 B. The active regions 102 A and 102 B are connected to each other, and are electrically isolated from their adjacent active regions by field isolation films 103 ( FIGS. 2B & 2C ).
The photo-receiving device PD 115 may be a photodiode composed of an N-region 111 and a P-region 113 (e.g., adjacent to each other). The transfer gate 105 a (TG) is located adjacent to the photo-receiving device 115 . The photo-receiving device 115 is not confined in form to a photodiode, and may instead be implemented as a phototransistor, a pinned photodiode, a photogate, a MOSFET, or so forth.
Referring to FIGS. 2A and 2C , the floating diffusion region 117 (FD) is disposed between the transfer gate 105 a and the reset gate 105 b. And the reset diffusion region 119 is disposed between the reset gate 105 b and the drive gate 105 c. A voltage VDD is applied to reset the reset diffusion region 119 . The drive gate 105 c is disposed between the reset diffusion region 119 (held at voltage VDD) and a first impurity diffusion region 121 . The first impurity diffusion region 121 is disposed between the drive gate 105 c and the selection gate 105 d, and a second impurity diffusion region 123 is disposed between the selection gate 105 d and the field isolation film 103 .
On the other hand, it is practicable to exchange the positions of the selection gate 105 d and the drive gate 105 c relative to each other. For example, the reset diffusion region 119 may be designed to be disposed between the reset gate 105 b and the selection gate 105 c.
Differing from a conventional pixel structure (see FIG. 1A ), the “four transistor” pixel structure according to an embodiment of the invention comprises the boosting gate 109 a that is positioned over the transfer gate 105 a with an interposing the dielectric film 107 a therebetween. Further, the boosting gate 109 a may be electrically connected to the selection gate 105 d. Thus, when the transfer gate 105 a is floating and a predetermined bias voltage (i.e., selection voltage) φSG is applied, after applying a predetermined bias voltage (i.e., transfer voltage) φTG, to the transfer gate 105 a, the boosting gate 109 a is charged with a boosting (e.g., boosted) voltage φBG by the selection voltage φSG. Thereby, the boosting voltage φBG makes the floating transfer gate 105 a be further coupled with a boosting gate-coupling voltage φCBG. As a result, the transfer gate 105 a is charged with the transfer voltage φTG and the boosting gate-coupling voltage φCBG. By this (boosting) mechanism, it is practicable to sufficiently lower the potential barrier between the photo-receiving device 115 and the floating diffusion region 117 without applying an additional (e.g., external) high voltage to the transfer gate 105 a, while enhancing the efficiency of transferring signal charges in the CMOS image sensor.
FIG. 3 is a detail from FIG. 2B or 2 C further illustrating the boosting gate-coupling voltage φCBG combined to the transfer gate 105 a (TG) by the boosting voltage φBG applied to the boosting gate 109 a as shown in FIGS. 2A through 2C . It is now assumed that C1 denotes the capacitance between the transfer gate 105 a and a transfer channel 116 formable between the floating diffusion region 116 and the photo-receiving device 115 . And C2 denotes the capacitance between the transfer gate 105 a and the boosting gate 109 a. Then, a final transfer gate voltage φFTG applied to the transfer gate 105 a is defined by the following Equation 1:
φ FTG={C 1/( C 1+ C 2)}*φBG+φTG [Equation 1]
From Equation 1, it can be seen that the voltage value {C 1 /(C 1 +C 2 )}*φBG, (i.e., corresponding to the boosting gate-coupling voltage φCBG), is applied to the transfer gate 105 a in addition to the transfer voltage φTG. Further, it is simple and easy to apply the boosting voltage φBG because the voltage applied to the selection gate 105 d is also used for the boosting voltage φBG applied to the boosting gate 109 a. For raising a coupling ratio {C 1 /(C 1 +C 2 )} therein, it is preferable for the dielectric film 107 a to be formed of a material with high dielectric constant.
Now, a mechanism of transferring signal charges from the photo-receiving device (PD) 115 to the floating diffusion region (FD) 117 will be described with reference to FIGS. 4A through 4D .
FIGS. 4A through 4D are electrostatic potential diagrams illustrating the transfer of signal charges.
FIG. 4A shows the potential in the photo-receiving device PD and in the floating diffusion region FD after completing the reset operation for the pixel. As illustrated in FIG. 4A , between the photo-receiving device PD and the floating diffusion region FG, the transfer gate 105 a is located under the boosting gate 109 a with interposing the dielectric film 107 a therebetween. The reset gate RG is located between the floating diffusion region FD and the reset diffusion region held at voltage VDD (not shown). And, the field isolation film (FOX) 103 is positioned at the other side of the photo-receiving device PD opposite from the transfer gate TG.
The electrostatic potentials of the photo-receiving device PD and the floating diffusion region FD are determined by the concentration of (doping) impurities. For instance, the electrostatic potential under the transfer gate 105 a is 0V and the electrostatic potential under the reset gate RG is 0V. The electrostatic potential under the field isolation film (FOX) 103 is 0V. The electrostatic potentials under the transfer gate 105 a, the reset gate RG, and the field isolation film 103 may be established in various values without instead of the above values.
If the reset voltage φRG is applied to the reset gate RG and thereby the reset operation is conducted for the pixel, signal charges remaining in the floating diffusion region FD are all removed. Therefore, when light hν is incident upon the photo-receiving device PD after resetting the pixel, pixel signal charges 41 are trapped in a potential well 411 generated by potential differences under the photo-receiving device, the field isolation film, and the transfer gate.
Referring to FIG. 4B , next when the transfer voltage φTG is applied to the transfer gate TG, the electrostatic potential under the transfer gate TG decreases and the potential barrier between the photo-receiving device PD and the floating diffusion region FD is lowered. As a result, the signal charges 43 are transferred to the floating diffusion region FD. Otherwise, unless the transfer voltage φTG applied to the transfer gate TG makes the electrostatic potential thereunder to be sufficiently lowered (i.e., unless the electrostatic potential under the transfer gate TG is lowered to the bottom of the potential well 411 ), some signal charges 45 may remain at the bottom of the potential well 411 .
Therefore, according to the invention, for the purpose of completely transferring the (remaining) signal charges 45 , which may remain at the bottom of the potential well 411 , to the floating diffusion region FD, the boosting voltage φBG is applied to the boosting gate BG over the transfer gate TG (e.g., after removing the transfer voltage φTG applied to the transfer gate TG (i.e., after floating the transfer gate TG)). Thus, the boosting gate-coupling voltage φCBG is further coupled to the transfer gate TG and as illustrated in FIG. 4C , the electrostatic potential under the transfer gate TG is lowered to the bottom of the potential well 411 (or less) and thereby the signal charges 45 remaining at the bottom of the potential well 411 are entirely transferred to the floating diffusion region FD.
Referring to FIG. 4D , when the boosting voltage φBG is removed from the boosting gate 109 a, the remaining signal charges 45 transferred to the floating diffusion region FD are stored in a potential well 413 generated by electrostatic potential differences among the floating diffusion region FD, the substrate under the transfer gate TG, and the substrate under the reset gate RG. Accordingly, the 10 potential of the floating diffusion region FD is changed based on the transferred signal charges 45 .
A voltage corresponding to the potential of the floating diffusion region FD, as changed by the signal charges 45 transferred to the floating diffusion region FD, is applied to the drive gate DG as the drive voltage φDG.
FIG. 5A is a top view illustrating a pixel in an image sensor, pixel having a four-transistor pixel structure in accordance with another embodiment of the invention. FIG. 5B is a sectional view along the section line I-I of FIG. 5A , and FIG. 5C is a sectional view along the section line II-II of FIG. 5A .
Referring to FIGS. 5A through 5C , the architecture of the pixels of the image sensor according to this embodiment is substantially similar to that of the first embodiment ( FIG. 2A ), except that a drive gate 505 c is located under a boosting gate 509 c with interposing a dielectric film 507 a therebetween. The boosting gate 509 c is again connected to a selection gate 505 d.
The local interconnections between the boosting gate 509 a and the selection gate 505 d, and between a floating diffusion region 517 and the drive gate 505 c, are illustrated just as examples and may be modified in various patterns.
According to this embodiment of the invention, the boosting gate-coupling voltage φCBG is generated at the drive gate 505 c (e.g., not the transfer gate TG 505 a ) by the boosting voltage φBG applied to the boosting gate 509 c, resulting in a variation of the electrostatic potential in the floating diffusion region 517 . For instance, the depth of the potential well 413 (see FIGS. 4A to 4D ) may be increased more than it was in the case of FIGS. 4A through 4D . Therefore, the dynamic range of the image sensor may be enlarged.
Operation of the Image Sensor
FIG. 6A is a schematic diagram of the image sensor shown in FIGS. 2A through 2C , and FIG. 6B is a waveform diagram of signals in the image sensor of FIG. 6A illustrating the operation of the image sensor shown in FIG. 6A .
First, referring to FIG. 6A , each of the pixels of the image sensor according to the first embodiment of the invention is comprised of a photo-receiving device 61 , a transfer transistor 63 having stacked gate structure, a reset transistor 65 , a drive transistor 67 , and a selection transistor 69 . The transfer transistor 63 includes a stacked gate structure formed of the transfer gate TG, the high-dielectric film, and the boosting gate BG. The boosting gate BG may be electrically connected to the selection gate SG of the selection transistor 69 . The transfer transistor 63 transfers the signal charges that are generated at the photo-receiving device 61 , to the floating diffusion region 64 .
Referring to FIG. 6B , a first selection voltage φSG 1 is applied to the selection gate SG of the selection transistor 69 during the first signal output phase Td 1 (t 0 ˜t 3 ) of the signal output period, which turns the selection transistor 69 ON. After turning the selection transistor 69 ON (at t 0 ), the reset voltage φRG is applied to the reset gate RG of the reset transistor 65 within the period t 1 ˜t 2 thus turning ON the reset transistor 65 is turned (to make the potential of the floating diffusion region 64 be set to a reference potential VFD, resetting the pixel). Thus, when the voltage corresponding to the reference potential VFD of the floating diffusion region 64 is applied to the drive gate DG of the drive transistor 67 (as the drive voltage φDG) at the time t 2 , the reference voltage Vref is output to the output node Vout at about time t 2 .
If light is incident on the photo-receiving device 61 (e.g., from a lens), electron-hole pairs are generated and accumulated therein. After resetting the pixel, if the transfer voltage φTG is applied to the transfer gate TG at the time t 3 , the potential barrier between the photo-receiving device 61 and the floating diffusion region 64 becomes lower forming a charge transfer channel therebetween. Thus, the signal charges accumulated in the photo-receiving device 61 are transferred to the floating diffusion region 64 , and the potential of the floating diffusion region 64 varies in proportion to the amount of the signal charges transferred thereto. As a result, the drive voltage φDG applied to the drive gate DG decreases below the initial reference potential VFD, so that the signal data voltage Vpix appears at the output node Vout from the time t 3 .
At time t 4 in the second signal output phase Td 2 (t 3 ˜t 6 ), the first selection voltage φSG 1 is removed (i.e., inactivated) to float the transfer gate TG.
A second selection voltage φSG 2 is further applied to the selection gate SG at the time t 5 . Then, as the second selection voltage φSG 2 is conducted also to the boosting gate BG as the boosting voltage φBG, the resulting boosting gate-coupling voltage φCBG is added to the floated transfer gate TG around the time t 5 . As a result, the signal charges remaining in the photo-receiving device 61 are transferred to the floating diffusion region 64 . The second selection voltage φSG 2 is then removed from the selection gate SG at the time t 6 .
The reference voltage Vref is sampled in the first signal output phase Td 1 after the time t 2 and the signal data voltage Vpix is sampled in the second signal output phase Td 2 after the time t 5 , so that an image signal is output from the difference value Vsig between the sampled reference voltage Vref and signal data voltage Vpix.
The waveforms shown in FIG. 6B are just illustrative examples, and the dimensions of the signals and voltages and their settling times may be properly variable in various other manners. For example, in the operation of the image sensor having pixels characterized by FIGS. 6A and 6B , the transfer voltage may be applied to the transfer gate TG at the time t 4 or between the time t 4 and the time t 5 , and removed at the time t 5 . Further, the second transfer voltage φSG 2 may be applied thereto between the time t 3 and the time t 4 .
FIG. 7A is a schematic diagram of a pixel in an image sensor having a plurality of pixels having the structure shown in FIGS. 5A through 5C , and FIG. 7B is a waveform diagram of signals of the pixel of FIG. 7A illustrating the operation of the pixel the image sensor shown in FIG. 7A .
Referring to FIGS. 7A and 7B , during the first signal output phase Td 1 (t 0 ˜t 3 ) the first selection voltage φSG 1 is applied to the selection gate 79 , and the reset transistor RG is turned ON to generate the reference voltage at the output node Vout. At the beginning (the time t 3 ) of the second signal output phase Td 2 (t 3 ˜t 6 ), the transfer voltage φTG is applied to the transfer gate TG. Thus, the signal charges stored in the photo-receiving device 71 are transferred to the floating diffusion region 74 , so that the signal data voltage Vpix starts appearing at the output node Vout. During the term of t 5 ˜t 6 in the second signal output phase Td 2 , the second selection voltage φSG 2 is additionally applied to the selection gate SG and the boosting gate BG is coupled with the second selection voltage φSG 2 as the boosting voltage φBG. As a result, since the boosting gate-coupling voltage φCBG generated by the boosting voltage φDBG is added to the drive gate DG, the potential of the floating diffusion region 74 goes to a higher level from the initial value by ΔV+ΔφCBG. Therefore, the dynamic range of the image sensor can be increased.
In the first exemplary embodiment aforementioned ( FIG. 2A ), the boosting gate may additionally be disposed over the drive gate 105 c with interposing the dielectric film (and electrically connected to the selection gate 105 d ). And, likewise, in the second embodiment aforementioned ( FIG. 5A ), the boosting gate may be also disposed over the transfer gate 105 c with an interposing dielectric film (and electrically connected to the selection gate 105 d ).
Moreover, in the first and second embodiments described above, the boosting gate may be also provided over the reset gate with an interposing dielectric film and connected to the selection gate. In this case, the boosting gate over the reset gate acts as a dummy gate without any bias voltage applied thereto.
A method of fabricating the image sensor including pixels having the structure shown in FIGS. 2A through 2C will now be described with reference to FIGS. 8A through 13A and 8 B through 13 B.
FIGS. 8A through 13A and 8 B through 13 B are sectional diagrams illustrating processing steps for fabricating the image sensor including pixels having the structure show in FIGS. 2A through 2C . FIGS. 8A through 13A are taken along the section line I-I of FIG. 2A and FIGS. 8B through 13B are taken along the section line II-II of FIG. 2A . The area shown throughout FIGS. 8A to 13B corresponds to a region of the pixel array, excluding a peripheral region including an analog capacitor, and so on. This embodiment is exemplarily practiced to form a CMOS image sensor with a P-type semiconductor substrate, and the pixel comprised of four transistors and a photodiode as the photo-receiving device, but various other embodiments of the invention may be practiced, forming other various CMOS image sensors or CCD image sensors by those skilled in the art, within the scope of the invention.
First, referring to FIGS. 8A and 8B , the processing steps of fabricating the image sensor according to an embodiment of the invention begin with preparing a semiconductor substrate 101 . The semiconductor substrate 101 may be provided by a wafer cut from Czochralski or float zone of single crystalline bulk silicon, including an epitaxial layer, a buried oxide film, or a doped region in order to improve the characteristic and construct a desired structure. For example, the semiconductor substrate 101 is a P-type substrate doped with impurities such as boron (B).
The field isolation film 103 is formed to confine (isolate) active regions 102 ( 102 A and 102 B). The active region 102 A is provided to form the photo-receiving device (e.g., photodiode) of one pixel. The active region 102 B is provided to form various transistors (e.g., four transistors) of the pixel for transferring the signal charges generated from the photo-receiving device, converting the signal charges into the (pixel) signal data voltage Vpix, and outputting the (pixel) signal data voltage Vpix. The field isolation film 103 may be formed by means of a well-known technique, e.g., by shallow trench isolation (STI).
Referring to FIGS. 8A and 8B , a gate insulation film 104 , a first conductive film 105 , a dielectric film 107 , and a second conductive film 109 (comprising patterned portion 109 a shown in FIGS. 9A and 9B ), are deposited sequentially (e.g., by known methods). The gate insulation film 104 may be deposited by a thermal oxidation process for example. The first conductive film 105 may be formed of a doped polysilicon, for example. The first conductive film 105 (e.g., “gate poly”) is provided for forming the gates constructing the (four) transistors of each pixel in the pixel array area. (And, the first conductive film 105 is also used for the bottom electrode of a capacitor in the peripheral circuit area, not shown). The dielectric film 107 (e.g., a high-dielectric film) may be formed of an oxide-nitride-oxide (ONO) film by depositing an oxide film, a nitride film, and an oxide film, in that order. The second conductive film 109 (comprising patterned boosting gate portion 109 a shown in FIGS. 9A and 9B ) may be formed of a doped polysilicon (e.g., “gate poly”) or a metal. The second conductive film 109 is provided for forming (patterning) the boosting gate (pattern) in the pixel array area. The second conductive film 109 may also be used to form the top electrode of a capacitor in the peripheral circuit area (not shown).
Next, referring to FIGS. 9A and 9B , a photolithography and etching process is carried out to form (pattern) the boosting gate (pattern) 109 a from the second conductive film 109 . (Meanwhile, the top electrode of the capacitor is formed in the peripheral circuit area (not shown)). The photolithography process is conducted to form a photoresist pattern 110 a on the second conductive film 109 . With the photoresist pattern 110 a used as an etch mask, a portion of the second conductive film 109 is etched away to leave (form, pattern) the boosting gate (pattern) 109 a within the pixel array area (and the top electrode of the capacitor in the peripheral circuit area, not shown).
Referring to FIGS. 10A and 10B , a photolithography and etching process is carried out to form (pattern) the transfer gate 105 a, the reset gate 105 b, the drive gate 105 c, and the selection gate 105 d, from the first conductive film 105 . The transfer gate 105 a is aligned under the boosting gate 109 a. (Meanwhile, in the peripheral circuit area, the dielectric film and bottom electrode of the capacitor are formed.) The photolithography process is conducted to form photoresist patterns 110 b 1 , 110 b 2 , 110 b 3 , and 110 b 4 on the dielectric film 107 . Here, the photoresist pattern 110 b covers the boosting gate (pattern) 109 a, and defines the transfer gate 105 a. The photoresist patterns 110 b 2 , 110 b 3 , and 110 b 4 define the reset gate 105 b, the drive gate 105 c, and the selection gate 105 d, respectively. (Meanwhile, in the peripheral circuit area (not shown), the dielectric film and the first conductive film 105 , are selectively etched away by means of the photoresist patterns 110 b 1 ˜ 110 b 4 as etch masks.
Then, (referring to FIGS. 11A and 11B ), after forming an ion implantation mask (not shown, the ion implantation mask is formed to uncover the active region 102 A) for forming N-type regions of the photodiode, N-type ionic impurities are injected into the active region 102 A to form the N-type region 111 of the photodiode as the photo-receiving device. The N-type region 111 is disposed at one side of the transfer gate 105 a.
After forming an ion implantation mask (not shown, during this process, the ion implantation mask is formed to uncover the active region 102 A) for forming a P-type region of the photodiode, P-type ionic impurities are injected into the N-type region 111 of the active region 102 A to form the P-type region 113 of the photodiode as the photo-receiving device. As a result, the N-type and P-type regions, 111 and 113 , constitute the photodiode 115 .
For the purpose of preventing the signal charges, which are generated in the N-type region 111 of the photodiode 115 , from leaking into the P-type substrate 103 , after forming an N-type epitaxial silicon layer, a P-type well as a barrier layer may be formed to be interposed between the P-type substrate 103 and the N-type epitaxial silicon layer. The processing steps of forming the N-type epitaxial silicon layer and the P-type well are carried out before depositing the gate oxide film after completing the field isolation process.
An N-type ionic impurity implantation process is carried out to form N-type impurity diffusion regions (e.g., 117 , 119 , 121 , 123 ) between adjacent gates in the substrate 103 . The impurity diffusion region between the transfer gate 105 a and the reset gate 105 b functions as the floating diffusion region 117 . The impurity diffusion region between the reset gate 105 b and the drive gate 105 c functions as the reset diffusion region 119 RD. And, the impurity diffusion regions between the drive gate 105 c and the selection gate 105 d, and between the selection gate 105 d and the field isolation film 103 , function as source and drain regions 121 and 123 (of transistors SG and DG, see FIG. 6A ).
Next, referring to FIGS. 12A and 12B , after dielectric spacers are formed on sidewalls of the gates as an optional process, an interlevel insulation film 125 is deposited on the resultant structure. The interlevel insulation film 125 may be formed using a well-known film deposition process, e.g., being made of an insulation film of an oxide group.
Then, the interlevel insulation film 125 is patterned to form a contact hole 127 a disclosing the boosting gate (pattern) 109 a, a contact hole 127 b disclosing the floating diffusion region 117 , a contact hole 127 c disclosing the drive gate 105 c, and a contact hole 127 d disclosing the selection gate 105 d. Although not shown, contact holes disclosing the transfer and reset gates may be formed at the same time with the contact holes 127 a ˜ 127 d.
And, referring to FIGS. 13A and 13B , a conductive material (i.e., metal) film 131 is deposited on the interlevel insulation film 125 to fill up the contact holes 127 a ˜ 127 d. A photography and etching process is carried out upon the conductive material film 131 , forming local metal interconnection lines including local metal interconnection line 13 la that electrically connects the boosting gate 109 a with the selection gate 105 d through contact plugs 129 a and 129 d in the contact holes 127 a and 127 d, and local metal interconnection line 131 b that electrically connects the floating diffusion region 117 with the drive gate 105 c through contact plugs 129 b and 129 c in the contact holes 127 b and 127 c. During this process, contact plugs filling up the contact holes disclosing the transfer and reset gates may be formed.
Subsequently, usual processing steps are performed for completing the architecture of the CMOS image sensor, e.g., those of forming metal lines to apply control voltages to the local metal interconnection lines and contact plugs.
Another method of fabricating the image sensor according to another embodiment of the invention t is similar to that by the last described method embodiment, except that the boosting gate is formed over the drive gate (see FIGS. 5A to 5C ). In this case, the boosting gate over the drive gate is electrically connected to the selection gate.
Although the present invention has been described in connection with the exemplary embodiments of the present invention illustrated in the accompanying drawings, it is not limited thereto. It will be apparent to those skilled in the art that various substitution, modifications and changes may be thereto without departing from the scope and spirit of the invention.
According to the features of the invention described above, the boosting gate is disposed over the transfer gate and/or the drive gate with an interposing dielectric film, and is electrically connected to the selection gate. Therefore, when the selection voltage is applied to the selection gate (e.g., after floating the transfer gate), it is possible to enhance the transfer efficiency of the signal charges generated in the photo-receiving device because the floated transfer gate is coupled with a predetermined voltage having the effect of capacitive self-boosting.
Moreover, the dynamic range of the image sensor may be increased or adjusted, since the electrostatic potential floating diffusion region is variable. | Disclosed is a image sensor (e.g., a CMOS image sensor) including pixels each having a transfer transistor and a drive transistor, in which the gate of at least one of the transistors has a boosting gate disposed over it comprised of a conductive film pattern with interposing an insulation film. Thus, a voltage applied to the boosting gate is capacitively coupled to at least one of the transfer gate of the transfer transistor and a drive gate of the drive transistor. The transfer gate is supplied with the sum of the transfer voltage and the boosting gate-coupling voltage as a result and there is no need for providing a high voltage generator for the image sensor. The dynamic range of operation may be enhanced if such a coupling voltage is applied to the drive gate of the drive transistor. | 7 |
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of U.S. Provisional Application No. 61/739,506 filed on Dec. 19, 2012, entitled “Truck Trunk.” The above identified patent application is herein incorporated by reference in its entirety to provide continuity of disclosure.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to pickup truck cargo areas and divider assemblies therefor. More specifically, the present invention pertains to a modular, T-shaped assembly that operably separates the cargo area into two or three distinct zones without requiring tools or a permanent installation.
[0004] Pickup trucks are well known vehicles in the art that provide users with the ability to carry bulky items in an open cargo area behind the cab of the vehicle, or further to tow a trailer vehicle therebehind. These vehicles are invaluable to many trades and industries, and also provide individuals with a way to transport or haul items from one location to another with greater ease. Most modern trucks include an open cargo area with raised sides, a tailgate door that allows entry into the cargo area or closure thereof, and various tie down points around the cargo area for securing cargo therein.
[0005] One commonly recognized problem in the art that has various solutions is hauling relatively loose articles within an open pickup truck cargo area. During transport, articles that are not sufficiently supported will move around in the cargo area as the vehicle is maneuvering and changes in momentum are imparted into the cargo area items. Many times a user will secure the items using a series of tie-downs or haul loose items within the cab of the vehicle. However this is not always convenient, and given the quantity or relative size of the loose items, hauling the items inside the cab may not be possible.
[0006] The present invention is related to an organizational structure that divides the cargo area into distinct zones that can be increased or decreased based on the cargo being hauled. The assembly supports the items within a more confined area such that the items can bear against the assembly during vehicle transport rather than sliding across the cargo area and causing damage to the same or to the items themselves. By breaking down the area and confining articles to a smaller zone, the items can be more statically secured therein or at least preventing from sliding across an entirely open cargo area when being transported.
[0007] Various assemblies exist in the art for securing cargo items while being hauled in a pickup truck. While these assemblies may be useful, it is submitted that the present invention provides a more readily adaptable assembly that is easy to install and adjust in the cargo area. The assembly comprises a T-shaped assembly comprised of a first, laterally extending member, and second, longitudinally extending member. The first and second member are operably secured to one another and each may be telescopically adjustable in length, whereby the first member extends across the cargo area and bears into the sides of a pickup truck cargo area, while the second member is extended outward in length to abut against the forward or rear surface of the cargo area. The end caps of the laterally extending first member are simple bumper ends or are used to control the overall length of the member, as provided by the given embodiment disclosed below. The assembly divides the cargo area into either a two-zone configuration or a three-zone configuration, wherein each zone can be resized depending on the cargo for optimal support thereof.
[0008] 2. Description of the Prior Art
[0009] Devices have been disclosed in the prior art that relate to cargo support assemblies and cargo area dividers. These include devices that have been patented and published in patent application publications, and generally relate to sliding barriers that rely on rails or other structure for operation. The devices in the art fail to anticipate a modular, T-shaped divider that can expand or separate while deploying as a cargo area divider. The following is a list of devices deemed most relevant to the present disclosure, which are herein described for the purposes of highlighting and differentiating the unique aspects of the present invention, and further highlighting the drawbacks existing in the prior art.
[0010] One such device in the prior art is U.S. Pat. No. 6,267,427 to Ziehl, which discloses a pickup truck cargo bed partitioning device that is indexed to the wheel wheels within the cargo bed. The device comprises a planar base positioned between the two wheel wheels, along with at least one partitioning panel that is positioned to the sides of the planar base and hingedly connected thereto. If two partitioning panels are utilized, the panels can be engaged with an attachment strap when the panels are angled upwards via the hinge, whereby the panels rest against the wheel wheels and are secured together across the planar base by the strap. The Ziehl device, while disclosing a novel bed partition, relies on the wheel wheels as a means to stabilize the assembly and to properly function. The preset invention is suited to be setup along either end of the bed for partitioning the same using a T-shaped partition assembly adaptable to fit any sized cargo bed within its extendable limits.
[0011] Another device in the prior art is U.S. Pat. No. 6,827,533 to Cano-Rodriguez, which discloses a cargo retention device and method for retaining cargo in the bed of a pickup truck that comprises a first and second extension member that form a T-shaped device. The members are extended outward to secure against the inner walls of the cargo bed of the truck, whereby the assembly can be locked into place to reduce the open area in the cargo bed. This acts to retain articles in the bed that do no consume its entire area, thereby preventing shifting of the same. Several accessories are provided, along with different embodiments of the extension members. However, the Cano-Rodriguez device is only adapted to operate in a single vertical plane. The present invention is adapted to create a first and second partition using a single cross member and a perpendicular member that forms an extendable T-shape cargo divider.
[0012] U.S. Pat. No. 6,206,624 to Brandenburg is another device that discloses a cargo space divider for the bed of a pickup that partitions the bed into smaller segments using suspended sectional walls that span the width of the bed. The sectional walls are suspended from support rails that rest on the upper rails of the cargo bed and extend laterally thereacross. Longitudinal sectional walls are utilized between pairs of laterally disposed sectional walls to further subdivide the cargo area as necessary. While providing a potentially T-shaped partitioning assembly, the Brandenburg assembly is comprised of elements that diverge in design and application. The present invention rests along the bed of the cargo area and is extended to bear into the sidewalls thereof, while the Brandenburg device is supported by the upper rails of the cargo area and extends the partitions downward.
[0013] Similar to the Brandenburg device is U.S. Pat. No. 6,629,807 to Bernardo and U.S. Pat. No. 8,100,615 to Freeborn. The Bernardo device comprises a cargo barrier that is slidable relative to the front and back of the cargo bed of a pickup truck by way of a track system that spans the upper rails of the cargo bed. A divider is slidably positioned along the track system to partition the cargo area into smaller areas. The Freeborn device provides a similar structure that comprises a sliding gate that is positionable across a cargo area of the pickup truck, whereby the gate is supported by slide rails. The structural arrangement is different from Bernardo; however the concept is the same. A cargo divider is slidably positioned along side rails in the cargo area.
[0014] The present invention contemplates a T-shaped partition that is placed along the bed of a pickup truck cargo area, whereby the partition includes extendable members that are adapted to expand to the dimensions of the given cargo area. The assembly utilizes a first member that functions as a main cross member across the cargo area. The first member includes a tongue and groove arrangement with a perpendicular second member that functions as a secondary partition member, whereby the second member is slidable therealong and lockable in a desired location along the cross member groove. End cap members on the first member and the perpendicular second member allow the assembly to bear against the truck bed interior without causing damage thereto, while retaining the position of the assembly therein while segregating cargo.
[0015] It is submitted that the present invention is substantially divergent in design elements from the prior art, and consequently it is clear that there is a need in the art for an improvement to existing cargo area divider assemblies. In this regard the instant invention substantially fulfills these needs.
SUMMARY OF THE INVENTION
[0016] In view of the foregoing disadvantages inherent in the known types of pickup truck cargo area dividers, partitions, and tie down systems now present in the prior art, the present invention provides a new divider system that can be utilized for providing convenience for the user when operably partitioning the cargo area of the pickup using a T-shaped assembly resting on the bed thereof.
[0017] It is therefore an object of the present invention to provide a new and improved cargo area divider assembly that has all of the advantages of the prior art and none of the disadvantages.
[0018] It is another object of the present invention to provide a cargo area divider assembly that includes a first and second member forming a T-shaped assembly that partitions the cargo area of a pickup truck into at least two distinct zones.
[0019] Another object of the present invention is to provide a cargo area divider assembly that is extendable such that the assembly can be deployed on any sized truck cargo area and partition the same.
[0020] Yet another object of the present invention is to provide a cargo area divider assembly that requires no tools to install and can readily be removed and stowed when not required.
[0021] Another object of the present invention is to provide a cargo area divider assembly that utilizes a first member in a removably slidable connection with a second member, wherein the connection comprises a tongue and groove attachment.
[0022] Another object of the present invention is to provide a cargo area divider assembly that can be locked into a static position in the cargo area and is stabilized by bearing into the cargo area upstanding surfaces for support.
[0023] Another object of the present invention is to provide a cargo area divider assembly that does not require alteration of the existing cargo area or any installation elements therein prior to deployment.
[0024] A final object of the present invention is to provide a cargo area divider assembly that may be readily fabricated from materials that permit relative economy and are commensurate with durability.
[0025] Other objects, features and advantages of the present invention will become apparent from the following detailed description taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTIONS OF THE DRAWINGS
[0026] Although the characteristic features of this invention will be particularly pointed out in the claims, the invention itself and manner in which it may be made and used may be better understood after a review of the following description, taken in connection with the accompanying drawings wherein like numeral annotations are provided throughout.
[0027] FIG. 1 shows an embodiment of the first member of the present divider assembly, which acts as the main cross member disposed across the cargo area.
[0028] FIG. 2 shows end views of the two telescopic portions of the first member, wherein the first includes a groove and the second is open ended to accept the first portion therein.
[0029] FIG. 3 shows side and overhead views of the second member of the divider assembly, wherein the second member is a perpendicular partition slidably connected to the first member.
[0030] FIG. 4 shows the first contemplated embodiment of the divider assembly of the present invention in a working state, along with one of the member end caps in an exploded state.
[0031] FIG. 5 illustrates the tongue and groove connection between the first and second member of the divider assembly.
[0032] FIG. 6 shows the divider assembly in a working state, deployed along the bed of a pickup truck cargo area to partition the same into three distinct zones.
[0033] FIG. 7 shows a perspective view of a second embodiment of the divider assembly of the present invention.
[0034] FIG. 8 shows a view of the elongated divider wall of the second embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0035] Reference is made herein to the attached drawings. Like reference numerals are used throughout the drawings to depict like or similar elements of the pickup truck cargo area divider assembly. For the purposes of presenting a brief and clear description of the present invention, two embodiments will be discussed as used for partitioning a pickup truck cargo area into smaller, discrete zones for containment of smaller articles or loose cargo items therein. The figures are intended for representative purposes only and should not be considered to be limiting in any respect.
[0036] Referring now to FIG. 1 , there is shown a side view of the laterally extending first member of the cargo area divider system of the present invention. The first member acts as a main cross member adapted to be placed laterally across a pickup truck bed (or longitudinally, depending on user choice), wherein a second, perpendicular member engages the first member to form a T-shaped assembly. The first member comprises an elongated length having a first 11 and second 12 portion in telescopic relationship with one another to operably control the elongated length of the first member. The first portion 11 comprises an elongated, open-interior portion having a closed outer end 16 and an open interior end 13 that is adapted to accept the second portion 12 therein. Along the length of the first telescopic portion 11 is a purity of fastener locations 14 therealong. The fastener locations 14 are adapted to accept a pin or dowel therethrough for securing the first telescopic portion 11 to the second telescopic portion 12 , securing the two together to achieve a given overall member length that is fixed in nature.
[0037] The second telescopic portion 12 comprises an elongated length that is adapted to fit within the open first portion 11 . Along the side of the second telescopic portion 12 is an elongated groove 15 that extends from the outer end 17 thereof and up to the interior end 18 . The groove 15 is adapted to accept the tongue of the perpendicular second member therein such that the two are in a sliding relationship. Along the length of the second portion 12 is at least one fastener hole extending therethrough (not shown). This hole is adapted to align with the fastener holes 14 of the first telescopic member such that a pin can be slid therethrough to secure the first and second telescopic portions in a static state while deployed.
[0038] Along the outer ends 16 , 17 of the first member are end caps 20 that are comprised of a compressible material. The end caps 20 are utilized to fill the gap between the ends of the first member and the sides of the cargo area, wherein the extended length of the first member can be fixed to be just short of the cargo area width. The end caps 20 are compressed between the side surfaces of the cargo area and the first and second portion outer ends 16 , 17 such that the laterally extending first member is firmly positioned therebetween and will not readily move during transport. The caps 20 are fastened to the ends of the first member and prevent the ends from scratching against the walls of the cargo area when in use.
[0039] Referring now to FIG. 2 , there are shown end views of the first 11 and second 12 laterally telescoping portion and the first member. The first portion 11 comprises a rectangular cross section with an open interior 16 adapted to accept therein the second portion 12 . The first portion 11 comprises a pair of sidewalls, a base surface, an upper surface, and an outer end wall defining the open interior 16 . The second portion 12 comprises a solid member 17 having an elongated groove or channel 15 extending therealong. The groove 15 is adapted to secure the tongue of the perpendicular member and allow slidable positioning thereof relative to the second portion 12 . The outer ends of both the first 11 and second 12 portion also include fastener holes 21 to accommodate the fasteners of the end caps.
[0040] Referring now to FIG. 3 , there is shown a side view and overhead view of the perpendicular member 30 of the present invention. The perpendicular member 30 comprises a first end that includes an outwardly extending tongue element 34 , and a second end 38 that extends outward to provide a widened end 32 . The tongue element 34 is designed to be accepted by the groove of the second portion of the laterally extending member, while the widened end 32 is adapted to bear against an interior surface of the cargo area. This end may include cushioning elements 39 , bumper elements, or end caps as provided on the laterally extending member. Furthermore, the construction of the perpendicular member 30 may take on two forms: a length adjustable form and a static form.
[0041] The length adjustable form of the perpendicular member is shown in FIG. 3 and comprises a pair of perpendicular telescoping portions. As provided in the laterally extending member, a first perpendicular portion 33 is accepted into the open interior of a second perpendicular portion 41 to allow the two portions to slide relative to one another and be fastened 37 together via aligned fastener holes 40 . The end 31 of the first telescoping member is open and accepts the end 36 of the second telescoping member, wherein the two are in a sliding relationship to dictate the overall length of the perpendicular member 30 .
[0042] Referring now to FIG. 4 , there is shown a perspective view of the complete assembly, wherein the first embodiment of the present invention is illustrated. The laterally extending member, comprising of the first portion 11 and second portion 12 , is connected to the perpendicular member 30 to form a T-shaped divider. The tongue element 34 of the perpendicular member 30 is secured within the channel 15 of the laterally extending member, and the length of both the telescoping perpendicular member and laterally extending member is fixed using a plurality of fasteners 37 , pins, or dowels. When installed within a cargo area, the length of each member is extended outward toward the interior surfaces thereof. The lengths are fixed, wherein the ends 17 , 16 , 38 of the assembly are abutted against or positioned adjacent to the cargo area interior surfaces. The fastened 50 end caps 20 and the cushioning elements are used to provide a secure fitment and prevent marring of the cargo area interior surfaces.
[0043] Referring now to FIG. 5 , there is shown a view of the connection between the laterally extending member and the perpendicular member. The user has the option of deploying the present invention as a single divider (i.e. the laterally extending first member only), or alternatively as a T-shaped divider assembly by connecting the laterally extending first member to the perpendicular second member. When installed, the sidewall surfaces of the members provide an upstanding barrier against moving cargo, wherein the cargo can be placed into a space within the cargo area that has been subdivided into smaller areas by the assembly.
[0044] As shown in FIG. 5 , the contemplated connection between the two members is a tongue and groove, slidable attachment. The tongue member 34 of the perpendicular member 30 slides into the channel 15 of the laterally extending member via its outer end 17 . The channel 15 extends through the outer end 17 such that the two members can be coupled together and the perpendicular member can slide freely within the channel 15 thereafter.
[0045] Referring to FIG. 5 , there is illustrated a view of the first embodiment of the present invention in a working state. The first 11 and second portions 12 of the laterally extending first member are fixed to one another, while the end caps 20 thereof bear against the upstanding walls 101 of the vehicle cargo area 100 . The perpendicular member 30 extends from the laterally extending first member, wherein both rest upon the base surface 102 of the cargo area. The outer end of the perpendicular member is adapted to abut against the cargo door 104 interior surface 103 when the door 104 is in a closed state. This separates the cargo area 100 into three distinct zones. The user has the option of removing the perpendicular second member to divide the cargo area 100 into two distinct zones, if desired.
[0046] Referring now to FIGS. 7 and 8 , there is shown a second embodiment of the present invention. In this embodiment, the laterally extending first member 62 comprises a fixed length and a unitary structure. The length adjustment of this member 62 is accomplished using a first and second slidable end member 61 , which are in a slidable and telescoping relationship with the first member 62 . The end members 61 are fixed thereto via fasteners or pins placed through aligned fastener holes 64 , 14 in the first member 62 ends and the end members 61 themselves.
[0047] The second embodiment of the first member 62 comprises an elongated channel 15 in the same manner as the first embodiment, wherein the tongue member 34 of a perpendicular member 30 is accepted therein. The channel 15 extends to the ends 63 of the first member 62 or alternatively terminates at a widened channel area 65 adapted to allow the tongue to be freely removed from the channel 15 . This widened channel area 65 is preferably positioned along the end or ends 63 of the first member 62 , wherein the end members 61 secure over the widened channel area 65 while the assembly is in use. This prevents the tongue member 34 from exiting the channel 15 while the end members 61 are attached to the first member 62 . The end members 61 comprise an open end, an enclosed outer end, and an interior volume adapted to accept one end 63 of the first member 62 therein. The end members 61 are slidable with respect to the first member 61 and are fixed thereto, establishing the overall length of the assembly across the cargo area.
[0048] Vehicles, such as trucks and cargo vans are useful for transporting large items that will not fit within a conventional vehicle. Users of such vehicles often experience items sliding around in the bed during transit. It can be very difficult to keep items organized in this situation, causing a user to spend unnecessary time sorting through things upon arrival. Furthermore, the items may fall over or collide, either of which can result in breakage and other damage thereto. Overall, the present invention provides an apparatus to prevent cargo from sliding in the cargo area of a vehicle. The assembly comprises two embodiments that include telescoping members that spans the width of the cargo area and include a perpendicular member to divide the cargo area into three distinct zones using a T-shaped assembly. The assembly sections off a portion of the pickup truck bed, which helps to secure cargo contained therein. The assembly adjusts to suit beds and loads of various sizes, and enables fast, simple installation and removal thereof.
[0049] It is submitted that the instant invention has been shown and described in what is considered to be the most practical and preferred embodiments. It is recognized, however, that departures may be made within the scope of the invention and that obvious modifications will occur to a person skilled in the art. With respect to the above description then, it is to be realized that the optimum dimensional relationships for the parts of the invention, to include variations in size, materials, shape, form, function and manner of operation, assembly and use, are deemed readily apparent and obvious to one skilled in the art, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the present invention.
[0050] Therefore, the foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention. | A pickup truck cargo area separator is provided that operably divides the cargo area of a pickup truck into distinct segments using slidably adjustable members. A first member is positioned laterally across a pickup truck cargo area, while a second member slidably connects to the first member to form a T-shaped divider assembly. The T-shaped assembly separates the cargo area into three defined zones. The members are lengthwise adjustable using a telescoping construction and are lockable in a static state once deployed, wherein the members abut against the interior surfaces of the cargo area to remain in place during use. End caps positioned on the lateral member ensure a tight fitment thereof across the cargo bed, while the height of the members act as internal barriers within the cargo area for confining cargo items in specific zones during transport. | 1 |
BACKGROUND OF THE INVENTION
[0001] The configuration of a solid material workpiece can be altered by processes in which material is removed from the workpiece, in which the workpiece is separated into multiple pieces with or without the removal of material, or in which the shape of the workpiece is altered without any significant material removal. Exemplary shaping processes include, for example, machining/turning, grinding, drilling, tapping, sawing, milling, and planing. In these shaping processes, material is removed from the workpiece during the process. In a forming process, the shape, thickness, diameter, or any other physical configuration of the workpiece is altered without any significant material removal, or the workpiece is separated into multiple pieces without any significant material removal. Typical forming processes include, for example, extruding, stamping, profiling, bending, slitting, shearing, drawing, forging, and punching. Any of these processes can be applied to solid metallic or non-metallic materials.
[0002] Forming processes are characterized by forcible contact of a tool with the workpiece in which the tool deforms the workpiece. In the process, external heat is generated by surface friction between the tool and the workpiece, and internal heat is generated by deformation of the workpiece material. In order to prevent overheating of the tool and workpiece, a coolant or a combined lubricant/coolant fluid such as a water-oil emulsion can be applied to the tool and/or workpiece. The cooling and lubrication properties of a coolant/lubricant fluid are critical in decreasing tool wear and extending tool life. Cooling and lubrication also are important in achieving the desired size, finish, and shape of the workpiece. A secondary function of the coolant/lubricant may be to prevent marring of the finished surface. Various additives and surfactants can be added to the coolant and lubricant fluids to enhance performance. In certain applications, particularly metalworking applications, cryogenic fluids are used to provide effective cooling.
[0003] These processes have been well-developed and are widely used on metals, plastics, and other materials in various manufacturing industries. While the art of forming of materials is well-developed, there remains a need for further innovation and improvements in forming processes. This need is addressed by the embodiments of the present invention as described below and defined by the claims that follow.
BRIEF SUMMARY OF THE INVENTION
[0004] An embodiment of the invention relates to a method of forming a workpiece comprising (a) providing a tool and a workpiece, wherein the workpiece has an initial shape; (b) placing the workpiece and the tool in contact, applying force to the tool and/or the workpiece, and moving the tool and/or the workpiece to effect a change in the initial shape of the workpiece by forming; and (c) providing a jet of cryogenic fluid and impinging essentially all of the jet of cryogenic fluid on a surface of the tool.
[0005] The workpiece may be plastically deformed by the tool. The workpiece may be separated into two or more pieces by the tool. A lubricant may be applied to any area on a surface of the tool and/or to any area on a surface of the workpiece. The lubricant may comprise a powder entrained in the jet of cryogenic fluid; alternatively, the lubricant may be a liquid sprayed onto the tool and/or workpiece in combination with impinging essentially all of the jet of cryogenic fluid on a surface of the tool. When a lubricant is used, the surface energy of the tool and/or the workpiece may be less than about 38 milliNewtons per meter (38 mN/m). The amount of lubricant applied to the tool and/or the workpiece may be less than about 100 milligrams per square foot. The lubricant may be a solid or semi-solid and the lubricant may be applied by pressing or smearing onto the tool and/or workpiece. The workpiece may comprise metal.
[0006] Typically, essentially no cooling of the workpiece is effected by impingement of the jet of cryogenic fluid on a surface of the tool. The cryogenic fluid may be selected from the group consisting of nitrogen, argon, carbon dioxide, and mixtures thereof.
[0007] The forming method may be selected from the group consisting of contour and profile roll forming, power spinning, roll forging, orbital forging, shoe-type pinch rolling, alligator shearing, guillotine shearing, punch parting, rotary shearing, line shearing, slitting, wire and rod drawing, tube drawing, moving mandrel drawing, punch drawing, moving insert straightening, die and punch press bending, hammer forming, and die forging.
[0008] Another embodiment of the invention includes a method of forming a workpiece comprising (a) providing a tool and a workpiece, wherein the workpiece has an initial shape; (b) placing the workpiece and the tool in contact, applying force to the tool and/or the workpiece, and moving the tool and/or the workpiece to effect a change in the initial shape of the workpiece by forming; and (c) providing a jet of cryogenic fluid and impinging at least a portion of the jet of cryogenic fluid on a surface of the tool while impinging essentially none of the jet of cryogenic fluid on the workpiece.
[0009] An alternative embodiment of the invention relates to a method of forming a workpiece comprising (a) providing a tool and a workpiece, wherein the workpiece has an initial shape; (b) placing the workpiece and the tool in contact, applying force to the tool and/or the workpiece, moving the tool and/or the workpiece to effect a change in the initial shape of the workpiece by forming; (c) providing a jet of cryogenic fluid and impinging at least a portion of the jet of cryogenic fluid on a surface of the tool; and (d) terminating contact of the tool and workpiece; wherein the geometric average temperature of the tool may be less than the geometric average temperature of the workpiece. The forming method may be selected from the group consisting of contour and profile roll forming, power spinning, roll forging, orbital forging, shoe-type pinch rolling, alligator shearing, guillotine shearing, punch parting, rotary shearing, line shearing, slitting, wire and rod drawing, tube drawing, moving mandrel drawing, punch drawing, moving insert straightening, die and punch press bending, hammer forming, and die forging.
[0010] Another alternative embodiment of the invention includes a shaped article made by a method comprising (a) providing a tool and a workpiece, wherein the workpiece has an initial shape; (b) placing the workpiece and the tool in contact, applying force to the tool and/or the workpiece, and moving the tool and/or the workpiece to effect a change in the initial shape of the workpiece by forming; (c) providing a jet of cryogenic fluid and impinging essentially all of the jet of cryogenic fluid on a surface of the tool; and (d) forming the workpiece into a final shape to provide the shaped article.
[0011] A related embodiment of the invention includes a shaped article made by a method comprising (a) providing a tool and a workpiece, wherein the workpiece has an initial shape; (b) placing the workpiece and the tool in contact, applying force to the tool and/or the workpiece, and moving the tool and/or the workpiece to effect a change in the initial shape of the workpiece by forming; (c) providing a jet of cryogenic fluid and impinging at least a portion of the jet of a jet of cryogenic fluid on a surface of the tool while impinging essentially none of the jet of cryogenic fluid on the workpiece; and (d) forming the workpiece into a final shape to provide the shaped article.
[0012] Another related embodiment relates to-a shaped article made by a method comprising (a) providing a tool and a workpiece, wherein the workpiece has an initial shape; (b) placing the workpiece and the tool in contact, applying force to the tool and/or the workpiece, moving the tool and/or the workpiece to effect a change in the initial shape of the workpiece by forming; (c) providing a jet of cryogenic fluid and impinging at least a portion of the jet of cryogenic fluid on a surface of the tool; and (c) forming the workpiece into a final shape to provide the shaped article; and terminating the contact of the tool and the shaped article; wherein the geometric average of the temperature of the tool may be less than the geometric average of the temperature of the shaped article.
[0013] A final embodiment of the invention relates to an apparatus for processing a workpiece comprising (a) a tool and a workpiece, wherein the workpiece has an initial shape; (b) means for placing the workpiece and the tool in contact to form an interface, means for applying force to the tool and/or the workpiece, and means for moving the tool and/or the workpiece to effect a change in the initial shape of the workpiece; and (c) a cryogenic fluid application system adapted for providing a jet of cryogenic fluid and impinging essentially all of the jet of cryogenic fluid on a surface of the tool. The forming apparatus may be selected from the group consisting of contour and profile roll forming systems, power spinning systems, roll forging systems, orbital forging systems, shoe-type pinch rolling systems, alligator shearing systems, guillotine shearing systems, punch parting systems, rotary shearing systems, line shearing systems, slitting systems, wire and rod drawing systems, tube drawing systems, moving mandrel drawing systems, punch drawing systems, moving insert straightening systems, die and punch press bending systems, hammer forming systems, and die forging systems.
BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS
[0014] FIG. 1A is a schematic diagram of the splash pattern of a water or oil-based coolant stream that impinges on a target surface.
[0015] FIG. 1B is a schematic diagram of the splash pattern of a cryogenic fluid coolant stream that impinges on a target surface.
[0016] FIG. 2A is a schematic diagram of a contour and profile roll forming system illustrating the location of cryogenic fluid application according to an embodiment of the invention.
[0017] FIG. 2B is a schematic diagram of a power spinning system prior to workpiece deformation illustrating the location of cryogenic fluid application according to an embodiment of the invention.
[0018] FIG. 2C is a schematic diagram of a power spinning system following workpiece deformation illustrating the location of cryogenic fluid application according to an embodiment of the invention.
[0019] FIG. 3 is a schematic diagram of a roll forging system illustrating the location of cryogenic fluid application according to an embodiment of the invention.
[0020] FIG. 4 is a schematic diagram of an orbital forging system illustrating the location of cryogenic fluid application according to an embodiment of the invention.
[0021] FIG. 5 is a schematic diagram of a shoe-type pinch rolling system illustrating the location of cryogenic fluid application according to an embodiment of the invention.
[0022] FIG. 6 is a schematic diagram of an alligator shearing system illustrating the location of cryogenic fluid application according to an embodiment of the invention.
[0023] FIG. 7 is a schematic diagram of a guillotine shearing system illustrating the location of cryogenic fluid application according to an embodiment of the invention.
[0024] FIG. 8 is a schematic diagram of a punch parting system illustrating the location of cryogenic fluid application according to an embodiment of the invention.
[0025] FIG. 9 is a schematic diagram of a rotary shearing system illustrating the location of cryogenic fluid application according to an embodiment of the invention.
[0026] FIG. 10 is a schematic diagram of a shearing line system illustrating the location of cryogenic fluid application according to an embodiment of the invention.
[0027] FIG. 11 is a schematic diagram of a slitting line system illustrating the location of cryogenic fluid application according to an embodiment of the invention.
[0028] FIG. 12 is a schematic diagram of a wire and rod drawing system illustrating the location of cryogenic fluid application according to an embodiment of the invention.
[0029] FIG. 13 is a schematic diagram of a tube drawing (sinking) system illustrating the location of cryogenic fluid application according to an embodiment of the invention.
[0030] FIG. 14 is a schematic diagram of a moving mandrel drawing system illustrating the location of cryogenic fluid application according to an embodiment of the invention.
[0031] FIG. 15 is a schematic diagram of a punch drawing system illustrating the location of cryogenic fluid application according to an embodiment of the invention.
[0032] FIG. 16 is a schematic diagram of a moving insert straightening system illustrating the location of cryogenic fluid application according to an embodiment of the invention.
[0033] FIGS. 17A, 17B , 17 C, and 17 D are schematic diagrams of die and punch press bending systems illustrating the locations of cryogenic fluid application according to an embodiment of the invention.
[0034] FIG. 18 is a schematic diagram of a hammer forming system illustrating the location of cryogenic fluid application according to an embodiment of the invention.
[0035] FIG. 19 is a schematic diagram of a die-forging system illustrating the location of cryogenic fluid application according to an embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0036] Forming operations modify the geometry of a work material or workpiece by plastic deformation and/or shearing under the contact stress of a tool sliding in some fashion over the surface of the work material or workpiece. This relative motion or sliding of the work material and the tool surfaces may result in localized heating, tool surface softening, wear, and seizures or fractures. Effective cooling of the surface and reduction of adhesive sticking between the tool and the work material have been recognized as critical for achieving high production rates., and the conventional solution involves application of lubricating coolants, oils, metallic soaps, and greases to the surfaces of the work material and the tool. The most frequently used lubricating media include straight and compounded oils with sulfur and chlorine, graphite, wax, fluorinated polymer additives, solvents, surfactants, phosphorus, molybdenum disulfide, and biocides. Typical examples of metal forming operations which involve these lubricating media include blanking, piercing, slitting, drawing, spinning, roll forming, and forging. Due to recently recognized negative effects of these lubricants on health, environment, and process economics, which increase costs of cleaning operations, it is desired to minimize or eliminate these lubricants.
[0037] The embodiments of the present invention eliminate or at least minimize the usage of lubricating media without affecting the conventional metal forming rate by replacing or augmenting them with completely innocuous, environmentally-friendly, and clean cryogenic gases. Although not lubricating, the cryogenic gases in the gas-phase, liquid-phase, and multi-phase form can cool the surface of the tool to the point at which the loss of tool hardness and increase in friction coefficient are arrested, and forming may be carried out more effectively than in the case of a completely dry operation. The effect of cooling on hardness, strength, and impact resistance of metals is increased because conductive and convective heat transfer is enhanced by the large temperature difference between the cryogenic cooling medium and the target material. Thus the embodiments of the invention utilize the impingement of a fast-moving cryogenic jet (or jets) on the surface of the forming tool while avoiding or minimizing contact of the cryogen with the work material. This allows the tool to retain the desired hardness and strength while the work material is free to soften and plastically flow or shear during forming.
[0038] In experimental work supporting development of the embodiments of the invention, it was discovered that an expanding cryogenic jet does not splash after impacting a tool surface, and as a result does not contact and cool the work material. This selective cooling of the tool but not the work material thus is possible by proper application of a cryogenic fluid using methods described herein. The methods may be applied to metal forming operations in which cryogenic coolant is aimed at the tool surface only such that the work material in proximity of the tool is not cooled significantly. Typically, the temperature of the work material is above the freezing point of water. In some embodiments, the geometric average temperature of the tool is less than the geometric average temperature of the work material or workpiece. In other embodiments, the geometric average temperature of the tool is above the geometric average temperature of the workpiece but below a temperature at which the tool properties (for example, hardness) are adversely affected.
[0039] The impingement of conventional and cryogenic fluid streams on the surface of a workpiece is illustrated in FIGS. 1A and 1B , respectively. In FIG. 1A , nozzle 1 discharges spray or jet 2 of a cooling liquid (typically at or near ambient temperature) that impinges upon surface 3 . The liquid may be water, oil, a water/oil emulsion, or other similar liquid. As the liquid impinges upon and cools the surface, splash zone 3 is formed and liquid droplets 5 are rejected outward from the splash zone. Some vaporization may occur in splash zone 3 , but the major portion of the coolant remains in the liquid phase. When surface 3 is a surface of a tool in contact with a workpiece (not shown), these droplets may fall on the workpiece and cool the workpiece.
[0040] In FIG. 1B , nozzle 6 discharges spray or jet 7 of a cryogenic fluid that impinges upon and cools surface 8 . An intense vaporization zone 9 is formed wherein essentially all cryogenic fluid that is in the liquid phase in the zone is vaporized, and no significant amount of unvaporized liquid is rejected outward from this zone. When surface 8 is a surface of a tool in contact with a workpiece (not shown), essentially no cooling of the workpiece is caused by residual cryogenic liquid rejected from the vaporization zone.
[0041] When lubricants are used in conjunction with cryogenic cooling of the tool, methods can be used to minimize the quantity of the lubricants. In one embodiment, microscopic quantities of oil mist may be co-sprayed toward the surface of the tool or toward the surfaces of both the tool and the work material while the cryogenic fluid is sprayed on the tool. Alternatively or additionally, finely-divided particles of lubricant material may be suspended in the cryogenic fluid sprayed on the tool surface. In another embodiment, microscopic quantities of solid lubricant may be smeared over the tool or both the tool and work material surfaces.
[0042] Due to recently-recognized negative effects of conventional lubricants on health, the environment, and process economics, the costs of operations to clean formed articles have increased significantly. It is desired, therefore, to reduce or eliminate these lubricants. The embodiments of the invention eliminate or at least minimize the use of lubricating media without affecting the conventional metal forming rate by using innocuous, environmentally-friendly, and clean cryogenic fluids in the forming process.
[0043] In the present disclosure, the term “forming” is defined as a process in which the shape of a workpiece or work material is changed by contact with a tool without the removal of material from the workpiece or without the removal of any significant amount of material from the workpiece. A very small and insignificant amount of material may be worn off the workpiece by friction between the tool and workpiece. In a forming process, in contrast with a shaping process, there is no deliberate removal of material from the workpiece by grinding, milling, planing, sawing, drilling, machining, and the like.
[0044] In the present disclosure, the term “cryogenic fluid” means a gas, a liquid, solid particles, or any mixture thereof at temperatures below about minus 100° C. Cryogenic fluids for use in embodiments of the present invention may comprise, for example, nitrogen, argon, carbon dioxide, or mixtures thereof. A lubricant is defined as any of various oily liquids and/or greasy solids that reduce friction, heat, and wear when applied to parts that are in movable contact. The lubricant may be essentially water-free, or alternatively may contain water. Exemplary lubricants for use in embodiments of the present invention include, but are not limited to, Quakerol-800, a lubricating fluid available from Quaker Chemical Corp.; Gulf Stainless Metal Oils produced by Gulf Lubricants; Rolube 6001 fluids for forming non-ferrous metals available from General Chemical Corp.; and a range of other, mineral, synthetic, or soluble oil fluids and wax suspensions formulated for forming, rolling, cutting, and grinding operations. Oil-water emulsions may be considered as lubricants when used in embodiments of the invention.
[0045] The terms “apply”, “applying”, or “applied” as used for a cryogenic fluid mean spraying, jetting, or otherwise directing the fluid to contact and cool any external surface of a tool while the workpiece and the tool are in contact. In a cyclic forming process, in which the tool and workpiece are in intermittent contact, the fluid also may be applied to the tool during at least a portion of the time period when there is no tool/workpiece contact. The terms “apply”, “applying”, or “applied” as used for a liquid lubricant mean spraying, jetting, flooding, misting, or otherwise directing the lubricant to contact the surface of a tool or workpiece and to penetrate and/or fill the microscopic regions formed by the surface asperities on the tool and/or workpiece. The terms “apply”, “applying”, or “applied” as used for a solid or semi-solid lubricant mean pressing, rubbing, smearing, or otherwise directing the solid lubricant to contact the surface of a tool or workpiece and to penetrate and/or fill the microscopic regions formed by the surface asperities on the tool and/or workpiece.
[0046] The term “surface” as used in reference to a tool or a workpiece means any external surface of the tool or workpiece. The term “area” as used in reference to a tool or a workpiece refers to a region on any external surface of the tool or workpiece.
[0047] When a jet of cryogenic fluid is applied to the surface of a tool, essentially all of the jet impinges on a surface of the tool. The term “essentially all” means that at least 90% of the fluid in the jet impinges on the tool surface. Essentially none of the jet of cryogenic fluid impinges on the workpiece. The term “essentially none” means that less that 10% of the jet of cryogenic fluid impinges on the workpiece. Essentially no cooling of the workpiece is effected by impingement of the jet of cryogenic fluid on the tool. The term “essentially no cooling” means that the geometric average temperature of the workpiece, which may be affected by small amounts of stray cryogenic fluid from the tool surface, changes by less than 10° C. due to contact with this stray cryogenic fluid.
[0048] The indefinite articles “a” and “an” as used herein mean one or more when applied to any feature in embodiments of the present invention described in the specification and claims. The use of “a” and “an” does not limit the meaning to a single feature unless such a limit is specifically stated. The definite article “the” preceding singular or plural nouns or noun phrases denotes a particular specified feature or particular specified features and may have a singular or plural connotation depending upon the context in which it is used. The adjective “any” means one, some, or all indiscriminately of whatever quantity. The term “and/or” placed between a first entity and a second entity means one of (1) the first entity, (2) the second entity, and (3) the first entity and the second entity.
[0049] The geometric average temperature of a workpiece is defined as an arithmetic average of the temperature at discrete points located on the workpiece surface (i.e., the portion of the workpiece surface that comes into contact with the tool surface) during a forming cycle averaged for the time length of the forming cycle.
[0050] The geometric average temperature of a tool is defined as an arithmetic average of the temperature at discrete points located on the work surface of the tool (i.e., the portion of the tool surface that comes into contact with the workpiece surface) during a forming cycle averaged for the time length of the forming cycle. For a rotating tool, the discrete points located on the work surface of the tool are the points located on and/or immediately near the perimeter of the tool, and the time length of the forming cycle is the time required for one full revolution of this tool. For an intermittently operating tool (for example, a punch, forming hammer, shearing blade, and the like), the discrete points located on the work surface of the tool are the points located on and/or immediately near the tool face that contacts the workpiece, and the time length of the forming cycle is the time required for moving in, contacting the workpiece, and withdrawing the tool from the workpiece.
[0051] The embodiments of the invention are based on the beneficial effect of cryogenic cooling to increase hardness and plastic flow resistance while reducing impact resistance of the tool material. Heat transfer required for cooling can be both conductive and convective, and can be enhanced by the large temperature difference between the cryogenic fluid and the initially ambient temperature of the tool material. Thus, the process utilizes the impingement of a fast-expanding cryogenic jet (or jets) on the surface of the forming tool while avoiding or minimizing the contact of the cryogenic fluid with the workpiece or work material. In this process, the forming tool retains the desired hardness and strength while the work material is thermally unconstrained, i.e., is free to soften under the tool pressure and plastically flow or shear during the forming process.
[0052] The temperature of the tool surface may be at or below room temperature, and the allowable lower temperature limit depends on the properties of the tool material. For carbon tool steels and ferritic-martensitic tool steels, the lower temperature limit should be in the range of about minus 30° C. to about minus 50° C., since temperatures below this range would fall under the ductile-brittle transition point of those steels and result in undesired tool embrittlement. In the case of tungsten and/or molybdenum carbide and other hard tool materials, designed to operate within their brittle regimes, the lower temperature limit can be equal to the cryogenic jet temperature.
[0053] The cryogenic fluid used for cooling the tool surface can comprise a gas-phase, liquid-phase, solid-phase, or multi-phase stream. The cryogenic fluid may be nitrogen, argon, carbon dioxide, or any mixture of these. The fluid may be liquid, vapor, or multi-phase and may contain solid particles. An advantageous cryogenic fluid is a jet of saturated boiling liquid nitrogen, which produces a large thermal gradient at the tool surface and promotes very rapid cooling of the surface. The process used in the embodiments of the present invention is made possible by an unexpected behavior of such a jet. When the jet (which consists of many very fine liquid droplets in a cryo-vapor envelope) impinges on a tool surface, the jet boils off or evaporates at the point of impact and does not splash away to cool adjacent surfaces and components. Such a jet can be conveniently used for selective cooling of tool surface without undesired cooling of the work material. This observed jet behavior contrasts with that of water or oil-based conventional coolant jets, which tend to splash off and impinge on surrounding surfaces.
[0054] Certain work materials (e.g., aluminum) and certain operations (e.g., drawing), as well as aggressive forming conditions, may require the use of minute quantities of lubricating material at the interface between the tool and the work material to prevent frictional welding. In these cases, the cryogenic fluid jet and the lubricating material may be applied simultaneously. The lubricating material may be a microscopic quantity of vegetable oil mist co-sprayed with the cryogen. During experimental tests, co-spraying oil with cryogen did not cause a fog of oil, possibly due to the fact that the cryogen cooled and caused the oil droplets to become tacky. This enabled the oil droplets to stick to the target surface better than in the absence of cryogenic cooling, and oily fogs were not formed as are observed in the conventional art of ambient lubricant spraying.
[0055] The lubricating material may be a suspension of micron- and submicron-sized powder suspended in the cryogenic fluid jet, whether the jet is liquid or gaseous. Such fine powders act as a boundary lubricating, dry medium, and can be combined with the cryogenic jet cooling. Finally, the micro-lubricating medium may be a microscopic quantity of solid material that is smeared over the surface of the tool and/or work material by rubbing. The solid medium may be borax, boric acid, hexagonal boron nitride, or similar solids known reduce friction coefficients and prevent interfacial reactions.
[0056] In general, boron-based lubricants may be used during forming of non-ferrous metal surfaces, e.g., aluminum surfaces, and in forming operations which should minimize carbon contamination, e.g., forming surfaces of tungsten or molybdenum emission electrodes operating in vacuum or in gaseous atmospheres. LuBoron LCC and BAGL are examples of liquid-phase, orthoboric acid-based lubricants available from Advanced Lubrication Technology, Inc.
[0057] The lubricant should be applied in a very small or microscopic quantity such that the lubricant layer cannot be easily detected by visual examination of the covered surface with naked eye or magnifying glass. The presence of such a microlubricating layer may be detected by determining the surface energy of the lubricant-covered surface by any conventional test method, e.g., by spreading droplets of inks of known surface energy. For the embodiments of the present invention, the surface of a micro-lubricated work material or workpiece may have a surface energy of less than about 38 milliNewtons per meter (38 mN/m), and may be considered lubricant-free if the surface energy is above about 46 mN/m. In the case of oil-based lubricants, the amount of microlubricant required to reduce the energy from 46 to 38 mN/m can be less than about 100 milligrams per square foot of work and/or tool surface.
[0058] Embodiments of the present invention may be applied to exemplary shaping processes such as, for example, the use of rotating tools for plastic deformation of a workpiece in contour and profile roll forming, power spinning, roll forging, orbital forging, and shoe-type pinch forming. The embodiments also may be applied in the exemplary use of (a) shearing and parting tools for separating workpieces in alligator shearing, guillotine shearing, punch parting, rotary shearing, shearing in a shearing line, and slitting; (b) drawing tools in punch drawing, wire and rod drawing, tube drawing, and moving mandrel drawing; and (c) stroke forming tools in die and punch press bending, moving insert straightening, hammer forming, and die forging. Other shaping processes not listed here also may be amenable to application of the embodiments of the present invention.
[0059] An embodiment of the invention is illustrated in FIG. 2A for contour and profile roll forming. In this forming process, a flat feed workpiece (not shown) is fed between upper contour roller 101 and counter-rotating lower contour roller 102 to produce channeled formed product 103 . Cryogenic fluid 104 is fed to spray feed line and nozzle 105 to form jet 106 that impinges on upper contour roller 101 , thereby cooling the roller. Additionally or alternatively, cryogenic fluid 107 is fed to spray feed line and nozzle 108 to form jet 109 that impinges on lower contour roller 102 , thereby cooling the roller. Essentially all of the cryogenic fluid, i.e., at least 90% of cryogenic fluids 104 and 107 and jets 106 and 109 , may impinge on the rollers. The use of the cryogenic fluid may cool each roller to a geometric average temperature that is less than the geometric average temperature of channeled formed product 103 following termination of contact of rollers 101 and 102 with formed product 103 .
[0060] Another embodiment of the invention is illustrated in FIGS. 2B and 2C for power spinning. In this forming process, initial blank or workpiece 201 ( FIG. 2B ) is placed on top of mandrel 202 that is rotated by turntable 203 . Roller 205 contacts the rotating workpiece and is forced downward on the workpiece by vertical positioner 206 , thereby changing the shape of the workpiece to final shaped product 207 shown in FIG. 2C 2 B. During shaping, cryogenic fluid 208 is fed to spray feed line and nozzle 209 to form jet 210 that impinges on roller 205 , thereby cooling the roller. Essentially all of the cryogenic fluid, i.e., at least 90% of cryogenic fluid 208 and jet 210 , may impinge on the roller. The use of the cryogenic fluid may cool the roller to a geometric average temperature that is less than the geometric average temperature of final shaped product 207 .
[0061] Another embodiment of the invention is illustrated in FIG. 3 for roll forging. In this forming process, a flat feed workpiece (not shown) is fed on table 301 between upper roll die 302 and counter-rotating lower roll die 303 to produce a roll-forged product (not shown). Cryogenic fluid 304 is fed to spray feed line and nozzle 305 to form jet 306 that impinges on upper roll die 302 , thereby cooling the roll die. Additionally or alternatively, cryogenic fluid 307 is fed to spray feed line and nozzle 308 to form jet 309 that impinges on lower roll die 303 , thereby cooling the roll die. Essentially all of the cryogenic fluid, i.e., at least 90% of cryogenic fluids 304 and 307 and jets 306 and 309 , may impinge on the rollers. The use of the cryogenic fluid may cool each roller to a geometric average temperature that is less than the geometric average temperature of the roll-forged product.
[0062] Another embodiment of the invention is illustrated in FIG. 4 for orbital forging. In this forming process, a flat feed workpiece (not shown) is initially placed on lower die 401 . Upper die 402 is lowered and pressed against the feed workpiece as the two dies rotate in the same direction. As upper die 402 (which is convex) is rotated against lower die 401 (which is concave), the feed workpiece is formed to produce orbitally-forged product piece 403 . Cryogenic fluid 404 is fed to spray feed line and nozzle 405 to form jet 406 that impinges on upper die 402 , thereby cooling the die. Additionally or alternatively, cryogenic fluid 407 is fed to spray feed line and nozzle 408 to form jet 409 that impinges on lower die 401 , thereby cooling the roll die. Essentially all of the cryogenic fluid, i.e., at least 90% of cryogenic fluids 404 and 407 and jets 406 and 409 , may impinge on the dies. The use of the cryogenic fluid may cool each die to a geometric average temperature that is less than the geometric average temperature of orbitally-forged product 403 .
[0063] Another embodiment of the invention is illustrated in FIG. 5 for shoe-type pinch rolling. In this-forming process, workpiece 501 is placed on top of shoe 502 and is contacted by rollers 503 , 504 , and 505 . The rollers and shoe are located to roll bend the workpiece as shown. During rolling, cryogenic fluid 506 is fed to spray feed line and nozzle 507 to form jet 508 that impinges on shoe 502 , thereby cooling the shoe. Essentially all of the cryogenic fluid, i.e., at least 90% of cryogenic fluid 506 and jet 507 , may impinge on the shoe. The use of the cryogenic fluid may cool the shoe to a geometric average temperature that is less than the geometric average temperature of final roll-bent workpiece 509 .
[0064] Another embodiment of the invention is illustrated in FIG. 6 for alligator shearing. In this forming process, a feed workpiece (not shown) is placed between upper blade 601 and lower blade 602 . Upper blade moves downward against the workpiece, forcing it against lower blade 602 , thereby causing shearing forces that cut and separate a product piece (not shown) from the feed workpiece. During cutting, cryogenic fluid 603 is fed to spray feed line and nozzle 604 to form jet 605 that impinges on lower blade 602 , thereby cooling the blade. Alternatively or additionally, cryogenic fluid 606 is fed to spray feed line and nozzle 607 to form jet 608 that impinges on upper blade 601 , thereby cooling the blade. Essentially all of the cryogenic fluid, i.e., at least 90% of cryogenic fluids 603 and 606 and jets 605 and 608 , may impinge on the blades. The use of the cryogenic fluid may cool each blade to a geometric average temperature that is less than the geometric average temperature of the product piece.
[0065] Another embodiment of the invention is illustrated in FIG. 7 for guillotine shearing. In this forming process, a feed workpiece (not shown) is placed between upper blade 701 and lower blade 702 . Upper blade moves downward against the workpiece, forcing it against lower blade 702 , thereby causing shearing forces that cut and separate a product piece (not shown) from the feed workpiece. During cutting, cryogenic fluid 703 is fed to spray feed line and nozzle 704 to form jet 705 that impinges on lower blade 702 , thereby cooling the blade. Additionally or alternatively, cryogenic fluid is fed to another spray feed line and nozzle (not seen behind upper blade 701 and bladeholder 706 ) to form a jet that impinges on the rear side of upper blade 701 , thereby cooling the blade. Essentially all of the cryogenic fluid, i.e., at least 90% of cryogenic fluid 703 and jet 705 , as well as the fluid and jet cooling upper blade 701 , may impinge on the blades. The use of the cryogenic fluid may cool each blade to a geometric average temperature that is less than the geometric average temperature of the product piece.
[0066] Another embodiment of the invention is illustrated in FIG. 8 for punch parting. In this forming process, feed workpiece 801 is placed on a lower fixed support (not shown) having sufficient clearance to allow full vertical movement of punch 802 . The punch moves downward against the workpiece, forcing it against the lower fixed support, thereby causing shearing forces that cut and separate waste piece 803 from feed workpiece 801 , thereby forming product pieces 804 a and 804 b. During punching, cryogenic fluid 805 is fed to spray feed line and nozzle 806 to form jet 807 that impinges on punch 802 , thereby cooling the punch. Additionally or alternatively, cryogenic fluid may be fed to another spray feed line and nozzle (not shown behind punch 802 ) to form a jet that impinges on the rear side of punch, thereby cooling the punch. Essentially all of the cryogenic fluid, i.e., at least 90% of cryogenic fluid 805 and jet 806 , as well as the fluid and jet cooling the back of punch 802 , may impinge on the punch. The use of the cryogenic fluid may cool the punch to a geometric average temperature that is less than the geometric average temperature of product piece.
[0067] Another embodiment of the invention is illustrated in FIG. 9 for rotary shearing. In this forming process, feed workpiece 901 is placed between upper rotary cutter 902 and lower rotary cutter 903 . Upper rotary cutter 902 moves downward against the workpiece, forcing it against lower rotary cutter 903 , thereby causing shearing forces that cut and separate a product piece (not shown) from feed workpiece 901 . During cutting, cryogenic fluid 904 is fed to spray feed line and nozzle 905 to form jet 906 that impinges on upper rotary cutter 902 , thereby cooling the cutter. Additionally or alternatively, cryogenic fluid is fed to spray feed line 907 and nozzle 908 to form jet 909 that impinges on lower rotary cutter 903 , thereby cooling the cutter. Essentially all of the cryogenic fluid, i.e., at least 90% of cryogenic fluids 904 and 907 and jets 906 and 909 , may impinge on the rotary cutters. The use of the cryogenic fluid may cool each cutter to a geometric average temperature that is less than the geometric average temperature of the product piece.
[0068] Another embodiment of the invention is illustrated in FIG. 10 for shearing in a shearing line. In this forming process, coilstock 1001 is fed between straightening rolls 1003 and over hump table 1004 . Stationary shear 1005 cuts the straightened stock into product sheets that pass over gage table 1006 having a retractable stop and stacker that stacks the cut sheets 1007 as they are delivered from the gage table. Cryogenic fluid 1008 is fed to spray feed line and nozzle 1009 to form jet 1010 that impinges on the blade of stationary shear 1005 , thereby cooling the blade. Essentially all of the cryogenic fluid, i.e., at least 90% of cryogenic fluid 1008 and jet 1010 , may impinge on the blade. The use of the cryogenic fluid may cool the blade to a geometric average temperature that is less than the geometric average temperature of each product sheet that passes over gage table 1006 .
[0069] Another embodiment of the invention is illustrated in FIG. 11 for slitting in a slitting line. In this forming process, slitting is accomplished by feeding stock from uncoiler 1101 and passing uncoiled strip 1102 strip to slitter 1103 , where it passes between slightly overlapping circular blades 1104 mounted on rotating arbors. Slit product strips 1105 are taken up by recoiler 1106 for simultaneous coiling of all slit strips. Cryogenic fluid 1107 is fed to spray feed line and nozzle 1108 to form jet 1109 that impinges on the circular blades 1104 , thereby cooling the blades. Essentially all of the cryogenic fluid, i.e., at least 90% of cryogenic fluid 1107 and jet 1109 , may impinge on the blades. The use of the cryogenic fluid may cool the blades to a geometric average temperature that is less than the geometric average temperature of each product strip 1105 .
[0070] Another embodiment of the invention is illustrated in FIG. 12 for wire and rod drawing. In this forming process, feed workpiece 1201 having a given diameter is fed through die 1202 to deform the feed workpiece and reduce the diameter to yield drawn product 1203 having a reduced diameter. Cryogenic fluid 1204 is fed to spray feed line and nozzle 1205 to form jet 1206 that impinges on die 1202 , thereby cooling the die. Additional cryogenic fluid may be applied (not shown) at other radial locations on the die. Essentially all of the cryogenic fluid, i.e., at least 90% of cryogenic fluid 1204 and jet 1206 (and/or cryogenic fluid applied at other radial locations on the die) may impinge on the die. The use of the cryogenic fluid may cool die 1202 to a geometric average temperature that is less than the geometric average temperature of drawn product 1203 .
[0071] Another embodiment of the invention is illustrated in FIG. 13 for tube drawing or sinking. In this forming process, feed tubing workpiece 1301 having a given outer diameter is fed through die 1303 held in frame 1303 to deform the feed workpiece and reduce the diameter to yield drawn tube product 1304 having a reduced diameter. Cryogenic fluid 1305 is fed to spray feed line and nozzle 1306 to form jet 1307 that impinges on die 1302 , thereby cooling the die. Cryogenic fluid may be applied to any location on the die, including more than one location. In addition to or as an alternative to applying cryogenic fluid to the die, cryogenic fluid may be applied to any location on frame 1303 as illustrated by cryogenic fluid 1308 , feed line and nozzle 1309 , and jet 1310 . Essentially all of the cryogenic fluid, i.e., at least 90% of cryogenic fluid 1305 and jet 1307 (and/or cryogenic fluid applied at other radial locations on the die and at locations on the frame) may impinge on the die and frame. The use of the cryogenic fluid may cool each of die 1302 and frame 1303 to a geometric average temperature that is less than the geometric average temperature of drawn product 1304 .
[0072] Another embodiment of the invention is illustrated in FIG. 14 for tube drawing with a moving mandrel. In this forming process, workpiece 1401 having a given outer diameter is pushed through die 1402 by moving mandrel 1403 to deform the feed workpiece and reduce the diameter to yield a final drawn product piece (not shown) having a reduced diameter. Cryogenic fluid 1404 is fed to exemplary spray feed line and nozzle 1405 to form jet 1406 that impinges on die 1402 , thereby cooling the die. Cryogenic fluid may be applied at any location (including more than one location) on the die. In addition to or as an alternative to applying cryogenic fluid to the die, cryogenic fluid may be applied to any location on mandrel 1403 as illustrated by cryogenic fluid 1407 , feed line and nozzle 1408 , and jet 1409 . This application may be done while the mandrel is at any position as it moves axially. Essentially all of the cryogenic fluid, i.e., at least 90% of cryogenic fluid 1404 and jet 1406 (and/or cryogenic fluid applied at other radial locations on the die and at locations on the frame) may impinge on the die and frame. The use of the cryogenic fluid may cool each of die 1302 and frame 1303 to a respective geometric average temperature that is less than the geometric average temperature of the final drawn product.
[0073] Another embodiment of the invention is illustrated in FIG. 15 for punch drawing with a moving punch. In this forming process, die 1501 is provided with receiving nest or locator 1502 to hold a blank feed workpiece (not shown). This blank workpiece is deformed by downward axial movement of punch 1503 through the die as shown to form product piece 1504 . Cryogenic fluid 1505 is fed to spray feed line and nozzle 1506 to form jet 1507 that impinges on die 1501 , thereby cooling the die. Cryogenic fluid may be applied to any location, including more than one location, on the die. In addition to or as an alternative to applying cryogenic fluid to the die, cryogenic fluid may be applied to any location on punch 1503 as illustrated by cryogenic fluid 1508 , feed line and nozzle 1509 , and jet 1510 . Essentially all of the cryogenic fluid, i.e., at least 90% of cryogenic fluid 1505 and jet 1507 (and/or cryogenic fluid applied at other locations on the die and at locations on the punch) may impinge on the die and punch. The use of the cryogenic fluid may cool each of die 1501 and punch 1503 to a respective geometric average temperature that is less than the geometric average temperature of product piece 1504 .
[0074] Another embodiment of the invention is illustrated in FIG. 16 for moving insert straightening. Workpiece 1601 is positioned between two rows of movable inserts 1602 , and 1603 situated in tool base 1604 . The workpiece is subjected to a series of reciprocal strokes by the movable inserts that overbend the workpiece by a preset amount. The amplitude of the movement is progressively reduced during the cycle until it approaches a straight line, at which point a final straight workpiece is produced. The degree of bending movement and the number of bending cycles are adjustable, and varying insert spacing is available to accommodate a wide range of soft or heat-treated components. Some or all of movable inserts 1602 and 1603 may be cooled with a cryogenic fluid. To illustrate this, there is shown cryogenic fluid 1605 fed to spray feed line and nozzle 1606 to form jet 1607 that impinges on one of inserts 1602 , thereby cooling the insert. For further illustration, there is shown cryogenic fluid 1608 fed to spray feed line and nozzle 1609 to form jet 1610 that impinges on one of inserts 1603 , thereby cooling the insert. Cryogenic fluid may be applied to any location on any insert. Essentially all of the cryogenic fluid, i.e., at least 90% of cryogenic fluids 1605 and 1608 and jets 1607 and 1610 (and cryogenic fluid applied at other locations on the inserts) may impinge on the inserts. The use of the cryogenic fluid may cool each of inserts to a respective geometric average temperature that is less than the geometric average temperature of the final straight workpiece.
[0075] Additional embodiments of the invention are illustrated in FIGS. 17A, 17B , 17 C, and 17 D for press-brake forming. In this process, punches 1701 , 1702 , 1703 , and 1704 , respectively, are forced against dies 1705 , 1706 , 1707 , and 1708 , respectively, to produce formed workpieces 1709 , 1710 , 1711 , and 1712 , respectively. Cryogenic fluid may be applied to either or both of the punch and the die in each of FIGS. 17A, 17B , 17 C, and 17 D. FIG. 17A illustrates the application of cryogenic fluid 1713 via spray feed line and nozzle 1714 to form jet 1715 that impinges on punch 1701 , thereby cooling the punch. Also illustrated is the application of cryogenic fluid 1716 via spray feed line and nozzle 1717 to form jet 1718 that impinges on die 1705 , thereby cooling the die.
[0076] FIG. 17B illustrates the application of cryogenic fluid 1719 via spray feed line and nozzle 1720 to form jet 1721 that impinges on punch 1702 , thereby cooling the punch. Also illustrated is the application of cryogenic fluid 1722 via spray feed line and nozzle 1723 to form jet 1724 that impinges on die 1706 , thereby cooling the die.
[0077] FIG. 17C illustrates the application of cryogenic fluid 1725 via spray feed line and nozzle 1726 to form jet 1727 that impinges on punch 1703 , thereby cooling the punch. Also illustrated is the application of cryogenic fluid 1728 via spray feed line and nozzle 1729 to form jet 1730 that impinges on die 1707 , thereby cooling the die.
[0078] FIG. 17D illustrates the application of cryogenic fluid 1731 via spray feed line and nozzle 1732 to form jet 1733 that impinges on punch 1704 , thereby cooling the punch. Also illustrated is the application of cryogenic fluid 1734 via spray feed line and nozzle 1735 to form jet 1736 that impinges on die 1708 , thereby cooling the die.
[0079] Cryogenic fluid may be applied to any location on any of the punches and dies in FIGS. 17A, 17B , 17 C, and 17 D. Essentially all of the cryogenic fluid, i.e., at least 90% of each cryogenic fluid and corresponding jet in FIGS. 17A, 17B , 17 C, and 17 D may impinge on the respective punch or die. The use of the cryogenic fluid may cool each punch and die to a respective geometric average temperature that is less than the geometric average temperature of the final formed workpiece.
[0080] Another embodiment of the invention is illustrated in FIG. 18 for drop hammer forming. In this process, a workpiece (not shown) is placed between punch 1801 and die 1802 , and the punch is lowered to press against the workpiece and the die one or more times, thereby forming the workpiece to yield a final formed article. This power drop hammer may be powered by compressed air in cylinder 1803 , which moves piston 1804 , connecting rod 1805 , and ram 1806 to lower punch 1801 . Cryogenic fluid may be applied to either or both of the punch and the die. FIG. 18 illustrates the application of cryogenic fluid 1807 via spray feed line and nozzle 1808 to form jet 1809 that impinges on punch 1801 , thereby cooling the punch. Also illustrated is the application of cryogenic fluid 1810 via spray feed line and nozzle 1811 to form jet 1812 that impinges on die 1802 , thereby cooling the die. Essentially all of the cryogenic fluid, i.e., at least 90% of each cryogenic fluid and corresponding jet in FIG. 18 may impinge on the respective punch or die. The use of the cryogenic fluid may cool the punch and die to a respective geometric average temperature that is less than the geometric average temperature of the final formed article.
[0081] Another embodiment of the invention is illustrated in FIG. 19 for open die forging. In this forming process, a workpiece (not shown) is placed between top die 1901 and bottom die 1902 , and the top die is lowered to press against the workpiece and the bottom die one or more times, thereby forming the workpiece to yield a final formed article. This open die forge may be powered by steam in cylinder 1903 , which moves piston rod 1904 and ram 1905 to move top die 1901 against bottom die 1902 . Cryogenic fluid may be applied to either or both of the punch and the die. FIG. 19 illustrates the application of cryogenic fluid 1906 via spray feed line and nozzle 1907 to form jet 1908 that impinges on top die 1901 , thereby cooling the top die. Also illustrated is the application of cryogenic fluid 1909 via spray feed line and nozzle 1910 to form jet 1911 that impinges on lower die 1902 , thereby cooling the lower die. Essentially all of the cryogenic fluid, i.e., at least 90% of each cryogenic fluid and corresponding jet in FIG. 19 may impinge on the respective dies. The use of the cryogenic fluid may cool each die to a respective geometric average temperature that is less than the geometric average temperature of the final formed article.
[0082] In the illustrations described above with reference to FIGS. 1-19 , the workpieces typically may be made of metal or metal alloys. Alternatively, any of the processes may be used with workpieces made of non-metallic materials capable of being plastically deformed, sheared, cut, or otherwise formed without the removal of material as defined above.
[0083] The cryogenic fluid may be applied to the desired surface by spraying, jetting, or otherwise directing the fluid to contact and cool the surface of a tool. Any method known in the art may be used, and exemplary methods are described in U.S. Pat. Nos. 6,513,336 B2, 6,564,682 B1, and 6,675,622 B2 and in U.S. Patent Publications 20040237542 A1, 20050211029 A1, 20050016337 A1, 20050011201 A1, and 20040154443 A1, all of which are fully incorporated herein by reference.
[0084] Any type of nozzle or open-ended tubing discharging a pressurized cryogenic liquid or multi-phase cryogenic fluid may be used. The thermodynamic condition of the discharged stream (i.e., the stream decompressed at the nozzle exit) typically is such that the discharge results in a partial vaporization of the liquid phase and at least partial disintegration of this liquid into fine, rapidly-moving cryogenic liquid droplets. Typical flow rates of the discharged cryogenic fluid may range from 0.25 to 1.0 lb per min per nozzle at typical supply pressures in the range of 20 to 220 psig. The discharged liquid and vapor typically are saturated at equilibrium at the discharge temperature and pressure; alternatively, the liquid may be slightly subcooled, typically by a few ° C. to about 20° C. below the saturation temperature at the given pressure.
[0085] Any appropriate liquid lubricant may be used; the liquid lubricant may be essentially water-free, or alternatively may contain water. A liquid lubricant is liquid at temperatures in the range of about minus 40° C. to about plus 40° C. Oil-water emulsions may be used as lubricants in embodiments of the invention. Any commercially-available cutting oil or cutting fluid may be used to provide the lubricant. Exemplary liquid lubricants for use in embodiments of the present invention are given above.
[0086] Solid lubricants (for example, paraffin wax) or semi-solid lubricants (for example, pumpable greases or other flowable materials) may be used instead of (or in addition to) liquid lubricants. A solid lubricant typically is solid at ambient temperatures or below, e.g., below about 40° C. Some solid lubricants may remain solid at temperatures above 40° C. Any appropriate solid or semi-solid lubricant may be used; the lubricant may be essentially water-free, or alternatively may contain water. Solid or semi-solid lubricants typically are applied by pressing, rubbing, smearing, or otherwise directing the solid lubricant to contact the surface of a tool or workpiece and to penetrate and/or fill the microscopic regions formed by the surface asperities. The area of the surface to which the solid or semi-solid lubricant is applied may be cooled in the same manner as described above for liquid lubricants. In most embodiments, the solid or semi-solid lubricant is applied before the area is cooled. | Method of forming a workpiece comprising (a) providing a tool and a workpiece, wherein the workpiece has an initial shape; (b) placing the workpiece and the tool in contact, applying force to the tool and/or the workpiece, and moving the tool and/or the workpiece to effect a change in the initial shape of the workpiece by forming; and (c) providing a jet of cryogenic fluid and impinging essentially all of the jet of cryogenic fluid on a surface of the tool. | 1 |
FIELD OF THE INVENTION
The present invention relates, in general, to racemic or enantiomerically enriched benzoyl piperidine compounds and pharmaceutically useful salts thereof, a pharmaceutical composition comprising an effective amount of racemic or enantiomerically enriched benzoyl piperidine compounds to treat central nervous system diseases and a method of treating central nervous system diseases in a mammal. More particularly, the present invention relates to racemic or enantiomerically enriched O-carbamoyl, alkoxy, azole or carbonate benzoyl piperidine compounds and pharmaceutically useful salts thereof, useful to treat the diseases of the central nervous system such as psychosis and cognition disorder. Also, the present invention is concerned with a process for preparing the same.
BACKGROUND OF THE INVENTION
Many reports have disclosed that benzoyl piperidine compounds are effectively used for controlling various central nervous system (CNS) disorders, especially as antipsychotic and analgesics.
1-[n-(2-alkylthio-10H-phenothiazin-10-yl)alkyl]-4-benzoylpiperidines were disclosed in U.S. Pat. No. 4,812,456 and 6,7-dihydro-3-phenyl-1,2-benzisoxazol-4(5H)-ones and -ols were disclosed in U.S. Pat. No. 5,114,936. These compounds are found to be very effective as therapeutical medicines for managing CNS disease, such as antipsychotic and analgesics.
Active research and development efforts have been continued to be directed to the application of benzoyl piperidine compounds for the treatment of CNS disorders.
SUMMARY OF THE INVENTION
A principal object of the present invention is to provide racemic or enantiomerically enriched benzoyl piperidine compounds, represented by the following structural formula (I) and pharmaceutically acceptable salts thereof:
wherein
n is 0; and
A is selected from the group consisting of phenyl which may be substituted with one or more identical or different substituents selected from the group consisting of hydrogen, halogen, straight or branched chain alkyl of from 1 to 4 carbon atoms, straight or branched chain alkoxy of from 1 to 3 carbon atoms, nitro, cyano, trifluoromethyl, trifluoromethoxy, methanesulfonyl and phenyl; thienyl; naphthyl; pyridyl; and quinolyl; or
n is an integer from 1 to 2; and
A is selected from the group consisting of phenyl or phenoxy which may be substituted with one or more identical or different substituents selected from the group consisting of hydrogen, halogen, straight or branched chain alkyl of from 1 to 4 carbon atoms, straight or branched chain alkoxy of from 1 to 3 carbon atoms, nitro, cyano, trifluoromethyl, trifluoromethoxy, methanesulfonyl and phenyl; thienyl; naphthyl; pyridyl; and quinolyl;
X is selected from the group consisting of O-carbamoyl, straight or branched chain alkoxy of from 1 to 4 carbon atoms, imidazole, triazole, tetrazole and carbonate; and
Y is selected from the group consisting of hydrogen, halogen, straight or branched chain alkyl of from 1 to 4 carbon atoms and straight or branched chain alkoxy of from 1 to 3 carbon atoms.
More specifically, the present benzoyl piperidine compounds represented by the above formula (I) comprises racemic or enantiomerically enriched compounds represented by the following structural formula (V), (VIII), (XIV), and (XVI):
wherein
n is 0 ; and
A is selected from the group consisting of phenyl which may be substituted with one or more identical or different substituents selected from the group consisting of hydrogen, halogen, straight or branched chain alkyl of from 1 to 4 carbon atoms, straight or branched chain alkoxy of from 1 to 3 carbon atoms, nitro and trifluoromethyl; and naphthyl; or
n is an integer from 1 to 2; and
A is selected from the group consisting of phenyl or phenoxy which may be substituted with one or more identical or different substituents selected from the group consisting of hydrogen, halogen, straight or branched chain alkyl of from 1 to 4 carbon atoms, straight or branched chain alkoxy of from 1 to 3 carbon atoms, nitro and trifluoromethyl; and naphthyl;
Y is selected from the group consisting of hydrogen, halogen, straight or branched chain alkyl of from 1 to 4 carbon atoms and straight or branched chain alkoxy of from 1 to 3 carbon atoms; and
R1 and R2 may be the same with or different from each other and are independently selected from the group consisting of hydrogen, methoxy, benzyl and 5 to 7-membered aliphatic cyclic compounds:
wherein
n is 0; and
A is selected from the group consisting of phenyl which may be substituted with one or more identical or different substituents selected from the group consisting of hydrogen, halogen, straight or branched chain alkyl of from 1 to 4 carbon atoms, straight or branched chain alkoxy of from 1 to 3 carbon atoms, nitro, cyano, trifluoromethyl, trifluoromethoxy, methanesulfonyl, phenyl; thienyl; naphthyl; pyridyl; and quinolyl; or
n is an integer from 1 to 2; and
A is selected from the group consisting of phenyl or phenoxy which may be substituted with one or more identical or different substituents selected from the group consisting of hydrogen, halogen, straight or branched chain alkyl of from 1 to 4 carbon atoms, straight or branched chain alkoxy of from 1 to 3 carbon atoms, nitro, cyano, trifluoromethyl, trifluoromethoxy, methanesulfonyl, phenyl; thienyl; naphthyl; pyridyl; and quinolyl;
Y is selected from the group consisting of hydrogen, halogen, straight or branched chain alkyl of from 1 to 4 carbon atoms, and straight or branched chain alkoxy of from 1 to 3 carbon atoms; and
R3 is selected from the group consisting of straight or branched chain alkyl of from 1 to 4 carbon atoms, aliphatic cyclic compound of from 5 to 7 carbon atoms, and benzyl:
wherein
n is an integer from 0 to 2;
A is selected from the group consisting of phenyl which may be substituted with one or more identical or different substituents selected from the group consisting of hydrogen, halogen, straight or branched chain alkyl of from 1 to 4 carbon atoms, straight or branched chain alkoxy of from 1 to 3 carbon atoms, nitro and trifluoromethyl; and naphthyl;
Y is selected from the group consisting of hydrogen, halogen, straight or branched chain alkyl of from 1 to 4 carbon atoms, and straight or branched chain alkoxy of from 1 to 3 carbon atoms; and
X is imidazole, triazole, or tetrazole moiety having the following formula (XII):
wherein
n is 0 ; and
A is selected from the group consisting of phenyl which may be substituted with one or more identical or different substituents selected from the group consisting of hydrogen, halogen, straight or branched chain alkyl of from 1 to 4 carbon atoms, straight or branched chain alkoxy of from 1 to 3 carbon atoms, nitro, cyano and trifluoromethyl; or
n is an integer from 1 to 2; and
A is selected from the group consisting of phenyl or phenoxy which may be substituted with one or more identical or different substituents selected from the group consisting of hydrogen, halogen, straight or branched chain alkyl of from 1 to 4 carbon atoms, straight or branched chain alkoxy of from 1 to 3 carbon atoms, nitro, cyano and trifluoromethyl;
Y is selected from the group consisting of hydrogen, halogen, straight or branched chain alkyl of from 1 to 4 carbon atoms, and straight or branched chain alkoxy of from 1 to 3 carbon atoms; and
R4 is selected from the group consisting of straight or branched chain alkyl of from 1 to 3 carbon atoms, phenyl and benzyl.
It is another object of the present invention to provide a pharmaceutical composition comprising an effective amount of racemic or enantiomerically enriched benzoyl piperidine compounds represented by the above structural formula (I), in particular, the compounds represented by the above structural formula (V), (VIII), (XIV) and (XVI), for treating disorders of central nervous system such as psychosis and cognition disorder.
It is still another object of the present invention to provide a method of treating disorders of central nervous system such as psychosis and cognition disorder in a mammal by administering an effective amount of racemic or enantiomerically enriched benzoyl piperidine compounds represented by the above structural formula (I), in particular, the compounds represented by the above structural formula (V), (VIII), (XIV) and (XVI) and a pharmaceutical acceptable carrier to a mammal in need of psychosis and cognition therapy.
DETAILED DESCRIPTION OF THE INVENTION
In accordance with the present invention, the compound represented by the structural formula I and pharmaceutical acceptable salts thereof can be prepared by the following steps starting from amino alcohol compounds represented by the following general structural formula (II):
wherein
n is 0; and
A is selected from the group consisting of phenyl which may be substituted with one or more identical or different substituents selected from the group consisting of hydrogen, halogen, straight or branched chain alkyl of from 1 to 4 carbon atoms, straight or branched chain alkoxy of from 1 to 3 carbon atoms, nitro, cyano, trifluoromethyl, trifluoromethoxy, methanesulfonyl and phenyl; thienyl; naphthyl; pyridyl; and quinolyl; or
n is an integer from 1 to 2; and
A is selected from the group consisting of phenyl or phenoxy which may be substituted with one or more identical or different substituents selected from the group consisting of hydrogen, halogen, straight or branched chain alkyl of from 1 to 4 carbon atoms, straight or branched chain alkoxy of from 1 to 3 carbon atoms, nitro, cyano, trifluoromethyl, trifluoromethoxy, methanesulfonyl and phenyl; thienyl; naphthyl; pyridyl; and quinolyl; and
Y is selected from the group consisting of hydrogen, halogen, straight or branched chain alkyl of from 1 to 4 carbon atoms and straight or branched chain alkoxy of from 1 to 3 carbon atoms.
The method for preparing the amino alcohol compounds represented by the general structural formula (II) will be described below in detail.
Reacting epoxide represented by the following structural formula (III);
wherein n and A are the same as defined above;
with benzoyl piperidine represented by the following structural formula (IV):
wherein Y is the same as defined above;
to synthesize amino alcohol compounds represented by the structural formula (II).
It should be noted that the stereochemistry of the product (I, II, V, VIII, XIV and XVI) depends solely on that of the starting material (III); a starting material (III) with an (S)-enantiomer yields only a product with (S)-enantiomer and a starting material (III) with an (R)-enantiomer yields only a product with (R)-enantiomer.
The method for preparing the O-carbamoyl benzoyl piperidine compounds represented by the following general structural formula (V) will be described below in detail.
wherein
n is 0; and
A is selected from the group consisting of phenyl which may be substituted with one or more identical or different substituents selected from the group consisting of hydrogen, halogen, straight or branched chain alkyl of from 1 to 4 carbon atoms, straight or branched chain alkoxy of from 1 to 3 carbon atoms, nitro and trifluoromethyl; and naphthyl; or
n is an integer from 1 to 2; and
A is selected from the group consisting of phenyl or phenoxy which may be substituted with one or more identical or different substituents selected from the group consisting of hydrogen, halogen, straight or branched chain alkyl of from 1 to 4 carbon atoms, straight or branched chain alkoxy of from 1 to 3 carbon atoms, nitro and trifluoromethyl; and naphthyl;
Y is selected from the group consisting of hydrogen, halogen, straight or branched chain alkyl of from 1 to 4 carbon atoms and straight or branched chain alkoxy of from 1 to 3 carbon atoms; and
R1 and R2 may be the same with or different from each other and are independently selected from the group consisting of hydrogen, methoxy, benzyl and 5 to 7-membered aliphatic cyclic compounds.
The O-carbamoyl benzoyl piperidine compounds represented by the general structural formula (V) are prepared by reacting amino alcohol represented by the general structural formula (II) with 1,1′-carbonyldiimidazole and then with amine base represented by the following general structural formula (VI);
R1R2NH (VI)
wherein R1 and R2 are the same as defined above.
This procedure is summarized as set forth in Reaction Scheme I below.
Details of the reaction conditions described in Reaction Scheme I are as follows. For the conversion of the compounds (II) to the compound (V), the concentration of the starting material (II) is about 0.005 to 0.1 moles with 1,1′-carbonyldiimidazole ranging from about 2.0 to 3.0 equivalents. This reaction is preferably carried out at a temperature of 10 to 30° C. Without purification, the resulting intermediate is treated with 1 to 1,000 equivalents of amine base represented by the general formula (VI) at a temperature of 10 to 30° C. to give the compound of the general formula (V). For this carbamoylation, an ethereal solvent such as diethyl ether and tetrahydrofuran, a halogenated hydrocarbon solvent such as dichloromethane and chloroform, or the mixture thereof may be used.
In Reaction Scheme I, HX represents an acid capable of forming a pharmacologically useful salt with the basic nitrogen atom. Specific examples of the anhydrous acid used for the preparation of the compound (VII) from the compound (V) include hydrochloric acid, sulfuric acid, phosphoric acid, acetic acid, benzoic acid, citric acid, malonic acid, salicylic acid, malic acid, fumaric acid, oxalic acid, succinic acid, tartaric acid, lactic acid, gluconic acid, ascorbic acid, maleic acid, aspartic acid, benzene sulfonic acid, methane sulfonic acid, ethane sulfonic acid, hydroxymethane sulfonic acid and hydroxyethane sulfonic acid and the like. Additional acids can refer to “Pharmaceutical Salts”, J. Pharm. Sci., 1977; 66(1): 1-19. This preparation is executed in a reaction media which can be exemplified by an ethereal solvent such as tetrahydrofuran, an alcoholic solvent such as.methanol, an ester solvent such as ethyl acetate, a halogenated hydrocarbon solvent, and the mixtures thereof. An ethereal solvent is recommended as an addition solution, including ethyl ether, propyl ether, isopropyl ether, butyl ether, isobutyl ether. The concentration of the compound (V) is on the order of about 0.01 to 5 moles.
The method for preparing the alkoxy benzoyl piperidine compounds represented by the following general structural formula (VIII) will be described below in detail.
wherein
n is 0; and
A is selected from the group consisting of phenyl which may be substituted with one or more identical or different substituents selected from the group consisting of hydrogen, halogen, straight or branched chain alkyl of from. 1 to 4 carbon atoms, straight or branched chain alkoxy of from 1 to 3 carbon atoms, nitro, cyano, trifluoromethyl, trifluoromethoxy, methanesulfonyl, phenyl; thienyl; naphthyl; pyridyl; and quinolyl; or
n is an integer from 1 to 2; and
A is selected from the group consisting of phenyl or phenoxy which may be substituted with one or more identical or different substituents selected from the group consisting of hydrogen, halogen, straight or branched chain alkyl of from 1 to 4 carbon atoms, straight or branched chain alkoxy of from 1 to 3 carbon atoms, nitro, cyano, trifluoromethyl, trifluoromethoxy, methanesulfonyl, phenyl; thienyl; naphthyl; pyridyl; and quinolyl;
Y is selected from the group consisting of hydrogen, halogen, straight or branched chain alkyl of from 1 to 4 carbon atoms, and straight or branched chain alkoxy of from 1 to 3 carbon atoms; and
R3 is selected from the group consisting of straight or branched chain alkyl of from 1 to 4 carbon atoms, aliphatic cyclic compound of from 5 to 7 carbon atoms, and benzyl.
The alkoxy benzoyl piperidine compounds represented by the general structural formula (VIII) is prepared by reacting amino alcohol represented by the general structural formula (II) with methanesulfonyl chloride and triethylamine and then with alcohol represented by the following general structural formula (IX);
R3OH (IX)
wherein R3 is the same as defined above.
The alternative method for conversion of amino alcohol compounds (II) to alkoxy benzoyl piperidine compounds of the general structural formula (VIII) in which A is phenoxy is to react amino alcohol represented by the general structural formula (II) with sodium hydride and then with alkyl halide represented by the following general structural formula (X) to produce alkoxy benzoyl piperidine compounds represented by the general structural formula (VIII);
R3Z (X)
wherein Z is a halogen atom such as chloride, bromide or iodide.
The pharmaceutically acceptable salts thereof can be obtained by treating alkoxy benzoyl piperidine compounds (VIII) with an anhydrous acid in a solution without further purification.
This procedure is summarized as set forth in Reaction Scheme II below.
Details of the reaction conditions described in Reaction Scheme II are as follows. For the conversion of the compounds (II) to the compound (VIII), the concentration of the starting material (II) is about 0.005 to 0.1 moles with methanesulfonyl chloride ranging from about 3.0 to 4.0 equivalents and triethylamine ranging from about 3.0 to 4.0 equivalents. This reaction is preferably carried out at a temperature of 0 to 30° C. Without purification, the resulting intermediate is treated with 1 to 1,000 equivalents of alcohol represented by the general formula (IX) at a temperature of 30 to 90° C. to give the compound of the general formula (VIII). For this alkylation, an ethereal solvent such as diethyl ether and tetrahydrofuran, a halogenated hydrocarbon solvent such as dichloromethane and chloroform, an alcohol solvent such as methanol, ethanol and propanol, or the mixture thereof may be used.
For the alternative conversion of compound (II) to the compound (VIII) in which A is phenoxy, the concentration of the starting material (II) is about 0.01 to 0.1 moles with sodium hydride ranging from about 1.0 to 2.0 equivalents. The mixture is treated with 1.0 to 2.0 equivalents of alkyl halide represented by the general formula (X). This reaction is preferably carried out at a temperature of 0 to 20° C. For this alkylation, an ethereal solvent such as diethyl ether and tetrahydrofuran, a halogenated hydrocarbon solvent such as dichloromethane and chloroform, or the mixture thereof may be used.
In Reaction Scheme II, HX represents an acid capable of forming a pharmacologically useful salt with the basic nitrogen atom.
The method for preparing the azole benzoyl piperidine compounds represented by the general structural formula (XIV) in which X is imidazole, triazole or tetrazole moiety having the following general structural formula (XII) will be described below in detail.
wherein
n is an integer from 0 to 2;
A is selected from the group consisting of phenyl which may be substituted with one or more identical or different substituents selected from the group consisting of hydrogen, halogen, straight or branched chain alkyl of from 1 to 4 carbon atoms, straight or branched chain alkoxy of from 1 to 3 carbon atoms, nitro and trifluoromethyl; and naphthyl;
Y is selected from the group consisting of hydrogen, halogen, straight or branched chain alkyl of from 1 to 4 carbon atoms, and straight or branched chain alkoxy of from 1 to 3 carbon atoms; and
X is imidazole, triazole, or tetrazole moiety having the following formula (XII):
The azole benzoyl piperidine compounds represented by the general structural formula (XIV) in which X is imidazole, triazole or tetrazole moiety having the general structural formula (XII) is prepared by reacting amino alcohol represented by the general structural formula (II) with methanesulfonyl chloride and triethylamine and then with azole represented by the following general structural formula (XIII):
The pharmaceutically acceptable salts thereof can be obtained by treating azole benzoyl piperidine compounds with an anhydrous acid in a solution without further purification.
This procedure is summarized as set forth in Reaction Scheme III below.
Details of the reaction conditions described in Reaction Scheme III are as follows. For the conversion of the compounds (II) to the compound (XIV) in which X is imidazole, triazole or tetrazole moiety having the general structural formula (XII), the concentration of the starting material (II) is about 0.005 to 0.1 moles with methanesulfonyl chloride ranging from about 1.0 to 3.0 equivalents and triethylamine ranging from about 1.0 to 3.0 equivalents. This reaction is preferably carried out at a temperature of 0 to 30° C. Without purification, the resulting intermediate is treated with 3 to 4 equivalents of azole represented by the general formula (XIII) at a temperature of 30 to 90° C. to give the compound of the general formula (XV). For this reaction, an ethereal solvent such as diethyl ether and tetrahydrofuran, a halogenated hydrocarbon solvent such as dichloromethane and chloroform, or the mixture thereof may be used.
In Reaction Scheme III, HX represents an acid capable of forming a pharmacologically useful salt with the basic nitrogen atom.
The method for preparing the carbonate benzoyl piperidine compounds represented by the following general structural formula (XVI) will be described below in detail.
wherein
n is 0; and
A is selected from the group consisting of phenyl which may be substituted with one or more identical or different substituents selected from the group consisting of hydrogen, halogen, straight or branched chain alkyl of from 1 to 4 carbon atoms, straight or branched chain alkoxy of from 1 to 3 carbon atoms, nitro, cyano and trifluoromethyl; or
n is an integer from 1 to 2; and
A is selected from the group consisting of phenyl or phenoxy which may be substituted with one or more identical or different substituents selected from the group consisting of hydrogen, halogen, straight or branched chain alkyl of from 1 to 4 carbon atoms, straight or branched chain alkoxy of from 1 to 3 carbon atoms, nitro, cyano and trifluoromethyl;
Y is selected from the group consisting of hydrogen, halogen, straight or branched chain alkyl of from 1 to 4 carbon atoms, and straight or branched chain alkoxy of from 1 to 3 carbon atoms; and
R4 is selected from the group consisting of straight or branched chain alkyl of from 1 to 3 carbon atoms, phenyl and benzyl.
The carbonate benzoyl piperidine compounds represented by the general structural formula (XVI) is prepared by reacting amino alcohol represented by the general structural formula (II) with 1,1′-carbonyldiimidazole and then with alcohol represented by the following general structural formula (XVII):
R4OH (XVII)
wherein R4 is the same as defined above.
The pharmaceutically acceptable salts thereof can be obtained by treating carbonate benzoyl piperidine compounds with an anhydrous acid in a solution without further purification.
This procedure is summarized as set forth in Reaction Scheme IV below.
Details of the reaction conditions described in Reaction Scheme IV are as follows. For the conversion of the compounds (II) to the compound (XVI), the concentration of the starting material (II) is about 0.005 to 0.1 moles with 1,1′-carbonyldiimidazole ranging from about 2.0 to 3.0 equivalents. This reaction is preferably carried out at a temperature of 10 to 30° C. Without purification, the resulting intermediate is treated with 1 to 1,000 equivalents of alcohol represented by the general formula (XVII) at a temperature of 10 to 30° C. to give the compound of the general formula (XVI). For this carbonylation, an ethereal solvent such as diethyl ether and tetrahydrofuran, a halogenated hydrocarbon solvent such as dichloromethane and chloroform, or the mixture thereof may be used.
In Reaction Scheme IV, HX represents an acid capable of forming a pharmacologically useful salt with the basic nitrogen atom.
Representative examples of the compounds (I), (V), (VIII), (XIV) and (XVI) from scheme I, II, III and IV include the following structures:
The present invention includes methods of treating psychosis and cognition disorders in a mammal which comprises administering the composition of the compound of structural formula (I), (V), (VIII), (XIV) and (XVI) to a mammal in need of psychosis and cognition therapy.
This activity was examined through the anti-climbing behavior test, i.e. the test for suppressing the climbing behavior induced by apomorphine in mice. A designated amount of the test compound was intraperitoneally or orally administered to several groups of ICR CD strain male mice (body weight, 20 to 25 g; one group, 6 mice), and each of the animals was charged in an individual column cage of 12 cm in diameter and 14 cm in height having metal poles (each pole, 2 mm in diameter) vertically installed and arranged along the periphery with interval of 1 cm.
Compounds to be tested for antipsychotic activity are injected intraperitoneally or given orally at various time intervals, e.g. 30 minutes, 60 minutes, etc., prior to the apomorphine challenge at a screening dose of 0.1-60 mg/kg.
For evaluation of climbing, 3 readings are taken at 10, 20 and 30 minutes after apomorphine administration according to the following scale:
Score
Evaluation
0
All the paws were on the floor
1
One paw seized the pole of the cage
2
Two paws seized the pole of the cage
3
Three paws seized the pole of the cage
4
All four paws seized the pole of the cage
Mice consistently climbing before the injection of apomorphine will be discarded.
With full-developed apomorphine climbing, the animals are hanging on to the cage walls, rather motionless, over longer periods of time. By contrast, climbing due to mere motor stimulation usually only lasts a few seconds.
The climbing scores are individually totaled (maximal score: 12 per mouse over 3 readings) and the total score of the control group (vehicle intraperitoneally-apomorphine subcutaneously) is set to 100%. ED50 values with 95% confidence limits, calculated by a linear regression analysis, of some of the compounds of the instant invention as well as a standard antipsychotic agent are presented in Table I.
TABLE 1
Climbing Mouse Assay
ED 50 mg/kg
COMPOUND
i.p.
p.o.
carbamic acid 2-[4-(4-fluoro-benzoyl)-
4.8
9.7
piperidin-1-yl]-1-phenyl-ethyl ester
(S)-carbamic acid 2-[4-(4-fluoro-benzoyl)-
0.96
4.3
piperidin-1-yl]-1-phenyl-ethyl ester
(R)-carbamic acid 2-[4-(4-fluoro-benzoyl)-
17.8
46.2
piperidin-1-yl]-1-phenyl-ethyl ester
carbamic acid 1-(3-chloro-phenyl)-2-[4-(4-
0.56
0.94
fluoro-benzoyl)-piperidin-1-yl]-ethyl ester
carbamic acid 1-(3,4-dichloro-phenyl)-2-[4-(4-
0.32
0.48
fluoro-benzoyl)-piperidin-1-yl]-ethyl ester
benzyl-carbamic acid 2-[4-(4-fluoro-benzoyl)-
2.2
7.1
piperidin-1-yl]-phenyl-ethyl ester
carbamic acid 2-[4-(4-fluoro-benzoyl)-
2.6
—
piperidin-1-yl]-1-(3-nitro-phenyl)-ethyl ester
carbamic acid 2-[4-(4-fluoro-benzoyl)-
1.8
—
piperidin-1-yl]-1-(4-trifluoromethyl-phenyl)-
ethyl ester
carbamic acid 1-[4-(4-fluoro-benzoyl)-
2.0
8.5
piperidin-1-ylmethyl]-2-phenoxy-ethyl ester
carbamic acid Azepane-1-carboxylic acid 1-[4-
1.5
—
(4-fluoro-benzoyl)-piperidin-1-ylmethyl]-2-
phenoxy-ethyl ester
(4-fluoro-phenyl)-{1-[2-methoxy-2-(4-nitro-
5.9
51.2
phenyl)-ethyl]-piperidin-4-yl}-methanone
(S)-(4-fluoro-phenyl)-{1-[2-methoxy-2-(4-
4.5
16.9
nitro-phenyl)-ethyl]-piperidin-4-yl}-methanone
(R)-(4-fluoro-phenyl)-{1-[2-methoxy-2-(4-
24.2
—
nitro-phenyl)-ethyl]-piperidin-4-yl}-methanone
(4-fluoro-phenyl)-{1-[2-(4-isopropyl-phenyl)-
0.17
0.41
2-methoxy-ethyl]-piperidin-4-yl}-methanone
(S)-(4-fluoro-phenyl)-{1-[2-(4-isopropyl-
0.13
0.09
phenyl)-2-methoxy-ethyl]-piperidin-4-yl}-
methanone
{1-[2-(4-ethyl-phenyl)-2-methoxy-ethyl]-
0.87
piperidin-4-yl}-(4-fluoro-phenyl)-methanone
(S)-{1-[2-(4-ethyl-phenyl)-2-methoxy-ethyl]-
0.31
1 .2
piperidin-4-yl}-(4-fluoro-phenyl)-methanone
{1-[2-ethoxy-2-(4-nitro-phenyl)-ethyl]-
4.16
—
piperidin-4-yl}-(4-fluoro-phenyl)-methanone
(4-fluoro-phenyl)-{1-[2-(4-isopropyl-phenyl)-
3.1
4.7
2-[1,2,4]triazol-1-yl-ethyl]-piperidin-4-yl}-
methanone
{1-[2-(3,4-dimethyl-phenyl)-2-[1,2,4]triazol-1-
4.5
16.6
yl-ethyl]-piperidin-4-yl}-(4-fluoro-phenyl)
methanone
carbonic acid 1-(4-ethyl-phenyl)-2-[4-(4-
2.4
7.6
fluoro-benzoyl)-piperidin-1-yl]-ethyl ester
methyl ester
carbonic acid 1-(3-chloro-phenyl)-2-[4-(4-
6.2
—
fluoro-benzoyl)-piperidin-1-yl]-isopropyl ester
isopropyl ester
Risperidone (standard)
0.11
0.29
Clozapine (standard)
6.3
13.5
In therapeutic use as agents for various CNS disorders such as psychosis and cognition disorder, the compounds of the present invention, alone or in combination with pharmaceutically acceptable carrier, are administered to patients at a dosage of from 0.7 to 7,000 mg per day. For a normal human adult with a body weight of approximately 70 kg, the administration amount is translated into a daily dose of 0.01 to 100 mg per kg of body weight. The specific dosage employed, however, may vary depending upon the requirements of the patient, the severity of patient's condition and the activity of the compound. The determination of optimum dosages for a particular situation must clinically be done and is within the skill of the art.
In utilizing the compounds of the present -invention for the central nervous system, it is preferred to administer the compounds orally. Since the compounds absorb well orally, it usually will riot be necessary to resort to parenteral administration. For oral administration, the compounds having the general formula I is preferably combined with a pharmaceutical carrier. The ratio of the carrier to the compound of structural formula I is not critical to express the effects of the medicine on the central nervous system, and they can vary considerably depending on whether the composition is to be filled into capsules or formed into tablets. In tableting, various edible pharmaceutical carriers or the mixture thereof can be used. Suitable carriers, for example, are a mixture of lactose, diabasic calcium phosphate and/or corn starch. Other pharmaceutically acceptable ingredients can be further added, including lubricants such as magnesium stearate.
A better understanding of the present invention may be obtained in light of following examples which are set forth to illustrate, but are not to be construed to limit, the present invention.
EXAMPLE 1
Carbamic acid 2-[4-(4-fluoro-benzoyl)-piperidin-1-yl]-1-phenyl-ethyl ester; hydrochloride
A mixture of 4-(4-fluorobenzoyl)piperidine (5 mmol) and styrene oxide(5 mmol) was refluxed in 30 ml of isopropanol for 4 h. This solution was then concentrated on a rotary evaporator and diluted with ethyl acetate. This mixture was then washed with brine, the resulting organic layer was dried and concentrated in vacuo. The crude product was dissolved in THF(50 ml) and was added with 1,1′-carbonyl diimidazole (2 mmol) at 0° C. The reaction mixture was stirred at room temperature for 4 h, followed by the addition of excess ammonium hydroxide (10 ml) at 0° C. After 5 h stirring at room temperature, water was added to terminate the reaction. The organic layer was extracted 3 times with dichloromethane, dried and concentrated in vacuo. The residue was purified by column chromatography (ethyl acetate:hexane=1:2). The resulting carbamic acid 2-[4-(4-fluoro-benzoyl)-piperidin-1-yl]-1-phenyl-ethyl ester was dissolved in THF and the solution was treated with a solution of HCl in ethyl ether. The resulting precipitate was filtered to give carbamic acid 2-[4-(4-fluoro-benzoyl)-piperidin-1-yl]-1-phenyl-ethyl ester; hydrochloride.
1H-NMR (DMSO-d6, 200 MHz) δ10.9(br, 1H), 8.1(m, 2H), 7.4(m, 7H), 6.8(br, 2H), 6.0(d, 1H), 3.4(m, 7H), 2.0(m, 4H)
EXAMPLE 2
(S)-Carbamic acid 2-[4-(4-fluoro-benzoyl)-piperidin-1-yl]-1-phenyl-ethyl ester; hydrochloride
The procedure given in Example 1 was followed using (S)-styrene oxide as a reactant, instead of styrene oxide, to give (S)-carbamic acid 2-[4-(4-fluoro-benzoyl)-piperidin-1-yl]-1-phenyl-ethyl ester; hydrochloride.
1H-NMR (DMSO-d6, 200 MHz) δ10.9(br, 1H), 8.1(m, 2H), 7.4(m, 7H), 6.8(br, 2H), 6.0(d, 1H), 3.4(m, 7H), 2.0(m, 4H)
EXAMPLE 3
(R)-Carbamic acid 2-[4-(4-fluoro-benzoyl)-piperidin-1-yl]-1-phenyl-ethyl ester; hydrochloride
The procedure given in Example 1 was followed using (R)-styrene oxide as a reactant, instead of styrene oxide, to give (R)-carbamic acid 2-[4-(4-fluoro-benzoyl)-piperidin-1-yl]-1-phenyl-ethyl ester; hydrochloride.
1H-NMR (DMSO-d6, 200 MHz) δ10.9(br, 1H), 8.1(m, 2H), 7.4(m, 7H), 6.8(br, 2H), 6.0(d, 1H), 3.4(m, 7H), 2.0(m, 4H)
EXAMPLE 4
Carbamic acid 1-(3-chloro-phenyl)-2-[4-(4-fluoro-benzoyl)-piperidin-1-yl]-ethyl ester; hydrochloride
The procedure given in Example 1 was followed using 3-chlorostyrene oxide as a reactant, instead of styrene oxide, to give carbamic acid 1-(3-chloro-phenyl)-2-[4-(4-fluoro-benzoyl)-piperidin-1-yl]-ethyl ester; hydrochloride.
1H-NMR (DMSO-d6, 200 MHz) δ10.6(br, 1H), 8.1(m, 2H), 7.4(m, 7H), 6.85(br, 2H), 6.0(d, 1H), 3.4(m, 7H), 2.0(m, 4H)
EXAMPLE 5
Carbamic acid 1-(3,4-dichloro-phenyl)-2-[4-(4-fluoro-benzoyl)-piperidin-1-yl]-ethyl ester; hydrochloride
The procedure given in Example 1 was followed using 3,4-dichlorostyrene oxide as a reactant, instead of styrene oxide, to give carbamic acid 1-(3,4-dichloro-phenyl)-2-[4-(4-fluoro-benzoyl)-piperidin-1-yl]-ethyl ester; hydrochloride.
1H-NMR (DMSO-d6, 200 MHz) δ10.7(br, 1H), 8.1(m, 2H), 7.7(m, 2H), 7.4(m, 3H), 6.9(br, 2H), 6.0(d, 1H), 3.4(m, 7H), 2.0(m, 4H)
EXAMPLE 6
Benzyl-carbamic acid 2-[4-(4-fluoro-benzoyl)-piperidin-1-yl]-1-phenyl-ethyl ester; hydrochloride
The procedure given in Example 1 was followed using benzyl amine as a reactant, instead of ammonium hydroxide, to give benzyl-carbamic acid 2-[4-(4-fluoro-benzoyl)-piperidin-1-yl]-1-phenyl-ethyl ester; hydrochloride.
1H-NMR (DMSO-d6, 200 MHz) δ9.5(br, 1H), 8.1(m, 3H), 7.3.(m, 12H), 6.0(d, 1H), 3.6(m, 9H), 2.0(m, 4H)
EXAMPLE 7
Carbamic acid 2-[4-(4-fluoro-benzoyl)-piperidin-1-yl]-1-(3-nitro-phenyl)-ethyl ester; hydrochloride
The procedure given in Example 1 was followed using 3-nitrostyrene oxide as a reactant, instead of styrene oxide, to give carbamic acid 2-[4-(4-fluoro-benzoyl)-piperidin-1-yl]-1-(3-nitro-phenyl)-ethyl ester; hydrochloride.
1H-NMR (DMSO-d6, 200 MHz) δ10.8(br, 1H), 8.2(m, 4H), 7.8(m, 2H), 7.4(m, 2H), 6.95(br, 2H), 6.2(d, 1H), 3.6(m, 7H), 2.0(m, 4H)
EXAMPLE 8
Carbamic acid 2-[4-(4-fluoro-benzoyl)-piperidin-1-yl]-1-(4-trifluoromethyl-phenyl)-ethyl ester; hydrochloride
The procedure given in Example 1 was followed using 4-trifluoromethylstyrene oxide as a reactant, instead of styrene oxide, to give carbamic acid 2-[4-(4-fluoro-benzoyl)-piperidin-1-yl]-1-(4-trifluoromethyl-phenyl)-ethyl ester; hydrochloride.
1H-NMR (DMSO-d6, 200 MHz) δ10.8(br, 1H), 8.15(m, 2H), 7.8(d, 2H), 7.65(d, 2H), 7.4(m, 2H), 6.9(br, 2H), 6.15(d, 1H), 3.5(m, 7H), 2.0(m, 4H)
EXAMPLE 9
Carbamic acid 2-[4-(4-fluoro-benzoyl)-piperidin-1-yl]-1-(4-fluoro-phenyl)-ethyl ester; hydrochloride
The procedure given in Example 1 was followed using 4-fluorostyrene oxide as a reactant, instead of styrene oxide, to give carbamic acid 2-[4-(4-fluoro-benzoyl)-piperidin-1-yl]-1-(4-fluoro-phenyl)-ethyl ester; hydrochloride.
1H-NMR (DMSO-d6, 200 MHz) δ10.45(br, 1H), 8.1(m, 2H), 7.35(m, 6H), 6.8(br, 2H), 6.0(d, 1H), 3.4(m, 7H), 2.0(m, 4H)
EXAMPLE 10
Carbamic acid 1-(4-chloro-phenyl)-2-[4-(4-fluoro-benzoyl)-piperidin-1-yl]-ethyl ester; hydrochloride
The procedure given in Example 1 was followed using 4-chlorostyrene oxide as a reactant, instead of styrene oxide, to give carbamic acid 1-(4-chloro-phenyl)-2-[4-(4-fluoro-benzoyl)-piperidin-1-yl]-ethyl ester; hydrochloride.
1H-NMR (DMSO-d6, 200 MHz) δ0.5(br, 1H), 8.1(m, 2H), 7.4(m, 6H), 6.8(br, 2H), 6.0(d, 1H), 3.4(m, 7H), 2.0(m, 4H)
EXAMPLE 11
(S)-Carbamic acid 1-(4-chloro-phenyl)-2-[4-(4-fluoro-benzoyl)-piperidin-1-yl]-ethyl ester; hydrochloride
The procedure given in Example 1 was followed using (S)-4-chlorostyrene oxide as a reactant, instead of styrene oxide, to give (S)-carbamic acid 1-(4-chloro-phenyl)-2-[4-(4-fluoro-benzoyl)-piperidin-1-yl]-ethyl ester; hydrochloride.
1H-NMR (DMSO-d6, 200 MHz) δ10.5(br, 1H), 8.1(m, 2H), 7.4(m, 6H), 6.8(br, 2H), 6.0(d, 1H), 3.4(m, 7H), 2.0(m, 4H)
EXAMPLE 12
(R)-Carbamic acid 1-(4-chloro-phenyl)-2-[4-(4-fluoro-benzoyl)-piperidin-1-yl]-ethyl ester; hydrochloride
The procedure given in Example 1 was followed using (R)-4-chlorostyrene oxide as a reactant, instead of styrene oxide, to give (R)-carbamic acid 1-(4-chloro-phenyl)-2-[4-(4-fluoro-benzoyl)-piperidin-1-yl]-ethyl ester; hydrochloride.
1H-NMR (DMSO-d6, 200 MHz) δ10.5(br, 1H), 8.1(m, 2H), 7.4(m, 6H), 6.8(br, 2H), 6.0(d, 1H), 3.4(m, 7H), 2.0(m, 4H)
EXAMPLE 13
Carbamic acid 1-(2-chloro-phenyl)-2-[4-(4-fluoro-benzoyl)-piperidin-1-yl]-ethyl ester; hydrochloride
The procedure given in Example 1 was followed using 2-chlorostyrene oxide as a reactant, instead of styrene oxide, to give carbamic acid 1-(2-chloro-phenyl)-2-[4-(4-fluoro-benzoyl)-piperidin-1-yl]-ethyl ester; hydrochloride.
1H-NMR (DMSO-d6, 200 MHz) δ10.5(br, 1H), 8.1(m, 2H), 7.4(m, 6H), 6.9(br, 2H), 6.2(d, 1H), 3.5(m, 7H), 2.0(m, 4H)
EXAMPLE 14
Carbamic acid 1-(2,4-dichloro-phenyl)-2-[4-(4-fluoro-benzoyl)-piperidin-1-yl]-ethyl ester; hydrochloride
The procedure given in Example 1 was followed using 2,4-dichlorostyrene oxide as a reactant, instead of styrene oxide, to give carbamic acid 1-(2,4-dichloro-phenyl)-2-[4-(4-fluoro-benzoyl)-piperidin-1-yl]-ethyl ester; hydrochloride.
1H-NMR (DMSO-d6, 200 MHz) δ11.2(br, 1H), 8.0(m, 2H), 7.3(m, 3H), 7.1(s, 2H), 6.5(br, 2H), 6.2(d, 1H), 3.4(m, 7H), 2.0(m, 4H)
EXAMPLE 15
Carbamic acid 2-[4-(4-fluoro-benzoyl)-piperidin-1-yl]-1-o-tolyl-ethyl ester
The procedure given in Example 1 was followed using 2-methylstyrene oxide as a reactant, instead of styrene oxide, to give carbamic acid 2-[4-(4-fluoro-benzoyl)-piperidin-1-yl]-1-o-tolyl-ethyl ester.
1H-NMR (CDCl3, 200 MHz) δ7.95(m, 2H), 7.35(m, 1H), 7.15(m, 5H), 6.1(d, 1H), 4.85(br, 2H), 3.0(m, 4H), 2.5(dd, 1H), 2.4(s, 3H), 2.3(m, 2H), 1.8(m, 4H)
EXAMPLE 16
Carbamic acid 2-[4-(4-fluoro-benzoyl)-piperidin-1-yl]-1-p-tolyl-ethyl ester
The procedure given in Example 1 was followed using 4-methylstyrene oxide as a reactant, instead of styrene oxide, to give carbamic acid 2-[4-(4-fluoro-benzoyl)-piperidin-1-yl]-1-p-tolyl-ethyl ester.
1H-NMR (CDCl3, 200 MHz) δ7.95(m, 2H), 7.2(m, 6H), 5.85(dd, 1H), 4.7(br, 2H), 3.0(m, 4H), 2.6(dd, 1H), 2.35(s, 3H), 2.25(m, 2H), 1.8(m, 4H)
EXAMPLE 17
Carbamic acid 2-[4-(4-fluoro-benzoyl)-piperidin-1-yl]-1-(4-nitro-phenyl)-ethyl ester
The procedure given in Example 1 was followed using 4-nitrostyrene oxide as a reactant, instead of styrene oxide, to give carbamic acid 2-[4-(4-fluoro-benzoyl)-piperidin-1-yl]-1-(4-nitro-phenyl)-ethyl ester.
1H-NMR (CDCl3, 200 MHz) δ8.2(d, 21H), 7.95(m, 2H), 7.5(d, 2H), 7.1(m, 2H), 5.85(dd, 1H), 4.75(br, 2H), 3.0(m, 4H), 2.6(dd, 1 H), 2.3(m, 2H), 1.8(m, 4H)
EXAMPLE 18
Carbamic acid 1-(4-tert-butyl-phenyl)-2-[4-(4-fluoro-benzoyl)-piperidin-1-yl]-ethyl ester
The procedure given in Example 1 was followed using 4-tert-butylstyrene oxide as a reactant, instead of styrene oxide, to give carbamic acid 1-(4-tert-butyl-phenyl)-2-[4-(4-fluoro-benzoyl)-piperidin-1-yl]-ethyl ester.
1H-NMR (CDCl3, 200 MHz) δ8.0(d, 2H), 7.35(m, 4H), 7.15(m, 2H), 5.85(dd, 1H), 4.95(s, 2H), 3.1(m, 4H), 2.6(dd, 1H), 2.3(m, 2H), 1.85(m, 4H)
EXAMPLE 19
Carbamic acid 2-[4-(4-fluoro-benzoyl)-piperidin-1-yl]-1-naphthalen-2-yl-ethyl ester
The procedure given in Example 1 was followed using 2-naphthalene oxide as a reactant, instead of styrene oxide, to give carbamic acid 2-[4-(4-fluoro-benzoyl)-piperidin-1-yl]-1-naphthalen-2-yl-ethyl ester.
1H-NMR (DMSO-d6, 200 MHz) δ11.2(br, 1H), 7.95(m, 6H), 7.5(m, 3H), 7.3(m, 2H), 6.6(br, 2H), 5.85(d, 1H), 2.95(m, 2H), 2.8(dd, 1H), 2.6(dd, 1H), 2.5(s, 1H), 2.35(m, 2H), 1.6(m, 4H)
EXAMPLE 20
Carbamic acid 2-(4-benzoyl-piperidin-1-yl)-1-(2-chloro-phenyl)-ethyl ester; hydrochloride
The procedure given in Example 1 was followed using 2-chlorostyrene oxide and 4-benzoylpiperidine as reactants, instead of styrene oxide and 4-(4-fluorobenzoyl)piperidine, to give carbamic acid 2-(4-benzoyl-piperidin-1-yl)-1-(2-chloro-phenyl)-ethyl ester; hydrochloride.
1H-NMR (DMSO-d6, 200 MHz) δ11.05(br, 1H), 7.90(m, 2H), 7.45(m, 4H), 7.3(m, 2H), 6.5(br, 2H), 6.25(d, 1H), 3.4(m, 7H), 2.0(m, 4H)
EXAMPLE 21
Carbamic acid 1-(2-chloro-phenyl)-2-[4-(4-methoxy-benzyl)-piperidin-1-yl]-ethyl ester; hydrochloride
The procedure given in Example 1 was followed using 2-chlorostyrene oxide and 4-(4-methoxybenzoyl)piperidine as reactants, instead of styrene oxide and 4-(4-fluorobenzoyl)piperidine, to give carbamic acid 1-(2-chloro-phenyl)-2-[4-(4-methoxy-benzoyl)-piperidin-1-yl]-ethyl ester; hydrochloride.
1H-NMR (DMSO-d6, 200 MHz) δ10.8(br, 1H), 8.0(m, 2H), 7.4(m, 4H), 7.0(m, 2H), 6.85(br, 2H), 6.2(d, 1H), 3.8(s, 3H), 3.4(m, 7H), 2.0(m, 4H)
EXAMPLE 22
Carbamic acid 2-[4-(4-tert-butyl-benzoyl)-piperidin-1-yl]-1-(2-chloro-phenyl)-ethyl ester
The procedure given in Example 1 was followed using 2-chlorostyrene oxide and 4-(4-tert-butylbenzoyl)piperidine as reactants, instead of styrene oxide and 4-(4-fluorobenzoyl)piperidine, to give carbamic acid 2-[4-(4-tert-butyl-benzoyl)-piperidin-1-yl]-1-(2-chloro-phenyl)-ethyl ester.
1H-NMR (CDCl3, 200 MHz) δ7.9(d, 2H), 7.45(m, 3H), 7.3(m, 3H), 6.25(dd, 1H), 5.0(s, 2H), 3.2(m, 2H), 2.95(dd, 1H), 2.8(dd, 1H), 2.65(dd, 1H), 2.3(m, 2H), 1.8(m, 4H), 1.35(s, 9H)
EXAMPLE 23
Carbamic acid 2-[4-(4-chloro-benzoyl)-piperidin-1-yl]-1-(2-chloro-phenyl)-ethyl ester; hydrochloride
The procedure given in Example 1 was followed using 2-chlorostyrene oxide and 4-(4-chlorobenzoyl)piperidine as reactants, instead of styrene oxide and 4-(4-fluorobenzoyl)piperidine, to give carbamic acid 2-[4-(4-chloro-benzoyl)-piperidin-1-yl]-1-(2-chloro-phenyl)-ethyl ester; hydrochloride.
1H-NMR (CD3OD, 200 MHz) δ8.0(d, 2H), 7.45(m, 6H), 6.4(d, 1H), 5.9(br, 2H), 3.6(m, 7H), 2,15(m, 4H)
EXAMPLE 24
Azepane-1-carboxylic acid 1-[4-(4-fluoro-benzoyl)-piperidin-1-ylmethyl]-2-phenoxy-ethyl ester
The procedure given in Example 24 was followed using hexamethyleneimine as a reactant, instead of ammonium hydroxide, to give azepane-1-carboxylic acid 1-[4-(4-fluoro-benzoyl)-piperidin-1-ylmethyl]-2-phenoxy-ethyl ester.
1H-NMR (CDCl3, 200 MHz) δ7.97(dd, 2H), 7.18(m, 4H), 6.86(dd, 2H), 5.2(m, 1H), 4.18(m, 2H), 3.4(m, 4H), 3.2(m, 1H), 3.04(m, 2H), 2.7(d, 2H), 2.3(m, 2H), 1.8(m, 4H), 1.6(m, 8H)
EXAMPLE 25
Carbamic acid 1-[4-(4-fluoro-benzoyl)-piperidin-1-ylmethyl]-3-phenyl-propyl ester
The procedure given in Example 1 was followed using 2-phenethyl-oxirane as a reactant, instead of styrene oxide, to give carbamic acid 1-[4-(4-fluoro-benzoyl)-piperidin-1-ylmethyl]-3-phenyl-propyl ester.
1H-NMR (CDCl3, 200 MHz) δ7.95(dd, 2H), 7.15(m, 7H), 5.17(s, 2H), 4.95(m, 1H), 3.15(m, 1H), 2.98(m, 2H), 2.65(m, 2H), 2.55(dd, 1H), 2.4(dd, 1H), 2.16(m, 2H), 1.85(m, 6H)
EXAMPLE 26
Piperidine-1-carboxylic acid 1-[4-(4-fluoro-benzoyl)-piperidin-1-ylmethyl]-3-phenyl-propyl ester
The procedure given in Example 1 was followed using 2-phenethyl-oxirane and piperidine as reactants, instead of styrene oxide and ammonium hydroxide, to give piperidine-1-carboxylic acid 1-[4-(4-fluoro-benzoyl)-piperidin-1-ylmethyl]-3-phenyl-propyl ester.
1H-NMR (CDCl3, 200 MHz) δ7.95(dd, 2H), 7.15(m, 7H), 4.95(m, 1H), 3.4(s, 4H), 3.15(m, 1H), 2.98(m, 2H), 2.65(m, 2H), 2.55(dd, 1H), 2.45(dd, 1H), 2.2(m, 2H), 1.95(m, 2H), 1.8(m, 4H), 1.57(m, 6H)
EXAMPLE 27
Carbamic acid 1-[4-(4-fluoro-benzoyl)-piperidin-1-ylmethyl]-2-phenoxy-ethyl ester; hydrochloride
A mixture of 4-(4-fluorobenzoyl)piperidine (5 mmol) and 1,2-epoxy-3-phenoxypropane (5 mmol) was refluxed in 30 ml of isopropanol for 4 h. This solution was then concentrated on a rotary evaporator and diluted with ethyl acetate. This mixture was then washed with brine, the resulting organic layer was dried and concentrated in vacuo to give a solid. This was recrystallized in a solution mixture of n-hexane and ethyl acetate to give a white solid. This was dissolved in THF (50 ml) and was added with 1,1′-carbonyl diimidazole (10 mmol) at 0° C. The reaction mixture was stirred at room temperature for 4 h, followed by the addition of excess ammonium hydroxide (10 ml) at 0° C. After 5 h stirring at room temperature, water was added to terminate the reaction. The organic layer was extracted 3 times with dichloromethane, dried and concentrated in vacuo. The residue was purified by column chromatography (ethyl acetate:hexane=1:2). The resulting carbamic acid 1-[4-(4-fluoro-benzoyl)-piperidin-1-ylmethyl]-2-phenoxy-ethyl ester was dissolved in THF and the solution was treated with a solution of HCl in ethyl ether. The resulting precipitate was filtered to give carbamic acid 1-[4-(4-fluoro-benzoyl)-piperidin-1-ylmethyl]-2-phenoxy-ethyl ester; hydrochloride.
1H-NMR (DMSO-d6, 200 MHz) δ10.3(br, 1H), 8.1(m, 2H), 7.35(m, 4H), 6.95(m, 3H), 6.85(br, 2H), 5.35(m, 1H), 4.15(m, 2H), 3.5(m, 7H), 2.0(m, 4H)
EXAMPLE 28
Carbamic acid 2-(4-chloro-phenoxy)-1-[4-(4-fluoro-benzoyl)-piperidin-1-ylmethyl]-ethyl ester
The procedure given in Example 27 was followed using 4-chlorophenyl glycidyl ether as a reactant, instead of 1,2-epoxy-3-phenoxypropane, to give carbamic acid 2-(4-chloro-phenoxy)-1-[4-(4-fluoro-benzoyl)-piperidin-1-ylmethyl]-ethyl ester.
1H-NMR (CDCl3, 200 MHz) δ7.9(dd, 2H), 7.15(m, 4H), 6.8(d, 2H), 5.9(br, 2H), 5.1(m, 1H), 4.1(m, 2H), 3.2(m, 1H), 3.0(m, 2H), 2.7(d, 2H), 2.3(m, 2H), 1.75(m, 4H)
EXAMPLE 29
Carbamic acid 1-[4-(4-fluoro-benzoyl)-piperidin-1-ylmethyl]-2-(4-methoxy-phenoxy)-ethyl ester
The procedure given in Example 27 was followed using glycidyl 4-methoxyphenyl ether as a reactant, instead of 1,2-epoxy-3-phenoxypropane, to give carbamic acid 1-[4-(4-fluoro-benzoyl)-piperidin-1-ylmethyl]-2-(4-methoxy-phenoxy)-ethyl ester.
1H-NMR (CDCl3, 200 MHz) δ7.95(dd, 2H), 7.15(m, 2H), 6.85(m, 4H), 5.15(m, 1H), 5.1(br, 2H), 4.1(m, 2H), 3.75(s, 3H), 3.2(m, 1 H), 3.05(m, 2H), 2.75(d, 2H), 2.35(m, 2H), 1.85(m, 4H)
EXAMPLE 30
Carbamic acid 2-(4-tert-butyl-phenoxy)-1-[4-(4-fluoro-benzoyl)-piperidin-1-ylmethyl]-ethyl ester
The procedure given in Example 27 was followed using 4-tert-butyl-phenyl glycidyl ether as a reactant, instead of 1,2-epoxy-3-phenoxypropane, to give carbamic acid 2-(4-tert-butyl-phenoxy)-1-[4-(4-fluoro-benzoyl)-piperidin-1-ylmethyl]-ethyl ester
1H-NMR (CDCl3, 200 MHz) δ7.95(dd, 2H), 7.3(d, 2H), 7.15(t, 2H), 6.9(d, 2H), 5.25(br, 2H), 5.2(m, 1H), 4.15(m, 2H), 3.2(m, 1H), 3.05(m, 2H), 2.7(d, 2H), 1.8(m, 4H), 1.3(s, 9H)
EXAMPLE 31
Pyrrolidine-1-carboxylic acid 1-[4-(4-fluoro-benzoyl)-piperidin-1-ylmethyl]-2-phenoxy-ethyl ester
The procedure given in Example 27 was followed using pyrrolidine as a reactant, instead of ammonium hydroxide, to give pyrrolidine-1-carboxylic acid 1-[4-(4-fluoro-benzoyl)-piperidin-1-ylmethyl]-2-phenoxy-ethyl ester.
1H-NMR (CDCl3, 200 MHz) δ7.99(dd, 2H), 7.17(m, 4H), 6.86(d, 2H), 5.23(m, 1H), 4.18(m, 2H), 3.35(m, 5H), 3.1(m, 2H), 2.82(d, 2H), 2.45(m, 2H), 1.9(m, 8H)
EXAMPLE 32
Piperidine-1-carboxylic acid 1-[4-(4-fluoro-benzoyl)-piperidin-1-ylmethyl]-2-phenoxy-ethyl ester
The procedure given in Example 27 was followed using piperidine as a reactant, instead of ammonium hydroxide, to give piperidine-1-carboxylic acid 1-[4-(4-fluoro-benzoyl)-piperidin-1-ylmethyl]-2-phenoxy-ethyl ester.
1H-NMR (CDCl3, 200 MHz) δ7.99(dd, 2H), 7.18(m, 4H), 6.86(dd, 2H), 5.18(m, 1H), 4.18(m, 2H), 3.4(m, 4H), 3.2(m, 1H), 3.04(m, 2H), 2.7(d, 2H), 2.3(m, 2H), 1.8(m, 4H), 1.55(m, 6H)
EXAMPLE 33
Morpholine-4-carboxylic acid 1-[4-(4-fluoro-benzoyl)-piperidin-1-ylmethyl]-2-phenoxy-ethyl ester
The procedure given in Example 27 was followed using morpholine as a reactant, instead of ammonium hydroxide, to give morpholine-4-carboxylic acid 1-[4-(4-fluoro-benzoyl)-piperidin-1-ylmethyl]-2-phenoxy-ethyl ester.
1H-NMR (CDCl3, 200 MHz) δ7.98(dd, 2H), 7.2(m, 4H), 6.86(m, 2H), 5.2(m, 1H), 4.18(m, 2H), 3.65(m, 4H), 3.5(m, 4H), 3.2(m, 1H), 3.07(m, 2H), 2.73(d, 2H) 2.36(m, 2H), 1.85(m, 4H)
EXAMPLE 34
(4-Fluoro-phenyl)-{1-[2-methoxy-2-(4-nitro-phenyl)-ethyl]-piperidin-4yl}-methanone; hydrochloride
A mixture of 4-(4-fluorobenzoyl)piperidine(5 mmol) and 2-(4-nitro-phenyl)oxirane (5 mmol) was refluxed in 30 ml of isopropanol for 4 h. This solution was then concentrated on a rotary evaporator and diluted with ethyl acetate. This mixture was then washed with brine, the resulting organic layer was dried and concentrated in vacuo. The crude product was dissolved in dichloromethane (50 ml) and was added with methanesulfonyl chloride (2 eq.) and triethylamine (3 eq.) at 0° C. The reaction mixture was stirred at room temperature for 1 h. This solution was then concentrated on a rotary evaporator and dissolved in THF (50 ml), added triethylamine (3 eq.), followed by the addition of excess methanol (>10 eq.). After 12 hours stirring at 80° C., this solution is concentrated on a rotary evaporator and diluted with ethyl acetate. The organic layer was extracted 3 times with dichloromethane, dried and concentrated in vacuo. The residue was purified by column chromatography (ethyl acetate:hexane=1:1). The resulting (4-fluoro-phenyl)-{1-[2-methoxy-2-(4-nitro-phenyl)-ethyl]-piperidin-4-yl}-methanone was dissolved in dichloromethane and the solution was treated with a solution of HCl in ethyl ether. The resulting precipitate was filtered to give (4-fluoro-phenyl)-{1-[2-methoxy-2-(4-nitro-phenyl)-ethyl]-piperidin-4-yl}-methanone; hydrochloride
1H-NMR (DMSO-d6, 200 MHz) δ11.1(br, 1H), 8.2(m, 2H), 8.0(m, 2H), 7.5(m, 2H), 7.2(m, 2H), 4.5(m, 1H), 3.4(s, 3H), 3.2(m, 2H), 2.9(m, 1H), 2.8(m, 1H), 2.5(m, 1H), 2.3(m, 2H), 1.8(m, 4H)
EXAMPLE 35
(S)-(4-Fluoro-phenyl)-{1-[2-methoxy-2-(4-nitro-phenyl)-ethyl]-piperidin-4-yl}-methanone
The procedure given in Example 34 was followed using (S)-4-nitrostyrene oxide as a reactant, instead of 2-(4-nitro-phenyl)oxirane, to give (S)-(4-fluoro-phenyl)-{1-[2-methoxy-2-(4-nitro-phenyl)-ethyl]-piperidin-4-yl}-methanone.
1H-NMR (CDCl3, 200 MHz) δ8.3(m, 2H), 8.0(m, 2H), 7.5(m, 2H), 7.2(m, 2H), 4.5(m, 1H), 3.5(s, 3H), 3.2(m, 2H), 2.9(m, 1H), 2.8(m, 1H), 2.5(m, 1H), 2.3(m, 2H), 1.8(m, 4H)
EXAMPLE 36
(R)-(4-Fluoro-phenyl)-{1-[2-methoxy-2-(4-nitro-phenyl)-ethyl]-piperidin-4-yl}-methanone
The procedure given in Example 34 was followed using (R)-4-nitrostyrene oxide as a reactant, instead of 2-(4-nitro-phenyl)oxirane, to give (R)-(4-fluoro-phenyl)-{1-[2-methoxy-2-(4-nitro-phenyl)-ethyl]-piperidin-4-yl}-methanone.
1H-NMR (CDCl3, 200 MHz) δ8.2(m, 2H), 8.1(m, 2H), 7.7(m, 2H), 7.3(m, 2H), 4.5(m, 1H), 3.4(s, 3H), 3.3(m, 2H), 2.9(m, 1H), 2.8(m, 1H), 2.5(m, 1H), 2.3(m, 2H), 1.8(m, 4H)
EXAMPLE 37
{1-[2-Ethoxy-2-(4-nitro-phenyl)-ethyl]-piperidin-4-yl}-(4-fluoro -1phenyl)-methanone
The procedure given in Example 34 was followed using ethanol as a reactant, instead of methanol, to give {1-[2-ethoxy-2-(4-nitro-phenyl)-ethyl]-piperidin-4-yl}-(4-fluoro-phenyl)-methanone.
1H-NMR (CDCl3, 200 MHz) δ8.3(m, 2H), 8.0(m, 2H), 7.7(m, 2H), 7.2(m, 2H), 4.5(m, 1H), 3.4(q, 2H), 3.2(m, 2H), 2.9(m, 1H), 2.8(m, 1H), 2.5(m, 1H), 2.3(m, 2H), 1.8(m, 4H), 1.2(t, 3H)
EXAMPLE 38
(4-Fluoro-phenyl)-{1-[2-isopropoxy-2-(4-nitro-phenyl)-ethyl]-piperidin-4-yl}-methanone
The procedure given in Example 34 was followed using isopropanol as a reactant, instead of methanol, to give (4-fluoro-phenyl)-{1-[2-isopropoxy-2-(4-nitro-phenyl)-ethyl]-piperidin-4-yl}-methanone.
1H-NMR (CDCl3, 200 MHz) δ8.2(m, 2H), 8.0(m, 2H), 7.6(m, 2H), 7.1(m, 2H), 4.7(m, 1H), 3.5(m, 1H), 3.2(m, 2H), 2.9(m, 1H), 2.8(m, 1H), 2.5(m, 1H), 2.3(m, 2H), 1.8(m, 4H), 1.1(dd, 6H)
EXAMPLE 39
{1-[2-Cyclopentyloxy-2-(4-nitro-phenyl)-ethyl]-piperidin-4-yl}-(4-fluoro-phenyl)-methanone
The procedure given in Example 34 was followed using cyclopentanol as a reactant, instead of methanol, to give {1-[2-cyclopentyloxy-2-(4-nitro-phenyl)-ethyl]-piperidin-4-yl}-(4-fluoro-phenyl)-methanone.
1H-NMR (CDCl3, 200 MHz) δ8.2(m, 2H), 8.0(m, 2H), 7.5(m, 2H), 7.1(m, 2H), 4.6(m, 1H), 3.8(m, 1H), 3.2(m, 2H), 2;9(m, 1H), 2.8(m, 1H), 2.5(m, 1H), 2.3(m, 2H), 1.7(br, 14H)
EXAMPLE 40
{1-[2-Benzyloxy-2-(4-nitro-phenyl)-ethyl]-piperidin-4-yl}-(4-fluoro-phenyl)-methanone
The procedure given in Example 34 was followed using benzyl alcohol as a reactant, instead of methanol, to give {1-[2-benzyloxy-2-(4-nitro-phenyl)-ethyl]-piperidin-4-yl}-(4-fluoro-phenyl)-methanone.
1H-NMR (CDCl3, 200 MHz) δ8.3(m, 2H), 8.0(m, 2H), 7.6(m, 2H), 7.3(m, 5H), 7.1(m, 2H), 4.7(m, 2H), 4.4(m, 1H), 3.2(m, 2H), 2.9(m, 2H), 2.5(m, 1H), 2.4(m 1.8(m, 4H)
EXAMPLE 41
{1-[2-(4-Ethyl-phenyl)-2-methoxy-ethyl]-piperidin-4-yl}-(4-fluoro-phenyl)-methanone
The procedure given in Example 34 was followed using 4-ethylstyrene oxide as a reactant, instead of 2-(4-nitro-phenyl)oxirane, to give {1-[2-(4-ethyl-phenyl)-2-methoxy-ethyl]-piperidin-4-yl}-(4-fluoro-phenyl)-methanone.
1H-NMR (CDCl3, 200 MHz) δ8.0(m, 2H), 7.2(m, 6H), 4.4(m, 1H), 3.3(s, 3H), 3.1(m, 3H), 2.8(m, 1H), 2.7(q, 2H), 2.5(m, 1H), 2.3(m, 2H), 1.8(m, 4H), 1.2(t, 3H).
EXAMPLE 42
(S)-{1-[2-(4-Ethyl-phenyl)-2-methoxy-ethyl]-piperidin-4-yl}-(4-fluoro-phenyl)-methanone
The procedure given in Example 34 was followed using (S)-4-ethylstyrene oxide as a reactant, instead of 2-(4-nitro-phenyl)oxirane, to give (S)-{1-[2-(4-ethyl-phenyl)-2-methoxy-ethyl]-piperidin-4-yl}-(4-fluoro-phenyl)-methanone.
1H-NMR (CDCl3, 200 MHz) δ8.0(m, 2H), 7.2(m, 6H), 4.4(m, 1H), 3.3(s, 3H), 3.1(m, 3H), 2.8(m, 1H), 2.7(q, 2H), 2.5(m, 1H), 2.3(m, 2H), 1.8(m, 4H), 1.2(t, 3H).
EXAMPLE 43
(4-Fluoro-phenyl)-{1-[2-(4-isopropyl-phenyl)-2-methoxy-ethyl]-piperidin-4-yl}-methanone
The procedure given in Example 34 was followed using 4-isopropylstyrene oxide as a reactant, instead of 2-(4-nitro-phenyl)oxirane, to give (4-fluoro-phenyl)-{1-[2-(4-isopropyl-phenyl)-2-methoxy-ethyl]-piperidin-4-yl}-methanone.
1H-NMR (CDCl3, 200 MHz) δ8.0(m, 2H), 7.2(m, 6H), 4.4(m, 1H), 3.3(s, 3H), 3.2(m, 3H), 2.9(m, 2H), 2.5(m, 1H), 2.3(m, 2H), 1.8(m, 4H)
EXAMPLE 44
(S)-(4-Fluoro-phenyl)-{1-[2-(4-isopropyl-phenyl)-2-methoxy-ethyl]-piperidin-4-yl}-methanone
The procedure given in Example 34 was followed using (S)-4-isopropylstyrene oxide as a reactant, instead of 2-(4-nitro-phenyl)oxirane, to give (S)-(4-fluoro-phenyl)-{1-[2-(4-isopropyl-phenyl)-2-methoxy-ethyl]-piperidin-4-yl}-methanone.
1H-NMR (CDCl3, 200 MHz) δ8.0(m, 2H), 7.2(m, 6H), 4.4(m, 1H), 3.3(s, 3H), 3.2(m, 3H), 2.9(m, 2H), 2.5(m, 1H), 2.3(m, 2H), 1.8(m, 4H)
EXAMPLE 45
(4-Fluoro-phenyl)-[1-(2-methoxy-2-naphthalen-2-yl-ethyl)-piperidin-4-yl]-methanone; hydrochloride
The procedure given in Example 34 was followed using 2-naphthalene oxide as a reactant, instead of 2-(4-nitro-phenyl)oxirane, to give (4-fluoro-phenyl)-[1-(2-methoxy-2-naphthalen-2-yl-ethyl)-piperidin-4-yl]-methanone; hydrochloride
1H-NMR (DMSO-d6, 200 MHz) δ10.8(br, 1H), 8.0(m, 2H), 7.9(m, 4H), 7.5(m, 3H), 7.1(m, 2H), 4.5(m, 1H), 3.4(s, 3H), 3.2(m, 4H), 2.9(m, 1H), 2.6(m, 1H), 2.3(m, 1H), 1.8(m, 4H)
EXAMPLE 46
(S)-(4-Fluoro-phenyl)-[1-(2-methoxy-2-naphthalen-2-yl-ethyl)-piperidin-4-yl]-methanone; hydrochloride
The procedure given in Example 34 was followed using (S)-2-naphthalene oxide as a reactant, instead of 2-(4-nitro-phenyl)oxirane, to give (S)-(4-fluoro-phenyl)-[1-(2-methoxy-2-naphthalen-2-yl-ethyl)-piperidin-4-yl]-methanone; hydrochloride.
1H-NMR (DMSO-d6, 200 MHz) δ10.8(br, 1H), 8.1(m, 2H), 7.9(m, 4H), 7.5(m, 3H), 7.1(m, 2H), 4.5(m, 1H), 3.4(s, 3H), 3.1(m, 4H), 2.9(m, 1H), 2.6(m, 1H), 2.4(m, 1H), 1.8(m, 4H)
EXAMPLE 47
{1-[2-(3,4-Dimethyl-phenyl)-2-methoxy-ethyl]-piperidin-4-yl}-(4-fluoro-phenyl)-methanone
The procedure given in Example 34 was followed using 3,4-dimethylstyrene oxide as a reactant, instead of 2-(4-nitro-phenyl)oxirane, to give {-[2-(3,4-dimethyl-phenyl)-2-methoxy-ethyl]-piperidin-4-yl}-(4-fluoro-phenyl)-methanone.
1H-NMR (CDCl3, 200 MHz) δ8.0(m, 2H), 7.1(m, 5H), 4.3(m, 1H), 3.2(m, 6H), 2.9(m, 1H), 2.5(m, 1H), 2.2(m, 8H), 1.8(m, 4H)
EXAMPLE 48
{1-[2-(4-Chloro-phenyl)-2-methoxy-ethyl]-piperidin-4-yl}-(4-fluoro-phenyl)-methanone
The procedure given in Example 34 was followed using 4-chlorostyrene oxide as a reactant, instead of 2-(4-nitro-phenyl)oxirane, to give {1-[2-(4-chloro-phenyl)-2-methoxy-ethyl]-piperidin-4-yl}-(4-fluoro-phenyl)-methanone.
1H-NMR (CDCl3, 200 MHz) δ8.0(m, 2H), 7.2(m, 6H), 4.3(m, 1H), 3.3(m, 5H), 2.9(m, 1H), 2.7(m, 1H), 2.4(m, 1H), 2.2(m, 2H), 1.9(m, 4H)
EXAMPLE 49
(4-Fluoro-phenyl)-[1-(2-methoxy-2-thiophen-2-yl-ethyl)-piperidin-4-yl]-methanone
The procedure given in Example 34 was followed using 2-thiophen-2-yl-oxirane as a reactant, instead of 2-(4-nitro-phenyl)oxirane, to give (4-fluoro-phenyl)-[1-(2-methoxy-2-thiophen-2-yl-ethyl)-piperidin-4-yl]-methanone.
1H-NMR (CDCl3, 200 MHz) δ8.0(m, 2H), 7.1(m, 5H), 4.6(m, 1H), 3.4(s, 3H), 3.0(m, 6H), 2.4(m, 2H), 1.8(m, 4H)
EXAMPLE 50
(4-Fluoro-phenyl)-{1-[2-methoxy-2-(4-trifluoromethyl-phenyl)-ethyl]-piperidin-4yl}-methanone
The procedure given in Example 34 was followed using 4-trifluoromethylstyrene oxide as a reactant, instead of 2-(4-nitro-phenyl)oxirane, to give (4-fluoro-phenyl)-{1-[2-methoxy-2-(4-trifluoromethyl-phenyl)-ethyl]-piperidin-4-yl}-methanone.
1H-NMR (CDCl3, 200 MHz) δ8.0(m, 2H), 7.6(m, 2H), 7.4(m, 2H), 7.1(m, 2H), 4.4(m, 1H), 3.3(s, 3H), 3.0(m, 2H), 2.9(m, 1H), 2.8(m, 1H), 2.5(m, 1H), 2.2(m, 2H), 1.8(m, 4H)
EXAMPLE 51
(4-Fluoro-phenyl)-{1-[2-methoxy-2-(4-methoxy-phenyl)-ethyl]-piperidin-4-yl}-methanone
The procedure given in Example 34 was followed using 4-methoxystyrene oxide as a reactant, instead of 2-(4-nitro-phenyl)oxirane, to give (4-fluoro-phenyl)-{1-[2-methoxy-2-(4-methoxy-phenyl)-ethyl]-piperidin-4-yl}-methanone.
1H-NMR (CDCl3, 200 MHz) δ8.0(m, 2H), 7.2(m, 4H), 6.8(m, 2H), 4.3(m, 1H), 3.8(s, 3H), 3.2(s, 3H), 3.1(m, 3H), 2.8(m, 1H), 2.5(m, 1H), 2.3(m, 2H), 1.8(m, 4H)
EXAMPLE 52
4-{2-[4-(4-Fluoro-benzoyl)-piperidin-1-yl]-1-methoxy-ethyl}-benzonitrile
The procedure given in Example 34 was followed using 4-oxiranyl-benzonitrile as a reactant, instead of 2-(4-nitro-phenyl)oxirane, to give 4-{2-[4-(4-fluoro-benzoyl)-piperidin-1-yl]-1-methoxy-ethyl}-benzonitrile.
1H-NMR (CDCl3, 200 MHz) δ8.0(m, 2H), 7.6(m, 2H), 7.4(m, 2H), 7.0(m, 2H), 4.4(m, 1H), 3.0(br, 8H), 2.4(br, 4H), 1.8(m, 3H)
EXAMPLE 53
(4-Fluoro-phenyl)-{1-[2-(4-methanesulfonyl-phenyl)-2-methoxy-ethyl]-piperidin-4yl}-methanone
The procedure given in Example 34 was followed using 2-(4-methanesulfonyl-phenyl)-oxirane as a reactant, instead of 2-(4-nitro-phenyl)oxirane, to give (4-fluoro-phenyl)-{1-[2-(4-methanesulfonyl-phenyl)-2-methoxy-ethyl]-piperidin-4-yl}-methanone.
1H-NMR (CDCl3, 200 MHz) δ8.0(m, 4H), 7.5(m, 2H), 7.1(m, 2H), 4.5(m, 1H), 3.4(s, 3H), 3.0(s, 3H), 2.8(m, 3H), 2.5(m, 1H), 2.3(m, 2H), 1.8(m, 4H)
EXAMPLE 54
(4-Fluoro-phenyl)-{1-[2-methoxy-2-(4-trifluoromethoxy-phenyl)-ethyl]-piperidin-4-yl}-methanone
The procedure given in Example 34 was followed using 2-(4-trifluoromethoxy-phenyl)-oxirane as a reactant, instead of 2-(4-nitro-phenyl)oxirane, to give (4-fluoro-phenyl)-{1-[2-methoxy-2-(4-trifluoromethoxy-phenyl)-ethyl]-piperidin-4-yl}-methanone.
1H-NMR (CDCl3, 200 MHz) δ8.0(m, 2H), 7.2(m, 61H), 4.4(m, 1H), 3.2(m, 7H), 2.8(m, 1H), 2.5(m, 1H), 2.3(m, 2H), 1.8(m, 4H)
EXAMPLE 55
(4-Fluoro-phenyl)-[1-(2-methoxy-2-pyridin-2-yl-ethyl)-piperidin-4-yl]-methanone
The procedure given in Example 34 was followed using 2-oxiranyl-pyridine as a reactant, instead of 2-(4-nitro-phenyl)oxirane, to give (4-fluoro-phenyl)-[1-(2-methoxy-2-pyridin-2-yl-ethyl)-piperidin-4-yl]-methanone.
1H-NMR (CDCl3, 200 MHz) δ8.4(m, 1H), 7.9(m, 2H), 7.6(m, 1H), 7.3(m, 1H), 7.0(m, 31H), 4.5(m, 1H), 3.0(m, 7H), 2.8(m, 21H), 2.1(m, 21H), 1.8(m, 4H)
EXAMPLE 56
(4-Fluoro-phenyl)-[1-(2-methoxy-2-quinolin-2-yl-ethyl)-piperidin-4-yl]-methanone
The procedure given in Example 34 was followed using 2-oxiranyl-quinoline as a reactant, instead of 2-(4-nitro-phenyl)oxirane, to give (4-fluoro-phenyl)-[1-(2-methoxy-2-quinolin-2-yl-ethyl)-piperidin-4-yl]-methanone.
1H-NMR (CDCl3, 200 MHz) δ8.2(m, 2H), 8.0(m, 2H), 7.8(m, 2H), 7.6(m, 2H), 7.1(m, 2H), 4.7(m, 1H), 3.4(s, 3H), 3.2(m, 3H), 2.9(m, 1H), 2.7(m, 1H), 2.3(m, 2H), 1.9(m, 4H)
EXAMPLE 57
(4-Chloro-phenyl)-{1-[2-methoxy-2-(4-nitro-phenyl)-ethyl]-piperidin-4-yl}-methanone
The procedure given in Example 34 was followed using 4-(4-chlorobenzoyl)piperidine as a reactant, instead of 4-(4-fluorobenzoyl)piperidine, to give (4-chloro-phenyl)-{1-[2-methoxy-2-(4-nitro-phenyl)-ethyl]-piperidin-4-yl}-methanone.
1H-NMR (CDCl3, 200 MHz) δ8.2(m, 2H), 7.8(m, 2H), 7.2(m, 4H), 4.4(m, 1H), 3.3(s, 3H), 3.1(m, 2H), 2.9(m, 1H), 2.8(m, 1H), 2.4(m, 1H), 2.2(m, 2H), 1.8(m, 4H)
EXAMPLE 58
{1-[2-Methoxy-2-(4nitro-phenyl)-ethyl]-piperidin-4-yl}-p-tolyl-methanone
The procedure given in Example 34 was followed using 4-(4-methylbenzoyl)piperidine as a reactant, instead of 4-(4-fluorobenzoyl)piperidine, to give {1-[2-methoxy-2-(4-nitro-phenyl)-ethyl]-piperidin-4-yl}-p-tolyl-methanone.
1H-NMR (CDCl3, 200 MHz) δ8.2(m, 2H), 7.8(m, 2H), 7.4(m, 2H), 7.2(m, 2H), 4.5(m, 1H), 3.3(s, 3H), 3.1(m, 2H), 2.9(m, 1H), 2.8(m, 1H), 2.6(m, 1H), 2.3(m, 2H), 1.8(m, 4H)
EXAMPLE 59
(4-Fluoro-phenyl)-[1-(2-ethoxy-3-phenoxy-propyl)-piperidin-4-yl]-methanone; hydrochloride
A mixture of 4-(4-fluorobenzoyl)piperidine (5mmol) and 1,2-epoxy-3-phenoxypropane (5 mmol) was refluxed in 30 ml of isopropanol for 4 h. This solution was then concentrated on a rotary evaporator and diluted with ethyl acetate. This mixture was then washed with brine, the resulting organic layer was dried and concentrated in vacuo. The crude product was dissolved in THF (50 ml) and was added with sodium hydride (2 eq.) at 0° C. The reaction mixture was stirred at room temperature for 10 min. This solution was followed by the addition of excess iodoethane (>3 eq.). After 1 hour stirring at 25° C., this solution is concentrated on a rotary evaporator and diluted with ethyl acetate. The organic layer was extracted 3 times with dichloromethane, dried and concentrated in vacuo. The residue was purified by column chromatography (ethyl acetate:hexane=1:1). The resulting (4-fluoro-phenyl)-[1-(2-ethoxy-3-phenoxy-propyl)-piperidin-4-yl]-methanone was dissolved in dichloromethane and the solution was treated with a solution of HCl in ethyl ether.
The resulting precipitate was filtered to give (4-fluoro-phenyl)-[1-(2-ethoxy-3-phenoxy-propyl)-piperidin-4-yl]-methanone; hydrochloride.
1H-NMR (CDCl3, 200 MHz) δ12.0(br, 1H), 8.0(m, 2H), 7.2(m, 4H), 6.8(m, 3H), 4.7(m, 2H), 4.2(m, 2H), 3.8(m, 4H), 3.3(m, 6H), 2.6(m, 3H), 2.2(m, 2H)
EXAMPLE 60
(4-Fluoro-phenyl)-[1-(2-methoxy-3-phenoxy-propyl)-piperidin-4-yl]-methanone
The procedure given in Example 59 was followed using iodomethane as a reactant, instead of iodoethane, to give (4-fluoro-phenyl)-[1-(2-methoxy-3-phenoxy-propyl)-piperidin-4-yl]-methanone.
1H-NMR (CDCl3, 200 MHz) δ8.0(m, 2H), 7.3(m, 2H), 7.1(m, 2H), 6.9(m, 3H), 4.2(m, 2H), 3.7(m, 1H), 3.5(m, 3H), 3.2(m, 1H), 3.0(m,2H), 2.6(m, 2H), 2.2(m, 2H), 1.8(m, 4H)
EXAMPLE 61
(S)-(4-Fluoro-phenyl)-[1-(2-methoxy-3-phenoxy-propyl)-piperidin-4-yl]-methanone
The procedure given in Example 59 was followed using (S)-1,2-epoxy-3-phenoxypropane and iodomethane as reactants, instead of 1,2-epoxy-3-phenoxypropane and iodoethane, to give (S)-(4-fluoro-phenyl)-[1-(2-methoxy-3-phenoxy-propyl)-piperidin-4-yl]-methanone.
1H-NMR (CDCl3, 200 MHz) δ8.0(m, 2H), 7.3(m, 2H), 7.1(m, 2H), 6.9(m, 3H), 4.2(m, 2H), 3.7(m, 1H), 3.5(m, 3H), 3.2(m, 1H), 3.0(m,2H), 2.6(m, 2H), 2.2(m, 2H), 1.8(m, 4H)
EXAMPLE 62
(R)-(4-Fluoro-phenyl)-[1-(2-methoxy-3-phenoxy-propyl)-piperidin-4-yl]-methanone
The procedure given in Example 59 was followed using (R)-1,2-epoxy-3-phenoxypropane and iodomethane as reactants, instead of 1,2-epoxy-3-phenoxypropane and iodoethane, to give (R)-(4-fluoro-phenyl)-[1-(2-methoxy-3-phenoxy-propyl)-piperidin-4-yl]-methanone.
1H-NMR (CDCl3, 200 MHz) δ8.0(m, 2H), 7.3(m, 2H), 7.1(m, 2H), 6.9(m, 3H), 4.2(m, 2H), 3.7(m, 1H), 3.5(m, 3H), 3.2(m, 1H), 3.0(m, 2H), 2.6(m, 2H), 2.2(m, 2H), 4H)
EXAMPLE 63
(4-Fluoro-phenyl)-[1-(2-methoxy-3-(4-chloro-phenoxy)-propyl)-piperidin-4-yl]-methanone
The procedure given in Example 59 was followed using 4-chlorophenyl glycidyl ether and iodomethane as reactants, instead of 1,2-epoxy-3-phenoxypropane and iodoethane, to give (4-fluoro-phenyl)-[1-(2-methoxy-3-(4-chloro-phenoxy)-propyl)-piperidin-4-yl]-methanone.
1H-NMR (CDCl3, 200 MHz) 8.2(m, 2H), 8.0(m, 2H), 7.5(m, 2H), 7.2(m, 2H), 4.5(m, 1H), 3.4(s, 3H), 3.2(m, 2H), 2.9(m, 1H), 2.8(m, 1H), 2.5(m, 1H), 2.3(m, 2H), 1.8(m, 4H)
EXAMPLE 64
(4-Fluoro-phenyl)-[1-(2-methoxy-3-(4-methoxy-phenoxy)-propyl)-piperidin-4-yl]-methanone
The procedure given in Example 59 was followed using glycidyl 4-methoxyphenyl ether and iodomethane as reactants, instead of 1,2-epoxy-3-phenoxypropane and iodoethane, to give (4-fluoro-phenyl)-[1-(2-methoxy-3-(4-methoxy-phenoxy)-propyl)-piperidin-4-yl]-methanone.
1H-NMR (CDCl3, 200 MHz) δ8.0(m, 2H), 7.2(m, 2H), 6.8(m, 4H), 4.0(m, 1H), 3.8(s, 3H), 3.7(m, 1H), 3.6(s, 3H), 3.0(m, 2H), 2.8(m, 3H), 2.2(m, 3H), 1.8(m, 4H)
EXAMPLE 65
(4-Fluoro-phenyl)-[1-(2-methoxy-3-(2-methyl-phenoxy)-propyl)-piperidin-4-yl]-methanone
The procedure given in Example 59 was followed using glycidyl 2-methylphenyl ether and iodomethane as reactants, instead of 1,2-epoxy-3-phenoxypropane and iodoethane, to give (4-fluoro-phenyl)-[1-(2-methoxy-3-(2-methyl-phenoxy)-propyl)-piperidin-4-yl]-methanone.
1H-NMR (CDCl3, 200 MHz) δ8.0(m, 2H), 7.2(m, 4H), 6.9(m, 2H), 4.1(m, 3H), 3.8(m, 2H), 3.5(m, 3H), 3.2(m, 1H), 3.0(m,2H), 2.6(m, 4H), 2.2(m, 1H), 1.8(m, 4H)
EXAMPLE 66
(4-Fluoro-phenyl)-[1-(2-methoxy-3-(4-tert-butyl-phenoxy)-propyl)-piperidin-4-yl]-methanone
The procedure given in Example 59 was followed using 4-tert-butylphenyl glycidyl ether and iodomethane as reactants, instead of 1,2-epoxy-3-phenoxypropane and iodoethane, to give (4-fluoro-phenyl)-[1-(2-methoxy-3-(4-tert-butyl-phenoxy)-propyl)-piperidin-4-yl]-methanone.
1H-NMR (CDCl3, 200 MHz) δ8.0(m, 2H), 7.3(m, 2H), 7.2(m, 2H), 6.9(m, 2H), 4.1(m, 3H), 3.8(m, 1H), 3.5(s, 3H), 3.1(m, 2H), 2.6(m, 2H), 2.3(m, 2H), 1.8(m, 4H), 1.3(m, 9H)
EXAMPLE 67
(4Fluoro-phenyl)-[1-(2-methoxy-3-(4-nitro-phenoxy)-propyl)-piperidin-4yl]-methanone
The procedure given in Example 59 was followed using 4-nitrophenyl glycidyl ether and iodomethane as reactants, instead of 1,2-epoxy-3-phenoxypropane and iodoethane, to give (4-fluoro-phenyl)-[1-(2-methoxy-3-(4-nitro-phenoxy)-propyl)-piperidin-4-yl]-methanone.
1H-NMR (CDCl3, 200 MHz) δ8.2(m, 2H), 8.0(m, 2H), 7.2(m, 4H), 4.2(m, 2H), 3.8(m, 1H), 3.5(s, 3H), 3.2(m, 1H), 3.0(m,2H), 2.6(m, 2H), 2.3(m, 2H), 1.8(m, 4H)
EXAMPLE 68
(4-Fluoro-phenyl)-[1-(2-propyloxy-3-phenoxy-propyl)-piperidin-4-yl]-methanone; hydrochloride
The procedure given in Example 59 was followed using iodopropane as a reactant, instead of iodoethane, to give (4-fluoro-phenyl)-[1-(2-propyloxy-3-phenoxy-propyl)-piperidin-4-yl]-methanone; hydrochloride.
1H-NMR (CDCl3, 200 MHz) δ12.4(br, 1H), 8.0(m, 2H), 7.3(m, 4H), 6.9(m, 3H), 4.7(m, 1H), 4.1(m, 3H), 3.7(m, 4H), 3.3(m, 4H), 2.8(m,2H), 2.1(m, 4H), 1.0(m, 3H)
EXAMPLE 69
(4-Fluoro-phenyl)-[1-(2-butoxy-3-phenoxy-propyl)-piperidin-4-yl]-methanone; hydrochloride
The procedure given in Example 59 was followed using iodobutane as a reactant, instead of iodoethane, to give (4-fluoro-phenyl)-[1-(2-butoxy-3-phenoxy-propyl)-piperidin-4-yl]-methanone; hydrochloride.
1H-NMR (CDCl3, 200 MHz) δ12.0(br, 1H) 8.0(m, 2H), 7.2(m, 4H), 6.9(m, 3H), 4.4(m, 1H), 4.0(m, 3H), 3.8(m, 4H), 3.3(m, 5H), 2.7(m,2H), 2.1(m, 2H), 1.4(m, 3H). 0.9(m, 3H)
EXAMPLE 70
(4-Fluoro-phenyl)-[1-(2-benzyloxy-3-phenoxy-propyl)-piperidin-4-yl]-methanone; hydrochloride
The procedure given in Example 59 was followed using benzyl bromide as a reactant, instead of iodoethane, to give (4-fluoro-phenyl)-[1-(2-benzyloxy-3-phenoxy-propyl)-piperidin-4-yl]-methanone; hydrochloride.
1H-NMR (CDCl3, 200 MHz) δ12.0(br, 1H) 8.0(m, 2H), 7.2(m, 8H), 6.9(m, 4H), 4.9(m, 3H), 4.5(m, 1H), 4.1(m, 3H), 3.3(m, 5H), 2.6(m, 2H), 2.2(m, 2H)
EXAMPLE 71
(4-Fluoro-phenyl)-{1-[2-(4-isopropyl-phenyl)-2-[1,2,4]triazoyl-1-yl-ethyl]-piperidin-4-yl}-methanone trihydrochloride
A mixture of 4-(4-fluorobenzoyl)piperidine (5 mmol) and 2-(4-isopropylphenyl)oxirane (5 mmol) was refluxed in 30 ml of isopropanol for 4 h. This solution was then concentrated on a rotary evaporator and diluted with ethyl acetate. This mixture was then washed with brine, the resulting organic layer was dried and concentrated in vacuo. The crude product was dissolved in dichloromethane (50 ml) and was added with methanesulfonyl chloride (2 eq.) and triethylamine (3 eq.) at 0° C. The reaction mixture was stirred at room temperature for 1 h. This solution was then added triethylamine (3 eq.), followed by the addition of excess 1,2,4-triazole (>3 eq.). After 4 hours stirring at room temperature, this solution was concentrated on a rotary evaporator and diluted with ethyl acetate. The organic layer was washed 2 times with saturated sodium bicarbonate solution, dried and concentrated in vacuo. The residue was purified by column chromatography (ethyl acetate:hexane=1:1). The resulting (4-fluoro-phenyl)-{1-[2-(4-isopropyl-phenyl)-2-[1,2,4]triazoyl-1-yl-ethyl]-piperidin-4-yl}-methanone was dissolved in dichloromethane and the solution was treated with a solution of HCl in ethyl ether. The resulting precipitate was filtered to give (4-fluoro-phenyl)-{1-[2-(4-isopropyl-phenyl)-2-[1,2,4]triazoyl-l -yl-ethyl]-piperidin-4-yl}-methanone trihydrochloride.
1H-NMR(DMSO-D6, 200 MHz), δ1.14(d,6H), 1.93(m,4H), 2.89(m,1H), 3.16(m,2H), 3.71(m,4H), 4.39(m,1H), 5.82(br,2H), 6.59(d,1H), 7.32(m,6H), 8.09(t,2H), 8.25(s,1H), 9.08(s,1H), 11.17(br,1H)
EXAMPLE 72
(4-Fluoro-phenyl)-[1-(2-phenyl-2-[1,2,4]triazol-1-yl-ethyl)-piperidin-4-yl]-methanone
The procedure given in Example 71 was followed using styrene oxide as a reactant, instead of 2-(4-isopropylphenyl)oxirane, to give (4-fluoro-phenyl)-[1-(2-phenyl-2-[1,2,4]triazoyl-1-yl-ethyl)-piperidin-4-yl]-methanone.
1H-NMR(CDCl 3 , 200 MHz), δ1.72(m,4H), 2.28(m,2H), 2.79(d,1H), 2.95(d,1H), 3.01(d,1H), 3.16(m,1H), 3.41(q,1H), 5.52(q,1H), 7.09(t,2H), 7.29(m,5H), 7.91(t,2H), 7.96(s,1H), 8.25(s,1H)
EXAMPLE 73
{1-[2-(3,4-Dimethyl-phenyl)-2-[1,2,4]triazol-1-yl-ethyl]-piperidin-4-yl}-(4-fluoro-phenyl)-methanone
The procedure given in Example 71 was followed using 3,4-dimethylstyrene oxide as a reactant, instead of 2-(4-isopropylphenyl)oxirane, to give {1-[2-(3,4-dimethyl-phenyl)-2-[1,2,4]triazoyl-1yl-ethyl]-piperidin-4-yl}-(4-fluoro-phenyl)-methanone
1H-NMR(CDCl 3 , 200 MHz), δ1.76(m,4H), 2.25(s,6H), 2.33(m,2H), 2.80(d,1H), 2.97(m,2H), 3.17(m,1H), 3.39(q,1H), 5.48(q,1H), 7.11(m,5H), 7.92(m,3H), 8.22(s,1H)
EXAMPLE 74
(4-Fluoro-phenyl)-[1-(4-phenyl-2-[1,2,4]triazoyl-1-yl-butyl)-piperidin-4-yl]-methanone
The procedure given in Example 71 was followed using 2-phenethyl-oxirane as a reactant, instead of 2-(4-isopropylphenyl)oxirane, to give (4-fluoro-phenyl)-[1-(4-phenyl-2-[1,2,4]triazoyl-1-yl-butyl)-piperidin-4-yl]-methanone.
1H-NMR(CDCl 3 , 200 MHz), δ1.74(m,4H), 2.18(m,2H), 2.32(m,2H), 2.54(m,2H), 2.71(t,1H), 2.87(m,1H), 3.12(m,1H), 3.57(m,2H), 4.27(m,1H), 7.21(m,7H), 7.92(m,4H),
EXAMPLE 75
{1-[2-(4-tert-Butyl-phenyl)-2-[1,2,4]triazol-1-yl-ethyl]-piperidin-4-yl}-(4-fluoro-phenyl)-methanone
The procedure given in Example 71 was followed using 4-tert-butylstyrene oxide as a reactant, instead of 2-(4-isopropylphenyl)oxirane, to give {1-[2-(4-tert-butyl-phenyl)-2-[1,2,4]triazol-1-yl-ethyl]-piperidin-4-yl}-(4-fluoro-phenyl)-methanone.
1H-NMR(CDCl 3 , 200 MHz), δ1.27(s,9H), 2.73(m,4H), 2.25(m,2H), 2.77(d,1H), 2.97(m,2H), 3.14(m,1H), 3.39(q,1H), 5.49(q,1H), 7.09(t,2H), 7.29(q,4H), 7.94(m,3H), 8.21(s,1H)
EXAMPLE 76
{1-[2-(2-Chloro-phenyl)-2-[1,2,4]triazol-1-yl-ethyl]-piperidin-4-yl}-(4-fluoro-phenyl)-methanone
The procedure given in Example 71 was followed using 2-chlorostyrene oxide as a reactant, instead of 2-(4-isopropylphenyl)oxirane, to give {1-[2-(2-chloro-phenyl)-2-[1,2,4]triazol-1-yl-ethyl)-piperidin-4-yl}-(4-fluoro-phenyl)-methanone.
1H-NMR(CDCl 3 , 200 MHz), δ1.73(m,4H), 2.31(m,2H), 2.80(d,1H), 2.95(q,1H), 3.09(m,2H), 3.39(q,1H), 6.05(q,1H), 7.09(t,2H), 7.26(m,2H), 7.37(m,2H), 7.89(q,2H), 7.95(s,1H), 8.27(s,1H)
EXAMPLE 77
(4-Fluoro-phenyl)-{1-[2-(4-nitro-phenyl)-2-[1,2,4]triazol-1-yl-ethyl]-piperidin-4-yl}yl-methanone
The procedure given in Example 71 was followed using 4-nitrostyrene oxide as a reactant, instead of 2-(4-isopropylphenyl)oxirane, to give (4-fluoro-phenyl)-{1-[2-(4-nitro-phenyl)-2-[1,2,4]triazol-1-yl-ethyl]-piperidin-4-yl}-methanone.
1H-NMR(CDCl 3 , 200 MHz), δ1.74(m,4H), 2.31(q,2H), 2.81(d,1H), 2.93(m,1H), 3.11(m,2H), 3.36(q,1H), 5.59(m,1H), 7.12(t,2H), 7.49(d,2H), 7.92(m,3H), 819(m,2H), 8.29(s, 1H)
EXAMPLE 78
(4-Fluoro-phenyl)-[1-(2-naphthalen-2-yl-2-[1,2,4]triazol-1-yl-ethyl]-piperidin-4-yl]-methanone
The procedure given in Example 71 was followed using 2-naphthalene oxide as a reactant, instead of 2-(4-isopropylphenyl)oxirane, to give (4-fluoro-phenyl)-[1-(2-naphthalen-2-yl-2-[1,2,4]triazol-1-yl-ethyl)-piperidin-4-yl]-methanone.
1H-NMR(CDCl 3 , 200 MHz), δ1.79(m,4H), 2.33(m,2H), 2.85(d,1H), 3.10(m,3H), 3.57(m,1H), 5.73(m,1H), 7.12(t,2H), 7.49(m,3H), 7.85(m,7H), 8.29(s, 1H)
EXAMPLE 79
(4-Fluoro-phenyl)-{1-[2-[1,2,4]triazol-1-yl-2-(4-trifluoromethyl-phenyl)-ethyl]-piperidin-4-yl}-methanone
The procedure given in Example 71 was followed using 4-trifluoromethylstyrene oxide as a reactant, instead of 2-(4-isopropylphenyl)oxirane, to give (4-fluoro-phenyl)-{1-[2-[1,2,4]triazol-1-yl-2-(4-trifluoromethyl-phenyl)-ethyl]-piperidin-4-yl}-methanone.
1H-NMR(CDCl 3 , 200 MHz), δ1.76(m,4H), 2.37(m,2H), 2.81(d,1H), 3.01(m,2H), 3.19(m,1H), 3.39(m,1H), 5.59(m,1H), 7.13(,2H), 7.43(d,2H), 7.63(d,2H), 7.91(m,3H), 8.29(s,1H)
EXAMPLE 80
(4-Fluoro-phenyl)-[1-(2-phenyl-2-tetrazol-1-yl-ethyl)-piperidin-4-yl]-methanone
The procedure given in Example 71 was followed using styrene oxide and tetrazole as reactants, instead of 2-(4-isopropylphenyl)oxirane and 1,2,4-triazole, to give (4-fluoro-phenyl)-[1-(2-phenyl-2-tetrazol-1-yl-ethyl)-piperidin-4-yl]-methanone.
1H-NMR(CDCl 3 , 200 MHz), δ1.75(m,4H), 2.31(m,2H), 2.79(d,1H), 3.03(m,2H), 3.18(m,1H), 3.42(q,1H), 5.79(q,1H), 7.07(t,2H), 7.38(m,5H), 7.92(t,2H), 8.79(s, 1H)
EXAMPLE 81
(4-Fluoro-phenyl)-[1-(2-phenyl-2-[1,2,3]triazol-1-yl-ethyl)-piperidin-4-yl]-methanone
The procedure given in Example 71 was followed using styrene oxide and 1,2,3-triazole as reactants, instead of 2-(4-isopropylphenyl)oxirane and 1,2,4-triazole, to give (4-fluoro-phenyl)-[1-(2-phenyl-2-[1,2,3]triazol-1-yl-ethyl)-piperidin-4-yl]-methanone.
1H-NMR(CDCl 3 , 200 MHz), δ1.69(m,4H), 2.27(m,2H), 2.91(q,2H), 3.13(m,2H), 3.47(m,1H), 5.79(q, 1H), 7.07(t,2H), 7.25(m,5H), 7.63(d,2H), 7.91(t,2H)
EXAMPLE 82
(4-Fluoro-phenyl)-[1-(2-imidazol-1-yl-2-phenyl-ethyl)-piperidin-4-yl]-methanone
The procedure given in Example 71 was followed using styrene oxide and imidazole as reactants, instead of 2-(4-isopropylphenyl)oxirane and 1,2,4-triazole, to give (4-fluoro-phenyl)-[1-(2-imidazol-1-yl-2-phenyl-ethyl)-piperidin-4-yl]-methanone.
1H-NMR(CDCl 3 , 200 MHz), δ1.79(m,4H), 2.22(m,2H), 2.79(d,1H), 2.99(m,2H), 3.11(m,2H), 5.29(m,1H), 7.05(m,6H), 7.29(m,3H), 7.63(s,1H), 7.93(m,2H)
EXAMPLE 83
Carbonic acid 1-(4-ethyl-phenyl)-2-[4-(4-fluoro-benzoyl)-piperidin-1-yl]-ethyl ester methyl ester
A mixture of 4-(4-fluorobenzoyl)piperidine (5 mmol) and 2-(4-ethylphenyl)-oxirane (5 mmol) was refluxed in 30 ml of isopropanol for 4 h. This solution was then concentrated on a rotary evaporator and diluted with ethyl acetate. This mixture was then washed with brine, the resulting organic layer was dried and concentrated in vacuo. The crude product was dissolved in THF (50 ml) and was added with 1,1′-carbonyl diimidazole (2 mmol) at 0° C. The reaction mixture was stirred at room temperature for 4 h, followed by the addition of excess methanol (10 ml) at 0° C. After 5 h stirring at room temperature, water was added to terminate the reaction. The organic layer was extracted 3 times with dichloromethane, dried and concentrated in vacuo. The resulting carbonic acid 1-(4-ethyl-phenyl)-2-[4-(4-fluoro-benzoyl)-piperidin-1-yl]-ethyl ester methyl ester was obtained by column chromatography.
1H-NMR (CDCl3, 200 MHz) δ7.9(m, 2H), 7.2(m, 6H), 5.8(m, 1H), 3.8(s, 3H), 3.0(m, 4H), 2.6(m, 3H), 2.2(m, 2H), 1.8(m, 4H), 1.2(m, 3H)
EXAMPLE 84
Carbonic acid 2-[4-(4-fluoro-benzoyl)-piperidin-1-yl]-1-phenyl-ethyl ester methyl ester
The procedure given in Example 83 was followed using styrene oxide as a reactant, instead of 2-(4-ethylphenyl)-oxirane, to give carbonic acid 2-[4-(4-fluoro-benzoyl)-piperidin-1-yl]-1-phenyl-ethyl ester methyl ester.
1H-NMR (CDCl3, 200 MHz) δ8.0(m, 2H), 7.3(m, 5H), 7.1(m, 2H), 5.9(m, 1H), 3.8(s, 3H), 3.0(m, 4H), 2.6(dd 1H), 2.3(m, 2H), 1.8(m, 4H)
EXAMPLE 85
Carbonic acid ethyl ester 2-[4-(4-fluoro-benzoyl)-piperidin-1-yl]-1-phenyl-ethyl ester
The procedure given in Example 83 was followed using styrene oxide and ethanol as reactants, instead of 2-(4-ethylphenyl)-oxirane and methanol, to give carbonic acid ethyl ester 2-[4-(4-fluoro-benzoyl)-piperidin-1-yl]-1-phenyl-ethyl ester.
1H-NMR (CDCl3, 200 MHz) δ8.0(m, 2H), 7.3(m, 5H), 7.1(m, 2H), 5.9(m, 1H), 4.2(m, 2H), 3.0(m, 4H), 2.6(dd 1H), 2.3(m, 2H), 1.8(m, 4H), 1.3(m, 3H)
EXAMPLE 86
Carbonic acid 2-[4-(4-fluoro-benzoyl)-piperidin-1-yl]-1-phenyl-ethyl ester propyl ester
The procedure given in Example 83 was followed using styrene oxide and propanol as reactants, instead of 2-(4-ethylphenyl)-oxirane and methanol, to give carbonic acid 2-[4-(4-fluoro-benzoyl)-piperidin-1-yl]-1-phenyl-ethyl ester propyl ester.
1H-NMR (CDCl3, 200 MHz) δ7.9(m, 2H), 7.3(m, 5H), 7.1(m, 2H), 5.8(m, 1H), 4.1(m, 2H), 3.0(m, 4H), 2.6(dd, 1H), 2.2(m, 2H), 1.8(m, 6H), 1.0(m, 3H)
EXAMPLE 87
Carbonic acid 2-[4-(4-fluoro-benzoyl)-piperidin-1-yl]-1-phenyl-ethyl ester isopropyl ester
The procedure given in Example 83 was followed using styrene oxide and isopropanol as reactants, instead of 2-(4-ethylphenyl)-oxirane and methanol, to give carbonic acid 2-[4-(4-fluoro-benzoyl)-piperidin-1-yl]-1-phenyl-ethyl ester isopropyl ester.
1H-NMR (CDCl3, 200 MHz) δ8.0(m, 2H), 7.3(m, 5H), 7.1(m, 2H), 5.8(m, 1H), 4.8(m, 1H), 3.0(m, 4H), 2.6(m, 1H), 2.2(m, 2H), 1.8(m, 4H), 1.3(m, 6H)
EXAMPLE 88
Carbonic acid 2-[4-(4-fluoro-benzoyl)-piperidin-1-yl]-1-phenyl-ethyl ester phenyl ester
The procedure given in Example 83 was followed using styrene oxide and phenol as a reactant, instead of 2-(4-ethylphenyl)-oxirane and methanol, to give carbonic acid 2-[4-(4-fluoro-benzoyl)-piperidin-1-yl]-1-phenyl-ethyl ester phenyl ester.
1H-NMR (CDCl3, 200 MHz) δ8.0(m, 2H), 7.4(m, 7H), 7.2(m, 5H), 5.9(m, 1H), 3.1(m, 4H), 2.7(dd, 1H), 2.3(m, 2H), 1.8(m, 4H)
EXAMPLE 89
Carbonic acid benzyl ester 2-[4-(4-fluoro-benzoyl)-piperidin-1-yl]-1-phenyl-ethyl ester
The procedure given in Example 83 was followed using styrene oxide and benzyl alcohol as reactants, instead of 2-(4-ethylphenyl)-oxirane and methanol, to give carbonic acid benzyl ester 2-[4-(4-fluoro-benzoyl)-piperidin-1-yl]-1-phenyl-ethyl ester.
1H-NMR (CDCl3, 200 MHz) δ8.0(m, 2H), 7.4(m, 10H), 7.1(m, 2H), 5.8(m, 1H), 5.2(m, 2H), 3,0(m, 4H), 2.6(dd, 1H), 2.2(m, 2H), 1.8(m, 4H)
EXAMPLE 90
Carbonic acid 1-[4-(4-fluoro-benzoyl)-piperidin-1-ylmethyl]-3-phenyl-propyl ester methyl ester
The procedure given in Example 83 was followed using 2-phenethyl-oxirane as a reactant, instead of 2-(4-ethylphenyl)-oxirane, to give carbonic acid 1-[4-(4-fluoro-benzoyl)-piperidin-1-ylmethyl]-3-phenyl-propyl ester methyl ester.
1H-NMR (CDCl3, 200 MHz) δ8.0(m, 2H), 7.2(m, 7H), 4.9(m, 1H), 3.8(s, 3H), 3.0(m, 3H), 2.6(m, 4H), 2.2(m, 2H), 2.0(m, 2H), 1.8(m, 4H)
EXAMPLE 91
Carbonic acid 1-(3-chloro-phenyl)-2-[4-(4-fluoro-benzoyl)-piperidin-1-yl]-ethyl ester isopropyl ester
The procedure given in Example 83 was followed using 3-chlorostyrene oxide and isopropanol as reactants, instead of 2-(4-ethylphenyl)-oxirane and methanol, to give carbonic acid 1-(3-chloro-phenyl)-2-[4-(4-fluoro-benzoyl)-piperidin-1-yl]-ethyl ester isopropyl ester.
1H-NMR (CDCl3, 200 MHz) δ8.0(m, 2H), 7.3(m, 4H), 7.1(m, 2H), 5.8(m, 1H), 4.9(m, 1H), 3.0(m, 4H), 2.6(dd, 1H), 2.2(m, 2H), 1.8(m, 4H), 1.3(m, 6H)
EXAMPLE 92
Carbonic acid 1-(4-chloro-phenyl)-2-[4-(4-fluoro-benzoyl)-piperidin-1-yl]-ethyl ester isopropyl ester
The procedure given in Example 83 was followed using 4-chlorostyrene oxide and isopropanol as reactants, instead of 2-(4-ethylphenyl)-oxirane and methanol, to give carbonic acid 1-(4-chloro-phenyl)-2-[4-(4-fluoro-benzoyl)-piperidin-1-yl]-ethyl ester isopropyl ester.
1H-NMR (CDCl3, 200 MHz) δ8.0(m, 2H), 7.3(m, 5H), 7.1(m, 2H), 5.8(m, 1H), 4.9(m, 1H), 3.0(m, 4H), 2.6(dd, 1H), 2.2(m, 2H), 1.8(m, 4H), 1.3(m, 6H)
EXAMPLE 93
Carbonic acid 1-(4-cyano-phenyl)-2-[4-(4-fluoro-benzoyl)-piperidin-1-yl]-ethyl ester isopropyl ester
The procedure given in Example 83 was followed using 4-oxiranyl-benzonitrile and isopropanol as reactants, instead of 2-(4-ethylphenyl)-oxirane and methanol, to give carbonic acid 1-(4-cyano-phenyl)-2-[4-(4-fluoro-benzoyl)-piperidin-1-yl]-ethyl ester isopropyl ester.
1H-NMR (CDCl3, 200 MHz) δ8.0(m, 2H), 7.7(d, 2H), 7.5(d, 2H), 7.1(m, 2H), 5.8(m, 1H), 4.9(m, 1H), 3.0(m, 4H),2.6(dd 1H), 2.2(m, 2H), 1.8(m, 4H), 1.3(m, 6H)
EXAMPLE 94
Carbonic acid 2-[4-(3-chloro-benzoyl)-piperidin-1-yl]-1-phenoxymethyl-ethyl ester isopropyl ester
The procedure given in Example 83 was followed using styrene oxide and isopropanol as reactants, instead of 2-(4-ethylphenyl)-oxirane and methanol, to give carbonic acid 2-[4-(3-chloro-benzoyl)-piperidin-1-yl]-1-phenoxymethyl-ethyl ester isopropyl ester.
1H-NMR (CDCl3, 200 MHz) δ7.8(m, 2H), 7.3(m, 4H), 6.9(m, 3H), 5.1(m, 1H), 4.9(m, 1H), 4.1(m, 2H), 3.1(m, 1H), 3.0(m, 2H), 2.7(m, 2H), 2.2(m, 2H), 1.8(m, 4H), 6H) | Provided herein are racemic or enantiomerically enriched benzoyl piperidine compounds and pharmaceutically useful salts thereof, pharmaceutical compositions comprising an effective amount of racemic or enantiomerically enriched benzoyl piperidine compounds to treat central nervous system diseases and methods of treating central nervous system diseases in a mammal, in particular psychoses and cognition disorders. | 2 |
This application claims the benefit of U.S. Provisional No. 60/061,541 filed Oct. 7, 1997.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to hopped malt beverages, especially alcoholic brewery beverages produced at least in part from malt, and to improvements in the flavor stability thereof. More particularly, the present invention relates to imparting to hopped malt beverages improved stability against the production of thiols associated with a “skunky” odor and flavor development in beer that has been exposed to visible light.
2. Description of Related Art
As is well known and accepted in the malt beverage brewing art, subjecting a hopped malt brewery beverage, especially an alcoholic hopped malt brewery beverage such as lager, ale, porter, stout, and the like (herein generically referred to as “beer”), to sunlight or artificial light causes a significantly deleterious effect on the sensory qualities of the beverage by generating a so-called “skunky” flavor, which is sometimes also referred to as “sunstruck” or “light struck” flavor. It is known that the skunky flavor is the result of photochemical changes in the beverage that produce volatile sulfur-containing compounds. These sulfur compounds are thought to be formed at least in part by the reaction of other sulfur-containing compounds with photochemically degraded hop components in the beverage. Only very small amounts of these sulfur compounds are required to be present to impart the skunky flavor to the beverage and render it unacceptable.
The photochemical reaction is assisted by the presence of riboflavin, one of several photo-sensitizers in the beverage. The riboflavin emanates mainly from the malt, and to a minor extent via the hops, used in the production of beer and, according to common wisdom, action of yeast during the fermentation. (See Tamer et al. Enzyme Microb Technology 10:754-56, December 1988.) This photochemical reaction is a problem that to some degree has been the subject of a diverse remediation.
An approach that relies on primary packaging coloration either to exclude light or, at least, exclude those wavelengths of light that are particularly problematic, has been widely adopted. Such attempts to prevent beverages from becoming skunky involve enclosing the beer in cans or bottles made of protective, i.e., colored, glass, brown or amber being most efficient (see U.S. Pat. No. 2,452,968). These bottles reduce or eliminate the transmission to the beverage of light of wavelength shorter than about 560 nanometers. Such light is most harmful because it assists the riboflavin in enhancing the production of the undesirable volatile sulfur compounds.
Brown bottle glass has become a standard for the brewing industry for the purpose of avoiding the formation of skunky off-flavors, although in some circumstances green glass can be employed, generally with reduced efficacy.
Flint, or clear, glass—apart from the exclusion of the preponderance of ultraviolet wavelengths—is ineffective as packaging for traditional beer products that are susceptible to the formation of skunky off-flavors on exposure to visible wavelengths. In order to enjoy the visual aesthetic that is associated with this type of primary packaging (for example, the variously red, golden, or brown coloration and clarity of the beer beverage), the brewer is faced with the option of employing reduced hop extracts or taking the risk of the formation of skunky flavor. The skunky off-flavor, as previously stated, is, problematic. The use of reduced hop extracts, on the other hand, does not deliver the “noble” hop essences to the beverage that are associated with traditional beer products.
Another method developed to address the problem of “skunky” flavor production uses reduced isohumulones in place of hops or hop extracts. (See Verzele, M., et al., U. Inst. Brew. 73:255-57, 1967.)
Other methods involve adding light-stabilizing materials to the beverage. (See U.S. Pat. No. 4,389,421.) However, in some jurisdictions, the use of such compounds has not been approved. Further, many brewers are reluctant to use any additives at all but, rather, use hops or hop extracts in an effort to achieve traditional beer flavor.
Another alternative has been suggested by U.S. Pat. No. 4,389,421. This patent describes malt beverages that have added organic compounds possessing a 1,8-epoxy group and, optionally, another compound with a 1,4-epoxy group. The amount of the 1,8-epoxy compound is at least 0.25 ppb and, preferably, about one to six ppb by weight. Suitable sources of the 1,8-epoxy compounds are taught as including 1,8-cineole, or plant essences from cardamom, eucalyptus, peppermint, lavender, laurel, or star anise. A suitable 1,4-epoxy compound is 1,4-cineole. The addition of these compounds is taught as preventing the development of the “light struck” flavor in a range of malt beverages (for example, beer, ale, malt liquors, etc.).
The problem of skunky flavor has been the subject of research for many years, and such research continues. (See Sakuma et al., “Sunstruck Flavor Formation in Beer,” American Society of Brewing Chemists, Inc., 162-65, 1991). This article also deals with the part believed to be played by riboflavin in the reaction that produces the “skunky” flavor and suggests that removing riboflavin from the finished beer may solve the problem. However, an acceptable means for achieving that suggestion has not been readily apparent, and the problem persists.
In accordance with currently accepted brewing science, the compound that is thought to be primarily responsible for this skunky off-flavor is 3-methyl-2-butene-1-thiol. The compound is believed to be formed when photochemical cleavage of side chains of hop-derived isohumulones is followed by the reaction of the resulting 3-methyl-2-butenyl radical with an undetermined sulfur-containing compound that is normally present in beer. Riboflavin, which is contributed from both vegetable and, to a much lesser extent, yeast sources, is generally accepted as being a photochemical sensitizer in this reaction sequence.
SUMMARY OF THE INVENTION
In accordance with the present invention, it has been found, in the production of a hopped malt beverage, that if riboflavin is substantially absent or present in only a relatively small or “insignificant” amount in a process liquid, then the resulting beverage has enhanced stability against light and less tendency to produce skunky off-flavors.
Wort produced in the usual manner from malt(s) typically has a relatively high riboflavin content (for example, about 0.4 ppm or more). As used herein, riboflavin contents above 0.2 ppm are defined as “high.” In accordance with the present invention, the riboflavin content is reduced to less than 0.2 ppm, that level being defined for use herein as an “insignificant” amount.
The present invention provides a process for the production of a hopped malt beverage comprising hopping a process liquid with a high riboflavin content and treating the process liquid with an effective amount of an absorbent clay to absorb the riboflavin. The riboflavin content is reduced to less than about 0.2 ppm, and the resulting hopped malt beverage has enhanced stability to light.
In another aspect, the present invention relates to a hopped malt beverage with enhanced light stability prepared by a process comprising treating a process liquid having a high riboflavin content with an effective amount of an absorbent clay to absorb the riboflavin. The riboflavin content is reduced to less than about 0.2 ppm, resulting in a hopped malt beverage with enhanced stability to light.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In the process of the present invention, an absorbent clay is added to the process liquid of a brewing process to absorb, and thereby remove, riboflavin present in the process liquid.
As employed herein, the term “process liquid” means any unhopped wort, fermented wort (including green or bright beer), or finished beer produced using malt.
Riboflavin is a photo-sensitizer for the photochemical cleavage of side chains of the isohumulones that are also present in the process liquid to yield 3-methyl-2-butenyl radicals that react with a sulfur-containing compound in the brew to produce thiols, for example, 3-methyl-2-butene-1-thiol, which have a skunky aroma. In the absence of the riboflavin initiator, the rate of photochemical reaction is significantly reduced, and the light stability of the product is thereby improved.
The present invention has special application to the production of a beer having enhanced stability to light. This stability can lead to an extended shelf life of 25 percent or more than is typical for regular, untreated beer in situations where incident light causes deterioration of the product.
In a preferred embodiment of the invention, an improved process is provided for the production of a beer in which process a process liquid having a high riboflavin content is hopped to produce the desired beverage, wherein the improvement comprises treating the process liquid with an effective amount of a clay absorbent, whereby the riboflavin content in the process liquid is reduced to less than 0.2 ppm, and the resulting beer has enhanced stability to light.
It is believed that reducing the amount of riboflavin to a relatively low level prior to hopping inhibits the formation of sulfur compounds imparting a “skunky” flavor and, hence, is responsible for the enhanced light stability. Moreover, it has also been found that if, as in one embodiment of the present invention, the amount of riboflavin is reduced prior to the fermentation stage of the brewing process (for example, in the unhopped wort), the same beneficial result is achieved.
It is preferred that at least 90 percent, more preferably 95 percent, and most preferably substantially all, of the riboflavin be removed from the process liquid either prior to or after hopping, although reductions in excess of as little as 50 percent can be useful. In practice, this means the process liquid, if it is wort, may have a maximum riboflavin content of less than about 0.2 ppm, preferably less than about 0.1 ppm, and more preferably less than about 0.05 ppm after treatment. It also means that the process liquid, if it is a fermented liquid, may have a maximum riboflavin content of less than about 0.15 ppm, preferably less than about 0.1 ppm, more preferably less than about 0.07 ppm, and most preferably less than about 0.03 ppm after treatment.
The desired hopped malt beverage can be produced using generally well-known brewing procedures adapted, where necessary, to incorporate the required riboflavin reduction stage, preferably by the absorption treatment of the present invention at an appropriate stage. Consequently, an all-malt or a malt-plus-adjunct combination can be used as a starting substrate, as desired.
Beer not treated by the process of the present invention which has been bottled in clear flint glass, green glass, and the like, and subjected to strong light, for example, sunlight or artificial light indoors, can develop an unacceptable skunky flavor within minutes, often as fast as 20 minutes. The skunky flavor is readily discernible by experienced taste panelists who routinely make quality control evaluations in beer products. Such panels have descried that beverages treated by the process of the present invention do not develop the same degree of skunky flavor for about 16 hours and, in fact, may not do so for as long as 20 to 30 hours or more.
Generally, hops or hop pellets are used to ensure that the “traditional” beer taste is obtained. Although there is a small amount of riboflavin in hops and hop pellets, it is insignificant as taught herein. However, even that small riboflavin content could be removed if desired. Moreover, hop extracts can be substituted for the hops or hop pellets. Such extracts do not contain any riboflavin and, hence, can be used to advantage in the present invention.
Additionally, the yeast pitched to commence fermentation may include some small amount of riboflavin, but, again, this amount should not be sufficient to affect the present invention adversely. However, it is advantageous to use a yeast that is substantially free of riboflavin or at least is riboflavin-deficient.
The clay employed as the absorbent in the practice of the present invention will be a hydrated aluminum silicate or a hydrated aluminum-magnesium silicate. Examples of such clays that can be used include Fuller's earth, bentonite, kaolinite, illite, and halloysite, as well as mixtures thereof.
Fuller's earth is a porous colloidal aluminum silicate clay having as a chief ingredient attapulgite, a hydrated aluminum-magnesium silicate of the general structure (MgAl) 5 Si 8 O 22 (OH) 4 ·4H 2 O.
Bentonite is a colloidal aluminum silicate clay composed chiefly of montmorillonite, of which there are two varieties: Na bentonite, which has a high swelling capacity in water, and Ca bentonite, which has a negligible swelling capacity. The general structure of montmorillonite is Al 2 O 3 ·4SiO 2 ·H 2 O.
Preferably the clay is attapulgite, montmorillonite, or mixtures thereof.
The clay is added to the process liquid in an amount effective to absorb all, or at least a majority, of the riboflavin present in the liquid. The actual concentration employed will be dependent upon a number of factors, including the chemical and physical, for example, porosity, characteristics of the particular clay chosen. The actual amount required in a given case can be readily determined by a person of ordinary skill in the art without undue experimentation. Generally, the amount will lie in the range of from about 0.1 to about 60, and preferably from about 1 to about 30.
The process of the present invention can be used in any known commercial brewing process, including both batch and continuous processes. It can also be used in combination with other means for reducing riboflavin content, such as the means described in U.S. Pat. No. 5,582,857, incorporated herein by reference.
The advantages and the important features of the present invention will be more apparent from the following example.
EXAMPLE
A concentrated lager beer was brewed from a 16° Plato wort. Veegum™ clay (R. T. Vanderbilt) is a complex magnesium aluminum silicate that forms a colloidal thixotropic gell on hydration. Various amounts of this clay were added to the dilution water that was subsequently used to dilute the high gravity brew to the desired end-product concentration. The addition was facilitated by bubbling CO 2 through the water/clay dispersion for about thirty minutes.
The concentrated lager was then diluted with the water/hydrated clay diluent, and the mixture was allowed to rest (i.e., with the beer in contact with the hydrated clay absorbent) for 30 to 60 minutes. Thereafter, the clay was filtered off, and the beer was packaged in clear flint bottles.
The packaged beer was then exposed to light for twenty-four hours in a light chamber, assessed by a trained taste panel, and analyzed for riboflavin concentration. The riboflavin concentration was measured using HPLC techniques, employing a Spectrophysics SP100LC and C 18 reversed phase column. The detection system employed a Waters Scanning Fluorescence Spectrophotometer.
The trained taste panel rated the beer on a scale of 1 through 10, in which the highest score, 10, was representative of an intense light struck flavor, while a score of 1 represented an absence of perceptible light struck flavor development. The panel results were averaged, and both the panel tasting and riboflavin analyses were carried out for light-exposed and unexposed control beers, as well as beers treated in accordance with the present invention to levels of Veegum clay of 30 and 5 grams per liter, respectively. The results are set out in Table 1.
TABLE 1
Clay
Average Taste
Exposure Time
Riboflavin
Beer (Lager)
Concentration
Panel Score
(Hours)
Concentration
Control
0 g/l
1
0
0.266
Unexposed
Control
0 g/l
7.8
24
0.266
Exposed
Treated
30 g/l
1
24
0
Exposed
Treated
5 g/l
1
24
0.024
Exposed
At the clay treatment levels set out in this Example, no skunky off-flavors were detected by the panel for either of the two treated beers, even though nine percent of the native riboflavin was left in the beer that had only been treated with five g/l of clay absorbent.
The invention has been described in detail with particular reference to preferred embodiments thereof, but it is understood that variations and modifications can be effected within the spirit and scope of the invention. | A process for reducing the propensity of riboflavin-containing malt beverages employs the treatment of beer or its intermediates with Fuller's earth absorbents and, in particular, colloidal magnesium aluminum silicates, especially attapulgite and montmorillonite clays. This process effects absorbance of riboflavin contained in such beer or its intermediates and can be shown to improve the stability of a treated beer against the formation of skunky off-flavors following exposure to visible wavelengths of light. | 2 |
CROSS REFERENCE TO RELATED APPLICATIONS
This application claims priority to U.S. provisional patent application Ser. No. 60/548,772, filed Feb. 27, 2004, of common title and inventorship, the entire contents which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention pertains generally to animal husbandry, and more particularly to feeding racks. In a more specific manifestation, the invention pertains to a mobile rack optimally configured for feeding large and powerful animals such as bison and the like.
2. Description of the Related Art
Animal husbandry is a very old technology, certainly prior to any general written histories. Throughout the ages mankind has derived much benefit from animals, ranging from companionship and security from the trusted dog to sources of food and materials when in need. While pre-historic man is thought to have been a hunter and gatherer, reliance upon random events of nature has not been accepted by mankind. Instead, man has developed ways to keep and care for animals which provides synergistic benefit to both man and animal. This is referred to as animal husbandry, which is simply caring for the needs of animals.
While the field of animal husbandry is very broad, and pertains to many diverse species of animals, the present invention is much more directed to the care, and more particularly to the feeding, of very large and powerful animals. In the United States, prior to the European settlers, there were vast herds of bison that roamed the central plains. These animals are ideally adapted to the diverse and sometimes extreme climate, and are able to forage from grasses and other plants that grow naturally. However, these animals are very large and powerful, and have needs and requirements that are somewhat different from cattle. With the influx of Europeans, the bison was almost entirely replaced by cattle, many species which were imported from Europe. The techniques for caring for cattle were well understood by the Europeans, and the cattle were often thought to be more refined and bred.
Relatively recently, there has been a renewed interest in bison. People have learned that the natural processes which led to the selection of bison in the central United States were as a direct result of the suitability of the species for the environment. Furthermore, research of late has revealed that the products of bison, such as the meat, provide generally unexpected benefit to the health and well being of mankind. Furthermore, there is a large and growing consumer base which considers bison meat to be preferable to the meat derived from cattle.
With this renewed interest has come a desire to provide better care for these animals. However, these creatures are much different from most species of cattle. Bison have very powerful front shoulders, and are commonly larger and more powerful than cattle. Consequently, equipment as basic as feeders that are used for cattle may not be suitable for use with bison. In fact, ordinary cattle feeders are all too frequently damaged or destroyed when used with bison.
Exemplary of the prior art feeders is Monin, who in U.S. Pat. No. 5,496,145 incorporated herein by reference for the teachings of feeders, illustrates a feeder having a generally cylindrical support configuration. This shape permits bales of any geometry to be loaded into the feeder from above. The bales will then drop, under the force of gravity, to the cylindrical supports below, where they are accessible by hungry animals. This arrangement provides relatively simple and only minimal handling by a ranch hand, while preserving the feed. Without some type of holder, the bales will directly contact the ground, where it is well known that they will spoil at an undesirably high rate. Unfortunately, with rigid supports the powerful bison are liable to destroy the feeder. While it may seem intuitive to simply strengthen the feeder itself, such as by manufacture from relatively heavier materials, this in turn leads to undesirable harm to the bison. Something has to give, whether it is the feeder or the bison.
Another U.S. Pat. No. 5,586,519 to Wilkinson incorporated herein by reference, illustrates an outer frame and flexible chains forming curved supports. This design provides greater flexibility and permits an animal to access the feeder without harm to either animal or feeder. However, the chains are less than optimal in the available movement. Motion within the feeder, such as an accidental bump from loading equipment, while the bales are being loaded or even during feeding, may result in the chains moving unevenly and may in turn result in the feed passing between the chains and from the feeder. Additional documents exemplary of the art and incorporated herein by reference include U.S. Pat. No. 5,076,752 by Rader and U.S. Pat. No. 4,067,298 by Jones et al.
SUMMARY OF THE INVENTION
In a first manifestation, the invention is a mobile feeder. Within the mobile feeder, a mobile base has a longitudinal axis and a plurality of wheels displaced relative thereto and including both front and rear wheels. A base framework extends between the plurality of wheels. A longitudinally directed frame member extends from front wheels to rear wheels and maintains proper orientation therebetween. A tongue is additionally provided that is suitable for enabling a connection to various tow vehicles. The mobile feeder additionally has a feeder supported upon the mobile base that has an upper framing which circumscribes an open top, a feeder base, and side framing members extending between upper framing and feeder base. Attachment members couple feeder to mobile base. A low and generally central longitudinally directed framing member extends longitudinally between attachment members. A plurality of straps extend generally from adjacent upper framing down therefrom and underneath the low and generally central longitudinally directed framing member in an arcuate fashion. Resilient attachments couple the straps to upper framing, and links couple and space the straps to adjacent straps.
In a second manifestation, the invention is an animal feeder having a framework; at least two arcuately shaped straps repeating along a first general axis and being more flexible transverse to the first axis than parallel thereto; attachments suspending the straps from the framework and permitting relative movement therebetween; and a base which supports the framework.
In a third manifestation, the invention is, in combination, a mobile base and a feeder defining a mobile feeder. The mobile base has a longitudinal axis, a plurality of wheels displaced relative to the longitudinal axis and includes a pair of front wheels and a pair of rear wheels, at least one base framework extending between the plurality of wheels, and a longitudinally directed frame member which extends between front and rear wheels and maintains proper orientation therebetween. A tongue suitable for enabling a connection to various tow vehicles is coupled to the pair of front wheels to re-orient them when the tongue is moved relative to the longitudinally directed frame member. The feeder is supported upon the mobile base, and has an upper framing which circumscribes an open top; a feeder base; side framing members extending between upper framing and feeder base; attachment members coupling feeder base to mobile base; a plurality of straps extending from a first terminus adjacent to the upper framing to a second terminus adjacent the upper framing member in an arcuate fashion; resilient attachments coupling the plurality of straps to upper framing; and links coupling and spacing the plurality of straps.
OBJECTS OF THE INVENTION
Exemplary embodiments of the present invention solve inadequacies of the prior art by providing a feeder having easily filled arcuate supports and resilient mounts attaching the supports to the frame. Trays may be provided which are supported upon the frame and which collect any feed that may escape beneath the supports.
A first object of the invention is to provide a durable feeder which will not harm large animals. A second object of the invention is to optimally preserve feed. Another object of the present invention is to ensure that the feeder is readily loaded with one or a plurality of bales of feed, while requiring minimal skill or caution during loading. A further object of the invention is to enable the feeder to be transported across both short and long distances, whether empty or full, and, if so desired, be separated from the mobile transport base. Yet another object of the present invention is to provide the foregoing objects using ready manufacturing materials and techniques. An additional object of the invention is to couple the components to permit replacement in the field, and to reduce the number of unique components, thereby simplifying repair where necessary.
BRIEF DESCRIPTION OF THE DRAWINGS
The foregoing and other objects, advantages, and novel features of the present invention can be understood and appreciated by reference to the following detailed description of the invention, taken in conjunction with the accompanying drawings, in which:
FIG. 1 illustrates a preferred embodiment mobile feeder designed in accord with the teachings of the present invention from a front plan view.
FIG. 2 illustrates the preferred embodiment mobile feeder of FIG. 1 from a rear projected view.
FIG. 3 illustrates the preferred embodiment mobile feeder of FIG. 2 in further combination with a preferred feed tray.
DESCRIPTION OF THE PREFERRED EMBODIMENT
In a most preferred embodiment designed in accord with the teachings of the invention and illustrated in FIGS. 1–2 , a mobile feeder 1 includes a mobile base 2 and a feeder 10 supported thereon. In this preferred embodiment, mobile base 2 may be a wheel set of the type typically used as the base for traditional hay wagons or the like found on many farms, though any suitable mobile base may be used in association with the present invention. Such a mobile base 2 will typically include a plurality of wheels 3 , four in the preferred embodiment, and at least one base framework 4 which may, as illustrated, extend between wheels 3 . While not essential to the workings of the invention, it will be understood that most such wagons will typically have a longitudinally directed frame member, such as member 6 visible in FIG. 2 , which extends from the front wheel set to the back and maintains the two in proper orientation. A tongue 5 enables connection of mobile base 2 to various tow vehicles, as will be described herein below. This tongue 5 may further be coupled to the front wheel set to permit the re-orientation of front wheels 3 when tongue 5 is moved relative to member 6 . In such case, a certain amount of steering is intrinsically provided within the front wheel set, to better enable mobile feeder 1 to track behind a towing vehicle.
Feeder 10 includes an upper framing 11 which circumscribes an open top. Side framing members 12 are provided about feeder 10 . In the preferred embodiment mobile feeder 1 , these side framing members 12 are located at each corner, and are also found adjacent longitudinally directed frame member 6 at the front and rear of feeder 10 . Attachment members 13 are preferably provided which permit feeder 10 to be firmly attached to mobile base 2 . In the preferred embodiment, attachment members 13 are in the form of rectangular frames at the front and rear lowermost portions of feeder 10 , which in turn also permits feeder 10 to be independently placed upon the ground and be self-supporting separate from mobile base 2 . The particular shape and geometry of attachment members 13 are not believed to be critical to the operation of the present invention, and so they may take on any shape or geometry that fulfills the intended functions of attachment and support. In the preferred embodiment, attachment members 13 include posts that slip into standard pockets found on many prior art wagon frames.
Extending longitudinally between attachment members 13 is a low and generally central longitudinally directed framing member 14 . As may be recognized, the use of square or round tubing, or even members of other geometry such as I-beams or any other suitable framing will be understood to be included herein for consideration of fabrication of the various members which comprise mobile feeder 1 , including framing member 14 .
Extending generally from adjacent upper framing 11 down therefrom and most preferably underneath framing member 14 in an arcuate fashion are a number of straps 15 . Straps 15 are most preferably semi-rigid, and will maintain their arcuate shape under the load that would be induced by feed. These straps 15 are most preferably held onto upper framing 11 by a plurality of flexible and resilient attachments 16 . In the preferred embodiment, these attachments 16 may be of a reasonably tough and durable elastomer such as a rubber compound or the like, and may for exemplary purposes be filled with various compounds and ingredients including carbon black, various cross-linking and vulcanizing agents, plasticizers, and other compounds which may be deemed to be suitable for the present application. Other elastomeric or resilient materials or attachments, the materials, geometries and compositions which will be recognized as being of infinite variation and so too many to attempt to list individually herein, may be utilized to form the present coupling. However, regardless of specific material or geometry utilized, these attachments 16 should provided a significant amount of resilience and strength to protect both animal and feeder.
Linking and spacing the various straps 15 is a link 17 . In this first preferred embodiment, this link 17 may be relatively rigid and may, for exemplary purposes only and not limited thereto, comprise a steel strap or the like. However, as will be apparent, other materials may be used for link 17 , even those which are flaccid, provided adequate design considerations are made. The attachment between straps 15 , resilient attachments 16 , and links 17 is most visible in FIGS. 2 and 3 , which illustrates the flexible support loops comprising resilient attachments 16 and bar comprising link 17 utilized in the preferred embodiment of FIG. 1 from a projected view. As may be identified therein, fasteners may be provided which couple each of the components together. While bolts and nuts or rivets may be used, any of the myriad of equivalents may also be used, and the particular fastener selected is not consequential to the operation of the invention. Consequently, the particular means or device used for fastening will be chosen by a designer reasonably skilled in the art, with consideration of the present disclosure. Nevertheless, it is preferred to use fasteners throughout the preferred embodiment mobile feeder 1 that are removeable using basic tools, which permits any components that become damaged during use to readily be removed and replaced. In mobile feeder 1 , bolts and nuts have been used to attach many of the feeder 10 framing components to each other, so that, for exemplary purposes, if a longitudinally extending upper framing member 11 becomes bent, this framing member may be unbolted from the remaining framing members and replaced, without requiring destructive cutting or the like.
By coupling straps 15 and resilient attachments 16 together, any forces that may be applied on one strap 15 will not only be coupled through a single adjacent resilient attachment 16 but will most preferably also be coupled through several nearby resilient attachments 16 through the action of link 17 . Link 17 additionally provides a relatively consistent spacing between straps 15 , even during or after significant or forceful use. Most preferably, this spacing will be at least at an average as wide as would minimally be required for one or more species of animals for which the present invention is adapted for to reasonably feed therefrom. In the preferred embodiment, the spacing is sufficiently large to permit bison or buffalo to feed therefrom. The straps 15 should also be sufficiently close together to avoid substantial quantities of hay or other feed for which the present invention may be designed from passing between adjacent straps before, during or after such feeding.
As is known, steel straps such as are used in the preferred embodiment feeder 10 have a rectangular cross-section which causes them to be substantially more rigid and resistant to bending movement parallel to the longitudinal axis of the rectangular cross-section than orthogonal thereto. In the present application, this means that straps 15 are generally more resistant to bending movement that would displace them along the longitudinal axis of mobile base 2 than they are to bending movements that would cause them to move laterally with respect to base 2 . The result of this different bending resistance is quite significant in operation. As may be appreciated, the relative stiffness along the longitudinal axis of mobile base 2 further helps to ensure that the desired spacing between straps 15 , suitable for animals to feed while not permitting feed to pass through, is maintained. However, when an animal charges forward, or tries to force deeper into feeder 10 to access food, straps 15 will most preferably be sufficiently pliant to absorb such forces without unduly stressing the balance of mobile feeder 1 or harming the animal. In such event, it will be recognized that the affected straps 15 may deform from the ordinary smooth arcuate geometry, and a certain amount of resilience within resilient attachments 16 will permit this flexure without concentrating stress at the terminations of straps 15 .
As should be recognized then, straps 15 are preferably designed to be rigid along the longitudinal axis of feeder 10 , to maintain relatively even spacing and consequently preserve feed. However, they should be pliant and resilient transverse to the longitudinal axis of feeder 10 , to permit limited deformation and shock absorption such as might occur when being impacted by a charging or forceful feeding animal pursuing food. The materials chosen for straps 15 and resilient attachments 16 will be considered in association with the anticipated forces applied by the particular animal for which the feeder is designed, to best select the particular dimensions which will achieve this desired differential flexure. As should now be recognized, while steel straps having a simple rectangular cross-section are used in the preferred embodiment, materials other than steel may be used and shapes other than rectangular may be crafted by those skilled in the art that will still achieve the intended differential flexure. Many different materials and geometries will be contemplated by those skilled in the art in light of the present disclosure, but steel strap is readily available for low cost and is readily utilized in the manufacture of feeder 10 .
Preferred embodiment mobile feeder 1 is designed for optimal operation in further combination with animal feed such as hay or the like, though any type of feed may be transported in feeder 10 , so long as there is sufficient integrity within the feed to be reasonably retained within straps 15 . Most preferably, mobile feeder 1 will support a plurality of standard units of feed, such as a plurality of bails. As may be understood from the pliant operation of resilient attachments 16 and straps 15 , when the hay, other feed, animal, transport motion or other effector applies uneven forces, straps 15 may move slightly relative to one another from consistent or even spaces. Consequently, the feed transported therein must not only be able to span the average spacing, but some distance greater.
At first blush, the benefit of the flexible and resilient character of straps 15 and attachments 16 may not be apparent. However, when a bison feeds from feeder 10 , the bison may apply very large forces to straps 15 in pursuit of feed 18 . These animals are large, and capable of destroying even very heavily built feeders of conventional design. The preferred resilient attachment taught herein permits relatively lighter materials to be used, and at the same time provides better benefit not only in durability but also in animal care, since the structure provides resilience which reduces potential harm to the animals.
The preferred embodiment mobile feeder 1 is most preferably configured for the further combination with both animal feed and a towing vehicle, as will be apparent to those reasonably skilled in the art. An all-terrain vehicle, commonly known of as a four-wheeler or ATV, may be used as the towing vehicle, but it will be understood that other vehicles such as pick-up trucks, tractors, and any of a myriad of other vehicles may be used. An ATV vehicle is described purely for illustrative purposes and is in no way limiting the type of towing vehicle which may be used herein.
The mobility illustrated herein permits mobile feeder 1 to be used in a rotational feeding and grazing program. By moving mobile feeder 1 on a regular basis, the animals will also move about a pasture with the feeder. As is known, manure tends to be concentrated adjacent the feeder, and any grasses or crop will likewise be trampled. However, by periodically moving mobile feeder 1 about the pasture, the manure will be naturally distributed by the animals. Furthermore, any single locale will only have to endure minimal trampling, and will normally readily recover therefrom. With this natural distribution of manure, which helps to keep the soil fertile, and the prevention of destructive trampling, the entire pasture may be easily maintained in optimal condition by this simple movement of mobile feeder 1 .
FIG. 3 illustrates the preferred embodiment mobile feeder 1 of FIGS. 1 and 2 , and further illustrating feeder 10 in combination with feed trays 20 . These feed trays 20 will most preferably rest underneath straps 15 and generally central longitudinally directed framing member 14 . In the preferred embodiment illustrated therein, feed trays 20 will slope from a high point adjacent member 14 to a point lower farther therefrom. Such slope will assist in the delivery of any feed which inadvertently falls between straps 15 to feeding animals, without the feed contacting the ground and potentially being ruined. Most preferably, feed trays 20 will include a lip or edge 22 which helps to maintain any stray feed therein. In the illustrated embodiment, feed trays 20 may be attached using U-bolts at suitable anchor points, but any suitable method of attachment may be utilized. One significant benefit of bolts or similar removable fasteners is the ability to remove or replace trays 20 as desired or required. While not separately illustrated, it will be apparent that drain holes may be strategically located within feed trays 20 , to prevent an accumulation of liquid therein.
From these figures and foregoing description, several additional features and options may become more apparent. First of all, mobile feeder 1 may be manufactured from a variety of materials, including metals, resins and plastics, ceramics or cementitious materials, rubbers, elastomers, or even combinations of the above. The specific material used may vary, though special benefits are attainable if several important factors are taken into consideration. Firstly, mobile feeder 1 should be sufficiently durable to withstand the impact of any animals which may access feeder 10 . Preferably, feeder 10 will readily separate from mobile base 2 . Most preferably, mobile feeder 1 will also be weather and sunlight resistant and sufficiently durable to withstand the particular climate for the intended application, including any forces that may be applied that could tend to fracture or shear any of the components therein.
A variety of designs have been contemplated for mobile feeder 1 . The basic geometry illustrated herein is most preferred, and makes construction possible using readily available components and without difficult manufacture. However, mobile feeder 1 may also be manufactured to take on any suitable aesthetic appearance or geometry, or to take a form which offers other or additional functional benefit without departing from the spirit of the present invention. Various creature, fantasy or human figures, plants, and even unique thematic displays may be constructed. The materials used for a particular design may be chosen not only based upon the aforementioned factors such as weather resistance and structural soundness, but may also factor in the particular design.
While the foregoing details what is felt to be the preferred and additional alternative embodiments of the invention, no material limitations to the scope of the claimed invention are intended. The variants that would be possible from a reading of the present disclosure are too many in number for individual listings herein, though they are understood to be included in the present invention. Further, features and design alternatives that would be obvious to one of ordinary skill in the art are considered to be incorporated also. The scope of the invention is set forth and particularly described in the claims herein below. | A mobile feeder uses a wagon wheel set with a draw bar. The wheel set serves as the undercarriage for the feeder. The feeder has a plurality of arcuate supports that are spaced sufficiently to allow livestock to feed between. The arcuate supports are resiliently hung from a frame that defines the outer dimensions of the feeder and pass under a central, longitudinally extending frame bar. When impacted from an animal feeding transverse to the feeder, the arcuate supports flex resiliently, while still retaining proper spacing for both feed and animal. Resilient attachments couple the arcuate supports to frame, and links couple adjacent arcuate supports and thereby distribute forces and help to maintain spacing. Feed trays are provided beneath the arcuate supports to catch and retain any feed inadvertently escaping from the arcuate supports. The feed trays are most preferably sloped from the longitudinal center down and away from the longitudinal center, to provide gravity assist in delivering the errant feed to feeding animals. | 0 |
TECHNICAL FIELD
[0001] The present invention relates to a carriage for transporting a load, preferably a pallet, along a rail pair in a so-called deep racking store, comprising carrier means which, in a deactivated transport position of the carriage, are disposed to pass under a load resting on the rail pair and which, in an activated lifting position, are disposed to carry from beneath the load free from the rail pair, the carriage having a supporting chassis/frame provided with at least four wheels.
BACKGROUND ART
[0002] In so-called deep racking stores, use is made of pairs of rails for supporting stored loads which as a rule rest on pallets. Each rail pair is of considerable length so that a plurality of pallets may be disposed along a rail pair.
[0003] In a deep racking store, use is often made of a plurality of rail pairs above one another up to such a height which is accessible to a fork-lift truck or other lifting device. In addition, use is often made of a plurality of vertical stacks of rail pairs in side-by-side relationship so that the rail pairs form a grid pattern of both considerable height and width where each rail pair displays, as was mentioned above, considerable length.
[0004] For transporting pallets along a rail pair, use is made of a carriage which rolls on the rail pair and is designed in such a manner that, in a deactivated position, it may pass under loads resting on the rail pair. If, on the other hand, it is transferred to an activated lifting position, it lifts from beneath a load resting on the rail pair so that the load is free of the rail pair and can, with the aid of the carriage, be transported along the rail pair.
[0005] It will readily be perceived that a pallet lifted up by, for example, a fork-lift truck and placed at an end region of a rail pair may readily be transported with the aid of the carriage to the inner end of the rail pair. The carriage may thereafter return to the outer end of the rail pair to fill the rail pair with additional loads until the complete rail pair is fully loaded.
[0006] As a rule, one and the same carriage is employed for transporting loads on different rail pairs, for which reason the carriage is moved from one rail pair to another as required.
[0007] In order to lift the load, the carriage has a lifting device with at least so great a lifting distance that the carriage, with the lifting device in a deactivated position, may pass under a load resting on the rail pair while, in an activated lifting position, it lifts the load so high that it is free of the rail pair.
[0008] In a prior art carriage of the type described by way of introduction, the lifting device comprises a parallelogram or pantograph mechanism which, in the vertical direction, acts on carrier means disposed on the carriage so that these may be raised and lowered in relation to the carriage. The pantograph mechanism has an upper arm pivotally connected to the carrier means and a lower arm pivotally connected to the chassis or frame of the carriage, the arms also being interconnected to one another and, at this connecting point, further connected to a linear prime mover. Both of the arms are pivotal under the action of the prime mover between a position where they lie approximately in line with one another and where the carrier means are raised, and a position where the arms make an angle with one another and where the carrier means are lowered so that the carriage can pass under a load resting on a rail pair.
[0009] The above-described pantograph mechanism functions satisfactorily, but has insufficient load carrying capacity.
[0010] Constructions are also previously known in the art where the wheels of the carriage are adjustable in the vertical direction so that the entire carriage is raised and lowered in relation to the rail pair when the load is to be lifted up or deposited on a rail pair.
PROBLEM STRUCTURE
[0011] The present invention has for its object to design the carriage intimated by way of introduction such that this will display considerably greater lifting capacity than prior art carriages are capable of performing. Further, the present invention has for its object to design the carriage so that it will be simple and economical in manufacture, at the same time as needing but simple maintenance and possessing long service life.
SOLUTION
[0012] The objects forming the basis of the present invention will be attained if the carriage intimated by way of introduction is characterised in that the carrier means are rigidly connected to the chassis, that each wheel is journalled in an associated arm which is pivotally journalled in the chassis for raising and lowering the wheel in relation to the chassis, the arm being further operable by means of an operating device.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
[0013] The present invention will now be described in greater detail hereinbelow, with reference to the accompanying Drawings. In the accompanying Drawings:
[0014] FIG. 1 shows a carriage according to the present invention resting on a rail pair, a part of the one rail having been cut away for purposes of clarity and the carriage being in a deactivated transport position, i.e. in a lowered position;
[0015] FIG. 2 shows the carriage according to FIG. 1 in an activated lifting position, i.e. in a raised position;
[0016] FIG. 3 in a view corresponding to FIG. 1 is a vertical cross section through the carriage;
[0017] FIG. 4 in a view corresponding to FIG. 2 is a vertical cross section through the carriage; and
[0018] FIG. 5 shows a mounting unit included in the carriage with two wheels mounted thereon.
DESCRIPTION OF PREFERRED EMBODIMENT
[0019] FIGS. 1 and 2 show a rail 1 included in a rail pair in a deep racking store, the rail having, along its upper defining edge, a substantially horizontal support surface 2 which is intended for carrying a load, preferably a pallet. The support surface 2 is, in FIGS. 1 and 2 , at right angles to the plane of the Drawing and extends towards the observer from this plane.
[0020] The rail 1 further has a running surface 3 which is also horizontal and preferably parallel with the support surface 2 and is intended for supporting a carriage 4 according to the present invention. The support surface 2 and the running surface 3 are connected to one another by the intermediary of a wall 5 extending in the vertical direction of the rail, and further a downwardly directed flange 6 which extends downwards from that edge of the running surface 3 which is turned to face towards the other rail included in a rail pair.
[0021] In a rail pair, the two running surfaces 3 lie as horizontal shelves in between both of the walls 5 in the rail pair, while the support surfaces 2 extend away from one another from the upper edge portions of the walls 5 .
[0022] It will be apparent from FIGS. 1 and 2 that the carriage 4 has wheels 7 which are rotary with wheel axles 8 . In the right sides of both Figures, the wheels have been removed for purposes of clarity and it will be apparent that the axles 8 are carried by and rotary in bearings 9 , in the illustrated embodiment roller bearings.
[0023] On its upper side, the carriage 4 has carrier means 10 which are fixedly secured in the carriage and are thus rigidly connected to a chassis/frame included in the carriage. The carrier means 10 are disposed to engage from beneath with a load resting on a rail pair and lift the load so high that the load is free of the support surfaces 2 of the rail pair when the carriage 4 with the load is to be run along a rail pair. When the carriage 4 is to be run along the rail pair without a load, the carrier means 10 are located on a lower level, so low that the carriage 4 may freely pass under a pallet resting on the rail pair.
[0024] In FIG. 1 , the carriage is in a deactivated transport position, i.e. the lowered position, while in FIG. 2 , the carriage is in an activated lifting position, i.e. the raised position, and it will be apparent on a comparison between these two Figures that the wheel 7 and the axle 8 in FIG. 1 are of considerably higher vertical extent in relation to the carriage than is the case in FIG. 2 . From this it follows that the whole carriage 4 is raisable and lowerable for raising and lowering of the carrier means 10 by a corresponding lowering and raising of the wheels 7 , respectively. For raising and lowering the wheels in relation to the carriage and in particular its chassis and carrier means 10 , use is made of an operating device disposed in the carriage which, in turn, is connected to a prime mover. The operating device will be described in greater detail below.
[0025] It will be apparent from FIGS. 3 and 4 that the wheels 7 are each journalled via their axles 8 in their associated arm 11 , both of the arms illustrated in FIGS. 3 and 4 each having an outer portion 12 and an inner portion 13 . The two arms 11 are journalled in their central regions with journalling devices 14 with pivot shafts 15 in relation to the supporting chassis of the carriage.
[0026] For operating the wheels 7 and their axles 8 in the vertical direction, the carriage has an operating device 16 which is disposed for pivoting both of the arms 11 about the pivot shafts 15 . The operating device 16 includes an excenter or crank device which engages with the inner ends of the inner portions 13 of the arms 11 .
[0027] The operating device 16 has a drive shaft 17 which, for its rotation, is connected to a prime mover (not shown on the Drawings), for example an electric motor.
[0028] The wheels 7 of the carriage extend in the lateral direction outside the chassis or supporting frame of the carriage so that this be located in between the two downwardly directed flanges 6 on the rails included in a rail pair (see FIG. 1 ). In order to journal the axles 8 as close to the wheels as possible, the outer arm portions 12 are located a greater distance from the longitudinal centre line of the carriage than is the case for the inner arm portions 13 . Between these arm portions, connecting members or sleeves 18 are provided which mutually rigidly connect the two arm portions and which are included in the journal devices 14 of the arms.
[0029] Between the insides of the wheels 7 and the roller bearings included in the bearings 9 of the wheels, there are provided spacer sleeves which surround the wheel axles. The roller bearings in the bearings 9 are axially fixed in the outer arm portions 12 of the arms so that axial loadings on the wheels are transferred to these arm portions via the spacer sleeves and the roller bearings. In order to avoid flexural movements in the outer portions 12 of the arms, these are provided with guides whose purpose is to prevent axial movement of the wheel and the outer portions 12 of the arms in relation to the chassis of the carriage by transferring thereto the above-mentioned loadings. The guides include elongate apertures 19 in the outer portions 12 of the arms, the apertures being concentric about the pivot shafts 15 of the arms and being disposed at the outer ends of the outer arm portions 12 in particular outside the wheel axles 8 . As is apparent from FIGS. 3 and 4 , stub shafts extend through these apertures 19 which, at their ends facing towards the observer of FIGS. 3 and 4 , have heads or washers 20 which prevent movement towards the observer of FIGS. 3 and 4 of the outer end portions of the arms 11 . In such instance, the fixing of the outer portions 12 of the arms takes place in the longitudinal direction of the wheel axles 8 in that the stub shafts with the heads 20 are fixed in the chassis of the carriage. On the rear side (in FIGS. 3 and 4 ) of the arms, these abut against sliding guides which are rigidly connected to the chassis.
[0030] It should be mentioned that the wheels 7 pairwise have a common and through-going axle 8 whereby the wheels are interconnected to each other in the axial direction, so that, in principle, both of the guides for the outer portions 12 of the arms will thereby share an axial loading on the wheels. It should also be mentioned that the wheel axles 8 are parallel with the pivot shafts 15 of both arms 11 .
[0031] It will be apparent from FIG. 5 that, on each side of the carriage, the arms 11 and the operating device 16 disposed there are mounted in a mounting unit 21 which, in its turn, is secured in the chassis of the carriage. The mounting unit 21 has two outer or first walls 22 which are at right angles to the pivot shafts 15 of the arms 11 , as well as two inner or second walls 23 which are parallel with the outer walls 22 and which are located a distance inside them. The distance between the outer and inner walls is such that the sleeves 18 which the connect the outer portions 12 of the arms 11 with the inner portions 13 , as well as the arms proper, will have space without axial play between the mutually facing sides of these walls. The journals of the arms 11 are supported by the above-mentioned first and second walls 22 and 23 .
[0032] It will further be apparent from FIG. 5 that the two inner walls 23 in the mounting unit 21 are interconnected int. al. by the intermediary of an additional inner or third wall 24 . This wall 24 supports a bearing 25 for the drive shaft 17 and is therefore at right angles to both the drive shaft 17 , the pivot shafts 15 and the wheel axles 8 .
[0033] As was mentioned above, the operating device 16 includes an excenter 26 which is radially offset in relation to the drive shaft 17 ( FIGS. 3 and 4 ). On the excenter, there are disposed two roller bearings side-by-side, i.e. closely joined together in the axial direction. In FIGS. 3 and 4 , only the roller bearing most proximal to the observer of the Figure is visible.
[0034] The two roller bearings supported by the excenter 26 each have an inner ring 27 and an outer ring 28 . The outer ring on the roller bearing located most proximal in FIGS. 3 and 4 is accommodated in an aperture in the inner portion 13 of the left arm in the Figures, while the roller bearing located most distal from the observer of the Figure has its outer ring accommodated in a corresponding aperture in the inner portion 13 of the right arm 11 in the Figures, whose inner portion 13 in the Figures is located behind the inner portion of the left arm. In the vertical direction, the apertures in the inner portion 13 of the arms are of approximately the same extent as the diameter of the outer rings of the two roller bearings, so that the outer rings may be accommodated substantially without play in the apertures in the vertical direction. On the other hand, in the horizontal direction the apertures are of greater extent so that rotation of the excenter 26 a complete revolution may be put into effect without the outer rings of the bearings coming to contact with the left and right defining surfaces in the apertures in FIGS. 3 and 4 .
[0035] The operating device 16 has an upper and lower dead point, the arms 11 in the lower dead point of the operating device having their outer portions 12 raised, while the opposite applies when the operating device 16 is located in the upper dead point. As a result, the major advantage will be afforded that loadings on the wheels in the vertical direction will not be transferred to the prime mover that drives the operating device 16 when the carriage is located in its activated lifting position and in its deactivated transport position, in other words the operating device is “self-locking” when the wheels 7 are located in their maximum raised and maximum lowered positions in relation to the chassis.
[0036] In the foregoing, the bearings 9 of the wheels 7 have been described as roller bearings. Possibly, other types of bearings could be employed, for example bearings with different types of bushings. The same circumstance applies to the bearings for the drive shaft 17 and the bearings between the excenter 26 and the apertures of the arms 11 . Possibly, one variation could be conceivable where both of the roller bearings on the excenter 26 are replaced by a bearing whose outer ring engages with the apertures in the two arms 11 . | A carriage for transport of a load, for example a load pallet, along a rail pair in a so-called deep racking store, has a carrier arrangement which, in a deactivated transport position, passes under a load resting on the rail pair. The carrier arrangement is disposed, in an activated lifting position, to carry the load from beneath so that it is free of the rail pair. The carriage has a supporting frame or chassis provided with at least four wheels. The carrier arrangement is rigidly connected to the frame or chassis and each wheel is journalled in an associated arm. The arm is pivotally journalled in the frame so as to be able to raise and lower the wheel in relation to the frame. The am is operated by an operating device. | 1 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an electrode for water electrolysis and for a process for producing the same.
2. Description of the Prior Art
Electrodes, as well as processes for their manufacture, are particularly known from the technology developed for fuel cells, as for example from Berger, Carl, "Handbook of Fuel Cell Technology", pages 401-406, (Prentiss-Hall 1968) and Liebhafsky, H. A., and Cairns, E. J., "Fuel Cells and Fuel Batteries", pages 289-294 (John Wiley & Sons, 1968). The demand for an exactly defined reaction zone however requires a multiple-layer design and special treatment processes for such fuel cell electrodes.
The aforementioned electrodes are too complex in the design and too complicated and expensive in their production methods for water electrolysis. This fact applies particularly to production methods for large industrial plants involved in the economic production of hydrogen.
Electrodes for water electrolysis cells have been proposed, as for example in U.S. Pat. No. 4,039,409. These are mostly doped with catalysts, to accelerate the electro-chemical reactions.
The described electrodes have drawbacks with respect to their mechanical and chemical characteristics and the same is true with respect to those with applied catalysts.
A need therefore continues to exist for an electrode useful in water electrolysis which is not too complex in design, which is useful for the large industrial production of hydrogen and which has superior mechanical and chemical characteristics.
SUMMARY OF THE INVENTION
It is therefore an object of the invention to provide an electrode for water electrolysis.
Another object of the invention is to provide an electrode for water electrolysis which has good mechanical and chemical characteristics.
A further object of the invention is to provide an electrode for water electrolysis useful for the large scale production of hydrogen.
Still another object of the invention is to provide a process for preparing an electrode.
These and other objects of the invention which will more readily become apparent hereinafter have been attained by providing:
an electrode for water electrolysis which comprises a solid solution of graphite and polytetrafluorethylene impregnated with a catalyst mixture of platinum metal oxides, the solid solution being pressed and sintered on a reinforcing net of metal cloth.
Another object of the invention has been attained by providing a process for preparing the aforementioned electrode which comprises: mixing graphite and polytetrafluorethylene powders, pressing the mixture on a net of fine metal cloth, sintering the pressed mixture under an argon atmosphere at 340°-400° C., i.ersing said sintered mixture into an alcoholic solution of platinum metal chlorides, drying the resulting mixture, and oxidizing the mixture in air at 340°- 400° C.
BRIEF DESCRIPTION OF THE DRAWINGS
A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:
FIG. 1 is a cross-section of an electrode of the present invention and wherein a porous mass comprising graphite 1 and polytetrafluorethylene 2 is pressed on a net of metal cloth 3, which for the anode side is preferably Ta and Ti, and for the cathode side is preferably Ni, brass, bronze or any other copper alloy.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
This invention is based on an electrode for water electrolysis which has a good conductivity and good permeability for water and gas, has a long life as well as the property of accelerating the water electrolysis reaction in an optimum manner through catalytic effects.
It has proven to be advantageous to use a porous, permeable solid solution on a graphite basis as the material for the electrode and impregnating the same with a mixture of platinum-metal oxides as the catalyst. For these purposes, ruthenium oxide and iridium oxide are particularly preferred, favorably either alone, in mixtures with each other or with an additional platinum metal oxide.
The metal cloth serving as reinforcement, can be made of wire of 0.05 to 0.2 mm diameter. The material is chosen depending on whether the electrode will serve as the anode or the cathode. When the electrode serves as the anode, the material of the net of metal cloth is preferably Ta or Ti, and when the electrode serves as the cathode, the metal cloth is preferably nickel, brass, bronze or any other copper alloy.
The powder mixture of graphite and polytetrafluorethylene can be varied within the limits of 60-95% by weight graphite and 5-40% by weight polytetrafluorethylene. By changing the ratio of the mixture, mechanical stability and resistance as well as porosity and electrical conductivity of the electrode can be influenced within certain limits, and adapted to the respective conditions in optimum manner.
The ratio of the mixture of the catalyst can be 10-70% by weight RuO 2 and 90-30% by weight IrO 2 . After repeated experimentation it has been found that the catalyst mixture of RuO 2 /IrO 2 tends in an oxidizing atmosphere to a chemical-thermodynamical equilibrium at a very definite mixture ratio. A mixture of 20% by weight RuO 2 and 80% by weight IrO 2 has been found to be the most stable. The electrode is thus prepared in such an advantageous manner that the end product will contain precisely such as mixture ratio.
During the process of preparation of the electrode, the sintering as well as oxidizing can be effected at 340°-400° C.
This process can be applied in a particularly advantageous manner for the production of electrodes for high efficiency water electrolysis units in the production of hydrogen. Owing to its simplicity and economy, it is particularly suitable for the production in series of large-surface electrodes for large industrial plants.
The electrodes manufactured in this manner are characterized by a high chemical resistance and a favorable electrolytic voltage.
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.
Example of a Design for an Electrode
12.75 g (corresponding to 85% by weight) of graphite powder, grain sizes up to 0.1 mm, were ground in toluene in a ball mill for 6 hours with 2.25 g (corresponding to 15% by weight) of polytetrafluorethylene powder (for example "Teflon" 702N of Du Pontde Nemours). The suspension of graphite and polytetrafluorethylene particles in toluene prepared by this manner was dried in a drying oven for 3 hours to form a solid mass. Subsequently, the dried mass was broken up, ground and passed through a sieve with round holes of 0.25 mm diameter.
A piece of cloth made of tantalum wire (wire diameter is 0.09 mm; 1024 meshes per cm 2 ) was placed into a cylindrical flat matrix and covered with the above-mentioned powder mixture to a maximum height of approximately 2 mm. Attention is to be paid that the powder is uniformly distributed. Subsequently, the powder was compressed at room temperature for 50 seconds by means of a press under a pressure of 140 bar whereby a compact disc, rigidly connected with a metal cloth was obtained.
Finally, the pressed disc was subjected to a sintering process under argon atmosphere in accordance with the following program:
heating: 20°14 375°°C. at 2° C./minute
holding: 375° C. for 1/2 hour
cooling: 375°-20° C. at 2° C./minute
The disc produced in this manner was now inmersed in an alcoholic solution for 10 seconds, a solution which contained 12 relative % by weight of ruthenium chloride (RuCl 3 ) and 88 relative % by weight iridium chloride (IrCl 3 ). After letting it drip for one minute, the disc was oxidized in air for ten minutes at a temperature of 375° C. This process of inmersion and oxidizing was repeated a total of five times. At the end, the disc was once more oxidized in air for four hours at a temperature of 375° C. The electrode manufactured in this manner is characterized by a high chemical resistance and favorable electrolytic voltage.
Having now fully described this invention, it will be apparent to one of ordinary skill in the art that many changes and modifications can be made thereto without departing from the spirit or scope of the invention set forth herein. | An electrode for water electrolysis which comprises a solid solution of graphite and polytetrafluorethylene impregnated with a catalyst mixture of platinum metal oxides, the solid solution being pressed and sintered on a reinforcing net of metal cloth, as well as a process for preparing the electrode. The electrodes are useful in large scale water electrolysis for the production of hydrogen. | 2 |
RELATED APPLICATION
This is a continuation-in-part of U.S. patent application Ser. No. 832,147 filed Feb. 24, 1986, abandoned.
BACKGROUND
The present invention is directed to a method for stacking boxes on a pallet board. The invention is also directed to a brace useful in such method.
The use of pallet boards as an aid in the shipping of packaged goods is common in all areas of national and international commerce. The great advantage of palletized goods is the ease with which they can be maneuvered about a warehouse and the efficiency with which they can be moved into and out of cargo transport carriers.
With certain cargo, it is highly advantageous to be able to circulate a gaseous mixture among the palletized boxes and/or to be able to exhaust gases away from the palletized boxes. For instance, where the cargo needs to be refrigerated, it is desirable to be able to circulate chilled air among the palletized boxes. Also, where the cargo consists of fruits or vegetables, it is frequently desirable to be able to circulate gaseous ripening agents and/or insecticides among the palletized boxes. Some fruits, such as green bananas, give off a gas while they are in transit. Such gas results from the tendency of the fruit to ripen in the box. The gas will tend to build up and create pressure. Such pressure tends to create heat which in turn tends to accelerate the riping process (and the consequent evolution of gas). Thus, if the gas is not exhausted from among the boxes, the fruit will ripen rapidly and unevenly. Much of the cargo may even overripen and spoil.
Attempts to provide circulation around palletized boxes have been less than totally successful. One such attempt consists of stacking the palletized cargo on a grating which is slightly elevated above a floor. Gases are allowed to flow below the lower-most pallets (those actually sitting upon the grating), but gases are not free to flow among the boxes or along the sides or above the palletized cargo. Other attempts utilize perforated floors, walls and/or ceilings capable of allowing the free flow of gas around the palletized cargo but not around the individual palletized loads nor around the individual boxes. Where the need for ventilation is critical, warehouses and shippers resort to constructing customized bulkheads or shelving within the cargo storage area to separate each palletized load and thereby facilitate the flow of gases around them. Such custom construction is very expensive and does nothing towards ventilating the boxes which are located on the interior of the palletized load.
There is therefore a need for a device and a method for storing palletized cargo which will provide ventilation for all of the palletized boxes.
There is a further need for a device and a method for storing palletized cargo in such a way that individual palletized loads are ventilated, which device and method is less expensive and faster to implement than the construction of customized bulkheads or shelving.
SUMMARY
The present invention satisfies these needs. The invention provides a method for stacking at least two horizontal tiers of uniformly shaped boxes on a pallet board so as to create at least two open channels within each of the tiers. The method comprises the steps of:
(a) stacking each tier of boxes on the pallet board in a preselected configuration such that the sides of the boxes on the tier form at least two open channels in fluid communication with one another, at least one end of each of the channels being open to the exterior of the tier, and each channel being at least about 1" wide; and
(b) bracing the boxes to prevent them from shifting laterally into the open channels by interposing spacing elements between the boxes on opposite sides of the channels.
The spacing elements are disposed in fixed relationship to one another by a suitable rigid structural means.
DRAWINGS
These and other features, aspects and advantages of the present invention will become better understood with reference to the following description, appended claims and accompanying drawings where:
FIG. 1 is a perspective view of a first pallet load demonstrating features of the invention;
FIG. 2 is a perspective view of a second pallet load demonstrating features of the invention;
FIG. 3 is a perspective view of a first pallet load brace useful in the invention;
FIG. 4 is a perspective view of a second pallet load brace useful in the invention;
FIG. 5 is a perspective view of a third pallet load brace useful in the invention;
FIG. 6 is a top view of a fourth pallet load brace useful in the invention;
FIG. 7 is a top view of a fifth pallet load brace useful in the invention;
FIG. 8 is a perspective view of a third pallet load demonstrating features of the invention;
FIG. 9 is a perspective view of a sixth pallet load brace useful in the invention;
FIG. 10 is a cross-sectional view of one arm of the pallet load brace shown in FIG. 9;
FIG. 11 is a cross-sectional view of the second arm of the pallet load brace shown in FIG. 9;
FIG. 12 is a top view of the pallet load shown in FIG. 8;
FIG. 13 is a side view and partial cross-section of the pallet load shown in FIG. 8; and
FIG. 14 is a cross-sectional view of the pallet load shown in FIG. 13.
DESCRIPTION
The invention comprises a method for stacking boxes upon a pallet board and a brace useful in such method. As used herein, the term "pallet board" means any portable surface upon which boxes can be stacked. Typically, pallet boards are wooden surfaces constructed by appending a plurality of parallel slats orthogonally between two parallel side members.
With reference to FIGS. 1, 2, 6 and 7, a brace 10 comprises a plurality of spacing elements (shown in the Drawings as spacer blocks 12) affixed to a flat sheet 14.
The flat sheet 14 has a top side 16 and a bottom side 18 and provides a support for the spacer blocks 12. Preferably, the flat sheet 14, is a rigid structure so that the spacer blocks 12 remain in spaced relation to each other. Also, it is preferable that the sheet 14 be thin, to minimize the space it occupies, lightweight to facilitate its handling, and inexpensive. Materials such as plywood, plastics and cardboard are acceptable, with cardboard being the most preferred because of its low cost. Optionally, the sheet 14 can be perforated with vent holes 20 to permit vapor communication between the top side 16 and the bottom side 18.
The sheet 14 has a surface area of sufficient size and shape to provide a support for each of the blocks 12. For ease of handling and field alignment during pallet load assembly, it is preferable that the surface area of the sheet 14 has approximately the same size and shape as the tier of boxes upon which it is disposed when in use.
In operation, braces 10 are interposed between all of the tiers of boxes in the pallet board load 22. For additional load stability, it is preferable that a brace 10 also be placed beneath the lower-most tier of boxes. FIG. 1 illustrates a pallet load 22 consisting of three tiers of boxes and four braces 10: a lower-most brace 10a, a lower-most tier of boxes 24, a lower-middle brace 10b, a middle tier of boxes 26, an upper-middle brace 10c, an upper-most tier of boxes 24, and an upper-most brace 10d.
The spacer blocks 12 are disposed on the sheet 14 so as to provide a means for maintaining the separation of the boxes on each tier. Spacer blocks 12 having a cylindrical shape can be used in the invention. (As used herein, the term "cylinder" is broadly defined as the solid or hollow surface generated by a straight line moving always parallel to itself and describing any fixed curve [not necessarily a circle]. A cylinder has a regular transverse cross-section which may be of any shape. A cylinder may be hollow or solid.) The cylindrically-shaped spacer blocks 12 are disposed so that each of their ends abuts a box in a pallet load tier. In this way, one cylindrically shaped spacer block 12 separates two boxes in a tier by a distance equal to the length of the spacer block 12. Preferably the cylindrically shaped spacer blocks 12 have at least one flat side to facilitate attachment to the sheet 14.
The spacer blocks 12 are sufficiently large to maintain their position between the segregated boxes. In general, the blocks must be at least about 0.25 inches thick and preferably greater than about 0.5 inches thick. Cylinders having a 1"×1" square cross-section can be used.
The spacer blocks 12 can be constructed with a variety of materials. Since the lateral forces applied to the pallet load 18 are typically small, the spacer blocks 12 can often be constructed of relatively light materials. Wooden blocks can be used. Styrofoam and other light-weight materials are preferable because of their light weight and low cost.
The spacer blocks 12 are affixed to the sheet 14 by conventional means. Cementing the blocks to the sheet 14 with a glue is the preferred method because of its ease of implementation and low cost.
In an optional configuration illustrated in FIGS. 1 and 2, the spacer blocks 12 are affixed to a pair of parallel rails 30. The rails 30 can add rigidity to the spacer-sheet connection. For instance, where the spacer blocks 12 are wooden, they can be nailed to wooden rails 30 and the wooden rails 30 cemented to the sheet 14. The rails 30 also act as independent spacing means to maintain the segregation of the boxes.
The spacer blocks 12 are affixed to the sheet 14 so as to provide a means to segregate at least some of the boxes on each of the tiers on opposite sides of and adjacent to an open channel (shown in FIGS. 1, 2, 8, 13 and 14 as cylindrical void space 32) which is horizontally disposed within the tier. Brace 10c in FIG. 1, for instance, segregates the boxes on an upper tier of boxes (the upper-most tier 28), on opposite sides of a cylindrical first void space 32a and segregates the boxes on a lower tier of boxes (the middle tier 26) on opposite sides of a cylindrical second void space 32b. Where the boxes have a rectangular cross-section, the cylindrical void spaces 32 have a rectangular cross-section.
A first group of spacer blocks 12 are affixed to the underside 18 of the sheet 14 such that the midpoint of each block 12 is aligned along a first straight line 34. Each block is disposed perpendicular to the first line 34. A second group of spacer blocks 12 are affixed to the top side 16 of the sheet 14 such that the midpoint of each block 12 is aligned along a second straight line 36.
In a first embodiment illustrated in FIG. 1, the first line 34 is perpendicular to the second line 36 so that the first line 34 may be disposed in the same vertical plane as the longitudinal axis 38 of the pallet board 40 while the second line 36 can be disposed in the same vertical plane as the lateral axis 42 of the pallet board 40. In the first embodiment illustrated in FIG. 1, the configuration of the first straight line 34 facilitates the segregating of boxes on either side of the void space 32a, whose longitudinal axis is disposed in the same vertical plane as the longitudinal axis 38 of the pallet board 40. Also in the first embodiment illustrated in FIG. 1, the configuration facilitates the segregating of boxes on either side of a void space in the tier above brace 10d (not shown), whose longitudinal axis is disposed in the same vertical plane as the lateral axis 42 of the pallet board 40. The longitudinal axis of the void space in the tier above the brace 10d is preferably perpendicular to the longitudinal axis of the void space 32a to facilitate the cross-stacking of boxes in the pallet load 22.
The first embodiment illustrated in FIG. 1 is ideally configured to cross-stack six substantially uniformly shaped boxes per tier, three boxes per tier on either side of the cylindrical void space 32. The boxes on each side of the cylindrical void space 32 abut each other along one side and abut the cylindrical void space 32 at one end. For convenience, the pallet board 40 can be square and can be selected with the length of a side equal to three times the width of each box and with the length of the side being greater than twice the length of each box. When the pallet board 40 is so selected, the spacer blocks 12 are of uniform length x which is equal to the length of the pallet board 40 less twice the length of one of the boxes. This configuration allows a pallet load 22 with a square cross-section to be assembled on the pallet board 40, has a perimeter coincident with the perimeter of the pallet board 40, and has horizontal, cylindrical void spaces 32 each of which has a rectangular cross-section with a horizontal width x. The value x is preferably between about 4 and 7 inches to maximize pallet load rigidity which providing adequate ventilation along one end of each of the boxes. The first embodiment illustrated in FIG. 1 facilitates the building of pallet loads 22 which have several cylindrical void spaces 32, each at a predetermined elevation. This configuration allows the user to stack pallet loads 22 in his cargo storage facility such that each of the cylindrical avoid spaces 32 abut one another, thereby linking together to form a continuous ventilation channel throughout the entire cargo storage facility. The totality of these continuous channels facilitates the efficient influx and outflux of gases among each and every box in the cargo storage facility.
In the second embodiment illustrated in FIG. 2, the first line 34 is parallel to the second line 36. The second embodiment illustrated in FIG. 2 further comprises a third line 46 and a fourth line 48. The third line 46 is disposed in the same horizontal plane as the first line 34 and is perpendicular to the first line 34 so that the third line 46 can be disposed in the same vertical plane as the lateral axis 42 of the pallet board 40. The fourth line 48 is disposed in the same plane as the second line 36 and is perpendicular to the second line 36 so that the fourth line 48 can be disposed in the same vertical plan as the lateral axis 42 of the pallet board 40. In the second embodiment illustrated in FIG. 2, the configuration of the first straight line 34 facilitates the segregating of boxes on either side of an upper longitudinal void space 32c disposed above the sheet 14. Also in the second embodiment illustrated in FIG. 2, the configuration facilitates the segregating of boxes on either side of a longitudinal lower void space 32d disposed below the sheet 14. Further, the configuration illustrated in FIG. 2 facilitates the segregating of boxes on either side of a lower transverse void space 32e which is disposed horizontally below the sheet 14 perpendicular to the longitudinal lower void space 32d and extending from the longitudinal lower void space 32d to the side of the sheet 14 which is parallel with and closest to the second straight line 36. Finally, the configuration illustrated in FIG. 2 facilitates the segregating of boxes on either side of an upper transverse void space 32f which is disposed horizontally above the sheet 14 perpendicular to the upper longitudinal void space 32c and extending from the upper longitudinal void space 32c to the side of the sheet 14 which is parallel with and closest to the fist straight line 34.
The second embodiment illustrated in FIG. 2 is ideally configured to cross-stack five substantially uniformly shaped boxes per tier. Three of the boxes are aligned side by side with one end abutting the longitudinal void space. The other two boxes are disposed on the opposite side of the longitudinal void space with a side abutting the longitudinal void space and with opposing interior ends strattling the lateral void space. Preferably, to maximize pallet load rigidity while providing adequate ventilation, the width of the longitudinal void space is between about 1 and 3 inches and the width of the lateral void space is between about 4 and 6 inches. For uniformity, it is preferable that the width of the upper longitudinal void space 32c is substantially the same as the width of the lower longitudinal void space 32d, and that the width of the lower transverse void space 32e is substantially the same as the width of the upper transverse void space 32f.
FIGS. 3, 4 and 5 illustrate embodiments of the invention wherein the spacer blocks 12 are supported by rails 30 instead of a flat sheet 14. The rails 30 may be constructed of any suitable support material. Wood, plastics and stiff cardboard are suitable, with wood being preferred be cause of its rigidity, light weight and low expense. 1.5"×0.25" slats have been found to be suitable for most conventional pallet loads such as those having a horizontal cross-sectional area of about 2,000 sq. inc. Preferably, the rails 30 are rigid so as to maintain the spacer blocks 12 in spaced relation to the one another.
FIG. 3 illustrates an embodiment of the invention having a spacer block 12 arrangement similar to that used in the embodiment illustrated in FIG. 1. The embodiment illustrated in FIG. 3 is used in substantially the same way as the embodiment illustrated in FIG. 1. FIG. 4 illustrates an embodiment having a spacer block 12 arrangement similar to that used in the embodiment illustrated in FIG. 2. The embodiment illustrated in FIG. 4 is used in substantially the same way as the embodiment illustrated in FIG. 2.
FIG. 5 illustrates an embodiment of the invention wherein the rails 30 provide the sole means for separating the boxes on each pallet tier. In this embodiment, the rails 30 are sufficiently thick to maintain each box in place. 1"×1" wooden members can be used to construct rails 30 suitable for most conventional pallet loads such as those having a horizontal cross-sectional area of about 2000 sq. in. In the embodiment illustrated in FIG. 5 an optional thin plate 44 is used to add additional strength to the brace 10. FIG. 5 is analogous to and is used in substantially the same way as the embodiment illustrated in FIG. 2.
FIGS. 8, 12, 13 and 14 illustrate a method for stacking tiers of uniformly shaped boxes on a pallet board using a T-shaped pallet board brace 50. The T-shaped pallet board brace 50 is illustrated in FIGS. 9, 10 and 11.
The T-shaped pallet board brace 50 comprises a short, stem arm spacing element 52, one end of which is affixed at the midpoint of, and perpendicular to, a long, cross-arm spacing element 54.
The boxes, T-shaped pallet board brace 50 and/or pallet board 40 are configured so that the width of the pallet board 40 has approximately the same linear dimension as the sum of (i) the length 56 of one of the boxes, (ii) the width 58 of one of the boxes, and (iii) the width 59 of the long, cross-arm 54 of the T-shaped pallet board brace 50. The boxes, T-shaped pallet board brace 50, and/or pallet board 40 are also configured such that the length 60 of the pallet board 40 has approximately the same linear dimension as the sum of (i) twice the length 56 of one of the boxes plus (ii) the width 62 of the short, stem arm 52 of the T-shaped pallet board brace 50.
Each tier is disposed in a preselected configuration with three of the five boxes in the tier set side by side such that their respective ends are aligned with the length 60 of the pallet board 40. The other two boxes in the tier are disposed end to end such that a side of each box is aligned with the opposite side of the pallet board 40. The ends of the two boxes facing each other are spaced apart by a distance approximately equal to the width 62 of the short, stem arm 52 of the T-shaped pallet board brace 50. As disposed in this preselected configuration, the ends of the first three boxes are spaced apart from the sides of the remaining two boxes by a distance approximately equal to the width 59 of the long, cross-arm 54 of the T-shaped pallet board brace 50.
The T-shaped pallet board brace 50 is interposed within the two open channels 32 formed by the preselected configuration of the five boxes, to prevent the boxes from shifting laterally into the opened channels 32.
The T-shaped pallet load brace 50 may be composed of any suitable material such as wood, metal, plastic, styrofoam, etc. A highly desirable material is corrugated cardboard because of its inexpensiveness.
Each arm of the T-shaped pallet load brace 50 shown in FIGS. 9, 10 and 11 is comprised of two layers of corrugated cardboard affixed firmly together, such as with glue. Cutouts 64 and notches 66 can be made in each of the arms to minimize material and weight.
Each arm need be only as thick as necessary to mechanically block the boxes on each tier from shifting laterally into the open channels 32. Generally the thickness must be greater than about 1/8". Thicknesses of 1/4" and greater are preferred.
EXAMPLE
FIG. 6 illustrates a first example of a brace embodying features of the invention. FIG. 7 illustrates a second example of a brace embodying features of the invention. In both examples, the sheet 14 is constructed of cardboard and the spacer blocks 12 are constructed of wooden cylinders having a 1"×1" square cross-section.
Both examples are suitable for use in palletizing boxes having a parallelepiped shape with top and bottom dimensions of about 15"×201/2", side dimensions of about 9"×201/2", end dimensions of about 9"×15", and having an approximately 9"×31/2" rectangular opening disposed length-wise in the center of the top and the bottom. Such boxes are commonly used on the West Coast for transporting green bananas.
The first example illustrated in FIG. 6 can be used to cross-stack six boxes per tier in the same way as the embodiment illustrated in FIG. 1. The configuration of the first example allows for lateral ventilation across the interior each of each box along channels created by the spacer blocks 12. It also allows for vertical ventilation up through the center of each box via the vent holes 20. The second example illustrated in FIG. 7 can be used to cross-stack five boxes per tier in the same way as the embodiment illustrated in FIG. 2. The configuration of the second example allows for lateral ventilation across the interior ends and/or sides of each box along channels created by the spacer blocks 12. It also allows for vertical ventilation up through the center of each box via the vent holes 20.
The present invention provides an inexpensive and easily employed brace for stacking boxes on a pallet board in a fixed configuration wherein vapor channels are created within the palletized cargo to allow for the free flow of gas to and/or from each box. The invention is especially useful in stacking cargo boxes containing perishable items in need of refrigeration and in stacking cargo boxes containing fruit such as bananas which give off a gas which must be exhausted from the cargo during transit.
Although the present invention has been described in considerable detail with reference to certain preferred versions, other versions are possible. For instance, the spacer blocks 12 need not be cylindrically shaped. Nodes of any shape can be used as they are capable of maintaining the separation between boxes on each tier. Therefore the spirit and scope of the appended claims should not necessarily be limited to the description of the preferred versions contained herein. | Provided is (i) a method for reinforcing pallet board loads having internal ventilation channels and (ii) a pallet board brace useful in such method. The method comprises:
(a) stacking each tier of the pallet board load in a preselected configuration such that the sides of the boxes on each tier form at least two open channels in fluid communication with one another, wherein at least one end of each channel is open to the exterior of the tier and wherein each channel is at least one inch wide; and
(b) bracing the boxes to prevent them from shifting laterally into the open channels by interposing spacing elements between the boxes on opposites sides of the channels, the spacing elements being disposed in fixed relationship to one another by a suitable rigid structure. | 8 |
This is a continuation of application Ser. No. 709,369 filed July 28, 1976 now abandoned.
BACKGROUND OF THE INVENTION
The present invention is concerned with a novel seat belt assembly for use in vehicles, having rich energy absorbing property and by which the retracting amount by the retractor is increased, thereby promoting use of the retractor.
The seat belts have generally been employed to mitigate mechanical shocks to the passengers of vehicles such as automobiles and air craft resulting to provide safety performance. The seat belts of this sort were so far studied from various aspects and angles, and many proposals were so far presented.
In the early days, the belts were manufactured in two-point type to hold only the waist, but to attain more reliable safety performance, the belts were made in three-point type having an additional belt to hold the shoulder. In recent days there has been proposed the belts of the type in which the waist belt and the shoulder belt are made in a continuous form. The belt system of the aforesaid continuous type has an advantage that they need just only less retractor units than retractor units required by the aforesaid three-point belt system. The modern trend, however, has been placing increasing demand for the belts to provide more energy absorption, which has resulted in the use of shoulder belts having large absorption of energy. However, the belts of the aforesaid continuous type have to be made by joining together an ordinary belt and a belt having high energy absorption. Hence the joined place gives an uncomfortable touch feeling to the human body, and comes into contact with the guide members of the retractor when the belt is not being taken up along smooth retracting movement. It is, therefore, desired to make the belt with a single woven fabric without seams to improve the aforementioned defects. At present, however, to make such a belt is technically difficult and no satisfactory solution has been found.
In recent years, increased concern with regard to the improvement of retractors has resulted in the manufacture of retractors of various types. Such retractors, however, have all been design based on a prerequisite that the thickness of the belt is equal along the lengthwise direction, thereby imposing a limit to the amount of taking up the belt. To increase the take-up amount, the retractor must have increased volume, losing economy in space, particularly when it is used for the vehicles having narrow room. This is a fatal defect of the belt of the aforementioned continuous webbing type, losing the balance of whole parts of the vehicle. From such viewpoint, it is an important assignment to increase the take-up space just with using a retractor of an ordinary size.
SUMMARY OF THE INVENTION
The inventor of the present invention has conducted extensive study in an effort to solve the aforementioned defects by giving attention to the aforesaid various points, and has found an effective means by which the belts can be formed continuously as a single unit based on the characters required for the shoulder belt and the waist belt.
It is known, in general, that the shoulder belt requires less tensile strength than the waist belt. For example, the waist belt requires a tensile strength of more than 2700 kg, whereas the shoulder belt requires only tensile strength of up to 1800 kg. Particularly, it was confirmed by experiments conducted by the U.S. National Highway Transport Safety Agency (NHTSA) that where a belt having property to absorb energy is used for the shoulder belt, the tensile strength needs not necessarily be 1800 kg, but may be sufficient if the belt has a tensile strength of 500 kg. It is, therefore, recognized that the shoulder belt may have less thickness than that of the waist belt and may have less strength to sufficiently attain the desired object.
The seat belt of the present invention was designed under the above said situations and comprises a seamless and continuous webbing having a belt to hold the waist and a belt to hold the shoulder, characterized in that the belt portion of holding the shoulder of said webbing is thinner and has less strength than the waist portion of the belt, and further has an extension property that does not restore to the initial state under a certain load condition that substantially causes the belt to extend by a certain length. The invention is illustrated below with reference to a concrete embodiment shown in the accompanying drawings. But it should be noted that the present invention is not restricted to the below mentioned embodiment only but permits various design modifications without departing from the objects of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view showing an example of using the seat belt of the present invention.
FIG. 2 is a partially omitted perspective view showing the appearance of the seat belt of the present invention.
FIG. 3 is a diagram showing an example of the texture of the waist belt of the seat belt of the present invention.
FIG. 4 is a diagram to show an example of the texture of a selvage of the seat belt of the present invention.
FIG. 5 is a vertical cross-sectional view showing the texture of FIG. 3 of the waist belt of the seat belt of the present invention.
FIG. 6 is a diagram showing an example of the texture of the shoulder belt of the seat belt of the present invention.
FIG. 7 is a vertical cross-sectional view showing the texture of FIG. 6 of the same seat belt.
FIG. 8 is a vertical cross-sectional view showing the texture at the boundary part of the waist belt and the shoulder belt of the seat belt of the present invention, and
FIG. 9 is a diagram showing curves of load and extension of the waist belt and the shoulder belt of the seat belt of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 shows a diagram to illustrate an example in which a seat belt of the present invention is employed, in which the reference numeral 1 stands for a shoulder belt, and the reference numeral 2 represents a waist belt. These two belts 1 and 2 form a belt made of a single continuous webbing via a boundary part 3 as shown in FIG. 2. The shoulder belt 1 is thinner than the waist belt 2. The belt composed of these shoulder belt 1 and waist belt 2 will usually have a retractor 4 and a fastening fitting 5. The belt is passed through a slidable tongue piece 6 locating as a middle suspending matter; the slidable tongue piece 6 will be engaged with a buckle 7 which is suspended to an anchorage hole 8 selected within the vehicle inside. The reference numeral 9 is a member to guide and direct the shoulder belt position 1 that was pulled out from the retractor 4 fixed on some place of the side wall. The member 9 is not necessary if the retractor is provided here at this position. Also, the reference numeral 10 represents a seat in the vehicle.
FIGS. 3 to 5 are diagrams to show an example of weaving waist belt 2, FIG. 6 and 7 are diagrams to show an example of a woven texture of the shoulder belt 1, and FIG. 8 shows an embodiment of a texture at the boundary part 3 between portion belt 1 and 2. In the drawings, the reference numerals 11, 12, 13, 14, 15 and 16 are warps in a complete texture. The above warps are arrayed in many number in parallel, and to both sides thereof are added warps 21, 22, 23 and 24 having selvage shown in FIG. 4 to determine the belt width of the present invention. The reference numerals 31 and 32 are warps having smaller elongation than the warps 11 to 16. Further, the reference numerals 41, 42, 43, 44, 45 and 46 are wefts in the waist belt 2, and the reference numerals 51, 52, 53, 54, 55, 56, 57 and 58 are wefts in the shoulder belt 1. In FIGS. 3 to 5, the aforesaid warps 11 to 16 and 31, 32 are crossed and interlinked by the wefts 41 to 46 by way of triple weaving shown in FIG. 3 to form the waist belt 2. In this case, the selvage texture shown in FIG. 4 is added to both sides of fabrics in FIG. 3. In FIGS. 6 and 7, the warps 11, 12, 14 and 15 among the warps 11 to 16 and 31, 32 in the aforesaid waist belt 2 are crossed and interlinked together with the wefts 51 to 58 and double weaving of wefts diagramatized in FIG. 6 and further the warps 13 and 16 are floated, without being woven and arrayed in parallel, outside of the aforesaid crossed and bonded texture. The warps 31, 32 are crossed and interlinked with the wefts in the aforesaid waist belt 2, and are running as core yarns being retained inside of the texture composed of warps 11, 12, 14, 15 and wefts 51 to 58, as seen in FIG. 7; the warps 31, 32 are not exposed outside of the texture. As mentioned above, the fabric of the shoulder belt 1 of the present invention is formed by the interrelated function among the warps 11, 16, 31, 32 and wefts 51 to 58.
The aforesaid selvage texture diagramatized in FIG. 4 is also added to both sides of the shoulder belt 1. Here the aforesaid waist belt 2 and the shoulder belt 1 are constituted as a single continuous webbing without seam. In this texture, the boundary part 3 between the two belts 1 and 2 is shown in FIG. 8. That is, the warps 11, 12, 14, 15, 31 and 32 forming the waist belt 2 are taken over by the fabric of the shoulder belt 1. The floating warps 13 and 16 are cut away at a part A where they appear out of the fabric. The cut-away part is then removed appropriately, and the position A at the end is then dyed and transferred to the position B of FIG. 8, and then buried and retained in the texture of the waist belt 2. In this way, a continuous seamless webbing is formed with the waist belt 2 and the shoulder belt 1 together. In the foregoing description, the warps are preferably cut away in an amount within the range of 10 to 40% in relation to the thickness and strength of the belt, so that the thickness is reduced into appropriately favorable value relative to the thickness of the waist belt 2.
Although the foregoing description has dealt with the transfer from the waist belt 2 toward the shoulder belt 1, it should be noted that the webbing of the present invention is made for manufacturing a long texture in which the waist belt 2 and the shoulder belt 1 are repeated alternately; the same structure is repeated from the shoulder belt 1 toward the waist belt 2. However, here, as for the order of wefts, the weft 41 in place of weft 46 in the waist belt 2 is woven next of the weft 58 of the shoulder belt 1. Materials of wefts and warps for use in the webbing texture of the present invention may be thermoplastic synthetic fibers such as nylon, vinylon, polyester, polyprene esters, and various fibers such as viscose rayon, cotton, hemp, etc. Among the above thermoplastic synthetic fibers, particularly preferred examples are nylon and polyester fibers. These fibers may often be employed by being mixed together. The warps 31 and 32 that serve as core yarns may be made of a polyester fiber, vinylon, metallic fiber and glass fiber. Particularly preferred example may be a reformed fiber that is known as fiber B having less elongation. The core yarns, however, are selected best by comparison with the warps constituting the fabric.
The webbing by which the waist belt 2 and the shoulder belt 1 are connected for a single unit, is terminated to the aforesaid retractor 4 and to the fastening fitting 5, and is used for a seat belt as shown in FIG. 1. Also, in this case, the mounting positions of the retractor 4, fastening fitting 5, buckle 7 and indoor member 9 cannot be limited to the positions shown in FIG. 1 but may be mounted at any appropriate positions. In the present invention, in particular, the shoulder belt 1 is thin and is allowable to be mounted directly on the seat 10, which possibility is an advantage of the belt of the present invention.
When mechanical impact is applied to the aforementioned seat belt, the waist belt 2 having large strength and thickness securely holds the human body, and the shoulder belt 1 which is made thin and has smaller strength undergoes stretch easily when the impact is applied, whereby the core yarns are broken step by step in order, and then the determined load is reached and further acting point extends to a set point P shown in FIG. 9 to absorb the energy exerted on the human body. FIG. 9 shows this state, wherein the load and extending elongation degree exerted on the waist belt 2 as measured under the Standard, is diagramatized in diagram (a). The diagram (a) shows less degree of elongation and less work done. However, if the elongation of the shoulder 1 is set at 30%, for example, under a determined load of 300 kg, the core yarns will be broken down step by step at around 300 kg loaded, so that the flat portion such as in the diagram (b) may continue from an extension degree about 4 to 8% started to a set point P of about 30% indicated there. Further, if the loading is increased up to 1130 kg specified value under the Spec. MVSS, the extension reaches about 45%, at which the belt does not restore to the initial state (length) even after the load of 1130 kg is removed; the amount of work done is very large as compared to that of the waist belt 2. From the abovementioned fact, even a single continuous seamless webbing has the performance being comparable to a conventional three-point type seat belt employing energy-absorbing belt for a shoulder belt. The fact proves that the seat belt by the present invention has excellent performance.
Here the aforementioned predetermined load and set point will be selected depending upon the waist belt 2 and the shoulder belt 1 of the belt over the range of 150 to 1000 kg and from 20% to 40% of the point P.
As mentioned above, the seat belt of the present invention is made of a continuous and seamless webbing including the waist portion 2 and the shoulder portion 1, contributing to reduce the number of retractors that will have to be installed in the vehicle room. Moreover, since the webbing of shoulder portion 1 can be made thin and can be taken up by the retractor, it is allowed to make the retractor in small size or to have both the shoulder portion 1 and the waist portion 2 contained in a conventional retractor case. Therefore, in addition to reducing the number of retractors to be used, reasonable use of the retractor can be promoted and the seat belts can be attached to the vehicle room properly. In addition, the seat belt by the present invention, which is made of a single seamless and continuous belt, exhibits excellent performance to absorb energy which is comparable to conventional three-point type energy-absorbing belts. Besides, the belt by the present invention without seams permits the slidable tongue piece to slide smoothly, so that said slidable tongue piece can be retained at any proper and balanced positions to fasten the belts. In case of collision, the impact due to the collision is dispersed between the waist belt and the shoulder belt owing to free sliding of the slidable tongue piece to secure the safety of the human body. The slidable tongue piece also gives improved contact feeling to the human body. As mentioned in the foregoing, the seat belt by the present invention possesses various excellent effects exhibiting rich energy-absorbing performance and meets the demand required by modern vehicles.
While there have been described and illustrated preferred embodiments of the present invention it is apparent that numerous alterations, insertions and additions may be made without departing from the spirit thereof. | A seamless combined vehicle safety shoulder and waist belt has a shoulder section which is plastically elongatable and of high energy absorption, and a waist section of high tensile strength. The shoulder section is thinner than the waist section, the shoulder section including weft interwoven warps and linear core warps enclosed between the opposite faces of the shoulder section, and the waist section includes all of the shoulder section warps and additional warps, all the waist section warps being interwoven with wefts. In producing the belt, it is continuously woven with successive alternate waist and shoulder sections, the warps which form the waist sections and not in the shoulder sections floating in the shoulder sections and being thereafter severed proximate the areas of junction. | 3 |
FIELD OF THE INVENTION
The present invention relates to the field of solid-state image sensing devices; more specifically, it relates to CMOS based pixel sensor cell devices, methods of fabricating CMOS based pixel sensor cell devices and design structures for CMOS based pixel sensor cell devices.
BACKGROUND
Current CMOS (complementary metal oxide semiconductor) based image sensors suffer from one of two deficiencies depending upon the shutter system used. In rolling shutter systems the pixel sensor cells are exposed at different times. In global shutter systems, the signal strength from the pixel sensor cells can vary. In both cases, less than ideal images are produced. Accordingly, there exists a need in the art to mitigate the deficiencies and limitations described hereinabove.
SUMMARY
A first aspect of the present invention is a pixel sensor cell, comprising: a photodiode body in a first region of a semiconductor layer; a floating diffusion node in a second region of the semiconductor layer, a third region of the semiconductor layer between and abutting the first and second regions; and dielectric isolation in the semiconductor layer, the dielectric isolation surrounding the first, second and third regions, the dielectric isolation abutting the first, second and third regions and the photodiode body, the dielectric isolation not abutting the floating diffusion node, portions of the second region intervening between the dielectric isolation and the floating diffusion node.
A second aspect of the present invention is a method of fabricating a pixel sensor cell, comprising: forming a photodiode body in a first region of a semiconductor layer; forming a floating diffusion node in a second region of the semiconductor layer, a third region of the semiconductor layer between and abutting the first and second regions; and forming dielectric isolation in the semiconductor layer, the dielectric isolation surrounding the first, second and third regions, the dielectric isolation abutting the first, second and third regions and the photodiode body, the dielectric isolation not abutting the floating diffusion node, portions of the second region intervening between the dielectric isolation and the floating diffusion node.
A third aspect of the present invention is a design structure comprising design data tangibly embodied in a machine-readable medium, the design data being used for designing, manufacturing, or testing an integrated circuit, the design data comprising information describing a pixel sensor cell the pixel sensor cell comprising: a photodiode body in a first region of a semiconductor layer; a floating diffusion node in a second region of the semiconductor layer, a third region of the semiconductor layer between and abutting the first and second regions; and dielectric isolation in the semiconductor layer, the dielectric isolation surrounding the first, second and third regions, the dielectric isolation abutting the first, second and third regions and the photodiode body, the dielectric isolation not abutting the floating diffusion node, portions of the second region intervening between the dielectric isolation and the floating diffusion node.
These and other aspects of the invention are described below.
BRIEF DESCRIPTION OF THE DRAWINGS
The features of the invention are set forth in the appended claims. The invention itself, however, will be best understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawings, wherein:
FIG. 1A is a top view and FIGS. 1B , 1 C, 1 D and 1 E are cross-sections through respective lines 1 B- 1 B, 1 C- 1 C, 1 D- 1 D and 1 E- 1 E of FIG. 1A illustrating fabrication of a pixel sensor cell according to embodiments of the present invention;
FIG. 2A is a top view and FIGS. 2B , 2 C, 2 D and 2 E are cross-sections through respective lines 2 B- 2 B, 2 C- 2 C, 2 D- 2 D and 2 E- 2 E of FIG. 2A illustrating continuing fabrication of a pixel sensor cell according to embodiments of the present invention;
FIG. 3A is a top view and FIGS. 3B , 3 C, 3 D and 3 E are cross-sections through respective lines 3 B- 3 B, 3 C- 3 C, 3 D- 3 D and 3 E- 3 E of FIG. 3A illustrating continuing fabrication of a pixel sensor cell according to embodiments of the present invention;
FIG. 4A is a top view and FIGS. 4B , 4 C, 4 D and 4 E are cross-sections through respective lines 4 B- 4 B, 4 C- 4 C, 4 D- 4 D and 4 E- 4 E of FIG. 4A illustrating continuing fabrication of a pixel sensor cell according to embodiments of the present invention;
FIG. 5A is a top view and FIGS. 5B , 5 C, 5 D and 5 E are cross-sections through respective lines 5 B- 5 B, 5 C- 5 C, 5 D- 5 D and 5 E- 5 E of FIG. 5A illustrating continuing fabrication of a pixel sensor cell according to embodiments of the present invention;
FIG. 5F is a cross-section illustrating gate structures through line 5 B- 5 B of FIG. 5A ;
FIG. 6A is a top view and FIGS. 6B , 6 C, 6 D and 6 E are cross-sections through respective lines 6 B- 6 B, 6 C- 6 C, 6 D- 6 D and 6 E- 6 E of FIG. 6A illustrating continuing fabrication of a pixel sensor cell according to embodiments of the present invention;
FIG. 7A is a top view and FIGS. 7B , 7 C, 7 D and 7 E are cross-sections through respective lines 7 B- 7 B, 7 C- 7 C, 7 D- 7 D and 7 E- 7 E of FIG. 7A illustrating continuing fabrication of a pixel sensor cell according to embodiments of the present invention;
FIG. 8A is a top view and FIGS. 8B , 8 C, 8 D and 8 E are cross-sections through respective lines 8 B- 8 B, 8 C- 8 C, 8 D- 8 D and 8 E- 8 E of FIG. 8A illustrating continuing fabrication of a pixel sensor cell according to embodiments of the present invention;
FIG. 9A is a top view and FIGS. 9B , 9 C, 9 D and 9 E are cross-sections through respective lines 9 B- 9 B, 9 C- 9 C, 9 D- 9 D and 9 E- 9 E of FIG. 9A illustrating continuing fabrication of a pixel sensor cell according to embodiments of the present invention;
FIGS. 10A , 10 B, 10 C and 10 D illustrate alternative structures for the storage node of a pixel sensor cell according to embodiments of the present invention;
FIG. 11 is a top view of illustrating interconnections of the structural elements in a pixel sensor cell circuit;
FIG. 12 is a circuit diagram of a pixel sensor cell circuit according to embodiments of the present invention.
FIG. 13 is a diagram illustrating an array of global shutter pixel sensor cells according to embodiments of the present invention; and
FIG. 14 shows a block diagram of an exemplary design flow 400 used for example, in semiconductor IC logic design, simulation, test, layout, and manufacture.
DETAILED DESCRIPTION
Solid state imaging devices contain CMOS based pixel sensor cells arranged in an array of rows and columns and a shutter mechanism to expose the pixel sensor cell array.
In rolling shutter methodology the image is captured on a row-by-row basis. For a given row the image is captured by photodiodes, transferred to floating diffusion nodes, and then the nodes are read out to column sample circuits before moving on to the next row. This repeats until the all the pixel sensor cell rows are captured and read out. In the resulting image each row represents the subject at a different time. Thus for highly dynamic subjects (such as objects moving at a high rate of speed) the rolling shutter methodology can create image artifacts.
In a global shutter methodology, the image is captured for the whole frame in the photodiodes at the same time for all the rows and columns of the pixel sensor cell array. Then the image signal is transferred to the floating diffusion nodes where it is stored until it is read out on a row-by-row basis. The global shutter method solves the problem with image capture of high speed subjects, but introduces the problem of charge level change on the charge storage node of the pixel sensor cell.
In the rolling shutter method, the image signal is held in the charge storage nodes for a significantly shorter time than the actual time of exposure of the photodiode, and this hold time is the same for all pixel sensor cells in the array, making correction for charge level change in storage node simple with standard CDS techniques. In the global shutter method, the image signal is held in the storage node for varying amounts of time. The time in the first row being the shortest time (the time to read out a single row) with the time in the last row being the longest time (the time to read all rows). Thus any charge generation or leakage occurring on storage node can have a significant impact to the signal being read out of the row.
In order to improve on the global shutter efficiency the embodiments of the present invention reduce the amount of change to the charge being held on the floating diffusion node of the pixel sensor cell. The embodiments of the present invention use unique well and floating diffusion node ion implantation design levels/masks to create floating diffusion nodes that have minimal dark current generation and leakage caused by stray carriers that may be generated in adjacent semiconductor regions. In embodiments of the present invention, the drain ion implant design level/mask leaves a space between the floating diffusion node and the dielectric isolation sidewalls. The well ion implantation design level/mask is designed such that the well extends under the floating diffusion node and the dielectric isolation.
Optionally, an electron shield ion implantation design level/mask is provided. Optionally, a dielectric trench sidewall passivation ion implantation design level/mask is provided, which reduces carrier generation that can occur along the dielectric isolation sidewall surfaces. Optionally a surface pinning ion implantation design level/mask is provided which passivates the surface of the photodiode and the floating diffusion node. The fabrication process infra is presented in a preferred order, but other orders are possible.
FIG. 1A is a top view and FIGS. 1B , 1 C, 1 D and 1 E are cross-sections through respective lines 1 B- 1 B, 1 C- 1 C, 1 D- 1 D and 1 E- 1 E of FIG. 1A illustrating fabrication of a pixel sensor cell according to embodiments of the present invention. In FIGS. 1A , 1 B, 1 C, 1 D and 1 E, formed on semiconductor layer 100 is dielectric trench isolation 105 . In one example, semiconductor layer 100 is a single crystal silicon substrate or an epitaxial single crystal silicon layer on a single crystal silicon or semiconductor substrate. In one example, semiconductor layer is an upper semiconductor layer (which may be a single crystal silicon layer) of a semiconductor-on-insulator substrate comprising the upper semiconductor layer separated from a lower semiconductor layer (which may be a single crystal silicon layer) by a buried oxide (BOX) layer. Dielectric isolation 105 is formed, for example, by photolithographically defining and etching a trench in substrate 100 , then filling the trench with a dielectric material (e.g., SiO2) and performing a chemical-mechanical-polish to coplanarize a top surface 106 of dielectric isolation with a top surface 107 of substrate 100 . In one example, semiconductor layer 100 is doped P-type.
A photolithographic process is one in which a photoresist layer is applied to a surface of a substrate, the photoresist layer exposed to actinic radiation through a patterned photomask (fabricated based on a design level) and the exposed photoresist layer developed to form a patterned photoresist layer. When the photoresist layer comprises positive photoresist, the developer dissolves the regions of the photoresist exposed to the actinic radiation and does not dissolve the regions where the patterned photomask blocked (or greatly attenuated the intensity of the radiation) from impinging on the photoresist layer. When the photoresist layer comprises negative photoresist, the developer does not dissolve the regions of the photoresist exposed to the actinic radiation and does dissolve the regions where the patterned photomask blocked (or greatly attenuated the intensity of the radiation) from impinging on the photoresist layer. After processing (e.g., an etch or an ion implantation), the patterned photoresist is removed. Processing results in a physical change to the substrate.
FIG. 2A is a top view and FIGS. 2B , 2 C, 2 D and 2 E are cross-sections through respective lines 2 B- 2 B, 2 C- 2 C, 2 D- 2 D and 2 E- 2 E of FIG. 2A illustrating continuing fabrication of a pixel sensor cell according to embodiments of the present invention. In FIGS. 2A , 2 C and 2 D an optional dielectric passivation layer 110 is formed in semiconductor layer 100 along selected surfaces of dielectric isolation. Dielectric passivation layer 110 is formed, in one example, by photolithographically defining and then ion implanting a selected region of substrate 100 . In one example, dielectric passivation layer 100 is doped P-type. In FIGS. 2C and 2D dielectric passivation layer 110 extends along the sidewalls and bottom surfaces of dielectric isolation 105 . FIG. 2C illustrates a region of semiconductor layer 100 where a photodiode will be subsequently formed and FIG. 2D illustrates a region of the semiconductor layer 100 where a floating diffusion node will be subsequently formed.
FIG. 3A is a top view and FIGS. 3B , 3 C, 3 D and 3 E are cross-sections through respective lines 3 B- 3 B, 3 C- 3 C, 3 D- 3 D and 3 E- 3 E of FIG. 3A illustrating continuing fabrication of a pixel sensor cell according to embodiments of the present invention. In FIGS. 3A , 3 B and 3 E, first and second wells 115 A and 115 B are formed in semiconductor layer 100 . First and second P-wells 115 A and 115 B are simultaneously formed, in one example, by photolithographically defining and then ion implanting selected regions of substrate 100 . In one example, first and second wells 115 A and 115 B are doped P-type. In FIGS. 3B and 3E , first and second wells 115 A and 115 B extends along the bottom surfaces of dielectric isolation 105 . Wells are not formed in FIG. 3C (where the photodiode will be subsequently formed) and FIG. 3D (where the floating diffusion node will be subsequently formed).
FIG. 4A is a top view and FIGS. 4B , 4 C, 4 D and 4 E are cross-sections through respective lines 4 B- 4 B, 4 C- 4 C, 4 D- 4 D and 4 E- 4 E of FIG. 4A illustrating continuing fabrication of a pixel sensor cell according to embodiments of the present invention. In FIGS. 4A , 4 B and 4 D, an optional electron shield 120 formed in semiconductor layer 100 . Electron shield 120 is formed, in one example, by photolithographically defining and then ion implanting selected regions of substrate 100 . In one example, electron shield 120 is doped P-type. In FIGS. 4B and 4E , electron shield 120 is a buried layer and does not extend to top surface 107 of semiconductor layer 100 , a region of semiconductor layer 100 above electron shield 120 intervening. Electron shield 120 extends along the bottom surfaces of dielectric isolation 105 . In FIG. 4D , (where the floating diffusion node will be subsequently formed) electron shield 120 abuts (i.e., abuts) dielectric passivation layer 110 and extend under dielectric passivation 105 . If dielectric passivation layer 110 is not present, electron shield 120 abuts dielectric isolation 105 .
FIG. 5A is a top view and FIGS. 5B , 5 C, 5 D and 5 E are cross-sections through respective lines 5 B- 5 B, 5 C- 5 C, 5 D- 5 D and 5 E- 5 E of FIG. 5A illustrating continuing fabrication of a pixel sensor cell according to embodiments of the present invention. In FIGS. 5A and 5B gate electrodes 125 , 130 , 135 , 140 and 145 are foamed. Bold lines illustrate perimeters of gate electrodes 125 , 130 , 135 , 140 and 145 . In one example, gate electrodes 125 , 130 , 135 , 140 and 145 may be simultaneously formed by depositing a gate dielectric layer, then a polysilicon layer on the gate dielectric later followed by photolithographically defining and then etching away unprotected (by the patterned photoresist layer) regions of the polysilicon layer.
FIG. 5F is a cross-section illustrating gate structures through line 5 B- 5 B of FIG. 5A . In FIG. 5F , gate dielectric layers 126 , 131 , 136 , 141 and 146 intervene between respective gate electrodes 125 , 130 , 135 , 140 and 145 and semiconductor layer 100 . There are five gate electrodes as the completed pixel sensor cell will be a five-transistor pixel sensor cell.
FIG. 6A is a top view and FIGS. 6B , 6 C, 6 D and 6 E are cross-sections through respective lines 6 B- 6 B, 6 C- 6 C, 6 D- 6 D and 6 E- 6 E of FIG. 6A illustrating continuing fabrication of a pixel sensor cell according to embodiments of the present invention. In FIGS. 6A , 6 B and 6 C, a photodiode body 150 is Rained in semiconductor layer 100 . Photodiode body 150 is formed, in one example, by photolithographically defining and then ion implanting selected regions of substrate 100 . In one example, photodiode body 150 is doped N-type. When photodiode body is N-type and semiconductor layer 100 is P-type, photodiode body 150 forms the cathode and semiconductor layer 100 forms the anode of the photodiode. In FIGS. 6B and 6C , photodiode body 150 does not extend as deep into semiconductor layer 100 as dielectric isolation and abuts dielectric passivation layer 110 . In FIGS. 6B and 6C , photodiode body 150 is a buried structure and does not extend to top surface 107 of semiconductor layer 100 , a region of semiconductor layer 100 above photodiode body 150 intervening. In FIG. 6C , photodiode body 150 abuts dielectric isolation passivation layer 110 . If dielectric isolation passivation layer 110 is not present, then photodiode body 150 abuts dielectric isolation 105 directly.
FIG. 7A is a top view and FIGS. 7B , 7 C, 7 D and 7 E are cross-sections through respective lines 7 B- 7 B, 7 C- 7 C, 7 D- 7 D and 7 E- 7 E of FIG. 7A illustrating continuing fabrication of a pixel sensor cell according to embodiments of the present invention. In FIGS. 7A , 7 B, 7 C and 7 D, an optional pinning layer 155 is formed in semiconductor layer 100 . Pinning layer 155 is formed, in one example, by photolithographically defining and then ion implanting selected regions of substrate 100 . In one example, pinning layer 155 is doped P-type. In FIGS. 7B and 7D , pinning layer 155 extends from top surface 107 of semiconductor layer 100 to photodiode body 150 . In FIG. 7D , (where the floating diffusion node will be subsequently formed) pinning layer 155 extends from top surface 107 of semiconductor layer 100 , toward but does not abut electron shield 120 if electron shield 120 is present. If electron shield 120 is present, a region of semiconductor layer intervenes 100 between pinning layer 155 and electron shield 120 . In FIG. 7D , pinning layer 155 abuts dielectric isolation 105 and overlaps opposite side of electron shield 120 . A region of top surface 107 of semiconductor layer 100 is exposed between regions of pinning layer 155 . In FIG. 7D , if dielectric passivation layer 110 is present, pinning layer 155 abuts dielectric passivation layer 105 .
FIG. 8A is a top view and FIGS. 8B , 8 C, 8 D and 8 E are cross-sections through respective lines 8 B- 8 B, 8 C- 8 C, 8 D- 8 D and 8 E- 8 E of FIG. 8A illustrating continuing fabrication of a pixel sensor cell according to embodiments of the present invention. In FIGS. 8A , 8 B and 8 E, source/drains 160 A, 160 B, 160 C and 160 D are formed in semiconductor layer 100 . Source/drains 160 A, 160 B, 160 C and 160 D are simultaneously formed, in one example, by photolithographically defining and then ion implanting selected regions of substrate 100 . In one example, source/drains 160 A, 160 B, 160 C and 160 D are doped N-type. In FIG. 8C (where the photodiode has been formed), FIG. 8D , where the floating diffusion node will be formed) first source/drains have not been formed. Source/drains 160 A, 160 B, 160 C and 160 D extend from top surface 107 of semiconductor layer 100 a distance that lees than the distance dielectric isolation extend into semiconductor layer 100 .
FIG. 9A is a top view and FIGS. 9B , 9 C, 9 D and 9 E are cross-sections through respective lines 9 B- 9 B, 9 C- 9 C, 9 D- 9 D and 9 E- 9 E of FIG. 9A illustrating continuing fabrication of a pixel sensor cell according to embodiments of the present invention. In FIGS. 9A , 9 B and 9 D, a floating diffusion node 165 is formed in semiconductor layer 100 . Floating diffusion node 165 is formed, in one example, by photolithographically defining and then ion implanting selected regions of substrate 100 . In one example, floating diffusion node 165 is doped N-type. In FIGS. 9B and 9D , floating diffusion node 165 extends from top surface 107 of semiconductor layer 100 into but not through electron shield 120 (if electron shield 120 is present). FIG. 9D illustrates the floating diffusion node (FD node) with all optional elements. It is a feature of the embodiments of the present invention that floating diffusion node 165 does not abut dielectric isolation 105 . It is a feature of the embodiments of the present invention that floating diffusion node 165 does not abut pinning layer 155 (if pinning layer 155 is present). It is a feature of the embodiments of the present invention that floating diffusion node 165 does not extend to dielectric isolation passivation layer 110 (if dielectric isolation passivation layer 110 is present). In FIG. 9D , a region of semiconductor layer 100 intervenes between floating diffusion node and dielectric isolation 105 and/or dielectric isolation passivation layer 110 and/or pinning layer 155 .
FIGS. 10A , 10 B, 10 C and 10 D illustrate alternative structures for the storage node of a pixel sensor cell according to embodiments of the present invention. FIGS. 10A , 10 B, 10 C and 10 D illustrate four possible combinations of the structural elements defining charge storage nodes according to the embodiments of the present invention.
In FIG. 10A , a first charge storage node 170 includes floating diffusion node 165 and semiconductor layer 100 . Floating diffusion node 165 does not abut dielectric isolation 105 , semiconductor layer 100 intervening between floating diffusion node 165 and dielectric isolation 105 . This is the minimum number of elements for a floating diffusion node according to embodiments of the present invention.
In FIG. 10B , a second charge storage node 175 includes floating diffusion node 165 , semiconductor layer 100 and electron shield 120 . Floating diffusion node 165 does not extend to dielectric isolation 105 , semiconductor layer 100 intervening between floating diffusion node 165 and dielectric isolation 105 . Electron shield 120 abuts dielectric isolation 105 . Electron shield 120 does not abut top surface 107 of semiconductor layer 100 , regions of semiconductor layer 100 intervening between electron shield 120 and top surface 107 of semiconductor layer 100 . Floating diffusion node 165 extends into semiconductor layer 100 but not to electron shield 120 , a region of semiconductor layer 100 intervening between floating diffusion node 165 and electron shield 120 . Alternatively, floating diffusion node 165 extends to electron shield 120 or extends part way into electron shield 120 .
In FIG. 10C , a third charge storage node 180 includes floating diffusion node 165 , semiconductor layer 100 , electron shield 120 , and dielectric isolation passivation layer 110 . Dielectric isolation passivation layer 110 abuts sidewalls and bottom surface of dielectric isolation 105 . Floating diffusion node 165 does not abut dielectric isolation passivation layer 110 , a region of semiconductor layer 100 intervening between floating diffusion node 165 and dielectric isolation passivation layer 110 . Electron shield 120 abuts dielectric isolation passivation layer 110 . Electron shield 120 does not abut top surface 107 of semiconductor layer 100 , regions of semiconductor layer 100 intervening between electron shield 120 and top surface 107 of semiconductor layer 100 . Floating diffusion node 165 extends into semiconductor layer 100 but not to electron shield 120 , a region of semiconductor layer 100 intervening between floating diffusion node 165 and electron shield 120 . Alternatively, floating diffusion node 165 extends to electron shield 120 or extends part way into electron shield 120 .
In FIG. 10D , a fourth charge storage node 185 includes floating diffusion node 165 , semiconductor layer 100 , electron shield 120 , dielectric isolation passivation layer 110 and pinning layer 155 . Dielectric isolation passivation layer 110 abuts sidewalls and a bottom surface of dielectric isolation 105 . Floating diffusion node 165 does not abut dielectric isolation passivation layer 110 , semiconductor layer 100 intervening between floating diffusion node 165 and dielectric isolation passivation layer 110 . Electron shield 120 abuts dielectric isolation passivation layer 110 . Electron shield 120 does not abut top surface 107 of semiconductor layer 100 , regions of semiconductor layer 100 intervening between electron shield 120 and top surface 107 of semiconductor layer 100 . Floating diffusion node 165 extends into semiconductor layer 100 from top surface 107 but not to electron shield 120 , a region of semiconductor layer 100 intervening between floating diffusion node 165 and electron shield 120 . Alternatively, floating diffusion node 165 extends to electron shield 120 or extends part way into electron shield 120 . Pinning layer 155 extends from top surface 107 into semiconductor layer 100 and along top surface 107 toward floating diffusion node 165 but does not abut floating diffusion node 165 , a region of semiconductor layer 100 intervening. Alternatively, pinning layer 155 extends to abut floating diffusion node 165 . Pinning layer 155 abuts dielectric isolation 105 , dielectric passivation layer 110 and regions of semiconductor layer 100 but not electron shield 120 . A region of semiconductor layer 100 intervenes between pinning layer 155 and electron shield 120 .
Other possible combinations for charge storage nodes according to embodiments of the present invention include floating diffusion node 165 with a region of semiconductor layer 100 intervening between floating diffusion node 165 and dielectric isolation 105 in combination with (i) only dielectric isolation passivation layer 110 , (ii) only dielectric isolation passivation layer 110 and pinning layer 155 , (iii) only pinning layer 155 , and (iv) only pinning layer 155 and electron shield 120 .
FIG. 11 is a top view of illustrating interconnections of the structural elements in a pixel sensor cell circuit. FIG. 11 is similar to FIG. 9 . In FIG. 11 , source/drain 160 A is connected to Vdd, gate 125 is connected to a global shutter signal (GS), gate 130 is connected to a transfer gate signal (TG), floating diffusion node 165 is connected to gate 140 , gate 135 is connected to a reset gate signal (RG), source/drain 160 B is connected to Vdd, gate 145 is connected to a row select signal (RS), and source/drain 160 D is connected to Data Out.
FIG. 12 is a circuit diagram of a pixel sensor cell circuit according to embodiments of the present invention. In FIG. 12 , circuit 200 describes device of FIG. 11 . Circuit 200 includes NFETs T 1 (reset transistor), T 2 (source follower), T 3 (row select transistor), T 4 (global shutter transistor) and T 5 (transfer gate), and photodiode D 1 (photon detector). The gate of NFET T 1 is connected to RG, the gate of NFET T 2 is connected to the floating diffusion node (FD Node), the gate of NFET T 3 is connected to RS, the gate of NFET T 4 is connected to GS and the gate of NFET T 5 is connected to TG. The drains of NFETS T 1 , T 2 and T 4 are connected to Vdd. The source of NFET T 1 is connected to the FD Node, the drain of NFET T 2 to the source of NFET T 3 and the source of NFET T 3 to Data Out. The source of NFET T 4 is connected to the source of NFET T 5 and the drain of NFET T 5 is connected to FD Node. The cathode of diode D 1 is connected to the sources of NFETS T 4 and T 5 and the anode of diode D 1 is connected to GND. Diode D 1 is the pinned photo diode of FIG. 11 .
Circuit 200 utilizes NFETs. However, NFETs T 1 , T 2 , T 3 , T 4 and T 5 can be replaced by PFETs. In a circuit utilizing PFETs, the doping type of elements of FIG. 11 are changed. Semiconductor layer 100 , dielectric passivation layer 110 , wells 115 A and 115 B, electron shield 120 and pinning layer 155 are doped N-type and photodiode body 150 , source/drains 160 A, 160 B, 160 C and 160 D and floating diffusion node 165 are doped P-type. Also Vdd and GND are reversed, and the anode of diode D 1 is connected to the now drains of now PFETS T 4 and T 5 .
FIG. 13 is a diagram illustrating an array of global shutter pixel sensor cells according to embodiments of the present invention. In FIG. 13 , an image sensor 300 includes an array 305 of pixel sensor cells P (rows are horizontal and columns vertical), pixel sensor cell drivers 3190 and a column sampler 315 . Each pixel sensor cell P is a circuit 200 of FIG. 11 . The GS, TG, RG, and RS signals of FIG. 12 are connected to pixel sensor cells P from pixel sensor cell row drivers 310 . The Data Out signals of FIG. 12 from pixel sensor cells P are connected to column sampler 315 .
In operation a global exposure is performed by (1) pulsing GS on/off (on=high for an NFET, off=low for an NFET) to charge the photodiode (exposure starts at off), (2) resetting FD Node by pulsing RG on/off, and (3) puling TG on/off to move the charge to FD Node. Readout is performed by (1) turning on RS to read all columns in a selected row and (2) pulsing RG on/off after reading the selected row. Readout steps (1) and (2) are repeated for each row sequentially, starting with the first row and ending with the last row.
FIG. 14 shows a block diagram of an exemplary design flow 400 used for example, in semiconductor IC logic design, simulation, test, layout, and manufacture. Design flow 400 includes processes and mechanisms for processing design structures or devices to generate logically or otherwise functionally equivalent representations of the design structures and/or devices described above and shown in FIGS. 9A , 9 B, 9 C, 9 D, 9 E, 10 A, 10 B, 10 C, 10 D, 11 , 12 and 13 . The design structures processed and/or generated by design flow 400 may be encoded on machine-readable transmission or storage media to include data and/or instructions that when performed or otherwise processed on a data processing system generate a logically, structurally, mechanically, or otherwise functionally equivalent representation of hardware components, circuits, devices, or systems. Design flow 400 may vary depending on the type of representation being designed. For example, a design flow 400 for building an application specific IC (ASIC) may differ from a design flow 400 for designing a standard component or from a design flow 400 for instantiating the design into a programmable array, for example a programmable gate array (PGA) or a field programmable gate array (FPGA).
FIG. 14 illustrates multiple such design structures including an input design structure 420 that is preferably processed by a design process 410 . In one embodiment, the design structure 420 comprises input design data used in a design process and comprising information describing an embodiment of the invention with respect to a CMOS imaging cell as shown in FIGS. 9A , 9 B, 9 C, 9 D, 9 E, 10 A, 10 B, 10 C, 10 D, 11 , 12 and 13 . The design data in the form of schematics or HDL, a hardware description language (e.g., Verilog, VHDL, C, etc.) may be embodied on one or more machine-readable media. For example, design structure 420 may be a text file, numerical data or a graphical representation of an embodiment of the invention as shown in FIGS. 9A , 9 B, 9 C, 9 D, 9 E, 10 A, 10 B, 10 C, 10 D, 11 , 12 and 13 . Design structure 420 may be a logical simulation design structure generated and processed by design process 410 to produce a logically equivalent functional representation of a hardware device. Design structure 420 may also or alternatively comprise data and/or program instructions that when processed by design process 410 , generate a functional representation of the physical structure of a hardware device. Whether representing functional and/or structural design features, design structure 420 may be generated using electronic computer-aided design (ECAD) such as implemented by a core developer/designer. When encoded on a machine-readable data transmission, gate array, or storage medium, design structure 420 may be accessed and processed by one or more hardware and/or software modules within design process 410 to simulate or otherwise functionally represent an electronic component, circuit, electronic or logic module, apparatus, device, or system such as those shown in FIGS. 9A , 9 B, 9 C, 9 D, 9 E, 10 A, 10 B, 10 C, 10 D, 11 , 12 and 13 . As such, design structure 420 may comprise files or other data structures including human and/or machine-readable source code, compiled structures, and computer-executable code structures that when processed by a design or simulation data processing system, functionally simulate or otherwise represent circuits or other levels of hardware logic design. Such data structures may include hardware description language (HDL) design entities or other data structures conforming to and/or compatible with lower-level HDL design languages such as Verilog and VHDL, and/or higher-level design languages such as C or C++.
Design process 410 preferably employs and incorporates hardware and/or software modules for synthesizing, translating, or otherwise processing a design/simulation functional equivalent of the components, circuits, devices, or logic structures shown in FIGS. 9A , 9 B, 9 C, 9 D, 9 E, 10 A, 10 B, 10 C, 10 D, 11 , 12 and 13 to generate a netlist 480 which may contain design structures such as design structure 420 . Netlist 480 may comprise, for example, compiled or otherwise processed data structures representing a list of wires, discrete components, logic gates, control circuits, I/O devices, models, etc. that describes the connections to other elements and circuits in an integrated circuit design. Netlist 480 may be synthesized using an iterative process in which netlist 480 is re-synthesized one or more times depending on design specifications and parameters for the device. As with other design structure types described herein, netlist 480 may be recorded on a machine-readable data storage medium or programmed into a programmable gate array. The medium may be a non-volatile storage medium such as a magnetic or optical disk drive, a programmable gate array, a compact flash, or other flash memory. Additionally, or in the alternative, the medium may be a system or cache memory, buffer space, or electrically or optically conductive devices and materials on which data packets may be transmitted and intermediately stored via the Internet, or other networking suitable means.
Design process 410 may include hardware and software modules for processing a variety of input data structure types including netlist 480 . Such data structure types may reside, for example, within library elements 430 and include a set of commonly used elements, circuits, and devices, including models, layouts, and symbolic representations, for a given manufacturing technology (e.g., different technology nodes, 32 nm, 45 nm, 90 nm, etc.). The data structure types may further include design specifications 440 , characterization data 450 , verification data 460 , design rules 470 , and test data files 485 which may include input test patterns, output test results, and other testing information. Design process 410 may further include, for example, standard mechanical design processes such as stress analysis, thermal analysis, mechanical event simulation, process simulation for operations such as casting, molding, and die press forming, etc. One of ordinary skill in the art of mechanical design can appreciate the extent of possible mechanical design tools and applications used in design process 410 without deviating from the scope and spirit of the invention. Design process 410 may also include modules for performing standard circuit design processes such as timing analysis, verification, design rule checking, place and route operations, etc.
Design process 410 employs and incorporates logic and physical design tools such as HDL compilers and simulation model build tools to process design structure 420 together with some or all of the depicted supporting data structures along with any additional mechanical design or data (if applicable), to generate a output design structure 490 comprising output design data embodied on a storage medium in a data format used for the exchange of layout data of integrated circuits and/or symbolic data format (e.g. information stored in a GDSII (GDS2), GL1, OASIS, map files, or any other suitable format for storing such design structures). In one embodiment, the second design data resides on a storage medium or programmable gate array in a data format used for the exchange of data of mechanical devices and structures (e.g. information stored in an IGES, DXF, Parasolid XT, JT, DRG, or any other suitable format for storing or rendering such mechanical design structures). Similar to design structure 420 , design structure 490 preferably comprises one or more files, data structures, or other computer-encoded data or instructions that reside on transmission or data storage media and that when processed by an ECAD system generate a logically or otherwise functionally equivalent form of one or more of the embodiments of the invention shown in FIGS. 9A , 9 B, 9 C, 9 D, 9 E, 10 A, 10 B, 10 C, 10 D, 11 , 12 and 13 . In one embodiment, design structure 490 may comprise a compiled, executable HDL simulation model that functionally simulates the devices shown in FIGS. 9A , 9 B, 9 C, 9 D, 9 E, 10 A, 10 B, 10 C, 10 D, 11 , 12 and 13 . Design structure 490 may also employ a data format used for the exchange of layout data of integrated circuits and/or symbolic data format (e.g. information stored in a GDSII (GDS2), GL1, OASIS, map files, or any other suitable format for storing such design data structures). Design structure 490 may comprise information such as, for example, symbolic data, map files, test data files, design content files, manufacturing data, layout parameters, wires, levels of metal, vias, shapes, data for routing through the manufacturing line, and any other data required by a manufacturer or other designer/developer to produce a device or structure as described above and shown in FIGS. 9A , 9 B, 9 C, 9 D, 9 E, 10 A, 10 B, 10 C, 10 D, 11 , 12 and 13 . Design structure 490 may then proceed to a stage 495 where, for example, design structure 490 proceeds to tape-out, is released to manufacturing, is released to a mask house, is sent to another design house, is sent back to the customer, etc.
The description of the embodiments of the present invention is given above for the understanding of the present invention. It will be understood that the invention is not limited to the particular embodiments described herein, but is capable of various modifications, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, it is intended that the following claims cover all such modifications and changes as fall within the true spirit and scope of the invention. | Pixel sensor cells, method of fabricating pixel sensor cells and design structure for pixel sensor cells. The pixel sensor cells including: a photodiode body in a first region of a semiconductor layer; a floating diffusion node in a second region of the semiconductor layer, a third region of the semiconductor layer between and abutting the first and second regions; and dielectric isolation in the semiconductor layer, the dielectric isolation surrounding the first, second and third regions, the dielectric isolation abutting the first, second and third regions and the photodiode body, the dielectric isolation not abutting the floating diffusion node, portions of the second region intervening between the dielectric isolation and the floating diffusion node. | 7 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to non load-bearing partitions used in buildings, and in particular, to panels and panel methods involving panels with multiple layers.
2 Description of Related Art
The building of interior walls and other non-load-bearing walls is fairly time-consuming. A traditional method is nailing wooden top plates and bottom plates to ceilings and floors, respectively, before nailing to them a number of spaced, parallel studs. Plumbing and electrical lines are then routed through holes drilled in the studs, headers, and footers. This arrangement can then be covered with sheetrock (gypsum drywall) with apertures that allow access to the plumbing and electrical lines as needed.
In some settings, the studs, headers, and footers may be steel framing members especially adapted for this purpose. The metal studs may have punched holes to provide chases for utility lines (plumbing and electrical). Again, sheetrock can be installed over the metal studs with apertures to allow access to plumbing and electrical lines as needed.
These types of walls and partitions easily transmit sound. For this reason builders may install sound deadening material inside the wall or place such material on one of the surfaces of the wall.
Boards made from a magnesium oxide mineral (MgO boards) are sometimes used instead of sheetrock, and are sometimes used in exterior applications. MgO boards are fairly waterproof, fire resistant, and resistant to mold, fungus, and insects.
Structural insulated panels (SIPs) are commercially available and typically employ an insulating foam core sandwiched between facings made of oriented strand board (OSB).
See also U.S. Pat. Nos. 4,559,263; 4,572,857; 5,104,715; 5,351,454; 5,792,552; and 6,599,621; as well as US Patent Application Publication Nos. 2011/0268916; and 2015/0052838.
SUMMARY OF THE INVENTION
In accordance with the illustrative embodiments demonstrating features and advantages of the present invention, there is provided a panel including an insulating barrier having an opposing pair of sides. The insulating barrier includes a first stratum and a second stratum having a first plurality of ridges and a second plurality of ridges, respectively. The first and the second plurality of ridges face each other. The first plurality of ridges runs athwart the second plurality of ridges. One or more adjacent pairs of the first plurality of ridges have between them clearance providing a mechanical chase across at least most of the panel. The panel also includes a cladding overlaying the insulating barrier on at least one of the opposing pair of sides. The cladding has a density exceeding that of the first and the second stratum
In accordance with another aspect of the invention, a method is provided for utilizing a panel to be fabricated from a first material and a second material. The method includes the step of forming from the first material a pair of strata each having a plurality of ridges. Another step is attaching the plurality of ridges of one of the pair of strata to the plurality of ridges of the other one of the pair of strata, with the plurality of ridges of one of the pair of strata transverse to the plurality of ridges of the other one of the pair of strata. The method also includes the step of externally cladding the pair of strata using the second material.
In accordance with yet another aspect of the invention, a method is provided for installing a utility feed in a cladded panel having a central pair of strata each with parallel grooves. The grooves of one of the pair of strata being opposed and transverse to the grooves of the other one of the pair of strata. The method includes several steps, performed in any order. One step is mounting the cladded panel in a building structure. Another step is routing the utility feed along one of the grooves of one of the pair of strata.
By employing apparatus and methods of the foregoing type an improved panel and panel techniques are achieved. In some embodiments, a foam insulating barrier is cladded on opposite sides by a denser material, for example, MgO boards, sheet metal, vinyl, sheetrock, etc. The cladding can be held in place by adhesives, or by other means.
A disclosed foam insulating barrier is formed of two strata, each with a plurality of spaced, parallel ridges. The ridges of one stratum faces and is perpendicular to the ridges of the other stratum. The ridges of the two strata can be attached together by adhesives or by other means.
The disclosed panel can be installed inside a building without the need for conventional framing (studs, and plates). This panel can be installed using U-shaped, metal tracks on the top and bottom of the panel. The disclosed bottom track can be nailed, screwed, or adhesively secured in place before sliding the panel into the track. The disclosed upper track can be similarly installed and the disclosed embodiment may or may not have an outwardly projecting tab with a fastener hole. This upper track can be positioned atop the panel before securing the track. The panel itself can be held in place with fasteners or by adhesive means.
The clearance between adjacent ridges of each of the two strata provides a groove that can be used as a mechanical chase for utility feeds such as plumbing or electrical wiring. Because the ridges of the two strata are transverse, the utility feeds can be routed either vertically or horizontally, depending on which grooves of the two strata are utilized.
Panels of this type will also have a degree of soundproofing or sound deadening qualities. The foam core by itself has some acoustical attenuating properties. In addition, the transverse ridges of the opposing foam strata reduces the surface contact between the strata to a number of relatively small points, thereby greatly reducing the ability of sound to travel from one stratum to the other.
BRIEF DESCRIPTION OF THE DRAWINGS
The above brief description as well as other objects, features and advantages of the present invention will be more fully appreciated by reference to the following detailed description of illustrative embodiments in accordance with the present invention when taken in conjunction with the accompanying drawings, wherein:
FIG. 1 is an exploded, perspective view of a panel in accordance with principles of the present invention;
FIG. 2 is a cross-sectional view of the panel of FIG. 1 , shown assembled;
FIG. 3 is a perspective view of a panel of that is dimensioned differently than that of FIG. 1 , and is shown assembled, and with portions broken away for illustrative purposes;
FIGS. 4A-4C are end views showing steps in forming and assembling components that can be used to make panels similar to that of FIG. 2 ;
FIGS. 5A-5C are end views showing steps in forming and assembling components of a panel that is an alternate to that of FIG. 2 ;
FIG. 6 is an end view of components that are an alternate to that of FIG. 4A ;
FIG. 7 is a perspective view of tracks used to install one of the panels of FIGS. 1-6 , with the panel shown in phantom and with portions broken away for illustrative purposes; and
FIG. 8 is a perspective view of the panel of FIG. 3 with portions broken away for illustrative purposes, and with various utility feeds installed and with a spline being installed.
DETAILED DESCRIPTION
Referring to FIGS. 1 and 2 , the constituent components of panel 10 are shown as rectangular external layers 16 and 18 , and internal strata 12 and 14 (these strata are also referred to as the first and second stratum). Layers 16 and 18 (each layer also referred to as cladding) may be MgO board (board made with a mineral based material, namely magnesium oxide). Instead of MgO board, some embodiments may use gypsum wallboard, cementitious board, sheet metal, plywood, other wood composites such as OSB, etc Some embodiments will use mass-loaded vinyl for sound proofing purposes.
When used, the gypsum wallboard may be plain with paint or fabric or vinyl finishes. When used, the sheet metal may be of various gauges with any of a variety of coatings and finishes. In some embodiments layer 16 can be made of different material than layer 18 , e g. wallboard on one side and MgO board on the other. In still other embodiments, one of the layers 16 or 18 can be eliminated.
In this embodiment the height and width of components 12 , 14 , 16 , and 18 are the same, i.e. they have a square outline. It will be appreciated that outlines with proportions other than a square outline will be more prevalent.
Strata 14 and 16 (referred to collectively as an insulating barrier) are fabricated from a rigid foam material made from substances such as polyurethane, polyisocyanurate, polystyrene, EPS (expanded polystyrene), etc. A variety of other materials are feasible, and good results are achieved when external layers 16 and 18 are denser than strata 12 and 14 . Strata 12 and 14 may be fabricated by extrusion, molding, or other fabrication processes.
The inside face of strata 14 is corrugated and has a plurality of parallel ridges 14 A, in this embodiment nine such ridges. Eight grooves 14 B are interleaved with ridges 14 A Except for the outermost ridges, ridges 14 A have a common polygonal cross-section; namely, a symmetrical trapezoidal shape with slanted sides converging to a flat top. The two outermost of the ridges 14 A are truncated; that is, their cross-sections are halved along a longitudinally disposed plane that is transverse to layers 16 and 18 .
Since panel 10 has a square outline, stratum 12 may be identical to stratum 14 . Therefore, stratum 12 will also have nine ridges 12 A with eight grooves 12 B between them. However, ridges 12 A have been rotated 90° and are therefore transverse to ridges 14 A. Thus in FIG. 1 ridges 12 A are vertical, while ridges 14 A are horizontal.
Using this orientation, strata 12 and 14 are cemented together as shown in FIG. 2 . Basically, the nine ridges 12 A will have 81 intersections with the nine ridges 14 A. Ridges 12 A and 14 A may be secured together at these intersections with structural adhesives, and general purpose adhesives such as a polyurethane adhesive, cyanoacrylate adhesive, epoxy, polyisocyanurate adhesive, etc.
In this embodiment, the tops of ridges 12 A and 14 A, and the floors of grooves 12 B and 14 B will each be 1⅞″ (4.76 cm) wide. The height of ridges 12 A and 14 A (and thus the depth of grooves 12 B and 14 B) will each be 1⅛″ (2.86 cm). With these dimensions, the ridge to ridge spacing will be 4 inches (10 cm). The overall thickness of strata 12 and 14 is 2¾″ (7 cm) and thus when stacked transversely, the overall thickness of the stack is 5½″ (14 cm). This thickness is comparable to the larger dimension of a 2×6 stud (whose nominal dimension is actually 5½″ or 14 cm).
It will be appreciated that these ridges 12 A and 14 A and grooves 12 B and 14 B may have different dimensions and different shapes in other embodiments.
Cladding 16 and 18 can be secured to the outsides of strata 12 and 14 , respectively, by adhesives similar to those used to secure the strata together. Thus, the four components of panel 10 are permanently secured together and can be sold as a single, rigid unit.
Referring to FIG. 3 , panel 110 is approximately 4′×8′ (1.2 m×2.4 m) and is longer than the previously illustrated panel, which was approximately a 4 foot square (1.2 m square). In some cases panel 110 will be 4 feet×10 feet (1.2 m×3 m), or 4 feet by 12 feet (1.2 m×3.7 m). Components in this Figure corresponding to those of FIG. 1 have the same reference numerals but increased by 100.
In this embodiment, stratum 114 has the same cross-section as previously mentioned stratum 14 , but is twice as long, i.e. 8 feet long (2.4 m long). Stratum 112 is twice as wide and therefor has a greater number of ridges 112 A. While one can create stratum 112 by butting together two of the previously mentioned strata (strata 12 of FIG. 1 ), better structural integrity will be achieved by fabricating stratum 112 as a single molded or extruded unit. Note that the number of ridges 112 does not precisely double because at the midline two smaller (halved) ridges form one ridge to create a total of seventeen ridges.
FIGS. 4A-4C describe a technique for making strata 212 and 214 . In FIG. 4A strata 212 and 214 are shown as complementary slabs that can be separated to form ridges 212 A and 214 A, respectively. This separation can be achieved by passing a single rectangular slab through a corrugated blade that will cut the ridges 212 A and 214 A Alternatively, strata 212 and 214 can be separately fabricated by extrusion, cutting, or molding. In either case, two separate strata are achieved as shown in FIG. 4B .
In FIG. 4C stratum 214 has been rotated 90° relative to strata 212 to form an insulating barrier that can serve as a foam core for a panel of the type previously described.
The foregoing assumes a square panel, but this technique can be employed to create panels with different proportions. For example, for a 4′×8′ panel, one would double the width of the profile shown in FIG. 4A , effectively doubling the number of ridges 214 A One would then split one stratum (e.g. stratum 214 ) in half longitudinally (parallel to the ridges), and split the other stratum (e.g. stratum 212 ) in half transversely (perpendicular to the ridges). Then each of the longitudinally split strata would be paired with of one the transversely split strata, with their respective ridges rotated 90° as before.
For a 4′×12′ panel, the profile of FIG. 4A would be tripled. Then, one stratum would be split longitudinally into three parts, while the other stratum would be split transversely into three parts. For a 4′×10′ panel a similar splitting can be used (quintupling and then splitting one stratum into a 5×2 matrix, and the other stratum into a 2×5 matrix).
FIG. 4C shows the rotated strata secured together to produce an insulating barrier that is 5½″ thick (14 cm thick). This thickness is consistent with a 2×6 stud.
In the embodiment of FIGS. 5A-5C , strata 312 and 314 have been scaled down, and have the same reference numerals but increased by 100.
Basically, when strata 312 and 314 have been rotated 90° and secured together as shown in FIG. 5C the overall thickness is 3½″, which is consistent with a 2×4 stud (whose larger dimension is actually 3½ inches, or 9 centimeters). In this embodiment ridges 312 A and 314 A, and grooves 312 B and 314 B have the same width and pitch as before, but now have a height and depth of 1⅛″ (2.8 cm).
Referring to FIG. 6 , this embodiment is much like that of FIG. 4 , and components corresponding thereto have the same reference numeral but increased by 200. In FIG. 6 the cross sections of ridges 412 A and 414 A are no longer polygonal but have curved sides. This sinuous profile is essentially a sinusoid with clipped amplitudes.
Referring to FIG. 7 previously mentioned panel 110 is shown installed inside a building in tracks 20 and 26 . Track 20 is a U-shaped channel with parallel walls 20 A and 20 B interconnected by web 20 C. Track 20 is sized to embrace the lower edge of panel 110 on the outside, or with its up-standing walls 20 A and 20 B inserted between the core components (core 12 . 14 of FIG. 1 ) and the skin components (skin components 16 and 18 of FIG. 1 ).
Web 20 C has a fastener hole 22 and nail 24 is shown about to be driven through that hole into the floor or floor joists, although in some cases a screw or other fastener can be used instead of a nail. In some cases the fastener 24 is driven through the center of the track 20 with the panel 110 being inserted afterwards. Walls 20 A and 20 B each have a fastener hole 34 . Screw 36 is shown about to be driven through the hole 34 in wall 20 A to hold panel 110 in place, although a nail or fastener can be used instead.
Upper track 26 is also shown as a U-shaped channel having a parallel pair of walls 26 A and 26 B interconnected by web 26 C. A tab 28 is punched out of the middle of wall 26 A, and is coplanar with web 26 C. Fastener holes 38 A and 38 B are formed in wall 26 A on opposite sides of tab 26 A. Screw 40 is shown about to be driven through hole 38 B to secure panel 110 in place (although a nail can be used instead of screw 40 ).
Tab 28 has a fastener hole 30 , and nail 32 is shown about to be driven through this hole to secure track 26 to the ceiling rafters or joists. Again, a screw or other fastener can be used instead of a nail.
While a single, relatively short track 20 is shown along the bottom of panel 110 , in many cases multiple sections of tracks will be used to hold the panel more securely. Alternatively, track 20 can be made relatively long with a number of fastener holes to hold panel 110 securely. Likewise, a number of track sections identical to track 26 can be installed across the top of panel 110 , or the track can be lengthened and provided with a number of fastener holes.
Instead of, or in addition, the foregoing fasteners, the installation may be performed with non-hardening acoustical sealant or foam tape. In some embodiments this sealant or tape can be used on opposite sides of web 20 C to secure the web to the floor and to panel 110 . Such sealant or tape can also be used to secure track 26 to the ceiling, in which case the track 26 need not be manufactured with fastening tab 28 , and can instead be a simple U-shaped channel, identical to channel 20 .
Referring to FIG. 8 , panel 110 has been installed as previously described in connection with FIG. 7 . As part of this installation, one of the horizontal grooves 1148 is being used as a mechanical chase, through which pipe P is routed. Pipe P may be part of a plumbing arrangement, for example, a water utility feed. In other cases pipe P may be a metal conduit through which electrical wires are routed. In still other cases pipe P may carry natural gas for a stove, dryer, furnace, etc. In still other cases, pipe P may constitute electrical wiring, telephone lines, cable television lines, etc
As previously described, stratum 112 has a number of vertical grooves (grooves 1128 of FIG. 3 ), and routed through one of those grooves is a conduit C. Conduit C is a drain to a sanitary sewer, although in some cases the conduit may be a vent, a water feed line, a natural gas line, electrical wiring, telephone lines, cable television lines, etc. Because the grooves in strata 112 and 114 do not overlap, separate elements can cross over each other inside panel 110 in the vertical and horizontal directions.
Electrical wiring W is routed through another one of the grooves 1146 in stratum 114 . This wiring W emerges through a hole 34 cut through stratum 112 to provide access to groove 114 B. Hole 34 can be cut either before or after panel 110 is installed in place. An electrical outlet may be installed in hole 34 in the usual fashion, although this method may be used for installing an electrical switch or other electrical devices.
In this embodiment, an installer wishes to install a second identical panel (i.e., a complementary member), edge to edge with panel 110 . For this reason, spline 36 is shown about to be inserted into one of the grooves 114 B. Spline 36 has a matching cross-section, that is, a trapezoidal cross-section. Spline 36 will be inserted halfway into groove 114 B and may be held in place by a fastener (not shown) driven through stratum 112 or 114 into the spline. In some cases an adhesive may be used instead of a fastener. Next, a second panel similar to panel 110 will be slid into position such that the exposed portion of spline 36 will slide into a matching groove in the incoming panel. Spline 36 may be secured in the second panel via fasteners or adhesives.
As a practical matter, utility feeds P and W will be installed after the second panel is in place, so that these feeds may be simultaneously routed through both panels.
While one spline 36 is illustrated, in some embodiments multiple splines may be used at the vertical joint between adjoining panels.
Panels of the foregoing type have numerous advantages. The panels have inherent rigidity and structural strength so that they can be readily used in a building, particularly for non-load-bearing, internal walls or walls that do not constitute the support structure of the building. As just described, installation can proceed without the need for conventional framing (studs, and top and bottom plates).
Also, the panel has intrinsic mechanical chases that facilitate the installation of utility feeds (plumbing, electrical, gas, telephone, etc.), as well as drains and vents. In addition the panel can be made with materials that are inherently waterproof, fire resistant, and resistant to mold, fungus and insects. Also, the foam core and the air trapped between the foam strata provide good thermal insulating properties.
The panels will also have a degree of soundproofing or sound deadening qualities. The above described foam core by itself has some acoustical attenuating properties. In addition, the transverse ridges of the opposing strata reduce the surface contact between the strata to a number of small points, thereby greatly reducing the ability of sound to travel from one stratum to the other. Furthermore, securing the panel with non-hardening acoustical sealant, gaskets, or foam tape avoids transmitting sound between rooms separated by the ceiling or floor, into the panel.
It is appreciated that various modifications may be implemented with respect to the above described embodiments. Instead of tracks, the panels may be installed against existing vertical structure in a building, e.g., on the inside of an exterior wall. Also, the panels can be installed in tracks built into a building structure and covered with molding. Also, panels may be stacked and secured in place as a stack to enhance rigidity, soundproofing, etc. In some cases the panels may be mounted in a horizontal plane. Panels may also be used as part of a cabinet, built-in shelf, or other architectural feature. In some embodiments, the panel may be sealed and used for outside applications.
Obviously, many modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described. | The insulating barrier of a panel including has a first stratum and a second stratum, each having a plurality of ridges that face each other, and run athwart of each other. Clearance between at least some adjacent pairs of the ridges provide a mechanical chase that reaches across at least most of the panel. A cladding overlaying at least one side of the insulating barrier is denser than the barrier. The mechanical chase is in the form of a groove through which a utility feed can be routed when the panel is to be mounted in a building. | 4 |
FIELD OF THE INVENTION
The present invention relates to a novel construction of a boiler, or similar heat exchanger, for heating water while cooling hot gases which are the products of combustion.
BACKGROUND OF THE INVENTION
Numerous designs exist in connection with this type of boiler: see, for example, Canadian Patent No. 1,182,698 to Cooke as well as 2,032,711 also to Cooke. However, these constructions, which mainly consist of upper and lower manifolds between which a plurality of serpentine liquid carrying tubes are mounted, do not permit the hot gases to pass laterally from passage to passage, the gases only rise.
OBJECTS AND STATEMENT OF THE INVENTION
It is an object of the present invention to provide a boiler which is simple to construct, to assemble and to operate, which is highly efficient and capable of handling varying loads, and which is suitable for use on a large scale, as in large buildings, industrial electric and co-generation plants as well as in relatively small residential installations.
These objects are achieved by providing a boiler in accordance with the present invention which comprises a housing having a top provided with a gas outlet, which can be positioned either at the front or the rear of the housing to suit individual site conditions, a bottom, left and right sides, and a front and back. Within the housing, an upper manifold and lower manifold extend substantially parallel to the top, bottom and side walls; between these two manifolds, two sets of tubes are displayed. Each set of tubes are identical the tubes being bent serpentinely so as to form a plurality of superimposed gas passages; at least two tubes of each set are bent differently so as to form access openings to the passages above below and adjacent.
The bends of the serpentine tubes are substantially in contact so they close the lowermost chamber and the gas passages within the housing. The gas passages are closed on the sides by removable closing plates. One set of tubes joins the upper left side of the upper manifold to the lower left side of the lower manifold while the other set of tubes joins the upper right side of the upper manifold to the lower right side of the lower manifold. The openings from passage to passage are offset so as to require a gas flowing through said passages to traverse one passage from front to back and the next passage from back to front. Means are provided for introducing liquid into the lower manifold and for withdrawing the liquid from the upper manifold; means are also provided for introducing a combustion gas into the lowermost of the superimposed passages. The combustion gases rise successively through the passages which they successively and alternately traverse from front to back and, then, from back to front, until they exit from the uppermost chamber through the gas outlet at the top, liquid flowing through the manifolds and tubes being heated by the combustion gases.
Advantageously, the tubes of each set are in substantial contact with one another so as to substantially prevent passage of combustion gas therebetween. In a preferred embodiment, there is provided a damper at the front of the passage above the lowermost passage so the furnace pressure can be controlled in conjunction with the amount of products of combustion being produced.
It is an object of the present invention to provide a boiler built with identical serpentine tubes on each side and a passage separator to increase the path of the hot gases to optimize heat exchange.
The boiler can be constructed lower in height and is less expensive to manufacture than the prior art.
In one form of the boiler, the gases in the gas passages above the furnace, or lowermost chamber, flow from above the rear to the front of the boiler and exit at the front.
The simple addition of an insulating board along the top of the uppermost tubes where the tubes connect to the upper manifold will redirect the gases to either the front or the rear of the boiler to exit to the atmosphere through the gas outlet.
To provide for expansion and contraction of the metal of the serpentine tubes, the boiler may be brought from a cold condition to full operating temperature in about ten minutes. The boiler can operate with a temperature differential of 150 degrees Fahrenheit between the inlet and outlet. Also, the boiler can be cooled rapidly for examination and or repairs without sustaining any permanent structural damage.
The boiler can be easily field assembled without welding in existing buildings through existing doorways, thus eliminating costly general contract work.
The boiler meets all of the requirements of the American Society of Mechanical Engineers boiler and pressure vessels, sections I and IV, which are recognized by agencies of most governments. The novel boiler incorporates the best features of the fire boiler by controlling the passage of hot gases and, by confining the water within small tubes, takes advantage of the best features of the water tube boiler.
All internal parts and surfaces are easily accessible for service and cleaning so the unit is suitable for burning light oil, residual oils, crude oils, waste oils, and type of gas, and any type of coal or solid fuel, including municipal waste.
Other objects and further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. It should be understood, however, that this detailed description while indicating preferred embodiments of the invention, is given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be further described with reference to the accompanying drawings, wherein:
FIG. 1 is a perspective view of a boiler of the invention with the housing shown in phantom. The differently bent tubes that form the access opening are not shown for clarity.
FIG. 2 is a right side view of the boiler and housing and the gas exit at the front of the boiler.
FIG. 3 is a left side view of the boiler in all configurations.
FIG. 4 is section at B--B of FIG. 2 and FIG. 11 showing the serpentine and straight tubes and the manifolds.
FIG. 5 is a front view of FIG. 2 showing the differently bent tubes that form the access opening to permit the gases to flow from one gas passage to next.
FIG. 6 is a rear view of FIG. 3 showing the differently bent tubes that form the access opening to permit the gases to flow from one gas passage to the next.
FIG. 7 is a right side view of the boiler and housing with a single gas pass through the furnace or lowermost passage, with an insulating board redirecting the gas to exit at the rear of the boiler.
FIG. 8 is a section at B--B of FIG. 7 and FIG. 14 showing the serpentine and straight tubes, the manifolds and the insulating board which redirects the gases.
FIG. 9 is a front view of FIG. 7 showing the differently bent tubes that form the access opening to permit the gases to flow from one gas passage to the next with the insulating board which redirects the gases.
FIG. 10 is a rear view of FIG. 7 showing the differently bent tubes that form the access opening to permit the gases to flow from one gas passage to the next with the insulating board which redirects the gases.
FIG. 11 is a perspective view of a boiler showing the path of the hot gases.
FIG. 12 is a detail of the furnace control damper.
DESCRIPTION OF PREFERRED EMBODIMENTS
Referring more particularly to FIGS. 1 and 2, there is shown a housing 20 having a top wall 21, opposite side walls 22, a front wall 23, a rear wall 24, a base 25, and a gas outlet 41 at the front. There are also provided an upper manifold 26, a lower manifold 27, a connection 28 for introducing liquid into the lower manifold, a connection 29 for withdrawing heated liquid or steam from the upper manifold, liquid return connection 30 at the bottom of the upper manifold to the top of the lower manifold: serpentine tubes 32 which form the gas passages, serpentine tubes 33 which form the access openings from gas passage to gas passage at the front, and serpentine tubes 36 which form the access openings from gas passage at the rear gas outlet 41 is shown.
FIG. 3 there is shown a housing 20 having a top wall 21, opposite side walls 22, a front wall 23, a rear wall 24, a base 25, and a gas outlet 41 at the front. There are also provided an upper manifold 26, a lower manifold 27, a connection 28 for introducing liquid into the lower manifold, a connection 29 for withdrawing heated liquid or steam from the upper manifold, liquid return connection 30 at the bottom of the upper manifold to the top of the lower manifold: serpentine tubes 31 which form the gas passages, tubes 34 which form the access openings from gas passage to gas passage at the front and serpentine tubes 36 which form the access openings from gas passage at the rear outlet 41 as shown.
FIG. 4 is a section common to all boilers of FIG. 2 and 11 and shows top wall 21, side walls 22 and base 25. It shows the formation of gas passages with serpentine tubes 31 and passage isolator 42.
FIG. 5 is a front view of FIG. 2 showing top wall 21, side walls 22, and base 25. It shows the serpentine tubes that are bent differently to form the access openings that allow the gases to flow from one gas passage to the next, 33 and 34, the serpentine tubes 31 are shown, upper manifold 26, lower 27, connection for withdrawing liquid or steam from the upper manifold 29 removable gas passage closing plate 40 and passage isolator 42.
FIG. 6 is a rear view of FIG. 2 showing top wall 21, side walls 22, and base 25. It shows the serpentine tubes that are bent differently to form the access openings that allow the gases to flow from one gas passage to the next, 35 and 36, serpentine tubes 31 are shown, upper manifold 26, lower manifold 27, removable gas passage closing plate 40 and passage isolator 42.
FIG. 7 shows a housing 20 having a top wall 21, two side walls 22, a front wall 23, a rear wall 24, a base 25 and a gas outlet 41 at the front. An upper manifold 26, a lower manifold 27, a connection 28 for introducing liquid into the lower manifold, a connection 29 for withdrawing heated liquid or steam from the upper manifold, liquid return connection 30 at the bottom of the upper manifold to the top of the lower manifold.
Serpentine tubes 31 which form the gas passages, and serpentine tubes 34 which form the access openings from gas passage to gas passage at the front and serpentine tubes 36 which form the access openings from gas passage to gas passage at the rear, and an insulating board 37 that redirects the gases to the front of the boiler.
FIG. 8 is a section common to the boilers of FIG. 7 with top wall 21, side walls 22 and base 25. It shows the formation of gas passages with serpentine tubes 31 and the gas passage closing plate 40. It shows the upper manifold 26 and the lower manifold 27, the insulating board 37 that redirects the gases, and gas passage isolator 42.
FIG. 9 is a front view of FIG. 7 showing top wall 21, side walls 22, and base 25. It shows the serpentine tubes that are bent differently to form the access openings that allow the gases to flow from one gas passage to the next, 33 and 341 the serpentine tubes 31 are shown upper manifold 26, lower manifold 27, connection 29 for withdrawing liquid or steam from the upper manifold, removable gas passage closing plate 40, and the insulating board 37 that redirects the gases and gas passage isolator 42.
FIG. 10 is a rear view of FIG. 7 showing the housing 20 with a top wall 21, side walls 22, base 25. It shows the serpentine tubes that are bent differently to form the access openings that allow the gases to flow from one gas passage to the next, 35 and 36, serpentine tubes 31 and gas passage isolator 42 upper manifold 26, lower manifold 27, removable gas passage closing plate 40 and the insulating board 37 that redirects the gases.
The novel boiler offers advantages with regard to nitrogen oxides (NOX) discharges as well. The NOX generation can be held to a minimum if combustion is under steady load and ideal conditions are established.
However, when the load fluctuates, there is a serious problem. In accordance with the present invention, the radiation section, i.e. the burner, is controlled independently of the convection section, i.e. the heat exchanger. Specifically, if less steam is required, so less fuel is burned; it is merely necessary to synchronize a motorized damper at the front of the gas passage immediately above the lowermost passage.
With the burner firing rate controlled so that, as the firing rate reduces, the damper will close and, as the firing rate increases, the damper will open, thereby maintaining the furnace chamber at a constant pressure.
The tubes, drums and manifolds may be formed of conventional boiler materials such as iron, steel, etc., and the boiler surfaces may be lined with refractory material, as desired.
The boiler shown in the drawings has four chambers above the combustion chamber; but, by appropriate bending of the tubes, the number could be one to ten, or more.
The number of tubes can also be varied; but, one suitable installation has the following parameters:
(1) Upper manifold - 20" dia×162"
(2) Lower manifold - 12" dia×152"
(3) Tube diameters - 1 1/2" inches
(4) Number of tubes per side - 61
(5) Total number of passages - 5
Certain advantages of the system have already been noted but there are many more. Specifically, the novel construction has the following advantages:
(a) the ability to independently control the combustion chamber pressures at all firing rates makes the burning of any fuel more efficient and easier;
(b) the boiler can be efficiently fired with gas, oil or coal by pulverized burner, wood or any solid combustible fuel or even municipal waste;
(c) the boiler gas passages are easily cleaned either manually or automatically;
(d) the boiler is suitable for exhaust gas utilization;
(e) the boiler meets the requirements of the ASME steam boiler construction code, Section 1, for low and high pressure steam, low and high temperature hot water, hot mineral oils and black liquor. The entrance of tubes into the manifolds allows large ligaments between the tube holes. This results in the boiler drums being as little as only 30 per cent of the thickness that is required in traditional boilers. This also allows the tubes to be attached to the drums by a drive morse taper rather than expanding the tube ends into the manifolds, which reduces labour costs in production and/or field assembly;
(f) the boiler does not require external draft controls of any kind;
(g) the boiler pressure vessel forms a perfect rectangular cube with water cooled sides and thus eliminates the need for expensive refractories and insulation; and
(h) the boiler tubes provide free expansion and contraction in all areas.
It will be appreciated that the instant disclosure and examples are set forth by way of illustration only and that various modification and changes may be made without departing from the spirit and scope of the present invention. | A highly efficient boiler made up of a housing containing upper and lower manifolds. Identical tubes connect the manifolds on the right and left sides to form a plurality of superimposed passages which the combustion gases must successively traverse laterally front to back and upwardly back to front. | 8 |
RELATED APPLICATION DATA
[0001] This application is a continuation of U.S. application Ser. No. 14/319,100, filed on Jun. 30, 2014 which is a continuation of PCT application no. PCT/US2013/075317, designating the United States and filed Dec. 16, 2013; which claims priority to U.S. Provisional Application No. 61/779,169, filed on Mar. 13, 2013 and U.S. Provisional Application No. 61/738,355, filed on Dec. 17, 2012 each of which is hereby incorporated herein by reference in their entirety for all purposes.
STATEMENT OF GOVERNMENT INTERESTS
[0002] This invention was made with government support under P50 HG005550 awarded by National Institutes of Health. The government has certain rights in the invention.
BACKGROUND
[0003] Bacterial and archaeal CRISPR systems rely on crRNAs in complex with Cas proteins to direct degradation of complementary sequences present within invading viral and plasmid DNA (1-3). A recent in vitro reconstitution of the S. pyogenes type II CRISPR system demonstrated that crRNA fused to a normally trans-encoded tracrRNA is sufficient to direct Cas9 protein to sequence-specifically cleave target DNA sequences matching the crRNA (4).
SUMMARY
[0004] The present disclosure references documents numerically which are listed at the end of the present disclosure. The document corresponding to the number is incorporated by reference into the specification as a supporting reference corresponding to the number as if fully cited.
[0005] According to one aspect of the present disclosure, a eukaryotic cell is transfected with a two component system including RNA complementary to genomic DNA and an enzyme that interacts with the RNA. The RNA and the enzyme are expressed by the cell. The RNA of the RNA/enzyme complex then binds to complementary genomic DNA. The enzyme then performs a function, such as cleavage of the genomic DNA. The RNA includes between about 10 nucleotides to about 250 nucleotides. The RNA includes between about 20 nucleotides to about 100 nucleotides. According to certain aspects, the enzyme may perform any desired function in a site specific manner for which the enzyme has been engineered. According to one aspect, the eukaryotic cell is a yeast cell, plant cell or mammalian cell. According to one aspect, the enzyme cleaves genomic sequences targeted by RNA sequences (see references (4-6)), thereby creating a genomically altered eukaryotic cell.
[0006] According to one aspect, the present disclosure provides a method of genetically altering a human cell by including a nucleic acid encoding an RNA complementary to genomic DNA into the genome of the cell and a nucleic acid encoding an enzyme that performs a desired function on genomic DNA into the genome of the cell. According to one aspect, the RNA and the enzyme are expressed, According to one aspect, the RNA hybridizes with complementary genomic DNA. According to one aspect, the enzyme is activated to perform a desired function, such as cleavage, in a site specific manner when the RNA is hybridized to the complementary genomic DNA. According to one aspect, the RNA and the enzyme are components of a bacterial Type II CRISPR system.
[0007] According to one aspect, a method of altering a eukaryotic cell is providing including transfecting the eukaryotic cell with a nucleic acid encoding RNA complementary to genomic DNA of the eukaryotic cell, transfecting the eukaryotic cell with a nucleic acid encoding an enzyme that interacts with the RNA and cleaves the genomic DNA in a site specific manner, wherein the cell expresses the RNA and the enzyme, the RNA binds to complementary genomic DNA and the enzyme cleaves the genomic DNA in a site specific manner. According to one aspect, the enzyme is Cas9 or modified Cas9 or a homolog of Cas9. According to one aspect, the eukaryotic cell is a yeast cell, a plant cell or a mammalian cell. According to one aspect, the RNA includes between about 10 to about 250 nucleotides. According to one aspect, the RNA includes between about 20 to about 100 nucleotides.
[0008] According to one aspect, a method of altering a human cell is provided including transfecting the human cell with a nucleic acid encoding RNA complementary to genomic DNA of the eukaryotic cell, transfecting the human cell with a nucleic acid encoding an enzyme that interacts with the RNA and cleaves the genomic DNA in a site specific manner, wherein the human cell expresses the RNA and the enzyme, the RNA binds to complementary genomic DNA and the enzyme cleaves the genomic DNA in a site specific manner. According to one aspect, the enzyme is Cas9 or modified Cas9 or a homolog of Cas9. According to one aspect, the RNA includes between about 10 to about 250 nucleotides. According to one aspect, the RNA includes between about 20 to about 100 nucleotides.
[0009] According to one aspect, a method of altering a eukaryotic cell at a plurality of genomic DNA sites is provided including transfecting the eukaryotic cell with a plurality of nucleic acids encoding RNAs complementary to different sites on genomic DNA of the eukaryotic cell, transfecting the eukaryotic cell with a nucleic acid encoding an enzyme that interacts with the RNA and cleaves the genomic DNA in a site specific manner, wherein the cell expresses the RNAs and the enzyme, the RNAs bind to complementary genomic DNA and the enzyme cleaves the genomic DNA in a site specific manner. According to one aspect, the enzyme is Cas9. According to one aspect, the eukaryotic cell is a yeast cell, a plant cell or a mammalian cell. According to one aspect, the RNA includes between about 10 to about 250 nucleotides. According to one aspect, the RNA includes between about 20 to about 100 nucleotides.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIGS. 1A-1C depict genome editing in human cells using an engineered type II CRISPR system. (A) sets forth SEQ ID NO:17; (B) sets forth SEQ ID NO:18.
[0011] FIGS. 2A-2F depict RNA-guided genome editing of the native AAVS1 locus in multiple cell types. (A) sets forth SEQ ID NO:19; (E) sets forth SEQ ID NOs:20 and 21.
[0012] FIGS. 3A-3C depict a process mediated by two catalytic domains in the Cas9 protein. (A) sets forth SEQ ID NO:22; (B) sets forth SEQ ID NO:23; (C) sets forth SEQ ID NOs:24-31.
[0013] FIG. 4 depicts that all possible combinations of the repair DNA donor, Cas9 protein, and gRNA were tested for their ability to effect successful HR in 293Ts.
[0014] FIGS. 5A-5B depict the analysis of gRNA and Cas9 mediated genome editing. (B) sets forth SEQ ID NO:19.
[0015] FIGS. 6A-6B depict 293T stable lines each bearing a distinct GFP reporter construct. (A) depicts sequences set forth as SEQ ID NOs; 32-34.
[0016] FIG. 7 depicts gRNAs targeting the flanking GFP sequences of the reporter described in FIG. 1B (in 293Ts).
[0017] FIGS. 8A-8B depict 293T stable lines each bearing a distinct GFP reporter construct. (A) depicts sequences set forth as SEQ ID NOs; 35-36.
[0018] FIGS. 9A-9C depict human iPS cells (PGP1) that were nucleofected with constructs. (A) sets forth SEQ ID NO:19.
[0019] FIGS. 10A-10B depict RNA-guided NHEJ in K562 cells. (A) sets forth SEQ ID NO:19.
[0020] FIGS. 11A-11B depict RNA-guided NHEJ in 293T cells. (A) sets forth SEQ ID NO:19.
[0021] FIGS. 12A-12C depict HR at the endogenous AAVS1 locus using either a dsDNA donor or a short oligonucleotide donor. (C) sets forth SEQ ID NOs:37-38.
[0022] FIGS. 13A-13B depict the methodology for multiplex synthesis, retrieval and U6 expression vector cloning of guide RNAs targeting genes in the human genome. (A) sets forth SEQ ID NOs:39-41.
[0023] FIGS. 14A-14D depict CRISPR mediated RNA-guided transcriptional activation. (A) sets forth SEQ ID NOs:42-43.
[0024] FIGS. 15A-15B depict gRNA sequence flexibility and applications thereof. (A) sets forth SEQ ID NO:44.
DETAILED DESCRIPTION
[0025] According to one aspect, a human codon-optimized version of the Cas9 protein bearing a C-terminus SV40 nuclear localization signal is synthetized and cloned into a mammalian expression system ( FIG. 1A and FIG. 3A ). Accordingly, FIG. 1 is directed to genome editing in human cells using an engineered type II CRISPR system. As shown in FIG. 1A , RNA-guided gene targeting in human cells involves co-expression of the Cas9 protein bearing a C-terminus SV40 nuclear localization signal with one or more guide RNAs (gRNAs) expressed from the human U6 polymerase III promoter. Cas9 unwinds the DNA duplex and cleaves both strands upon recognition of a target sequence by the gRNA, but only if the correct protospacer-adjacent motif (PAM) is present at the 3′ end. Any genomic sequence of the form GN 20 GG can in principle be targeted. As shown in FIG. 1B , a genomically integrated GFP coding sequence is disrupted by the insertion of a stop codon and a 68 bp genomic fragment from the AAVS1 locus. Restoration of the GFP sequence by homologous recombination (HR) with an appropriate donor sequence results in GFP + cells that can be quantitated by FACS. T1 and T2 gRNAs target sequences within the AAVS1 fragment. Binding sites for the two halves of the TAL effector nuclease heterodimer (TALEN) are underlined. As shown in FIG. 1C , bar graph depict HR efficiencies induced by T1, T2, and TALEN-mediated nuclease activity at the target locus, as measured by FACS. Representative FACS plots and microscopy images of the targeted cells are depicted below (scale bar is 100 microns). Data is mean+/−SEM (N=3).
[0026] According to one aspect, to direct Cas9 to cleave sequences of interest, crRNA-tracrRNA fusion transcripts are expressed, hereafter referred to as guide RNAs (gRNAs), from the human U6 polymerase III promoter. According to one aspect, gRNAs are directly transcribed by the cell. This aspect advantageously avoids reconstituting the RNA processing machinery employed by bacterial CRISPR systems ( FIG. 1A and FIG. 3B ) (see references (4, 7-9)). According to one aspect, a method is provided for altering genomic DNA using a U6 transcription initiating with G and a PAM (protospacer-adjacent motif) sequence-NGG following the 20 bp crRNA target. According to this aspect, the target genomic site is in the form of GN 20 GG (See FIG. 3C ).
[0027] According to one aspect, a GFP reporter assay ( FIG. 1B ) in 293T cells was developed similar to one previously described (see reference (10)) to test the functionality of the genome engineering methods described herein. According to one aspect, a stable cell line was established bearing a genomically integrated GFP coding sequence disrupted by the insertion of a stop codon and a 68 bp genomic fragment from the AAVS1 locus that renders the expressed protein fragment non-fluorescent. Homologous recombination (HR) using an appropriate repair donor can restore the normal GFP sequence, which allows one to quantify the resulting GFP + cells by flow activated cell sorting (FACS).
[0028] According to one aspect, a method is provided of homologous recombination (HR). Two gRNAs are constructed, T1 and T2, that target the intervening AAVS1 fragment ( FIG. 1 b ). Their activity to that of a previously described TAL effector nuclease heterodimer (TALEN) targeting the same region (see reference (11)) was compared. Successful HR events were observed using all three targeting reagents, with gene correction rates using the T1 and T2 gRNAs approaching 3% and 8% respectively ( FIG. 1C ). This RNA-mediated editing process was notably rapid, with the first detectable GFP + cells appearing ˜20 hours post transfection compared to ˜40 hours for the AAVS1 TALENs. HR was observed only upon simultaneous introduction of the repair donor, Cas9 protein, and gRNA, confirming that all components are required for genome editing ( FIG. 4 ). While no apparent toxicity associated with Cas9/crRNA expression was noted, work with ZFNs and TALENs has shown that nicking only one strand further reduces toxicity. Accordingly, a Cas9D10A mutant was tested that is known to function as a nickase in vitro, which yielded similar HR but lower non-homologous end joining (NHEJ) rates ( FIG. 5 ) (see references (4, 5)). Consistent with (4) where a related Cas9 protein is shown to cut both strands 6 bp upstream of the PAM, NHEJ data confirmed that most deletions or insertions occurred at the 3′ end of the target sequence ( FIG. 5B ). Also confirmed was that mutating the target genomic site prevents the gRNA from effecting HR at that locus, demonstrating that CRISPR-mediated genome editing is sequence specific ( FIG. 6 ). It was showed that two gRNAs targeting sites in the GFP gene, and also three additional gRNAs targeting fragments from homologous regions of the DNA methyl transferase 3a (DNMT3a) and DNMT3b genes could sequence specifically induce significant HR in the engineered reporter cell lines ( FIG. 7 , 8 ). Together these results confirm that RNA-guided genome targeting in human cells induces robust HR across multiple target sites.
[0029] According to certain aspects, a native locus was modified. gRNAs were used to target the AAVS1 locus located in the PPP1R12C gene on chromosome 19, which is ubiquitously expressed across most tissues ( FIG. 2A ) in 293Ts, K562s, and PGP1 human iPS cells (see reference (12)) and analyzed the results by next-generation sequencing of the targeted locus. Accordingly, FIG. 2 is directed to RNA-guided genome editing of the native AAVS1 locus in multiple cell types. As shown in FIG. 2A , T1 (red) and T2 (green) gRNAs target sequences in an intron of the PPP1R12C gene within the chromosome 19 AAVS1 locus. As shown in FIG. 2B , total count and location of deletions caused by NHEJ in 293Ts, K562s, and PGP1 iPS cells following expression of Cas9 and either T1 or T2 gRNAs as quantified by next-generation sequencing is provided. Red and green dash lines demarcate the boundaries of the T1 and T2 gRNA targeting sites. NHEJ frequencies for T1 and T2 gRNAs were 10% and 25% in 293T, 13% and 38% in K562, and 2% and 4% in PGP1 iPS cells, respectively. As shown in FIG. 2C , DNA donor architecture for HR at the AAVS1 locus, and the locations of sequencing primers (arrows) for detecting successful targeted events, are depicted. As shown in FIG. 2D , PCR assay three days post transfection demonstrates that only cells expressing the donor, Cas9 and T2 gRNA exhibit successful HR events. As shown in FIG. 2E , successful HR was confirmed by Sanger sequencing of the PCR amplicon showing that the expected DNA bases at both the genome-donor and donor-insert boundaries are present. As shown in FIG. 2F , successfully targeted clones of 293T cells were selected with puromycin for 2 weeks. Microscope images of two representative GFP+ clones is shown (scale bar is 100 microns).
[0030] Consistent with results for the GFP reporter assay, high numbers of NHEJ events were observed at the endogenous locus for all three cell types. The two gRNAs T1 and T2 achieved NHEJ rates of 10 and 25% in 293Ts, 13 and 38% in K562s, and 2 and 4% in PGP1-iPS cells, respectively ( FIG. 2B ). No overt toxicity was observed from the Cas9 and crRNA expression required to induce NHEJ in any of these cell types ( FIG. 9 ). As expected, NHEJ-mediated deletions for T1 and T2 were centered around the target site positions, further validating the sequence specificity of this targeting process ( FIG. 9 , 10 , 11 ). Simultaneous introduction of both T1 and T2 gRNAs resulted in high efficiency deletion of the intervening 19 bp fragment ( FIG. 10 ), demonstrating that multiplexed editing of genomic loci is feasible using this approach.
[0031] According to one aspect, HR is used to integrate either a dsDNA donor construct (see reference (13)) or an oligo donor into the native AAVS1 locus ( FIG. 2C , FIG. 12 ). HR-mediated integration was confirmed using both approaches by PCR ( FIG. 2D , FIG. 12 ) and Sanger sequencing ( FIG. 2E ). 293T or iPS clones were readily derived from the pool of modified cells using puromycin selection over two weeks ( FIG. 2F , FIG. 12 ). These results demonstrate that Cas9 is capable of efficiently integrating foreign DNA at endogenous loci in human cells. Accordingly, one aspect of the present disclosure includes a method of integrating foreign DNA into the genome of a cell using homologous recombination and Cas9.
[0032] According to one aspect, an RNA-guided genome editing system is provided which can readily be adapted to modify other genomic sites by simply modifying the sequence of the gRNA expression vector to match a compatible sequence in the locus of interest. According to this aspect, 190,000 specifically gRNA-targetable sequences targeting about 40.5% exons of genes in the human genome were generated. These target sequences were incorporated into a 200 bp format compatible with multiplex synthesis on DNA arrays (see reference (14)) ( FIG. 13 ). According to this aspect, a ready genome-wide reference of potential target sites in the human genome and a methodology for multiplex gRNA synthesis is provided.
[0033] According to one aspect, methods are provided for multiplexing genomic alterations in a cell by using one or more or a plurality of RNA/enzyme systems described herein to alter the genome of a cell at a plurality of locations. According to one aspect, target sites perfectly match the PAM sequence NGG and the 8-12 base “seed sequence” at the 3′ end of the gRNA. According to certain aspects, perfect match is not required of the remaining 8-12 bases. According to certain aspects, Cas9 will function with single mismatches at the 5′ end. According to certain aspects, the target locus's underlying chromatin structure and epigenetic state may affect efficiency of Cas9 function. According to certain aspects, Cas9 homologs having higher specificity are included as useful enzymes. One of skill in the art will be able to identify or engineer suitable Cas9 homologs. According to one aspect, CRISPR-targetable sequences include those having different PAM requirements (see reference (9)), or directed evolution. According to one aspect, inactivating one of the Cas9 nuclease domains increases the ratio of HR to NHEJ and may reduce toxicity ( FIG. 3A , FIG. 5 ) (4, 5), while inactivating both domains may enable Cas9 to function as a retargetable DNA binding protein. Embodiments of the present disclosure have broad utility in synthetic biology (see references (21, 22)), the direct and multiplexed perturbation of gene networks (see references (13, 23)), and targeted ex vivo (see references (24-26)) and in vivo gene therapy (see reference (27)).
[0034] According to certain aspects, a “re-engineerable organism” is provided as a model system for biological discovery and in vivo screening. According to one aspect, a “re-engineerable mouse” bearing an inducible Cas9 transgene is provided, and localized delivery (using adeno-associated viruses, for example) of libraries of gRNAs targeting multiple genes or regulatory elements allow one to screen for mutations that result in the onset of tumors in the target tissue type. Use of Cas9 homologs or nuclease-null variants bearing effector domains (such as activators) allow one to multiplex activate or repress genes in vivo. According to this aspect, one could screen for factors that enable phenotypes such as: tissue-regeneration, trans-differentiation etc. According to certain aspects, (a) use of DNA-arrays enables multiplex synthesis of defined gRNA libraries (refer FIG. 13 ); and (b) gRNAs being small in size (refer FIG. 3 b ) are packaged and delivered using a multitude of non-viral or viral delivery methods.
[0035] According to one aspect, the lower toxicities observed with “nickases” for genome engineering applications is achieved by inactivating one of the Cas9 nuclease domains, either the nicking of the DNA strand base-paired with the RNA or nicking its complement. Inactivating both domains allows Cas9 to function as a retargetable DNA binding protein. According to one aspect, the Cas9 retargetable DNA binding protein is attached
[0000] (a) to transcriptional activation or repression domains for modulating target gene expression, including but not limited to chromatin remodeling, histone modification, silencing, insulation, direct interactions with the transcriptional machinery;
(b) to nuclease domains such as FokI to enable ‘highly specific’ genome editing contingent upon dimerization of adjacent gRNA-Cas9 complexes;
(c) to fluorescent proteins for visualizing genomic loci and chromosome dynamics; or
(d) to other fluorescent molecules such as protein or nucleic acid bound organic fluorophores, quantum dots, molecular beacons and echo probes or molecular beacon replacements;
(e) to multivalent ligand-binding protein domains that enable programmable manipulation of genome-wide 3D architecture.
[0036] According to one aspect, the transcriptional activation and repression components can employ CRISPR systems naturally or synthetically orthogonal, such that the gRNAs only bind to the activator or repressor class of Cas. This allows a large set of gRNAs to tune multiple targets.
[0037] According to certain aspects, the use of gRNAs provide the ability to multiplex than mRNAs in part due to the smaller size—100 vs. 2000 nucleotide lengths respectively. This is particularly valuable when nucleic acid delivery is size limited, as in viral packaging. This enables multiple instances of cleavage, nicking, activation, or repression—or combinations thereof. The ability to easily target multiple regulatory targets allows the coarse-or-fine-tuning or regulatory networks without being constrained to the natural regulatory circuits downstream of specific regulatory factors (e.g. the 4 mRNAs used in reprogramming fibroblasts into IPSCs). Examples of multiplexing applications include:
[0000] 1. Establishing (major and minor) histocompatibility alleles, haplotypes, and genotypes for human (or animal) tissue/organ transplantation. This aspect results e.g. in HLA homozygous cell lines or humanized animal breeds—or—a set of gRNAs capable of superimposing such HLA alleles onto an otherwise desirable cell lines or breeds.
2. Multiplex cis-regulatory element (CRE=signals for transcription, splicing, translation, RNA and protein folding, degradation, etc.) mutations in a single cell (or a collection of cells) can be used for efficiently studying the complex sets of regulatory interaction that can occur in normal development or pathological, synthetic or pharmaceutical scenarios. According to one aspect, the CREs are (or can be made) somewhat orthogonal (i.e. low cross talk) so that many can be tested in one setting—e.g. in an expensive animal embryo time series. One exemplary application is with RNA fluorescent in situ sequencing (FISSeq).
3. Multiplex combinations of CRE mutations and/or epigenetic activation or repression of CREs can be used to alter or reprogram iPSCs or ESCs or other stem cells or non-stem cells to any cell type or combination of cell types for use in organs-on-chips or other cell and organ cultures for purposes of testing pharmaceuticals (small molecules, proteins, RNAs, cells, animal, plant or microbial cells, aerosols and other delivery methods), transplantation strategies, personalization strategies, etc.
4. Making multiplex mutant human cells for use in diagnostic testing (and/or DNA sequencing) for medical genetics. To the extent that the chromosomal location and context of a human genome allele (or epigenetic mark) can influence the accuracy of a clinical genetic diagnosis, it is important to have alleles present in the correct location in a reference genome—rather than in an ectopic (aka transgenic) location or in a separate piece of synthetic DNA. One embodiment is a series of independent cell lines one per each diagnostic human SNP, or structural variant. Alternatively, one embodiment includes multiplex sets of alleles in the same cell. In some cases multiplex changes in one gene (or multiple genes) will be desirable under the assumption of independent testing. In other cases, particular haplotype combinations of alleles allows testing of sequencing (genotyping) methods which accurately establish haplotype phase (i.e. whether one or both copies of a gene are affected in an individual person or somatic cell type.
5. Repetitive elements or endogenous viral elements can be targeted with engineered Cas+gRNA systems in microbes, plants, animals, or human cells to reduce deleterious transposition or to aid in sequencing or other analytic genomic/transcriptomic/proteomic/diagnostic tools (in which nearly identical copies can be problematic).
[0038] The following references identified by number in the foregoing section are hereby incorporated by reference in their entireties.
1. B. Wiedenheft, S. H. Sternberg, J. A. Doudna, Nature 482, 331 (Feb. 16, 2012). 2. D. Bhaya, M. Davison, R. Barrangou, Annual review of genetics 45, 273 (2011). 3. M. P. Terns, R. M. Terns, Current opinion in microbiology 14, 321 (June, 2011). 4. M. Jinek et al., Science 337, 816 (Aug. 17, 2012). 5. G. Gasiunas, R. Barrangou, P. Horvath, V. Siksnys, Proceedings of the National Academy of Sciences of the United States of America 109, E2579 (Sep. 25, 2012). 6. R. Sapranauskas et al., Nucleic acids research 39, 9275 (November, 2011). 7. T. R. Brummelkamp, R. Bernards, R. Agami, Science 296, 550 (Apr. 19, 2002). 8. M. Miyagishi, K. Taira, Nature biotechnology 20, 497 (May, 2002). 9. E. Deltcheva et al., Nature 471, 602 (Mar. 31, 2011). 10. J. Zou, P. Mali, X. Huang, S. N. Dowey, L. Cheng, Blood 118, 4599 (Oct. 27, 2011). 11. N. E. Sanjana et al., Nature protocols 7, 171 (January, 2012). 12. J. H. Lee et al., PLoS Genet 5, e1000718 (November, 2009). 13. D. Hockemeyer et al., Nature biotechnology 27, 851 (September, 2009). 14. S. Kosuri et al., Nature biotechnology 28, 1295 (December, 2010). 15. V. Pattanayak, C. L. Ramirez, J. K. Joung, D. R. Liu, Nature methods 8, 765 (September, 2011). 16. N. M. King, O. Cohen-Haguenauer, Molecular therapy: the journal of the American Society of Gene Therapy 16, 432 (March, 2008). 17. Y. G. Kim, J. Cha, S. Chandrasegaran, Proceedings of the National Academy of Sciences of the United States of America 93, 1156 (Feb. 6, 1996). 18. E. J. Rebar, C. O. Pabo, Science 263, 671 (Feb. 4, 1994). 19. J. Boch et al., Science 326, 1509 (Dec. 11, 2009). 20. M. J. Moscou, A. J. Bogdanove, Science 326, 1501 (Dec. 11, 2009). 21. A. S. Khalil, J. J. Collins, Nature reviews. Genetics 11, 367 (May, 2010). 22. P. E. Purnick, R. Weiss, Nature reviews. Molecular cell biology 10, 410 (June, 2009). 23. J. Zou et al., Cell stem cell 5, 97 (Jul. 2, 2009). 24. N. Holt et al., Nature biotechnology 28, 839 (August, 2010). 25. F. D. Urnov et al., Nature 435, 646 (Jun. 2, 2005). 26. A. Lombardo et al., Nature biotechnology 25, 1298 (November, 2007). 27. H. Li et al., Nature 475, 217 (Jul. 14, 2011).
[0066] The following examples are set forth as being representative of the present disclosure. These examples are not to be construed as limiting the scope of the present disclosure as these and other equivalent embodiments will be apparent in view of the present disclosure, figures and accompanying claims.
EXAMPLE I
The Type II CRISPR-Cas System
[0067] According to one aspect, embodiments of the present disclosure utilize short RNA to identify foreign nucleic acids for activity by a nuclease in a eukaryotic cell. According to a certain aspect of the present disclosure, a eukaryotic cell is altered to include within its genome nucleic acids encoding one or more short RNA and one or more nucleases which are activated by the binding of a short RNA to a target DNA sequence. According to certain aspects, exemplary short RNA/enzyme systems may be identified within bacteria or archaea, such as (CRISPR)/CRISPR-associated (Cas) systems that use short RNA to direct degradation of foreign nucleic acids. CRISPR (“clustered regularly interspaced short palindromic repeats”) defense involves acquisition and integration of new targeting “spacers” from invading virus or plasmid DNA into the CRISPR locus, expression and processing of short guiding CRISPR RNAs (crRNAs) consisting of spacer-repeat units, and cleavage of nucleic acids (most commonly DNA) complementary to the spacer.
[0068] Three classes of CRISPR systems are generally known and are referred to as Type I, Type II or Type III). According to one aspect, a particular useful enzyme according to the present disclosure to cleave dsDNA is the single effector enzyme, Cas9, common to Type II. (See reference (1)). Within bacteria, the Type II effector system consists of a long pre-crRNA transcribed from the spacer-containing CRISPR locus, the multifunctional Cas9 protein, and a tracrRNA important for gRNA processing. The tracrRNAs hybridize to the repeat regions separating the spacers of the pre-crRNA, initiating dsRNA cleavage by endogenous RNase III, which is followed by a second cleavage event within each spacer by Cas9, producing mature crRNAs that remain associated with the tracrRNA and Cas9. According to one aspect, eukaryotic cells of the present disclosure are engineered to avoid use of RNase III and the crRNA processing in general. See reference (2).
[0069] According to one aspect, the enzyme of the present disclosure, such as Cas9 unwinds the DNA duplex and searches for sequences matching the crRNA to cleave. Target recognition occurs upon detection of complementarity between a “protospacer” sequence in the target DNA and the remaining spacer sequence in the crRNA. Importantly, Cas9 cuts the DNA only if a correct protospacer-adjacent motif (PAM) is also present at the 3′ end. According to certain aspects, different protospacer-adjacent motif can be utilized. For example, the S. pyogenes system requires an NGG sequence, where N can be any nucleotide. S. thermophilus Type II systems require NGGNG (see reference (3)) and NNAGAAW (see reference (4)), respectively, while different S. mutans systems tolerate NGG or NAAR (see reference (5)). Bioinformatic analyses have generated extensive databases of CRISPR loci in a variety of bacteria that may serve to identify additional useful PAMs and expand the set of CRISPR-targetable sequences (see references (6, 7)). In S. thermophilus , Cas9 generates a blunt-ended double-stranded break 3 bp prior to the 3′ end of the protospacer (see reference (8)), a process mediated by two catalytic domains in the Cas9 protein: an HNH domain that cleaves the complementary strand of the DNA and a RuvC-like domain that cleaves the non-complementary strand (See FIG. 1A and FIG. 3 ). While the S. pyogenes system has not been characterized to the same level of precision, DSB formation also occurs towards the 3′ end of the protospacer. If one of the two nuclease domains is inactivated, Cas9 will function as a nickase in vitro (see reference (2)) and in human cells (see FIG. 5 ).
[0070] According to one aspect, the specificity of gRNA-directed Cas9 cleavage is used as a mechanism for genome engineering in a eukaryotic cell. According to one aspect, hybridization of the gRNA need not be 100 percent in order for the enzyme to recognize the gRNA/DNA hybrid and affect cleavage. Some off-target activity could occur. For example, the S. pyogenes system tolerates mismatches in the first 6 bases out of the 20 bp mature spacer sequence in vitro. According to one aspect, greater stringency may be beneficial in vivo when potential off-target sites matching (last 14 bp) NGG exist within the human reference genome for the gRNAs. The effect of mismatches and enzyme activity in general are described in references (9), (2), (10), and (4).
[0071] According to certain aspects, specificity may be improved. When interference is sensitive to the melting temperature of the gRNA-DNA hybrid, AT-rich target sequences may have fewer off-target sites. Carefully choosing target sites to avoid pseudo-sites with at least 14 bp matching sequences elsewhere in the genome may improve specificity. The use of a Cas9 variant requiring a longer PAM sequence may reduce the frequency of off-target sites. Directed evolution may improve Cas9 specificity to a level sufficient to completely preclude off-target activity, ideally requiring a perfect 20 bp gRNA match with a minimal PAM. Accordingly, modification to the Cas9 protein is a representative embodiment of the present disclosure. As such, novel methods permitting many rounds of evolution in a short timeframe (see reference (11) and envisioned. CRISPR systems useful in the present disclosure are described in references (12, 13).
EXAMPLE II
Plasmid Construction
[0072] The Cas9 gene sequence was human codon optimized and assembled by hierarchical fusion PCR assembly of 9 500 bp gBlocks ordered from IDT. FIG. 3A for the engineered type II CRISPR system for human cells shows the expression format and full sequence of the cas9 gene insert. The RuvC-like and HNH motifs, and the C-terminus SV40 NLS are respectively highlighted by blue, brown and orange colors. Cas9_D10A was similarly constructed. The resulting full-length products were cloned into the pcDNA3.3-TOPO vector (Invitrogen). The target gRNA expression constructs were directly ordered as individual 455 bp gBlocks from IDT and either cloned into the pCR-BluntII-TOPO vector (Invitrogen) or per amplified. FIG. 3B shows the U6 promoter based expression scheme for the guide RNAs and predicted RNA transcript secondary structure. The use of the U6 promoter constrains the 1 st position in the RNA transcript to be a ‘G’ and thus all genomic sites of the form GN 20 GG can be targeted using this approach. FIG. 3C shows the 7 gRNAs used.
[0073] The vectors for the HR reporter assay involving a broken GFP were constructed by fusion PCR assembly of the GFP sequence bearing the stop codon and 68 bp AAVS1 fragment (or mutants thereof; see FIG. 6 ), or 58 bp fragments from the DNMT3a and DNMT3b genomic loci (see FIG. 8 ) assembled into the EGIP lentivector from Addgene (plasmid #26777). These lentivectors were then used to establish the GFP reporter stable lines. TALENs used in this study were constructed using the protocols described in (14). All DNA reagents developed in this study are available at Addgene.
EXAMPLE III
Cell Culture
[0074] PGP1 iPS cells were maintained on Matrigel (BD Biosciences)-coated plates in mTeSR1 (Stemcell Technologies). Cultures were passaged every 5-7 d with TrypLE Express (Invitrogen). K562 cells were grown and maintained in RPMI (Invitrogen) containing 15% FBS. HEK 293T cells were cultured in Dulbecco's modified Eagle's medium (DMEM, Invitrogen) high glucose supplemented with 10% fetal bovine serum (FBS, Invitrogen), penicillin/streptomycin (pen/strep, Invitrogen), and non-essential amino acids (NEAA, Invitrogen). All cells were maintained at 37° C. and 5% CO 2 in a humidified incubator.
EXAMPLE IV
Gene Targeting of PGP1 iPS, K562 and 293Ts
[0075] PGP1 iPS cells were cultured in Rho kinase (ROCK) inhibitor (Calbiochem) 2 h before nucleofection. Cells were harvest using TrypLE Express (Invitrogen) and 2×10 6 cells were resuspended in P3 reagent (Lonza) with 1 μg Cas9 plasmid, 1 μg gRNA and/or 1 μg DNA donor plasmid, and nucleofected according to manufacturer's instruction (Lonza). Cells were subsequently plated on an mTeSR1-coated plate in mTeSR1 medium supplemented with ROCK inhibitor for the first 24 h. For K562s, 2×10 6 cells were resuspended in SF reagent (Lonza) with 1 μg Cas9 plasmid, 1 μg gRNA and/or 1 μg DNA donor plasmid, and nucleofected according to manufacturer's instruction (Lonza). For 293Ts, 0.1×10 6 cells were transfected with 1 μg Cas9 plasmid, 1 μg gRNA and/or 1 μg DNA donor plasmid using Lipofectamine 2000 as per the manufacturer's protocols. The DNA donors used for endogenous AAVS1 targeting were either a dsDNA donor ( FIG. 2C ) or a 90mer oligonucleotide. The former has flanking short homology arms and a SA-2A-puromycin-CaGGS-eGFP cassette to enrich for successfully targeted cells.
[0076] The targeting efficiency was assessed as follows. Cells were harvested 3 days after nucleofection and the genomic DNA of ˜1×10 6 cells was extracted using prepGEM (ZyGEM). PCR was conducted to amplify the targeting region with genomic DNA derived from the cells and amplicons were deep sequenced by MiSeq Personal Sequencer (Illumina) with coverage >200,000 reads. The sequencing data was analyzed to estimate NHEJ efficiencies. The reference AAVS1 sequence analyzed is:
[0000]
(SEQ ID NO: 1)
CACTTCAGGACAGCATGTTTGCTGCCTCCAGGGATCCTGTGTCCCCGAGC
TGGGACCACCTTATATTCCCAGGGCCGGTTAATGTGGCTCTGGTTCTGGG
TACTTTTATCTGTCCCCTCCACCCCACAGTGGGGCCACTAGGGACAGGAT
TGGTGACAGAAAAGCCCCATCCTTAGGCCTCCTCCTTCCTAGTCTCCTGA
TATTGGGTCTAACCCCCACCTCCTGTTAGGCAGATTCCTTATCTGGTGAC
ACACCCCCATTTCCTGGA
[0077] The PCR primers for amplifying the targeting regions in the human genome are:
[0000]
AAVS1-R
(SEQ ID NO: 2)
CTCGGCATTCCTGCTGAACCGCTCTTCCGATCTacaggaggtgggggtt
agac
AAVS1-F.1
(SEQ ID NO: 3)
ACACTCTTTCCCTACACGACGCTCTTCCGATCTCGTGATtatattccca
gggccggtta
AAVS1-F.2
(SEQ ID NO: 4)
ACACTCTTTCCCTACACGACGCTCTTCCGATCTACATCGtatattccca
gggccggtta
AAVS1-F.3
(SEQ ID NO: 5)
ACACTCTTTCCCTACACGACGCTCTTCCGATCTGCCTAAtatattccca
gggccggtta
AAVS1-F.4
(SEQ ID NO: 6)
ACACTCTTTCCCTACACGACGCTCTTCCGATCTTGGTCAtatattccca
gggccggtta
AAVS1-F.5
(SEQ ID NO: 7)
ACACTCTTTCCCTACACGACGCTCTTCCGATCTCACTGTtatattccca
gggccggtta
AAVS1-F.6
(SEQ ID NO: 8)
ACACTCTTTCCCTACACGACGCTCTTCCGATCTATTGGCtatattccca
gggccggtta
AAVS1-F.7
(SEQ ID NO: 9)
ACACTCTTTCCCTACACGACGCTCTTCCGATCTGATCTGtatattccca
gggccggtta
AAVS1-F.8
(SEQ ID NO: 10)
ACACTCTTTCCCTACACGACGCTCTTCCGATCTTCAAGTtatattccca
gggccggtta
AAVS1-F.9
(SEQ ID NO: 11)
ACACTCTTTCCCTACACGACGCTCTTCCGATCTCTGATCtatattccca
gggccggtta
AAVS1-F.10
(SEQ ID NO: 12)
ACACTCTTTCCCTACACGACGCTCTTCCGATCTAAGCTAtatattccca
gggccggtta
AAVS1-F.11
(SEQ ID NO: 13)
ACACTCTTTCCCTACACGACGCTCTTCCGATCTGTAGCCtatattccca
gggccggtta
AAVS1-F.12
(SEQ ID NO: 14)
ACACTCTTTCCCTACACGACGCTCTTCCGATCTTACAAGtatattccca
gggccggtta
[0078] To analyze the HR events using the DNA donor in FIG. 2C , the primers used were:
[0000]
HR_AAVS1-F
(SEQ ID NO: 15)
CTGCCGTCTCTCTCCTGAGT
HR_Puro-R
(SEQ ID NO: 16)
GTGGGCTTGTACTCGGTCAT
EXAMPLE V
Bioinformatics Approach for Computing Human Exon CRISPR Targets and Methodology for Their Multiplexed Synthesis
[0079] A set of gRNA gene sequences that maximally target specific locations in human exons but minimally target other locations in the genome were determined as follows. According to one aspect, maximally efficient targeting by a gRNA is achieved by 23nt sequences, the 5′-most 20nt of which exactly complement a desired location, while the three 3′-most bases must be of the form NGG. Additionally, the 5′-most nt must be a G to establish a pol-III transcription start site. However, according to (2), mispairing of the six 5′-most nt of a 20 bp gRNA against its genomic target does not abrogate Cas9-mediated cleavage so long as the last 14nt pairs properly, but mispairing of the eight 5′-most nt along with pairing of the last 12 nt does, while the case of the seven 5-most nt mispairs and 13 3′ pairs was not tested. To be conservative regarding off-target effects, one condition was that the case of the seven 5′-most mispairs is, like the case of six, permissive of cleavage, so that pairing of the 3′-most 13nt is sufficient for cleavage. To identify CRISPR target sites within human exons that should be cleavable without off-target cuts, all 23 bp sequences of the form 5′-GBBBB BBBBB BBBBB BBBBB NGG-3′ (form 1) were examined, where the B's represent the bases at the exon location, for which no sequence of the form 5′-NNNNN NNBBB BBBBB BBBBB NGG-3′ (form 2) existed at any other location in the human genome. Specifically, (i) a BED file of locations of coding regions of all RefSeq genes the GRCh37/hg19 human genome from the UCSC Genome Browser (15-17) was downloaded. Coding exon locations in this BED file comprised a set of 346089 mappings of RefSeq mRNA accessions to the hg19 genome. However, some RefSeq mRNA accessions mapped to multiple genomic locations (probable gene duplications), and many accessions mapped to subsets of the same set of exon locations (multiple isoforms of the same genes). To distinguish apparently duplicated gene instances and consolidate multiple references to the same genomic exon instance by multiple RefSeq isoform accessions, (ii) unique numerical suffixes to 705 RefSeq accession numbers that had multiple genomic locations were added, and (iii) the mergeBed function of BEDTools (18) (v2.16.2-zip-87e3926) was used to consolidate overlapping exon locations into merged exon regions. These steps reduced the initial set of 346089 RefSeq exon locations to 192783 distinct genomic regions. The hg19 sequence for all merged exon regions were downloaded using the UCSC Table Browser, adding 20 bp of padding on each end. (iv) Using custom perl code, 1657793 instances of form 1 were identified within this exonic sequence. (v) These sequences were then filtered for the existence of off-target occurrences of form 2: For each merged exon form 1 target, the 3′-most 13 bp specific (B) “core” sequences were extracted and, for each core generated the four 16 bp sequences 5′-BBB BBBBB BBBBB NGG-3′ (N=A, C, G, and T), and searched the entire hg19 genome for exact matches to these 6631172 sequences using Bowtie version 0.12.8 (19) using the parameters -l 16 -v 0 -k 2. Any exon target site for which there was more than a single match was rejected. Note that because any specific 13 bp core sequence followed by the sequence NGG confers only 15 bp of specificity, there should be on average ˜5.6 matches to an extended core sequence in a random ˜3 Gb sequence (both strands). Therefore, most of the 1657793 initially identified targets were rejected; however 189864 sequences passed this filter. These comprise the set of CRISPR-targetable exonic locations in the human genome. The 189864 sequences target locations in 78028 merged exonic regions (˜40.5% of the total of 192783 merged human exon regions) at a multiplicity of ˜2.4 sites per targeted exonic region. To assess targeting at a gene level, RefSeq mRNA mappings were clustered so that any two RefSeq accessions (including the gene duplicates distinguished in (ii)) that overlap a merged exon region are counted as a single gene cluster, the 189864 exonic specific CRISPR sites target 17104 out of 18872 gene clusters (˜90.6% of all gene clusters) at a multiplicity of ˜11.1 per targeted gene cluster. (Note that while these gene clusters collapse RefSeq mRNA accessions that represent multiple isoforms of a single transcribed gene into a single entity, they will also collapse overlapping distinct genes as well as genes with antisense transcripts.) At the level of original RefSeq accessions, the 189864 sequences targeted exonic regions in 30563 out of a total of 43726 (˜69.9%) mapped RefSeq accessions (including distinguished gene duplicates) at a multiplicity of ˜6.2 sites per targeted mapped RefSeq accession.
[0080] According to one aspect, the database can be refined by correlating performance with factors, such as base composition and secondary structure of both gRNAs and genomic targets (20, 21), and the epigenetic state of these targets in human cell lines for which this information is available (22).
EXAMPLE VI
Multiplex Synthesis
[0081] The target sequences were incorporated into a 200 bp format that is compatible for multiplex synthesis on DNA arrays (23, 24). According to one aspect the method allows for targeted retrieval of a specific or pools of gRNA sequences from the DNA array based oligonucleotide pool and its rapid cloning into a common expression vector ( FIG. 13A ). Specifically, a 12 k oligonucleotide pool from CustomArray Inc. was synthesized. Furthermore, gRNAs of choice from this library ( FIG. 13B ) were successfully retrieved. We observed an error rate of ˜4 mutations per 1000 bp of synthesized DNA.
EXAMPLE VII
RNA-Guided Genome Editing Requires Both Cas9 and Guide RNA for Successful Targeting
[0082] Using the GFP reporter assay described in FIG. 1B , all possible combinations of the repair DNA donor, Cas9 protein, and gRNA were tested for their ability to effect successful HR (in 293Ts). As shown in FIG. 4 , GFP+ cells were observed only when all the 3 components were present, validating that these CRISPR components are essential for RNA-guided genome editing. Data is mean+/−SEM (N=3).
EXAMPLE VIII
Analysis of gRNA and Cas9 Mediated Genome Editing
[0083] The CRISPR mediated genome editing process was examined using either (A) a GFP reporter assay as described earlier results of which are shown in FIG. 5A , and (B) deep sequencing of the targeted loci (in 293Ts), results of which are shown in FIG. 5B . As comparison, a D10A mutant for Cas9 was tested that has been shown in earlier reports to function as a nickase in in vitro assays. As shown in FIG. 5 , both Cas9 and Cas9D10A can effect successful HR at nearly similar rates. Deep sequencing however confirms that while Cas9 shows robust NHEJ at the targeted loci, the D10A mutant has significantly diminished NHEJ rates (as would be expected from its putative ability to only nick DNA). Also, consistent with the known biochemistry of the Cas9 protein, NHEJ data confirms that most base-pair deletions or insertions occurred near the 3′ end of the target sequence: the peak is ˜3-4 bases upstream of the PAM site, with a median deletion frequency of ˜9-10 bp. Data is mean+/−SEM (N=3).
EXAMPLE IX
RNA-Guided Genome Editing is Target Sequence Specific
[0084] Similar to the GFP reporter assay described in FIG. 1B , 3 293T stable lines each bearing a distinct GFP reporter construct were developed. These are distinguished by the sequence of the AAVS1 fragment insert (as indicated in the FIG. 6 ). One line harbored the wild-type fragment while the two other lines were mutated at 6 bp (highlighted in red). Each of the lines was then targeted by one of the following 4 reagents: a GFP-ZFN pair that can target all cell types since its targeted sequence was in the flanking GFP fragments and hence present in along cell lines; a AAVS1 TALEN that could potentially target only the wt-AAVS1 fragment since the mutations in the other two lines should render the left TALEN unable to bind their sites; the T1 gRNA which can also potentially target only the wt-AAVS1 fragment, since its target site is also disrupted in the two mutant lines; and finally the T2 gRNA which should be able to target all 3 cell lines since, unlike the T1 gRNA, its target site is unaltered among the 3 lines. ZFN modified all 3 cell types, the AAVS1 TALENs and the T1 gRNA only targeted the wt-AAVS1 cell type, and the T2 gRNA successfully targets all 3 cell types. These results together confirm that the guide RNA mediated editing is target sequence specific. Data is mean+/−SEM (N=3).
EXAMPLE X
Guide RNAs Targeted to the GFP Sequence Enable Robust Genome Editing
[0085] In addition to the 2 gRNAs targeting the AAVS1 insert, two additional gRNAs targeting the flanking GFP sequences of the reporter described in FIG. 1B (in 293Ts) were tested. As shown in FIG. 7 , these gRNAs were also able to effect robust HR at this engineered locus. Data is mean+/−SEM (N=3).
EXAMPLE XI
RNA-Guided Genome Editing is Target Sequence Specific, and Demonstrates Similar Targeting Efficiencies as ZFNs or TALENs
[0086] Similar to the GFP reporter assay described in FIG. 1B , two 293T stable lines each bearing a distinct GFP reporter construct were developed. These are distinguished by the sequence of the fragment insert (as indicated in FIG. 8 ). One line harbored a 58 bp fragment from the DNMT3a gene while the other line bore a homologous 58 bp fragment from the DNMT3b gene. The sequence differences are highlighted in red. Each of the lines was then targeted by one of the following 6 reagents: a GFP-ZFN pair that can target all cell types since its targeted sequence was in the flanking GFP fragments and hence present in along cell lines; a pair of TALENs that potentially target either DNMT3a or DNMT3b fragments; a pair of gRNAs that can potentially target only the DNMT3a fragment; and finally a gRNA that should potentially only target the DNMT3b fragment. As indicated in FIG. 8 , the ZFN modified all 3 cell types, and the TALENs and gRNAs only their respective targets. Furthermore the efficiencies of targeting were comparable across the 6 targeting reagents. These results together confirm that RNA-guided editing is target sequence specific and demonstrates similar targeting efficiencies as ZFNs or TALENs. Data is mean+/−SEM (N=3).
EXAMPLE XII
RNA-Guided NHEJ in Human iPS Cells
[0087] Human iPS cells (PGP1) were nucleofected with constructs indicated in the left panel of FIG. 9 . 4 days after nucleofection, NHEJ rate was measured by assessing genomic deletion and insertion rate at double-strand breaks (DSBs) by deep sequencing. Panel 1: Deletion rate detected at targeting region. Red dash lines: boundary of T1 RNA targeting site; green dash lines: boundary of T2 RNA targeting site. The deletion incidence at each nucleotide position was plotted in black lines and the deletion rate as the percentage of reads carrying deletions was calculated. Panel 2: Insertion rate detected at targeting region. Red dash lines: boundary of T1 RNA targeting site; green dash lines: boundary of T2 RNA targeting site. The incidence of insertion at the genomic location where the first insertion junction was detected was plotted in black lines and the insertion rate as the percentage of reads carrying insertions was calculated. Panel 3: Deletion size distribution. The frequencies of different size deletions among the whole NHEJ population was plotted. Panel 4: insertion size distribution. The frequencies of different sizes insertions among the whole NHEJ population was plotted. iPS targeting by both gRNAs is efficient (2-4%), sequence specific (as shown by the shift in position of the NHEJ deletion distributions), and reaffirming the results of FIG. 4 , the NGS-based analysis also shows that both the Cas9 protein and the gRNA are essential for NHEJ events at the target locus.
EXAMPLE XIII
RNA-Guided NHEJ in K562 Cells
[0088] K562 cells were nucleated with constructs indicated in the left panel of FIG. 10 . 4 days after nucleofection, NHEJ rate was measured by assessing genomic deletion and insertion rate at DSBs by deep sequencing. Panel 1: Deletion rate detected at targeting region. Red dash lines: boundary of T1 RNA targeting site; green dash lines: boundary of T2 RNA targeting site. The deletion incidence at each nucleotide position was plotted in black lines and the deletion rate as the percentage of reads carrying deletions was calculated. Panel 2: Insertion rate detected at targeting region. Red dash lines: boundary of T1 RNA targeting site; green dash lines: boundary of T2 RNA targeting site. The incidence of insertion at the genomic location where the first insertion junction was detected was plotted in black lines and the insertion rate as the percentage of reads carrying insertions was calculated. Panel 3: Deletion size distribution. The frequencies of different size deletions among the whole NHEJ population was plotted. Panel 4: insertion size distribution. The frequencies of different sizes insertions among the whole NHEJ population was plotted. K562 targeting by both gRNAs is efficient (13-38%) and sequence specific (as shown by the shift in position of the NHEJ deletion distributions). Importantly, as evidenced by the peaks in the histogram of observed frequencies of deletion sizes, simultaneous introduction of both T1 and T2 guide RNAs resulted in high efficiency deletion of the intervening 19 bp fragment, demonstrating that multiplexed editing of genomic loci is also feasible using this approach.
EXAMPLE XIV
RNA-Guided NHEJ in 293T Cells
[0089] 293T cells were transfected with constructs indicated in the left panel of FIG. 11 . 4 days after nucleofection, NHEJ rate was measured by assessing genomic deletion and insertion rate at DSBs by deep sequencing. Panel 1: Deletion rate detected at targeting region. Red dash lines: boundary of T1 RNA targeting site; green dash lines: boundary of T2 RNA targeting site. The deletion incidence at each nucleotide position was plotted in black lines and the deletion rate as the percentage of reads carrying deletions was calculated. Panel 2: Insertion rate detected at targeting region. Red dash lines: boundary of T1 RNA targeting site; green dash lines: boundary of T2 RNA targeting site. The incidence of insertion at the genomic location where the first insertion junction was detected was plotted in black lines and the insertion rate as the percentage of reads carrying insertions was calculated. Panel 3: Deletion size distribution. The frequencies of different size deletions among the whole NHEJ population was plotted. Panel 4: insertion size distribution. The frequencies of different sizes insertions among the whole NHEJ population was plotted. 293T targeting by both gRNAs is efficient (10-24%) and sequence specific (as shown by the shift in position of the NHEJ deletion distributions).
EXAMPLE XV
HR at the Endogenous AAVS1 Locus Using Either a dsDNA Donor or a Short Oligonucleotide Donor
[0090] As shown in FIG. 12A , PCR screen (with reference to FIG. 2C ) confirmed that 21/24 randomly picked 293T clones were successfully targeted. As shown in FIG. 12B , similar PCR screen confirmed 3/7 randomly picked PGP1-iPS clones were also successfully targeted. As shown in FIG. 12C , short 90mer oligos could also effect robust targeting at the endogenous AAVS1 locus (shown here for K562 cells).
EXAMPLE XVI
Methodology for Multiplex Synthesis, Retrieval and U6 Expression Vector Cloning of Guide RNAs Targeting Genes in the Human Genome
[0091] A resource of about 190 k bioinformatically computed unique gRNA sites targeting ˜40.5% of all exons of genes in the human genome was generated. As shown in FIG. 13A , the gRNA target sites were incorporated into a 200 bp format that is compatible for multiplex synthesis on DNA arrays. Specifically, the design allows for (i) targeted retrieval of a specific or pools of gRNA targets from the DNA array oligonucleotide pool (through 3 sequential rounds of nested PCR as indicated in the figure schematic); and (ii) rapid cloning into a common expression vector which upon linearization using an AflII site serves as a recipient for Gibson assembly mediated incorporation of the gRNA insert fragment. As shown in FIG. 13B , the method was used to accomplish targeted retrieval of 10 unique gRNAs from a 12 k oligonucleotide pool synthesized by CustomArray Inc.
EXAMPLE XVII
CRISPR Mediated RNA-Guided Transcriptional Activation
[0092] The CRISPR-Cas system has an adaptive immune defense system in bacteria and functions to ‘cleave’ invading nucleic acids. According to one aspect, the CRISPR-CAS system is engineered to function in human cells, and to ‘cleave’ genomic DNA. This is achieved by a short guide RNA directing a Cas9 protein (which has nuclease function) to a target sequence complementary to the spacer in the guide RNA. The ability to ‘cleave’ DNA enables a host of applications related to genome editing, and also targeted genome regulation. Towards this, the Cas9 protein was mutated to make it nuclease-null by introducing mutations that are predicted to abrogate coupling to Mg2+ (known to be important for the nuclease functions of the RuvC-like and HNH-like domains): specifically, combinations of D10A, D839A, H840A and N863A mutations were introduced. The thus generated Cas9 nuclease-null protein (as confirmed by its ability to not cut DNA by sequencing analysis) and hereafter referred to as Cas9R-H-, was then coupled to a transcriptional activation domain, here VP64, enabling the CRISPR-cas system to function as a RNA guided transcription factor (see FIG. 14 ). The Cas9R-H-+VP64 fusion enables RNA-guided transcriptional activation at the two reporters shown. Specifically, both FACS analysis and immunofluorescence imaging demonstrates that the protein enables gRNA sequence specific targeting of the corresponding reporters, and furthermore, the resulting transcription activation as assayed by expression of a dTomato fluorescent protein was at levels similar to those induced by a convention TALE-VP64 fusion protein.
EXAMPLE XVIII
gRNA Sequence Flexibility and Applications Thereof
[0093] Flexibility of the gRNA scaffold sequence to designer sequence insertions was determined by systematically assaying for a range of the random sequence insertions on the 5′, middle and 3′ portions of the gRNA: specifically, 1 bp, 5 bp, 10 bp, 20 bp, and 40 bp inserts were made in the gRNA sequence at the 5′, middle, and 3′ ends of the gRNA (the exact positions of the insertion are highlighted in ‘red’ in FIG. 15 ). This gRNA was then tested for functionality by its ability to induce HR in a GFP reporter assay (as described herein). It is evident that gRNAs are flexible to sequence insertions on the 5′ and 3′ ends (as measured by retained HR inducing activity). Accordingly, aspects of the present disclosure are directed to tagging of small-molecule responsive RNA aptamers that may trigger onset of gRNA activity, or gRNA visualization. Additionally, aspects of the present disclosure are directed to tethering of ssDNA donors to gRNAs via hybridization, thus enabling coupling of genomic target cutting and immediate physical localization of repair template which can promote homologous recombination rates over error-prone non-homologous end-joining.
[0094] The following references identified in the Examples section by number are hereby incorporated by reference in their entireties for all purposes.
REFERENCES
[0000]
1. K. S. Makarova et al., Evolution and classification of the CRISPR-Cas systems. Nature reviews. Microbiology 9, 467 (June, 2011).
2. M. Jinek et al., A programmable dual-RNA-guided DNA endonuclease in adaptive bacterial immunity Science 337, 816 (Aug. 17, 2012).
3. P. Horvath, R. Barrangou, CRISPR/Cas, the immune system of bacteria and archaea. Science 327, 167 (Jan. 8, 2010).
4. H. Deveau et al., Phage response to CRISPR-encoded resistance in Streptococcus thermophilus. Journal of bacteriology 190, 1390 (February, 2008).
5. J. R. van der Ploeg, Analysis of CRISPR in Streptococcus mutans suggests frequent occurrence of acquired immunity against infection by M102-like bacteriophages. Microbiology 155, 1966 (June, 2009).
6. M. Rho, Y. W. Wu, H. Tang, T. G. Doak, Y. Ye, Diverse CRISPRs evolving in human microbiomes. PLoS genetics 8, e1002441 (2012).
7. D. T. Pride et al., Analysis of streptococcal CRISPRs from human saliva reveals substantial sequence diversity within and between subjects over time. Genome research 21, 126 (January, 2011).
8. G. Gasiunas, R. Barrangou, P. Horvath, V. Siksnys, Cas9-crRNA ribonucleoprotein complex mediates specific DNA cleavage for adaptive immunity in bacteria. Proceedings of the National Academy of Sciences of the United States of America 109, E2579 (Sep. 25, 2012).
9. R. Sapranauskas et al., The Streptococcus thermophilus CRISPR/Cas system provides immunity in Escherichia coli. Nucleic acids research 39, 9275 (November, 2011).
10. J. E. Garneau et al., The CRISPR/Cas bacterial immune system cleaves bacteriophage and plasmid DNA. Nature 468, 67 (Nov. 4, 2010).
11. K. M. Esvelt, J. C. Carlson, D. R. Liu, A system for the continuous directed evolution of biomolecules. Nature 472, 499 (Apr. 28, 2011).
12. R. Barrangou, P. Horvath, CRISPR: new horizons in phage resistance and strain identification. Annual review of food science and technology 3, 143 (2012).
13. B. Wiedenheft, S. H. Sternberg, J. A. Doudna, RNA-guided genetic silencing systems in bacteria and archaea. Nature 482, 331 (Feb. 16, 2012).
14. N. E. Sanjana et al., A transcription activator-like effector toolbox for genome engineering. Nature protocols 7, 171 (January, 2012).
15. W. J. Kent et al., The human genome browser at UCSC. Genome Res 12, 996 (June, 2002).
16. T. R. Dreszer et al., The UCSC Genome Browser database: extensions and updates 2011 . Nucleic Acids Res 40, D918 (January, 2012).
17. D. Karolchik et al., The UCSC Table Browser data retrieval tool. Nucleic Acids Res 32, D493 (Jan. 1, 2004).
18. A. R. Quinlan, I. M. Hall, BEDTools: a flexible suite of utilities for comparing genomic features. Bioinformatics 26, 841 (Mar. 15, 2010).
19. B. Langmead, C. Trapnell, M. Pop, S. L. Salzberg, Ultrafast and memory-efficient alignment of short DNA sequences to the human genome. Genome Biol 10, R25 (2009).
20. R. Lorenz et al., ViennaRNA Package 2.0 . Algorithms for molecular biology: AMB 6, 26 (2011).
21. D. H. Mathews, J. Sabina, M. Zuker, D. H. Turner, Expanded sequence dependence of thermodynamic parameters improves prediction of RNA secondary structure. Journal of molecular biology 288, 911 (May 21, 1999).
22. R. E. Thurman et al., The accessible chromatin landscape of the human genome. Nature 489, 75 (Sep. 6, 2012).
23. S. Kosuri et al., Scalable gene synthesis by selective amplification of DNA pools from high-fidelity microchips. Nature biotechnology 28, 1295 (December, 2010).
24. Q. Xu, M. R. Schlabach, G. J. Hannon, S. J. Elledge, Design of 240,000 orthogonal 25mer DNA barcode probes. Proceedings of the National Academy of Sciences of the United States of America 106, 2289 (Feb. 17, 2009). | A method of altering a eukaryotic cell is provided including transfecting the eukaryotic cell with a nucleic acid encoding RNA complementary to genomic DNA of the eukaryotic cell, transfecting the eukaryotic cell with a nucleic acid encoding an enzyme that interacts with the RNA and cleaves the genomic DNA in a site specific manner, wherein the cell expresses the RNA and the enzyme, the RNA binds to complementary genomic DNA and the enzyme cleaves the genomic DNA in a site specific manner. | 2 |
BACKGROUND OF THE INVENTION
This invention relates to plasmin. More particularly, this invention relates to a synthetic substrate for the colorimetric or fluorometric assay of plasmin.
In man, fibrinolysis is controlled and regulated by the activity of the plasminogen-plasmin proteolytic enzyme system. Plasminogen, the naturally occurring precursor, is converted to plasmin by naturally occurring plasminogen activators or by kinases, such as streptokinase, urokinase, and staphylokinase. Plasminogen, normally present in all body fluids and secretions, has its highest concentration in plasma.
In the prior art, plasmin assays typically involved protein digestion systems, with casein being the most commonly used protein. Although such systems were satisfactory to a limited extent, a number of disadvantages are inherent in such systems. In general, protein digestion systems require at least about 15 minutes per assay; during this period of time, it is not possible to measure kinetic changes (e.g., the instantaneous formation of plasmin). Furthermore, it is not possible to evaluate the presence of plasminogen activators. Additionally, at high plasmin levels, turbid solutions often result. More importantly, protein digestion systems are not entirely reproducible from one source of protein to another (hence, from one laboratory to another). Protein digestion systems require the use of an ultraviolet spectrophotometer, which poses problems in determining the appropriate blank since digestion of serum proteins in the blank contributes to ultraviolet absorption. Furthermore, plasmin content cannot be defined in the traditional manner of micromoles of substrate hydrolyzed per unit of time. That is, the hydrolysis is not linear with enzymatic activity; an arbitrary curve is obtained which must be defined by a standard enzyme solution of limited availability.
Attempts to overcome the disadvantages of protein digestion systems in the assay of plasmin have led to the preparation of a number of synthetic substrates. Examples of such synthetic substrates include, among others, the following: ethyl p-guanidinobenzoate hydrochloride and p-nitrophenyl p'-guanidinobenzoate hydrochloride [T. Chase, Jr. and E. Shaw, Biochemistry, 8, 2212 (1969)]; N-(p-carboxybenzyl)pyridinium bromide p-nitrophenyl ester [J. M. Sodetz and F. J. Castellino, Biochemistry, 11, 3167 (1972)]; N.sup.α -tosyl-L-arginine methyl, ethyl, and butyl esters, ethyl esters of glycine, L-lysine, DL-valine, L-leucine, L-isoleucine, DL-methionine, L-tyrosine, and DL-tryptophan, N.sup.α -benzoyl-L-arginine ethyl ester, N.sup.α -acetyl-L-tyrosine ethyl ester, N.sup.α -acetyl-DL-tryptophan ethyl ester, and N.sup.α -acetyl-DL-methionine ethyl ester [W. Troll, et al., J. Biol. Chem., 208, 85 (1954)]; L-arginine methyl ester, L-lysine methyl ester, N.sup.α -acetyl-L-lysine methyl ester, N.sup.α -benzoyl-L-arginine methyl ester, N.sup.α -carbobenzoxy-L-lysine methyl ester, N.sup.α -tosyl-L-lysine methyl ester, N.sup.α -carbobenzoxy-L-arginine methyl ester, and N.sup.α -acetyl-L-arginine methyl ester [S. Sherry, et al., Thromb. Diath. Haemorrh., 34, 20 (1975)]; N.sup.α -benzyloxycarbonyl-L-lysine p-nitrophenyl ester [R. M. Silverstein, Thrombos. Res., 3, 729 (1973)]; N.sup.α -methyl-N.sup.α -tosyl-L-lysine β-naphthol ester [P. H. Bell, et al., Anal. Biochem., 61, 200 (1974)]; and N.sup.α -benzoylphenylalanine-valine-arginine-p-nitroanilide [P. Friberger, et al., Thromb. Diath. Haemorrh., 34, 321 (1975)]. The usual problems with most such synthetic substrates include, among others, a slow rate of reaction, rapid spontaneous hydrolysis, and difficulty in measuring the hydrolysis products.
It should be noted that some tripeptides are known which have the same amino acid sequences as the tripeptidyl portion of some of the substrates of the present invention. Examples of such known tripeptides include the following: N.sup.α -trityl-glycine-glycine-N.sup.ε -benzyloxycarbonyl-L-lysine benzyl ester, glycine-glycine-L-lysine, glycine-glycine-N.sup.ε -benzyloxycarbonyl-L-lysine benzyl ester hydrochloride, and N.sup.α -benzyloxycarbonyl-glycine-glycine-N.sup.ε -benzyloxycarbonyl-L-lysine benzyl ester and hydrazide [O. Abe, et al., Bull. Chem. Soc. Japan, 40, 1945 (1967)]; N.sup.α -formyl-L-phenylalanine-L-leucine-N.sup.ε -t-butyloxycarbonyl-L-lysine and methyl ester thereof [L. V. Ionova and E. A. Morozova, J. Gen. Chem. USSR, 34, 407 (1964)]; N.sup.α -benzyloxycarbonyl-glycine-glycine-L-lysine and diacetate monohydrate thereof [K. Suzuki and T. Abiko, Chem. Pharm. Bull. (Tokyo), 16, 1997 (1968)]; and O-benzyl-N.sup.α -benzyloxycarbonyl-L-tyrosine-L-serine-N.sup.ε -t-butyloxycarbonyl-L-lysine methyl ester, N.sup.α,O-bis(benzyloxycarbonyl)-L-tyrosine-L-serine-N.sup.ε -t-butyloxycarbonyl-L-lysine methyl ester, N.sup.α -benzyloxycarbonyl-L-tyrosine-L-serine-N.sup.ε -t-butyloxycarbonyl-L-lysine methyl ester, and L-tyrosine-L-serine-N.sup.ε -t-butyloxycarbonyl-L-lysine methyl ester [A. A. Costopanagiotis, et al., J. Org. Chem., 33, 1261 (1968)].
The assay of plasmin by the plasmin-catalyzed hydrolysis of a given substrate to give one or more identifiable and measurable products is, of course, known in the art. The substrates of the present invention, however, can be used in such known procedure or procedures related thereto without the disadvantages attending the known, prior art substrates.
SUMMARY OF THE INVENTION
It therefore is an object of the present invention to provide a substrate for the assay of plasmin which eliminates or minimizes many of the problems associated with prior art protein digestion systems.
A further object of the present invention is to provide a substrate for the assay of plasmin which eliminates or minimizes many of the problems associated with prior art synthetic plasmin substrates.
Yet another object is to provide a sensitive, stable, versatile, substrate for the assay of plasmin which can be used with either colorimetric or fluorometric techniques. These and other objects will be apparent to those skilled in the art from a consideration of the specification and claims which follow.
In accordance with the present invention, a plasmin assay substrate is provided, which substrate is a tripeptidyl-4-methoxy-2-naphthylamide having the formula, ##STR2## in which R 1 and R 2 independently are hydrogen, alkyl, hydroxyalkyl, mercaptoalkyl, methylthioalkyl, benzyl, or hydroxybenzyl, with the proviso that at least one of R 1 and R 2 must be other than benzyl or hydroxybenzyl; and the acid addition salts thereof in which the acid is inorganic or C 1 -C 2 carboxylic.
It will be understood by those skilled in the art that reference to the assay of plasmin also includes the assay of plasminogen, since plasminogen is readily converted to plasmin by a small amount of activator, such as streptokinase, urokinase, and the like.
The substrates of the present invention are useful for either routine clinical plasmin or plasminogen assays or kinetic studies.
DETAILED DESCRIPTION OF THE INVENTION
As is well known in the art, all of the naturally-occurring amino acids, with the exception of glycine, are in the L form. To indicate this in the above-described general formula, the amino group (as a carboxylic acid amide) of each amino acid is placed above the carbon chain when the carbon chain is written horizontally with the carboxylic acid group (as the carboxylic acid amide) at the right. When reference is made herein to a specific tripeptidyl-4-methoxy-2-naphthylamide, the Tentative Rules of IUPAC-IUB Commission on Biochemical Nomenclature, Abbreviated Designation of Amino Acid Derivatives and Peptides, will be followed [see, e.g., J. Biol. Chem., 241, 2491 (1966)]; the 4-methoxy-2-naphthylamide portion will be indicated by the abbreviation, --MNA, and the N-blocking group, benzyloxycarbonyl, will be indicated by the abbreviation, Z-. In accordance with nomenclature already established by those skilled in the art, the peptidyl amides of 4-methoxy-naphthyl amine disclosed herein are named as tripeptidyl-4-methoxy-2-naphthylamides.
As already stated, R 1 and R 2 independently are hydrogen, alkyl, hydroxyalkyl, mercaptoalkyl, methylthioalkyl, benzyl, or hydroxybenzyl, with the proviso that at least one of R 1 and R 2 must be other than benzyl or hydroxybenzyl. Preferably, R 1 and R 2 independently are hydrogen or alkyl. More preferably, R 1 and R 2 both are either hydrogen or alkyl, and most preferably are alkyl. Examples of amino acids, other than lysine, which can be employed include, among others, glycine, alanine, valine, leucine, isoleucine, serine, threonine, cysteine, methionine, phenylalanine, and tyrosine.
Examples of specific tripeptidyl-4-methoxy-2-naphthylamides coming within the general formula described hereinabove include, among others, the following:
Z-gly-Gly-L-Lys-MNA,
Z-l-ala-L-Ala-L-Lys-MNA,
Z-l-val-L-Val-L-Lys-MNA,
Z-l-leu-L-Leu-L-Lys-MNA,
Z-l-ile-L-Ile-L-Lys-MNA,
Z-l-ser-L-Ser-L-Lys-MNA,
Z-l-thr-L-Thr-L-Lys-MNA,
Z-l-cys-L-Cys-L-Lys-MNA,
Z-l-met-L-Met-L-Lys-MNA,
Z-gly-L-Ala-L-Lys-MNA,
Z-gly-L-Cys-L-Lys-MNA,
Z-l-ala-Gly-L-Lys-MNA,
Z-l-ala-L-Tyr-L-Lys-MNA,
Z-l-val-L-Ser-L-Lys-MNA,
Z-l-leu-L-Met-L-Lys-MNA,
Z-l-ile-L-Ala-L-Lys-MNA,
Z-l-ile-L-Thr-L-Lys-MNA,
Z-l-ser-L-Ala-L-Lys-MNA,
Z-l-ser-L-Phe-L-Lys-MNA,
Z-l-thr-L-Ile-L-Lys-MNA,
Z-l-cys-L-Val-L-Lys-MNA,
Z-l-met-L-Cys-L-Lys-MNA,
Z-l-met-L-Tyr-L-Lys-MNA,
Z-l-phe-l-Thr-L-Lys-MNA,
Z-l-tyr-Gly-L-Lys-MNA,
Z-l-tyr-L-Met-L-Lys-MNA,
and the like.
Examples of the preferred compounds include, among others, Z-L-Ala-L-Ala-L-Lys-MNA, Z-L-Val-L-Val-L-Lys-MNA, Z-L-Leu-L-Leu-L-Lys-MNA, Z-L-Ile-L-Ile-L-Lys-MNA, Z-Gly-Gly-L-Lys-MNA, Z-Gly-L-Ala-L-Lys-MNA, Z-Gly-L-Ile-L-Lys-MNA, Z-L-Ala-Gly-L-Lys-MNA, Z-L-Ala-L-Leu-L-Lys-MNA, Z-L-Val-L-Ala-L-Lys-MNA, Z-L-Val-L-Ile-L-Lys-MNA, Z-L-Leu-Gly-L-Lys-MNA, Z-L-Leu-L-Val-L-Lys-MNA, Z-L-Leu-L-Ile-l-Lys-MNA, Z-L-Ile-L-Ala-L-Lys-MNA, Z-L-Ile-L-Leu-L-Lys-MNA, and the like. Examples of the more preferred compounds include, among others, Z-L-Ala-L-Ala-L-Lys-MNA, Z-L-Val-L-Val-L-Lys-MNA, Z-L-Leu-L-Leu-L-Lys-MNA, Z-L-Ile-L-Ile-L-Lys-MNA, Z-Gly-Gly-L-Lys-MNA, and the like. Examples of the most preferred compounds include, among others, Z-L-Ala-L-Ala-L-Lys-MNA, Z-L-Val-L-Val-L-Lys-MNA, Z-L-Leu-L-Leu-L-Lys-MNA, Z-L-Ile-L-Ile-L-Lys-MNA, and the like.
The tripeptidyl-4-methoxy-2-naphthylamide substrates provided by the present invention are prepared according to standard peptide chemistry procedures. The following examples are representative of such procedures:
EXAMPLE 1
Preparation of N.sup.α -Z-N.sup.ε -BOC-L-LYS-MNA
A mixture of 28.1 g. (50 mmol) of N.sup.α -Z-N.sup.ε -Boc-L-Lys as the N,N-dicyclohexylamine salt [prepared by the method of L. Zervas and C. Hamalidis, J. Amer. Chem. Soc., 87, 99 (1965)] and 17.25 g. (50 mmol) of 4-methoxy-2-naphthylamine p-toluenesulfonate [prepared by the procedure of E. L. Smithwick, Jr. and R. T. Shuman, synthesis, 8, 581 (1974)] in 100 ml. of N,N-dimethylformamide was agitated under a nitrogen atmosphere for 30 minutes. To the reaction mixture, cooled to 0° C., were added 6.75 g. (50 mmol) of 1-hydroxybenzotriazole and 10.3 g. (50 mmol) of N,N'-dicyclohexylcarbodiimide. After agitating for 2 hours at 0° C., the reaction mixture then was stirred at ambient temperature for 24 hours. The reaction mixture was cooled to 0° C. and the precipitated N,N'-dicyclohexylurea was removed by filtration. The filtrate was distilled under reduced pressure; the residue was triturated with 1 N aqueous sodium bicarbonate solution, then recrystallized three times from hot ethanol, giving 15.3 g. (58 percent) of N.sup.α -Z-N.sup.ε -Boc-L-Lys-MNA, m.p. 157°-159° C. The following elemental microanalysis was obtained:
Calculated for C 30 H 37 N 3 O 6 : C, 67.27; H, 6.96; N, 7.84
Found: C, 67.25; H, 6.74; N, 7.62.
EXAMPLE 2
Preparation of N.sup.α -Z-L-Ala-L-Ala-N.sup.ε -Boc-L-Lys-MNA
N.sup.α -Z-N.sup.ε -Boc-L-Lys-MNA (4.7 g., 8.8 mmol) was dissolved in 20 ml. of N,N-dimethylformamide and 50 ml. of ethanol, and subjected to hydrogenolysis over 1 g. of palladium on carbon at 1 atmosphere hydrogen pressure for 4 hours. The reaction mixture was filtered. The filtrate was concentrated under reduced pressure and the residue was dissolved in 30 ml. of N,N-dimethylformamide. To the resulting solution were added 8.8 mmol of N.sup.α -Z-L-Ala-L-Ala [prepared by the procedure of M. Goodman, et al., Bioorg. Chem., 1, 294 (1971)], 1.19 g. (8.8 mmol) of 1-hydroxybenzotriazole, and 1.81 g. (8.8 mmol) of N,N'-dicyclohexylcarbodiimide. After standing 48 hours at 4° C., the reaction mixture was filtered to remove precipitated N,N'-dicyclohexylurea, and the filtrate was evaporated under reduced pressure. Trituration of the residue with 1 N sodium bicarbonate, followed by two recrystallizations from N,N-dimethylformamide/ethanol gave 3.5 g. (60 percent) of N.sup.α -Z-L-Ala-L-Ala-N.sup.ε -Boc-L-Lys-MNA, m.p. 213°-214° C. The following elemental microanalysis was obtained:
Calculated for C 36 H 47 N 5 O 8 : C, 63.79; H, 6.99; N, 10.33
Found: C, 64.05; H, 6.51; N, 10.63.
EXAMPLE 3
Preparation of N.sup.α -Z-L-Ala-L-Ala-L-Lys-MNA Acetate
A mixture of 3.0 g. (4.43 mmol) of N.sup.α -Z-L-Ala-L-Ala-N.sup.ε -Boc-L-Lys-MNA and 2.5 g. (3 meq) of p-toluene-sulfonic acid monohydrate in 100 ml. of acetonitrile containing 10 percent triethylsilane was agitated at ambient temperature for 8 hours. The reaction mixture was diluted with diethyl ether and the resulting precipitate was isolated by filtration. The precipitate was redissolved in N,N-dimethylformamide and extracted into chloroform after neutralization of the N,N-dimethylformamide solution with aqueous base. The chloroform was dried over anhydrous magnesium sulfate and evaporated in vacuo to give a residue which was lyophilized from acetic acid. The resulting residue then was dissolved in ethanol, treated with activated charcoal, and the product precipitated with diethyl ether, giving 1.5 g. (53 percent) of N.sup.α -Z-L-Ala-L-Ala-L-Lys-MNA acetate. The following amino acid analysis was obtained:
Ala, 2.03; Lys, 0.97 (92 percent recovery).
EXAMPLE 4
Preparation of N.sup.α -Z-Gly-Gly-N.sup.ε -Boc-L-Lys-MNA
N.sup.α -Z-Gly-Gly-N.sup.ε -Boc-L-Lys-MNA was prepared from Z-Gly-Gly and N.sup.ε -Boc-L-Lys-MNA by the procedure of Example 2, then recrystallized from ethanol; m.p. 145°-147° C. The following elemental microanalysis was obtained:
Calculated for C 34 H 43 N 5 O 8 : C, 62.85; H, 6.67; N, 10.78
Found: C, 62.62; H, 6.42; N, 10.56
EXAMPLE 5
Preparation of N.sup.α -Z-Gly-Gly-L-Lys-MNA Acetate
N.sup.α -Z-Gly-Gly-L-Lys-MNA acetate was prepared from the compound of Example 4 by the procedure of Example 3. The following amino acid analysis was obtained:
Gly, 1.98; Lys, 1.02 (74 percent recovery).
As already stated, the substrates of the present invention are useful for the determination of plasmin. Plasminogen, the plasmin precursor, normally has its highest concentration in plasma, which concentration depends upon the physical well-being of the individual. Since plasminogen concentration, and, consequently, plasmin concentration, are altered by various fibrinolytic disorders, the monitoring of plasmin concentration in plasma provides a means for the detection of fibrinolytic disorders and for monitoring the clinical treatment of such disorders as is well known in the art.
In general, the plasmin assay employing the substrates of the present invention is carried out in accordance with known procedures. Briefly, from about 0.1 ml. to about 0.5 ml., preferably from about 0.1 to about 0.2 ml., of blood plasma is diluted to a volume of 1.5 ml. with 0.05 molar tris(hydroxymethyl)aminomethane (Tris) buffer at pH 8.0. If plasminogen is to be determined, 500-1000 International Units of streptokinase is added to the blood plasma sample before diluting with the Tris buffer. To the diluted blood plasma solution is added 1.0 ml. of an aqueous substrate solution containing 1.2 mg. (2 mM) of substrate per ml. of water. The resulting reaction mixture then is incubated, typically for 15 minutes at 37° C. For a fluorometric assay, the reaction solution is transferred immediately after incubation to a fluorometer and light of 360 nm wavelength is used for excitation; the relative intensity of fluorescence at 420 nm is measured. For colorimetric assay, the reaction is stopped after incubation by the addition of 0.1 ml. 1.0 N aqueous hydrochloric acid solution. To the reaction solution then is added 1 ml. of fast blue B dye solution containing 1 mg. of dye. Color is allowed to develop, typically for 5 minutes at ambient temperature, and absorbance then is measured at 520 nm. If desired, instantaneous measurements of plasmin activity can be made by transferring the reaction mixture, without incubation, immediately to a fluorometer and recording the increase of fluorescence with time.
The results obtained from either the colorimetric or fluorometric assay are compared with plasmin standard curves which are prepared in accordance with known procedures. The plasmin standard curves employed to obtain the data reported herein were made with "First British Standard for Plasmin, Human, 72/739," obtained from the National Institute for Biological Standards and Control, Holly Hill, Hampstead, London. Fast blue B dye was purchased from K and K Laboratories, Plainview, N.Y.
Colorimetric measurements were made with Gilford Spectrophotometers, either Model 300-N or Model 240 with a digital absorbance meter (Model 410) and recorder (Model 6040). Absorption spectra were determined with a Cary 14 Recording Spectrophotometer. Fluorescence measurements were made with an Aminco-Bowman Spectrophotofluorometer with a Xenon lamp ratio photometer and a Shimadzu recorder, Model R-101.
The use of the above-described procedure to assay plasmin and plasminogen is ilustrated by the data in Table 1. Such data were obtained by the preferred 15-minute colorimetric assay, using as substrate Z-L-Ala-L-Ala-L-Lys-MNA. The streptokinase, when used, was added to the blood plasma sample, prepared in the usual way, prior to dilution with Tris buffer. While any plasmin already present will be measured along with plasmin derived from plasminogen, it usually is not necessary to correct the plasminogen value for plasmin when normal subjects are used, since the blood plasma of such subjects typically contains negligible amounts of plasmin.
Table 1______________________________________Colorimetric Plasminogen and Plasmin Assays of Blood Plasmafrom Normal Subjects, Using Z-L-Ala-L-Ala-L-Lys-MNAAs Substrate______________________________________ Plas- Plasma Units minogen, Plasmin,Sample Vol., ml. SK.sup.a A.sub.520 Units/ml. Units/ml.______________________________________A. Human Plasma Patient 1 0.1 1000 0.12 1.2 -- Patient 2 0.1 1000 0.18 1.8 -- Patient 3 0.2 1000 0.36 1.8 --B. Dog Plasma Sample 1 0.1 500 0.096 1.0 -- Sample 2 0.1 500 0.085 0.8 -- Sample 2 0.1 0 0.005 -- <0.05______________________________________ .sup.a SK=Streptokinase
All enzyme contents are expressed in the internationally defined units which are well known to those skilled in the art. It may be noted from Table 1 that the approximate lower limit of detection of plasmin is 0.05 unit/ml. The limit is to a large extent the result of instrumental error at low absorbance values. Thus, when plasmin content is known to be low, larger plasma samples should be employed.
The colored compound formed by the reaction of 4-methoxy-2-naphthylamine with fast blue B dye has a strong absorption band at 520 nm. The molar absorption coefficient, ε, decreases with time and exposure to light, and concentrated solutions, i,e., solutions giving an absorbance through a 1 cm. cell greater than about 1.0, fade and frequently form a precipitate. Fading and precipitation are accelerated by exposure to light. The maximum value for ε obtained by using a dilute solution and development of color in the dark, is about 33,000 M -1 cm -1 . Although maximum color is not achieved in light, it is more convenient to let the color develop under ordinary room illumination and to read absorption values consistently five minutes after adding dye to the assay sample. Under such conditions, the value for ε is about 27,000 M -1 cm -1 . Except as discussed above, the value for ε in either case in constant for any given amine-dye coupling product and is independent of the tripeptidyl moiety.
In general, the assay can be carried out at a pH of from about 7 to about 10. The optimum pH, however, is from about 8 to about 8.5, with pH 8.0 being most preferred.
The relationship of absorbance or intensity of fluorescence to plasmin concentration typically is linear, provided that plasmin concentration is less than about 1.0 unit of plasmin per assay volume (typically about 3.5 ml.) and the incubation time is no greater than about 15 minutes. The linearity of such relationship is preserved, however, at longer incubation times, e.g., up to about 60 minutes, when plasmin concentration is less than about 0.2 unit plasmin per assay volume. Accordingly, it is preferred to use sample sizes which will provide less than about 1 unit of plasmin per assay volume and incubation periods of 15 minutes.
In order to study the effectiveness of the substrates provided by the present invention, colorimetric plasmin assays were run using solutions containing known quantities of plasmin in place of blood plasma samples. Plasmin was obtained by converting plasminogen to plasmin by the addition of either streptokinase or urokinase to a plasminogen-containing solution. The plasminogen was prepared from outdated human plasma by batch absorption on lysine-Sepharose, entirely under cold conditions; see R. J. Walther, et al., J. Biol. Chem., 249 1173 (1974), and D. K. McClintock, et al., Biochemistry, 13, 5334 (1974). Steptokinase was obtained as Varidase from Lederle, Pearl River, N.Y., and urokinase was obtained from Leo Pharmaceutical Products, Denmark. The colorimetric assay results obtained with such known plasmin solutions are summarized in Table 2.
TABLE 2______________________________________Hydrolysis of Plasmin Substrates Units nmoles HydrolyzedSubstrate Plasmin .sup.A 520 /unit plasmin______________________________________Z-Gly-Gly-L-Lys-MNA 10 1.2 16Z-L-Ala-L-Ala-L-Lys-MNA 2 1.8 120______________________________________
Plasmin content is expressed in the internationally defined units which are well known to those skilled in the art. From the last or right-hand column of Table 2, it is seen that of the two substrates tested, Z-L-Ala-L-Ala-L-Lys-MNA is the more sensitive toward hydrolysis by plasmin. Thus, such substrate will be the more effective for determinations involving low plasmin concentrations.
While the substrates of the present invention are not specific for plasmin, such substrates do possess a sufficient degree of specificity for plasmin that the plasmin assay can be carried out in the presence of small amounts of other, related enzymes. Such specificity is shown in Table 3, which summarizes the hydrolysis, determined by the colorimetric procedure, of Z-L-Ala-L-Ala-L-Lys-MNA by plasmin and several other proteinases. Trypsin was obtained from Worthington Biochemical Corporation, Freehold, New Jersey; thrombin was purchased from Parke, Davis, and Company, Detroit, Michigan; and procine acrosin was obtained from Dr. P. J. Burck of the Lilly Research Laboratories, Indianapolis, Ind. Except as footnoted in Table 2, all amounts of enzymes are expressed in internationally defined units.
TABLE 3______________________________________Hydrolysis of Z-L-Ala-L-Ala-L-Lys-MNA by Proteinases mole Units Units Per Hydrolyzed Per nmoles mole of per mole ofEnzyme Test Hydrolyzed Enzyme Enzyme______________________________________Thrombin 100 74 8.5 × 10.sup.10 63Acrosin 400 23 1.2 × 10.sup.12 69Urokinase 400 9 3.8 × 10.sup.12 86Plasmin 1 120 3.4 × 10.sup.9 340Trypsin 2.sup.a 290 24 × 10.sup.9 3500______________________________________ .sup.a 1 unit - 1 μg
The data in both Tables 2 and 3 were obtained in accordance with the preferred 15-minute colorimetric plasmin assay described hereinbefore. As already stated, Table 3 is an illustration of the relative order of specificity of several proteinases toward Z-L-Ala-L-Ala-L-Lys-MNA, one of the substrates of the present invention. The data in Table 3 were obtained by subjecting the substrate to hydrolysis by each enzyme. The nmoles of substrate hydrolyzed in each case were determined from the absorbance value in the usual manner. The nmoles of substrate hydrolyzed then were converted to moles of substrate hydrolyzed per mole of enzyme, using the generally accepted value, taken from the literature, for the number of units per mole of each enzyme. The relatively low values for moles of substrate hydrolyzed per mole of enzyme for thrombin, acrosin, and urokinase demonstrate that the presence of small amounts of such enzymes will not significantly interfer with the plasmin assay. The enzyme trypsin, however, is known to be both potent and of a broad specificity, requiring only the presence of a basic amino acid. Therefore, the rapid hydrolysis of trypsin of the substrate of Table 2 was expected. Trypsin, however, normally is not present in the blood and hence presents no problem in the plasmin assay.
The substrates of the present invention provide the means for plasmin assays which are reproducible, sensitive, and convenient. The sensitivity of the assay results more from the sensitivity in detecting hydrolysis than from the kinetics of the reaction; hence, blank corrections for the substrates of the present invention are negligible. The high molar absorptivity of the dye complex and the intensity of the fluorescence facilitate detection of small amounts of hydrolysis product.
It should be pointed out that substrate solubility must be taken into consideration when carrying out plasmin assays with such substrates. The assay as described uses a substrate concentration of about 2 mM. This does not cause problems so long as the substrate concentration is consistent and assays are restricted to the linear part of the rate curve. If necessary, the concentration of such substrate can be doubled, thereby approaching the limits of solubility of the substrate, to obtain a slight increase in sensitivity and an extension of the range of the linearity. Beyond that, substrate insolubility becomes a problem. The substrate also is less soluble in buffer of ionic strength greater than 0.1. Protein also precipitates the substrate, but the assay has been used to measure serum plasma levels without difficulty.
Since substrate solubility can be important, it often is desirable to employ an acid addition salt of the substrate in order to improve substrate solubility. The term "acid addition salt" is well known to those skilled in the art. In general, such a salt is formed by reacting in a mutual solvent a stoichiometric amount of a suitable acid with a substrate of the present invention, although an excess of the acid can be used where the acid is sufficiently volatile. Normally, the choice of salt-forming acid is not critical. Representative and suitable acids include, among others, the following: hydrochloric, hydrobromic, hydriodic, sulfuric, nitric, phosphoric, formic, acetic, and the like.
The chief advantage of the substrates of the present invention are in the versatility of the plasmin assay employing such substrates. A large number of routine assays are easily handled by the colorimetric procedure. Very sensitive measurements can be made by fluorometry. Kinetic analyses of plasmin activity can be made to avoid problems of enzyme stability. The substrates of the present invention also are useful in the identification of enzyme activity on electropherograms, using either fluorometric or colorimetric techniques. | The proteinase plasmin is assayed either colorimetrically or fluorometrically with a tripeptidyl-4-methoxy-2-naphthylamide substrate having the following general formula: ##STR1## The substrate is useful for either routine clinical assays or kinetic studies. | 2 |
BACKGROUND OF THE INVENTION
Field of the Invention
The invention relates to an apparatus for supplying power to a long stator winding which has a plurality of winding sections, having an energy source, a supply line which is connected to the energy source, section switches which are connected to the supply line and each has a connection for connection to in each case one winding section.
One such apparatus is already known from the prior art. By way of example, apparatuses are described for supplying power to a magnetic levitation railroad and have been implemented, for example, in Shanghai, China, in which the drive is not arranged in the rail vehicle, which moves at the speed of travel. Instead of this, the drive is accommodated in the track and comprises a long stator motor, which is characterized essentially by the long stator winding.
FIG. 1 schematically illustrates an apparatus, which is known from the prior art, for supplying power to a magnetic levitation railroad. As can be seen, the long stator winding 1 is subdivided into a plurality of winding sections 2 , with the winding sections 2 being directly connected to one another in the track, which is not illustrated in any more detail in the figure. The input side of each winding section 2 is connected to a section switch 3 , and each winding section 2 is connected to a star-point switch 4 at its end remote from the section switch 3 . In its closed position, the star-point switch 4 connects the winding section 2 to a star point 5 . The section switch 3 is in contrast used for connecting the winding section 2 which is in each case associated with it to a power supply cable 6 , which is connected to a converter, which is not illustrated in the figure, as an energy source. The long stator winding 1 has to be subdivided into winding sections 2 since, otherwise, the entire long stator winding 1 would have to be excited over its entire length, resulting in high energy losses. When one section switch 3 and one star-point switch 4 are switched on at the same time, this in contrast leads to excitation of a selected winding section 2 of limited length, in which a magnetic traveling field is produced as a function of the converter drive. The traveling field interacts with supporting and guide magnets which are arranged on the vehicle side, resulting in the vehicle being driven electrodynamically. As soon as the driven vehicle is no longer located above the winding section 2 , the section switch 3 and the star-point switch 4 are opened.
In addition to its resistive/inductive impedance with respect to the ambient potential, each winding section 2 also has a capacitive impedance. A capacitance 7 is therefore schematically associated with each winding section 2 , in each case, in FIG. 1 . A corresponding situation applies to the supply line 6 , whose capacitance 8 is distributed over its entire length. According to the prior art, one winding section 2 has essentially until now been connected to the supply line 6 . The respectively connected winding section 2 represents a highly inductive load. This therefore results in a phase shift between the drive current and the drive voltage, resulting in the production of reactive power. This inductive reactive power cannot be compensated for adequately by the capacitance 8 of the supply line 6 and the capacitance 7 of the respectively connected winding section 2 , thus resulting, according to the prior art, in an additional load on the drive system, because of the reactive power. This reactive power can be actively compensated for in some converters by expedient drive regulation, although this places a load on the drive system.
BRIEF SUMMARY OF THE INVENTION
The object of the invention is therefore to provide an apparatus of the type mentioned initially, which allows the reactive power to be compensated for independently of the energy source regulation.
The invention achieves this object by means for reactive power compensation (power factor correction), which are designed to adjust the impedance of the apparatus.
According to the invention, the impedance of the power supply apparatus according to the invention is adjusted such that the reactive power created when driving is compensated for in the desired manner. For the purposes of the invention, components of the apparatus which are provided in any case are connected with a capacitive effect, in order to compensate for the inductively acting winding section 2 that is connected. This reduces the load on the energy source, that is to say normally a converter which feeds electrical power into the supply conductor. According to the invention, the converter can therefore be regulated independently of the respective impedance of the apparatus when driving, and is therefore more efficient.
According to one preferred refinement of the invention, the means for power factor correction have a control unit which is designed to open or close at least some of the section switches. This results in the impedance of the apparatus being influenced by the winding sections of the long stator, which are provided in any case. The solution is therefore extremely cost-effective. For example, if the capacitive impedance of the overall apparatus is intended to be increased, the control unit closes a number of section switches, which are connected to an open star-point switch via the associated winding section, until the sum of the capacitances of the winding sections which are connected in this way, plus the capacitive impedance of the supply line and of the winding section 3 through which current is being passed, corresponds approximately to the inductive impedance of the winding section through which current is being passed.
The control unit is advantageously connected to measurement sensors which produce measurement signals and has internal control logic which is designed to open or close the section switches which are connected to the control unit, as a function of adjustment parameters and on the basis of the measurement signals. According to this advantageous refinement, the reactive current component of the apparatus during operation, that is to say while power is being supplied, is determined on the basis of the measurement sensors. By way of example, the measurement sensors are current and voltage measurement devices, which detect the current and the voltage in each phase of the supply conductor and determine said reactive current component in an already known manner on the basis of these measurement signals. Furthermore, the control unit has adjustment parameters which, for example, contain information on the respective magnitude of the capacitive impedance of the remaining winding sections, through which no current is currently being passed, and the magnitude of the capacitive impedance of the supply conductor. This data or these adjustment parameters allows or allow the reactive power to be compensated for as accurately as possible, by means of a simple computation rule.
At least one additional conductor switching unit, which is connected to the control unit, is expediently provided, wherein each additional conductor switching unit is connected to an additional conductor whose impedance is available to the control unit as an adjustment parameter. According to this advantageous further development, the variability and therefore the matching accuracy of the impedance to the respective requirements are enhanced.
Furthermore, a reactance unit, which is connected to the supply power, is advantageous in order to further improve the variability. By way of example, an additional capacitor or else a coil may be used as the reactance unit. However, in contrast to this, active reactance units are also provided, which have a plurality of capacitive impedances, such as condensers, and a switching unit. By way of example, the switching unit is connected to the control unit, as a result of which said capacitive impedance can be connected in its entirety or in parts in parallel with the winding section through which current is in each case being passed.
In other words, by way of example, the reactance unit can be connected via a reactance switch to the supply unit, in parallel with the winding section through which current is being passed, with the reactance switching unit in turn being connected to the control unit.
It should be mentioned at this point that any design of switching units may be used for the purposes of the invention. For example, both mechanical and semiconductor switches may be used for the purposes of the invention.
Further expedient refinements and advantages of the invention are the subject matter of the following description of exemplary embodiments of the invention with reference to the figures of the drawing, in which the same reference symbols refer to components having the same effect, and in which:
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING.
FIG. 1 shows a schematic illustration of an apparatus according to the prior art,
FIG. 2 shows a schematic illustration of one exemplary embodiment of the apparatus according to the invention,
FIG. 3 shows a further exemplary embodiment of the apparatus according to the invention, and
FIG. 4 shows a further exemplary embodiment of the apparatus according to the invention.
DESCRIPTION OF THE INVENTION
FIG. 1 shows an apparatus according to the prior art, which has already been described in detail further above, as a result of which there is no need to describe it in detail at this point.
FIG. 2 shows one exemplary embodiment of the apparatus 9 according to the invention, which is once again intended to supply power to a long stator winding 1 composed of a plurality of winding sections 2 . The apparatus comprises a supply line 6 , which is connected via an additional conductor 10 and an additional conductor switching unit 11 to an energy source which is a converter, which is not illustrated in the figure, wherein the converter is connected via a direct-current circuit or a DC voltage intermediate circuit to a further converter, which itself is connected to an alternating-current electrical power supply system. It is also possible to connect a further supply line 16 to the already mentioned supply line 6 via a range switch 17 , which further supply line 16 likewise supplies a long stator winding 2 and likewise has winding sections which can be correspondingly connected. However, these are not illustrated in the figure, for clarity reasons.
As in the case of the prior art, a section switch 3 and a star-point switch 4 are provided in order to pass current through a winding section 2 . When the section switch 3 and the star-point switch 4 are closed, a current flows from the energy source via the additional line 10 , the closed additional conductor switch unit 11 , the supply line 6 , the closed section switch 3 into the respective winding section 2 , and from there via the star-point switch 4 to the star point 5 which, for example, is grounded.
In order to prevent high losses, only one winding section 2 is generally ever connected to the supply line 6 on one side and to the star point 5 on the other side. The section switch 3 and the star-point switch 4 of the other winding sections through which no current is intended to be passed are in contrast generally open. This also applies to the range switch 17 which may be provided. In order to compensate for the inductive impedance of the winding section 2 through which current is in each case being passed, a control unit 12 is provided, and is connected to the section switches 3 via a respective signal line 13 . Furthermore, the control unit 12 is also connected to the additional conductor switching units 11 and to the range switch 17 via a signal line 13 . For power factor correction, the control unit 12 closes a specific number of section switches 3 and/or additional conductor switching units 11 . In this case, the section switches 3 which are operated are associated with winding sections 2 through which no current is being passed, that is to say whose star-point switch 4 is open, as a result of which its capacitive impedance 7 can be used for power factor correction without this leading to an unintentional current flow through further winding sections 2 . In order to notify the position of the respective star-point switch 4 to the control unit 12 , the control unit 12 is also connected to the star-point switches 4 by a signal line, although this is not illustrated in FIG. 1 , for clarity reasons.
In order to decide how many section switches 3 the control unit 12 should close when the star-point switches 4 are open, for power factor correction, the control unit 12 is connected to measurement sensors which are not illustrated in the figures. In the illustrated exemplary embodiment in FIG. 2 , the measurement sensors detect current and voltage on the supply line 6 . For clarity reasons, the figures show only one phase of the supply line, which has a total of three phases, and in each case only one pole of the respective switch or of the respective switch unit. This applies in a corresponding manner to the long stator winding 1 with the winding sections 2 . However, at this point, it should be noted that the measurement sensors each detect current and voltage on a phase basis, as a result of which the control unit 12 can use the measurement signals obtained to determine the reactive power in the supply line 6 while power is being supplied to the long stator winding 1 . Furthermore, the control unit 12 has adjustment parameters, that is to say for example indications relating to the impedance of a winding section 2 which is not energized but can be connected. Internal control logic in the control unit 12 uses this information to decide which section switches 3 and which additional conductor switching units 11 and range switches 17 are closed for power factor correction. It should be noted that a range switch 17 can be used to include further winding sections 2 of another long stator section 2 of the type described above for power factor correction.
FIG. 3 shows a further exemplary embodiment of the apparatus according to the invention, in which the control unit 12 is connected to a reactance unit 14 . The reactance unit 14 is connected to the winding section 2 via an electrical conductor 15 . By way of example, the reactance unit 14 has a switching unit, which is not illustrated in the figures but can be closed when required by the control unit 12 , as well as a capacitive unit, such as a capacitor connected in star, or the like. The control unit 12 can therefore increase the capacitive impedance of the apparatus by connection of the capacitive unit of the reactance unit 14 , and can therefore compensate for the inductive reactive power requirement.
FIG. 4 shows an exemplary embodiment corresponding to FIG. 3 , but in which the reactance unit 14 is arranged on the star-point side of the winding section 2 , that is to say between the actual winding section 2 and the star-point switch 4 . | A device for supplying energy to a long stator winding having multiple winding sections. The device includes an energy source, a supply line connected to the energy source, section switches that are connected to the supply line and that each have a connection for connecting the switch to one winding section each. The device is configured to enable reactive (idle) power compensation independently of the closed-loop control of the energy source. The device for the reactive power compensation is configured to adjust the impedance of the device. | 8 |
CROSS REFERENCE TO RELATED APPLICATIONS
The present application is based on and claims under 35 U. S. C. § 119 with respect to Japanese Patent Application No. 2002-281495 filed on Sep. 26, 2002, the entire contents of which are incorporated herein by reference.
FIELD OF THE INVENTION
The present invention is generally directed to valve timing control device. More particularly, the present invention pertains to a valve timing control device for controlling an opening and closing time of at least one of an intake valve and an exhaust valve of a internal combustion engine on the basis of the running condition of a vehicle-mounted internal combustion engine.
BACKGROUND OF THE INVENTION
In general, the variable valve timing control device comprising: a drive member rotatable in synchronization with a crankshaft, a rotatable driven member connected to a camshaft arranged co-axially with the drive member, a hydraulic chamber formed at one of the drive member and the driven member, a vane dividing the hydraulic chamber into an advanced angle chamber and a retarded angle chamber, a relative rotation phase controlling mechanism which controls a relative rotation phase between the drive member and the driven member between a most retarded angle phase in which a volume of the advanced angle chamber is a maximum and a most advanced angle phase in which a volume of the retarded angle chamber is a maximum by supplying or discharging operation fluid to and/or from the advanced angle chamber and the retarded angle chamber.
Further, the variable valve timing control device comprising: a lock mechanism which restricts relative rotation between the drive member and the driven member, when the relative rotation phase is a predetermined lock phase between the most advanced angle phase and the most retarded angle phase at the engine start in order to prevent the vane from oscillating in the fluid pressure chamber by periodical fluctuation torque of a cam causing by the camshaft opening and closing the valve and obtain the smooth startability of the engine and the adjusting width extending to both advanced angle direction and the retarded angle direction of the relative rotation phase of the both rotation member
Aforesaid lock mechanism biases a lock body provided on the rotatable drive member to the rotatable driven member side by a spring and insert the aforesaid lock body into the lock oil chamber provided on the rotatable driven member and restrain the aforesaid relative rotation and obtain lock status. On the other hand aforesaid lock mechanism draw back the lock body to the rotatable drive member side by supplying lock oil in the lock oil chamber and providing oil pressure and unlock the aforesaid lock status
A known valve timing control device of the general kind is disclosed in Japanese-Laid-Open 2001-50063, and it detects the relative rotation phase between the rotatable drive member and the rotatable driven member at the engine stop upon input of a signal indicating engine stop from the ignition key switch and feedback-controls the aforesaid relative rotation phase control mechanism and adjust the relative rotation phase of both rotation members to lock phase side and restrains the aforesaid relative rotation and obtain lock status by the aforesaid lock mechanism.
By the way, although the aforesaid control mechanism of the aforesaid valve timing control device needs to drain lock oil from the lock oil chamber and obtain the aforesaid lock status during the relatively short time from input of a signal indicating engine stop from the ignition key switch to rotation stop of the crankshaft. The aforesaid control mechanism of the aforesaid valve timing control device occasionally can not obtain the aforesaid lock status when the engine oil is yet low temperature and of high viscosity while the engine is not warm.
Therefore, A known valve timing control device of the general kind is disclosed in Japanese-Laid-Open 2001-355468, and it passes the relative rotation phase of both rotation member through the lock phase and obtains the lock status by the lock mechanism by making the advanced angle chamber, the retarded angle chamber and the lock oil chamber at drain status when the crankshaft is compulsorily rotated by the starter upon input of a signal indicating engine stop from the ignition key switch (hereinafter called cranking) and oscillating the aforesaid vane in the fluid pressure chamber by the fluctuation torque of the cam in order to obtain the aforesaid lock status at the engine start.
The causes of preventing the aforesaid lock status from being obtained are that the remaining operational oil in the advanced angle chamber or the retarded angle chamber prevents the relatively rotation, in other word, the oscillation in the fluid pressure chamber between the rotatable drive member and the rotatable driven member and that the remaining oil in the lock oil chamber prevents the lock body from inserting into the lock oil chamber.
Especially in case that the engine oil is low temperature as the engine not warm and the engine is restarted immediately after the engine stops, the operational oil in the advanced angle chamber or the retarded angle chamber and the lock oil in the lock oil camber occasionally can not be drained perfectly because the engine oil is yet low temperature and of high viscosity. In case that the lock oil is not drained perfectly from lock oil chamber the aforesaid lock oil prevent the relative rotation of both rotation member and the insert of the lock body and the lock status can not be obtained.
SUMMARY OF THE INVENTION
It is, therefore, an object of the present invention to provide an improved valve timing control device which overcomes the above drawbacks.
It is another object of the present invention to provide an improved valve timing control device which obtains exactly the lock status to restrain the relative rotation between the rotatable drive member and the rotatable driven member.
The invention provides a variable valve timing control device comprising: a drive member rotatable in synchronization with a crankshaft, a rotatable driven member connected to a camshaft arranged co-axially with the drive member, a hydraulic chamber formed at one of the drive member and the driven member, a vane dividing the hydraulic chamber into an advanced angle chamber and a retarded angle chamber, a relative rotation phase controlling mechanism which controls a relative rotation phase between the drive member and the driven member between a most retarded angle phase in which a volume of the advanced angle chamber is a maximum and a most advanced angle phase in which a volume of the retarded angle chamber is a maximum by supplying or discharging operation fluid to and/or from the advanced angle chamber and the retarded angle chamber, a lock mechanism which restricts relative rotation between the drive member and the driven member, when the relative rotation phase is a predetermined lock phase between the most advanced angle phase and the most retarded angle phase, a control mechanism performing an intermediate phase operation upon input of a signal indicating engine stop to position the relative rotation phase intermediate between the most advanced angle phase and the most retarded angle phase by operating the relative rotation phase controlling mechanism, and performing a drain operation to drain the operation fluid from both the advanced angle chamber and the retarded angle chamber after performing the intermediate phase operation.
BRIEF DESCRIPTION OF THE DRAWING FIGURES
FIG. 1 is an axial cross-sectional view showing structure of the valve timing control device.
FIG. 2 is a cross-sectional view showing the lock status of the valve timing control device by the lock mechanism.
FIG. 3 is a cross-sectional view showing the unlock status of the valve timing control device by the lock mechanism.
FIG. 4 is an operation chart showing the operation of the control valve.
FIG. 5 is a timing chart showing some kinds of status at the engine start.
FIG. 6 is a flow chart showing the control status of the valve timing control device at the engine stop.
FIG. 7 is a flow chart showing the maintain operation of the valve timing control device shown in FIG. 6 .
FIG. 8 is a flow chart showing the transfer operation of the valve timing control device shown in FIG. 6 .
FIG. 9 is a timing chart showing some kinds of status when the maintain operation is prosecuted at the normal stop process.
FIG. 10 is a timing chart showing some kinds of status when the transfer operation is prosecuted at the normal stop process.
FIG. 11 is a timing chart showing some kinds of status when the maintain operation and the transfer operation are not prosecuted at the normal stop process.
FIG. 12 is a timing chart showing some kinds of status when the maintain operation is not prosecuted at the abnormal stop process.
FIG. 13 is a timing chart showing some kinds of status when the maintain operation is prosecuted at the abnormal stop process.
DETAILED DESCRIPTION OF THE INVENTION
A valve timing control device in accordance with a preferred embodiment of the present invention will be described with reference to Figures.
A valve timing control device referring to FIG. 1 is provided with an outer rotor 2 which is the drive-rotation member rotated simultaneusly with the crankshaft of the engine for automobile and an inner rotor 1 which is the driven-rotation member rotated simultaneusly with the camshaft 3 .
The inner rotor 1 is assembled integrally on the projecting end of the cam shaft 3 rotatably integrally with the camshaft 3 mounted on a cylinder head of the engine.
The outer rotor 2 is mounted on the outer circumference of the inner rotor 1 so as to be able to rotate within a specified range relative to the inner rotor 1 and includes a front plate 22 and a rear plate 23 and a timing sprocket 20 which is mounted integrally on the outer circumference of the outer rotor 2 .
The rotation transmitting member 24 which is a timing chain or a timing belt etc is installed between the timing sprocket 20 and a gear which is mounted on the crank shaft of the engine.
When the crank shaft begins to be rotated, the rotation torque is transmitted to the timing sprocket 20 via the rotation transmitting member 24 . The outer rotor 2 provided with the timing sprocket 20 is rotated in the rotation direction S shown in FIG. 2 . The inner rotor 1 is rotated in the rotation direction S and the camshaft 3 is rotated. The cams mounted on the camshaft 3 push down and open an intake valve or an exhaust valve.
The outer rotor 2 provided with several projections 4 acting as the shoe projecting in radial direction which are put side-by-side in rotational direction. A fluid pressure chamber 40 which is defined between the inner rotor 1 and the outer rotor 2 is formed between the abutting projections 4 on the outer rotor 2 .
A vane groove 41 are formed on the outer periferal surface of the inner rotor 1 at the position which face to each of the fluid pressure chamber 40 . A vane 5 which divides the fluid pressure chamber 40 into an advanced angle chamber 43 and a retarded angle chamber 42 in relative rotational direction(S 1 , S 2 direction shown in FIG. 2) is inserted into the vane groove 41 in a manner to be slidable in radial direction.
The advanced angle chamber 43 is connected to an advanced angle passage 11 formed on the inner rotor 1 . The retarded angle chamber 42 is connected to a retarded angle passage 10 formed on the inner rotor 1 . The advanced angle passage 11 and the retarded angle passage 10 are connected to an after-mentioned hydraulic pressure circuit 7 .
The hydraulic pressure circuit 7 functions as relative rotational phase control device which supplies and discharges engine oil as operation oil to/from one of or both the advanced angle chamber 43 or/and the retarded angle chamber 42 via the retarded angle passage 10 and the advanced angle passage 11 . The hydraulic pressure circuit 7 changes the relative position of the vane 5 in the fluid pressure chamber 40 and control the relative rotational phase of the inner rotor 1 and the outer rotor 2 (hereinafter called as the relative rotational phase of both rotors) between the most advanced angle phase(the relative rotational phase of both rotors is at which the volume of the advanced angle chamber 43 is maximum) and among the most retarded angle phase(the relative rotational phase of both rotors is at which the volume of the retarded angle chamber 42 is maximum).
For more detail, the hydraulic pressure circuit 7 comprises a pump 70 and a control valve 76 and an oil pan 76 . The pump 70 is driven by driving force of the engine and supply the engine oil which is operational oil or after-mentioned lock oil to the control valve 76 . The control valve 76 supplies and drains engine oil to/from several ports by changing the position of the spool with controlling a mount of the electricity of the ECU 9 . The oil pan 75 stores engine oil. The aforesaid advanced angle passage 11 and retarded angle passage 10 are connected to specified port of the aforesaid control valve 76 .
A lock mechanism 6 which locks the relative rotational phase of both rotors when the relative rotational phase of both rotors is the predetermined lock phase between the most advanced angle phase and the most retarded angle phase is provided between the inner rotor 1 and the outer rotor 2 .
The lock mechanism 6 comprises a retarded lock portion 6 A and an advanced lock portion 6 B and a lock oil chamber 62 which is formed as concave at one of the portion on the periferal surface of the inner rotor 1 .
The retarded lock portion 6 A and the advanced lock portion 6 B have the lock body 60 which is provided on the outer rotor 2 in a manner to be slidable in radial direction and a spring 61 which biases the lock body 60 in radial direction. The shape of the lock body 60 can be plate-shape or pin-shape or other shape.
The aforesaid retarded lock portion 6 A prevents the relative rotation of the inner rotor 1 from rotating to the retarded angle direction from the lock phase relative to the outer rotor 2 when the lock body 60 is inserted into the lock oil chamber 62 . The aforesaid advanced lock portion 6 B prevents the relative rotation of the inner rotor 1 from rotating to the advanced angle direction from the lock phase when the lock body 60 is inserted into the lock oil chamber 62 . So-called lock status that the relative rotational phase of both rotors can be locked at the predetermined lock phase set between the most advanced angle phase and the most retarded angle phase by inserting both lock body 60 of the retarded lock portion 6 A and advanced lock portion 6 B into the lock oil chamber 62 is obtained. The aforesaid lock phase is set at the phase where the opening and closing timing of the valve of the engine causes the smooth starting of the engine.
The aforesaid lock oil chamber 62 is communicated to a lock oil passage 63 formed in the inner rotor 1 . The lock oil passage 63 is connected to the specified port on the control valve 76 of the aforesaid oil pressure circuit 7 . In other word, the hydraulic pressure circuit 7 supplies and discharges engine oil as lock oil via the lock oil passage 63 to and from the lock oil chamber 62 . The lock body 60 slide back and unlock the lock condition of the relative rotational phase of both rotors as shown in FIG. 3 when the lock oil is supplied to the lock oil chamber 62 from the control valve 76 .
As shown in FIG. 4 the control valve 76 of the oil pressure circuit 7 changes the position of the spool from a position W 1 to a position W 4 in proportion to the mount of the electricity from the ECU 9 and supplies and drains and stops the engine oil as lock oil to and from the advanced angle chamber 43 or/and the retarded angle chamber or/and the lock oil chamber 62 .
In other word, when the spool position of the control valve 76 is set at the position W 1 , the drain operation to drain operation oil in both the advanced angle chamber 43 and retarded angle chamber 42 and lock oil in the lock oil chamber 62 to the oil pan 75 can be prosecuted.
When the spool position of the control valve 76 is set at the position W 2 , the advanced angle transfer operation to supply operation oil in the lock oil chamber 62 and unlock the lock condition of the relative rotational phase of both rotors 1 , 2 and drain operation oil from the retarded angle chamber 42 and supply operational oil to advanced angle chamber 43 and transfer the relative rotational phase of both rotors 1 , 2 into the advanced angle direction S 2 can be prosecuted.
When the spool position of the control valve 76 is set at the position W 3 , the hold operation to unlock the lock condition of the relative rotational phase of both rotors 1 , 2 and stop supplying operation oil to the advanced angle chamber 43 and the retarded angle chamber 42 and hold the relative rotational phase of both rotors 1 , 2 at specified phase.
When the spool position of the control valve 76 is set at a position W 4 , the retarded angle transfer operation to unlock the lock status of the relative rotational phase of both rotors 1 , 2 and drain operation oil from the advanced angle chamber 43 and supply operation oil to the retarded angle chamber 42 and transfer the relative rotational phase of both rotors 1 , 2 to the retarded angle direction S 1 can be prosecuted. By the way, the way of the transfer process of the control valve 76 is not defined as aforesaid way and it can be changed timely.
The ECU 9 provided for the engine incorporates a memory storing the specified program and CPU and input-output-interface and etc and acts as the control mechanism of the valve timing control device of this invention.
A detecting signal of a cam angle sensor 90 a detecting the camshaft phase, a crank angle sensor 90 b detecting the crankshaft phase, an oil temperature sensor 90 c detecting the engine oil temperature, a rotation sensor 90 d detecting the crankshaft rotation number(the engine rotation number), an ignition key switch (abbreviated to IG/SW), a vehicle speed sensor, a cooling water temperature sensor of engine, a throttle opening sensor and other sensors is inputted to the ECU 9 . The ECU 9 can obtain the relative rotational phase of both rotors 1 , 2 of the valve timing control device from the camshaft phase detected by the cam angle sensor 90 a and the crankshaft phase detected by the crank angle sensor 90 b.
The ECU 9 regulates the mount of the electricity to the control valve 76 of the aforesaid oil circuit 7 ECU on the basis of the aforesaid engine oil temperature, the crankshaft rotation number, the vehicle speed, the throttle opening travel and the other engine performance parameter and controls the relative rotational phase of both rotors 1 , 2 at the phase which is suitable for the performance parameter.
Next, the control status of the valve timing control device at the engine start is explained on the basis of the FIG. 5 .
The ECU 9 as the control mechanism crank the crankshaft and start the engine after the engine start signal is inputted to the ECU 9 from the IG/SW 90 e . The ECU 9 transfers the spool of the control valve 7 to the position W 1 and drain operation oil in the advanced angle chamber 43 , the retarded angle chamber 42 and the lock oil chamber 62 when the engine starts.
Further, the vane 5 reciprocates in the fluid pressure chamber 40 by the periodical cam fluctuation torque caused by the camshaft opening and closing the valve when the crankshaft is cranked at the condition while the operation oil in both the advanced angle chamber 43 and the retarded angle chamber 42 is drained. The relative rotational phase of both rotors 1 , 2 fluctuates periodically among the specified phase including the aforesaid lock phase. A pair of lock bodies 60 are biased by the spring 61 to the inner rotor 1 side when the engine starts.
In other word, the movement that the relative rotational phase of both rotors 1 , 2 fluctuates periodically among the specified phase including the aforesaid lock phase while a pair of lock bodies 60 are biased by the spring 61 to the inner rotor 1 side makes a pair of lock bodies 60 plunge into the lock oil chamber 62 at the moment when the relative rotational phase of both rotors 1 , 2 is the lock phase and makes the relative rotational phase of both rotors 1 , 2 be hold at lock phase fairly and be locked when the temperature of the lock oil is relatively high and the pressure of the lock oil in the lock oil chamber 62 is almost zero.
Therefore, if the aforesaid relative rotational phase of both rotors 1 , 2 is transferred to the lock phase immediately when the engine starts the good startability of the engine can be obtained
Next, the control status of the valve timing control device at the engine stop is explained on the basis of the FIGS. 6 to 13 .
The ECU 9 as the control mechanism determines if the engine stop signal is inputted from the IG/SW 90 e (step 100 ) as shown in FIG. 6 . When the ECU 9 determines that the engine stop signal is inputted the after-mentioned normal stop processes of step 101 to 104 are prosecuted in accordance with the engine normal stop. When the ECU 9 determines that the engine stop signal is not inputted the after-mentioned abnormal stop processes of step 105 to 108 are prosecuted in accordance with the engine abnormal stop on the basis of the happening of the engine stall etc. After the prosecution of the aforesaid normal stop processes or abnormal stop processes the ECU 9 transfers the spool of the control valve 7 to the position W 1 and prosecutes the drain operation to drain operation oil in both the advanced angle chamber 43 , the retarded angle chamber 42 and the lock oil in the lock oil chamber 62 at the step 109 .
Firstly the mode in which the drain operation is prosecuted at the aforesaid step 109 after the normal stop processes is explained. After the ECU 9 determines that the engine stop signal is inputted from the IG/SW 90 e at the aforesaid step 100 the ECU 9 firstly prosecutes the step 101 and determines if the engine oil temperature detected by the oil temperature sensor 90 c reaches to the predetermined warming-up temperature and whether the engine is at warming-up condition or not.
Next, when the ECU 9 determines that the engine is not at warming-up condition at the step 101 the ECU 9 prosecutes the step 102 and prosecutes the after-mentioned specified holding operation. When the ECU 9 determines that the engine is at warming-up condition at the step 101 the ECU 9 prosecutes the step 103 .
When the ECU 9 determines that the engine is not at warming-up condition at the aforesaid step 101 it is considered that the relative rotational phase of both rotors 1 , 2 is hold at the lock phase by the lock mechanism 6 with the spool position of the control valve 76 set to the position W 1 or that the relative rotational phase of both rotors 1 , 2 is hold near the lock phase which is at the middle phase between the aforesaid most advanced angle phase and the most retarded angle phase with the spool position of the control valve 76 set to the position W 3 .
Therefore, when the ECU 9 determines that the engine is not at warming-up condition at the step 101 the ECU 9 maintains the mount of the electricity to the control valve 76 of the electricity at the engine stop signal input until the rotational number of the engine becomes zero as shown in FIG. 7 . The ECU 9 prosecutes the hold operation to hold the relative rotational phase of both rotors 1 , 2 at the middle phase which is at the engine stop signal input. After the hold operation at the step 102 the ECU 9 prosecutes the drain operation of the aforesaid step 109 .
In other word, when the ECU 9 determines that the engine is not at warming-up condition at the step 101 the ECU 9 hold the relative rotational phase of both rotors 1 , 2 and prosecutes the drain operation at the aforesaid step 102 of the hold operation as shown in FIG. 9 until the rotation of the crankshaft stops at the hold operation of the aforesaid step 102 . If the operation oil in the advanced angle chamber 43 or the retarded angle chamber 42 or the lock oil chamber 62 is not drained because of high viscosity at low temperature and the relative rotational phase of both rotors 1 , 2 can not be oscillated with enough width the relative rotational phase of both rotors 1 , 2 is oscillated at near the middle phase and can be passed exactly through the lock phase and is secured of the lock status by the lock mechanism 6 .
When the ECU 9 determines that the engine is at warming-up condition at the aforesaid step 101 the ECU 9 prosecutes the step 103 and detects the relative rotational phase of both rotors 1 , 2 by the camshaft phase detected by the cam angle sensor 90 a and the crankshaft phase detected by the crank angle sensor 90 b and determines whether the relative rotational phase of both rotors 1 , 2 is the middle phase.
When the ECU 9 determines that the relative rotational phase of both rotors 1 , 2 is the most retarded angle phase or the most advanced angle phase which is not the middle phase the ECU 9 prosecutes the transfer operation at the after-mentioned step 104 . When the ECU 9 determines that the relative rotational phase of both rotors 1 , 2 is the middle phase the drain operation of the aforesaid step 109 is prosecuted.
The transfer operation of the aforesaid step 104 as shown in FIG. 8 for transferring the relative rotational phase of both rotors 1 , 2 to the middle phase firstly calculates the mount of the electricity for the control valve 76 and the electricity time to maintain the mount of the electricity as a control parameter of control valve 76 on the basis of the engine oil temperature detected by the oil temperature sensor 90 c , the crankshaft rotation number detected by the rotation sensor 90 d , the relative rotational phase of both rotors 1 , 2 detected by the cam angle sensor 90 a and the crank angle sensor 90 b , the temperature of the cooling water, the shift range of the automatic transmission and the engine operation parameter at the moment when the engine stop signal is inputted. Then the control valve 76 is controlled on the basis of the aforesaid calculated control parameter. The advanced angle moving operation or the retarded angle moving operation is prosecuted to set the position of the spool of the control valve 76 at the position W 2 or the position W 4 .
In other word, the mount of the electricity for the control valve 76 and the electricity time to maintain the mount of the electricity to set the position of the spool of the control valve 76 at the position W 2 or the position W 4 in order to obtain the target adjusting volume of the relative rotational phase of both rotors 1 , 2 by realizing the target adjusting volume for moving the relative rotational phase of both rotors 1 , 2 to the middle phase at the engine stop is calculated at the step 104 of the transfer operation.
The relative rotational phase of both rotors 1 , 2 is transferred to the middle phase by turning on electricity for the control valve 76 in accordance with the calculated the mount of the electricity and the electricity time and prosecuting the advanced angle transfer operation or the retarded angle transfer operation by the control valve 76 during the specified electricity time even where the relative rotational phase of both rotors 1 , 2 is the most retarded angle phase or the most advanced angle phase at the moment when the engine stop signal is inputted. Then the aforesaid drain operation at the step 109 is prosecuted and relatively hot operation oil and lock oil is drained immediately and the aforesaid relative rotational phase of both rotors 1 , 2 oscillates at the middle phase and the operation oil in both the advanced angle chamber and the retarded angle chamber is drained and the engine stops.
Thus when the engine is determined to be at warming-up status at the step 101 and the relative rotational phase of both rotors 1 , 2 is determined not to be the middle phase the drain operation at the step 109 is prosecuted after the relative rotational phase of both rotors 1 , 2 is set at the middle phase as shown in FIG. 10 . Because the operation oil in the advanced angle chamber 43 or the retarded angle chamber 42 or the lock oil in the lock oil chamber 62 is relatively high temperature and of low viscosity after the drain operation at engine stop or after cranking start of the crankshaft at the engine restart the relative rotational phase of both rotors 1 , 2 can be oscillated at the middle phase excellently and can be secured to be at the lock status by the lock mechanism 6 with passing through the lock phase exactly.
Meanwhile when the relative rotational phase of both rotors 1 , 2 is determined to be the middle phase the ECU 9 oscillates excellently and can secure the aforesaid relative rotational phase of both rotors 1 , 2 at the lock status by the lock mechanism 6 after the drain operation at engine stop or after cranking start of the crankshaft at the engine restart by prosecuting the drain operation of the aforesaid step 109 immediately as shown in FIG. 11 because the operation oil in the advanced angle chamber 43 or the retarded angle chamber 42 or the lock oil in the lock oil chamber 62 is relatively high temperature and of low viscosity.
Secondly, the mode in which the drain operation of the aforesaid step 109 is explained after the prosecution of the abnormal stop operation.
On the abnormal stop operation after the engine stop signal is determined not to be inputted from IG/SW 90 e at aforesaid step 100 the ECU 9 prosecutes firstly the step 105 and determines if the engine tall is avoided by the inputting avoidance signal of the engine stall. In case the engine tall can be avoided the normal operation control is prosecuted and the engine running is maintained.
Meanwhile in case the engine stall is determined not to be avoided the step 106 is prosecuted it is determined if the relative rotational phase of both rotors 1 , 2 is near the lock phase as same as the aforesaid step 103 . On the other hand, the step 107 is prosecuted and it is determined whether the engine at the warming-up status or not as same as the aforesaid step 101 .
Meanwhile in case that the relative rotational phase of both rotors 1 , 2 is determined not to be the middle phase at aforesaid step 106 or in case that the engine is at the warming-up status but the relative rotational phase of both rotors 1 , 2 is determined to be at the middle phase at aforesaid step 106 the drain operation 108 of the aforesaid step 109 immediately.
Thus in case that the relative rotational phase of both rotors 1 , 2 is not at the middle phase or the engine is at the warming-up status the relative rotational phase of both rotors 1 , 2 can be oscillated efficiently and the operation oil in both the advanced angle chamber 43 and the retarded angle chamber 42 is drained excellently by prosecuting immediately the drain operation when the rotation of the crankshaft immediately after the engine stall and the engine can be stopped Therefore the relative rotational phase of both rotors 1 , 2 is oscillated efficiently and the lock status is secured by the lock mechanism 6 after the drain operation at the engine stop or after the cranking start of the crankshaft at the engine restart.
On the other hand in case that the relative rotational phase of both rotors 1 , 2 is determined to be the middle phase at the aforesaid step 106 and the engine is not at the warming-up status at the aforesaid step 106 the mount of the electricity for the control valve 76 is maintained to the mount of the electricity of the time and the hold operation to hold the relative rotational phase of both rotors 1 , 2 at the middle phase is prosecuted and the drain operation of the aforesaid step 109 is prosecuted after the hold operation of the aforesaid step 108 .
In other word, when the ECU 9 determines that the engine is not at warming-up condition at the step 107 the ECU 9 hold the relative rotational phase of both rotors 1 , 2 and prosecutes the drain operation at the aforesaid step 109 of the hold operation as shown in FIG. 13 until the rotation of the crankshaft stops at the hold operation of the aforesaid step 108 . If the operation oil in the advanced angle chamber 43 or the retarded angle chamber 42 or the lock oil chamber 62 is not drained because of high viscosity at low temperature and the relative rotational phase of both rotors 1 , 2 can not be oscillated with enough width the relative rotational phase of both rotors 1 , 2 is oscillated near middle phase and can be passed exactly through the lock phase and is secured of the lock status by the lock mechanism 6 .
Although in this embodiment of the invention the control valve consists of single valve, it is permitted that the control valve consists of plural hydraulic control valve not only apply to the single valve. For example, it is permitted that the control valve comprises the control valve which supply/drain the operation oil to/from the retarded angle chamber 42 and the control valve which supply/drain the operation oil to/from the advanced angle chamber 43 and the control valve which supply/drain the operation oil to/from the lock oil chamber 62 .
Although in the aforesaid embodiment of the invention whether the engine is at the warming-up status or not is determined by determining whether the engine oil temperature reaches the predetermined temperature. It is permitted that whether the engine is at the warming-up status or not is determined by determining whether the engine cooling-water temperature reaches the predetermined temperature as other way.
It is permitted that the various components of the valve timing control device afore-explained can be replaced with the unitary body combined the vane 5 and the inner rotor 1 or another component of the lock mechanism 6 and etc unless the embodiment is out of the subject-matter of the invention | A variable valve timing control device includes a drive member rotatable in synchronization with a crankshaft, a rotatable driven member connected to a camshaft arranged co-axially with the drive member, a hydraulic chamber formed at one of the drive member and the driven member, a vane dividing the hydraulic chamber into an advanced angle chamber and a retarded angle chamber, a relative rotation phase controlling mechanism which controls a relative rotation phase between the drive member and the driven member between a most retarded angle phase in which a volume of the advanced angle chamber is a maximum and a most advanced angle phase in which a volume of the retarded angle chamber is a maximum by supplying or discharging operation fluid to and/or from the advanced angle chamber and the retarded angle chamber, a lock mechanism which restricts relative rotation between the drive member and the driven member, when the relative rotation phase is a predetermined lock phase between the most advanced angle phase and the most retarded angle phase, a control mechanism performing an intermediate phase operation upon input of a signal indicating engine stop to position the relative rotation phase intermediate between the most advanced angle phase and the most retarded angle phase by operating the relative rotation phase controlling mechanism, and performing a drain operation to drain the operation fluid from both the advanced angle chamber and the retarded angle chamber after performing the intermediate phase operation. | 5 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a new device of the machine system commonly named “DRY CLEANING MACHINE” used to clean clothes, fabrics or metal objects by means of a solvent other than water and therefore subject to the risk of explosion or fire due to the flammability of the solvent.
2. Description of Related Art
The present invention is an improvement of the invention already described in a previous Italian patent application no. BO 99 A 000333 by the same applicant.
BRIEF SUMMARY OF THE INVENTION
The present invention described herewith, designed for a traditional dry cleaning machine, entails the elimination of the oxygen in the atmosphere within the machine at the beginning of each cleaning cycle by means of the controlled combustion on a catalytic bed. The combustible used is the same solvent used to clean, kept as vapour in a flow of air. The main improvement currently added consists of the crucial addition of one or a number of sensors, namely probes that are sensitive to the concentration of oxygen, the signals of which are utilized to control the oxygen elimination process until stopping it when the desired concentration is reached.
This and other characteristics will further relate to a simple form of the invention given as indicated, which is not binding, on the scope of this patent.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
Referring to the enclosed drawings:
FIG. 1 shows the present operation as a diagrammatic illustration with the addition of the new modifications compared to that of the prior art
FIG. 2 is a diagrammatic illustration of the system of the prior art Italian patent (BO 99, A 000333).
DETAILED DESCRIPTION OF THE INVENTION
The space 1 is inside the machine containing both air and a certain amount of solvent 2 in the liquid state. As is known, the air is taken in by a fan 3 and sent in contact with an exchanger or cooling coil 5 , cooled by a refrigeration circuit, in order to condensate the water and solvent vapours together with the other volatile substances within the air. The condensation collects in collector 4 then the air heats in contact with a second heating coil 6 that is warmed by means of an appropriate connection to the hot side of the refrigeration circuit. The air thus heated returns finally to the space 1 through passage 7 .
As already illustrated in the previous patent application, some of the air pushed by the fan 3 is deflected into passage 10 and by means of the container 12 and the exchanger 15 , it reaches the burner 16 that contains the heating element 17 and the catalytic mass 18 . The air is outlet from the burner hotter but depleted of oxygen due to the effect of the combustion process. It cools in the exchanger 15 and again in the water refrigerator 19 before it returns to the space 1 through passage 20 .
The modifications added to this invention compared to the prior are configuration include first and foremost the addition of at least one oxygen concentration sensor. In the diagram of enclosed FIG. 1, two probes are illustrated with numbers 21 and 22 respectively.
The consequent modifications are listed throughout the description. The air to be conveyed to the burner is deflected into passage 10 immediately downstream from the fan 3 without crossing the coils 5 and 6 , cold and hot respectively. It has been noticed that, thanks to the control achieved by the oxygen sensors, the slight temperature variations to which the air drawn and pushed by the fan 3 may be controlled and the consequent difference in the solvent vapour concentration within it can now be tolerated. Consequently the function of the carburetor previously assigned to the tank 12 is outdated and therefore it is no longer necessary to flow into this some liquid solvent by means of a pump. The tank 12 is however still useful as a separator of any drops of liquid pulled in by the air. The solvent thus held back is then returned to space 1 through passage 14 . Finally it is now preferred that passage 20 through which the burnt air runs, leads out directly in space 1 rather than immediately downstream from fan 3 as was previously. This enables an improved re-mixing of the air in space 1 , an increase in oxygen concentrations and solvent vapours in the flow pushed by the fan.
The oxygen probes 21 , 22 used are preferably those known as “Lambda probes” which are often used with catalytic purifiers of the gas outlet from explosion motors. Their operation principle is based on the production of an electromotive force (e.m.f) of electro-chemical nature and precisely the type called e.m.f. of concentration on the two faces of a solid electrolytic pad based on zirconium oxide, respectively exposed to the atmospheric oxygen and the more diluted oxygen in the area to be controlled. The e.m.f collected by means of electrodes is then driven by wires outside the sensor element to be processed with known methods and instruments.
As already mentioned, the most important task assigned to the oxygen sensors is to indicate that a pre-set concentration has been reached and that therefore the elimination process can be stopped. This brings about two advantages: the consumption of solvent is reduced to the smallest amount necessary and the undesired formation of carbon dioxide is avoided. Even if one Lambda probe is sufficient to control the process and considering the reasonable cost of these components, it has been preferred to use more than one for additional safety.
In the example illustrated in FIG. 1, there are two probes. Probe 21 is used to stop the process and, is fitted inside the burner 16 in order to obtain as prompt a reaction as possible. When this indicates that the pre-set concentration has been reached (not necessarily zero) valve 11 closes and shuts off the flow of air to the burner. If there is a failure in the seal, the oxygen concentration may rise again and these abnormal conditions can be detected by probe 22 fitted for this purpose in space 1 . Together with providing an alarm signal, the e.m.f sent from probe 22 can trigger the re-opening of the valve 11 together with a new elimination cycle or it can trigger the final stoppage of the machine.
Amongst the various forms of execution of the invention which is substantially identical to that described, even if the parts are different, it may sometimes be preferable to use a separate fan from the main one, operating in parallel with this to send the air from space 1 to the burner 16 . In this case valve 11 may be missing and the flow of air to the burner is stopped simply by stopping the fan connected to it. Practically speaking, the execution parts, the sizes, the materials, the shape and other details of the invention may in any event vary without exceeding the domain of this industrial patent right. The invention thus conceived is indeed open to many modifications and variations, all within the sphere of the invention concept. Furthermore, all the components may be replaced with others that are technically equivalent. | A process and system for eliminating oxygen in the internal atmosphere of dry cleaning machines by catalytically burning it with the solvent vapors including the process and the relative circuit, which makes the atmosphere within the dry cleaning machine inert, controlling the process by measuring the oxygen in the gaseous mass, obtained using one or a number of Lambda probes. | 3 |
[0001] This invention relates to a method and apparatus for trimming sheet material, typically handled in the form of large coils. More particularly, it relates to the method and apparatus for trimming light gauge aluminum in which the trim or strap is directed positively and effectively into a scrap reclamation system.
BACKGROUND
[0002] Light gauge aluminum coils typically undergo a process of “trimming” or “center cutting”. As the web is uncoiled, it passes over a knife roll. The roll is used in conjunction with stationary knives to cut thin strips of aluminum from the main sheet. Thus, this operation creates continuous strips of aluminum scrap or trim as the coil is processed. These trim strips are generally between ⅛ and 2 inches wide and can be generated at speeds of up to a few thousand feet/minute. This trim is picked up at the machine by use of “trim tubes”. As the trim is cut from the web, a vacuum generated by large fans that are part of the overall “trim system” draws it into the trim tube. The trim is carried by the trim system to a central scrap staging area where it awaits further processing.
[0003] As the processing speed is increased, or if the trim is especially wide, there is a tendency for the trim to be drawn to the surface of the knife roll. Frequently, at some point during processing of a coil, the trim makes contact with and adheres to the knife roll. When this happens, the trim no longer travels into the trim tube but instead, wraps around the roll, quickly causing a web break, shutdown and sometimes further problems.
[0004] Various mechanical devices, such as plate type guides constructed of thin material such as plastic or sheet metal, have been used to try and deflect the trim strip from the roll and guide it into the trim tube. These have largely been unsuccessful due to the difficulty in getting them positioned properly and because the trim strip tends to drag and catch on the surface of the plate. One or more attempts have also been made to guide the trim or scrap into the trim tube with a jet of air blowing toward the mouth of the trim tube, i.e., in the direction of movement of the scrap strip. This method may be effective for thicker and stiffer strip, which has a tendency to escape the vacuum of the trim system and be ejected outward towards the rewind side of the trim tube. But it is of absolutely no use in preventing light gauge trim (less than 0.001″) from being drawn to the surface of the knife roll.
[0005] U.S. Pat. No. 4,484,500 to Reba et al. discloses apparatus to form a spirally wound paper roll product formed from convolutions cut from a parent web. The system includes first and second slitters and trim removal means, positioned close to the second slitter, with Coanda nozzles that induce a fluid flow into a scrap collection unit. The patent indicates that this flow is a combination of the air flow from the nozzles themselves and ambient air entrained therein. The air from the nozzle and entrained ambient air apply a pulling force to both the trim strip and the parent web. The combined flow draws the trim into a trim or scrap collector (column 5, lines 9-18, lines 33-36). In a conventional fan based trim system, this entire function is replaced by fans themselves.
[0006] In the system proposed by Reba et al, the Coanda nozzles must be positioned very close to the moving web and trim strip. As is evident from the drawings, the web used in conjunction with the Reba nozzle must be positioned between the knife roll and the nozzle. This is opposite of several conventional applications. These two requirements make the nozzle very difficult, if not impossible, to use with the configuration of many existing machines. There is nothing in the patent which suggests that a comparable system, or any other system employing one or more air jets, would be suitable for trimming sheet aluminum or other metals. The rollers ( 150 and 152 ) which are critical to the Reba system are highly undesirable for aluminum trimming. The rollers change the path of the strip and would most likely cause several other problems including marking of the strip, strip wrinkles and strip breaks due to the localized force on the strip at the rollers.
SUMMARY OF THE INVENTION
[0007] This invention provides a simple and effective method and apparatus for controlling the movement of a strip of metallic trim into a scrap reclamation system. It utilizes an air nozzle that does not resemble Reba's, either structurally or in method of operation. The orifice of Reba's nozzle is a thin slit—(Coanda nozzles typically have slits on the order of 0.002″ wide). It produces a high velocity stream of turbulent air which tends to conform to a surface downstream of the nozzle, as long as that surface has no sharp corners or other such discontinuities. In the Reba nozzle the Coanda effect causes the air to flow around the curved edge of the nozzle into the scrap tube. As mentioned above, the air from the Coanda nozzle induces ambient air to flow in the same direction, i.e., into the scrap tube. This tends to create a slightly reduced air pressure between the knife roll and the trim strip, in the area where the trim strip leaves the roll.
[0008] The air nozzles of this invention operate in a different manner. Instead of causing a thin high velocity jet of turbulent air to wrap around the end of the nozzle, one or more nozzles direct a stream of air between the knife roll and the trim strip in the area where the trim strip leaves the knife roll. Some embodiments of this invention do take advantage of the same “wall attachment” effect relied on by Reba et al to guide the air around the knife roll to the area where the trim strip separates from the roll. However, instead of causing an air stream to wrap around the end of the nozzle and flow in the scrap tube, as in Reba's system, the nozzle of this invention directs an air stream against the surface of the knife roll and in a direction opposite to the travel of the knife roll and trim strip. The stream of air follows the contour of the roll and provides a wedge between the strip and the roll. This positively forces the trim strip away from the knife roll, rather than relying on whatever tension may be induced in the strip in systems such as Reba's. The nozzles of this invention can be a relatively large distance from the web. The position of the nozzle is not overly critical. Nozzle placement is on the same side of the strip as the knife roll.
[0009] As noted above, Reba's Coanda nozzles must be positioned very close to the moving web and trim strip, between the knife roll and the nozzle. This is opposite to several conventional applications, and make this nozzle very difficult, if not impossible, to use with many existing machines. The systems of this invention avoid this problem. Moreover, they do not require the rollers which are critical to the Reba system. These would be highly undesirable for aluminum trimming because they would change the path of the strip and would most likely cause several other problems, including marking of the strip, strip wrinkles and strip breaks.
[0010] Other features and advantages of this system will be apparent from the following detailed description.
DRAWINGS
[0011] FIG. 1 in a schematic side elevation view illustrating the movement of sheet metal through a slitter embodying this invention.
[0012] FIG. 2 is an enlarged evaluation view, from the same viewpoint on FIG. 1 , illustrating the movement of the fixed web into a slitting station, and the movement of product webs and trim strips from the station.
[0013] FIG. 3 is an end elevation view of a product web and a trim strip leaving the trimming station.
[0014] FIG. 4 is a detailed elevation view taken along lines 4 - 4 in FIG. 2 , of the trim tube and air knife nozzle.
[0015] FIG. 5 is a top plan view of the trim tube and air knife nozzle.
[0016] FIG. 6 is an enlarged side view of the tip of the nozzle shown in FIGS. 2, 4 and 5 .
[0017] FIG. 7 is an end view of the tip shown in FIG. 6 , showing the orifice in the nozzle.
DETAILED DESCRIPTION
[0018] FIG. 1 is a partial side elevation view of a slitter, generally referred to as 10 , embodying this invention. A thin, doubled web 12 of aluminum, comprising two individual or separate sheets 11 , 13 , is fed to slitter 10 from a supply coil 16 on a stand 18 . The doubled web 12 is typically about 0.0005 inches to about 0.002 inches thick and about 24 to 52 inches wide. The individual sheets 11 , 13 that make up the doubled web are typically between about 0.00025 and about 0.001 inches thick. The incoming web passes around idler rollers 23 , 25 , 27 to a slitting station. In the slitting station the web passes over and around knife roll 31 . Two or more slitters 33 (fixed razor blades are illustrated, but rotary blades could also be used) are biased against the web as it passes around the knife roll and make the desired cuts in the web.
[0019] The knife roll 31 , as is typical of rolls used in the slitting of light metal sheets or webs, has a series of alternating square grooves and lands, each approximately 1/32″ wide. The lands support the web, and each slitter blade projects part way into one of the grooves, which helps the blade cut the web cleanly.
[0020] FIGS. 2 and 3 illustrate one of a pair of slitters in the illustrated system: the slitter on the near end ( FIG. 2 ) or right hand end ( FIG. 3 ) of knife roll 31 . A complimentary slitter (not shown) is positioned at the other and of roll 31 . Each removes a trim strip from one edge of the web. The trim strips are typically about ⅛ inch to about 2½ inches wide; depending on the desired final width and cracks or other defects at the edge of the web. If narrower product sheets are desired, an additional pair of slitters may be positioned in the center of knife roll 31 . The center slitters are typically positioned about ⅛ inch to about 1 inch apart, generating a trim strip of the same width.
[0021] In the illustrated slitter the feed web 12 is slit in into two product webs 35 , 37 , which correspond respectively to the upper sheet 11 and lower sheet 13 of doubled web 12 , and two doubled trim strips. The doubled trim strip 39 from the near or right end of web 12 is shown in FIGS. 2 and 3 . Product web 35 is wound on upper rewind coil 41 , and product web 37 is wound on lower rewind coil 43 , using conventional rewind systems. Upper rewind coil 41 and lower rewind coil 43 pull the product webs 35 , 37 and feed web 12 through the slitter 10 , typically at speeds of about 1,000 to about 2,500 feet per minute.
[0022] The trim strip 39 is collected by a trim tube 45 (utilizing vacuum generated by remote fans, not shown) and carried by the remote fans to a central scrap staging area for further processing. The trim strip from the other end of knife roll 31 and any trim strip or strips that may be trimmed from the center of the web are collected by similar trim tubes (not shown) and also carried to the central scrap staging area. A vacuum generated within the tube by large fans (not shown) helps to draw the trim strip 39 into the trim tube 45 . Alternatively or additionally, nozzles may inject air into the trim tube 45 , near its mouth, and induce a flow of entrained air into the trim tube. The drawing or pulling force of the ambient air entrained by the remote fan system, by inductive nozzles, or a combination of one or more fans and nozzles is frequently insufficient to prevent the trim strip from being pulled to the surface of the knife roll. The design of the Reba nozzle has this same deficiency.
[0023] In the illustrated system, however, an air knife nozzle 50 mounted at the upper edge of trim tube 45 , between the trim strip 39 and knife roll, directs a stream of air against knife roll a short distance from the area where the trim strip 39 leaves the knife roll 31 . The nozzle emits a stream of fluid that flows generally outward from the nozzle, with minimal Coanda effects around the side of the nozzle, flows around the side of the knife roll (where it is subject to wall attachment or Coanda effects) and presses against the lower side of the strip, i.e. the side adjacent to the knife roll, in the area where the trim strip separates from the roll The stream generates a positive pressure against the trim strip 39 , which positively forces the trim strip away from the knife roll.
[0024] The illustrated nozzle 50 may be constructed simply by flattening the end of a copper tube to produce the illustrated narrow, elongated orifice 52 . The illustrated nozzle terminates in an end or discharge face 54 that is substantially perpendicular to the bore of the nozzle. The relatively sharp edge or discontinuity between discharge face 54 and the bore of the nozzle reduces any Coanda effects around the side of the nozzle.
[0025] The size and shape of the orifice, and the orientation of the nozzle may be adjusted to suit differing materials, sheet, equipment and/or processes. Various other nozzles, commercial or otherwise, that will provide a positive stream of air against the trim strip in the area where it leaves the knife roller may also be used. In some instances the nozzle may be angled so that the stream of air is aimed directly into the area where the trim strip leaves the roll, but superior performance is generally obtained by directing the air stream against the knife roll, as illustrated, which tends to smooth our turbulence and other discontinuities in the air stream.
[0026] Air is supplied to nozzle 50 through a tube 54 , and the flow rate is adjusted by a flow regulating needle valve (not shown) mounted with other controls for the slitter. The flow may be adjusted manually to the rate which provides the most satisfactory operation. In typical installations, nozzle pressures of 15 to 20 psi and flow rates of 30 to 90 SCFH have been satisfactory. These conditions generate an air stream that provides a positive force against trim strip 39 , which helps to insure that the trim strip will not remain attached to the knife roll and disrupt the slitting operation.
[0027] As may be seen from the foregoing description, this invention provides a system for positively, effectively and economically separating trim scrap from the surface of the knife roll of a slitter. The nozzles of this invention provide a wedge of air that generates a positive force on the trim strip in the area where the strip separates from the knife roll. This positively urges or moves the trim strip away from the knife roll and towards the scrap reclamation trim tubes, which substantially eliminates or reduces the risk that the trim will adhere to the knife roll and cause time consuming and expensive production problems. Moreover, unlike the Reba et al system, it does not require critical location of the nozzles in areas that are unsuitable for current slitters.
[0028] Of course, those skilled in the art will understand that many modifications may be made in this system within the scope of this invention, which is defined by the following claims. | A slitter for webs, such as sheet aluminum or other metals, has a simple and effective method and apparatus for controlling the movement of a strip of metallic trim into a scrap reclamation system. One or more air nozzles direct a stream of air between the knife roll and the trim strip in the area where the trim strip leaves the knife roll. This presses the trim strip away from the knife roll, and reduces the risk that trim will adhere to the knife roll and cause problems. | 8 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a magneto-thermal device for causing a safety switch to open when the current which flows therethrough presents either an excessive instantaneous current or a smaller current but of too long a duration; this device comprises a bimetallic strip, a magnetizable yoke with which are associated: on the one hand, a screwed adjustable core which is surrounded by a coil and, on the other hand, a plate angularly movable about one end of the yoke for cooperating with one end of said core placed substantially at the same level and against a return spring, and locking means associated with said core for providing the adjustment position.
Such devices are widely used in apparatus, generally called thermal relays, which are intended for monitoring the currents flowing in a load, particularly in an electric motor, for interrupting its power supply when the current which it consumes takes on abnormal values.
2. Description of the Prior Art
In devices whose construction corresponds to the one mentioned above, it is necessary to adjust the core so that the intensity of the current which flows in the coil causes the plate to be attracted when a well-defined current threshold is reached; this current threshold which is determined as a function of the characteristics proper to each motor, causes tripping, as a function of the different geometrical parameters of the coil, of the magnetic circuit and of the return spring, which are subject to slight variations during mass production; furthermore, an adjustment carried out in the factory so that the finished apparatus has the desired protection properties, must be kept during fitting and thereafter when either mechanical or thermal stresses or ageing of the materials of the apparatus or of its case appear.
Among the adjustments whose importance is preponderant are those which influence the dimensions of the air-gaps which exist between the end of the core, the plate and the end of the yoke; modification of the first of these air-gaps must especially not influence the second one. In some known devices, adjustment of the respective position of the active end of the core and of the plate is provided by moving an opposite threaded end into a threaded opening in the yoke, whereas locking of the chosen adjustment is provided by means of a locknut which is engaged against this threaded end. Such a known device has the disadvantage of a drive being possibly communicated to the core at the time when a locking torque is communicated to the nut; when the pitch of the thread is fine, such a drive is small, but, even in this case, it is not excluded that the locking forces may cause a slight lateral movement of the active end and modify the leak air-gap which exists between it and the end of the yoke.
The invention consequently provides a device conforming to the one whose construction is mentioned above but in which measures will be taken so that the means for locking the core do not modify the lateral position of the active end of the core and ensure permanence of the adjustment effected.
SUMMARY OF THE INVENTION
According to the invention, the desired result is obtained because, in a plane perpendicular to the axis of the core and adjacent the end of the yoke serving as a pivot for the plate, a flat non magnetizable piece is placed under radial compression between the end of the core and a face of the leg of the yoke situated opposite, the radial dimension of this piece being slightly greater than the distance which separates said end and said face in the absence of said piece.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention, as well as complementary measures for facilitating the whole of the adjustments of the device and for simplifying manufacture thereof, will be better understood from reading the following description.
In the accompanying drawings:
FIG. 1 represents a schematical view of the device associated with a protection apparatus;
FIG. 2 is an elevational view of the device;
FIG. 3 is a side view of the device of FIG. 2;
FIG. 4 is a view of the device in partial section through plane PP' of FIGS. 2 and 3; and
FIG. 5 shows an enlargement of the upper region of the magnetic relay.
DESCRIPTION OF THE PREFERRED EMBODIMENT
A magneto-thermal device 1, shown in FIG. 1, is for example disposed inside a protection apparatus 2, so that a current flowing through a load and between terminals 3 and 4 passes through a magnetic relay 5 and a bi-metallic strip placed in series. A mobile plate 33 of this relay and a mobile end 6a of said bi-metallic strip transmit the movements or deformations which they undergo (possibly through retarder means 7 or association means 8 common to several identical bi-metallic strips) to a quick-trip mechanism or member 9 whose release causes a safety switch 10 to open. The terminals of this switch, which have not been shown, are themselves associated with a control circuit adapted for establishing or interrupting the power supply of the load, in a known way.
Relay 5, shown in FIG. 2, comprises a magnetizable yoke 11 having two perpendicular legs 12 and 13, the shortest of which 12 is, in the embodiment shown, welded to a support plate 14. One of the pieces 12 or 14, or even both, have a fine pitch threaded opening 15 with axis XX' which is adapted to receive a first threaded end 16 of a magnetizable core 17, a second opposite end 18 of which is substantially opposite an end 19 of leg 13.
On this core is fitted an insulating shell 20, on which a winding 23 is wound between two flanges 21,22 of the shell. The lower flange 21 adjacent leg 12 supports a conducting piece 24 which is associated with terminal 3 and is welded to one end 25a of the wire of the coil.
The upper flange 22 has, in a plane PP' adjacent end 19 and substantially perpendicular to the axis XX', see FIGS. 4 and 5, a groove 26 which is open in the direction of the internal face 27 of leg 13 and which extends as far as the inner bore 28 of the shell. This groove, which is open laterally at least towards one side 29 of flange 22, see FIG. 4, receives a flat metallic non magnetizable piece 30 made for example from aluminium, brass or stainless steel. This piece, which may slide in the groove in the manner of a wedge 32, has a radial dimension "d" greater than the distance separating face 27 of the cylindrical surface 31 of core 17 placed opposite, this distance being measured when piece 30 is not fitted.
The result is that this piece 30 is placed under compression when it is in position, or when the core 17 is subjected to a stress perpendicular to the axis XX'; a resilient jamming effect of core 17 is then caused in the region where the threaded end 16 and opening 15 cooperate.
When, in the absence of complementary measures, a rotation is communicated to the core so as to modify the value of the working air-gap Et which separates the end 18 from a mobile plate 33, there is a risk of wedge 32 sliding in groove 26 because of the friction force which is communicated thereto.
Piece 30 comprises consequently a bevelled region 34 which is followed first of all by a notch 35, then by a rectilinear wall 36; said wall and said bevelled region have widths "e" slightly greater than the distance "d"; engagement of piece 30 is effected in the direction of arrow F while producing slight resilient deformation of the core and of leg 13, until notch 35 snaps on to surface 31 of the end 18 of core 17.
The magnetizable plate 33 which was mentioned above pivots about an edge 37 placed at the end 19 of leg 13, perpendicularly to axis XX' and is subjected to a return force delivered by a spring 38.
Holding this plate and guiding it in the rest position are achieved, on the one hand, by a tongue 39 which is placed in the axial extension of leg 13 so as to pass through an aperture 40 in this plate and, on the other hand, by means of two lugs 41,42 which laterally surround this latter, see FIGS. 3 and 5.
So as to ensure the quality of the pivot formed by edge 37, the two lugs 41,42 are carried by a flat cutout piece 43, which is fixed to the outer end 44 of leg 13, for example by spot-welds 45; a slot 46, which is located between lugs 41,42 at the upper part, is placed lower than edge 37 and at a level such that no material contact is established with the lower face 48 of this plate. The presence of this piece 43 has been used to serve as an adjustable support for the bi-metallic strip 6, because of the bent shape which it has been given.
The transverse portion 47 of piece 43 with lugs 41,42 and the spot-welds 45 is connected to a substantially perpendicular extension 49 by a constricted portion 50. This constricted portion is adjacent a first bent tab 51 which is connected to the end 25b of the winding passing through an indentation 52 in leg 13 of the yoke, whereas a second bent tab 53, equipped with a finger 54 for hooking thereon spring 38, is carried by the extension 49. Furthermore, one edge 55 of extension 49, which is slanting with respect to axis XX', is placed against the end 56 of the screw 57, whose axis is parallel to XX', which is engaged in a threaded opening 58 in plate 14. This plate comprises finally fixing means, not shown, which allow it to be associated rigidly with a fixed wall 59 of the apparatus. The position of the upper end 6a of the bi-metallic strip 6, which is parallel to axis XX', and whose lower end 6b is fixed to tab 53, may be adjusted in the direction G through a lateral movement effected by edge 55 when screw 57 is moved along its axis; this movement is made possible by the resilient deformation which the constricted portion 50 may undergo. The distribution of the magnetic masses of the yoke and of the plate is not substantially modified by the movements of the extension 49 because of the position of this latter against the external face 44 and because of the presence of wedge 32, whereas the presence of the transverse welded portion 47 of piece 43 in the region of plane PP' confers on region 19 of leg 13 a rigidity which might have been compromised by the presence of the indentation 52.
In a way known per se, a first end of a heater 6c is connected to the end 6a of the bi-metallic strip, whereas a second end 6d is connected by a conductor 60 to terminal 4, see FIGS. 2 and 3.
The angular movement of plate 33 is communicated, in direction L, by a pusher 61 integral with a plastic material cover 62 which is fixed to this plate.
It can be seen, in particular from FIG. 4, that the leak flux which passes through the air-gap E f keeps, because of the presence of wedge 32, a well-defined value, even if the fixing means for associating relay 5 with case 59 of the apparatus or the action of screw 57 on leg 13 produce slight deformations of the yoke. Finally, if it is desired that axis XX' of the core be perfectly parallel to the plane of leg 13 of the yoke, after positioning of the wedge, the axis of the threaded opening 15 may be given a direction forming with this plane, and before positioning of the wedge, a small angle whose apex is placed on the side opposite this opening. | The invention provides a magneto-thermal device for overcurrent relays.
The end of a core, whose axial position may be adjusted with respect to a mobile plate, placed opposite and pivoting about one end of the yoke, is secured against movement by a wedge which is guided in a groove belonging to a flange of the coil shell.
This device may be used in any thermal relay where a stable and precise adjustment of the tripping current threshold is desired. | 7 |
FIELD
The present invention broadly relates to communication over public computer networks. Specifically, the present invention relates to unidirectional links conforming to Intermediate System-to-Intermediate System routing protocols.
BACKGROUND OF THE INVENTION
Intermediate System-to-Intermediate System (IS-IS) is a routing protocol developed by the International Standards Organization (ISO). IS-IS is a link-state protocol and behaves much like the Open Shortest Path First (OSPF) protocol. IS-IS was developed as part of the Open System Interconnection (OSI) stack of protocols and uses OSI protocols to deliver packets and establish adjacencies. IS-IS routers need to be assigned OSI addresses, which they use as router identifiers to create network structure. IS-IS has been adapted to carry IP network information, and this form is called Integrated IS-IS. Integrated IS-IS has the most important characteristic necessary in a modern routing protocol: It supports VLSM and converges rapidly. It is also scalable to support very large networks.
IS-IS floods a network with link-state information to build a complete, consistent picture of a network topology. To simplify router design and operation, IS-IS distinguishes between Level 1 and Level 2 ISs. Level 1 ISs communicate with other Level 1 ISs in the same area. Level 2 ISs route between Level 1 areas and form an intradomain routing backbone. Hierarchical routing simplifies backbone design because Level 1 ISs need to know only how to get to the nearest Level 2 IS. The backbone routing protocol can also change without impacting the intra-area routing protocol.
IS-IS uses a single required default metric with a maximum path value of 1024. The metric is arbitrary and typically is assigned by a network administrator. Any single link can have a maximum value of 64, and path links are calculated by summing link values. Maximum metric values were set at these levels to provide the granularity to support various link types while at the same time ensuring that the shortest-path algorithm used for route computation is reasonably efficient. IS-IS also defines three optional metrics (costs): delay, expense, and error. The delay cost metric reflects the amount of delay on the link. The expense cost metric reflects the communications cost associated with using the link. The error cost metric reflects the error rate of the link. IS-IS maintains a mapping of these four metrics to the quality of service (QoS) option in a Connectionless Network Protocol (CLNP) packet header. IS-IS uses these mappings to compute routes through a public network.
IS-IS uses three basic packet formats: IS-IS hello packets, link state packets (LSPs), and sequence number packets (SNPs). Each of the three IS-IS packet types has a complex format that includes an 8-byte fixed header, a packet type-specific portion having a fixed length, and a packet type-specific portion having a variable length.
IS-IS uses type length value (TLV) parameters to carry information in LSPs. These TLVs make IS-IS extendable. IS-IS can therefore carry different kinds of information in LSPs. In an embodiment, IS-IS supports only CLNP. However, IS-IS was extended for IP routing with the registration of TLV 128 that contains a set of 12-octet fields to carry IP information.
In the IS-IS protocol data unit (PDU), there is a fixed part and a variable part of the header. The fixed part of the header contains fields that are always present, and the variable part of the header contains the TLV that permits the flexible encoding of parameters within link state records. These fields are identified by one octet of type (T), one octet of length (L) and “L” octets of value (V). The type field indicates the type of items in the value field. The length field indicates the length of the value field. The value field is the data portion of the packet. Not all router implementations support all TLVs, but they are required to ignore and retransmit the ignored types.
TLV 128 extends IS-IS to carry IP, in addition to connectionless network service (CLNS), routing information in the same packet. Several routing protocols use TLVs to carry a variety of attributes. Cisco Discovery Protocol (CDP), Label Discovery Protocol (LDP), and Border Gateway Protocol (BGP) are examples of protocols that use TLVs. BGP uses TLVs to carry attributes such as Network Layer Reachability Information (NLRI), Multiple Exit Discriminator (MED), and local preference.
There are network deployments where a link is unidirectional (UD) but there is a requirement for routing protocols to forward traffic over it. There is a need to extend routing protocols such as OSPF and IS-IS to run directly over unidirectional links (UDLs).
IP encapsulation is used for tunneling across a communication network of routers. An inner IP header is encapsulated by an outer IP header for the tunneling configuration. The outer IP header is added before the original IP header. Between them are any other headers for the path, such as security headers specific to the tunnel configuration. The outer IP header source and destination identify the endpoints of the tunnel. The inner IP header source and destination identify the original sender and recipient of the datagram. Each header chains to the next using IP Protocol values.
A send-only interface is a router interface that can only transmit. Likewise, a receive-only interface is a router interface that can only receive. The path from receive-only to send-only may be multi hop and can go further through other unidirectional links (UDLs). There is a need to support IS-IS over multi-hop return path without any IP encapsulation and in presence of other UDLs to eliminate the overhead and complexity of IP encapsulation.
SUMMARY OF THE INVENTION
The present invention supports the operation of IS-IS over UDLs without the need for encapsulation of IS-IS PDUs in IP and without the need for a large-scale upgrade of the protocol in the network. The present invention also supports adjacency establishment when the return path from the router at the receive end of a unidirectional link (referred to herein as Router R) to the router at the transmit end of the unidirectional link (referred to herein as Router T) is via another unidirectional link.
The present invention uses TLV information in LSPs to establish adjacencies. The present invention includes three-way handshaking information and MAC address information as sub-TLVs of a new UDL TLV to carry information that is used to establish the adjacency. This supports dynamic creation of adjacencies over a UDL without the need for static configuration of neighbor information.
The present invention uses a return path calculation from router R to router T that does not traverse the UDL between router T and router R to maintain the adjacency from T's perspective. In the absence of some form of encapsulation or tunneling, hellos cannot be sent from router R to router T. Some other mechanism is therefore required in order to detect loss of connectivity on the return path from router R to router T. The present invention utilizes a return path calculation from router R to router T to detect loss of connectivity. This calculation only is required when a topology change occurs in the network. It therefore need only be done in conjunction with a normal event driven SPF calculation.
The present invention uses special flooding rules for UDL-LSPs over a UDL on which no adjacency is yet established. Sending UDL-LSPs periodically over a UDL (even when the link is UP but adjacency is not UP) allows the return path from router R to router T to be via one or more UDLs on which an adjacency may also be in the process of coming up.
The present invention uses LSP TLV information to act as a LAN PSNP equivalent. This, in conjunction with periodic CSNPs, provides reliability to the flooding of LSPs over a UDL by allowing the receive-only router to request LSPs from the transmit-only router when it detects that the two databases are out of synchronization. The likelihood that such synchronization is required is low and therefore delays are defined so as not to unnecessarily utilize this mechanism.
The present invention does not require IP encapsulation nor rely on bidirectional forwarding detection (BFD) to maintain adjacency. The present invention avoids IP encapsulation by performing reverse SPF from receive-only nodes in order to check if there is a path from a receive-only node to a send-only node to maintain the adjacency between the two nodes. Flooding is performed over a UDL in a manner similar to a broadcast circuit where T operates as the DIS and R is not required to send acknowledgements. The present invention also provides support of UDLs in the presence of a UD return path.
The present invention utilizes routers on the receive end of a UDL to reserve at least one LSP fragment other than LSP fragment #0 (at each level if appropriate) for advertising the UDL information described below. An LSP fragment containing one or more UDL TLVs is referred to as a UDL-LSP. The only TLVs that are advertised in these fragments are the UDL TLVs described below and an Authentication TLV (10). This is enforced by the originator of the LSP fragment but is not checked by receiving systems. Routers on the transmit side of a UDL flood UDL-LSPs regardless of the existence of an adjacency in the UP state on that circuit.
Other features and advantages of the present invention will be realized from reading the following detailed description, when considered in conjunction with the drawings, in which:
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates a network of routers in accordance with the present invention;
FIG. 2 illustrates in block diagram form the major components of a router in accordance with the present invention;
FIG. 3 illustrates in flow chart form a sequence of acts performed in accordance in an embodiment of the present invention; and
DETAILED DESCRIPTION
Directing attention to FIG. 1 , there is shown an exemplary network of routers in accordance with the present invention. Routers R 1 -R 4 function to pass traffic in the form of packetized data between points 100 , 200 . Points 100 , 200 can be individual, end user computer systems, local area networks, wider area networks, and may even be separate computer networks containing additional routers, but in each case data packets are sent through at least some of the routers R 1 -R 4 between points 100 , 200 . While FIG. 1 illustrates a network having a specific number of routers R 1 -R 4 , it is to be understood that various configurations of routers can be implemented in accordance with the present invention. Such variations include the number of routers included, as well as the communication medium employed between the routers. Routers R 1 -R 4 can communicate with each other over wireless media as well as wired media, as can points 100 , 200 .
Arrows between routers in FIG. 1 illustrate the presence of a UDL. Lines appearing between routers in FIG. 1 without arrowheads denote bidirectional links.
FIG. 2 illustrates an exemplary embodiment of at least one of routers R 1 -R 4 that incorporate the functionality of the present invention. Router 202 includes communication connection 210 , processor 212 , memory 214 , link state database 216 , and shortest path data structure 218 . Other components, commonly found in routers known to those skilled in the art, are included in router 202 , but are not illustrated.
In accordance with embodiments of the present invention, the following information may appear in a UDL-LSP:
x TLV Type − TBD (UDL three-way adjacency
information)
x Length (8 + ID Length) − 255
x Value − UDL three-way Adjacency Information
uniquely identifying a neighbor at the
transmit end of a UDL
+------------------------------------+
| Extended Local Circuit ID | 4
+------------------------------------+
| Neighbor System ID | ID Length
+------------------------------------+
| Neighbor Extended Local Circuit ID | 4
+------------------------------------+
SubTLV Type − 6 (UDL LAN Address)
x Length − 6
x Value
+------------------------------------+
| Local LAN Address | 6
+------------------------------------+
x SubTLV Type − 9 (UDL LSP Entries)
x Length − (10 + ID Length) * N
x Value − A list of N entries of the following
format
+------------------------------------+
| Remaining Lifetime | 2
+------------------------------------+
| LSP ID | ID Length + 2
+------------------------------------+
| LSP Sequence Number | 4
+------------------------------------+
| Checksum | 2
+------------------------------------+
Router T advertises the cost to its UDL neighbor based on the locally configured value. Router R advertises the cost to its UDL neighbor as the maximum link metric (2^24−1). This precludes other routers from including the path from router R to router T in their SPF calculations. Directing attention to FIG. 3 , at act 302 , router T initiates adjacency establishment by sending point-to-point IS-IS hello (IIH) PDUs over the UDL as normal, including three-way Handshake TLV (240). The local circuit ID specified by router T need only be unique among the set of UDL circuits router T is configured to support on which router T is at the transmit end.
At act 304 , upon receipt of an IIH PDU, router R creates an adjacency in the INIT state with router T and advertises the existence of the adjacency in its UDL-LSP(s) on the return path to router T through flooding. It sends the three-way UDL information for the neighbor, but no LSP entries. The UDL-LAN address sub-TLV is included if the circuit is a LAN. UDL-LSPs of the appropriate level(s) are generated according to the type of the adjacency with router T. At act 306 , when router T receives the LSP fragment(s) from router R containing the UDL three-way adjacency information, it validates the three-way information and transitions its adjacency to UP state. In subsequent IIH PDUs, router T includes router R's circuit ID information as indicated in the UDL three-way TLV in its three-way handshake TLV (240). At act 308 , a complete set of complete sequence number packets (CSNPs) is sent to router R and router T propagates its LSP Database to router R for the level(s) appropriate for the type of adjacency. At optional act 310 , partial SNPs are communicated between router T and router R.
Router R uses normal adjacency to bring up rules based on the three-way handshake information it receives in IIH PDUs from router T and advertises its IS neighbor to router T in the usual manner i.e. in an LSP fragment other than its UDL-LSP fragment.
For purposes of LSP propagation, router T views the UDL as a broadcast subnetwork where router T is the designated intermediate system (DIS). Therefore, router T propagates new LSPs on the UDL as they arrive but after sending an LSP on the UDL the SRM bit for that LSP is cleared i.e. no acknowledgement for the LSP is required or expected. Router T also sends periodic CSNPs on the UDL.
Router R does not propagate LSPs to router T on the UDL. Router R also does not acknowledge LSPs received from router T on the UDL. In this respect, router R operates on the UDL as a non-DIS on a broadcast circuit. If an LSP entry in a CSNP received from router T identifies an LSP that is newer than an LSP in router R's database, router R may request the LSP from router T by sending a UDL-LSP with an LSP entry as described above. Router R's UDL-LSP will be propagated throughout the network even though the information is only of use to router T. In order to minimize the need for generating new UDL-LSPs, it is recommended that some small delay occur between the receipt of a CSNP from router T and the generation of a UDL-LSP by router R so as to allow for the possible receipt of the LSP either from router T or on another circuit.
On receipt of a UDL-LSP generated by router R, router T checks the three-way adjacency information in each TLV. If the information matches an existing adjacency that router T has with router R then router T sets send routing message flag (SRMflag) on the UDL circuit for any LSPs in its database that are newer than the corresponding entries router R sent in the UDL TLV. UDL information about adjacencies with routers other than router T is ignored by router T.
If all return paths from router R to router T traverse a UDL, then in order to bring up the adjacency between router T and router R, the adjacency on a return path UDL must already be UP. This is required because router T relies on receiving the UDL-LSP generated by router R in order to bring up its adjacency. In order to overcome a circular dependency in the case where multiple pairs of UDL neighbors are trying to bring up an adjacency at the same time, an extension to LSP propagation rules is required. Router T must periodically propagate UDL-LSPs on all UDLs whenever no return path from router R to router T can be calculated by router T (thus there is no adjacency between router R and router T). It is recommended that UDL-LSP(s) be sent at the configured CSNP interval.
Router R must accept and propagate UDL-LSPs received on a UDL even when there is no adjacency in the UP state on the UDL circuit. Flooding of UDL-LSPs by router R uses normal flooding rules. LSPs received by router R on the UDL that do not include UDL TLVs are discarded unless the adjacency is UP (as in normal processing).
Router T sends IIH PDUs as normal. In addition, router T sends periodic CSNPs over the UDL as it would if it were the DIS on a broadcast circuit. As router R cannot send IIH PDUs to router T, router T maintains the adjacency to router R so long as router T has a valid UDL-LSP from router R which includes valid three-way UDL adjacency information regarding the adjacency router R has with router T on this circuit, and router T can calculate a return path rooted at router R back to router T which does not traverse the UDL circuit with which the adjacency is associated. When either of the above conditions is not met, router T brings down its adjacency to router R. Immediately after the adjacency to router R has come up, if the only available return path traverses a UDL circuit on which the adjacency is still in the process of coming UP, the return path check will fail. This is possible because normal flooding rules are suspended to allow the UDL-LSP to be flooded even when the adjacency is not UP on a UDL link. If router T immediately brings the adjacency to router R down in this case, a circular dependency condition arises. To avoid this, if the return path check fails immediately after the adjacency comes up, a timer Tp is started. The timer is cancelled when a return path check succeeds. If the timer expires, router T brings down the adjacency. A recommended value for the timer Tp is a small multiple of the estimated time necessary to propagate LSPs across the entire domain.
Router R maintains its adjacency with router T based on receipt of IIH PDUs from router T as normal. When router R receives a CSNP from router T that contains an SNP entry identifying an LSP fragment which is not in router R's database (including entries which are older than, newer than, or non-existent in router R's database), a timer Tf is started for each fragment. The timer Tf is cancelled if either the associated LSP is received by R on any circuit by normal operation of the Update process, or a subsequent set of CSNPs received from router T does not include the SNP entry. If any timer Tf expires R brings down the adjacency with router T.
In an alternative embodiment, a multi-hop BFD session is established between router T and router R to provide fast failure detection, making optional the calculation described above on T of a return path from router R to router T.
Router T floods UDL-LSPs periodically over all UD links whenever no return path from the router at the receive end of the UDL can be calculated. This extension allows establishment of an adjacency on a UDL even when the return path transits another UDL that is also in the process of bringing up an adjacency. The periodic nature of the flooding is meant to compensate for the unreliability of the flooding. After the adjacency is UP, router R can request LSPs from router T by putting LSP entries into UDL-LSP information—but that ability is not available until the adjacency is UP.
If all return paths from router R to router T traverse another UDL that is also in the process of bringing up an adjacency, it is possible that router T and router R will declare the adjacency between them as UP before a return path is confirmed. This is necessary to avoid a circular dependency. Although it is unorthodox to bring up an adjacency without confirmed two-way connectivity, the extension is well grounded because the receipt of router R's UDL-LSP by router T is indicative of the existence of a return path even though it cannot yet be confirmed by examination of the LSP database. This unconfirmed, two-way connectivity is a condition that is should not be allowed to persist indefinitely—hence the need for timer Tp.
In an alternative embodiment, router R generates and floods a new UDL-LSP each time it receives an IIH from router T over the UDL. This provides a higher degree of confidence that the return path is still functional at the cost of periodic area/domain wide flooding of the new UDL-LSPs. Generation of the UDL-LSPs stops once router R calculates a return path from itself to router T. A timer Tp is used to limit the duration of the periodic flooding.
While preferred embodiments of a method and apparatus for supporting unidirectional links in Intermediate system-to-Intermediate System have been described and illustrated in detail, numerous modifications can be made to the present invention without departing from the spirit thereof. For example, a computer-readable medium may contain instructions which are executed by a computer. | The present invention supports the operation of IS-IS over UDLs without the need for encapsulation of IS-IS PDUs in IP and without the need for a large-scale upgrade of the protocol in the network. The present invention also supports adjacency establishment when the return path from a router at the receive end of a to the router at the transmit end of the unidirectional link is via another unidirectional link. | 7 |
The invention relates to integrated BiCMOS semiconductor circuits having active moat areas in silicon.
BACKGROUND
There are integrated BiCMOS semiconductor circuits that have active moat areas in silicon. These moat areas include electrically active components of the semiconductor circuit, the active components comprising active window structures for base and/or emitter windows. The semiconductor circuit has zones where silicon is left to form dummy moat areas which do not include electrically active components. The semiconductor circuit further has isolation trenches to separate the active moat areas from each other and from the dummy moat areas.
In the production of integrated BiCMOS semiconductor circuits, a plurality of silicon and oxide layers are deposited on a support wafer and patterned in consecutive steps. An example of such a stack of layers is shown in a schematic sectional view in FIG. 1 of the appending drawings. Upon patterning, stacks of layers, generally referred to as 1 in FIG. 1 , form so called active moat areas 2 . These areas are islands which will in the end contain electrically active components of the semiconductor circuit. The active moat areas 2 are separated by trenches 3 formed into the layers by etching. The trenches are filled with an isolating material 4 such as oxide. Above a trench 3 , a shallow depression 3 a may form in the oxide layer 4 . Depending on the layout of the circuit, the distance between two adjacent active moat areas 2 can be wide, resulting in a broad trench 5 . Where the trenches are too wide, deep depressions 6 in the oxide layer 4 will occur.
These deep depressions 6 become a problem when performing a process of chemical mechanical polishing (CMP) on a layer.
To avoid the occurrence of depressions in the oxide layer 4 , so called dummy moat areas 7 are left ( FIG. 2 ). These areas 7 are islands which are designed not to include electrically active components but simply to avoid large and deep depressions. Incidentally, the technique of leaving dummy moat areas 7 is known in the prior art to ensure correct planarization.
Anisotropic plasma etching is used for the etching of fine structures. The etching duration may be pre-determined, but if the underlying layer is thin, e.g., a thin oxide film, it is essential to stop the etching in time before the underlying silicon gets damaged, but not before the desired structure is completed. This is particularly essential when dealing with small structures. Due to inaccuracies in the thickness of the layer to be etched and in the etchant composition, the calculation of the etching duration cannot be exact. Still, the completion of the etching process can be controlled more accurately by detecting an endpoint in the process. As explained in the article entitled, “Tungsten silicide and tungsten polycide anisotropic dry etch process for highly controlled dimensions and profiles,” by R. Bashir, et al., in J. Vac. Sci. Technol., Vol. 16(4), July/August 1998, pages 2118-2120, and in U.S. Pat. No. 6,444,542B2, the endpoint of the etching process can be detected by a change in the composition of the optical radiation by optical emission spectroscopy, by the plasma characteristics, i.e., high-frequency harmonics, or the discharge current, or by a change in reflection properties of the wafer when the etching process reaches the underlying layer. Reaching an oxide layer can also be used as an endpoint check (U.S. Pat. No. 5,496,764A). But, if the surface to be etched is very small compared to the total wafer surface, detection of the endpoint of the etching process with this approach is no longer possible.
In U. S. Pat. No. 6,004,829A, it is proposed to enlarge the surface to be etched by inserting additional pad areas in forming an EPROM device. It is, however, well-known that large areas exhibit a higher etch-rate than small structures. If now the window structures to be etched are very small and delicate, and dummy surfaces are used for etch endpoint detection, the etch endpoint signal will occur prematurely, so that the optimum moment in time when the etching process should be terminated cannot be determined with sufficient precision.
SUMMARY
The invention provides an integrated BiCMOS semiconductor with accurately etched very small geometries.
Specifically, an integrated BiCMOS semiconductor circuit having active moat areas in silicon is provided. The active moat areas include electrically active components of the semiconductor circuit. The active components comprise active window structures for base and/or emitter windows. The circuit further has zones where silicon is left to form dummy moat areas which do not include electrically active components, and isolation trenches to separate the active moat areas from each other and from the dummy moat areas. The dummy moat areas comprise dummy window structures having geometrical dimensions and shapes similar to those of the active window structures for the base and/or emitter windows.
In the production process of this integrated BiCMOS circuit, the active window structures for base and/or emitter windows in the active moat areas and the dummy window structures within the dummy moat areas having similar geometrical dimensions and shapes are formed simultaneously. The total surface area of the window structures which are exposed to the etchant is importantly in-creased by having both active and dummy window structures. Hence, a signal for the endpoint detection can be detected much more clearly than in a case where only small active window structures are etched. Since the dummy window structures are of similar geometrical shape and dimension as the active window structures, the signal for the detection of the etching endpoint for the small structures is distinct and not blurred by the effect of a different etching characteristic as it would be, if coarse or large dummy structures were used. So the optimum moment in time when the etching process shall be terminated is precisely determined by the endpoint signal. The integrated circuit according to the invention can be manufactured with high precision, avoiding over etching and large under-cutting which would otherwise result in an increase in emitter-base leakage, an enlarged emitter size and in the end cause a large variability in bipolar parameters. The proposed integrated circuit provides for reliable etch endpoint detection of very small structures independent of structure size.
The total surface of the dummy window structures should preferably exceed that of the real window structures by at least one order of magnitude, thereby to increase the precision of the determination of the completion point of the etching process.
In an embodiment of the invention, the dummy window structures in those layers in which active base windows are formed in the active moat areas and the dummy structures in those layers in which active emitter windows are formed in the active moat areas, are stacked within the dummy moat areas. This provides for a very economic use of moat area. The reliable etch endpoint detection scheme can be extended to a checkerboard pattern to allow a total of four sequential end-pointed etch processes, namely emitter and base openings for NPN and PNP, without requiring additional moat area.
BRIEF DESCRIPTION OF THE DRAWINGS
Example embodiments of the invention are described, with reference to the accompanying drawings, wherein:
FIG.1 is a schematic sectional view through a first integrated semiconductor circuit from the state of the art.
FIG. 2 is a schematic sectional view through a second integrated semiconductor circuit from the state of the art.
FIGS. 3-6 are schematic sectional views through an integrated semiconductor circuit according to the invention, in successive steps of a production process.
FIG. 7 is a schematic sectional view through an integrated semiconductor circuit, including a plurality of dummy window structures.
FIG. 8 shows the layout of the set of dummy window structures of FIG. 7 .
FIGS. 9A-9C are three graphs, illustrating signals resulting from monitoring the composition of the etching medium, on the basis of the characteristic plasma emission, recorded against time.
DETAILED DESCRIPTION
FIGS. 3-6 illustrate an integrated BiCMOS semiconductor circuit 10 according to the invention in a photolithographic production process.
In FIG. 3 , the integrated semiconductor circuit 10 is shown in a cross-sectional view. The integrated semiconductor circuit 10 is at an intermediate process stage and has already undergone several process steps which are known to those skilled in the art, further description of which is not needed for understanding the invention.
In the illustrated process stage, the integrated semiconductor circuit 10 comprises a support wafer 12 covered by a buried oxide layer (BOX) 14 . The BOX 14 supports a single-crystal silicon layer 16 . The silicon layer 16 is divided into islands 18 , forming active moat areas 20 , which will in the end contain electrically active components (not shown in the figures) of the semiconductor circuit. The islands 18 are separated by deep trenches 22 and shallow trenches 24 , filled with oxide to isolate the active moat areas 20 from each other. Further islands are remaining, forming dummy moat areas 26 to ensure correct planarization in a process of chemical mechanical polishing (CMP). On top of the active moat areas 20 and the dummy moat areas 26 , a thin gate oxide film 30 is grown and then covered by a thin polysilicon layer 32 . The thin polysilicon layer 32 comprises the first part of CMOS polysilicon gates on the chip.
The creation of dummy structures in the dummy moat area 26 is explained below.
In FIG. 4 , the polysilicon layer 32 is patterned and etched to provide base window structures (not shown) in the active moat areas 20 . The etching must be complete and must be stopped immediately when the gate oxide 30 is reached. Therefore, according to the principles of the invention, dummy base window structures 34 are created in the dummy moat areas 26 simultaneously with the active base window structures in the active moat areas 20 . These dummy base window structures 34 have geometrical dimensions and shapes that are similar to those of the active base window structures in the active moat areas 20 .
After the base window structure patterning, the residual thin oxide film 30 is removed within the active base window structures and the dummy base window structures 34 ( FIG. 5 ), e.g., by wet etching. Then a base silicon/polysilicon layer is deposited. This deposit grows as a single-crystal silicon layer 36 over the exposed single-crystal silicon 16 in the active base window structures of the active moat areas 20 and in the dummy base window structures 34 of the dummy moat areas 26 , while it grows as a polycrystaline silicon layer 38 over the remaining polysilicon layer 32 and the exposed shallow trenches 24 . The silicon layers 36 , 38 are then covered with a screen oxide 40 in preparation for implantation and the next patterning step.
The screen oxide 40 is removed and an inter-poly insulator stack 42 deposited ( FIG. 6 ). The inter-poly insulator stack 42 comprises a thin oxide film 44 , covered by a nitride film 46 . Then a photoresist layer 48 is applied and patterned to create active emitter window structures 49 in the inter-poly insulator stack 42 . Again, it is important to detect the endpoint for this step, because a defined thickness of the oxide film 44 must remain in the active emitter window structures. Therefore, according to the principles of the invention, dummy emitter window structures 50 are created in the dummy moat areas 26 simultaneously with the active emitter window structures in the active moat areas 20 . Again, these dummy emitter window structures 50 have geometrical dimensions and shapes that are similar to those of the active emitter window structures in the active moat areas 20 .
In FIG. 6 , only one active emitter window 49 and one dummy emitter window 50 is drawn for the sake of a clear presentation. In practice, however, multiple active window structures 49 and dummy emitter window structures 50 are normally created, as it is shown by example in FIG. 7 .
FIG. 8 shows an example of a layout pattern 60 for a plurality of dummy emitter window structures 50 . Also shown in FIG. 8 is the outline of the dummy moat area in inner dot-dashed lines. Further the outline of the base poly-silicon layer 36 is indicated in outer dot-dashed lines, since the dummy emitter window structures 50 are stacked over the dummy base window structures. So, the dummy window structures for endpoint detection during the etching of active base windows and during the etching of active emitter windows can be arranged within the same dummy moat areas.
The dimensions a and b are determined by the minimal width of the active window structures on the chip. The length c of the dummy window structures is adjustable and depends on the size of the dummy moat.
The dummy base and/or emitter window structures, e.g., the layout which is illustrated in FIG. 8 , is preferably applied to as much dummy moat areas 26 as are available on the wafer. The proportion of the area occupied by the emitters on BiCMOS chips is far below 1%. The use of a significant number of dummy window structures can increase the proportion of the total surface available for etching to 3-5%. As a result, a signal from monitoring the etching process will have much more significant changes, when the small structures are completed, which allows a reliable detection of the optimum etch endpoint.
During an etching process according to the methods described above, the composition of the etching medium can be monitored by way of its characteristic plasma emission. FIGS. 9A-9C show schematically the composition of the etching medium monitored as a function of its characteristic plasma emission over time t for different configurations. The optimum end etchpoint for the small structures in the particular configuration is indicated in the Figures by T opt .
If according to the prior art, no dummy windows have been applied there will be no endpoint signal ( FIG. 9A ) when the etching medium reaches the oxide layer. The change in the composition of the etching medium cannot be measured, because the proportion of the area occupied by the active window structures only amounts to some parts in thousand, as compared to the total area available.
If large dummy areas without window structures are provided in the wafer, as already proposed in the literature, monitoring the etchant composition will show a signal like the one in FIG. 9B . The endpoint signal E 0 here occurs too early and prior to the optimum moment in time for the termination of the etching process of the small window structures, since the etching of large areas proceeds in a different way from that of thin window structures.
FIG. 9C shows that by using dummy window structures according to the invention, the optimum moment in time at which the etching process should be terminated can be determined with precision by means of the endpoint signal E 0 . | An integrated BiCMOS semiconductor circuit has active moat areas in silicon. The active moat areas include electrically active components of the semiconductor circuit, which comprise active window structures for base and/or emitter windows. The integrated BiCMOS semiconductor circuit has zones where silicon is left to form dummy moat areas which do not include electrically active components, and has isolation trenches to separate the active moat areas from each other and from the dummy moat areas. The dummy moat areas comprise dummy window structures having geometrical dimensions and shapes similar to those of the active window structures for the base and/or emitter windows. | 7 |
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is based on and hereby claims priority to German Application No. 10146221.2 filed on Sep. 19, 2001, the contents of which are hereby incorporated by reference.
BACKGROUND OF THE INVENTION
[0002] The invention relates to a device and a method, with which, for optical inspection of a flat surface of an object, its plane-parallel orientation to a focus plane of a lens belonging to a measuring head can be achieved. For optical inspection of objects or of object surfaces, such as for example the surface of wafers, the relevant optic features a significant magnification. Consequently the depth of field is relatively small. If this depth of field is smaller than the distance error which can occur for the distance between lens and object this leads to partly unsharp images. It is precisely in the inspection of large surfaces of an object that these distance tolerances arise to a greater extent. These distance errors are produced overall by plane-parallelism errors in the inspection table, object holder, for example chuck, and object in relation to the focus plane of a lens of a measuring head.
[0003] Previously known systems are essentially designed for the inspection of small surfaces of an object. In this case the image is focused using autofocus operation of a microscope of an inspection unit. Another option is to move the lens into the focused position. This involves fitting an adapter ring with an adjusting element between the lens and the microscope body. The adapter ring allows the distance between object and lens to be adjusted in such a way that the image is focused. A further option is to move the microscope manually, using an adjusting wheel for example, with the distance between lens and surface of an object being corrected so that the overhead view of the object plane is displayed sharply in the eyepiece or the camera chip of a camera connected downstream from the optics. For inspection of smaller object surfaces one-off focusing is sufficient as a rule.
SUMMARY OF THE INVENTION
[0004] An object of the invention is to provide a method and a device for plane-parallel orientation of a level extended object surface to a focus plane of a lens.
[0005] The invention is based on the knowledge that with a device and with a method corresponding to this patent application extensive, essentially flat areas can be optically inspected by a measuring head, with this being positioned at right angles to the axis of the optics present in the measuring head and with the features of the invention, allowing a very precise adjustment of the plane-parallelism between the focus plane of the optics and the surface to be measured to be achieved. In This case the elements of the device are provided to accept a flat extended body, for example a wafer or a frame, to hold it and for inspection of this extensive surface, to move it relative to a measuring head and possibly with its distance measurement system laterally in the x and y direction. For each state to be assumed here the current surface Image recording must be adjusted to be optically sharp.
[0006] By using three adjustment drives the adjustments to achieve plane-parallelism between the focus plane and the object surface are achieved. The adjustment drives, especially embodied as piezo actors, feature a typical adjustment range of 100 to 400 μm. An adjustment is made in the z direction which corresponds to changing a height value.
[0007] For each of the variants envisaged in the invention as a first step for all three surface points over which advantageously at least three adjustment drives are located in each case are focused using the optics of the measuring head and stored. To this end the measuring head his moved laterally over the relevant points and subsequently the adjustment elements lying below are adjusted in the z direction in such a way that optical focusing is achieved. If this process is executed at for example 3 adjustment elements on the surface to be inspected above them, this means for the object surface an overall plane-parallel alignment to a focus plane of the optics. Starting from this state in which the plane-parallelism of the planes is established only the surface of an object can be inspected.
[0008] Further indentations or protrusions on the surface of the object can require further error corrections. In an advantageous way a grid of support points is established on the surface in this way before the surface is inspected, in which case, for each support point the x, y data is known and using the equal height correction of all adjustment elements the system is moved to a z position of the current support point, which corresponds to optical focusing. Through this grid of support points which are known to the system error correction can be applied to sections for topographical errors on the object.
[0009] The advantageous use of a distance measurement system connected in parallel to the measuring head and also aligned to the surface of an object makes recording a grid of support points superfluous. After the first procedural step described above for plane-parallel adjustment of the surface of an object to a focus plane of the optics of the measuring head the distance to a measuring point with known x, y co-ordinate will be determined at regular intervals using the distance measurement system, in which case, during the relative movement between distance measuring system and measuring head on the one side and between the surface of an object first the measuring point is processed by the distance measurement system and through the available relative speed of movement and through the distance present between distance measurement system and measuring head the measuring head reaches the measuring point for inspection after a delay. This means that the distance measuring system can regularly determine new measuring points which, if they do not lie within an allowed range of tolerances, make it possible to correct errors.
[0010] Control is via the image information from a 2D camera or 1D camera, for example a scanning camera using contrast measurement. In this case the Area of Interest (AOI) is used in which the objects or parts of objects of interest lie. In this way, even if the height of the objects of interest shifts compared to their surroundings there is still sharp focusing.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] These and other objects and advantages of the present invention will become more apparent and more readily appreciated from the following description of the preferred embodiments, taken in conjunction with the accompanying drawings of which:
[0012] FIG. 1 is a schematic perspective view of a holder device for holding flat-profile objects, used for wafer inspection for example, and
[0013] FIG. 2 is a schematic perspective view of the entire inspection system with measuring head and optics, distance measurement system and piezo actors.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0014] Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout.
[0015] A system for inspection of wafer surfaces is described which allows a high-precision following of the surface of an object with an accuracy within the required depth of field. Tilting of the measuring table used can be compensated for, so that even within the image recorded the entire image area is sharp. In particular for inspection of larger surfaces with high inspection speed this method presented is superior to the optical autofocus principle or manual focusing.
[0016] To obtain plane-parallelism between a surface of an object and a focus plane of a lens in the measuring head, at least three adjustment elements, for example piezo actors 1 , 2 , 3 are used. Here the adjustment elements are integrated into the object holder. The object holder is for example represented by a chuck having upper and lower chuck plates. The adjusting elements 1 , 2 , 3 , represented by piezo actors are connected in between.
[0017] To set the plane-parallelism between focus plane and surface of an object, first, as part of a preliminary measurement, the object holder with the object is moved below the lens in such a way that the lens 7 is positioned over a piezo actor. By moving the piezo actor above which the lens is currently positioned focusing is achieved, i.e. the image that is produced in the camera in measuring head 11 is sharply focused. This process is repeated for each piezo actor or for a support point which is defined above the support surface of the object on the piezo actor. With this first procedural step the piezo actors are adjusted individually in such a way that when a support point is sharply focused the associated piezo actor moves the support point. Into the depth of field of lens 7 . After this routine is executed all errors which are generated by errors in the plane-parallelism are eliminated. Plane-parallelism is taken to mean the parallelism of two flat surfaces.
[0018] To control the object holder, the chuck, electronics are used which are at least partly accommodated in the object holder. This electronics includes for example the measurement amplifier for the integrated error correction of the adjusting elements, as well as the control system for these elements. The characteristics of these adjusting elements are as a rule not susceptible to hysteresis, so that for example a voltage applied to a piezo actor corresponds to an exact elongation of this actor.
[0019] To establish the plane-parallelism between focus plane and surface of an object at least three different randomly selected positions on the surface of an object can be selected. In principle adjustment with or without an object is possible, so that for example for the case in which the upper chuck plate 4 is not carrying an object the plane-parallelism between focus plane and upper chuck plate 4 can be established. This could be of importance for the case where a non-plane-parallel wafer is to be milled plane-parallel. Thus initially by the plane-parallel orientation of the upper side of the upper chuck 4 one side of a wafer lying on it is aligned so that it is plane-parallel. The upper side of a wafer moving at an angle to this can now be corrected.
[0020] An object 12 can be a wafer or a frame, with a frame being represented by a tensioning ring, with a wafer being glued to a foil.
[0021] The surface aligned after the first important procedural step is sampled in different positions within the context of a preliminary measurement and the measured values are used as a support points to determine the position of the surface of an object. The object is positioned over the measuring point. The image sharpness is measured and if the image is unsharp the entire object holder is raised or lowered evenly over the adjustment elements, piezo actors until the image is sharp. The z-position determined in this way is assigned to the support point. Using the support points thus determined a measurement path via x, y, z is determined for inspection of the object. The distance tolerances at and around the measuring point within the depth of field of the object lie in this path.
[0022] With an additional use of a distance measurement system which operates in conjunction with the adjustment elements and is arranged alongside the measuring head with the lens there is a further option for on-line correction, i.e. correction during operation. With this distance measuring system a unique distance measurement between lens and surface of an object or between lens and object holder is possible. If the object or an object point lies within the depth of field of the lens, with adjustment being undertaken via the adjustment elements, the measured value of the distance measurement system, is stored together with the lateral coordinates of the current measurement point as an operating point. With a subsequent calibration of an object the object holder is always moved in such a way over the piezo actors in connection with an internal adjustment that the operating point defined before the beginning of the measurement which represents a required value is also retained during the measurement. This means that the difference between the distance value recorded during the measurement, which corresponds to the actual value and the defined operating point, the required value is adjusted to a minimum.
[0023] The distance measurement system relative to the movement of a point on the surface below measuring head 11 is positioned in such a way relative to measuring head 11 that any point on the surface of the object obtained during an inspection first passes the distance measurement system and then, after a specific distance 8 , which corresponds to the distance between the distance measurement system and the measuring head, appears under the measuring head 11 . This means that points which were recorded by the distance measuring system are only recorded by the lens 7 of the measuring head 11 after a specific time with can be calculated from the path 8 and the speed of movement. The values determined by the distance measurement system are issued to the adjustment system after a delay so that the correction via the adjustment elements is then undertaken when the lens 7 travels over the measuring point. By using a number of distance sensors 6 tilting can be measured and corrected. Each adjustment element has its own control system so that for example a temperature drift can be compensated for.
[0024] The invention has been described in detail with particular reference to preferred embodiments thereof and examples, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention. | The orientation of the surface of an object to be examined is changed by adjusting the distance thereof to an optical measuring system in a plane-parallel manner in relation to a focusing plane of the optical measuring system, enabling high speeds of examination to be obtained during examination of the extended surfaces of the object. A distance-measurement system which is mounted in an auxiliary manner with regard to the measuring head enables fluctuations in the topography inside the surface of the object to be compensated in such a way that a currently received point or area can be optically sharpened. | 6 |
BACKGROUND
1. Field of the Invention
The present invention relates to the removal of metal vapor and submicron metal particles from combustion off-gas.
2. The Prior Art
Emissions of toxic metals, specifically, Cd, Pb, Hg, Ni, Sb, As, Ba, Be, Cr, Co, Mn, Se, Ag and Tl, into the air are regulated in the U.S. by the Resource Conservation and Recovery Act ("RCRA") and by the Clean Air Act.
Many wastes contain toxic metal constituents. Often, when these metals are associated with organic and aqueous components, incineration may be the preferred method of waste treatment and disposal. Incineration technologies can be effective in reducing waste volume and destroying organic elements. However, incineration cannot destroy the elemental metal constituents, although high temperature combustion environments will induce metal transformations. These transformations are usually thought to exacerbate their harmful effects, since many of the metal species formed readily vaporize within combustion environments, which vapor will nucleate and condense downstream of the flame, forming a fume of submicron aerosol. These particles, because of their small size, are difficult to collect in pollution control systems. Moreover, combustion gas in such incinerators often contains significant amounts of chlorine as Cl 2 and/or chloride compounds, the presence of which inhibits capture and removal of the metals. Chlorinated metal species that are collected often exhibit increased water leachability.
Using a downflow laboratory combustor, Scotto et al found that lead could be reactively scavenged in-situ by kaolinite powder which was injected into the postflame. See Scotto, M. V. Peterson, T. W., and Wendt, J.O.L. Twenty-Fourth Symposium (International) on Combustion, The Combustion Institute, Pittsburgh, 1992, pp. 1109-1117. Reactive scavenging (chemisorption) of a metal occurs at temperatures above the metal vapor dewpoint. Scotto et al also found that, although 99% of the lead could be captured by kaolinite, by reaction forming a lead aluminosilicate, the process was inhibited by the presence of chlorine.
Uberoi and Shadman investigated the use of kaolinite, bauxite, and limestone as sorbents to capture lead and cadmium. Their subcombustion temperature, fixed bed experiments, suggested that crystalline kaolinite might be somewhat less effective than crystalline bauxite in capturing cadmium because of pore closure observed in the cadmium/kaolinite system but not in the cadmium/bauxite system. For the lead/kaolinite system, the formation of a melt on the kaolinite surface appeared to enhance lead capture as lead aluminosilicate. Presence of a melt was also noted in the above-mentioned experiments of Scotto et al. Uberoi and Shadman also found that limestone was not an effective sorbent for either cadmium or lead.
Thus, previous research in this area has focused on the reaction of toxic metals and crystalline sorbents to form stable reaction products. Additionally, previous work has focused on low temperature applications such as those conditions common to flue gas cleaning environments. This has the disadvantage of limiting application to metal/sorbent systems where stable reaction products exist and limiting kinetic rates due to low temperatures. Previous research has been concerned not to expose sorbents to combustor conditions which would sinter or close pores and reduce effective surface area. One mechanism involves reaction between metal vapor and a sorbent crystalline surface, as in the reaction between cadmium and bauxite. Here, large pores prevent pore plugging by reaction products. This mechanism was identified by Uberoi and Shadman. See Uberoi, M., and Shadman, F., AIChE Journal, 36(2):307-309 (1990) and Uberoi, M., and Shadman, F., Environ. Sci. Technol., 25(7):1285-1289 (1991). However, metal sorption on crystalline sorbent surfaces is diminished when pores are plugged, as with cadmium/kaolinite, at moderately high temperatures.
Kubin et al--U.S. Pat. No. 5,092,254 discloses the injection of calcium based sorbents into a combustor for control of acid gases. In this process, great care is taken to avoid sorbent melting, in order to allow acid gas capture to take place. The reaction which is exploited in this process is one between acid gas constituents and crystalline surfaces, contained within a solid particle.
SUMMARY OF THE INVENTION
Accordingly, one object of the present invention is to exploit the high temperatures within conventional incinerators to transform potentially toxic metals into constituents that are both more easily collected and more environmentally benign than metal effluents.
Another objective is to provide for the foregoing without need for combustion modification.
Yet another objective is to provide a process for the effective removal of metal vapor from combustion gas even in the presence of a significant amount of chlorine.
To achieve the foregoing objectives, the present invention provides a process for the removal of vapor phase metal from a combustion gas. The process of the present invention involves contacting the combustion gas with a particulate fluxing agent heated to a temperature sufficient to form eutectic surface melt, the captured metal forming one component of the eutectic melt and the fluxing agent itself forming a second component of the eutectic melt. Optionally, another metal can be added to form a third component of the eutectic melt.
A preferred mode for contacting the combustion gas with the particulate fluxing agent is by introduction of the particulate flux into a combustion zone, containing the combustion gas, to form a suspension or "cloud" of the particulate flux within the combustion zone and thereby bring the particulate flux into contact with the vapor phase metal contained in the combustion gas. The "flux" or "fluxing agent" used in the present invention may be any flux conventionally used in metallurgy. Suitable fluxing agents include, but are not limited to, calcium carbonate, sodium carbonate, magnesium carbonate, hydrated lime, etc.
The preferred flux is at least one member selected from a group including calcium oxide, calcium hydroxide and calcium substances which are converted to calcium oxide and/or calcium hydroxide in the combustion zone. Almost any calcium containing compound will form the oxide or hydroxide in the combustion zone, e.g. calcium sulfate and calcium salts of organic acids.
Preferably, the particulate fluxing agent is injected into a location within the combustion zone where the temperature is sufficient to form a melt of a eutectic of the fluxing agent and at least one of the vapor phase metals on at least surface portions of the fluxing agent particles, thereby capturing the vapor phase metal in the eutectic melt. In the preferred approach, the injected particulate fluxing agent forms a gaseous suspension or cloud. However, other modes of contact, including use of a fixed or fluidized bed, may be feasible, particularly if the fluxing agent is admixed with non-fusible particles or adhered to a non-fusible support.
Metals which may be removed from vapor phase in accordance with the present invention include all of the previously mentioned "toxic metals" and, in particular, nickel, lead, cadmium and mercury.
In one aspect, the present invention involves the discovery that hydrated lime, for example, acts at a high temperature as an effective agent to scavenge cadmium which would otherwise contribute to the submicron aerosol fraction. These results are in contrast to those of Uberoi and Shadman. The present inventors have found, for example, that in the absence of cadmium, the lime particles remained crystalline, angular, and did not melt at the temperatures employed in their experiments. However, at the same temperatures and with the addition of cadmium, the calcium rich particles melted, forming a eutectic with the cadmium.
The process of the present invention differs from the prior art in that the metal vapor of the combustion gas is captured as one component of a eutectic surface melt on the fluxing agent particle rather than internally within the pores of a crystalline alumino-silicate sorbent or as a reaction product of the metal and the sorbent, e.g. lead alumino-silicate as in the work reported by Scotto et al. The eutectics employed in the present invention are physical admixtures, i.e. solutions, not products of a chemical reaction between a vapor phase metal and the fluxing agent.
The process of the present invention also differs from the prior art in terms of the affect of particle size. The efficacy of the prior art approaches is highly dependent upon sorbent surface area, with the rate of reaction being proportional to 1/d p , d p being the sorbent particle average diameter. In contradistinction, the efficiency of the process of the present invention appears to be fairly independent of particle size.
In general the prior art approach has been to promote the formation of crystalline stable metal/sorbent chemical reaction products. This necessitates that the sorbent not be subjected to conditions which would damage its pore structure or reduce its effective surface area. In contradistinction, this invention seeks to promote flux particle melting through injection into high temperature combustor locations and to thereby form metal/flux eutectic melts. These melts may be comprised of metals and a flux which would not form stable reaction products (cadmium and lime, for example). This has the advantage of expanding the utilization of the fluxing agent or "sorbent" to a larger set of toxic metals.
Yet another distinguishing characteristic of the present invention is that, in contrast to the findings of Scotto et al, the process is not adversely affected by the presence of significant amounts of chlorine in the combustion gas. In point of fact, the presence of chlorine in the process of the present invention actually enhances the capture of certain "non-volatile" metals such as nickel. This is an important advantage of the present invention because incinerator combustion gas typically contains significant amounts of chlorine.
The process of the present invention also differs from that of Kubin et al in its production of a melt on the particle surface. This melt solubilizes toxic metals but not acid gases. Therefore, were this melt to be formed during the process described in U.S. Pat. No. 5,092,254, acid gas capture would not occur and the process would have no value, as far as the objective of Kubin et al, i.e. acid gas capture, is concerned.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic illustration of a horizontal tunnel combustor as used in the examples described below;
FIG. 2 is a schematic illustration of a burner element as used in the combustor of FIG. 1;
FIGS. 3A and 3B are graphs showing experimental results for a nickel/kaolinite/chlorine system;
FIGS. 4A and 4B are graphs showing experimental results for a lead/kaolinite/chlorine system; and
FIGS. 5A and 5B are graphs showing data for a cadmium, kaolinite, kaolinite/chlorine system.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The terms "fluxing agent" and "flux", as used herein, define any material which will form, at least on its surface, a eutectic melt in combination with one or more of the metals to be removed from the combustion gas. The "fluxing agent" or "flux" utilized in the present invention might also be characterized as a "sorbent" in the sense that it dissolves or absorbs metals from the gaseous phase into a eutectic melt. The terms "eutectic" and "eutectic melt" as used herein have reference to a physical admixture of the fluxing agent and at least one metal derived from the combustion gas and are thereby distinguished from a product of a chemical reaction between the fluxing agent and the metal component or components. The "eutectic melt" of the present invention can also be characterized as a solution of the captured metal in the liquified flux. The "eutectic" utilized in the present invention will invariably have a melting point lower than that of the fluxing agent alone. It is contemplated that most, if not all, fluxing agents used in conventional metallurgical practices are suitable for use in the present invention.
The effect of the present invention has been observed at measured temperatures as low as 1500° Kelvin. However, certain eutectics within the scope of the present invention may have melting points as low as about 1000° K. Accordingly, the operating temperature will be at least 1000° K. In general, a sorbent temperature range of about 1000° K to 2000° K is contemplated. However, the important aspect of temperature in the context of this invention is that the temperature be sufficient to form a eutectic melt of the fluxing agent with one or more metals present in the combustion gas, at least to the extent of forming the eutectic melt as a surface melt on the particle surfaces.
As noted above, particle size plays little or no part in the present invention. This was confirmed experimentally in the experiments described below. In the experiment reported below employing hydrated lime, which is within the scope of the invention, the mass mean diameter of the particulate hydrated lime was 2.24 microns.
The fluxing agent can be injected into the combustion zone in any conventional manner, for example, using the air transport screw feeder employed in the experiments described below. As noted above, it may be feasible to contact the combustion gas with the fluxing agent in the form of a packed bed, in the form of a fluidized bed or in the form of a coating on a monolithic, non-fusible support, e.g. a ceramic honeycomb.
Optionally, at least a third metal may be added in order to further depress the melting point of the eutectic. Suitable metals include, but are not limited to, the alkaline earth metals (the elements of Periodic Group IIA--Be, Mg, Ca, Sr, Ba and Ra), the alkali metals (the elements of Periodic Group IA--Li, Na, K, Rb, Cs and Fr), boron and iron (FeO). One or more of these additional metals may be introduced into the eutectic melt by adding the metal or metals and/or a compound or compounds thereof to the combustion system. For example, a compound or compounds of one or more of these metals may be used to impregnate the fluxing agent. A compound or compounds of the additional metals may, in the alternative, be introduced into the combustion zone in the form of powder particles separate and apart from the fluxing agent particles or may be added to the material undergoing incineration. The type of compound containing such metals is technically of little importance in the context of the present invention so long as it forms a eutectic with the fluxing agent melt as is or yields a component, e.g. the elemental metal, for dissolution in the eutectic, at the temperature employed in the process, of the additional metal or metals to be added to the eutectic. For example, almost any calcium containing substance can be used as the fluxing agent in view of the fact that most calcium containing substances are converted into either lime or calcium hydroxide at the high temperatures of the combustion zone.
EXAMPLES
The experiments of the examples reported below were performed using a semi-industrial scale 82 kW (280,000 Btu/hr) horizontal tunnel combustor as shown in FIG. 1. This refractory-lined research combustor was designed to simulate the time/temperature and mixing characteristics of practical industrial liquid and gas waste incineration systems. Fuel, surrogate wastes, and combustion air were introduced into the burner section through an International Flame Research Foundation (IFRF) moveable-block variable air swirl burner. This burner, incorporates an interchangeable injector shown in FIGS. 2(a) and 2(b) positioned along its center axis. Swirling air passes through the annulus around the fuel injector promoting flame stability and attachment to the water-cooled quarl. For the research results presented here a high swirl (IFRF type 2) flame with internal recirculation (Swirl No.=1.48) was examined. Axial access ports permitted temperature measurement and injection of sorbents. Gaseous and aerosol samples were taken from a stack location 589.3 cm from the burner quarl. The temperature at this location was approximately 670 K (745° F.).
Metals were introduced as aqueous nitrate solutions through a special fuel/waste injector which incorporated a small air atomizing system down the center of a standard natural gas injector as shown in FIG. 2(b). The resulting droplet particle size distribution (PSD) was relatively narrow with a mean droplet size of approximately 50 μm diameter. Chlorine (Cl 2 ) was introduced, separately from the metal solutions, with the (secondary) combustion air. Powdered kaolinite, bauxite, or hydrated lime sorbents were introduced co-currently along the combustor centerline at a post flame location 76.2 cm from the burner quarl using a small screw feeder and air transport. Thus, the metal, chlorine, and sorbent were not mixed prior to their introduction into the combustor, and all interactions between these components were dependent upon normal mixing patterns.
Chemical composition samples and PSD measurements from the stack were taken using an Andersen Inc. eight stage, 28.3 L/min. (1 ft 3 /min.), atmospheric pressure cascade impactor and a TSI Inc. differential mobility particle sizer (DMPS). The impactor is designed to collect physical samples (available for subsequent gravimetric and/or chemical analysis) in nine (including the afterfilter) particle size ranges (0-0.4, 0.4-0.7, 0.7-1.1, 1.1-2.1, 2.1-3.3, 3.3-4.7, 4.7-S.8, 5.8-9.0, >9.0 μm). A preseparator was used to remove large sorbent particles. However, this material was included in the analysis of the >9.0 μm fraction. Impactor samples were examined for the metals of interest using inductively coupled plasma mass spectroscopy ICP/MS). Selected stages from replicate impactor samples were examined by scanning electron microscopy/x-ray dispersive spectroscopy (SEM/XDS), x-ray diffraction (XRD), and ion chromatography (IC) analyses. The DMPS classifies and counts particles within a working range of 0.01 to 1.0 μm diameter using principles of electrical mobility. The DMPS was configured to yield 27 channels evenly spaced (logarithmically) over this range.
The two-stage isokinetic aerosol sampling system was built based on the modified designs of Scotto. In order to minimize in-probe gas and aerosol kinetics, the sampling system dilutes and cools the aerosol sample using filtered nitrogen and air immediately after sampling. Calculated dilution ratios and sampling probe residence times are 15:1 and 0.2s, and 300:1 and 2.5s for the impactor and DMPS, respectively. Dilution ratios are measured directly and verified independently by the measurement of nitric oxide.
Metal/Sorbent Systems Investigated
Baseline experiments were performed injecting aqueous solutions of nickel [Ni(NO 3 ) 2 ], lead [Pb(NO 3 ) 2 ], and cadmium [Cd(NO 3 ) 2 ], with and without chlorine, into a 58.6 kW (200,000 Btu/hr) natural gas flame. Aqueous solutions containing 1.5% (by weight) metal were used. Solution flow rates were maintained so as to produce stack gas concentrations of approximately 100 ppm metal (by volume). Metal nitrate feed rates were 0.91, 1.73, and 1.19 g/min for the nickel, lead, and cadmium "wastes," respectively, and correspond to constant molar feed rates of 0.005 g-moles/min. Chlorine was added to maintain a 10:1 molar ratio of chlorine (as Cl) to metal, resulting in a chlorine stack concentration of approximately 1000 ppm (by volume). Excess air was maintained at 20%. No air preheat was employed. In contrast to previously reported research in which chlorine was introduced as an aqueous HCl solution through the same injector as the metal solution, chlorine in this set of experiments was introduced as Cl 2 gas with the combustion air. This procedural change, however, did not cause any noticeable change in the aerosol behavior and eliminated the severe injector corrosion problems previously encountered.
To complement the baseline experiments, kaolinite, bauxite, or hydrated lime sorbents were injected into the high temperature post flame. The measured temperature was approximate 1575 K (2375° F.). Sorbents were introduced at a rate of 3 g/min. As with the baseline experiments, sorbent testing was conducted with and without chlorine addition. Elemental analyses of the sorbents are as follows: kaolinite--19.0%, Si, 16.0% Al, 0.3% Fe, 1.0% Ti, <0.1% Ca; bauxite--3.0% Si, 35.1% Al, 1.1% Fe, 2.2% Ti, 0.1% Ca, <0.1% Mg; and hydrated lime--0.3% Si, 0.2% Al, 55.4% Ca, 0.1% Fe, 0.3% Mg. The kaolinite, bauxite, and hydrated lime sorbents used here had mass mean diameters and BET surface areas of 5.38, 10.79, and 2.24 μm, and 9.12, 0.69, and 22.8 m 2 /g, respectively. It should be noted that the trace quantities of nickel, lead, and cadmium introduced with the three sorbents were between 1000 and 10,000 times less than the quantities introduced as aqueous nitrates.
Nickel/Kaolinite/Chlorine System
FIG. 3A presents DMPS volume and FIG. 3B presents impactor nickel mass distributions for the nickel experiments. Without kaolinite addition (open symbols), the baseline data indicate little evidence of a notable submicron mode, but clear indication of a supermicron mode with mean particle diameter (d p ) of between 1 and 2 μm. Based on PSD measurements of the aqueous metal spray, this aerosol diameter is consistent with the mechanism of one residual nickel particle per initial spray droplet and is not consistent with any substantial nickel vaporization/nucleation or fragmentation. The low volatility of nickel and of NiO at these temperatures supports these conclusions.
With the addition of chlorine, the nickel behavior is quite different. Impactor data (Table 1) indicate that almost 80% of the nickel resides on particles less than 1.1 μm, and the DMPS data indicate a distinct submicron mode with mean d p between 0.05 and 0.1 μm. Moreover, this behavior is indicative of a mechanism of nickel vaporization followed by subsequent nucleation, condensation, and coagulation. This change is likely due to the dramatic increase in nickel volatility due to the addition of chlorine, although current thermodynamic equilibrium calculations were unable to predict the presence of nickel chloride vapor species at the temperatures encountered here. It should be noted that, while FIGS. 3A and 3B and the figures which follow present individual representative DMPS and impactor distributions, the quantitative data presented in Table 1 represent averages of replicate experiments.
Without chlorine, the addition of kaolinite indicates little change in the nickel PSD compared to the baseline data. With the exception of channels near 1.0 μm, where the sorbent PSD begins to dominate, the DMPS distributions are essentially identical. However, this is not surprising, as it can be shown that the times necessary for coagulation/agglomeration of nickel and kaolinite are exceedingly large and any notable interaction is unlikely unless the nickel is first vaporized.
With chlorine present, the nickel/kaolinite/chlorine data, FIG. 3A and Table 1 reveal substantial reductions of submicron volume (92%) and nickel mass fraction (81%) compared to the nickel/chlorine data. It seems likely that, once vaporized, the nickel is able to interact with and be adsorbed by the kaolinite, although the mechanism of this interaction remains unclear and does not appear to involve formation of a surface melt. SEM/XDS analyses of particulate samples collected on impactor stage 3 (1.1-2.1 μm) showed that high concentrations of chlorine did not coincide with high concentrations of nickel, which was not uniformly distributed on all sorbent particles. Therefore, the adsorbed compound was not a nickel chloride compound. SEM observations did not support the mechanism of coagulation of a nickel chloride fume with the sorbent. These results were supported by IC analysis of an afterfilter sample (0-0.4 μm), which indicated an overall nickel/chlorine molar ratio of 0.1. X-ray diffraction analyses failed to indicate the presence of a crystalline nickel compound in the sorbent, much of which melted at combustor temperatures, both with and without metal present and probably because of associated impurities. Indeed, the nickel seemed to be associated with melted particles in which silicon was dominant. These observations suggest that, at combustion temperatures, chlorine causes nickel to vaporize creating conditions which allow the nickel vapor to incorporate with the sorbent melt, yet forming a product that does not contain the chlorine.
Lead/Kaolinite/Chlorine System
In contrast to nickel, the lead baseline data of FIGS. 4A and 4B without chlorine, indicate the presence of a distinct submicron mode with a mean d p between 0.1 and 0.2 μm. This behavior is consistent with lead vaporization followed by subsequent aerosol formation and growth and is consistent with the known volatilities of lead and lead oxide. With chlorine added, this mode is shifted towards even smaller d p (between 0.03 and 0.1 μm) possibly indicating delayed nucleation and a less mature aerosol at the sampling location. In fact, the impactor data (Table 1) indicate that between 80 and 82% of the measured lead is associated with particles less than 1.1 μm for these two data sets.
With the addition of kaolinite, both the DMPS and impactor data indicate substantial reductions in the submicron aerosol volume and lead mass fraction (72 and 98%, respectively) compared to the baseline (without chlorine) distributions. Similar reductions are also evident comparing the distributions with chlorine (49 and 86%). Morphological observations indicated that much of the kaolinite melted, both with and without lead present. These results are consistent with those of Scotto et al, where high uptakes of lead on sorbent particles were associated with formation of melts on sorbent surfaces.
Cadmium/Kaolinite/Chlorine System
FIGS. 5A and 5B illustrate that the cadmium baseline and cadmium/chlorine data (without kaolinite) are similar to corresponding lead data presented above. Cadmium, CdO, and CdCl 2 vapor pressures are similar to those for lead, PbO, and PbCl 2 , all of which are notably high at the peak temperatures seen in the combustor. As with the lead system, the cadmium behavior is indicative of particle formation via a vaporization mechanism. The impactor data shows that 88 and 85% of the cadmium mass are associated with particles less than 1.1 μm for the cadmium baseline and cadmium/chlorine experiments, respectively.
FIGS. 5A and 5B also show that the addition of kaolinite causes substantial decreases in both the DMPS submicron volume concentration (61%) and the <1.1 μm impactor cadmium mass fraction (97%).
It is interesting to note that almost uniformly, for all metals and sorbents examined, quantitative reductions measured due to sorbent addition are much larger for the impactor data compared to the DMPS data. However, this can be explained based on the operation of the two instruments. The impactor with subsequent ICP/MS analysis yields specific metal concentrations (or mass fractions). The DMPS, although producing greater resolution, is less specific, counting and sizing all particles (for subsequent conversion to volume concentrations). If the addition of sorbent contributes, even minimally, to increases in the submicron aerosol volume, then this added material is counted against any toxic metal removal. This can be seen in each of the DMPS plots where sorbent-only distributions are included for comparison. The sorbents each contribute minimally to the distributions for particle sizes less than approximately 0.2 to 0.3 μm. However, the sorbent contribution becomes important for particle sizes greater than 0.5 μm, adding to the submicron mass. Therefore, even though the impactor data lack resolution, they are likely more indicative of the toxic metal behavior.
These results differ from those of Uberoi and Shadman in two important respects: (1) the amount of cadmium removed here (97%) in a time scale of seconds, is far higher than the 5% removed by kaolinite in their bench scale studies, and (2), the sorbent particles that removed cadmium here were melted, with no observable (by XRD) cadmium related crystalline structure, while in the bench scale studies they remained crystalline. The melt appeared to avoid limitations of pore blockage by reaction products, as identified by Uberoi and Shadman.
Cadmium/Bauxite/Chlorine System
With the addition of bauxite, the DMPS distributions (cadmium baseline and cadmium/bauxite) illustrate almost quantitative removal of particles <0.2 μm (distributions not shown). The impactor data (Table 1) indicate that 97% of the cadmium originally associated with particles <1.1 μm in diameter was removed from that particle size range through the addition of bauxite. These results are in agreement with those of Uberoi and Shadman which suggest bauxite to be an exceptional sorbent for use with cadmium. Furthermore, in both this combustor study and in the previous bench scale studies, the sorbent particles remained unmelted and crystalline. Therefore, sorbents that do not melt can also be effective in reactively scavenging toxic metals, provided that pore blockage is not a factor.
Cadmium/Hydrated Lime/Chlorine System (an embodiment of the present invention)
As with the two sorbents tested above, hydrated lime acts as an effective agent to scavenge cadmium which would otherwise contribute to the submicron aerosol fraction (distributions not shown). However, these results are in contrast to those of Uberoi and Shadman and one would not have expected reactive scavenging to occur. It is interesting to note that hydrated lime seems to be particularly effective even in the presence of chlorine. The 99% reductions in both submicron volume (DMPS) and cadmium submicron mass fraction (impactor) with chlorine present (Table 1), represent the greatest measured removals seen for any chlorinated system examined. In the absence of cadmium, the lime sorbent particles were crystalline, angular, and had not melted. With the addition of cadmium, the calcium rich sorbent particles melted. Calcium oxide, which is basic, is known to form eutectic melts with acidic metal oxides.
Mechanism and Conclusions
The impactor data were examined to determine the existence of any metal particle size dependence. Such dependencies sometimes yield information to identify pertinent mechanisms. The cadmium/lime system (with and without chlorine) indicates no particle size dependence. The lead/kaolinite and cadmium/kaolinite systems (with and without chlorine) exhibited weak d p dependencies with some enrichment in small particles, and this conclusion is consistent with the observation of Scotto et al. The cadmium/bauxite system (with and without chlorine) produced the most notable l/d p dependence, indicating a pore diffusion or external surface reaction rate controlled process.
The effect of chlorine is to significantly increase the submicron volume concentrations and submicron metal mass fractions, in the absence of sorbents, and to diminish sorbent effectiveness when they are present (Table 1). This work uncovered a new mechanism that allows the scavenging of refractory metals like nickel. According to this mechanism, nickel can be volatilized by chlorine and then scavenged by kaolinite to remove 80-90% of the metal, which could not be removed in the absence of chlorine. The chlorine, in effect, acts as a carrier of the metal to the sorbent melt surface, where the metal was adsorbed and the chlorine released.
The results of this investigation suggest that toxic metal capture by fluxing agents is more practical for industrial incinerators than was initially suggested by bench scale thermogravimetric reactor studies and that fluxing agents which form melts on their surfaces in combination with captured metals are particularly effective.
TABLE 1______________________________________Changes in submicron volume concentration and submicronmetal mass fraction with sorbent and chlorine addition.______________________________________ Volume conc. Volume conc. with chlorine % change d.sub.p < 1.0 μm d.sub.p < 1.0 μm due toDMPS (μm.sup.3 /cm.sup.3) (μm.sup.3 /cm.sup.3) chlorine______________________________________Ni baseline 4.02E+4 1.79E+5 +345.3Ni/kaolinite 5.21E+4 1.49E+4 -71.4% change due to +29.6 -91.7sorbentPb baseline 8.98E+4 1.08E+5 +20.3Pb/kaolinite 2.54E+4 5.46E+4 +115.0% change due to -71.7 -49.4sorbentCd baseline 4.79E+4 6.84E+5 +1328.0Cd/kaolinite 1.85E+4 2.14E+5 +1056.8% change due to -61.4 -68.7sorbentCd/bauxite 1.19E+4 1.66E+5 +1295.0% change due to -75.2 -75.7sorbentCd/hyd lime 1.66E+4 4.16E+3 -74.9% change due to -65.3 -99.4sorbent______________________________________ Metal mass Metal mass fraction with % change fraction chlorine due toImpactor d.sub.p < 1.1 μm d.sub.p < 1.1 μm chlorine______________________________________Ni baseline 0.471 0.791 +67.9Ni/kaolinite 0.155 0.150 -3.2% change due to -67.1 -81.0sorbentPb baseline 0.822 0.797 -3.0Pb/kaolinite 0.0170 0.111 +552.9% change due to -97.9 -86.1sorbentCd baseline 0.880 0.852 -3.2Cd/kaolinite 0.0296 0.445 +1403.4% change due to -96.6 -47.8sorbentCd/bauxite 0.0253 0.0652 +157.7% change due to -97.1 -92.3sorbentCd/hyd lime 0.0728 0.0075 -89.7% change due to -91.7 -99.1sorbent______________________________________
The invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, the scope of the invention being further indicated by the claims rather than limited by the foregoing description, and all changes which come within the meaning and range of the equivalents of the claims are therefore intended to be embraced therein. | A cloud or dispersion of a particulate flux is formed in a combustion zone for the purpose of capturing metallic vapor from the combustion gas by formation of a eutectic of the metal and the flux, as a melt on at least the surfaces of the dispersed flux particles. The flux particles are heated within the combustion zone to a temperature sufficient to form the eutectic melt. The preferred flux particles utilized in the invention include conventional metallurgical fluxes, e.g. calcium carbonate, sodium carbonate and magnesium carbonate. | 1 |
BACKGROUND OF THE INVENTION
This invention relates to the field of compact tractors and attachments thereto, and specifically to a new structure in scoops for attachment to and operation by such tractors. It is known to provide a scoop pivotable above a horizontal axis in a frame projecting forwardly or rearwardly from a tractor and variable in height with relation to the ground surface by a hitch actuated hydraulically or otherwise and forming a part of or an attachment to the tractor. One such arrangement is taught in Patnode U.S. Pat. No. 3,536,222, and includes a pin-in-hole arrangement for maintaining the scoop in a desired pivotal relationship to the supporting frame, the pin being withdrawable to permit the loaded scoop to tip and so dump its load. The connection between the tractor hitch and the scoop frame in this patent is partly rigid but also partly by means of chains, which permit an undesirable amount of freedom of movement, and hence of wear, in the coupling, and of vibration in the scoop attachment itself. The pin-in-hole arrangement is quite primitive and subject to rapid wear, not only in its intended use, but whenever the back of the scoop moves slightly with respect to its mounting frame under the forces acting during use of the device, and its proper engagement must usually be assisted manually.
SUMMARY OF THE INVENTION
I have discovered that it is advantageous to be able to use the scoop in a position in the frame 90 degrees different from the normal position, and I have devised a new arresting arrangement for limiting the pivotal movement of the scoop in its frame at this 90° position for one extreme position of the scoop, and for automatically but releasably holding the scoop in a second extreme position. My arrangement is such that a latching blade engages a finger to prevent pivotal movement of the scoop, but is isolated from any adverse effect due to the yielding or bulging of the metal under the forces of loading and carrying.
My invention is easily adaptable for cooperation with any of the well-known coupling arrangements or "hitches" for connecting a tractor to an accessory implement.
Various advantages and features of novelty which characterize my invention are pointed out with particularity in the claims annexed hereto and forming a part hereof. However, for a better understanding of the invention, its advantages, and objects attained by its use, reference should be had to the drawing which forms a further part hereof, and to the accompanying descriptive matter, in which there are illustrated and described certain preferred embodiments of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawing, FIG. 1 is a plan view of one embodiment of my invention;
FIG. 2 is a side view of the structure of FIG. 1 in a first position, shown in solid lines, and a second position, shown in broken lines;
FIG. 3 is a view like FIG. 2, showing the arrangement in a third position;
FIG. 4 is a perspective view of the scoop attachment of FIG. 1 to a larger scale;
FIG. 5 is a view similar to FIG. 2 showing a second embodiment of my invention;
FIG. 6 is a fragmentary perspective view, generally similar to FIG. 4, of the second embodiment;
FIG. 7 is a detailed showing of a latch and related elements making up part of my invention;
FIGS. 8 and 9 are views similar to FIGS. 2 and 1, respectively, showing a further embodiment of my invention;
FIGS. 10 and 11 are views similar to FIGS. 2 and 1 showing a still further embodiment of my invention; and
FIG. 12 is a fragmentary sectional view taken along the lines 12--12 of FIG. 11, parts being omitted for clarity.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
A compact tractor 10 is shown in FIGS. 1 and 2 to be connected to a scoop attachment 11 by a coupler 12 of a type commercially recognized as a Category "O" three-point hitch, which comprises a pair of lower arms 13 and 14 and an upper arm 15. Arms 13 and 14 are arranged for hydraulic operation between the solid line position and a second position indicated by the dotted line showing. Attachment 11 comprises a scoop 16 and a frame 17.
As shown in FIGS. 1-4, frame 17 comprises a main cross member 20 slightly longer than scoop 16, and having arms 21 and 22 extending in the same direction from its ends and bored coaxially. Member 20 may be a weldment or a Z-bar having a downward flange 23 and an upward flange 24. Secured to the top surface 25 of cross member 20 and the inner face of flange 24 are a pair of short rigid bars 26. Also secured to the surfaces of cross member 20 are a pair of rigid arms 31, 32 bent to jointly exhibit an inverted Y shape, reinforced by a gusset 33, and terminating in a pair of spaced ends 34, 35 bored as at 36 for connection with hitch arm 15. Arms 31, 32 and bars 26 are bored coaxially at 27 for connection with hitch arms 13 and 14.
Frame 17 also includes a latching member 37, which will be described more fully in connection with FIG. 7, and which is operated by an actuating line 40 passing through a hairpin guide 41.
Scoop 16 comprises a bottom 50, a pair of ends 51 and 52, and a back 53 which may be returned at 54 to act as a partial top for the scoop. The front edges of bottom 50 and ends 51 and 52 may be reinforced by a suitable member 55.
Ends 51, 52 are bored to pass a pair of pivot bolts 56, by which the scoop is pivoted in the coaxial bores in arms 21 and 22 using nuts 60.
A pair of fixed stop means 61 are provided in the form of blocks secured to the outer surfaces of ends 51 and 52 at their bottoms and near their centers: these blocks extend from the ends by more than the distances between the ends and arms 21 and 22, respectively. As shown in FIG. 3, these stop means engage the under edges of the arms of frame 17 when scoop 16 is positioned to a point where the bottom 50 is vertical. This prevents further pivotal movement of the scoop by reason of contact with the ground 63 when the vehicle moves in the direction indicated by arrow 64.
A stop finger 70 is secured to the outer surface of back 53, as best shown in FIG. 7. Finger 70 has a vertical stop face 71, a horizontal stop face 72, and a latching face 73. It is positioned on back 53 so that when scoop 16 is in the pivoted position shown in FIG. 2, surfaces 71 and 72 engage the face and top of flange 24, thus transferring thereto forces acting on back 53 due to use of the scoop.
Latching member 37 comprises a blade 74 pivoted on a bolt 75 extending between two mountings 76 carried on cross member 20. One edge 77 of blade 74 is urged toward engagement with flange 24 by a torsion spring 80, and this edge of the blade is provided with a notch 81 to engage surface 73 of finger 70. While ideally the surface of engagement between notch 81 and surface 73 should be a portion of circular cylinder axial about bolt 75, in practice it is found that a plane tangent to such a surface is sufficiently accurate for practical purposes. Line 40 is connected to blade 74 at 82.
My invention is equally useful when the scoop is to be used with tractors having the "sleeve" or "one point" type coupling hitch, as is shown in FIGS. 5 and 6.
For this use the scoop and its connections to and relation with the frame remain unchanged, but the frame itself is modified to accord with the hitch of the tractor. In FIG. 5, scoop 16 is shown as mounted in a frame 17a connected to the tractor 10a by a hitch 12a. Hitch 12a comprises a rigid structure 90 of metal including a pair of arms 91, 92 connected at first ends by a cross arm 93, and pivoted to the tractor at their other ends. A further stub arm 94 projects from the cross arm toward the tractor for connection to a lifting arm, not shown, to pivot the entire hitch about the pivots of arms 91, 92. The junction 95 between stub arm 94 and cross arm 93 is enlarged, reinforced, and bored to receive a linch pin 96.
Cross member 20a includes end arms as before for pivotally supporting the scoop, and for cooperating with stop means 61, and also includes latching member 37 for coacting with finger 70 on the scoop, and actuated by line 40a. A pair of metal plates 100 are secured to cross member 20a, as by welding, and are connected at the tops and braced at the sides by a reinforcing member 101 also secured to cross member 20a. An adjustment member 102 is shown to comprise a pair of side plates 103 welded to the base of a U-shaped member 104. The legs 105 of member 104 are spaced to receive member 90, and are bored at 106 to pass linch pin 96. Plates 100 are provided with pairs of holes, and plates 103 are provided with a plurality of pairs of holes, so that adjustment means 102 may be connected to plates 100 in any of a plurality of positions by use of bolts 107. In this form of coupling, a line guide 41a is also provided.
FIGS. 8 and 9 show my invention adapted for use with a still further tractor hitch in which lifting is manual rather than mechanical. A tractor 10b is provided with a hitch 12b wherein a manual lever 110 acts through a pair of levers 111 and turnbuckle arms 112 on a pair of lifting arms 113 loosely pivoted at first ends to the frame of the tractor. A further arm 114 of adjustable length is also pivoted at one end to the tractor frame. Scoop 16 and its relation with the frame 17b remain unchanged, but the frame itself is modified to accord with hitch 12b. In frame 17b, members 20b, 21b and 22b are as before. A plurality of vertical members 115, 116 and 117 are welded to frame member 20b and flange 24b at their lower ends, and to a cross member 120 configured at its ends to receive arms 113, which are retained by hairpins 121. Member 116 pivotally receives arm 114 at a bolt 122. A clevis 123 at the end of arm 114 enables longitudinal leveling of frame 17b. Latch member 37 is the same in this embodiment of the invention.
FIGS. 10 and 11 show my invention adapted for use with the hitch of FIGS. 8 and 9 in a way which has special advantages. In this embodiment, a pair of spaced structures 130 are secured to cross member 20c as by welding. Each structure comprises a first vertical bar 131 and a second vertical bar 132 having its top end 133 bent over and secured to the top of bar 131. Near their top bars 131 and 132 are bored coaxially at two places to pass a connection pin 134 for engagement with one of lifting arms 113. A cross bar 135 is secured to the bent ends of bars 132 by fasteners 136. An arm 137 is welded to project upwardly from the center of bar 135, and is connected to clevis 123 of arm 114 by a fastener 140. In other respects, the structure is as in FIGS. 8 and 9.
Operation
In operation, the scoop attachment is connected to the tractor by whichever hitch is provided therefor: if that of FIGS. 5 and 6 is used, an initial selection of bolt holes in plates 103 may be made to give the most favorable orientation of the scoop in the "down" position of the hitch. Scoop 16 is held in the position shown in solid lines in FIG. 2 by finger 70 and blade 74. The operator drives the tractor so that the scoop enters a pile of snow, dirt, or other material to be moved, and becomes filled with the material. Operation of the hitch now lifts the scoop - see the broken line position of FIG. 2 - and the material is transported to its desired new location. A pull on line 40 withdraws latching blade 74 from finger 70, allowing the scoop to dump its load. The hitch is lowered to pivot the scoop back to its initial position, whereupon latching blade 74 re-engages finger 70 so that another load of material may be picked up. It is to be particularly noted that any forces exerted by the loading procedure on the back of the scoop are not transmitted to latching blade 74, but are taken directly by flange 24 through surfaces 71 and 72 of finger 70.
If it is desired to perform a scraping operation, the scoop is not restored to its normal position, but it is positioned as shown in FIG. 3 so that the edges of bottom 50 and member 55 are in contact with the ground and the bottom of the scoop extends vertically. Now as the vehicle moves in the direction of the arrow in FIG. 3, pivotal movement of scoop 16 is prevented by stop means 61, and a satisfactory scraping operation results.
The advantage inherent in the improved modification of FIGS. 10-12 will now be described, referring particularly to FIG. 10. When arms 113 are connected to the upper holes in structures 130, handle 110 is positioned as shown in solid lines relative to the tractor operator, so that he can more conveniently apply the strength of his arm to actuate the handle in a pushing action supported by his body. It has been found that a load of 150 pounds can readily be lifted by the average operator from his normal position on the tractor seat in this mode of use of the device. There is, however, the disadvantage that the scoop cannot be lifted so far above the ground: where greater ground clearance is necessary the pins 135 should pass through the lower holes in structures 130 to provide maximum scoop travel from available handle travel. This is shown in broken lines in FIG. 10, and it will be apparent that the position of handle 110 is now so far back as to require less efficient application of the operator's strength to the operation in a sort of backhanded pulling action. For this mode of operation, it has been found that the operator's capability of ready lifting from his normal position in the tractor seat is in the neighborhood of only 100 pounds.
From the foregoing, it will be seen that I have invented an improvement in compact tractors with scraper attachments. My invention is adapted for use with tractors having any of the common hitches. It provides a pivoted scoop with limits to its pivotal movement in each direction, one of the limiting means including a readily releasable, automatically operable latching arrangement especially arranged for isolation from linear forces transmitted by the scoop during operation.
Numerous characteristics and advantages of my invention have been set forth in the foregoing description, together with details of the structure and function of the invention, and the novel features thereof are pointed out in the appended claims. The disclosure, however, is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts, within the principle of the invention, to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed. | An improved combination of compact tractor and scoop attachment, in which pivotal movement of the scoop in its frame in each direction is limited, and in one direction is retained by automatically operable, easily releasable means which is arranged to isolate the mechanism from forces transmitted through the scoop. As shown, the scoop frame is designed to receive numerous different coupling arrangements for various vehicle hitches. | 4 |
FIELD OF THE INVENTION
[0001] The general field of application of the invention is in power transmission devices, particularly variable displacement pump/motors for hybrid automotive use.
THE PRIOR ART
[0002] The growing utilization of automobiles greatly adds to the atmospheric presence of various pollutants including oxides of nitrogen and greenhouse gases such as carbon dioxide. Hybrid powertrains have been proposed in a quest for approaches which could significantly improve the efficiency of fuel utilization for automotive powertrains.
[0003] Hydraulic pump/motors are suited to many power transmission applications. An emerging application of these devices is in hybrid powertrains for automobiles. An example of such an application is disclosed in U.S. Pat. No. 5,495,912, “Hybrid Powertrain Vehicle” (Gray et al.). U.S. Pat. No. 5,495,912 discloses a drivetrain in which an internal combustion engine provides prime power to a hybrid vehicle while a subsystem consisting in part of one or more variable displacement hydraulic pump/motors serves to store engine power as pressurized fluid in a hydraulic accumulator at times of low road power demand, and to redeliver power from the accumulator at times of high road power demand.
[0004] In attempting to incorporate prior art pump/motors into such a system, one finds that such pump/motors are designed for specialized applications such as heavy equipment, industrial machinery, and aircraft control. The dominance of these applications has resulted in a predominance of designs that provide either a fixed displacement or, for those with variable displacements, relatively low peak efficiency limited to a relatively narrow band within the allowable range of speeds and displacements. Unfortunately, the duty cycle that is likely to be encountered in a hybrid automotive application would favor a design that can provide a high efficiency over a particularly broad range of variable displacement and speed. Moreover, if such devices were to be widely incorporated into automobiles, mass market pressures would call for higher quantity production and lower unit cost than is currently available for these devices. Also, automotive applications benefit greatly from reduced weight and volume. As a result, pump/motor designs of the prior art have frequently been found to be poorly suited to hybrid automotive power transmissions which are more demanding in terms of (1) maintaining high efficiency over a wide range of displacements and speeds, (2) adaptability to low cost, quantity production, and (3) for a specified power level, minimum weight and volume.
[0005] To fully understand the source of these limitations of prior art it is helpful to review the elements of variable displacement pump/motor design and in particular how their displacement is established.
[0006] Hydraulic pumps and hydraulic motors transmit power by conducting pressurized fluid between low pressure and high pressure reservoirs. Hydraulic pumps and motors of axial piston design are among the most efficient. For example, bent axis designs employ a rotating cylinder barrel containing a plurality of cylinders (typically seven to nine), which receive an assembly of reciprocating pistons (relative to the barrel). The pistons transfer power to and from an output/input shaft by their connection to a drive plate or drive block to which they are pivotably connected typically by ball and socket joints. In many designs the cylinder barrel and drive block are additionally connected by a universal joint.
[0007] The basic design of most axial piston pumps and motors potentially allows them to operate both as a fluid pump and as a motor, and so these devices are often referred to as pump/motors. When acting as a pump, mechanical power from an external source acts on a rotating input shaft which drives the piston/cylinder assembly in a way that creates reciprocatory motion of the pistons that in turn results in the pumping of fluid from a low pressure source to a high pressure source. When acting as a motor, fluid from the high pressure source flows in a reverse manner through the piston/cylinder assembly to the low pressure source, causing a reciprocatory motion of the pistons that delivers mechanical power to the rotating shaft which now acts as an output shaft.
[0008] The displacement of a hydraulic pump/motor (expressed in units such as cubic centimeters of fluid per revolution of the shaft) is established by the relative angle between the axis of the cylinder barrel which receives the pistons and the axis of the drive block on which the pistons act and are retained. Because the cylinder barrel and the drive block rotate together and are connected by the piston rods, the angle between them determines the stroke of the pistons and hence the displacement per revolution. In a fixed displacement design, for example, that of the type described in U.S. Pat. No. 4,579,043 (Rexroth), the angle is fixed and thus the displacement is fixed. In a variable displacement design, of which U.S. Pat. No. 5,488,894 describes one example, the angle can be varied during operation through an actuation means that varies the angle between the axis of the cylinder barrel and the axis of the drive block, thereby altering the displacement. In general, the larger the angle between the axes of the cylinder barrel and drive block, the longer the stroke of each piston per revolution, and hence the larger the total displacement per revolution. Conversely, zero displacement is approached when the axis of the cylinder barrel and the axis of the drive block approach a parallel alignment, which causes the stroke of the pistons to approach zero. Some designs not only accommodate such a zero displacement or “idling” position, but also allow the axis to proceed beyond this position in a condition referred to as “over center”, which results in a change in mode from motor to pump or pump to motor depending on whether the angle achieved is on the positive or negative side of the parallel condition. The machine described in U.S. Pat. No. 4,991,492 is one example of the “over center” type.
[0009] The prior art is dominated by two alternative methods for achieving a variable angle between the axes of the drive block and cylinder barrel. One method, commonly known as the swash plate design, varies the angle of a pivotable swash plate, which is a drive block that pivotably connects with the input/output shaft. The other, called the bent-axis design, instead pivots the cylinder barrel with respect to the drive block which remains at a fixed angle relative to the shaft. The bent-axis design houses the cylinder barrel in a cylinder body that pivots about a pivot point and provides fluid entry and exit through communication with a valve plate near the free end of the cylinder body. The bent-axis design is generally considered to provide better overall efficiency compared to other designs (for example, refer to the table of typical efficiencies provided in U.S. Pat. No. 4,271,725) and for this reason could be considered as better suited for automotive applications. Therefore, the bent-axis design is considered the most relevant prior art for the present invention.
[0010] The efficiency of the best conventional bent-axis designs peaks at values in excess of 90%, but only over a small portion of their allowable range of speed and displacement. At larger or smaller displacements and speeds, efficiency falls off dramatically. This narrow range of peak efficiency is a limitation encountered by other designs as well. Below about 50% of maximum displacement, mechanical losses and fluid compressibility losses become dominant sources of inefficiency. At larger displacements, the influence of the mechanical and compressibility losses are minimized by the longer piston stroke associated with larger displacements, but especially at higher speeds, flow losses become more significant.
[0011] With consideration of the basic design features of hydraulic pump/motors, the shortcomings of prior art designs in providing the above-mentioned desirable attributes for automotive applications will now be examined in turn.
[0012] (1) Large Angle for Maximum Displacement and Broad Range of High Efficiency
[0013] The design of prior art pump/motors imposes a number of obstacles that limit the achievable range of variable displacement angle. Typically, the maximum angle is limited by factors such as geometry or material properties that limit the bend angle, and by performance considerations that diminish efficiency or practicality. Due to these constraints, all variable displacement hydraulic pump/motors are limited to some maximum allowable angle. Prior art bent-axis designs rarely exceed a maximum angle of 30 degrees with about 25 degrees of variation, with the largest known maximum angle only about 40 degrees with 32 degrees of variation.
[0014] Another constraint is imposed by the need for the cylinder body (i.e., the barrel) to maintain communication with a fluid source throughout the allowable angle of pivot. This is most commonly achieved via a sliding connection between the barrel back plate having fluid ports and the fixed fluid ports in the pump/motor body. The finite size (to avoid excessive leakage) and fixed location of the fluid ports impose a limit on the maximum displacement angle because they must remain in communication with the moving barrel block plate at all of its positions without introducing undue fluid flow restrictions at the extremes.
[0015] Yet another constraint of most prior art designs stems from the fact that bent-axis units of the prior art typically pivot the cylinder body by use of a linear actuator acting on the outer arc of the angle through which the body can travel, that is, near the free end of the cylinder body. Here, to sweep the body through a large displacement angle requires a long actuation stroke owing to the longer chord of the arc of travel at this location. The need for a long actuation stroke prompts an increase in the dimensions of the control head which in turn leads to an undesirable increase in the overall dimensions of the machine. It is known in the prior art that actuation means may be relocated away from the outer arc toward the pivot point of the cylinder body, for example as described in U.S. Pat. No. 4,893,549 in which the device employs two counteracting servo pistons acting near the midpoint of the cylinder body. However, this innovation did not relocate actuation optimally close to the pivot point, and in fact was employed in a conventional back-plate design, rather than in a yoke design.
[0016] It is known in the prior art that fluid flow may alternatively be provided through passages within a yoke which houses the cylinder barrel and moves the barrel through its pivot angle. (Vickers bent axis pump motor AA606). This design can reduce the flow-related limit on pivot angle because it eliminates the necessity for fluid to be conducted through ports along a sliding interface with the back plate. Instead, fluid may enter through a point on the yoke, for example at its pivot point. Another example of this type of design may be seen in U.S. Pat. No. 4,991,492. In this example, a sliding contact with the outer case is retained for guidance and only one side of the yoke is used for fluid conduction. In other yoke-based designs, both sides of the yoke contain fluid passages, and the travel of the yoke is guided primarily by the retention of the yoke pins on which the yoke pivots.
[0017] But even in yoke-based designs, several additional constraints continue to act to limit the maximum angle. The use of a yoke does not prevent physical interference between parts such as the piston rods and the cylinder walls as the angle increases. Other geometric limits primarily involve the design of the cylinder barrel/drive block interface, in particular the design and arrangement (i.e., packaging) of a sufficiently strong universal drive joint mechanism, the connection rod retention mechanism that joins the piston rods to the drive block (usually spherical balls in the ends of the rods pivoting in sockets in the drive plate/block), and the relative diameters of the barrel cylinder centerline and the driveplate ball socket centerline. (For example, to achieve a larger displacement angle without encountering interference between the piston connecting rods and the bottom edges of their cylinders, the diameter of the piston ball socket centerline should be increased with respect to that of the cylinder bores.) Also concerns about possible barrel tipping at the valve plate interface with the higher piston side forces on the barrel, acting at greater distances from the barrel to valve plate interface (with the longer piston strokes), tended to discourage the pursuit of high angles.
[0018] (1a) Minimizing Flow and Compressibility Losses and Fluid Leakage
[0019] In normal operation as the cylinder barrel/drive block assembly rotates, the angle at which an individual piston rod will be inclined with respect to the walls of its cylinder will typically vary by 2 to 3 degrees, as the rod sweeps through a cone-shaped path with each revolution of the assembly. The magnitude of this variation or “wobble” is governed primarily by the angle of the barrel to the drive plate and the difference in the diameter of the centerline of the ball sockets on the drive block and the centerline of the cylinder bores in which the pistons reciprocate. Because as previously mentioned the diameter of the ball socket centerline should be increased relative to that of the cylinder bores in a large angle design, the pistons rods are likely to encounter wobble angles of 5 to 6 degrees or more.
[0020] Increased wobble angle leads to two issues associated with large displacements. First, a large wobble means that the pistons reciprocate at a larger angle with respect to the cylinder, transmitting higher side forces to the cylinder wall, potentially increasing wear, and also increasing the possibility of fluid loss by tipping. Second, a larger wobble angle may lead to increased leakage past the piston head depending on the method by which the piston head attains a seal with the cylinder walls. Leakage past reciprocating surfaces is typically addressed by the design of the piston head to include a secondary sealing means such as metallic or polymer rings. In designs that employ a pivoting connection between piston head and connecting rod, such rings are commonly employed but continue to allow some leakage especially as cylinder wear accumulates. In prior art designs that employ a rigid connection between piston head and connecting rod, any tilt in the piston leads directly to an equal tilt in the piston head. This complicates the problem of attaining a reliable seal due to the difference between the circular shape of the piston head and the elliptical shape of its interface with the cylinder wall when the piston head is tilted. In at least one commercial design attributed to VOAC, a number of circular metallic rings with variable eccentricity are employed to approximate such a seal, but this design is still prone to significant leakage even at relatively low angles.
[0021] Another impediment to maintaining good flow efficiency at a large displacement angle stems from the need to provide large fluid flow rates into and out of the cylinder barrel at large displacements and speeds. This is due to the increased stroke of the pistons at large displacement angles compared to the smaller stroke at small displacement angles. Previous designs have met with limited success in enlarging the fluid ports to accommodate high flow rates.
[0022] (1b) Minimizing Mechanical Losses
[0023] Friction is a dominant cause of mechanical loss, encountered at reciprocating surfaces such as the piston head/cylinder wall interface, interfaces such as the cylinder barrel/valve plate, the ball sockets by which the piston rods are retained on the drive block, bushings on which the yoke pivots, and bearings which react the forces imposed by the pistons on the drive plate which is supported by the input/output shaft. Of particular concern is friction at the ball sockets because reducing friction at this complex interface is also critical to increasing the life cycle of the device. Providing reliable lubrication at this interface would reduce losses significantly but has proven to be difficult to achieve.
[0024] (1c) Minimizing Tipping
[0025] The issue of tipping becomes problematic at large displacement angles because side forces exerted on the cylinder barrel by the reciprocating pistons tend to increase as the displacement angle increases, and their leverage increases as the angle causes them to act at greater distances from the barrel to valve plate interface. Since the cylinder barrel must be free to rotate within the yoke, there are only a limited number of options for providing resistance to side forces to ensure that the barrel remains properly seated. The primary method employed in the prior art is a hold-down device which rotatably clamps the barrel to the valve plate on which it rotates. Increased hold down force is therefore one option to prevent tipping, but this technique would increase the normal force acting on the interface between barrel and valve plate and thus lead to increased losses due to friction.
[0026] (2) Quantity Production
[0027] None of the dominant applications of hydraulic pump/motors strongly demand optimization of unit cost in quantity production. Because prior art pump/motor designs that are currently being manufactured are marketed to a relatively small market compared to the potential size of the automotive market, aggressive design optimization to reduce unit cost has not been a high priority because under these conditions such an effort may not be cost effective. As a result, there exists significant room for improvement in manufacturing and material costs for such devices.
[0028] (3) Minimum Weight and Volume
[0029] One trait of most currently produced designs is their rugged, heavyweight nature. In heavy equipment applications, ruggedness and weight are positive attributes due to the environment in which these devices are likely to be used. Stationary industrial applications do not require these traits as explicitly but, conversely, are not likely to suffer from them. As a result, reduction of weight does not appear to have been a priority in the dominant commercial designs. Likewise, minimization of package volume is not a critical concern in heavy equipment or industrial applications. Although aircraft control applications do call for lightweight and small volume, this application is the smallest fraction of existing usage and has not led to commercially viable lightweight and compact designs for other applications.
[0030] One reason for the large weight of prior art yoke-based designs is the need to resist distortive forces that act upon the yoke during normal operation as well as the large amount of force that must be resisted by bushings on which the yoke pivots (the origin of these forces will be discussed in a later section). These forces might be reduced if they could be balanced properly. The provision of a balancing force in reaction to varying pivot angles is known in the prior art. For example, U.S. Pat. No. 5,182,978 provides the drawing out of high pressure fluid to a hydrostatic radial or thrust bearing in response to changes in pivot angle.
[0031] In summary, the emergence of hybrid automotive applications of variable displacement hydraulic pump/motors provides a strong motivation to provide a bent-axis pump/motor design having a large maximum displacement angle and broad range of displacement variation, a broad band of speed and displacement at which high efficiency may be maintained, adaptability to quantity production at low cost, and minimum weight and volume.
SUMMARY OF THE INVENTION
[0032] The present invention achieves higher efficiencies over a broader range of displacement and speed than prior art due to the much higher displacement angles achieved by the incorporation of several novel design features. For a given displacement, the large angle of the present invention allows reduced piston diameter, reduced barrel diameter, reduced bearings size, reduced valve plate to barrel contact area, lower piston forces and lower ball to socket forces (all resulting in reduced friction and reduced cost).
[0033] Important to achieving high efficiency across small and large displacements is the discovery of effective strategies for (1a) minimizing flow and compressibility losses and fluid leakage, (1b) minimizing mechanical losses, and (1c) minimizing the chance of tipping. “Tipping” is a mode of fluid leakage that presents a higher risk at large angles, caused by momentary unseating of the cylinder barrel from the valve plate on which it normally rotates.
[0034] The present invention is based in part on a realization that a large displacement angle provides advantages for mechanical and hydraulic efficiency. A large displacement angle provides a longer stroke for each piston, which allows a smaller diameter piston and cylinder and a smaller piston notch circle, leading to lower fluid leakage losses and lower piston loads which in turn lead to less friction in the lower ball socket of each piston rod. A smaller piston notch circle also leads to lower valve plate leakage and lower friction torque on the valve plate. The invention therefore attains the maximum possible displacement angle by overcoming the shortcomings encountered in the prior art.
[0035] The present invention balances the forces on the bushings which support the yoke pins through use of slanted O-rings rather than by a variable throttle or control valve employed in the prior art.
[0036] (1) Large Angle for Maximum Displacement and Broad Range of High Efficiency
[0037] The present invention provides several approaches, which can be adopted alone or in combination, to achieve a larger displacement angle than was attainable in the prior art. First, a novel mechanism for displacement actuation is employed and is relocated to a point nearer the pivot point of the yoke, as compared to prior art, in order to improve the ability to reach large angles within a reasonable actuation stroke length. Second, the potential for interference among certain parts at large displacement angles is reduced by increasing the diameter of the circle on which the piston retention ball sockets lie relative to that of the circle on which the cylinder bores are arranged. Third, the retention plate is tapered and the piston connecting rods are tapered to further prevent interference of these parts. Finally, a new design for the universal joint increases its maximum bend angle without interference with other components.
[0038] Accordingly, the present invention provides a variable displacement hydraulic pump/motor including a yoke formed of a pair of shafts aligned to define a yoke pivot axis, a pair of arms having first ends located on the pivot axis and respectively fixed to the shafts. The arms extend perpendicular from the shafts to second ends where they connect with a valve plate extending therebetween. The valve plate presents a valve plate surface having intake and discharge apertures. A cylinder is mounted for rotation about a longitudinal axis with a plurality of piston cylinders formed therein in a circle centered on the longitudinal axis. Each piston cylinder is open at one end to receive the piston reciprocably mounted therein and has a cylinder opening at a second end of the cylinder barrel which presents a face mounted flush against the valve plate surface of the yoke, whereby the cylinder openings come into communication alternately with the intake and discharge apertures as the cylinder barrel rotates. A drive block is mounted on one end of an input/output shaft for rotation about a central axis of rotation which is inclined at an angle of inclination relative to the longitudinal axis of the cylinder barrel. Each of the piston cylinders has a piston mounted therein and connected to a first end of a piston rod with a second end of the piston rod pivotally connected to the drive block, the second ends forming a circular array within the drive block centered on its axis of rotation. The yoke can be pivoted to change the angle of inclination by means engaging at least one of the first ends of the arms. In a preferred embodiment, the drive block includes a body having sockets with socket openings at one surface and a retention plate, the retention plate having openings corresponding to and smaller than the socket openings, with balls fixed to the second ends of the piston rods retained within the sockets by the retention plate. The retention plate is thinned adjacent at least one of the plate openings so as to allow for a greater displacement angle, i.e., angle of inclination. Preferably, the circle defined by the piston cylinders in end view, centered on the longitudinal axis of the cylinder barrel, has a diameter which is smaller than the diameter of the circular array of sockets in the drive block.
[0039] (1a) Minimizing Flow and Compressibility Losses and Fluid Leakage
[0040] Leakage and other fluid related losses especially at high displacement angles can be minimized by any or all of several additional innovations. First, a novel single piece piston (the piston body does not pivot relative to the rod) with a deformable polymer seal ring is employed to reduce the potential for fluid losses past the piston that become a concern as the piston head pivot angle increases with increase in displacement angle. Second, a design referred to herein as “extreme porting” maximizes the size of the fluid ports on the cylinder barrel to accommodate the higher flow velocities associated with large displacement angles, partially enabled by minimizing the separation distance between cylinders. Finally, the pump/motor case is pressurized to a pressure equal to that of the low pressure accumulator, allowing any leakage that does occur to flow directly into the low pressure accumulator.
[0041] Accordingly, the present invention provides a variable displacement hydraulic pump/motor including a yoke formed of a pair of shafts aligned to define a yoke pivot axis and a pair of arms having first ends located on the pivot axis and respectively fixed to the shafts. The arms extend perpendicular from the shafts to second ends where they connect with a valve plate extending therebetween. The valve plate presents a valve plate surface having intake and discharge apertures. A cylinder is mounted for rotation about a longitudinal axis with a plurality of piston cylinders formed therein in a circle centered on the longitudinal axis. Each piston cylinder is open at one end to receive the piston reciprocably mounted therein and has a cylinder opening at a second end of the cylinder barrel which presents a face mounted flush against the valve plate surface of the yoke, whereby the cylinder openings come into communication alternately with the intake and discharge apertures as the cylinder barrel rotates. A drive block is mounted on one end of an input/output shaft for rotation about a central axis of rotation which is inclined at an angle of inclination relative to the longitudinal axis of the cylinder barrel. Each of the piston cylinders has a piston mounted therein and connected to a first end of a piston rod with a second end of the piston rod pivotally connected to the drive block, the second ends forming a circular array within the drive block centered on its axis of rotation. The yoke can be pivoted to change the angle of inclination by means engaging and rotating at least one of the first ends of the arms (located proximate the pivot axis).
[0042] In a preferred embodiment, the drive block includes a body having sockets with socket openings at one surface and a retention plate, the retention plate having openings corresponding to and smaller than the socket openings, with balls fixed to the second ends of the piston rods retained within the sockets by the retention plate. The retention plate is thinned adjacent at least one side of each of the plate openings so as to allow for a greater displacement angle, i.e., angle of inclination. Preferably, the circle defined by the piston cylinders, in end view centered on the longitudinal axis of the cylinder barrel, has a diameter which is smaller than the diameter of the circular array of sockets in the drive block.
[0043] Each of the cylinder openings is defined by radially inward and radially outward arcuate surfaces and generally radially extending surfaces joining the arcuate surfaces. The arcuate surfaces are spaced apart with the center of the spacing located radially outward of the central longitudinal axis of the cylinder bore with which the cylinder opening is in communication. In an end view cross-section, the radially outward arcuate surface extends circumferentially substantially beyond the cross-section of the associated cylinder bore.
[0044] As noted above, it is preferred that the structure further include the aforementioned single piece piston and that the pump motor have a hermetically sealed case to maintain lubricant therein at an elevated pressure.
[0045] (1b) Minimizing Mechanical Losses
[0046] Mechanical friction losses may be reduced by several of the features of the large angle design including (for a given displacement pump/motor) (1) reduced piston diameter, (2) reduced forces on the piston rod ball sockets, (3) reduced area of barrel to valve plate contact, and (4) reduced forces on the bearings of the input/output shaft.
[0047] In one preferred embodiment, mechanical efficiency, especially at high displacement angles, is improved by the use of novel lubrication means for the ball sockets on which the connecting rods pivot (e.g., higher than prior art case pressure). The loads acting on the yoke bushings and the bearing surface area of the yoke bushings are reduced by a novel means for balancing yoke forces that must otherwise be borne by the bushings, which has the effect of reducing the amount of friction encountered at the bushings.
[0048] Accordingly, in yet another aspect, the present invention provides a variable displacement hydraulic pump/motor including a yoke having a pair of axially aligned shafts which define a pivot axis for the yoke and a valve plate intermediate, connected to and axially offset relative to the shafts. The valve plate presents a valve plate surface having a pair of arc-shaped intake and discharge apertures. A radial port is formed in each of the shafts in communication with a fluid passage internal to the yoke and communicating with one of the arc-shaped apertures, whereby fluid flows through the radial ports perpendicularly to the pivot axis. As described above, the pump/motor further includes a cylinder barrel rotatable about a longitudinal axis and having a plurality of piston cylinders formed therein in a circle centered on its longitudinal axis. Each piston cylinder is open at one end of the cylinder barrel to receive a piston reciprocably mounted therein and opens at a second end of the cylinder barrel through a fluid port. The second end of the cylinder barrel is mounted flush against the valve plate surface for intake of fluid from one arc-shaped intake aperture to a fluid port in communication with one of the piston cylinders and discharge of fluid from another of the piston cylinders through another arc-shaped discharge aperture. The pump/motor further includes a drive block and pistons respectively mounted within the piston cylinders, as described above.
[0049] The pump/motor preferably further includes a pair of O-ring seals on each of the shafts and on opposing sides of a radial port. The O-ring seals of each pair are slanted in opposite directions at an angle of approximately 5-30 degrees to a plane perpendicular to the pivot axis. These O-ring seals are mounted so that they most closely approach each other at a point opposite the valve plate end of the yoke.
[0050] (1c) Minimizing Tipping
[0051] In the preferred embodiments, prevention of tipping at high displacement angles is achieved in part by use of a flared-base cylinder barrel with a narrow bushing surface on the outside edge that increases the “lever arm” of the base of the cylinder barrel in relation to the location of the side forces exerted by the pistons reciprocating in the barrel. The design and location of the barrel post bearing may also be optimized. Either or both of these approaches increase the resistance of the barrel to resultant forces that would cause tipping. Additionally, the fluid ports on the base of the flared cylinder barrel may be relocated slightly outward toward the outer circumference of the cylinders to increase the normal fluid reaction forces at the ports which oppose the piston side forces, further resolving the forces that lead to tipping.
[0052] Accordingly, in another aspect the present invention provides a yoke including a pair of shafts, aligned to define a yoke pivot axis, a pair of arms having first ends respectively fixed to said shafts and a valve plate, having intake and discharge apertures, connected to and extending between second ends of the arms. A cylinder barrel has one end flared to an end face larger than an end face (unflared) at the opposite end of the barrel. The cylinder barrel is mounted for rotation about a longitudinal axis and has a plurality of piston cylinders formed therein in a circle centered on the longitudinal axis. Each cylinder is open at the opposite end to receive a piston reciprocably mounted therein and has a fluid port at the one end, whereby the cylinder openings come into communication alternately with the intake and discharge apertures as the cylinder rotates. The one end face has a raised (axially extending) outer annular ridge on or adjacent its outer periphery and a raised (axially extending) inner annular grid surrounding and isolating each of the cylinder openings. The outer annular ridge and the inner annular grid, radially spaced from the outer annular ridge, seal against the valve plate. Of course, the raised sealing surfaces could be located on the valve plate with the barrel having a flat surface face to achieve an equivalent effect. A drive block and piston rods, as previously described, connect with the cylinder barrel.
[0053] (2) Quantity Production
[0054] Production cost in large quantities is improved by a number of features of the various preferred embodiments. The integration of several conventionally separate parts into the yoke is a primary feature of one preferred embodiment. Also, a simplified piston and rod ball design reduces the complexity of the pistons and rods, and may be adopted to further reduce manufacturing cost. Additionally, in other preferred embodiments, a new universal drive joint mechanism (as well as improvement of the basic tripode configuration) reduces manufacturing cost due to easier assembly and fewer parts. Finally, in yet another preferred embodiment, the pressurized case reduces manufacturing cost by eliminating the need for a separate charge pump and holding tank.
[0055] (3) Minimum Weight and Volume
[0056] A number of the innovations mentioned above lead to a reduction in weight and volume. However, the weight and volume of the device may be further reduced by any or all of several additional innovations. First, by introducing fluid flow into the yoke through radial ports rather than end ports, the rigidity of the yoke assembly may be reduced because the forces created by the radial flow into and out of the yoke are more easily resolved and so do not impose as great a distortive force on the yoke. As a result, less material need be used in construction of the yoke, leading to smaller volume and less weight. Second, the use of a hollow drive shaft instead of the conventional solid shaft further reduces the weight of the device. Third, a slanted O-ring design (discussed later) indirectly reduces weight and volume by reducing the necessary size and weight of the yoke bushings. Finally, the pressurized case reduces weight and volume by eliminating the need for a separate charge pump and holding tank.
[0057] The invention provides significant advantages over prior art pump/motors, particularly in their use in hybrid powertrains for automobiles, but also in many other applications. First, the invention allows the achievement of larger displacements angles and a larger range of variable displacements angles than are seen in any prior art designs, by removing many of the geometric and performance factors that limit bend angle in prior art designs. Second, the invention sustains a high efficiency over a wider range of displacements and speeds than previous designs, particularly by minimizing flow and compressibility losses, minimizing mechanical losses, and minimizing the chance of tipping. Third, the invention improves the ability to achieve quantity production at lower cost by incorporating several cost and complexity reducing concepts. Finally, the invention provides a bent-axis pump/motor having lower weight and smaller volume than that of prior art designs.
[0058] In preferred embodiments an improved tripod design provides a spherical bearing surface in place of separate guidance pins, reducing difficulty of assembly and manufacturing cost while allowing larger angles than previous designs. An alternative embodiment ball-disc flexible barrel drive shaft represents a further improvement in this regard. The outer portion of the retention plate is thinner than the inner portion in order to prevent interference with the barrel at large displacement angles, and the inner portion of the retention plate is more narrow then the outer portion in order to prevent interference with the piston connecting rods and ball joints at large displacement angles. Preferably, the porting arrangement provides greater flow area in the cylinder ports at large angles.
[0059] In other preferred embodiments high efficiency at large angles and across a wide range of angles and speeds is achieved by (1) the use of a single piece piston with rigidly connected head and deformable polymer ring which provides a more reliable sealing surface than previous designs at a low manufacturing cost and (2) the use of a pressurized case to improve lubrication of the ball and socket area and to allow leakage to flow directly into the low pressure accumulator.
[0060] Mechanical efficiency at all angles is also improved by the improved pressurized case lubrication of the ball sockets on the drive plate. Further, a reduced yoke pin bushing size may be adopted to reduce friction in a new yoke design which involves radial porting and slanted O-rings for improved force resolution.
[0061] Tipping may be further reduced by biasing of cylinder ports to the outer edge of the cylinder to improve force resolution and by adding to the barrel a flared-base with an outer edge anti-tipping bushing.
[0062] Further reductions in manufacturing cost in large quantity production can be achieved by the integration of the back plate, yoke pins, actuator pinion, and the single-piece cast construction of the yoke. Also, the drive shaft bearing race is preferably integrated directly into the drive shaft. Finally, the new tripode and ball-disc designs previously mentioned also serve to reduce cost.
[0063] Reduced weight and greater compactness are provided by the preferred radial arrangement of yoke fluid ports, in contrast to the end porting arrangement known in previous designs. The improved resolution of forces that results, reduces the potential for distortion of the yoke during operation, allowing for smaller and lighter construction. The use of a hollow drive shaft serves to further reduce weight of the pump/motor.
BRIEF DESCRIPTION OF THE DRAWINGS
[0064] [0064]FIG. 1 is a cross-sectional view of a first preferred embodiment of the hydraulic pump/motor of the invention;
[0065] [0065]FIG. 2 is a perspective view of the yoke of the embodiment of FIG. 1 showing the integrated valve plate, integrated yoke pins, and integrated actuator teeth which represent one example of means for yoke angle adjustment;
[0066] [0066]FIG. 3 is a cross-sectional view of the major components of a prior art bent axis hydraulic pump/motor, extended to an extreme angle to illustrate geometric limits encountered by such devices;
[0067] [0067]FIG. 4 is a sectional view of the drive mechanism of the first preferred embodiment of the present invention in a position of zero displacement showing the cylinder barrel, two representative pistons, a portion of the tripode (the specific universal drive joint mechanism), and the drive block;
[0068] [0068]FIG. 5 is a sectional view of the same components shown in FIG. 4 at maximum displacement;
[0069] [0069]FIG. 6 is a sectional view of a prior art piston;
[0070] [0070]FIG. 7 is a sectional view of a prior art piston at an angle within its associated cylinder as is commonly encountered during pump/motor operation;
[0071] [0071]FIG. 8 is a sectional view of another prior art piston, also at an angle within its associated cylinder common in operation;
[0072] [0072]FIG. 9 is a sectional view of a new single-piece piston in accordance with the present invention;
[0073] [0073]FIG. 10 is a sectional view of the piston of FIG. 9 shown at an angle within its associated cylinder;
[0074] [0074]FIG. 11 is a sectional view of a prior art tripode assembly;
[0075] [0075]FIG. 12 is a sectional view of a tripode assembly in accordance with the present invention;
[0076] [0076]FIG. 13 illustrates a prior art cylinder port arrangement;
[0077] [0077]FIG. 14 illustrates a cylinder port arrangement provided by a novel cylinder barrel in accordance with a preferred embodiment of the present invention;
[0078] [0078]FIG. 15 details the slanted O-ring system of the yoke pins of a preferred embodiment which provides hydrostatic balancing force to the yoke assembly;
[0079] [0079]FIG. 16 is a sectional view of an embodiment of the universal joint barrel drive-shaft, the “ball-disc” design in accordance with the present invention;
[0080] [0080]FIG. 17 is another sectional view of the universal-joint barrel drive shaft of FIG. 16;
[0081] [0081]FIG. 18 is an alternative embodiment of the new single-piece piston of FIGS. 9 and 10 , with a double ring configuration;
[0082] [0082]FIG. 19 is a sectional view showing an alternative yoke pin with radial porting;
[0083] [0083]FIG. 20 is a perspective view of the yoke with yoke pins as shown in FIG. 19;
[0084] [0084]FIG. 21 shows the ball-disc barrel drive-shaft of FIGS. 16 and 17 installed in a pump/motor of the present invention, inclined to 54 degrees;
[0085] [0085]FIG. 22 is an exploded view of a preferred universal joint;
[0086] [0086]FIG. 23 is a cross-sectional view of the universal joint of FIG. 22;
[0087] [0087]FIG. 24 is another cross-sectional view of the universal joint of FIG. 22;
[0088] [0088]FIG. 25 is a cross-sectional view of one end of a shaft of the universal joint of FIG. 22; and
[0089] [0089]FIG. 26 is a cross-sectional view illustrating details of the universal joint of FIG. 22.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0090] First, the basic operation of the invention shall be described by following the flow of fluid through a representative embodiment of the invention depicted in FIG. 1 operating as a motor.
[0091] Referring to FIG. 1, fluid at a high pressure enters at yoke radial port 1 and passes through fluid passage 2 within pivotable yoke 3 . Both fluid passages 2 and 6 are preferably of constant cross sectional area. The fluid then enters the valve plate port 4 at which point it begins to participate in a work producing cycle. In this cycle, high pressure fluid entering cylinder 10 pushes reciprocating piston 11 downward which exerts a force on driveshaft (input/output shaft) 14 causing it to rotate. About half of the additional pistons (not shown) will also be participating in various stages of their power stroke at any given time. Simultaneously, piston 13 is taking part in an expelling stroke (shared by the remaining pistons), traveling upward in cylinder 12 acting to expel the now low pressure fluid from cylinder 12 . This fluid exits through the opposite valve plate port 5 , through fluid passage 6 and through yoke radial port 7 proceeding to a low pressure fluid reservoir.
[0092] [0092]FIG. 2 provides a clearer view of the ports of the yoke. The semicircular shape of valve plate ports 4 and 5 and the radial position of yoke radial ports 1 and 7 can be seen clearly. Valve plate surface 18 a provides a smooth lubricated surface on which the cylinder barrel (not shown) rotates and receives and discharges fluid from and to the yoke passages. A hold down device (not shown) is anchored in retention hole 15 and rotatably clamps the cylinder barrel 19 (FIG. 1) to the valve plate surface 18 a.
[0093] Referring again to FIG. 1, yoke 3 can be pivoted about the axis of yoke pins 8 and 9 to achieve variable displacement. The mechanism by which this pivoting affects displacement is visible more clearly in FIGS. 4 and 5 which show cylinder barrel 19 housed rotatably within the cradle of yoke 3 viewed in line with pivot point 20 of yoke pins 8 and 9 . In FIG. 4, yoke 3 is in a zero displacement position in which it cradles the cylinder barrel 19 in a position parallel to the rotation axis 21 of drive block 22 . If the cylinder barrel 19 and drive block 22 were now to be rotated together, pistons 11 and 13 as well as the other pistons (not shown) would travel with them but remain stationary within their respective cylinders. In FIG. 5, yoke 3 has now moved to a maximum displacement position in which it now cradles cylinder barrel 19 at an acute angle to rotation axis 21 of drive block 22 . Now, if cylinder barrel 19 and drive block 22 were to be rotated about their respective axes, the pistons 11 and 13 as well as the other pistons (not shown) would be forced to reciprocate within their respective cylinders owing to the variation in distance between the surfaces of cylinder barrel 19 and drive block 22 as the assembly rotates.
[0094] (1) Large Angle for Maximum Displacement and Broad Range of High Efficiency
[0095] Some of the limits of the prior art encountered in achieving a large angle can be understood by referring to FIG. 3 which illustrates a prior art pump/motor (of the preferred yoke design) extended to an extreme angle. It can be seen that connecting rod 24 interferes with cylinder bottom edge 26 resulting in a zone of interference 27 . Similarly, there is interference between retention plate 28 and connecting rods 24 and 25 illustrated by zones of interference 29 and 30 . Additionally, zone of interference 31 shows interference of barrel connector 38 with drive block 33 . Finally, tripode guidance pins 34 and 35 are at an extreme angle and in this state may wander or fall out. Guidance pins 34 and 35 serve to guide and center the relative movement among drive block member 36 , central member 37 and cylinder barrel 32 .
[0096] The present invention eliminates the above and other problems described previously by means of several innovations. FIG. 5 shows the first embodiment of the invention extended to the same extreme angle as the prior art device of FIG. 3. The tapered design visible in connecting rods 16 and 17 eliminates interference between connecting rods and cylinder bottom edges (yet is still strong enough to prevent rod buckling), as illustrated by the lack of interference between connecting rod 16 and cylinder bottom edge 41 . The tapered design also eliminates interference between connecting rods and the retention plate as illustrated by the lack of interference between connecting rod 17 and the inner edge of retention plate 42 . Also, the tapering of the outer edge 43 of retention plate 42 prevents interference at the outer edge of the plate as indicated by the lack of interference with connecting rod 16 . Optionally, the tapering of outer edge 43 of retention plate 42 could extend to both sides of the ball socket interface to reduce the potential for interference even more on both sides of the ball joints. FIG. 4 shows clearly the optimum diameters of the centers of the ball socket ends of the rods 16 and 17 relative to the barrel 19 cylinders 10 and 12 , i.e., the diameter of a circle around which the piston cylinders are arranged in an end view of the barrel is smaller than the diameter of the circular array of ball sockets in retention plate 42 .
[0097] The problem posed by the tripode guidance pins is alleviated by an improved tripode design which eliminates guidance pins. The prior art tripode design is illustrated in FIG. 11 in contrast to that of the present invention shown in FIG. 12. In the improved design, guidance pin 46 (FIG. 11) has become guidance member 49 (FIG. 12) which is fixed to drive member 23 and slides along spherical surface 52 at the left end of central member 51 . Also, guidance pin 47 (FIG. 11) has become integrated with barrel connector member 50 (FIG. 12) and slides along spherical surface 53 of central member 51 . In this embodiment, the now integrated guidance pins no longer can misalign or fall out at extreme angles, yet they continue to provide effective guidance by sliding upon the spherical surfaces of the central member 51 .
[0098] A large displacement angle is further enabled by an improvement in the yoke pivot actuation means. Referring to FIG. 2, a yoke actuation pinion 56 having a gear sector 57 is located near the pivot axis of yoke pins 8 and 9 . Yoke pivot is achieved by the control of pinion 56 by a linear toothed rack within an actuator mechanism (not shown). The relocation r of the actuation mechanism to a point near the yoke pivot achieves a greater angle of pivot per unit length of actuation stroke than is possible by actuation mechanisms that act near the outer arc of the yoke pivot. In an alternate embodiment, actuation may be achieved by one or more similarly located hydraulic cylinder actuators in place of the illustrated gear sector 57 and rack.
[0099] (1a) Minimizing Flow and Compressibility Losses and Fluid Leakage
[0100] The problem of leakage associated with large piston wobble angles (for one piece piston/rod designs) is largely dependent on piston design. FIG. 6 illustrates one prior art piston design preferred for use in the present invention. In the prior art design shown in FIG. 6, piston 60 includes a piston head 61 with a number of metallic or polymer sealing rings 62 a and 62 b and a ball socket 63 which receives a rounded end 64 a (FIG. 7) of a piston rod 64 secured by a snap ring 65 . FIG. 7 depicts the piston 60 of FIG. 6 at an angle within a representative cylinder 67 . When the piston 60 is traveling upward within cylinder 67 under the influence of compressive force 66 , then a side force 68 is exerted on the inner wall of the cylinder 67 primarily at leading edge 69 of piston 60 . There is a tendency for leading edge 69 to generate friction when rubbing against the cylinder wall under influence of this side force 68 , leading to mechanical losses, increased wear, and leakage over time. In additional, the small ball end 64 a (small because of the need to fit within the piston 60 ) experiences extremely high loads (since the entire force acting on the piston 60 must be transmitted through this interface) and is prone to excessive wear and/or galling failure.
[0101] [0101]FIG. 8 shows another prior art piston 70 suitable for use in the present invention A rigidly attached piston head 71 has a plurality of metallic rings 72 that somewhat loosely encircle the piston head 71 . The round edge (spherical shape) of piston 70 serves to prevent binding and reduce wear on the cylinder wall 73 . Because the piston 70 is integral with the connecting rod 74 , when the connecting rod 74 is at an angle with respect to the cylinder wall 73 , piston 70 is also tilted within the cylinder 73 , meaning that the interface between the piston 70 and cylinder wall 73 becomes elliptical, making it more difficult to seal. The metallic rings 72 provide a degree of sealing because they are free to slide a limited distance off the centerline of the piston 70 , so as to maintain an approximate seal between the piston and the elliptical cylinder cross section. As a result, a relatively high leakage does occur, albeit less than would occur without the rings 72 .
[0102] [0102]FIG. 9 illustrates a new “single piece” piston 80 preferable design employed in the present invention, in preference to the prior art types of FIGS. 6, 7 and 8 . The term “single piece” as used herein refers to the rigid connection of the piston head to the connecting rod and not necessarily to a true single piece or “integral” construction. Rigidly attached piston head portion 81 a surmounts rod end 83 a of a tapered connecting rod 83 and a deformable polymer ring 82 . Piston head 81 consists of head portion 81 a and rod end 83 a and becomes spherical in shape, i.e., forms a spherical section, as it approaches ring 82 to provide low friction back-up support for ring 82 in reacting against piston side forces. Connecting rod 83 is united with ball joint 85 which is preferably a standard ball bearing. The polymer ring 82 has a spherical outer profile so as to continue providing a complete seal with the cylinder cross section even as the piston tilts through various angles. The polymer ring 82 is slightly deformable so as to insure a complete seal without the need for multiple rings and to compensate for any cylinder wear that may occur over time. The polymer ring 82 is approximately bisected by a plane 82 a passing through the spherical center of piston head 81 . By these means the new piston design provides improved sealing at the wide wobble angles characteristic of a large angle device. FIG. 10 shows the improved piston of FIG. 9 at maximum angle within the cylinder.
[0103] The need to accommodate high fluid flow rates at large displacements and high speeds is provided by the enlargement of the ports in the cylinder barrel. FIG. 13 shows a view of the port surface of a prior art cylinder barrel 32 where the cylinder barrel mates with the valve plate 39 (FIG. 3) of the yoke. Cylinder bores 40 receive and discharge fluid through ports 44 to valve plate 39 . The new design is depicted in FIG. 14. In order to accommodate larger fluid flows, ports 96 are increased in cross sectional area as much as possible, compared to ports 44 of FIG. 13, by increasing their radial dimension as well as their transverse dimension, with the ultimate limit to the transverse dimension being the minimum allowable thickness of web 48 .
[0104] (1b) Minimizing Mechanical Losses
[0105] Mechanical losses are minimized by reducing friction in the ball socket interface between the ball joints 85 and the drive block ball sockets 85 a and retention plate 42 (FIG. 5), in addition to the friction reductions features associated inherently with the large angle design. The pressurized case feature of the invention, up to 200 psi, provides increased lubrication to the ball and ball socket interfaces.
[0106] Mechanical losses attributable to pivoting of the yoke are also reduced by a reduction in the load necessary to be carried by the yoke bushings/bearings 8 a , 9 a , (FIG. 1). The innovation by which this is achieved is closely related to another innovation more directly related to reduction of weight and volume, and therefore it will be detailed more completely in that section. The nature of this innovation may be understood by referring to FIG. 2. In an assembled state, O-rings 101 , 102 , 105 and 106 provide sealing of fluid ports 1 and 7 and so the space between them is normally filled with a thin layer of pressurized fluid that exerts a force on the yoke pin joints and their bearing surface commensurate with the pressure of the fluid and the area of contact. It can be seen that these rings are slanted, in opposite directions, at an angle of up to 30° to a plane perpendicular to the axis of yoke pins (“shafts”) 8 and 9 , rather than concentric with the yoke pins, and as a result the width of the sealed juncture is not constant. Because of this, the resultant force exerted on the interface by the interstitial fluid varies with fluid pressure. The angle at which O-rings 101 , 102 , 105 and 106 are inclined is calculated to provide a hydrostatic counterbalancing force that matches the varying need for resolution of fluid reaction forces acting on the yoke to provide piston force, and the resultant radial forces that must be carried by the yoke bearing/bushings. This innovation reduces the maximum load experienced by the yoke bushings 8 a , 9 a (FIG. 1), thereby reducing the friction of the bushings by (a) reducing the necessary size and hence bearing area of the bushings and (b) reducing the amount of load held by and hence the force acting upon the bearing area of the bushings. Furthermore, the radial position of ports 1 and 7 leads to a reduction in weight of the yoke (as detailed later), which reduces the inertia of the yoke as it is pivoted to varying angles. This reduces the energy that must be expended toward the adjustment of displacement.
[0107] (1c) Minimizing Tipping
[0108] Prevention of tipping at high displacement angles is achieved in part by use of a flared-base cylinder barrel with an outer edge anti-tipping bushing. Referring to FIG. 5, it can be seen that cylinder barrel 19 has flared bottom edge 19 a which provides a wider base than the prior art cylinder barrel 32 of FIG. 3. The flared base bottom edge 19 a provides additional resistance to piston side forces that could cause tipping. For example, referring again to FIG. 5, when piston 13 travels upward in cylinder 12 under influence of compressive force 90 , compressive force 90 resolves into pumping force 92 and a side force 91 (not to scale) which acts on the cylinder barrel. If the resultant of all side forces exerted on all cylinders by all pistons at a given time is of sufficient distance from the base 19 a of cylinder barrel 19 and of sufficient magnitude, cylinder barrel 19 may become momentarily unseated from valve plate surface 18 a (FIG. 2), causing fluid to leak from this interface. The wider base provided by flared bottom edge 19 a increases the moment required to unseat cylinder barrel 19 by side forces and makes tipping less likely than in conventional designs. However, if the entire increased area of cylinder barrel base 19 a (FIGS. 4 and 5), as compared to the base of cylinder barrel 32 (FIGS. 3 and 13), were in contact with the yoke valve plate surface 18 a , lower sealing pressures around the fluid ports (“cylinder openings”) would result, and leakage across the larger area would exert greater separation forces. Accordingly, as shown in FIG. 14, the preferred cylinder barrel 19 has raised area 95 (“grid”) around the cylinder ports 96 to provide high pressure sealing and peripheral raised areas 97 on the outer edge 19 a of the barrel 19 , spaced radially outward from raised area 95 , to provide an anti-tipping contact bushing. Raised area or grid 95 is formed of radially inward arcuate surface 95 a and radially outward arcuate surface 95 b which define a centerline 95 d radially outward of the central, longitudinal axis 10 a of piston cylinder 10 , in contrast to the prior art of FIG. 13 wherein the centerline 44 d of each arcuate cylinder opening port 44 is slightly radially inward of central longitudinal axis 40 a of piston cylinder 40 . Also the section of radially outward arcuate surface 95 b (FIG. 14), which partially defines a cylinder opening port 96 for a single cylinder, extends circumferentially substantially beyond the cross-section of the associated cylinder 10 , again in contrast to the prior art of FIG. 13 wherein the cylinder opening port 44 , when completely uncovered, is wholly within the cross-section of the associated cylinder 40 . Separations or gaps 98 between raised peripheral areas 97 allow any leakage through sealing area 95 to escape to the case without exerting an additional separation force.
[0109] An additional change in the cylinder port design intended to further prevent tipping by improving the resolution of side forces, is shown in FIG. 14. Referring to FIG. 13, conventional cylinder barrel 32 having fluid ports 44 which conduct fluid into and out of cylinders 40 . In normal operation, fluid pressure within cylinder 40 acts on that area 45 remaining at the end of cylinder 40 not open at port 44 and creates a force that acts on the cylinder barrel 32 at the point of cylinder 40 that is the center of the remaining area 45 . This force acts to counteract some portion of any side force simultaneously being exerted by a piston on the cylinder 40 . In typical prior art designs as depicted in FIG. 13, cylinder ports 44 are not centered on the cylinder bores 40 but, rather, are located slightly inward of the center of the cylinder bores. FIG. 14 depicts a new port design in which ports 96 , as noted above, are located further out toward cylinder barrel outer edge 19 a , as compared to ports 44 in the prior art design of FIG. 13. As a result, the fluid forces created within cylinder 10 (and all others).are in a better position to counteract piston side forces being exerted on cylinder 10 (and all others) and hence cylinder barrel 19 is less prone to tipping. The resultant force within cylinder 10 would also be at the center of the remaining area 79 .
[0110] (2) Manufacture
[0111] Several innovations improve the manufacturing process and lower production costs as compared with the conventional pump/motor designs.
[0112] Referring to FIG. 1, an array of roller bearings 100 rotatably support drive shaft 14 . Conventionally, the bearing surface of drive shaft 14 would be provided by a race that is manufactured as a separate part and assembled to drive shaft 14 as part of the assembly process. In the invention, it can be seen that drive shaft 14 does not have a separate race but instead has a bearing surface 14 a machined directly into the shaft surface, eliminating the need to manufacture and assemble a separate race.
[0113] Similarly, the yoke has been designed to allow the integration of several parts that were previously manufactured separately and then assembled. Referring to FIG. 2, it can be seen that the yoke 3 is constructed in a single piece, preferably by a casting and machining process, rather than as multiple pieces as is more conventionally done. Yoke pins 8 and 9 are integrated with the yoke, being provided with a proper bearing surface by a machining process. The valve plate surface 18 a of back plate/valve plate 18 is also machined directly into the yoke surface to eliminate the need for a traditionally separate part. Similarly, actuator pinion gear 56 is also integrated with the yoke. Pinion teeth (“gear sector”) 57 are machined directly into the yoke and locally hardened.
[0114] The relatively large number of pistons that exist in a single pump/motor (as many as seven to nine or more) suggests that labor-intensive operations such as machining should be reduced for this part as much as possible. Referring again to FIG. 9, connecting rod ball joint 85 is fashioned from a standard ball bearing and attached to piston 80 preferably by friction welding or by a simple threaded connection, in contrast to the conventional practice of precision machining the ball as an integral part of the connecting rod piece.
[0115] The improved tripode design discussed previously and depicted in FIG. 12 further reduces the cost of manufacture by eliminating guidance pins 46 and 47 of FIG. 11, which significantly reduces the difficulty of assembly of the tripode.
[0116] A pressurized (hermetically sealed) case reduces manufacturing cost by eliminating the need for a separate charge pump and holding tank. Referring to FIG. 1, case 55 is maintained at a pressure equal to that of the low pressure accumulator (not shown) that receives low pressure fluid (typically up to 200 psi) after it has been used in a power producing cycle. In conventional designs, fluid that leaks into the case resides in a very low pressure reservoir (or holding tank) that is maintained near atmospheric pressure, and a separate charge pump is required to recharge this fluid to the low pressure accumulator. By providing a case pressure that is equal to that of the low pressure accumulator (on the order of 200 psi), the charge pump and holding tank are eliminated leading to further cost savings.
[0117] (3) Yoke Radial Ports
[0118] Referring again to FIG. 1, the flow of fluid into and out of yoke 3 is achieved through radial ports 1 and 7 through which fluid flows in and out perpendicularly to the pivot axis of the yoke, rather than parallel to it at its ends (i.e., axial) as known in the prior art. The advantages of a radial yoke port design over an end porting arrangement can be understood by considering the forces exerted on the yoke 3 and the cylinder barrel 19 during a typical cycle. In an end ported design, as high pressure fluid enters one end of the yoke, the fluid exerts a force on the end of the yoke commensurate with the pressure of the fluid and as a result tends to squeeze the yoke inward. To effectively counteract this distortive force, the yoke must be of very strong and heavy construction, adding to the overall weight of the device. In contrast, the fluid forces exerted on a yoke having radial ports will act in a direction perpendicular to the rotation axis of the yoke, which allows the fluid force to be opposed by bearings about which the yoke pivots, reducing the distortive phenomenon and reducing the need for as strong and heavy a construction for the yoke.
[0119] Furthermore, radial porting provides an opportunity to further balance the forces acting on the yoke so that a much smaller bushing with a lighter load rating may be used (although this can also be utilized with axial porting), additionally reducing the weight of the device. FIG. 15 details, the mechanism by which this balancing is accomplished. O-rings 101 and 102 (or other seals) seal radial port 1 in yoke pin 8 , creating a film of pressurized fluid in interstitial spaces. 103 and 104 . Because O-rings 101 and 102 are slanted at a specific angle, with the area of interstitial space 103 being appropriately greater than the area of the interstitial space 104 , there is a greater force acting on the yoke pin 8 from space 103 than space 104 . As the yoke 3 pivots through different displacement angles the direction of the net force follows the direction of the force from the yoke to be reacted at the pins, since the O-rings move with the yoke pin. Since the fluid existing in the space between the O-rings is always of the same pressure as the fluid entering or exiting the yoke radial ports 1 and 7 , the difference in area results in a resultant force being exerted on the yoke 3 which varies in accordance with the amount of force being experienced by the yoke. As a result, the magnitude of force that must be resisted by the bushing/bearings 8 a is smaller (depending on the relative areas of space 103 and space 104 ) and so the bushing can have a smaller load rating, allowing for use of a smaller and lighter bushing.
[0120] Referring to FIG. 1, it can be seen that driveshaft 14 is of hollow construction, reducing its weight compared to the conventional solid shaft design. As noted above, the pressurized case 55 allows for a further reduction in weight and volume by eliminating the need for a separate charge pump.
[0121] Many other modifications and embodiments of the present invention will become apparent to those skilled in the art from a reading of this specification.
[0122] For example, in other embodiments, the single-piece piston design of FIGS. 9 and 10 may be replaced by a prior art piston design such as that depicted in FIGS. 7 or 8 .
[0123] Further, while the embodiments described above illustrate the present invention in the context of a single-sided variable displacement pump/motor, which varies in angle from a zero displacement position (zero degrees) to a large positive displacement angle (such as 54 degrees) the invention can equally well be embodied in a over-center design, in which the bend angle may extend on both sides of a zero displacement position, for example, from positive 54 degrees to negative 54 degrees.
[0124] [0124]FIGS. 16 and 17 illustrate an alternate embodiment universal joint shaft of the tripode of FIG. 12. FIGS. 16 and 17 present two orthogonal section views of the flexible drive shaft, “ball-disc” design at its maximum bend angle, in this case an angle of about 54 degrees. Referring to FIG. 16, drive block ball head shaft 111 rotates within casing 112 which is inset within the end of the drive shaft (not shown). Drive block ball head shaft 111 articulately joins with cylinder barrel head shaft 118 by means of intervening parts 113 - 117 and 119 . The intervening parts forming the articulating joint are torque discs 113 and 114 , coupling halves 116 and 117 , and retaining pins 119 and 115 . In the bending mode depicted in FIG. 16, torque disc 114 has pivoted on retaining pin 119 as has torque disc 113 on retaining pin 115 . As cylinder block ball head shaft 118 rotates under power from the drive shaft (not shown), transferred first to drive block ball head shaft 111 , the torque disc 114 receives the bulk of the torque load and transmits it to coupling half 117 , which in turn transmits it to coupling half 116 , torque disc 113 , and cylinder block ball head shaft 118 . Referring to FIG. 17, it will be seen that this ball-disc joint design is universal in that it can accommodate bend angles in the orthogonal plane and in any arbitrary plane as well. Here, the bend capability has been provided by the pivot of cylinder block ball head shaft 118 within the semicircular recess 116 a of coupling half 116 , and the similar pivot of coupling half 117 about the semicircular ball head surface 117 a of drive block ball head shaft 111 . Each of coupling halves 116 and 117 has a cup-shaped socket at one end and a plurality of sectors similar to those shown as sectors 137 in the embodiment of FIGS. 22-26.
[0125] The advantages of the improved, flexible drive shaft design of FIGS. 16 and 17 include reduction in parts count, improved assemblability, improved velocity matching, and improved torque carrying capacity. In considering tripode and other flexible drive shaft designs of the prior art, these advantages become obvious. For example, with the tripode design as depicted in FIG. 11, typically 18 parts (consisting of 8 distinct parts) must be manufactured and assembled. Due to poor access to pin locations and to the connecting parts to which the joint assembly must mate, the 18 parts will not easily stay together as an assembly when outside of the pump and thus are difficult to place into a pump assembly. In contrast, the design of FIGS. 16 and 17 consists of a total of only 8 parts, of which 4 are distinct, and will stay together as two halves when assembled outside of the pump, and so greatly reduce the difficulty of assembly as well as the cost of manufacture.
[0126] The simplicity and ruggedness of the joint parts 111 - 119 of FIGS. 16-17 improve the torque load capacity over the prior art designs. In particular, the prior art embodied in the tripod shown in FIG. 11 relies on relatively small legs 37 a of the central member 37 to transmit torque from the central member 37 through the roller 86 and on to the drive block member 36 . In addition, torque transfer from roller 86 to drive block member 36 is performed by way of line contact, which increases stress and reduces durability. In contrast, all toque in the embodiment shown in FIGS. 16-17 is transmitted by way of area contact, which decreases stress and increases durability. Moreover, the simple compact design of this embodiment increases the torque-carrying capacity of all parts and results in a joint assembly having a smaller packaging envelope for the same torque capacity, allowing this joint to be fit into the relatively constrained space available in high-angle pump/motors.
[0127] In addition, unlike the prior art, the joint in FIGS. 16-17 contains coupling halves 116 and 177 which are allowed to slide axially in relation to each other. The sliding motion maintains strict symmetry of the joint, which allows perfect velocity matching between the drive shaft 14 and barrel 19 (FIG. 1). In contrast, the prior art, such as the tripod shown in FIG. 11, does not maintain symmetry and thus creates variations in velocity and clocking angle between barrel 32 and drive block 33 (FIG. 3).
[0128] [0128]FIGS. 22-26 show a presently preferred embodiment for a universal joint shaft connecting the barrel: of a pump/motor with a drive shaft. The universal joint shaft includes ball members 120 and 124 which are respectively received within a drive shaft 14 and the cylinder barrel 19 (FIG. 1). Ball 120 is integrally formed with a connection device such as threaded collar 121 which screws into a threaded opening in shaft 14 . A plug member 122 integral with ball 120 extends further within the shaft 14 . Ball member 124 has a collar 125 and a connection device such as threaded spindle 126 integral therewith. The threaded spindle 126 is threaded into a mating threaded, central bore within the cylinder barrel 19 . Balls 120 and 124 are respectively received within socket members 132 and 134 . The socket members each include a cup-shaped socket 133 , 135 at one side and a plurality of sectors 137 at its opposite side. The sectors 137 , in cross-section taken perpendicular to the axis of the universal joint, appear as sectors of an annulus, i.e., pie sectors. The sectors 137 of socket members 132 and 134 are pie-shaped and interlock to prevent the two socket members from moving laterally relative to each other. The balls 120 and 124 are respectively retained in sockets 133 and 135 by torque transfer pins 140 . Torque transfer pins 140 , in turn, pivot on and are held against lateral displacement from the balls and sockets by retention pins 142 . Optional retention rings 144 fit over sockets 133 and 135 with holes receiving opposing ends of the retention pins 142 to retain torque transfer pins 140 . Finally, a cage 146 fits over the interengaged sectors 137 of socket members 132 and 134 to allow axial movement while retaining alignment.
[0129] As seen in FIGS. 24-26, each ball has an hourglass-shaped opening 148 which receives a torque transfer pin 140 . Each ball 120 and 124 can pivot only through that angle α allowed by the hourglass-shaped opening 148 .
[0130] The advantages of this presently preferred embodiment of FIGS. 22-26 include those advantages mentioned for the embodiment exemplified in FIGS. 16 and 17. In addition, this presently preferred embodiment has improved ease of assembly, improved velocity matching and improved torque carrying capacity over the flexible drive shaft design of FIGS. 16 and 17.
[0131] The presently preferred embodiment utilizes torque transfer pins 140 in place of torque disks 113 and 114 . This embodiment strengthens the ball members 120 and 124 when compared with ball head shafts 111 and 118 , increasing the torque carrying capacity of the joint. In addition, the inclusion of the cage 146 in the presently preferred embodiment both improves the assembly of the universal joint shaft and constrains the joint in a way to improve velocity matching of the halves.
[0132] An alternative embodiment of the new single-piece piston of FIGS. 9 and 10 is shown in FIG. 18. This embodiment contains a piston top 220 and a sliding, sealing ring 222 a . Ring 222 a fits over a narrowed diameter post 224 of rod 223 which allows ring 222 a to slide to the appropriate position depending on the angle of rod 223 . Ring 222 b fits tightly around the locating post 224 of rod 223 . In this embodiment, ring 222 b can be optimized for load bearing capability and low friction and wear, while ring 222 a can be optimized for sealing.
[0133] [0133]FIGS. 19 and 20 show an alternative yoke pin with radial porting. FIG. 19 can be compared to FIG. 15, and FIG. 20 can be compared to FIG. 2. Yoke pin housing 238 provides an annular chamber 235 b supplying fluid to the complete circumference of yoke pin 236 to allow reduced flow pressure losses as fluid flows into port 235 a , while also allowing a shorter yoke pin 236 . FIG. 20 shows a clear view of the yoke pins 236 and 237 . Full circumference radial ports 231 a , 231 b , 236 a and 236 b allow high flow rates with low pressure losses. Multiple ribs 242 and multiple ribs 243 separate multiple ports 231 a and 231 b and multiple ports 236 a and 236 b . The shorter yoke pins 236 and 237 are evident. Other features seen in FIG. 19 are identical to those of FIG. 15 and identical reference numerals are employed. Likewise, other features shown in FIG. 20 are identical to those shown in FIG. 2 and identical reference numerals are employed.
[0134] [0134]FIG. 21 shows the ball-disk barrel drive-shaft of FIGS. 16 and 17 installed in a pump/motor of the present invention, inclined to 54 degrees. The features shown in FIG. 21 are numbered identical to the like features shown in FIG. 5, and are identical except for the substitution in FIG. 21 of the ball-disc barrel drive shaft of FIGS. 16 and 17 for the tripode barrel drive shaft of FIG. 5.
[0135] Referring to FIG. 9, another set of alternative embodiments would employ differing means of attachment of the ball bearing 85 to piston connecting rod 83 . This modification is based on recognition that a standard ball bearing possesses the necessary accuracy and tolerance of size and shape and therefore its use can obviate the need for the traditional costly and labor intensive precision machining process that must be employed to form the one-piece ball and piston connecting rod components of the prior art. While a threaded connection and a friction weld connection are specifically described in this disclosure, many alternate methods of connection will be obvious to those skilled in the art.
[0136] The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. | A variable displacement hydraulic/pump motor has a yoke with a pair of shafts aligned to define a yoke pivot axis and connected to a valve plate therebetween having intake and discharge apertures. A rotatable cylinder barrel has piston cylinders open at one end to receive a piston head and opening through fluid ports at another end, flush against the valve plate surface. A drive block is mounted on an input/output shaft for rotation about a central axis of rotation inclined at an angle relative to the longitudinal axis of the cylinder barrel which may be changed by a drive engaging the yoke at a point near its pivot axis. Loads on bushings supporting the yoke shafts are reduced by providing radially extending fluid ports in the shafts and in communication with the intake and discharge apertures of the valve plate. | 5 |
FIELD OF THE INVENTION
The present invention relates to a method for dyeing textile material with one or more fibre-reactive disperse dyestuffs in a supercritical or almost critical fluid, which textile material is selected from the group consisting of silk, wool and cellulose, combinations thereof and combinations of one or more thereof with synthetic fibres.
BACKGROUND OF THE INVENTION
A dyeing method of this type for dyeing wool and wool-containing fabrics is known from the article “Wolle färben ohne Wasser. Möglichkeiten und Grenzen überkritischer Fluide” in DWI Reports 122 (1999). In this article, it is stated that modification of supercritical carbon dioxide with water, although increasing the solubility of a conventional wool dyestuff in the supercritical fluid and considerably increasing the dyeing, causes damage to the fibres at dyeing temperatures of over 100° C. An increase in the temperature is desirable in order to raise the dyeing rate. Fibre-reactive disperse dyestuffs are not subject to the problem of a (too) low solubility. It is reported that the most important advantage of fibre-reactive disperse dyestuffs is that the washfastness and fastness to rubbing are good.
The dyeing of textile materials in a supercritical fluid per se is already known from DE-A1-39 06 724. In this known method according to DE-A1-39 06 724, a supercritical fluid which contains one or more dyestuffs is made to flow onto and through a textile substrate which is to be treated. The type of fluid is in this case selected as a function of the dyeing system, which system is determined by the type of dyestuff and the type of textile material. Optionally modified polar (dipolar) supercritical fluids or mixtures thereof are selected for polar dyeing systems, such as water-soluble reactive dyestuffs, acid dyestuffs and basic dyestuffs. One example of a modifying agent for changing the polarity of supercritical CO 2 is water, so that the dyestuff used dissolves better in the supercritical fluid. Nonpolar fluids are used for nonpolar dyeing systems, such as disperse dyestuff systems. For textile materials which contain both nonpolar and polar fibres and are therefore dyed using different types of dyestuffs, it is proposed in DE-A-39 06 724 for these materials to be dyed in a plurality of steps, each step using a system of dyestuff and supercritical fluid which is suitable for one type of fibre. CO 2 as nonpolar supercritical fluid gives good results for dyeing textile materials made from the synthetic fibres of polyester and acetate using disperse dyestuffs, as is also described DE-A1-43 32 219. It is assumed that carbon dioxide dissolves in hydrophobic fibres of the textile material, such as the abovementioned polyester and acetate fibres, with the result that these fibres swell (cf. EP-B1-0 222 207, in which this effect is described), so that the uptake of the disperse dyestuff is improved. However, the above technique cannot readily be used for hydrophilic fibres, such as wool, silk and cellulose (cotton, viscose) fibres, with the conventional water-soluble acid or reactive dyestuffs or with disperse dyestuffs. To make it possible to dye textile materials which contain wool, silk or cellulose, if desired in combination with synthetic fibres such as polyamide fibres or polyester fibres, for this purpose it is proposed in the abovementioned DE-A1-43 32 219 for the textile materials to be pretreated with a hydrophobic finishing agent (“Ausrüstmittel”) prior to the dyeing in supercritical CO 2 with a disperse dyestuff. This pretreatment can be carried out as a separate step by bringing the textile material Into contact with an aqueous solution of the finishing agent, if desired with heating, after which the pretreated textile material is thoroughly pressed and dried under conditions which are such that the hydrophobic finishing agent cures or crosslinks with the fibre. The pretreatment with the finishing agent may also be carried out directly in an autoclave in an atmosphere of supercritical CO 2 . However, the washfastness and fastness to rubbing of textile materials which have been pretreated in this way and dyed are lower than the fastnesses which are required and can be achieved with the conventional acid or reactive dyestuffs which have been dissolved in water. This shortcoming is described in DE-A1-44 22 707. Incidentally, it is pointed out here that acid and alkaline dyestuffs do not form a covalent bond, but rather a much weaker ionic bond. When textile which has been dyed with dyestuffs of this type is rinsed or washed, contamination is released on account of the poor fixation of the dyestuffs to the textile. According to the dyeing method which is described in this latter application, for dyeing cellulose-containing substrates with fibre-reactive disperse dyestuffs in supercritical CO 2 , the substrate is previously modified with compounds which contain amino groups, with the result that even and colourfast colours with good washfastness and fastness to rubbing are obtained. The fibre-reactive disperse dyestuffs used are dyestuffs which in addition to the fibre-reactive group do not contain any group which makes them soluble in water, and the fibre-reactive group itself is not or does not comprise a group which makes the dyestuff soluble in water. The term “fibre-reactive” in general refers to those molecule parts which can react and form a covalent bond with hydroxyl groups, for example of cellulose, or with amino and thiol groups, for example of wool and silk, of synthetic polymers, such as polyamides, and with amine-treated cellulose. The dyestuff therefore reacts with the fibres, so that a covalent bond is formed between the dyestuff and the fibre. A fibre-reactive disperse dyestuff of this type can be well fixed in cellulose and polyester materials on the basis of the chemical structure. However, the fixation of the dyestuff in polyester material is based on the penetration of the dyestuff into swollen polyester fibres, the dyestuff being mechanically “anchored” in the fibre when the swelling is eliminated at the end of the dyeing process. In the method described in the examples of DE-A1-44 22 707, a cotton-containing fabric is pretreated in accordance with a procedure which is known from EP-A1-0 546 476 and is then dried, after which the supercritical dyeing is carried out in an autoclave in which a dyestuff and a quantity of solid CO 2 are placed.
Currently, an increasing number of textile materials are being demanded and developed which are composed of different materials, for example purely of natural fibre materials, such as 80% cotton with the addition of 20% silk or wool, or combinations of natural fibre materials of this type with synthetic fibre materials, such as polyester and polyamide.
It has therefore been found that there is still a need for improvements and/or simplifications to the methods for dyeing textile materials in a supercritical fluid, in particular for combined textile materials which contain natural fibres, in particular based on cellulose (cotton, viscose).
It is an object of the present invention to provide a relatively simple and inexpensive method for dyeing a wide range of materials which contain at least one of the textile materials cellulose, wool or silk using one or more fibre-reactive disperse dyestuffs, resulting in colourfastnesses and washfastnesses which are comparable to or better than those achieved with reactive dyestuffs which are normally used for dyeing in water.
SUMMARY OF THE INVENTION
According to the invention, to this end the method of the type described in the introductory part is characterized in that the relative humidity of the fluid is in the range from 10-100% during dyeing.
The term supercritical fluid is understood as meaning a fluid in which the pressure and/or the temperature is/are above the critical pressure and/or critical temperature which is/are characteristic of the fluid in question. Examples of supercritical fluids which can possibly be used include, inter alia, CO 2 , N 2 O, the lower alkanes, such as ethane and propane, and mixtures thereof. In practice, the explosion limits and toxicity values also play an important role in the composition of the fluid.
The dyeing method according to the present invention is carried out under supercritical or almost critical conditions. This is contrary to WO 97/1743, wherein a continuous process for the application of textile treatment compositions to textile materials is disclosed. Therein the textile treatment composition such as a dipolar water soluble CI dye is dissolved in a supercritical fluid, however the application itself occurs under atmospheric conditions.
When carrying out the method according to the invention, it is ensured that a quantity of water is present and remains in the supercritical fluid, so that the relative humidity of the fluid lies between 10% and 100%, 100% representing the maximum molecular solubility of water in the supercritical fluid. If the relative humidity of the fluid is below 10%, the natural textile materials are too dry, and consequently the uptake of the dyestuff leaves something to be desired. It has even been found that dry CO 2 is capable of extracting some of the moisture which is naturally present in the textile materials, making the fibres less accessible to the dyestuff so that they are not dyed or are only slightly dyed. These natural, normal moisture contents for the various textile materials, based on the dry textile substrate, are approximately:
wool
14.5% by weight
cotton
11.0% by weight
viscose
13.5% by weight
silk
10.5% by weight
polyester
0.5% by weight
polyamide
4.0% by weight.
These moisture contents are based on the weight of the dry textile material in accordance with the following equation: ( % ) = m v - m d m d 100 % ,
where m v is the mass of the textile material in the moist or wet state and m d is the mass of the textile material in the dry state under normal climatic conditions (T=20° C.±2° C. and RH=65%±2%).
If dyeing is carried out with a relative humidity of the fluid which is over 100%, there is free water in the system, which may cause rings to be formed in/on the textile material. There may even be a (polar) liquid film on the textile material, which makes transfer of the nonpolar dyestuff difficult.
Maintaining the relative humidity of the fluid in the range from 10 to 100% during the dyeing ensures that the textile material remains sufficiently moist and therefore is and remains sufficiently accessible for the uptake of the dyestuff. Furthermore, it is assumed that cotton with water forms a stronger nucleophilic reagent for fixation of the dyestuff than dry cotton.
Good fixation of the dyestuff is necessary if good washfastness and fastness to rubbing are to be obtained. For this purpose, the fixation is to take place by means of a nucleophilic reaction between the reactive groups of the dyestuff, on the one hand, and the fibre, on the other hand, for which reaction moisture is required and which reaction leads to the dyestuff being covalently bonded to the fibres of the textile material.
The way in which the relative humidity of the fluid is set and maintained in the range from 10-100% during the method is not critical. The possibilities include injection of water into the supercritical fluid, pretreatment of the textile material with water and extraction of water with the aid, for example, of molecular sieves or a condenser. The relative humidity can be measured using a capacitance meter.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The relative gas humidity is advantageously in the range from 50-100%, more preferably 60%, in particular is approximately 75%. It has been found that a relative humidity of the fluid of approximately 75% is advantageous for dyeing cotton and silk with a view to the dyeing and fixation. With a view to dyeing wool and viscose, the relative humidity of the fluid is advantageously in the range from 60-100%, although with a view to fixation a relative humidity of approximately 75% is once again preferred (T=115° C. and p=260 bar).
Very good fixation for silk and wool is achieved with the aid of the method according to the invention, with 95-99% of the dyestuff being covalently bonded.
To obtain good fixation of the fibre-reactive disperse dyestuff which is used in the method according to the invention to cellulose-containing textile materials, it is advantageous to modify the reactive groups of the cellulose, as described, for example, in the abovementioned publication DE-A1-44 22 707, the substrate being modified prior to dyeing. A more general description of the modification of cotton is given by R. B. M. Holweg et al., “Reactive cotton”, 18th IFATCC Congress 1999, Copenhagen, Sep. 8-10, 1999, pp. 58-64. For this modification, so-called aminating agents are used, which contain amino groups which react with and are thus fixed to the cellulose fibres via a covalent bond. For use in CO 2 , it is common to use aminating agents with primary and/or secondary amino groups, with which the reactive groups of the fibre-reactive disperse dyestuff can react and form a covalent bond. One example of an agent of this type is an aliphatic polyamine, available from Clariant, which gives secondary amino groups to the cellulose fibres. These aminating agents may also be small molecules, as described in U.S. Pat. No. 1,779,970.
It will be understood that, strictly speaking, it is not necessary for the relative humidity of the fluid to be maintained in the range from 10-100% for synthetic fibres, such as polyester and polyamide fibres, if present in the textile material, since these materials, on account of supercritical fluid being dissolved in the synthetic fibres, already have a relatively great accessibility for the dyestuff. It has been found that, when dyeing polyester using the method according to the invention, no unacceptable negative results are obtained for either dyeing or fixation. It is thus also possible for textile materials which are composed of a combination of natural fibres and synthetic fibres to be dyed simultaneously and under the same conditions, in particular with the same fluid and the same dyestuff.
For cellulose, the desired relative humidity of the fluid is advantageously set by subjecting the textile material to a moistening step for premoistening the textile material with an aqueous moistening agent prior to the dyeing. The aqueous moistening agent may, for example, be water, to which, if desired, additives are added.
The moistening step may, for example, be carried out using the padding method (foulard), in which the textile material is passed through a bath of the aqueous moistening agent and then the material is squeezed until the desired moisture content is reached.
The aqueous moistening agent may contain at least one auxiliary. In particular, the moistening agent may contain one or more agents which promote the accessibility of the fibres of the textile materials for the dyestuff, such as the preferred melamine, urea or thiodiethylene glycol.
Another auxiliary which can be considered for use in the moistening agent is a reaction-accelerating auxiliary for accelerating the reaction between the reactive disperse dyestuff and the textile material. Examples of these auxiliaries include, inter alia, pyridine or ammonium salts. These reaction accelerators often contain tertiary and quaternary amino groups. The abovementioned aminating agents may also be added to the moistening agent. Then, the textile material is dyed in accordance with the method according to the invention.
If desired, an agent for promoting the solubility of the fibre-reactive disperse dyestuff, such as acetone or ethanol, may be added to the supercritical fluid.
The dyeing conditions are selected on the basis of the textile material to be dyed. The temperature is usually in the range from 20-220° C., preferably 90-150° C. The pressure which is applied during dyeing should be at least sufficiently high for the fluid to be in the supercritical or almost critical state at the prevailing temperature. The pressure is usually in the range from 5×10 6 -5×10 7 Pa (50-500 bar), more preferably 2×10 7 -3×10 7 Pa (200-300 bar). As non-limiting examples, it is possible to mention a temperature of approximately 140° C. and a pressure of approximately 2.5×10 7 Pa (250 bar) for dyeing cotton, while for wool a temperature of approximately 110° and a pressure of approximately 2.5×10 7 Pa (250 bar) are preferred.
In addition to the padding method mentioned above, the moistening can also be carried out prior to the actual dyeing process, in which case the textile material is already in a dyeing vessel of the dyeing device used.
The moisture content can also be set during the dyeing itself, for example by injection of water or steam into the circulating fluid, to which, if desired, the necessary additives are added.
In this context, it should be pointed out that adding water as modifying agent in order to increase the polarity of the supercritical fluid for polar dyeing systems is described in DE-A-39 06 724, with the result that the solubility of the polar dyestuffs in the supercritical fluid is increased. However, in the method according to the present application the fibre-reactive disperse dyeing systems are apolar. Free water is present in a system of this type. By contrast, in the present invention the water has the function of ensuring the accessibility of the fibres for the dissolved dyestuff, so that the fibres are able to take up the dyestuff.
A dyeing device which is suitable for use in the method according to the invention is known in the specialist field and is described, for example, in an article entitled “Experience with the Uhde CO 2 -dyeing plant on technical scale”, Melliand International (3), 1998.
The reactive disperse dyestuffs which can be used in the method according to the invention may be selected from the dyestuffs which are mentioned, for example, in DE-A1-44 22 707, DE-A-20 08 811, U.S. Pat. Nos. 3,974,160, 5,498,267, 4,969,951, CH-A-564 515 and Japanese patent publications JP-3-247 665, JP 92/059 347, JP 91/035 342, JP 91/032 585 and JP 91/032 587.
The present invention also relates to a device for dyeing textile material in a supercritical or almost critical fluid, comprising a pressure vessel for holding the textile material which is to be dyed and means for supplying the fluid to the pressure vessel, wherein the device is also provided with regulating means for regulating the relative humidity of the fluid. During use of the device according to the invention, the relative humidity of the fluid is regulated by measuring the actual relative humidity with suitable measuring means, for example with a capacitance meter, and, in the event of deviation from the desired value, either adding moisture or extracting moisture. For this purpose, the regulating means may comprise supply means for supplying moisture and/or means for extracting moisture to/from the supercritical fluid. The supply means may be directly connected to the pressure vessel but may also be connected to the supply means for the supercritical fluid. Supply means of this type comprise, for example, injection means for the injection of steam. A condenser and a bed of molecular sieve material are examples of means for extracting moisture from the supercritical fluid, which may be arranged, for example, in the circulation pipe network of the supercritical fluid.
The present application is explained below with reference to the following examples. In these examples, the dyeing efficiency (measure of the fixation) is determined by washing at 95° C. in accordance with the applicable ISO standard 105-C06, and determined with a boiling extraction with a mixture of water and acetone (volumetric ratio 4:1; t=0.5 h).
EXAMPLE 1 (D-III)
A rectangular piece of mercerized cotton weighing 21.5 g, with a natural moisture content of approx. 11% by weight, was premoistened with a mixture of 4.8% by weight aliphatic polyamine (Sandene) in water. Water was removed from the premoistened piece until it weighed 43.0 g. The piece was folded three times, so that it was divided into eight identical pieces, and was suspended at a height of approximately 25 cm in a cylindrical high-pressure vessel with a diameter of 12 cm and a height of 45 cm. A pulverulent orange reactive disperse dyestuff (available from Ciba Geigy) was placed in the bottom of the vessel, between two filter plates. The filter openings were smaller than the dimensions of the powder particles, so that the dyestuff was only able to flow through the filter openings and come into contact with the cloth in dissolved form. The vessel was sealed, after which CO 2 was pumped into the vessel with the aid of a feed pump. Once a pressure of 180 bar had been reached, a circulation pump was activated, so that the supercritical fluid circulated through the vessel at a flowrate of 110l/h. When a pressure of 210 bar was reached, the supply of CO 2 was stopped. The circulation of CO 2 was continued for two hours. The vessel was heated on the outside, with the result that the pressure rose to 284 bar and the temperature rose from 99° C. to 116° C. The mean pressure and temperature were 270 bar and 108° C. The mean relative humidity of the fluid was 58%, while the cotton had a moisture content of 8.8% by weight. The circulating CO 2 was first brought into contact with the dyestuff powder, so that the CO 2 was laden with dyestuff, and was then brought into contact with the suspended piece of cotton, to which the dyestuff was transferred. After two hours, the circulation pump was stopped and the CO 2 removed. The piece was very orange and evenly dyed. A section of the piece was then subjected to an extraction test using a mixture of acetone and water at the boiling point of this mixture. After the end of the extraction, 80% of the dyestuff was found still to be on the piece. Another section was subjected to a washing test at 95° C. Once it had finished, 94% of the dyestuff was found still to be present on the piece. The results of these tests indicate a very good fixation of the dyestuff.
When carrying out similar tests, in which cotton was wetted with water which contained an aliphatic polyamine as aminating agent and melamine as auxiliary, and was then dyed with the reactive disperse dyestuff at a mean relative humidity of the fluid of 70%, a mean pressure of 259 bar and a mean temperature of 112° C., a degree of fixation of 78% was achieved (test D-XI), but with a deeper dyeing than in Example 1.
An improvement to the degree of fixation was achieved when the cotton, prior to dyeing, was treated with the aliphatic polyamine in caustic soda solution at 50° C. and then, after the unfixed polyamine had been rinsed out, it is moistened with 1.3% by weight melamine in water in accordance with Example 2 below.
EXAMPLE 2 (D-X)
A rectangular piece of mercerized cotton weighing 21.5 g was premoistened with a mixture of 9.1% by weight aliphatic polyamine in NaOH at 50° C. The piece of cotton was then placed in a bath comprising 98.7% by weight water and 1.3% by weight melamine. Water was then removed from the piece of cotton which had been pretreated in this way, until the weight was 43.6 g. This cloth was suspended in the middle of the cylindrical vessel used in EXAMPLE 1, and the further procedure described in that example was repeated. The mean pressure and temperature were 267 bar and 113° C. The mean relative humidity of the fluid was 54%. The moisture content of the cotton was 7.9% by weight. The piece was very orange and evenly dyed. A section of the piece was then subjected to an extraction test using a mixture of acetone and water at the boiling point of this mixture. After the end of the extraction, 92% of the dyestuff was found still to be present on the piece. Another section was subjected to a washing test at 95° C. After the end of this test, 96% of the dyestuff was found still to be present on the piece. The results of these tests indicate very good fixation (mean 94%) of the dyestuff.
During this test, small pieces of viscose which had likewise been treated with the aliphatic polyamine, silk, wool and polyester were also dyed (cf. also EXAMPLE 3), and mean fixation values of 93, 94, 99 and 93%, respectively, were obtained.
When this test is repeated at a low relative gas humidity of 5% and T=110° C. and p=263 bar (test D-XIII), the pretreated cotton is only very slightly dyed, with a degree of fixation of 36%. The piece also processed at the same time, of silk is scarcely dyed at all, the piece of wool is very slightly dyed with a degree of fixation of 81% and the polyester is well dyed with a degree of fixation of 91%.
EXAMPLE 3 (D-I)
A rectangular piece of dry, mercerized cotton weighing 24.6 g was moistened with a mixture of 98.8% by weight water and 1.2% by weight melamine. In addition, a rectangular piece of silk weighing 0.4 g, a piece of knitted wool weighing 0.3 g and a piece of polyester weighing 0.3 g were treated with the above mixture of water and melamine. These three pieces were placed in the pretreated piece of cotton. After removal of water, the weight of the piece of cotton was 47.3 g. Then, the complete set was dyed in the same way as described in EXAMPLE 1. The mean pressure was 272 bar. The mean temperature was 112° C. The mean relative humidity of the fluid was 74%, while the cotton had a moisture percentage of 12.3% by weight. After the dyeing process had finished, sections of the pieces of textile were extracted using a mixture of acetone and water at the boiling point of this mixture. In this case, it was found that, after extraction, 95% remained on the silk, 97% remained on the wool, 97% remained on the polyester and 34% remained on the cotton. | In a method for dyeing textile material with one or more fiber-reactive disperse dyestuffs in a supercritical or almost critical fluid, such as CO 2 , which textile material is selected from the group consisting of silk, wool and cellulose, combinations thereof and combinations of one or more thereof with synthetic fibers, such as polyester and/or polyamide, the relative humidity of the fluid is in the range from 10-100% during dyeing. Textile materials which have been dyed with the aid of this method have properties which are at least equal to those of textile materials of the same type which have been dyed in the traditional manner using water-soluble dyestuffs. A device for carrying out the dyeing method is also disclosed. | 8 |
BACKGROUND OF THE INVENTION
1. Introduction
This invention relates to an improved method of treating the surface of an organic polymer substrate prior to electroless deposition of a metal coating. The method is easy to use, represents a reduction in the number of pretreatment steps necessary prior to electroless deposition of a metal onto the substrate and provides improved adhesion between the substrate and metal deposit.
2. Discussion of Prior Art
Even though significant progress has been made in the art of plating metals on plastics, the adhesion between the coating and the plastic still leaves much to be desired. Poor adhesion between the plastic and the metal plate allows differential dimensional changes with temperature which may result in warping, blistering, and cracking of the metallized product. Consequently, strong adhesion between a plastic substrate and the plated metallic layer is essential for any application in which the product is subjected to significant temperature fluctuations.
Numerous methods are proposed in the prior art for depositing a metal coating over plastic. The method most commonly used involves steps including surface converting a plastic part with an oxidant such as a solution of alkaline permanganate or sulfuric acid containing a source of hexavalent chromium ions, deposition of a conductive, adherent metallic film by chemical reduction followed by electrodeposition of an intermediate layer, frequently copper, and finally a layer of a desired outer metal coating such as chromium, nickel, gold, solder, silver or zinc. Only moderate bond strength between a plastic substrate and metal coating is obtained by this method. Also relatively high temperatures are required for the surface converting step and careful control of the chromium ion concentration is necessary.
Plastics show a relatively poor affinity for metal and to promote a stronger bond between a plastic substrate and a metallic coating the prior art has frequently resorted to roughening the plastic surface to provide locking or keying between the surface and its coating. The surface of a molded plastic article normally is glossy and quite hydrophobic. Consequently, this surface is unreceptive to aqueous solutions used in electroless metal deposition. Since the sensitizing and activating solutions will not wet the surface, the metal ions are not adsorbed onto the surface and deposition of the metal cannot proceed.
Rendering the surface of the substrate hydrophilic by roughening has been common practice in plating plastic materials. Initially, this surface roughening was accomplished by some form of mechanical deglazing, such as scrubbing with an abrasive slurry, wet tumbling, dry rolling or abrasive (sand) blasting. These procedures generally lead to a composite having an adequate bond between substrate and coating, but due to relatively large visible irregularities on the plastic surface formed during the roughening operation, a thick metal coating must be applied to avoid surface defects and obtain a coating having a smooth, highly polished appearance. Mechanical deglazing of the surface has been found to be fairly effective, but is extremely costly in that many parts have to be finished by hand. Another disadvantage to mechanical etching is that it is hard to control and many problems are encountered when the surface abrasion is carried too far. Methods of mechanical roughening are not applicable to three-dimensional products or more particularly, printed circuit boards having through-holes. In any event, adhesion values above one pound per inch are only rarely obtainable.
Roughening has also been accomplished chemically using an acidic etch solution or a solvent for dissolving a portion of the plastic surface. Chemical deglazing or etching techniques usually require use of strong, acidic solutions such as sulfuric acid and chromate salts. The latter treatment was found to have the effect of activating bonding sites for subsequent electroless metal deposition. Chemical etching by an acid chromate oxidizing solution was then found to be more effective when the surface was pretreated with a strong caustic, such as sodium hydroxide, combined with immersion in a reducing solution containing hydrochloric acid after the etching.
Further improvements of bond adhesion included using a pretreatment emulsion as described in U.S. Pat. No. 3,574,070. The emulsion consisted of a non-solvent for the plastic and a solvent for the plastic which were emulsifiable.
U.S. Pat. No. 4,594,311 describes a process for restoring hydrophobicity to the exposed surface of an adhesion promoted resinous surface of a base material after a catalytic resistless image has been imposed thereon. The process involves exposure of the treated resinous surface to a solvent or solvent vapors in order to restore hydrophobicity to the surface.
Pretreatment of an ABS polymer substrate prior to electroless deposition of metal is described in a 1969 U.S. Pat. No. 3,445,350. The method relates to specific solvents which may be used with the specific ABS resins to achieve improved adhesion.
Further studies in the area of adhesion promotion of ABS resins, including platable grades, showed that even though bond strength was improved, organic pre-etching has been observed to have an adverse effect on surface appearance. It was observed that when an ABS resin is organically pre-etched there is incomplete drainage of the pre-etch solution from the articles when they are withdrawn from the tank. Such problems showed themselves as defects in the article surface after electroless plating.
Another attempt at improvement was made and disclosed in U.S. Pat. No. 3,689,303. This process for pretreatment added an additional step of contacting an ABS resin article with an oxidizing agent prior to the organic pre-etch step. The method involves an 8-10 step process for pretreating an ABS resinous substrate prior to electroless deposition of metal.
Another patent, U.S. Pat. No. 4,552,626 teaches a combined pretreatment step of deglazing and removal of filler by use of an acid bath for polyamides. This step is preferred over the use of an organic solvent bath to deglaze the substrate, which may result in gelling of the resin if the solvent is not dilute.
U.S. Pat. No. 3,963,590 describes a process for electroplating polyoxymethylene (polyacetal). The pretreatment process involves treatment with quinoline or gamma-butyrolactone prior to acid etching.
While such methods as described above increase adhesion, they are often not entirely satisfactory for several reasons. Such techniques are not always transferable to all substrates and particularly not to all grades of engineering thermoplastic substrates. Use of such techniques may result in degradation of the molecules forming the surface of the substrate, and may decrease both tensile and impact strength of the substrate due to swelling and cracking of the entire substrate material. Several of the prior art solvents used for organic pre-etching are also not suitable because they are known to remove significant amounts of the resin or resin filler, thus having a direct effect on the integrity of line and space dimensions of 15 the substrate during further processing.
U.S. Pat. No. 4,775,449 provides a process for improving adhesion of metal to a polyimide surface without physical modification or degradation of the surface structure. The process involves pretreatment of the polyimide surface with an adhesion promoting compound containing a nitrogen-oxygen moiety prior to plating.
An object of this invention is to provide an improved process for promoting the adhesion of metal to various engineering thermoplastic substrates without physical modification or degradation of the surface structure. The cohesive integrity of the surface of the substrate is maintained throughout subsequent processing steps. The method provides a means for increasing the adhesion of metallic traces to the surface while maintaining the ability of the surface to be patterned by various techniques.
SUMMARY OF THE INVENTION
The invention to be disclosed describes a pretreatment conditioner for use with various engineering thermoplastic resins prior to electroless deposition of metal. The process constitutes an improvement over the prior art since a significantly higher degree of adhesion can be achieved using a solvent system with little degradation or deformation of the substrate. More specifically, the invention relates to use of a specific conditioner for polyetherimide thermoplastics prior to oxidizing etchants, which pre-conditions the resin, greatly influencing the way that the etchant attacks the surface. This pre-treatment allows the etch to create a maze of submicroscopic cavities or pores on the surface, which can act as interlocking sites for the autocatalytically deposited metal film. The nature of this surface plays a significant role in establishing adhesion without unduly weakening or adversely affecting the physical characteristics of the resin. The specific conditioner, which is a lactone, when employed under various process parameters, consistently produces adhesion values in the range of 8-16 lbs./linear inch depending on the grade of the substrate.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The substrate of the present invention may be in a variety of shapes and sizes. The substrate may be produced by various methods including extruding, injection molding, machining or other methods known to the art. The polyimide material useful with this invention may be any of a group of high polymers which have an imide group (--CONHCO--) in the polymer chain. Polyimides are manufactured through a variety of methods with those formed by reacting bis-phenol A dianhydrides with phenylene diamine producing a group referred to as polyetherimides. The preferred polyimides for the present invention are those commonly referred to as "polyetherimides" for example, the General Electric Ultem brand plastic. The polyimides may contain various amounts of fillers or reinforcing agents which are well known in the art. These fillers may include glass, silica, mica, mineral glass and others. The amount of fillers present helps to further classify the polyimide resins into various grades. The process is also applicable to resins which may contain other components including antistatic agents, pigments, plasticizers, antioxidants and other similar functional additives.
The conditioner used in the pretreatment step prior to etching is a lactone. The use of a lactone as a conditioner represents an improvement over prior art since it provides greater potential for through-put of articles, has less tendency to be hydroscopic, and is more easily waste-treatable than other conventional solvents used. The preferred lactone for use with polyimide substrates is gamma-butyrolactone. This lactone was specifically selected because it is less aggressive with the recommended substrates and for the selective chemistry between the lactone and the substrate. It promotes adhesion without unduly weakening or adversely affecting the physical characteristics of the resin. Gamma-butyrolactone softens the surface of the resin enough to allow the subsequent etchant to create a microporous surface suitable for initial metallization with minimal degradation of the substrate which insures cohesive integrity of the substrate during functional testing. The degree of softening and depth of chemical attack is controlled for the selected substrate in order to provide optimal adhesion values in the range of 8-16 lbs./linear inch. Control of the amount of softening and the depth of penetration is achieved by selecting the time, temperature and concentration of the lactone. The concentration of the lactone in the conditioner depends on the particular resinous substrate used, and is typically in the range of 50-100%, but is preferably used in a more concentrated state (85-100%). The temperature of the solution during immersion of the substrate may range from about 24° F. to about 65° F. The time of immersion again depends on the particular substrate and may range from 1-10 minutes, but is preferably 1-5 minutes.
An important step in the operation of the invention is the use of a water rinse immediately after conditioning. The temperature of the water may be chilled or room temperature but is preferably in the range of 38° F.-100° F. This step insures that the pores of the substrate remain open while effectively rinsing the conditioner from the substrate. This allows the next step of oxidative etching to create the desired micro-porous surface.
Subsequent steps prior to electroless metal deposition may include chromic acid or permanganate etching as described in U.S. Pat. Nos. 3,668,130 and 4,515,829, incorporated herein by reference. Neutralization prior to electroless metal deposition is also accomplished by methods well known to the art.
While there are many prior art processes for electroless metal deposition, a preferred process comprises the application of copper by a tin-palladium catalysis technique in which the surfaces on which the copper is to be deposited are activated and sensitized in order to catalyze the chemical surface reduction. This process is described in U.S. Pat. No. 3,011,920, incorporated herein by reference.
Following electroless plating, the substrate may be electrolytically plated by conventional means with copper, nickel, gold, silver, solder, chromium and the like to achieve the desired finish or thickness.
The following specific examples provide novel embodiments of the present invention. They are intended for illustrative purposes only and should not be construed as a limitation upon the broadest aspects of the invention. The examples illustrate various process steps used in operation with the disclosed invention and the results of adhesion testing done by IPC Test Methods 2.4.8 and/or 2.4.9.
The following descriptions of solutions or baths used in the examples should not be taken as limitations to the practice of the invention but as representative of solutions or baths typically used in the industry.
Chrome Etch 940 used is a solution of hexavalent chrome, sulfuric acid and water. Permanganate Etch MLB 213 is an alkaline permanganate solution. The Neutralizer PM 954 solution is a typical sulfate reducing solution. Catalyst Pre-Dip 404 contains hydrochloric acid and sodium chloride. Cataposit 44 is a typical tin-palladium catalyst. Accelerator 241 is an activating solution which contains a sulfonic acid. Electroless Copper Strike PM 994 is an auto-catalytic copper sulfate solution. Full Build Electrodeposit 272 solution is a standard acid copper formulation used for plating.
EXAMPLES
Examples 1-5 show the results of the pretreatment process of conditioning followed by a hot water rinse. Adhesion values obtained with this process are typically 8-16 lbs./linear inch depending upon the grade of substrate used. Example 6 shows the result of no pretreatment and values are typically 1-3 lbs./linear inch. Improvements in adhesion are found with the use of cold water or room temperature water rinses following pre-treatment with the conditioner as shown in Examples 7 and 8. The values for adhesion show a slight improvement over the practice of the invention without the conditioner. Values obtained with these water rinses are usually 4-6 lbs./linear inch, respectively.
EXAMPLE 1
Substrate--General Electric Ultem 2312 (polyetherimide resin/glass filler)
______________________________________ ImmersionProcess Sequence Time (min) Temp °C.______________________________________ 1. Butyrolactone (98-100%) 6 49 2. Hot Water Rinse 5 49 3. Chrome Etch PM 940 6 71 4. Rinse 5 RT 5. Neutralizer PM 954 6 65 6. Rinse 5 RT 7. Catalyst Pre-Dip 404 1 RT 8. Cataposit 44 6 43 9. Rinse 3 RT10. Accelerator 241 2 RT11. Rinse 3 RT12. Electroless Copper Strike PM 994 15 4313. Full Build Electrodeposit 272 45 RT14. Rinse 5 RT15. Bake 3 hrs. 121Results: 13 lbs./linear inch peel strength______________________________________
EXAMPLE 2
Substrate -- General Electric Ultem 3812 (polyetherimide resin/mineral/glass filler)
______________________________________ ImmersionProcess Sequence Time (min) Temp °C.______________________________________ 1. Butyrolactone (98-100%) 7 49 2. Hot Water Rinse 5 49 3. Chrome Etch PM 940 10 71 4. Rinse 5 RT 5. Neutralizer PM 954 5 65 6. Rinse 5 RT 7. Catalyst Pre-Dip 404 1 RT 8. Cataposit 44 6 43 9. Rinse 3 RT10. Accelerator 241 2 RT11. Rinse 3 RT12. Electroless Copper Strike PM 994 15 4313. Full Build Electrodeposit 272 45 RT14. Rinse 5 RT15. Bake 3 hrs. 121Results: 14 lbs./linear inch peel strength______________________________________
EXAMPLE 3
Substrate--General Electric Ultem 2312 (polyetherimide resin/glass filler)
______________________________________ ImmersionProcess Sequence Time (min) Temp °C.______________________________________ 1. Butyrolactone (98-100%) 6 71 2. Hot Water Rinse 5 49 3. Permanganate Etch MLB 213 15 71 4. Hot Rinse 2 49 5. Neutralizer PM 954 7 49 6. Rinse 5 RT 7. Catalyst Pre-Dip 404 1 RT 8. Cataposit 44 6 43 9. Rinse 3 RT10. Accelerator 241 2 RT11. Rinse 3 RT12. Electroless Copper Strike PM 994 15 4313. Full Build Electrodeposit 272 45 RT14. Rinse 5 RT15. Bake 3 hrs. 121Results: 8 lbs./linear inch peel strength______________________________________
EXAMPLE 4
Substrate--LNP Engineering Plastics EM 3240 (polyetherimide resin/glass filler)
______________________________________ ImmersionProcess Sequence Time (min) Temp °C.______________________________________ 1. Butyrolactone (98-100%) 8 49 2. Hot Water Rinse 5 49 3. Permanganate Etch MLB 213 18 71 4. Rinse 2 RT 5. Neutralizer PM 954 7 49 6. Rinse 5 RT 7. Catalyst Pre-Dip 404 1 RT 8. Cataposit 44 6 43 9. Rinse 3 RT10. Accelerator 241 2 RT11. Rinse 3 RT12. Electroless Copper Strike PM 994 15 4313. Full Build Electrodeposit 272 45 RT14. Rinse 5 RT15. Bake 3 hrs. 121Results: 11 lbs./linear inch peel strength______________________________________
EXAMPLE 5
Substrate--LNP Engineering Plastics EF 1004 (polyetherimide resin/glass filler)
______________________________________ ImmersionProcess Sequence Time (min) Temp °C.______________________________________ 1. Butyrolactone (98-100%) 8 49 2. Hot Water Rinse 5 49 3. Chrome Etch PM 940 8 71 4. Rinse 5 RT 5. Neutralizer PM 954 6 49 6. Rinse 5 RT 7. Catalyst Pre-Dip 404 1 RT 8. Cataposit 44 6 43 9. Rinse 3 RT10. Accelerator 241 2 RT11. Rinse 3 RT12. Electroless Copper Strike PM 994 15 4313. Full Build Electrodeposit 272 45 RT14. Rinse 5 RT15. Bake 3 hrs. 121Results: 10 lbs./linear inch peel strength______________________________________
EXAMPLE 6
Substrate--General Electric Ultem 2312 (polyetherimide resin/glass filler)
______________________________________ ImmersionProcess Sequence Time (min) Temp °C.______________________________________ 1. No Conditioner used 2. No Rinse Step 3. Chrome Etch PM 940 6 71 4. Rinse 5 RT 5. Neutralizer PM 954 6 65 6. Rinse 5 RT 7. Catalyst Pre-Dip 404 1 RT 8. Cataposit 44 6 43 9. Rinse 3 RT10. Accelerator 241 2 RT11. Rinse 3 RT12. Electroless Copper Strike PM 994 15 4313. Full Build Electrodeposit 272 45 RT14. Rinse 5 RT15. Bake 3 hrs. 121Results: 3 lbs./linear inch peel strength______________________________________
EXAMPLE 7
Substrate--General Electric Ultem 2312 (polyetherimide resin/glass filler)
______________________________________ ImmersionProcess Sequence Time (min) Temp °C.______________________________________ 1. Butyrolactone (98-100%) 6 49 2. Room Temperature Water Rinse 5 RT 3. Chrome Etch PM 940 6 71 4. Rinse 5 RT 5. Neutralizer PM 954 6 65 6. Rinse 5 RT 7. Catalyst Pre-Dip 404 1 RT 8. Cataposit 44 6 43 9. Rinse 3 RT10. Accelerator 241 2 RT11. Rinse 3 RT12. Electroless Copper Strike PM 994 15 4313. Full Build Electrodeposit 272 45 RT14. Rinse 5 RT15. Bake 3 hrs. 121Results: 6 lbs./linear inch peel strength______________________________________
EXAMPLE 8
Substrate--General Electric Ultem 2312 (polyetherimide resin/glass filler)
______________________________________ ImmersionProcess Sequence Time (min) Temp °C.______________________________________ 1. Butyrolactone (98-100%) 6 49 2. Cold Water Rinse 5 15 3. Chrome Etch PM 940 6 71 4. Rinse 5 RT 5. Neutralizer PM 954 6 65 6. Rinse 5 RT 7. Catalyst Pre-Dip 404 1 RT 8. Cataposit 44 6 43 9. Rinse 3 RT10. Accelerator 241 2 RT11. Rinse 3 RT12. Electroless Copper Strike PM 994 15 4313. Full Build Electrodeposit 272 45 RT14. Rinse 5 RT15. Bake 3 hrs. 121Results: 4 lbs./linear inch peel strength______________________________________ | A process for promoting the adhesion of metal to thermoplastic substrates such as polyimides. The improvement comprises conditioning the substrate by treating with a lactone and aqueous rinse prior to subsequent steps of etching and deposition of a metal coating. Use of the conditioner promotes increased adhesion between the substrate and the metal without loss of the cohesive integrity of the substrate throughout subsequent processing steps. | 2 |
FIELD OF THE INVENTION
[0001] The present invention relates to improvements in the technology relating to in water and underwater mechanical motive structures and particularly to improvements relating to an underwater device which is simplified, has a core and motive section which is modularized, and has an improved access structure which stably enables access.
BACKGROUND OF THE INVENTION
[0002] Powered underwater motive devices have been known since the 1950's. Most of those earlier devices were metal and were built like small submarines. Access was had through hatches which had to be securely bolted or clamped in order to resist taking on water at depth. Water is harmful to both motors and batteries and must be sealed out. As a result, the underwater motive devices were large, bulky and designed with a mind to limit outside access to limit the sealing areas provided for service access.
[0003] Recent improvements in underwater motive devices have related to the safety of operation, including a slight delay in starting to prevent inadvertent operation. In addition, sealed chambers have been introduced to keep water out of the battery and motor compartments.
[0004] However, for small motive devices, providing an integral housing complete with sealing of the battery and motor compartment has proved difficult for users to easily access the battery and motor compartment. The only alternative to a strong seal was unacceptable as a weaker seal would cause the taking of the device to depth to result in cyclical pressure leakage. Where the device is used in salt water, even the slightest leakage can be disastrous.
[0005] Seals achieve their integrity by resilient sealing force and area. Both force and area contribute to the necessity for high force of replacement and removal. In a prior underwater motive device, air pressure and a pump were utilized to provide internal assist pressure to unseal the battery and motive compartments. Battery exchange required some setup and interconnectivity time.
[0006] Design of underwater motive devices generally allow sealing to be accomplished most effectively during manufacturing and for manufactured components which will not thereafter be disturbed. Any time that a user access can be obtained, the ability to provide factory sealing is impaired. It has been previously difficult to provide user access without a statistical chance of breach of sealing.
[0007] Another goal for underwater motive devices is to insure as much as practical that the user is ready to power the device. The provision of an operation switch which is difficult to operate in order to prevent inadvertent operation is generally disadvantageous. Where the user needs frequent starting and stopping, the extra time spent fumbling with an “out of the way” switch will severely reduce the utility of the device. Conversely, the prominence of the switch can contribute to inadvertent actuation.
[0008] When stored in the powered, battery connected condition, inadvertent activation can deplete the battery. During use, inadvertent activation can cause the device to go out of a user's control.
[0009] What is needed is an underwater motive device which enables easy access to battery change out without diminishing the integrity of the sealed components. Battery change out should be able to be accomplished with ease, and by persons having limited strength. The needed underwater motive device should have a switching system which is handy yet contains safeguards against inadvertent activation and loss of control. Finally, a device is needed which can include factory sealing of most components with minimum sealing breach by the user.
SUMMARY OF THE INVENTION
[0010] An underwater motive device provides an integrated and modular battery and motive housing which is carried within an outer housing and secured by a nose cone system. The nose cone system works against an “o” ring seal carried between a structure of the integrated and modular battery and motive housing and the outer housing. A pair of latches act as levers to forcibly push the nose cone in place to seal off the battery compartment. The same pair of latch levers operate a slight cam which is used to urge the nose cone to a disengaged position with respect to the “o” ring seal. The underwater motive device is configured to enable operation of the nosecone latch when the underwater motive device is in the upright position, and incudes a sturdily supported propeller cowling which permits a stable, centered, supported upright position from which the nose cone removal and re-sealing procedure can be accomplished easily, even by those of limited strength.
[0011] The actuation buttons are prominently placed and easily found by touch and feel. One of the handles also includes a rearward lockout so that the underwater motive device can be stored in bulk without the possibility of inadvertent activation if both prominent activation buttons are depressed.
[0012] The integrated core assembly of the underwater motive device is used both as a sealing boundary, maintenance aid and a mechanism to limit the need for multi-location user access. The core unit includes an integral structure having a forward battery compartment with a bayonette connector wire leading to a sealed access to the rear sealed motor volume. A shaft from the motor extends through an opening in the rear compartment which enables extension out of the rear compartment while sealing the shaft against the core unit housing. The core unit housing fits through the center of the outer housing and is secured to the outer housing by threaded members. An “o” ring seal is place in a space between the forward peripherally radially extending lip and an adjacent structure of the outer housing is engaged by a sealing surface on the inside of the front nose cone to provide sealing integrity.
[0013] Even if water inadvertently enters the battery compartment, it cannot travel farther into the sealed motor compartment. If moisture is present in small amounts, it can be easily seen and removed each time the nose cone and battery compartment are accessed to change the battery. The completely sealed compartments then include the nose cone and battery compartment. The rearward sealed motor and shaft compartment remains independently factory sealed, even against the forward located nose cone and battery compartment.
[0014] The resulting underwater motive device is simple, easy to use, and can be quickly opened, its battery disconnected and a new battery re-connected, and closed for return to use in less than 30 seconds.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The invention, its configuration, construction, and operation will be best further described in the following detailed description, taken in conjunction with the accompanying drawings in which:
[0016] FIG. 1 is a perspective view of the underwater motive device of the present invention;
[0017] FIG. 2 is an exploded view of the underwater motive device of FIG. 1 and illustrating the inner core and its forward battery chamber and rearward motor compartment;
[0018] FIG. 3 is a perspective view of the front nose cone and latching assembly used to provide ease of front nose cone removal;
[0019] FIG. 4 is a lateral view looking into the latching assembly's cam structure used to mechanically advantageously lever the front cone away from the outer rear housing;
[0020] FIG. 5 is an expanded view of a thumb operated lockout mechanism mounted rearwardly on an integral side handle; and
[0021] FIG. 6 is a schematic view of the circuitry and controller connection with respect to the actuation switches.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0022] The description and operation of the invention will be best initiated with reference to FIG. 1 . An underwater motive device 21 has a seemingly integrated outer rear housing 23 which has seemingly continuous external lines with a front nose cone 25 . One of two identically numbered side latches is seen as a latch 27 which includes a latch frame member 29 which is pivotally mounted with respect to the forward end of the outer rear housing 23 . A pivoting engagement member 31 is pivotally attached to the inside forward end of the latch frame member 29 and has a rearward end which engages a projection 33 which is preferably integral with the nose cone 25 . As will be seen a rear inner portion of the latch frame member 29 includes a cam member to cause the nose cone 25 to be gently urged from its engagement to the front end of the outer rear housing 23 .
[0023] Features of the outer rear housing seen in FIG. 1 also include integral side handles 35 and 37 . A prominent actuation switch 39 is seen on side handle 35 while a prominent actuation switch 41 is seen on side handle 37 . A rounded propeller cowling 45 is seen at the rear of the outer rear housing 23 . Rounded propeller housing 45 is well supported by a set of four angular supports 51 , 53 , 55 and 57 ( 57 not being seen in FIG. 1 ). A series of net mesh panels 59 are supported in between pairs of adjacent angular supports 51 , 53 , 55 and 57 . Net mesh panels 59 are preferably resilient so as to withstand small bumps and spring back into place. The cross sectional area is preferably such that no significant pressure drop will occur for water flowing through the propeller housing 45 .
[0024] Referring to FIG. 2 , an expanded and exploded view of the underwater motive device 21 of FIG. 1 is shown. Beginning at the front of the nose cone 25 , the complete contour of the surfaces surrounding projection 33 show a smooth groove 61 slightly forward and inboard of the projection 33 projection 33 into which a matching surface rear end 63 latch 27 interfits. The smooth groove 51 enables the surface rear end 63 to rotatably pivot in a low-friction controlled matter to urge the nose cone 25 rearwardly against the front of the outer rear housing 23 .
[0025] Also seen in FIG. 2 are periodically occurring ribbed shaped cam surfaces 65 which will push nose cone 25 away from the front of the outer rear housing 23 when the latch frame members 29 are in a position near their fully open position. The pivoting engagement members 31 are shown in a position in which they would be enabled to fold toward the smooth grooves 61 , along with the inward folding of the latch frame members 29 , of the front nose cone 25 . This mechanical leverage is used to securely force the front nose cone 25 into sealing position. The cam surfaces 65 are used for mechanical leverage in the disengagement of the nose cone 25 .
[0026] Inboard of the smooth groove 61 slightly forward and inboard of the laches 27 , a raised edge 67 is the forward most projection of the inner core 69 , including a forward battery chamber 71 , and a rearward motor compartment 73 . Inner core 69 may be mounted in an offset, non-centered relationship with respect to the outer rear housing 23 to create a single possible interfitting relationship despite the bilaterally placed latches 27 .
[0027] Extending through the rearward most end of the motor compartment 73 is a shaft 75 . At the front inside of the forward battery chamber, at least two of four threaded members 77 are seen. Threaded members 77 engage a peripheral plate 79 onto a matching inset 81 .
[0028] Also seen just aft of raised peripherally extending edge 67 , is an “o” ring seal 83 . “o” ring seal 83 is preferably a continuous length of elastomeric material which extends significantly peripherally outwardly of the outward most peripheral extent of the edge 67 . The degree of compression of the “o” ring seal 83 is proportional to the amount of sealing and the sealing force involved in placing and removing the front nose cone 65 .
[0029] Just in front of the opening of the forward battery chamber 71 is a battery 85 having a pair of leads 87 leading to a keyed bayonette connector 89 . The bayonette connector has a male and a female portion so that the user cannot inadvertently reverse the polarity of connection, either to a charger or to a connector 91 which is stably mounted just inside the battery compartment 71 opening. Sufficient clearance remains between the battery 85 and the closest internal dimension of the inside of the forward battery chamber 71 to provide clearance for the pair of leads 87 while providing close support clearance to for an integral fit. The connector 89 can be connected and disconnected to the connector 91 while the battery 85 is in place within the forward battery chamber 71 .
[0030] Also seen through a partial cut away view of the net mesh panels 59 is a propeller 93 attached to the shaft 75 (not seen in FIG. 2 . Just to the rear of propeller 93 is seen a rear screen 97 which may be formed integrally with respect to the propeller cowling 45 . With both the rear screen 97 and net mesh panels 59 , water enters the area of the propeller 93 and is pushed rearwardly through the rear screen 97 while keeping fingers and large objects from entering the propeller 93 area. The propeller 93 can be accessed and removed from the shaft 75 , and the inner core 69 preferably by removing the propeller cowling 45 and an integrally attached rear screen 97 . The propeller cowling 45 may be preferably attached to an attachment ring 99 which may be integrally formed with the four angular supports 51 , 53 , 55 and 57 .
[0031] Referring to FIG. 3 , a closeup view of the latch 27 with the latch frame member 29 shown in its midpoint position is shown. Movement of the latch frame member 29 toward the front nose cone 25 will result in force from the angles of the latch frame member 29 and pivoting engagement member 31 to further urge the latch frame member 29 toward the front nose cone 25 in a “snap” action. Movement of the latch frame member 29 away from the front nose cone 25 will result in some force movement for a short angular extent, followed by a non-force assist opening of the latch 25 to a position near the position seen in FIG. 1 in which the front cone 25 is no longer axially held in place.
[0032] The action and movement of the last few degrees of the latch frame member 29 is shown in FIG. 4 . As it continues to angularly open, the cam surfaces 65 begin to engage a rear surface of the front nose cone 25 to urge it about a quarter inch away from the front of the outer rear housing 23 . This mechanical advantage helps the user break the seal between the outer periphery of the “o” ring seal 83 and a mating surface on the inside of the front nose cone 25 . This enables a user having a weak upper body strength to remove the front nose cone 25 with no more strength than would be required to open a suitcase hasp. A gap 101 is small but sufficient so to allow the front nose cone 25 to be removed.
[0033] Referring to FIG. 5 , a thumb lockout mechanism 105 is shown in one of the integral side handles, in this case integral side handle 35 . A slot 107 enables the movement of a sliding member 109 to a lower position enabling the actuation of the prominent actuation switches, in this case prominent actuation switch 41 . An upward position of the sliding member 109 blocks the engagement of the prominent actuation switch 41 .
[0034] Referring to FIG. 6 , an operating schematic illustrates the double actuation of the prominent actuation switches 39 and 41 necessary for operation of the underwater motive device 21 via a series connection. Battery 85 has one pole connected to a controller 111 and a second pole connected to controller 111 through a series connection of switches 39 and 41 . Controller 111 is utilized to create a delay to further downstream energization in order to make certain that the activation of the propeller 93 is intended by the user. Also shown is that the components forward of the shaft 75 lie within the inner core 69 .
[0035] Especially where the activation switches 39 and 41 are prominent, it is desired to have enough of a delay that the propeller 93 not start turning before the user has had a chance to adequately grip the integral side handles 35 and 37 . Controller 111 is electrically connected to a motor 113 which is mechanically connected to the shaft 75 and propeller 75 previously seen in FIG. 2 .
[0036] In terms of utilization, the underwater motive device 21 offers advantages previously not seen in underwater motive devices. The structures for accessing the battery make extended use of the underwater motive device 21 available to everyone, regardless of upper body strength. The unitary inner core 69 facilitates repair and replacement of the unitary inner core 69 should an internal malfunction occur.
[0037] While the present invention has been described in terms of an underwater motive device, & more particularly to a particular structure and system which utilizes a user-friendly battery access system, controller which provides power delay, and ease of servicing, this mechanism can be applied to other devices.
[0038] Although the invention has been derived with reference to particular illustrative embodiments thereof, many changes and modifications of the invention may become apparent to those skilled in the art without departing from the spirit and scope of the invention. Therefore, included within the patent warranted hereon are all such changes and modifications as may reasonably and properly be included within the scope of this contribution to the art. | An underwater motive device provides an integrated and modular battery and motive housing which is carried within an outer housing and secured by a nose cone system. The nose cone system works against an “o” ring seal carried between a structure of the integrated and modular battery and motive housing and the outer housing. A pair of latches act as levers to forcibly push the nose cone in place to seal off the battery compartment, and with cam action when used to urge the nose cone to a disengaged position with respect to the “o” ring seal. Nose cone removal and re-sealing procedure can be accomplished easily, even by those of limited strength. | 1 |
BACKGROUND OF THE INVENTION
[0001] The subject matter disclosed herein relates to gas turbine engines and, more particularly, to temperature and performance management therein.
[0002] In a gas turbine engine, air is pressurized in a compressor and mixed with fuel in a combustor for generating hot combustion gas that flows downstream through one or more turbine stages. A turbine stage includes a stationary nozzle having stator vanes that guide the combustion gas through a downstream row of turbine rotor blades. The blades extend radially outwardly from a supporting rotor that is powered by extracting energy from the gas.
[0003] A first stage turbine nozzle receives hot combustion gas from the combustor and directs it to the first stage turbine rotor blades for extraction of energy therefrom. A second stage turbine nozzle may be disposed downstream from the first stage turbine rotor blades, and is followed by a row of second stage turbine rotor blades that extract additional energy from the combustion gas. Additional stages of turbine nozzles and turbine rotor blades may be disposed downstream from the second stage turbine rotor blades.
[0004] As energy is extracted from the combustion gas, the temperature of the gas is correspondingly reduced. However, since the gas temperature is relatively high, the turbine stages are typically cooled by a coolant such as compressed air diverted from the compressor through the hollow vane and blade airfoils for cooling various internal components of the turbine. Since the cooling air is diverted from use by the combustor, the amount of extracted cooling air has a direct influence on the overall efficiency of the engine. It is therefore desired to improve the efficiency with which the cooling air is utilized to improve the overall efficiency of the turbine engine.
[0005] The quantity of cooling air required is dependant not only on the temperature of the combustion gas but on the integrity of the various seals which are disposed between rotating and stationary components of the turbine. Thermal expansion and contraction of the rotor and blades may vary from the thermal expansion of the stationary nozzles and the turbine housing thereby challenging the integrity of the seals. In some cases the seals may be compromised causing excess cooling air to pass into the turbine mainstream gas flow resulting in excess diversion of compressor air translating directly to lower than desired turbine efficiency.
[0006] It is therefore desired to provide a gas turbine engine having improved sealing of gas turbine stationary to rotating component interfaces.
BRIEF DESCRIPTION OF THE INVENTION
[0007] In an exemplary embodiment of the invention a turbine engine comprises a first, rotatable turbine rotor assembly, a second, stationary nozzle assembly disposed adjacent thereto and a wheel space which is defined between the first, rotatable turbine rotor assembly and the second, stationary nozzle assembly. The wheel space is configured to receive cooling air therein and includes a sealing feature located on the first rotatable turbine rotor assembly that extends axially into the wheel space to terminate adjacent to a sealing land positioned on the second, stationary nozzle assembly. The sealing feature and the sealing land operate to control the release of cooling air from within the wheel space and the sealing land is constructed of shape memory alloy.
[0008] In another embodiment of the invention a turbine engine comprises a first, rotatable turbine rotor assembly, a second, stationary nozzle assembly disposed adjacent thereto and a wheel space defined between the first, rotatable turbine rotor assembly and the second, stationary nozzle assembly and configured to receive cooling air therein. A sealing feature located on the first, rotatable turbine rotor assembly extends axially into the wheel space to terminate adjacent to a sealing land positioned on the second, stationary nozzle assembly. The sealing feature and the sealing land operate to control the release of the cooling air from within the wheel space; the sealing land constructed of shape memory alloy.
[0009] In another embodiment, a turbine engine comprises a turbine housing having an upstream and a downstream end. A stationary nozzle assembly is disposed within the housing in fixed relationship thereto. A turbine rotor assembly is supported within the housing for rotation therein and is operable, during operation of the turbine engine, to thermally expand in the downstream direction relative to the stationary nozzle assembly. A wheel space, defined between the stationary nozzle assembly and the rotatable turbine rotor assembly, is configured to receive cooling air therein. A sealing feature, located on the rotatable turbine rotor assembly and extending axially into the wheel space terminates adjacent to a sealing land positioned on the second, stationary nozzle assembly. The sealing feature and the sealing land operate to control the release of the cooling air from within the wheel space. The sealing land is constructed of shape memory alloy having a composition such that a phase changes from a cold, martensitic state to a hot, austenitic state is within the heat transient of the gas turbine engine. The shape memory alloy is configured as a two-way alloy having a first configuration in the cold, martensitic state and a second configuration in the hot, austenitic state and is operable to maintain the sealing feature adjacent the sealing land during thermal expansion of the turbine rotor assembly.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The invention, in accordance with preferred and exemplary embodiments, together with further advantages thereof, is more particularly described in the following detailed description taken in conjunction with the accompanying drawings in which:
[0011] FIG. 1 is an axial sectional view through a portion of an exemplary gas turbine engine in accordance with an embodiment of the invention;
[0012] FIG. 2 is an enlarged sectional view through a portion of the gas turbine engine of FIG. 1 ;
[0013] FIG. 3 is an enlarged sectional view through a portion of the gas turbine engine of FIG. 1 in a cold, non-operational state; and
[0014] FIG. 4 is an enlarged sectional view through a portion of the gas turbine engine of FIG. 1 in a hot, operational state.
DETAILED DESCRIPTION OF THE INVENTION
[0015] Illustrated in FIGS. 1 and 2 is a portion of a gas turbine engine 10 . The engine is axisymmetrical about a longitudinal, or axial centerline axis and includes, in serial flow communication, a multistage axial compressor 12 , a combustor 14 , and a multi-stage turbine 16 .
[0016] During operation, compressed air 18 from the compressor 12 flows to the combustor 14 that operates to combust fuel with the compressed air for generating hot combustion gas 20 . The hot combustion gas 20 flows downstream through the multi-stage turbine 16 , which extracts energy therefrom.
[0017] As shown in FIGS. 1 and 2 , an example of a multi-stage axial turbine 16 may be configured in three stages having six rows of airfoils 22 , 24 , 26 , 28 , 30 , 32 disposed axially, in direct sequence with each other, for channeling the hot combustion gas 20 therethrough and, for extracting energy therefrom.
[0018] The airfoils 22 are configured as first stage nozzle vane airfoils. The airfoils are circumferentially spaced apart from each other and extend radially between inner and outer vane sidewalls 34 , 36 to define first stage nozzle assembly 38 . The nozzle assembly 38 is stationary within the turbine housing 40 and operates to receive and direct the hot combustion gas 20 from the combustor 14 . Airfoils 24 extend radially outwardly from the perimeter of a first supporting disk 42 to terminate adjacent first stage shroud 44 . The airfoils 24 and the supporting disk 42 define the first stage turbine rotor assembly 46 that receives the hot combustion gas 20 from the first stage nozzle assembly 38 to rotate the first stage turbine rotor assembly 46 , thereby extracting energy from the hot combustion gas.
[0019] The airfoils 26 are configured as second stage nozzle vane airfoils. The airfoils are circumferentially spaced apart from each other and extend radially between inner and outer vane sidewalls 48 and 50 to define second stage nozzle assembly 52 . The second stage nozzle assembly 52 is stationary within the turbine housing 40 and operates to receive the hot combustion gas 20 from the first stage turbine rotor assembly 46 . Airfoils 28 extend radially outwardly from a second supporting disk 54 to terminate adjacent second stage shroud 56 . The airfoils 28 and the supporting disk 54 define the second stage turbine rotor assembly 58 for directly receiving hot combustion gas 20 from the second stage nozzle assembly 52 for additionally extracting energy therefrom.
[0020] Similarly, the airfoils 30 are configured as third stage nozzle vane airfoils circumferentially spaced apart from each other and extending radially between inner and outer vane sidewalls 60 and 62 to define a third stage nozzle assembly 64 . The third stage nozzle assembly 64 is stationary within the turbine housing 40 and operates to receive the hot combustion gas 20 from the second stage turbine rotor assembly 58 . Airfoils 32 extend radially outwardly from a third supporting disk 66 to terminate adjacent third stage shroud 68 . The airfoils 32 and the supporting disk 66 define the third stage turbine rotor assembly 70 for directly receiving hot combustion gas 20 from the third stage nozzle assembly 64 for additionally extracting energy therefrom. The number of stages utilized in a multistage turbine 16 may vary depending upon the particular application of the gas turbine engine 10 .
[0021] As indicated, first, second and third stage nozzle assemblies 38 , 52 and 64 are stationary relative to the turbine housing 40 while the turbine rotor assemblies 46 , 58 and 70 are mounted for rotation therein. As such, there are defined between the stationary and rotational components, cavities that may be referred to as wheel spaces. Exemplary wheel spaces 72 and 74 , illustrated in FIG. 2 , reside on either side of the second stage nozzle assembly 52 between the nozzle assembly and the first stage turbine rotor assembly 46 and the nozzle assembly and the second stage rotor assembly 58 .
[0022] The turbine airfoils as well as the wheel spaces 72 , 74 are exposed to the hot combustion gas 20 during operation of the turbine engine 10 . To assure desired durability of such internal components they are typically cooled. For example, second stage nozzle airfoils 26 are hollow with walls 76 defining a coolant passage 78 . In an exemplary embodiment, a portion of compressed air from the multistage axial compressor 12 is diverted from the combustor and used as cooling air 80 , which is channeled through the airfoil 26 for internal cooling. Extending radially inward of the second stage inner vane sidewall 48 is a diaphragm assembly 82 . The diaphragm assembly includes radially extending side portions 84 and 86 with an inner radial end 87 closely adjacent the rotor surface 88 . An inner cooling passage 90 receives a portion of the cooling air 80 passing through the airfoil coolant passage 78 and disperses the cooling air into the wheel spaces 72 and 74 to maintain acceptable temperature levels therein. Sealing features 92 and 94 , referred to as “angel wings”, are disposed on the upstream and downstream sides of the first stage turbine airfoils 24 . Similarly, sealing features 96 and 98 are disposed on the upstream and downstream sides of the second stage turbine airfoils 28 . The sealing features, or angel wings, extend in an axial direction and terminate within their associated wheel spaces closely adjacent to complementary sealing lands such as 100 and 102 , mounted in and extending from radially extending side portions 84 , 86 of the second stage diaphragm assembly 82 . During operation of the turbine engine, leakage of cooling air 80 , flowing into the wheel spaces 72 and 74 from the inner cooling passage 90 of the diaphragm assembly 82 , is controlled by the close proximity of the upstream and downstream sealing features 96 , 94 and the sealing lands 100 , 102 . Similar sealing features and sealing lands may also be used between stationary and rotating portions of the other turbine stages of the turbine engine 10 .
[0023] During operation of the gas turbine engine 10 , especially as the temperature of the engine transitions from a cold state to a hot state following start-up, the various components of the engine, already described above, may experience some degree of thermal expansion resulting in dimensional changes in the engine 10 which must be accounted for. For instance, as the temperature rises, the entire turbine rotor assembly 104 may expand axially relative to the fixed nozzle assemblies as well as the turbine housing 40 . Due to the manner in which the turbine rotor assembly 104 is supported within the turbine housing 40 , such axial expansion is primarily in the down stream direction relative to the housing, FIG. 1 . As a result of the downstream relative movement, the axial over-lap spacing between the downstream sealing features 94 of first stage turbine rotor assembly 46 and the second stage upstream sealing land 100 may increase, resulting in a decrease in the leakage of cooling air 80 into the main gas stream 20 from wheel space 72 . Conversely, the axial over-lap spacing between the second stage downstream sealing land 102 and the upstream sealing feature 96 of the second stage turbine rotor assembly 58 may decrease. Baring contact, the increase/decrease between sealing features is of minor consequence. However, since the cooling air 80 is diverted air from the axial compressor, its usage for purposes other than combustion will directly influence the efficiency of the gas turbine engine 10 and the designed operation of the wheel spaces. Each wheel space is designed to maintain a specific flow of cooling air to prevent the ingestion of the main gas stream 20 into the wheel space. Therefore, the decrease in axial over-lap spacing between the upstream sealing features 96 of second stage turbine rotor assembly 58 and the second stage downstream sealing land 102 is undesirable because the incorrect amount of flow is delivered to this wheel space 74 . Accordingly, wheel space 74 with its decrease in axial over-lap distance will leak more than the designed flow into the main gas stream 20 .
[0024] In one exemplary embodiment, the second stage downstream sealing land 102 comprises a band that is constructed of a two-way shape memory metal such as a nickel-titanium (“NiTi”) alloy. Shape memory alloy can exist in two different, temperature dependant crystal structures or phases (i.e. martensite (lower temperature) and austenite (higher temperature)), with the temperature at which the phase change occurs dependant upon the composition of the alloy. Two-way shape memory alloy has the ability to recover a preset shape upon heating above the transformation temperature and to return to a certain alternate shape upon cooling below the transformation temperature. Sealing land 102 is configured using a NiTi alloy having a phase change within the heat transient of the gas turbine engine 10 . Through a process of mechanical working and heat treatment, the land 102 is subject to a programming process in which the martensite configuration has an axially shorter length than the austenite configuration, which is axially longer. In some cases the martensite configuration may also be programmed to have a radially differing position relative to the radial sealing feature 96 than in the austenite configuration. As the gas turbine engine 10 transitions from cold to hot following start up, the sealing land 102 will proceed through its martensitic phase FIG. 3 , to its austenitic phase FIG. 4 , resulting in axial growth of the land and maintenance of the close physical spacing between the upstream sealing features 96 of second stage turbine rotor assembly 58 and the second stage downstream sealing land 102 regardless of the downstream axial growth of the turbine rotor assembly 104 . The result is reduced passage of cooling air 80 from within the downstream wheel space 74 between second stage turbine rotor assembly 58 and the diaphragm assembly 82 of the second stage nozzle assembly 52 , thereby improving the efficiency of the gas turbine engine and maintaining control of the wheel space cooling air flows. It is contemplated that, if desirable, the sealing land 102 may also be designed to include a radial as well as an axial change in clearance as the gas turbine engine 10 transitions from cold to hot.
[0025] In another embodiment of the invention, the second stage downstream sealing land 102 comprises a band that is constructed of a one-way shape memory metal such as a nickel-titanium (“NiTi”) alloy. Like two-way shape memory alloy, one-way shape memory alloy can exist in two different, temperature dependant crystal structures or phases (i.e. martensite (lower temperature) and austenite (higher temperature), with the temperature at which the phase change occurs dependant upon the composition of the alloy. Unlike two way shape memory alloy, one way allow has the ability to recover a preset shape upon heating above the transformation temperature following its mechanical deformation in the cold, martensite state. Upon cooling, the result of the mechanical deformation is erased. Sealing land 102 is configured using a NiTi alloy having a phase change within the heat transient of the gas turbine engine 10 . As the gas turbine engine 10 transitions from hot to cold following shutdown, the sealing land 102 will transition from its austenitic to its martensite state. Cooling of the turbine rotor assembly 104 results in the axial over-lap spacing between the sealing lands 102 and upstream sealing features 96 of second stage turbine rotor assembly 58 to increase. Following transition to the cold, martensitic phase the sealing land 102 may contact the sealing features 96 resulting in deformation of the sealing land. Following re-start of the gas turbine engine 10 and passage of the sealing land 102 through its martensitic to austenitic phase change the second stage downstream sealing land 102 will return to its un-deformed, initial state in close physical proximity to the upstream sealing features 96 of second stage turbine rotor assembly 58 . The result is reduced leakage of cooling air 80 from within the downstream wheel space 74 between second stage turbine rotor assembly 58 and the diaphragm assembly 82 of the second stage nozzle assembly 52 , thereby improving the efficiency of the gas turbine engine and maintaining control of the wheel space cooling air flows.
[0026] While exemplary embodiments of the invention have been described with application primarily to a second stage of a multi-stage turbine, the focused description is for simplification only and the scope of the invention is not intended to be limited to that single application. The application of the described invention can be applied to similar turbine engine assemblies and components throughout the various stages.
[0027] While exemplary embodiments of the invention have been described with reference to shape memory alloys of a nickel-titanium composition, other compositions such as nickel-metallic cobalt, copper-zinc or others, which exhibit suitable behavior at the desired temperatures of the turbine engine, may be utilized. In addition, the above description has been made with reference to an axial growth component in the seal land. It is recognized that due to the versatility of the shape memory alloys, the sealing land 102 may include a radial as well as an axial change in clearance from cold to hot.
[0028] This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims. | An exemplary embodiment of the invention is directed to a turbine engine having a first, rotatable turbine rotor assembly, a second, stationary nozzle assembly disposed adjacent thereto and a wheel space which is defined between the first, rotatable turbine rotor assembly and the second, stationary nozzle assembly. The wheel space is operable to receive cooling air therein and includes a sealing feature located on the first rotatable turbine rotor assembly that extends axially into the wheel space to terminate adjacent to a sealing land positioned on the second, stationary nozzle assembly. The sealing feature and the sealing land operate to control the release of cooling air from within the wheel space and the sealing land is constructed of shape memory alloy. | 5 |
FIELD OF THE INVENTION
The present invention relates generally to internal combustion engines, and more specifically to carbureted spark-ignition internal combustion engines with high compression ratios.
BACKGROUND OF THE INVENTION
In carbureted spark-ignition engines, one means of increasing the thermal efficiency (and thus the work output) of the engine is to increase the compression ratio, defined as the ratio of the maximum volume between the piston and the head to the minimum volume between the piston and the head. A higher compression ratio increases the thermal efficiency of the engine. It is therefore desirable for high-performance engines to have the greatest compression ratio possible.
However, the compression ratio cannot be increased indefinitely. The higher compression ratio causes higher temperatures and pressures in the combustion chamber's fuel-air mixture upon compression, thereby increasing the possibility of rapid self-ignition of the fuel-air mixture at some unplanned point during the work cycle. Such an event is commonly referred to as "knock" or autoignition.
A high degree of autoignition is undesirable because it lowers the engine efficiency and it also increases the chances of engine failure. Engine efficiency drops when autoignition occurs because cylinder gas expansion occurs at a time when its work potential cannot be fully utilized. For maximum work output, ignition is best begun shortly before the piston reaches top dead center so that peak combustion chamber pressures occur shortly after the piston reaches top dead center. Peak pressures at this point allow the work generated by the expanding combustion gases to be utilized over the greatest length of piston travel. The rapid pressure increases associated with autoignition can cause peak pressures to occur before this point, perhaps when the piston has not yet reached top dead center, thereby causing work losses by opposing the piston motion. Further, autoignition promotes heat losses from the engine because the combustion gases vibrate and "scrub" the cylinder walls as the shock wave from autoignition travels through the cylinder. Autoignition can also cause premature engine failure due to the extremely high temperatures it causes in the cylinder, as well as from the damage it causes by stress from the shock waves.
Autoignition is frequently triggered in high compression ratio engines by the normal process of ignition. The spark plug (or plugs) ignites the compressed fuel-air mixture, and as the flame front begins to travel from the spark site through the chamber, the end gas--the fuel-air mixture in the cylinder farthest away from the spark plug(s)--is additionally compressed by the expansion of the gases behind the flame front. The mixture is already at a state of high temperature and pressure due to its previous compression, and if this additional compression of the end gas causes further temperature and pressure increases, the end gas may autoignite.
While autoignition may be decreased by using a fuel with a higher octane rating--and therefore a higher ignition temperature--it is also helpful to increase the speed of combustion, leaving little time for autoignition of the end gas to occur. A number of steps may be taken to increase the rate of combustion, such as the use of modified fuels or multiple spark plugs. Another method involves increasing the turbulence in the combustion chamber immediately prior to and during combustion. Turbulence within the chamber causes the uniform flame front within the combustion chamber to distort, creating a more convective mode of heat transfer and sending "tongues" of highly reactive radicals from the flame front into the unburned mixture. These conditions combine to promote more rapid combustion of the unburned mixture than would occur in a quiescent, low-turbulence mixture.
While some turbulence is created within the combustion chamber by the mere act of the piston compressing the air-fuel mixture, the effect can be heightened by modifying the shape of the combustion chamber so that the motion of the piston interacts with the chamber contours to cause greater turbulence during compression. It is especially desirable if the greatest turbulence occurs in the end gas near the end of the compression stroke, just before ignition. Examples of chamber configurations designed to promote mixing and/or turbulence are found in U.S. Patents 4,838,222, 4,844,040, 5,115,774, and 5,115,776.
It is further desirable for the combustion period to be approximately constant, when measured in crankshaft degrees, over the range of speeds at which the engine will operate. This insures that regardless of engine speed, the expanding combustion gases will exert their peak pressures when the piston is at approximately the same position. A constant combustion period further insures that as the engine speed increases, thereby decreasing the compression time and causing more rapid temperature and pressure increases, the time for autoignition to occur will be proportionately decreased. A near-constant combustion period can be accomplished if the combustion chamber can be designed so that turbulence increases as engine speed is increased.
Autoignition is present in almost all internal combustion engines to some extent, and is difficult to totally eliminate. The goal of high-performance engine design is to minimize autoignition to such an extent that it no longer harms the engine's performance or its structure, while at the same time obtaining the highest compression ratio possible.
SUMMARY OF THE INVENTION
The internal combustion engine of the present invention operates with a high compression ratio while allowing the use of standard fuel. More specifically, the invention provides a carbureted spark-ignition engine particularly suited for motorcycles, with a high compression ratio, for example, on the order of 83/4:1 to 17:1, which may operate on standard fuel without undue autoignition. The invention is able to attain this increased compression ratio by heightening the turbulence in the end gas. Further, autoignition is minimized at all operating states of the engine by increasing the turbulence in the end gas as the engine speed is increased so that the combustion period is approximately constant, when measured in crankshaft degrees, at all engine operating states. In this manner, the engine is able to achieve superior power output at all speeds without the damage and inefficiency associated with autoignition. Further, since the increased turbulence in the combustion chamber enhances combustion throughout the chamber, more complete combustion is obtained, leading to an increase in fuel economy and a reduction in the emission of unburnt hydrocarbons.
An engine assembly in accordance with the invention includes a cylinder head, a cylinder block, and a piston (or pistons) which reciprocates in a cylinder within the block. The cylinder head and block are attached to each other at a cylinder head mating surface and a cylinder , block mating surface. The cylinder head includes an inlet valve and inlet port, an exhaust valve and an exhaust port, a cylinder head combustion chamber, and the cylinder head mating surface. The shape of cylinder head portion of the combustion chamber is defined by a recess in the cylinder head mating surface extending towards the interior of the cylinder head. The recess includes a depression which is bounded at its periphery in part by a chamber shoulder, and this chamber shoulder is in turn bounded by a beveled rim surface extending from the periphery of the chamber shoulder to the cylinder head mating surface. The wall of the depression includes an inlet valve seat, an exhaust valve seat, and a spark plug seat in which a spark plug is mounted. When the inlet and exhaust valves are closed, their heads rest in their respective inlet and exhaust valve seats and form a barrier between the combustion chamber and the inlet and exhaust ports. The inlet valve seat and exhaust valve seat may extend beyond the periphery of the depression, thereby overlapping the chamber shoulder and/or the beveled rim surface and interrupting one or both of them. Thus, the chamber shoulder and beveled rim surface may exist in discrete segments which are interrupted by the valve seats, rather than continuously extending around the entire periphery of the depression.
In a preferred embodiment of the invention, the depression has a substantially semiovoidal surface, shaped similarly to an ellipsoid which is cut at a plane parallel to its major axis of rotation. The inlet and exhaust valve seats sit on opposite ends of the major axis at positions near the cylinder head mating surface and extend into the depression. The exhaust valve is preferably somewhat smaller than the intake valve. The ignition means, e.g., a single spark plug, is located on one side of the major axis between the valve seats. The chamber shoulder and the beveled rim surface preferably do not extend around the entire perimeter of the depression. They instead exist in two segments, each segment laying opposite to one another between the inlet and exhaust valve seats. While the segments extend so far as to end at the periphery of the intake valve seat at one side of the combustion chamber, they do not extend to the periphery of the smaller exhaust valve seat at the other side of the combustion chamber, and the surface of the depression surrounds much of the exhaust valve seat. Further, while the surface of the depression is substantially semiovoidal and thus has an oval periphery, the segments of the beveled rim surface do not conform to the arc of the oval periphery on either side of the major axis; the beveled rim surface exists as a straight planar segment extending from the region near the exhaust valve up to a point near the minor axis of the oval periphery, at which point it then curves towards the inlet valve.
The block of the engine includes a cylinder (or plural cylinders), a piston which reciprocates within the cylinder, and the cylinder block mating surface. The piston has a piston top face which includes a piston face reference surface and a raised piston face surface. When the piston is at top dead center, the piston face reference surface lies substantially in the plane of the block mating surface. The raised piston face extends above the plane of the piston face reference surface and comprises a beveled boundary surface, a raised planar face surface, and optionally a beveled valve clearance surface. The raised planar face surface is spaced above the piston face reference surface and is bounded by the beveled boundary surface, which extends from the raised face surface to the piston face reference surface. Therefore, when the piston is at top dead center, the raised planar face surface extends beyond the cylinder block mating surface and into the combustion chamber. At this point, a peripheral portion of the raised planar face surface closely approaches and is parallel to the chamber shoulder, and the beveled boundary surface closely approaches and is parallel to the beveled rim surface. This close approach of these surfaces produces strong currents in the combustion chamber as the piston approaches top dead center, by driving the fuel-air mixture from between these parallel surfaces into the combustion chamber. Additional squish currents are generated as the piston face reference surface closely approaches the portion of the cylinder head mating surface immediately adjacent to the combustion chamber.
If a portion of the chamber shoulder is wider than at other positions on the chamber shoulder, the piston will push a greater volume of gas from the space between this larger shoulder area and the raised piston surface than from other positions on the shoulder. The squish current generated at this point will therefore have greater velocity than at the other points, and greater turbulence will be induced in the area of the combustion chamber opposite this point. In the preferred embodiment of the invention, a larger shoulder is used opposite the spark plug to generate greater turbulence across the combustion chamber toward the spark plug immediately prior to and during ignition to assist in a more rapid and uniform ignition of the fuel-air mixture in the chamber.
The valve seats within the combustion chamber may extend beyond the periphery of the depression and onto the chamber shoulder and/or the beveled rim surface. To avoid having portions of the raised piston face strike the valve heads when the piston approaches top dead center, beveled valve clearance surfaces are provided on the raised piston face. These surfaces are recessed from the raised piston face so that the piston does not collide with the valve heads when the piston reaches top dead center. The beveled valve clearance surfaces are shaped such that they closely approach and are substantially parallel to the valve heads at top dead center, thereby producing additional squish currents by driving the fuel-air mixture from between these surfaces and the valve heads and into the main volume of the combustion chamber.
The engine of the invention is particularly suited for use in motorcycles. Depending on the performance requirements for the engine, the compression ratio of the engine may be reduced by forming a depression in the center of the piston face, thereby lowering the compression ratio and allowing the use of lower octane fuels, and allowing greater flexibility for use of head and piston kit with different displacement engines. The entire engine may be installed within a motorcycle as a unit, or the cylinder head or piston may be installed within a motorcycle engine of similar and compatible type. The cylinder head and piston may be provided as a kit so that it will be possible to install both the cylinder head and piston in existing motorcycle engines.
Further objects, features, and advantages of the invention will be apparent from the following detailed description when taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings:
FIG. 1 is a cross-sectional view of a portion of an engine in accordance with the present invention, showing the cylinder head assembly, the cylinder block, and the piston.
FIG. 2 is a cross-sectional view of the engine of FIG. 1 when the piston is at top dead center.
FIG. 3 is a cross-sectional view of the engine of FIG. 2, when the piston is at top dead center, viewed at a point 90 degrees around the axis of the cylinder from FIG. 2 and generally along the lines 3--3 of FIG. 2.
FIG. 4 is a schematic view of the approximate volume defined by the combustion chamber of FIG. 3.
FIG. 5 is a schematic view of the approximate volume of the combustion chamber showing the additional chamber volume of the depression when a modified piston, with a depression in the piston top face, is used.
FIG. 6 is a plan view of the cylinder head, showing the inner walls of the combustion chamber within the cylinder head.
FIG. 7 is a plan view of the piston showing its top face.
FIG. 8 is a perspective view of the piston of FIG. 7.
FIG. 9 is a plan view of a piston modified by the formation of a depression on the piston top face.
FIG. 10 is a perspective view of the modified piston of FIG. 9.
DETAILED DESCRIPTION OF THE INVENTION
With reference to the drawings, a cross-sectional view of a carbureted spark-ignition internal combustion engine assembly in accordance with the invention is shown in FIG. 1. The engine assembly includes a cylinder head 10 which is mounted atop a cylinder block 12. The head includes an intake valve 14, an intake valve guide 16, an intake port 18, an exhaust valve 20, an exhaust valve guide 22, and an exhaust port 24. Within the cylinder head 10, a combustion chamber 26 is formed which includes a beveled rim surface 28, a planar chamber shoulder 30, composed of separated portions 30A and 30B, as shown in FIG. 3, and walls defining a depression 32. Other views of the cylinder head 10 are shown in FIGS. 3 and 6, with a cross-sectional view in FIG. 3 and a plan view in FIG. 6; these will shortly be discussed in greater length. The cylinder block 12 has a cylinder defined by a cylindrical wall 33, within which a piston 34 reciprocates. The piston 34 pivots about an wrist pin 36 which attaches the piston to a connecting rod 38. A piston top face 40 includes a piston face reference surface 42, and a raised piston face 44 which includes a beveled boundary surface 46, beveled valve clearance surfaces 48, and a raised planar face surface 50. The view shown in FIG. 1 is of the engine as it undergoes its intake stroke, indicated by the head 51 of the intake valve 14 clearing an intake valve seat 52. At this point, the head 53 of the exhaust valve 20 is nested within an exhaust valve seat 54. As illustrated in FIGS. 1 and 2, a planar cylinder head mating surface 58 is mounted in adjoining relation to a cylinder block mating surface 56 with a head gasket 59 between the two surfaces. For clarity of illustration, other standard parts of the engine (e.g., the crankshaft, valve lifters, camshaft, push rods, etc.) are not shown in FIGS. 1 and 2, and any suitable parts may be used. The engine (e.g., an air cooled motorcycle engine) may also have two or more cylinders constructed as described.
FIG. 2 shows a cross-sectional view of the engine assembly as in FIG. 1 but at the point when the piston 34 is at top dead center. FIG. 3 shows a cross-section of the engine of FIGS. 1 and 2 along a section line rotated 90 degrees around the cylinder axis from FIGS. 1 and 2. At top dead center, the raised piston face 44 extends beyond the mating surface 56 of the cylinder block 12 and into the combustion chamber of the cylinder head 10. The beveled boundary surface 46 of the piston closely approaches and is parallel to the beveled rim surface 28 in the cylinder head 10. Similarly, edge portions of the raised planar face surface 50 closely approach the chamber shoulders 30A and 30B in the cylinder head, and edge portions of the piston face reference surface 42 closely approach the cylinder head mating surface 58. A squish current is generated when the fuel-air mixture between the approaching surfaces 46 and 28, 50 and 30A and 30B, and 42 and 58, is rapidly compressed as the piston 34 approaches top dead center, and the fuel-air mixture between these surfaces is driven at high velocity into the combustion chamber 26. The beveled valve clearance surfaces 48 (as shown as hidden lines in FIGS. 1 and 2) allow the piston 34 to clear the heads 51 and 53 of valves 14 and 20, respectively, when the piston is at top dead center, allowing the piston to reach a position closely adjacent to the valve heads and thereby producing additional squish currents.
FIG. 4 is an idealized schematic side view of the approximate volume defined by the combustion chamber at top dead center. In the preferred embodiment, the cylinder head combustion chamber has a volume 70 which is much greater than the main "squish volume" 72 (the volume defined between the raised piston face surface 50 and the chamber shoulders 30A and 30B) and between the beveled boundary surface 46 and the beveled rim surface 28. For example, if the combustion chamber 70 has a volume of 112.5 cubic centimeters (cc), then the squish volume 72 may have a volume of, for example, 12.9 cc. FIG. 5 illustrates the volume defined by the combustion chamber at top dead center with a modified piston having a depression in the piston top face 40 which adds a volume 74 (of, for example, 43.1 cc), to the combustion chamber 26 to reduce the overall compression ratio.
FIG. 6 is a view of the cylinder head 10 showing the combustion chamber 26 and the cylinder head mating surface 58. As shown therein and in FIG. 1, the intake valve 14 and intake valve seat 52, exhaust valve 20 and exhaust valve seat 54, and a spark plug 80 are all mounted on the depression wall 32 which defines part of the combustion chamber in the head. The depression wall 32 is bounded on two sides by the chamber shoulders 30A and 30B, which are in turn bounded by the beveled rim surfaces 28. The chamber shoulder 30A, at a position opposite the spark plug 80, is preferably wider than the chamber shoulder 30B on the same side of the combustion chamber 26 as the spark plug 80. The wider chamber shoulder 30A causes a greater volume of fuel-air mixture to be driven away from the approaching surfaces at the area of the shoulder 30A as the piston 34 approaches top dead center than from the area of the chamber shoulder 30B, thereby creating a higher-velocity squish current and more turbulence which extends across the combustion chamber to the vicinity of the spark plug 80. Since ignition occurs shortly before the piston 34 reaches top dead center, the especially turbulent conditions near the spark plug 80 during ignition help the flame front, which is advancing outward from the spark plug 80, to distort and spread rapidly through the combustion chamber 26.
The depression 32 defining the combustion chamber has a substantially semiovoidal shape (a portion of an ellipsoid), with the heads of the intake valve 14 and the exhaust valve 20 laying near the ends of the ellipsoid on its major axis. The periphery of the combustion chamber 26, labeled as the line 84 along the cylinder head mating surface 58, is not quite ovate; the periphery surrounding the intake valve seat 52 more closely approaches this valve seat than it does the exhaust valve seat 54. This exposes a greater area on the cylinder head mating surface 58 to the piston face reference surface 42, and thereby also helps to create more vigorous squish currents in the combustion chamber 26. As best shown in the views of the piston 34 in FIGS. 7-10, the top face 40 of the piston is appropriately formed to match the periphery 84 of the cylinder head portion of the combustion chamber. The piston face reference surface 42 has at least one and preferably two widened portions 42A. The beveled boundary surface 46 has at least one and preferably two substantially straight portions 46A which extend from the widened portions 42A of the piston face reference surface to the raised piston face surface 50. The two widened portions 42A of the piston reference surface are preferably arranged to lie adjacent opposite sides of one of the valve seats, e.g., adjacent to the beveled valve clearance surfaces 48 for the exhaust valve, when the piston is at top dead center. The beveled boundary surface 46, including the substantially straight portions 46A, are bounded by the piston face reference surface 42, which includes the widened portions 42A thereof. The beveled boundary surface 46, including the straight portions 46A as best shown in FIG. 7, and the beveled rim surface 28, including substantially straight portions 28A thereof as shown in FIG. 6, are formed to match, so that at top dead center the beveled boundary surface 46 of the piston closely approaches and is parallel to the beveled rim surface 28.
FIGS. 7 and 8 illustrate the piston 34 and particularly the piston top face 40. The raised face surface 50 is bounded by the beveled boundary surface 46 and also by the beveled valve clearance surfaces 48. At top dead center, the raised face surface 50 closely approaches the chamber shoulders 30A and 30B in the cylinder head 10 to produce the squish volume 72 depicted in FIG. 4. Further, at top dead center, the beveled boundary surface 46 closely approaches the beveled rim surface 28, the beveled valve clearance surfaces 48 closely approach the head 51 of the intake valve 14 and the head 53 of the exhaust valve 20, and the piston face reference surface 42 closely approaches the cylinder head mating surface 58, all creating squish currents.
Within standard IC engines, the area near the wall of the combustion chamber generally contains a higher concentration of unburnt hydrocarbons during and after combustion due to the more quiescent boundary layer conditions adjacent to the chamber wall. Because the squish currents within the invention greatly enhance the turbulence within the combustion chamber, the boundary layer is invaded by plumes of hot gases and reactive radicals during combustion, and greater amounts of unburnt hydrocarbons are consumed by the combustion process. This decreases the amount of unburnt hydrocarbons in the engine exhaust, and it also increases the fuel economy of the engine because lesser amounts of unburnt hydrocarbon chains escape the combustion chamber without contributing to the work output of the combustion process.
The cylinder head 10 and mating piston 34 may be provided together as a kit and installed on existing engines to provide enhanced performance of the engine.
FIGS. 9 and 10 illustrates a piston 34 which is modified by the addition of a depression 74 in the piston face. The depression 74 increases the combustion chamber volume (e.g., by 43.1 cc for the exemplary engine dimensions given above) and decreases the compression ratio to a level more appropriate for lower octane gasoline. An idealized schematic representation of the combustion chamber with the piston depression 74 is shown in FIG. 5. It is understood that the depression 74 in the piston will generally have a flat bottom 88, as illustrated in FIGS. 9 and 10, to ensure that the top wall of the piston under the depression is of adequate thickness.
Raised vanes 90 and 91 as shown in FIG. 2 may be formed in the walls of the intake port 18 and exhaust port 24 adjacent the valve seats as shown in FIGS. 1 and 2 to enhance the flow of gases into and out of the cylinder. These vanes, which are preferably cast integrally with the head, help to strengthen the floor of the intake and exhaust ports, in addition to diverting gas flow around the intake and exhaust valves. The enhanced flow of gases into and out of the combustion chamber further increases the efficiency of the engine.
It is understood that the invention is not confined to the particular construction and arrangement of parts herein illustrated and described, but embraces such modified forms thereof as come within the scope of the following claims. | An internal combustion engine has a cylinder head with a combustion chamber defined by a depression in the head. The raised face surface of a piston extends into the combustion chamber in the cylinder head as the piston approaches top dead center, and creates turbulent squish currents within the chamber as closely matching surfaces on the piston face and on the walls of the combustion chamber in the head force gases out from between these surfaces. The turbulence helps to prevent autoignition and allows higher compression ratios than would otherwise be possible. | 5 |
TECHNICAL FIELD
[0001] The present invention is directed to methods of attaching seat covers during the manufacture of automotive seats, and to seat cushions manufactured by such methods.
BACKGROUND
[0002] In recent years seats for cars and light trucks have been formed by molding a foam bun that will serve as the seat cushion, and then attaching a pre-stitched fabric cover to the foam bun. Often, the fabric cover is attached to the foam bun by insert molding touch fastener strips into the outer surface of the foam bun and attaching cooperating touch fastener strips to an inner surface of the fabric cover. Generally, the fastener strips are attached to the fabric cover along the seams where the cover is stitched together, and held in place by the seam stitching. The touch fastener strips allow the seat manufacturer to rapidly and semi-permanently attach the fabric cover to the foam bun by pulling the fabric cover over the foam bun and pressing the opposed touch fastener strips on the foam bun and fabric cover together.
[0003] The touch fastener strips on the foam bun are typically recessed in trenches, to allow the seams in the fabric cover to be indented below the surface of the seat cushion. Indenting the seams in this manner forms aesthetically appealing indented creases in the surface of the seat cushion upholstery for a tailored look. The trenches also accommodate the additional thickness of upholstery fabric that is created where the seam is stitched.
[0004] For example, a foam bun 10 , shown in FIG. 1, includes a central, generally planar portion 12 and a pair of bolsters 14 , 16 disposed on either side of the central portion 12 . The central portion 12 and bolsters 14 , 16 are separated by trenches 18 which define sweeping curves. Trenches 18 are located in the seat cushion at the point of change in curvature formed where the surface of bolsters 14 , 16 on the side of seat cushion 10 intersect central portion 12 .
[0005] As shown in FIG. 2, touch fastener strips 24 are bonded to the bottom surface 17 of trenches 18 , e.g., by insert molding the foam bun 10 onto the touch fastener strips 24 with hook elements 25 exposed for engagement with cooperative fastener strips 27 that are sewn to the fabric cover 29 along seams 31 . Because the trenches 18 are indented below the surface 33 of the central portion 12 , when the cooperative touch fastener strips 27 are pressed against the touch fastener strips 24 the double thickness of fabric 35 that is below seam 31 will be recessed in the trenches, resulting in a smooth outer surface at the seam area of the seat cover.
[0006] This attachment method works well for fabric covers having straight seams. However, if the fabric cover has seams that define sweeping curves, e.g., seams that have a curvature similar to that of trenches 18 in FIG. 1, problems occur because as the touch fastener strip extends around the curve in the trench the strip will tend to buckle. Seat designs having curved seams have become increasingly popular in the automotive industry, and thus attempts have been made to address this problem. Some manufacturers have cut and pieced together short sections of straight touch fastener strips. Other manufacturers have cut out curved sections from wider strips of touch fastener material. Both methods may result in an inefficient, time consuming process, waste material, and undesirably high production costs.
[0007] Alternately, touch fastener strips have been custom molded to accommodate the shape of a curved trench. This alternate solution results in custom-molded touch fastener strips that can only be used for trenches with a particular degree of curvature, increasing the cost of production and requiring the seat manufacturer to inventory a variety of different custom-molded touch fastener strips for trenches having different degrees of curvature.
SUMMARY
[0008] In one aspect, the invention features methods of attaching a fabric cover to a foam bun that allow a continuous length of a relatively straight touch fastener strip to be used in a trench that defines a sweeping curve.
[0009] The inventor has found that, by configuring the trench so that its bottom surface is inclined, a long, straight touch fastener strip can be positioned to extend around a sweeping curve in the trench without buckling of the strip. This eliminates that need to cut and piece fastener strip sections together to form sweeping curves (e.g., curves having a radius of curvature of greater than about 15 inches), and allows the seat manufacturer to stock a single type of touch fastener strip for use in manufacturing seat cushions with seams that have varying degrees of sweeping curves. In some cases, more dramatic curves can be obtained with limited cutting and piecing (e.g., with two fastener strips) or with a single fastener strip.
[0010] Narrower trenches are typically desirable, as they may enhance the aesthetic appearance of the finished seat. Generally, the width of the trench is dictated by the width of the fastener strip. However, by using an inclined trench, a narrow trench may be obtained without changing the width of the fastener strip. The depth of the trench may be increased vary to further contribute to the aesthetically desirable appearance of the seam in the finished seat. Advantageously, this improved aesthetic appearance can be obtained using the same tooling and manufacturing procedures that many seat manufacturers are currently using (the only change being the configuration of the trenches).
[0011] In one aspect, the invention features a seat cushion including a foam bun which includes a central region bounded on opposite sides by elongated trenches. Disposed in each trench is an elongated touch fastener strip having an exposed surface which contains a plurality of fastener elements. At least a portion of one of the elongated trenches has a bottom surface that is inclined with respect to the central region.
[0012] In some embodiments, at least a portion of the bottom surface of the trench is inclined so that in a cross-section taken generally perpendicular to the trenches, the bottom surface of at least a portion of the trench defines an included angle with respect to a plane which is generally perpendicular to the centerline of the seat. In some cases the included angle is from about 10 to 80 degrees. In other cases the included angle is from about 30 to 60 degrees.
[0013] In some embodiments, the elongated trenches include opposing side walls and the bottom surface is positioned between these side walls.
[0014] In certain embodiments, at least a portion of the bottom surface of one of the trenches is inclined at an angle selected to allow the fastener strip to extend around a sweeping curve having a radius of curvature of at least about 15 inches. In other embodiments at least a portion of one of the trenches defines a sweeping curve having a radius of curvature greater than about 15 inches.
[0015] In some embodiments, the seat cushion has a fabric cover, wherein the inner surface of the cover carries a second elongated touch fastener strip which is positioned to engage the touch fastener strip on the foam bun. In some cases the fastener elements on the seat cushion include male fastener elements, and the second touch fastener strip on the cover includes a loop material.
[0016] In some embodiments the seat cushion also has a pair of bolster regions, where the elongated trenches are disposed between the central region and the bolster regions. The central region may be configured to support the back of a person sitting in the seat cushion, or may be configured to define the bottom of the seat.
[0017] According to another aspect, the invention features a method of forming a seat cushion including a foam bun. The method includes providing a mold cavity which has a shape corresponding to the shape of the foam bun, including a central portion bounded by elongated mold valleys. At least a portion of the bottom surface of one of the mold valleys is inclined with respect to the central region. The method also includes placing a touch fastener strip into each of the mold valleys, and delivering foam to the mold cavity.
[0018] In some embodiments of this method, at least a portion of the bottom surface of one of the elongated mold valleys is inclined so that in a cross-section taken generally perpendicular to the mold valley, the bottom surface of at least a portion of the mold valley defines an included angle with respect to a plane which is generally perpendicular to the centerline of the seat. In some cases the included angle is from about 10 to 80 degrees. In other cases the included angle is from about 30 to 60 degrees. At least a portion of the bottom surface of one of the mold valleys may be inclined at an angle selected to allow the touch fastener strip to extend around a sweeping curve having a radius of curvature of at least about 15 inches.
[0019] According to another aspect, the invention features a mold for forming a foam bun includes a mold cavity having a shape corresponding to the shape of the foam bun, including a central region and a pair of bolder-defining regions. Between the central region and the bolster-defining regions are a pair of elongated mold valleys, wherein the bottom surface of at least a portion of one of the mold valleys is inclined at an angle with respect to the central region.
[0020] In some embodiments, the mold has elongated mold valleys which are inclined so that in a cross-section taken generally perpendicular to the mold valleys, at least a portion of one of the bottom surfaces of the mold valleys defines an included angle with respect to a plane which is perpendicular to the centerline of the seat. In some cases the included angle is from about 10 to 80 degrees. In other cases the included angle is from about 30 to 60 degrees.
[0021] In certain embodiments, at least a portion of one of the bottom surfaces of the mold valleys is inclined at an angle selected to allow the fastener strip to extend around a sweeping curve having a radius of curvature of at least about 15 inches.
[0022] In some embodiments the mold has a central region which defines a central back-supporting or seat bottom area of the foam bun, and a bolster-defining region which defines bolster areas of the foam bun.
[0023] According to another aspect, the invention features a seat cushion including a foam bun which includes a first, generally planar region, and a second, generally non-planar region, wherein the second region has an inclined surface. An elongated touch fastener strip has a first surface which is bonded to the inclined surface, and a second surface which carries a plurality of fastener elements.
[0024] In some embodiments, the foam bun of this seat cushion has a trench which extends between the first and second regions.
[0025] According to a further aspect, the invention features a seat cushion including a foam bun which includes a first, generally planar central region and a second, generally non-planar region, these first and second regions being separated by an elongated trench, the trench having a bottom surface wherein at least a portion of the bottom surface is inclined to form an included angle with respect to a plane that is perpendicular to the centerline of the seat. The included angle is from about 10 to 80 degrees. Disposed in this trench is an elongated touch fastener strip having a first surface that is bonded to the bottom of the trench and a second surface that carries a plurality of fastener elements. Covering an outer surface of the foam bun is a fabric cover. The fabric cover has an inner surface carrying a second elongated touch fastener strip that is positioned to engage the touch fastener strip on the foam bun.
[0026] Other features and advantages of the invention will be apparent from the description and drawings, and from the claims.
DESCRIPTION OF DRAWINGS
[0027] [0027]FIG. 1 is a schematic perspective view of a portion of a foam bun.
[0028] [0028]FIG. 2 is a highly enlarged cross-sectional view of a portion of the foam bun, taken along line A-A in FIG. 1, showing a prior art fastening system.
[0029] [0029]FIG. 3 is a highly enlarged cross-sectional view of the same area of the bun, also taken along line A-A in FIG. 1, in which the prior art fastening system is replaced by a fastening system according to one embodiment of the invention.
[0030] [0030]FIG. 3A is a cross-sectional view of the entire bun, taken along line 3 A- 3 A in FIG. 1.
[0031] [0031]FIG. 4 is an enlarged cross-sectional view showing a mold for the foam bun of FIG. 1.
[0032] [0032]FIG. 4A is similar to FIG. 4, but shows the mold after foam has been delivered to the mold cavity.
[0033] [0033]FIG. 5 is an enlarged detail view of the portion of the seat cushion shown in FIG. 2.
[0034] [0034]FIG. 6 is an enlarged detail view of the portion of the seat cushion shown in FIG. 3.
[0035] [0035]FIG. 7 is an enlarged cross-sectional view showing an alternate embodiment of the invention.
[0036] [0036]FIG. 7A is an enlarged cross-sectional view showing an alternate embodiment of the invention.
[0037] [0037]FIG. 8 is an enlarged cross-sectional view showing an alternate embodiment of the invention.
DETAILED DESCRIPTION
[0038] As discussed above, FIG. 1 shows a foam bun 10 with trenches 18 in which a fastener strip 24 is positioned for attachment of a fabric cover. As discussed above and shown in FIG. 2, it is well known to position the attachment strip in a flat-bottomed trench.
[0039] In the embodiment shown in FIGS. 3 and 3A, the flat-bottomed trenches 18 , shown in FIG. 2, are replaced by trenches 118 having an inclined bottom surface 117 . Inclined bottom surface 117 is disposed at an angle A relative to a plane P that is generally parallel to the planar surface of central portion 12 and perpendicular to the centerline CL of the seat. Typically, angle A is from about 10 to 80 degrees, preferably about 30 to 60 degrees. A suitable angle for a given application can be selected based on the degree of curvature of the trench and the narrowness of the trench desired.
[0040] Generally, as angle A increases, the trench may define curves with decreasing radii of curvature which results in increasing deformation of the ends of the fastener strip either up or down. However, as the radius of curvature decreases, the free ends of the strip will tend to bend downward and the center of the strip will tend to rise (or vice versa, depending on the configuration of the slope), preventing the entire length of the strip from seating properly in the trench. Thus, it is generally preferable that the radius of curvature of the trench be greater than about 15 inches. Lesser radii of curvature may be used, however it may be necessary to piece together two or more sections of fastener strip to accommodate such curves.
[0041] As shown in FIGS. 3 and 3A, the incline of the slope of the bottom surface 117 of the trench 118 can be defined by the angle A where such angle is measured from a plane P which is perpendicular to the centerline CL of the seat, where plane P is generally parallel to the in-car position of the occupant and which is generally flat to the central portion 12 of the seat.
[0042] The relative dimensions of the flat-bottomed and inclined trenches are shown in FIGS. 5 and 6. As shown in FIG. 5, typically a prior art flat-bottomed trench will have a width W1 of from about 0.75 to 1.25 inches, e.g., less than 1.0 inch, and a depth D1 of from about 0.0 inches to 2.0 inches. Widths W1 and W2 are defined as the horizontal distance between opposing side edges of the fastening strip. Optional trenches 47 are shown disposed on either side of fastening strip 24 . Depths D1 and D2 will vary based on the style of the seat, and are defined as the vertical distance between the surface 33 of central portion 12 and the centerline of the fastening strip 24 .
[0043] As discussed above, due to the slope of the bottom surface of the trench, the width W2 of the trench is generally less than W1, e.g., at least 10% less. Thus, W2 is preferably less than 1 inches, typically about {fraction (5/8 )} to {fraction (3/4)} inches These widths correspond to a fastener strip having an overall width of generally less than about 1 inch, typically from about {fraction (5/8 )} to {fraction (3/4)} inches, with a hook-carrying width of from about {fraction (1/2 )} to {fraction (5/8)} inches.
[0044] A suitable process for insert molding a foam bun onto a fastener strip is described in U.S. Pat. No. 5,945,193 to Pollard, entitled TOUCH FASTENER WITH POROUS METAL CONTAINING LAYER, the entire disclosure of which is incorporated herein by reference.
[0045] To form the molded bun 10 , touch fastener strip 24 is placed in mold 52 , as shown in FIG. 4. The touch fastener strip 24 contains a magnetically-attractable component (not shown), e.g. a metal shim bonded between one or more layers of the fastener strip, or a ferrous metal filler incorporated in the fastener strip. The magnetically attractable component holds the touch fastener strip 24 securely in the mold, due to magnetic attraction to a magnet (not shown) in the mold. The touch fastener strip also includes loops 44 , on the non-hook-carrying side 50 of the strip.
[0046] As shown in FIGS. 4 and 4A, the hook-carrying side 48 of touch fastener strip 24 is placed in a fastener element-receiving mold valley 42 of mold 52 , with the non-hook-carrying side 50 of touch fastener strip 24 facing into the mold cavity 46 . Referring to FIG. 4A, foam 56 , e.g. a molten polyurethane, is delivered to the mold cavity 46 , where the foam 56 comes into contact with side 50 of the touch fastener strip 24 . The foam 56 bonds to side 50 , embedding loops 44 in foam, thereby bonding touch fastener strip 24 to the foam bun.
[0047] As is known in the art, several features may be provided to protect the hooks from being contaminated with foam. To prevent foam 56 from entering mold valley 42 , mold valley 42 is generally narrower than the width of the touch fastener strip 24 , so that the edges of touch fastener strip 24 extend beyond the sides of the mold valley 42 . Also, mold valley 42 may include ridges 43 , corresponding to channels 47 in FIGS. 3 and 6, to inhibit flow of foam around the edges of the fastener strip 24 . Additionally, as described in U.S. Pat. No. 4,693,921, the complete disclosure of which is incorporated herein by reference, a removable protective barrier (not shown) may be placed over the hooks of hook-carrying side 48 of touch fastener strip 24 , prior to placing touch fastener strip 24 into mold 52 .
[0048] Suitable fastener strips are described, e.g., in U.S. Pat. Nos. 5,996,189, 6,066,281 and 6,129,970, the complete disclosures of which are incorporated herein by reference. U.S. Pat. No. 5,996,189 to Wang, entitled WOVEN FASTENER PRODUCT, describes touch fastener products formed by weaving methods. U.S. Pat. No. 6,066,281 to Provost, entitled FASTENER PRODUCTS AND THEIR PRODUCTION, describes touch fastener products formed by extruding molten polymer through an extrusion die. U.S. Pat. No. 6,129,970 to Kenney et al., entitled TOUCH FASTENER WITH MAGNETIC ATTRACTANT AND MOLDED ARTICLE CONTAINING SAME, describes incorporation of a magnetic attractant to touch fastener products. Touch fastener elements may also be formed by molding the stems and post-forming the end of the stems to form the fastener heads. Extruded touch fastener products may also be formed by extruding with fastening element rails, then cutting and stretching the element rails.
[0049] Other embodiments are within the scope of the following claims.
[0050] For example, the touch fastener strip may be positioned on an inclined surface other than the bottom surface of the trench. Thus, as shown in FIG. 7, touch fastener strip 24 may be placed on inclined surface 84 of bolster 16 . In this embodiment, the bottom surface of trench 18 may be flat (as shown) or inclined (as in FIG. 7A). The inclined surface is disposed at an angle A 1 with respect to the generally planar surface of the central portion 12 and perpendicular to centerline CL that is preferably approximately the same as angle A discussed above. Similarly, as shown in FIG. 8, touch fastener strip 24 may be located on inclined surface 84 of side bolster 16 and the trench between bolster 16 and central portion 12 of seat cushion 10 can be omitted entirely In this embodiment touch fastener strip 24 is not located below the surface 33 of central portion 12 of seat cushion 10 .
[0051] Moreover, while in the embodiments shown in FIGS. 2-8 a hook-carrying touch fastener strip is shown on the foam bun, and a cooperative loop-carrying touch fastener strip is shown on the fabric cover, alternatively the loop touch fastener may be positioned on the foam bun and the hook touch fastener may be attached to the upholstery.
[0052] Also, while hooks have been discussed above, other types of fastener elements may be used, e.g., mushroom heads or other male fastener. Male-to-male cooperative touch fastener elements may also be used. Preferably, the hooks are multi-directional, as shown. If the hooks include crooks that face in one direction only, it is generally preferred that the crooks face the bottom of the trench. However, the hooks can face in any desired direction provided that adequate engagement strength is obtained.
[0053] Moreover, while the touch fastener strip has been illustrated as spanning substantially the entire width of the trench, the touch fastener strip may be narrower than the trench.
[0054] The entire length of the bottom surface of the trench may be inclined, as described above, or, if desired, the trench may be relatively flat-bottomed in areas that are not curved, and the bottom surface inclined only in areas that are curved. The bottom surface of the trench or portions thereof may also be inclined in trenches that are not curved.
[0055] An example of a seat cushion design is shown in FIG. 1. However, it will be appreciated that the invention may be used in many other types of seat cushion designs, with trenches disposed in other areas and having other degrees of curvature.
[0056] Moreover, while the trenches shown in the figures and discussed above include a bottom and generally parallel side walls, the side wall between the trench bottom and the central portion may be omitted, in which case the inclined surface on which the fastener strip is disposed would be considered the bottom surface of the trench. | Seat cushions are provided including a foam bun, including a first, generally planar central region and a second, generally non-planar region, the first and second regions being separated by an elongated trench, and, disposed in the trench, an elongated touch fastener strip having a first surface that is bonded to the bottom of the trench and a second surface that carries a plurality of fastener elements. The trench has at least a portion of its bottom surface that is inclined with respect to a plane that is generally parallel to the planar central region, allowing the touch fastener strip to be extended around a curve in the trench without buckling. | 8 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] None.
STATEMENTS REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] None.
REFERENCE TO A MICROFICHE APPENDIX
[0003] None.
BACKGROUND OF THE INVENTION
[0004] 1. Field of the Invention
[0005] The present invention relates to hydraulic control systems for actuation of subsea equipment, particularly to a hydraulic control system and method for use in deep water with a subsea Blowout Preventer (BOP) stack, more particularly for a hydraulic control system and method utilizing a retrievable control pod for the actuation of subsea Blowout Preventer (BOP) stacks.
[0006] 2. Description of the Related Art
[0007] Offshore drilling for oil and natural gas from floating vessels is conventionally done through a drilling riser between the floating drilling vessel and a BOP stack located at the seabed.
[0008] The hydraulic functions of the BOP stack may be controlled by a hydraulic control system or an electro-hydraulic control system.
[0009] The first shallow-water subsea BOP control systems were discrete direct hydraulic control systems, in which hydraulic pressure is conveyed from the surface directly to a particular hydraulic actuator on the subsea BOP stack by way of a discrete hydraulic conduit.
[0010] Later subsea control systems were “piloted” discrete hydraulic control systems, in which hydraulic pilot signals are conveyed down a dedicated hydraulic conduit to a pilot valve, which directs hydraulic pressure from a subsea hydraulic manifold to a particular hydraulic actuator on the subsea BOP stack.
[0011] Other subsea control systems of this era included multifunction hydraulic systems which used various techniques to deliver more than one signal per hydraulic conduit; for example, coded hydraulic pulses, or a matrix of hydraulic signals, or sequenced signals at increasing pressures.
[0012] Still later control systems were “discrete” electro-hydraulic systems, with one electrical conductor per hydraulic function, or “multiplexed” (or “MUX”) systems, in which coded signals are transmitted via a small number of conductors.
[0013] Modern subsea control systems are almost exclusively MUX systems, which offer the advantages of ease of automation, rapid signal times between the surface and the seabed, and relatively easy retrievability of the control “pod”.
[0014] However, there are still scores of older hydraulic systems extant, particularly piloted hydraulic control systems which were originally designed to be used in conjunction with guideline-deployed subsea BOP stacks.
[0015] Referring now to FIG. 1 , which is a perspective view of a typical subsea BOP stack, Lower Marine Riser Package (LMRP) and associated hydraulic control system of the prior art. For clarity, the LMRP is shown unlatched from the BOP stack, as if it were, for example, being tripped back to the surface.
[0016] The Subsea BOP stack 100 has stack framework 101 which supports the subsea BOP stack and also serves to guide the stack from the surface to the seabed along guidelines 102 . Subsea BOP stack 100 also has lower female hydraulic receptacles 103 A and 103 B with fluid passages 104 which are hydraulically connected to BOP control lines 105 .
[0017] Lower Marine Riser Package (LMRP) 106 forms an upper, separable part of the Subsea BOP stack, and generally comprises at least one annular BOP 106 A, drilling riser 106 B with attached choke & kill lines 106 C, a flexible riser joint 106 D, an LMRP latch 107 between the LMRP 106 and the subsea BOP stack 100 , control pods 108 A and 108 B and a plurality of guideline funnels 109 guiding the LMRP along guidelines 102 . LMRP 106 also comprises upper female hydraulic receptacles 110 A and 110 B.
[0018] Generally, guideline funnels 109 are diametrically opposed on opposite sides of the LMRP. (Note that the opposing guideline funnel is not shown in FIG. 1 .) Control pods 108 A and 108 B may also fitted with their own, similar guideline funnels so that they may be retrieved separately from the LMRP.
[0019] Conventionally, control pods 108 A and 108 B are painted yellow and blue respectively, as those colors can be easily distinguished subsea by a closed-circuit television camera on a subsea remotely-operated vehicle (ROV).
[0020] Control pods 108 A and 108 B have control pod deployment cables 111 A and 111 B, and control pod umbilical 112 A and 112 B. Conventionally, control pod umbilicals 112 A and 112 B are clamped (not shown) to control pod deployment cables 111 A and 111 B with, for example, clamps of the types taught in U.S. Pat. Nos. 4,445,255 to Olejak, and 4,437,791 to Reynolds.
[0021] Control pods 108 A and 108 B also have latching mechanism 113 A and 113 B (latching mechanism 113 B is not visible) on male members 114 A and 114 B male member 114 B is not visible) which latch the control pods into upper female control receptacles 110 A and 110 B. Control pods 108 A and 108 B also have male hydraulic connectors 115 A and 115 B (not visible) which mate with upper female control receptacles 110 A and 110 B.
[0022] Referring now to FIG. 2 , which is a perspective view of a control pod and its associated female hydraulic receptacles. Control pod 200 has control pod deployment cable 201 , control pod umbilical 202 , male member 203 with latching mechanism 204 , and male hydraulic connector 205 with frustoconical surface 205 A and a plurality of hydraulic ports 206 .
[0023] Control pod 200 also has junction plate 202 A (commonly called a “kidney plate”) deposed between control umbilical 202 and control pod 200 which provides hydraulic connections between the umbilical and the hydraulic piping and vavling within the pod.
[0024] LMRP 207 has upper female hydraulic receptacle 210 , which has a plurality of inner hydraulic ports 209 , inner frustoconical surface 209 A, a plurality of outer hydraulic ports 210 , and outer frustoconical surface 210 A.
[0025] Subsea stack 211 has lower female hydraulic receptacle 212 with a plurality of inner hydraulic ports 214 , inner frustoconical surface 214 A, and spring mounts 213 .\
[0026] When control pod 200 is latched into LMRP 207 by latching mechanism 204 , frustoconical surface 205 A on male hydraulic connector 205 mates with frustoconical surface 209 A on upper female hydraulic receptacle 208 .
[0027] When LMRP is latched to subsea stack 211 by LMRP latch 107 (in FIG. 1 ), frustoconical surface 210 A on upper female hydraulic receptacle 208 mates with frustoconical surface 214 A on lower female hydraulic receptacle 212 .
[0028] For LMRP hydraulic control functions such as annular BOP 106 A or LMRP latch 107 (both in FIG. 1 ), hydraulic pressure is supplied by control pod 200 to a hydraulic port 206 on the male hydraulic connector 205 , which is hydraulically mated to an inner hydraulic port 209 on the upper female hydraulic receptacle 208 , and routed to a control hose (not shown) leading to the particular LMRP control function.
[0029] For hydraulic functions in the BOP stack 211 , such as opening or closing of a ram-type BOP, hydraulic pressure is supplied by control pod 200 to a hydraulic port 206 on male hydraulic connector 205 , which is hydraulically mated to an inner hydraulic port 209 on the upper female hydraulic receptacle 208 , which in turn is hydraulically connected to an outer hydraulic port 210 which mates hydraulically with inner hydraulic port 214 on lower female hydraulic receptacle 212 . Inner hydraulic port 214 is in turn connected hydraulically to a BOP control hose 105 (shown in FIG. 1 ) leading to a particular BOP stack control function.
[0030] Subsea control well systems for hydraulically controlling subsea well equipment are generally shown in U.S. Pat. Nos. 3,460,614 and 3,701,549, which are incorporated by reference in their entirety.
[0031] As drilling water depths got much deeper throughout the 1990's, offshore drillers initially abandoned the use of guidelines to deploy and retrieve BOP stacks, and instead tripped the BOP stack “guidelineless,” often with the aid of ROVs. They also discovered that the currents in deep water could cause severe and deleterious “vortex-induced vibration” (“VIV”) in the control pod deployment cable 201 and the control pod umbilical 202 clamped to it, often severely damaging the expensive umbilical. Consequently, most drillers have abandoned the control pod deployment cable 201 on subsea BOP stacks run in deep water, and today run the control pod umbilical 202 attached the drilling riser 106 B (in FIG. 1 ), usually clamped to the choke & kill lines 106 C.
[0032] However, with the control pod umbilical attached to the riser, a control pod may be retrieved for inspection and repair only by tripping the entire LMRP with both pods attached, which is extremely expensive and time consuming. It would be advantageous to be able to retrieve one control pod at a time, without tripping the entire riser and LMRP, but to continue to run the umbilical attached to the riser to avoid deleterious VIV.
[0033] Some prior art systems sought to address this issue. One prior art system, for example, taught in U.S. Pat. No. 4,328,826 to Baugh, et al, features flat, vertically stacked flat connector plates which allow the control pod to connect to the control umbilical through a connector plate, which in turn allows the control pod to be fully retrievable. However, this and other prior art systems all require that the existing control pods with frustoconical hydraulic receptacles be replaced, at very high cost. It would therefore be advantageous to be able to inexpensively modify an existing hydraulic control system comprising a riser-mounted umbilical such that the existing hydraulic control pod is retrievable independent of the LMRP, the riser, and the other control pod.
[0034] Further, it would be advantageous if such a modification for an existing hydraulic control system could be easily retrofitted to the LMRP structure, and if it were sufficiently compact to fit within the confines of the existing equipment in the LMRP, which may, in some cases, require the modification to “wrap around” the other equipment.
[0035] Still further, the junction plate 202 A is a complicated, heavy, and expensive machined part in which multiple hydraulic seals reside; although these seals are usually robust, the junction plate arrangement has the potential for multiple leak-paths between the umbilical and the control pod. It would therefore be advantageous to eliminate the junction plate 202 A as an interface between the pod and the umbilical.
BRIEF SUMMARY OF THE INVENTION
[0036] The present invention is directed to hydraulic subsea control system for a subsea BOP stack comprising a retrievable hydraulic control pod with hydraulic receptacles, and an umbilical attached to the drilling riser. The hydraulic control system of the present invention comprising a subsea hydraulic umbilical line, a lower marine riser package having a hydraulic receptacle, a hydraulic control pod having a hydraulic connector for hydraulically mating with the hydraulic receptacle, at least one pod umbilical hydraulic connector hydraulically connected through umbilical connector piping to said hydraulic control pod, and at least one lower marine riser package umbilical hydraulic connector for hydraulically mating with said pod umbilical hydraulic connector and said subsea hydraulic umbilical line. When the system of the present invention is operated, a hydraulic flow path exists allowing hydraulic fluid to flow from the subsea hydraulic umbilical line through the lower marine riser package umbilical hydraulic connector through the pod umbilical hydraulic connector and into the hydraulic control pod which is hydraulically connected to the lower marine riser package hydraulic receptacle.
[0037] In one aspect, the invention relates to a hydraulic control pod with a male frustoconical hydraulic connector, adapted to be retrieved from a subsea BOP stack while the umbilical control hose remains attached to the drilling riser.
[0038] In another aspect, the invention relates to a method for converting a hydraulic control system to allow the subsea control pod to be retrieved while the umbilical control hose remains attached to the drilling riser.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0039] A better understanding of the present invention can be obtained when the following detailed description of the disclosed embodiments is considered in conjunction with the following drawings, in which:
[0040] FIG. 1 is a perspective view of a subsea stack and Lower Marine Riser Package (LMRP) of the prior art.
[0041] FIG. 2 is a perspective view of an hydraulic control pod and associated female hydraulic receptacles on the LMRP and the subsea BOP stack, all of the prior art.
[0042] FIG. 3 is a section view of a preferred embodiment of the hydraulic control system of the present invention.
[0043] FIG. 3A is a section view of the preferred hydraulic control system shown in FIG. 3 , at “A-A” in FIG. 3 .
[0044] FIG. 3B is a section view of the preferred hydraulic control system shown in FIG. 3 , in the landed and latched position.
[0045] FIG. 4A is a chart of hydraulic flows in a hydraulic control system of the prior art.
[0046] FIG. 4B is a chart of hydraulic flows of the preferred embodiment of the hydraulic control system of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0047] Refer now to FIG. 3 , which shows a preferred embodiment of the present invention. Control pod 300 has umbilical junction plate 300 A, male member 301 with latching mechanism 302 , male hydraulic connector 303 with frustoconical surface 303 A, and control pod deployment cable attachment point 304 .
[0048] Control pod 300 also has radial connector brackets 305 A and 305 B, with attached pod umbilical connectors 306 A and 306 B, which have hydraulic ports 306 C.
[0049] Pod umbilical connectors 306 A and 306 B are hydraulically connected to the valving inside the control pod 300 by umbilical connector piping 306 D. As shown, umbilical connector piping 306 D by-passes umbilical junction plate 300 A; in this embodiment, umbilical junction plate 300 A may be eliminated in order to save weight in control pod 300 .
[0050] Alternately, umbilical junction plate 300 A may be retained, and umbilical connector piping 306 D may be run from pod umbilical connectors 306 A and 306 B to the hydraulic connectors on the top of umbilical junction plate 300 A. Since the internal piping inside control pod 300 A is often complex and convoluted, this approach may save time and money during a conversion. Furthermore, there may be circumstances when it is advantageous to retain umbilical junction plate 300 A despite its added weight; for example, for a spare pod which a driller may wish to configure for either shallow water drilling (with umbical run separately from the riser) or for deepwater drilling (with the umbilical attached to the riser).
[0051] LMRP 307 has LMRP umbilical connectors 308 A and 308 B, attached to LMRP 307 by compliant suspension 309 and mounting brackets 310 . The complaint suspension 309 as shown comprises coil springs and spherical bearings mounted between LMRP umbilical connectors 308 A and 308 B and corresponding mounting brackets 310 , which allows LMRP umbilical connectors 308 A and 308 B to move about slightly when they are mated with pod umbilical connectors 306 A and 306 B. However, those skilled in the art will recognize that other mechanisms, such as elastomeric springs, Belleville washers, or hydraulic spring elements may be utilized without departing from the spirit of the invention.
[0052] LMRP umbilical connectors 308 A and 308 B are hydraulically connected to umbilical hoses 308 C. Ideally, the umbilical hose may be configured such that the individual hoses within the umbilical bundle may be connected directly to LMRP umbilical connectors 308 A and 308 B without intervening hydraulic connections. In some circumstances, of course, the umbilical may have to be terminated on or near the riser, and jumper hoses (for example) used to connect the umbilical to the LMRP umbilical connectors.
[0053] LMRP 307 also has upper female hydraulic receptacle 311 , which has inner hydraulic ports 312 and outer hydraulic ports 313 (not visible in this sectional view), inner frustoconical surface 312 A, and outer frustoconical surface 313 A.
[0054] Subsea BOP stack 314 has lower female hydraulic receptacle 315 with inner frustoconical surface 315 A, and inner hydraulic ports 316 (not visible in this section view).
[0055] In the embodiment shown in FIG. 3 , pod umbilical connectors 306 A and 306 B are male wedge-type connectors and LMRP umbilical connectors 308 A and 308 B. are mating female wedge-type connectors. In another embodiment, pod umbilical connectors 306 A and 306 B are female wedge-type connectors and LMRP umbilical connectors 308 A and 308 B are mating male wedge-type connectors. In still another embodiment, pod umbilical connectors 306 A and 306 B and LMRP umbilical connectors 308 A and 308 B are frustoconical type connectors, essentially versions of the hydraulic connectors beneath the control pod. Those skilled in the art will appreciate that the mating pod umbilical connectors and LMRP umbilical connectors may be any of many types of subsea wet-mateable hydraulic connectors known in the art.
[0056] Further, in the embodiment of the instant invention shown in FIG. 3 , the control pod 300 is generally cylindrical in shape. Those skilled in the art will recognize that the control pod may be rectangular or another shape, and still be mated to a frustoconical male hydraulic connector 303 .
[0057] In one embodiment of the instant invention, there are two radial connector brackets attached to the control pod. In another embodiment, there are more than two radial connector brackets.
[0058] In another embodiment of the instant invention, there are two radial connector brackets with associated pod umbilical connectors; one pod umbilical connector contains hydraulic circuits for LMRP controls and the other contains hydraulic circuits for the subsea BOP.
[0059] In yet another embodiment of the instant invention, there is only one radial connector bracket with an associated pod umbilical connector. In a related embodiment, the one radial connector bracket is arranged radially away from the well center.
[0060] Refer now to FIG. 3A , which shows a horizontal section through the pod (at “A-A” in FIG. 3 ). Control pod 300 has radial connector brackets 305 A and 305 B, with attached pod umbilical connectors 306 A and 306 B. In this embodiment, radial connector brackets 305 A and 305 B are substantially horizontally opposed on opposite sides of control pod 300 (that is, the inner included angle 319 between the brackets is 180 degrees), and a vertical plane 316 through radial connector brackets 305 A and 305 B is substantially tangential to well center axis 317 (which is coincident with the center of the riser 106 B and the annular BOP 106 A in FIG. 1 ).
[0061] In another embodiment of the instant invention, radial connector brackets 318 A and 318 B are each substantially tangential to well center axis 317 .
[0062] In another embodiment which may provide the most compact installation, radial connector brackets 318 A and 318 B are each substantially tangential to well center axis 317 , and the inner included angle ( 319 in FIG. 3A ) between the brackets is minimized.
[0063] For a well center-to-pod center distance D ( 320 in FIG. 3A ) and overall radial bracket length “L” ( 321 in FIG. 3A ), a minimum inner included angle α is defined by the following equation: Equation 1 α=2(arc cos D/L)
[0064] In another embodiment of the instant invention, the included angle between the radial connector brackets will be between about 180 degrees and minimum inner included angle α as calculated by Equation 1.
[0065] Another embodiment of the instant invention consists of a method to convert an existing hydraulic control system to a system with retrievable control pods and an umbilical attached to the riser, comprising the steps of affixing one or more radial connector brackets and associated pod umbilical connector to the control pod, affixing mating LMRP umbilical connector and associated compliant suspension and mounting bracket to the LMRP, and plumbing the umbilical and control pod to the respective umbilical connectors.
[0066] Another embodiment of the method to convert an existing hydraulic control system further comprises the step of hydraulically by-passing the umbilical junction plate, and connecting the LMRP umbilical connectors directly to the valving within the control pod. In a related embodiment, the hydraulically by-passed umbilical junction plate may be permanently removed from the control pod in order to lower the weight of the pod, for example, for use in deep water.
[0067] In another embodiment, the method to convert an existing hydraulic control system comprises hydraulically connecting the individual hoses within the umbilical bundle directly to the LMRP umbilical connectors.
[0068] Generally, the most compact embodiment of the instant invention is preferred, for ease of retrofitting, compactness of the associated plumbing, and ease of subsea installation and retrieval. One such preferred embodiment comprises two pod connector brackets which are as short as practically possible (that is, with a small bracket length “L”), arrayed at the minimum interior angle α, and no junction plate 300 A (colloquially known as the “kidney plate” after its shape) or associated hydraulic piping and connections, in order to save weight in the control pod.
[0069] FIG. 3B shows the embodiment of the instant invention shown in FIG. 3 , with control pod 300 latched into LMRP 307 , and the LMRP 307 landed and latched to the BOP stack 314 . The umbilical hoses 308 C are hydraulically connected to LMRP connectors 308 A and 308 B. LMRP connectors 308 A and 308 B are hydraulically connected to pod connectors 306 A and 306 B respectively. Pod connectors 306 A and 306 B are hydraulically connected directly to the valving in control pod 300 with umbilical connector piping 308 C.
[0070] An existing hydraulic control pod may, according to the teachings of this disclosure, be modified to allow the control pod to be retrieved from the LMRP installed on the subsea stack without tripping the drilling riser and the attached umbilical control lines. In one embodiment, the method to convert an existing control pod may comprise the steps of attaching radial connector arms with hydraulic connectors to the control pod, attaching mating hydraulic connectors to the LMRP, and plumbing the umbilical hose bundle and the subsea control pod functions to the hydraulic connectors. In another embodiment, the method to modify a hydraulic control pod may comprise attaching the radial control arms at an inner included angle of between 180 degrees and the minimum inner included angle.
[0071] FIG. 4A shows hydraulic flows in hydraulic control systems of the prior art. Fluid from the umbilical 400 flows directly to the control pod 401 . Upon a signal to actuate a function in the LMRP (such as opening or closing the annular BOP), fluid flows from the control pod 401 through the upper female connector 402 to the selected LMRP function 403 . Upon a signal to actuate a function in the subsea BOP stack (such as opening or closing a ram BOP), fluid flows from the control pod 401 through the upper female connector 402 and the lower female connector 404 to the selected BOP stack function 405 .
[0072] FIG. 4B shows the hydraulic flow paths in a hydraulic control system which is an embodiment of the instant invention. Fluid from the umbilical 400 flows to an LMRP connector 406 and a corresponding pod connector 407 to the control pod 407 . Upon a signal to actuate a function in the LMRP (such as opening or closing the annular BOP), fluid flows from the control pod 401 through the upper female connector 402 to the selected LMRP function 403 . Upon a signal to actuate a function in the subsea BOP stack (such as opening or closing a ram BOP), fluid flows from the control pod 401 through the upper female connector 402 and the lower female connector 404 to the selected BOP stack function 405 .
[0073] In view of this disclosure, various other modifications may be made to the hydraulic control system of the instant invention by those of ordinary skill in the art without departing from the spirit of the invention. It should be understood, therefore, that the instant invention is not limited to the disclosed embodiments, but that the scope of the invention includes all embodiments within the following claims. | Systems and methods for improved hydraulic control systems for actuation of subsea equipment in deep water are disclosed. The hydraulic control system relies on smaller fluid flow associated with a hydraulic pressure pulse to actuate the small volume actuation control valve. In one embodiment, the system includes small diameter control umbilical hoses and pilot-operated valves with low actuation volumes. Particularly, a hydraulic control system for reducing the signal time to a subsea blowout preventer in water depth up to and greater than about 5000 feet. Some embodiments comprise a valve arrangement which hydraulically actuate one side of a hydraulic control function, while simultaneously evacuating the opposing circuit both at the seabed and at the surface. Some embodiments comprise an umbilical hose located proximate the center of an umbilical bundle. Preferably, the umbilical hose has a plurality of layers of reinforcing fibers which increase with the diameter of the reinforcement layer. | 4 |
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This patent application is a continuation of 10/346,828, filed Jan. 16, 2003, which is a continuation in part of Ser. No. 09/882,720, filed Jun. 14, 2001.
FIELD OF THE INVENTION
[0002] The present invention relates to EP 4 agonists, for example 3, 7 or 3 and 7 thia or oxa prostanoic acid derivatives as potent ocular hypotensives that are particularly suited for the management of glaucoma.
[0003] 1. Background of the Invention
[0004] 2. Description of Related Art
[0005] Ocular hypotensive agents are useful in the treatment of a number of various ocular hypertensive conditions, such as post-surgical and post-laser trabeculectomy ocular hypertensive episodes, glaucoma, and as presurgical adjuncts.
[0006] Glaucoma is a disease of the eye characterized by increased intraocular pressure. On the basis of its etiology, glaucoma has been classified as primary or secondary. For example, primary glaucoma in adults (congenital glaucoma) may be either open-angle or acute or chronic angle-closure. Secondary glaucoma results from pre-existing ocular diseases such as uveitis, intraocular tumor or an enlarged cataract.
[0007] The underlying causes of primary glaucoma are not yet known. The increased intraocular tension is due to the obstruction of aqueous humor outflow. In chronic open-angle glaucoma, the anterior chamber and its anatomic structures appear normal, but drainage of the aqueous humor is impeded. In acute or chronic angle-closure glaucoma, the anterior chamber is shallow, the filtration angle is narrowed, and the iris may obstruct the trabecular meshwork at the entrance of the canal of Schlemm. Dilation of the pupil may push the root of the iris forward against the angle, and may produce pupilary block and thus precipitate an acute attack. Eyes with narrow anterior chamber angles are predisposed to acute angle-closure glaucoma attacks of various degrees of severity.
[0008] Secondary glaucoma is caused by any interference with the flow of aqueous humor from the posterior chamber into the anterior chamber and subsequently, into the canal of Schlemm. Inflammatory disease of the anterior segment may prevent aqueous escape by causing complete posterior synechia in iris bombe, and may plug the drainage channel with exudates. Other common causes are intraocular tumors, enlarged cataracts, central retinal vein occlusion, trauma to the eye, operative procedures and intraocular hemorrhage.
[0009] Considering all types together, glaucoma occurs in about 2% of all persons over the age of 40 and may be asymptotic for years before progressing to rapid loss of vision. In cases where surgery is not indicated, topical b-adrenoreceptor antagonists have traditionally been the drugs of choice for treating glaucoma.
[0010] Certain eicosanoids and their derivatives have been reported to possess ocular hypotensive activity, and have been recommended for use in glaucoma management. Eicosanoids and derivatives include numerous biologically important compounds such as prostaglandins and their derivatives. Prostaglandins can be described as derivatives of prostanoic acid which have the following structural formula:
[0011] Various types of prostaglandins are known, depending on the structure and substituents carried on the alicyclic ring of the prostanoic acid skeleton. Further classification is based on the number of unsaturated bonds in the side chain indicated by numerical subscripts after the generic type of prostaglandin [e.g. prostaglandin E 1 (PGE 1 ), prostaglandin E 2 (PGE 2 )], and on the configuration of the substituents on the alicyclic ring indicated by α or β e.g. prostaglandin F 2α (PGF 2β )].
[0012] Prostaglandins were earlier regarded as potent ocular hypertensives, however, evidence accumulated in the last decade shows that some prostaglandins are highly effective ocular hypotensive agents, and are ideally suited for the long-term medical management of glaucoma (see, for example, Bito, L. Z. Biological Protection with Prostaglandins , Cohen, M. M., ed., Boca Raton, Fla, CRC Press Inc., 1985, pp. 231-252; and Bito, L. Z., Applied Pharmacology in the Medical Treatment of Glaucomas Drance, S. M. and Neufeld, A. H. eds., New York, Grune & Stratton, 1984, pp. 477505. Such prostaglandins include PGF 2α PGF 1α , PGE 2 , and certain lipid-soluble esters, such as C 1 to C 2 alkyl esters, e.g. 1-isopropyl ester, of such compounds.
[0013] Although the precise mechanism is not yet known experimental results indicate that the prostaglandin-induced reduction in intraocular pressure results from increased uveoscleral outflow [Nilsson et.al., Invest. Ophthalmol. Vis. Sci . (suppl), 284 (1987)].
[0014] The isopropyl ester of PGF 2β has been shown to have significantly greater hypotensive potency than the parent compound, presumably as a result of its more effective penetration through the cornea. In 1987, this compound was described as “the most potent ocular hypotensive agent ever reported” [see, for example, Bito, L. Z., Arch. Ophthalmol. 105, 1036 (1987), and Siebold et.al., Prodrug 5 3 (1989)].
[0015] Whereas prostaglandins appear to be devoid of significant intraocular side effects, ocular surface (conjunctival) hyperemia and foreign-body sensation have been consistently associated with the topical ocular use of such compounds, in particular PGF 2α and its prodrugs, e.g., its 1-isopropyl ester, in humans. The clinical potentials of prostaglandins in the management of conditions associated with increased ocular pressure, e.g. glaucoma are greatly limited by these side effects.
[0016] In a series of co-pending United States patent applications assigned to Allergan, Inc. prostaglandin esters with increased ocular hypotensive activity accompanied with no or substantially reduced side-effects are disclosed. The co-pending USSN 596,430 (filed Oct. 10, 1990, now U.S. Pat. No. 5,446,041), relates to certain 11-acyl-prostaglandins, such as 11-pivaloyl, 11-acetyl, 11-isobutyryl, 11-valeryl, and 11-isovaleryl PGF 2α . Intraocular pressure reducing 15-acyl prostaglandins are disclosed in the co-pending application USSN 175,476 (filed Dec. 29, 1993). Similarly, 11,15-9,15 and 9,11-diesters of prostaglandins, for example 11,15-dipivaloyl PGF 2α are known to have ocular hypotensive activity. See the co-pending patent applications USSN Nos. 385,645 (filed Jul. 7, 1989, now U.S. Pat. No. 4,994,274), 584,370 (filed Sep. 18, 1990, now U.S. Pat. No. 5,028,624) and 585,284 (filed Sep. 18, 1990, now U.S. Pat. No. 5,034,413). The disclosures of all of these patent applications are hereby expressly incorporated by reference.
SUMMARY OF THE INVENTION
[0017] The present invention concerns a method of treating ocular hypertension which comprises administering to a mammal having ocular hypertension a therapeutically effective amount of an EP 4 agonist, e.g. a compound of formula I
[0018] wherein hatched lines represent the a configuration, a triangle represents the β configuration, a wavy line represents either the α configuration or the β configuration and a dotted line represents the presence or absence of a double bond;
[0019] A and B are independently selected from the group consisting of O, S and CH 2 ; provided that at least one of A or B is S;
[0020] D represents a covalent bond or CH 2 , O, S or NH;
[0021] X is CO 2 R, CONR 2 , CH 2 OR, P(O)(OR) 2 , CONRSO 2 R, SONR 2 or
[0022] Y is O, OH, OCOR 2 , halogen or cyano;
[0023] Z is CH 2 or a covalent bond;
[0024] R is H or R 2 ;
[0025] R is H, R 2 ,phenyl, or COR 2 ;
[0026] R 2 is C 1 -C 5 lower alkyl or alkenyl;
[0027] R 3 is benzothienyl, benzofuranyl, naphthyl, or substituted derivatives thereof, wherein the substituents maybe selected from the group consisting of C 1 -C 5 alkyl, halogen, CF 3 , CN, NO 2 , NR 2 , CO 2 R and OR; and
[0028] R 4 is hydrogen or C 1 -C 5 alkyl.
[0029] In a still further aspect, the present invention relates to a pharmaceutical product, comprising
[0030] a container adapted to dispense its contents in a metered form; and
[0031] an ophthalmic solution therein, as hereinabove defined.
BRIEF DESCRIPTION OF THE DRAWING FIGURES
[0032] [0032]FIG. 1 is a schematic of the chemical synthesis of a certain intermediate for the compounds of the invention as disclosed in Examples 1 through 3.
[0033] [0033]FIG. 2 is a schematic of the chemical synthesis of certain compounds related to the compounds of the invention as disclosed in Examples 4 through 7.
DETAILED DESCRIPTION OF THE INVENTION
[0034] The present invention relates to the use of EP 4 agonists, e.g. 3, 7 and 3 and 7 thia or oxa prostanoic acid derivatives, as ocular hypotensives. The compounds used in accordance with the present invention are encompassed by the following structural formula I:
[0035] A preferred group of the compounds of the present invention includes compounds that have the following structural formula II:
[0036] Another preferred group includes compounds having the formula III:
[0037] In the above formulae, the substituents and symbols are as hereinabove defined.
[0038] In the above formulae:
[0039] Preferably A and B are both S.
[0040] Preferably D represents a covalent bond or is CH 2 ; more preferably D is CH 2 .
[0041] Preferably Z represents a covalent bond.
[0042] Preferably R is H.
[0043] Preferably R 1 is H.
[0044] Preferably R 4 is hydrogen or methyl, most preferably hydrogen.
[0045] Preferably Y=O.
[0046] Preferably X is CO 2 R and more preferably R is selected from the group consisting of H, methyl, i-propyl and n-propenyl.
[0047] The above compounds of the present invention may be prepared by methods that are known in the art or according to the working examples below. The compounds, below, are especially preferred representative, of the compounds of the present invention.
[0048] {3-[(1R,2S,3R)-3-Hydroxy-2-((S)-(E)-3-(hydroxy)-5-(naphthyl)pent-1-enyl)-5-oxocyclopentylsulfanyl]propylsulfanyl}acetic acid methyl ester,
[0049] {3-[(1R,2S,3R)-3-Hydroxy-2-((S)-(E)-3-(hydroxy)-5-(naphthyl)pent-1-enyl)-5-oxocyclopentylsulfanyl]propylsulfanyl}acetic acid,
[0050] {3-[(1R,2S,3R)-3-Hydroxy-2-((S)-(E)-3-(hydroxy)-5-(naphthyl)pent-1-enyl)-5-oxocyclopentylsulfanyl]propylsulfanyl}acetic acid isopropyl ester,
[0051] {3-[(1R,2S,3R)-3-Hydroxy-2-((S)-(E)-3-hydroxy-5-(benzothienyl)pent-1-enyl)-5-oxocyclopentylsulfanyl]propylsulfanyl}acetic acid methyl ester,
[0052] {3-[(1R,2S,3R)-3-Hydroxy-2-((S)-(E)-3-hydroxy-5-(benzothienyl)pent-O-enyl)-5-oxocyclopentylsulfanyl]propylsulfanyl}acetic acid,
[0053] {3-[(1R,2S,3R)-3-Hydroxy-2-((S)-(E)-3-hydroxy-5-(benzothienyl)pent-1-enyl)-5-oxocyclopentylsulfanyl]propylsulfanyl}acetic acid isopropyl ester,
[0054] {3-[(1R,2S,3R)-3-Hydroxy-2-((S)-(E)-3-hydroxy-5-(benzofuranyl)pent-1-enyl)-5-oxocyclopentylsulfanyl]propylsulfanyl}acetic acid methyl ester,
[0055] {3-[(1R,2S,3R)-3-Hydroxy-2-((S)-(E)-3-hydroxy-5-(benzofuranyl)pent-1-enyl)-5-oxocydopentylsulfanyl]propylsulfanyl}acetic acid,
[0056] {3-[(1R,2S,3R)-3-Hydroxy-2-((S)-(E)-3-hydroxy-5-(benzofuranyl)pent-1-enyl)-5-oxocyclopentylsulfanyl]propylsulfanyl}acetic acid isopropyl ester,
[0057] {3-[(1R,2S,3R)-3-Hydroxy-2-((E)-3-hydroxy-4-naphthalen-2-yl-but-1-enyl)-5-oxocyclopentylsulfanyl]propylsulfanyl}acetic acid methyl ester,
[0058] {3-[(1R,2S,3R)-3-Hydroxy-2-((E)-3-hydroxy-4-naphthalen-2-yl-but-1-enyl)-5-oxocyclopentylsulfanyl]propylsulfanyl}acetic acid,
[0059] {3-[(1R,2S,3R)-2-((E)-4-Benzo[b]thiophen-3-yl-3-hydroxybut-1-enyl)-3-hydroxy-5-oxocyclopentylsulfanyl]propylsulfanyl}acetic acid methyl ester,
[0060] {3-[(1R,2S,3R)-2-((E)-4-Benzo[b]thiophen-3-yl-3-hydroxybut-1-enyl)-3-hydroxy-5-oxocyclopentylsulfanyl]propylsulfanyl}acetic acid,
[0061] {3-[(1R,2S,3R)-3-Hydroxy-2-((S)-(E)-3-(hydroxy)-3-(methyl)-5-(naphthyl)pent-1-enyl)-5-oxocyclopentylsulfanyl]propylsulfanyl}acetic acid methyl ester,
[0062] {3-[(1R,2S,3R)-3-Hydroxy-2-((E)-3-hydroxy-3-methyl-4-naphthalen-2-yl-but-1-enyl)-5-oxocyclopentylsulfanyl]propylsulfanyl}acetic acid methyl ester,
[0063] {3-[(1R,2S,3R)-3-Hydroxy-2-((E)-3-hydroxy-3-methyl-4-naphthalen-2-yl-but-1-enyl)-5-oxocyclopentylsulfanyl]propylsulfanyl}acetic acid,
[0064] {3-[(1R,2S,3R)-3-Hydroxy-2-((S)-(E)-3-(hydroxy)-3-(methyl)-5-(naphthyl)but-1-enyl)-5-oxocyclopentylsulfanyl]propylsulfanyl}acetic acid,
[0065] {3-[(1R,2S,3R)-3-Hydroxy-2-((S)-(E)-3-(hydroxy)-3-(methyl)-5(benzothienyl)pent-1-enyl)-5-oxocyclopentylsulfanyl]propylsulfanyl}acetic acid methyl ester and
[0066] {3-[(1R,2S,3R)-3-Hydroxy-2-((S)-(E)-3-(hydroxy)-3-(methyl)-5(benzothienyl)pent-1-enyl)-5-oxocyclopentylsulfanyl]propylsulfanyl}acetic acid methyl ester.
[0067] Pharmaceutical compositions may be prepared by combining a therapeutically effective amount of at least one compound according to the present invention, or a pharmaceutically acceptable acid addition salt thereof, as an active ingredient, with conventional ophthalmically acceptable pharmaceutical excipients, and by preparation of unit dosage forms suitable for topical ocular use. The therapeutically efficient amount typically is between about 0.0001 and about 5% (w/v), preferably about 0.001 to about 1.0% (w/v) in liquid formulations.
[0068] For ophthalmic application, preferably solutions are prepared using a physiological saline solution as a major vehicle. The pH of such ophthalmic solutions should preferably be maintained between 6.5 and 7.2 with an appropriate buffer system. The formulations may also contain conventional, pharmaceutically acceptable preservatives, stabilizers and surfactants.
[0069] Preferred preservatives that may be used in the pharmaceutical compositions of the present invention include, but are not limited to, benzalkonium chloride, chlorobutanol, thimerosal, phenylmercuric acetate and phenylmercuric nitrate. A preferred surfactant is, for example, Tween 80. Likewise, various preferred vehicles may be used in the ophthalmic preparations of the present invention. These vehicles include, but are not limited to, polyvinyl alcohol, povidone, hydroxypropyl methyl cellulose, poloxamers, carboxymethyl cellulose, hydroxyethyl cellulose and purified water.
[0070] Tonicity adjustors may be added as needed or convenient. They include, but are not limited to, salts, particularly sodium chloride, potassium chloride, mannitol and glycerin, or any other suitable ophthalmically acceptable tonicity adjustor.
[0071] Various buffers and means for adjusting pH may be used so long as the resulting preparation is ophthalmically acceptable. Accordingly, buffers include acetate buffers, citrate buffers, phosphate buffers and borate buffers. Acids or bases may be used to adjust the pH of these formulations as needed.
[0072] In a similar vein, an ophthalmically acceptable antioxidant for use in the present invention includes, but is not limited to, sodium metabisulfite, sodium thiosulfate, acetylcysteine, butylated hydroxyanisole and butylated hydroxytoluene.
[0073] Other excipient components which may be included in the ophthalmic preparations are chelating agents. The preferred chelating agent is edentate disodium, although other chelating agents may also be used in place or in conjunction with it.
[0074] The ingredients are usually used in the following amounts:
Ingredient Amount (% w/v) active ingredient about 0.001-5 preservative 0-0.10 vehicle 0-40 tonicity adjustor 1-10 buffer 0.01-10 pH adjustor q.s. pH 4.5-7.5 antioxidant as needed surfactant as needed purified water as needed to make 100%
[0075] The actual dose of the active compounds of the present invention depends on the specific compound, and on the condition to be treated; the selection of the appropriate dose is well within the knowledge of the skilled artisan.
[0076] The ophthalmic formulations of the present invention are conveniently packaged in forms suitable for metered application, such as in containers equipped with a dropper, to facilitate the application to the eye. Containers suitable for dropwise application are usually made of suitable inert, non-toxic plastic material, and generally contain between about 0.5 and about 15 ml solution.
[0077] The invention is further illustrated by the following non-limiting Examples, which are summarized in the reaction schemes of FIGS. 1 and 2 wherein the compounds are identified by the same designator in both the Examples and the Figures.
Example 1
[0078] (R)-4-(tert-Butyldimethylsilanyloxy)cyclopent-2-enone (2).
[0079] Tetrapropylammonium perruthenate (9.4 mg, 0.027 mmol) was added to a mixture of (1S, 4R)-4-(tert-butyldimethylsilanyloxy)cyclopent-2-enol prepared, according to Tetrahedron Letters, Vol. 37, No. 18, 1996, pp. 3083-6, (118.6 mg, 0.54 mmol), 4-methylmorpholine N-oxide (94.9 mg, 0.81 mmol) and crushed 4Å sieves (270 mg) in CH 2 Cl 2 (10 mL). The mixture was stirred for 30 min and was passed through a plug of silica gel with CH 2 Cl 2 . The filtrate was concentrated in vacuo to give 100 mg (86%) of the above titled compound.
Example 2
[0080] (R)-4-(tert-Butyldimethylsilanyloxy)-6-oxabicyclo[3.1.0]hexan-2-one (3).
[0081] Hydrogen peroxide (4.5 mL, 46.3 mmol, 30% wt. % solution in water) and 1N NaOH (46 μL, 0.046 mmol) were added to a solution of enone 2 (2.5 g, 11.5 mmol) in MeOH (30 mL) at 0° C. After stirring 1.5 h at 0° C. the mixture was concentrated in vacuo, washed with saturated aqueous NH 4 Cl and extracted with CH 2 Cl 2 (3×). The combined organics were washed with brine, dried (Na 2 SO 4 ), filtered and concentrated in vacuo to afford the above titled compound.
Example 3
[0082] ({-[3-[(R)-3-(tert-Butyldimethylsilanyloxy)-5-oxocyclopent-1-enylsulfanyl]propylsulfanyl}acetic acid methyl ester (5).
[0083] The epoxide 3 prepared above was diluted with CH 2 Cl 2 (30 mL), (3-mercaptopropylsulfanyl) acetic acid methyl ester 4 (1.93 g, 10.7 mmol), prepared according to Chem. Pharm. Bull. 28 (2), 1980, 558-566, was added and the solution was cooled to 0° C. Basic alumina (11.9 g) was added and the reaction mixture was warmed to room temperature. After stirring for 18 h the mixture was filtered through celite and concentrated in vacuo. The residue was purified by flash column chromatography (silica gel, 6:1 hex/EtOAc) to yield 3.6 g (80%) of the above titled compound.
Example 4
[0084] (3-{(1R,2S,3R)-3-(tert-Butyldimethylsilanyloxy)-2-[(S)-(E)-3-(tert-butyldimethylsilanoxy)oct-1-enyl]-5-oxocyclopentylsulfanyl} propylsulfanyl)acetic acid methyl ester (7).
[0085] tert-Butyllithium (1.47 mL of a 1.7M solution in pentane, 2.5 mmol) was added dropwise to a solution of tert-butyl[(S)-1-((E)-2-iodovinyl) hexyloxy]dimethylsilane 6 (462.5 mg, 1.25 mmol) in Et 2 O (6.0 mL) at −78° C. After stirring for 30 min lithium 2-thienylcyanocuprate (6.0 mL of a 0.25M solution in THF, 1.5 mmol) was added and the reaction was stirred an additional 30 min at −78° C. A solution of enone 5 (430 mg, 1.1 mmol) in Et 2 O (1 mL) was added and stirring was continued for an additional 1 h. The reaction mixture was then quickly poured into saturated aqueous NH 4 Cl cooled to 0° C. The mixture was extracted with EtOAc and the organic portion was washed with brine, dried (Na 2 SO 4 ), filtered and concentrated in vacuo. The residue was quickly purified by flash column chromatography (silica gel, 100% hexane followed by 8:1 hex/EtOAc) to afford 270 mg (39%) of the above titled compound.
Example 5
[0086] {3-[(1R,2S,3R)-3-Hydroxy-2-((S)-(E)-3-hydroxyoct-1-enyl)-5-oxocyclopentylsulfanyl]propylsulfanyl}acetic acid methyl ester (8).
[0087] Hydrogen fluoride-pyridine (220 μL) was added to a solution of bis-TBDMS ether 7 (70 mg, 0.11 mmol) in CH 3 CN (2.0 mL) at 0° C. The reaction was warmed to room temperature, stirred 1 h, and recooled to 0° C. The reaction was quenched with saturated aqueous NaHCO 3 until gas evolution ceased. The mixture was extracted with CH 2 Cl 2 (4×). The combined organics were washed with brine, dried (Na 2 SO 4 ), filtered and concentrated in vacuo. Purification of the residue by flash column chromatography (silica gel, 100% CH 2 Cl 2 followed by 30:1 CH 2 Cl 2 :MeOH) provided 40 mg (90%) of the above titled compound.
Example 6
[0088] {3-[(1R,2S,3R)-3-Hydroxy-2-((S)-(E)-3-hydroxyoct-1-enyl)-5-oxocyclopentylsulfanyl]propylsulfanyl}acetic acid (9).
[0089] Methyl ester 8 (50 mg, 0.124 mmol) was dissolved in CH 3 CN (10 mL) and pH 7.2 phosphate buffer (3.0 mL) was added. The mixture was treated with PLE (400 μL, 1.34 mol/L) and stirred for 16 h at 23° C. The reaction mixture was extracted with EtOAc (3×). The combined organics were washed with brine, dried (Na 2 SO 4 ), filtered and concentrated in vacuo. Purification of the residue by flash column chromatography (silica gel, 100% EtOAc) gave 5.3 mg (11%) of the above titled compound.
Example 7
[0090] {3-[(1R,2S,3R)-3-Hydroxy-2-((S)-(E)-3-hydroxyoct-1-enyl)-5-oxocyclopentylulfanyl]propylsulfanyl}acetic acid isopropyl ester (10).
[0091] Isopropyl-p-tolyltriazene (200 μL) was added dropwise to a solution of carboxylic acid 9 (10.5 mg, 0.026 mmol) in acetone (5.0 mL) at 23° C. After stirring for 1 h the reaction was quenched with 1N HCl and the solvent was removed in vacuo. The residue was extracted with CH 2 Cl 2 (2×). The combined organics were dried (Na 2 SO 4 ), filtered and concentrated in vacuo. Purification of the residue by flash column chromatography (silica gel, 4:1 hex/EtOAc) gave 4.3 mg (38%) of the above titled compound.
Example 8
[0092] (3-{(1R,2S,3R)-3-(tert-Butyldimethylsilanyloxy)-2-[(S)-(E)-3-(tert-butyldimethylsilanoxy)-5-(naphthyl)pent-1-enyl]-5oxocyclopentylsulfanyl}propylsulfanyl)acetic acid methyl ester (H).
[0093] (3-{(1R,2S,3R)-3-(tert-Butyldimethylsilanyloxy)-2-[(S)-(E)-3-(tert-butyldimethylsilanoxy)-5-(naphthyl)pent-1-enyl]-5oxocyclopentylsulfanyl]propylsulfanyl)acetic acid methyl ester (L).
[0094] The named compound is prepared by substituting tert-butyl-[(E)-3-iodo-1- (2-naphthalen-2-yl-ethyl)allyloxy]dimethylsilane for tert-butyl[(S)-1-((E)-2-iodovinyl)hexyloxy]dimethylsilane in the method of Example 4. FCC gives a higher Rf compound and a lower Rf compound, designated as H and L, respectively.
Example 9(H)
[0095] {3-[(1R,2S,3R)-3-Hydroxy-2-((S)-(E)-3-(hydroxy)-5-(naphthyl)pent-1-enyl)-5-oxocyclopentylsulfanyl]propylsulfanyl}acetic acid methyl ester (H).
[0096] The named compound is prepared by repeating the method of Example 5 with the named compound of Example 8 (H) rather then the named compound of Example 4.
Example 9 (L)
[0097] {3-[(1R,2S,3R)-3-Hydroxy-2-((S)-(E)-3-(hydroxy)-5-(naphthyl)pent-1-enyl)-5-oxocyclopentylsulfanyl]propylsulfanyl}acetic acid methyl ester (L).
[0098] The named compound is prepared by repeating the method of Example 5 with the named compound of Example 8 (L) rather then the named compound of Example 4.
Example 10 (H)
[0099] {3-[(1R,2S,3R)-3-Hydroxy-2-((S)-(E)-3-(hydroxy)-5-(naphthyl)pent-1-enyl)-5-oxocyclopentylsulfanyl]propylsulfanyl}acetic acid (H).
[0100] The named compound is prepared by repeating the method of Example 6 with the named compound of Example 9 (H) rather than the named compound of Example 5.
Example 10 (L)
[0101] {3-[(1R,2S,3R)-3-Hydroxy-2-((S)-(E)-3-(hydroxy)-5-(naphthyl)pent-1-enyl)-5-oxocyclopentylsulfanyl]propylsulfanyl}acetic acid (L).
[0102] The named compound is prepared by repeating the method of Example 6 with the named compound of Example 9 (L) rather than the named compound of Example 5.
Example 11
[0103] {3-[(1R,2S,3R)-3-Hydroxy-2-((S)-(E)-3-(hydroxy)-5-(naphthyl)pent-1-enyl)-5oxocyclopentylsulfanyl]propylsulfanyl}acetic acid isopropyl ester.
[0104] The named compound is prepared by repeating the method of Example 7 with the named compound of Example 10 rather than the named compound of Example 6.
Example 12
[0105] (3-{(1R,2S,3R)-3-(tert-Butyldimethylsilanyloxy)-2-[(S)-(E)-3-(tert-butyldimethylsilanoxy)-5-(benzothienyl)pent-1-enyl]-5-oxocyclopentylsulfanyl}propylsulfanyl)acetic acid methyl ester (H).
[0106] (3-{(1R,2S,3R)-3-(tert-Butyldimethylsilanyloxy)-2-[(S)-(E)-3-(tert-butyldimethylsilanoxy)-5-(benzothienyl)pent-1-enyl]-5-oxocyclopentylsulfanyl}propylsulfanyl)acetic acid methyl ester (L).
[0107] The named compound is prepared by substituting [(E)-1-(2-Benzo[b)thiophen-2-yl-ethyl)-3-iodoallyloxy]-tert-butyldimethylsilane for tert-butyl[(S)-1-((E)-2-iodovinyl)hexyloxy]dimethylsilane in the method of Example 4. FCC gives a higher Rf compound and a lower Rf compound, designated as H and L, respectively.
Example 13(H)
[0108] {3-[(1R,2S,3R)-3-Hydroxy-2-((S)-(E)-3-hydroxy-5-(benzothienyl)pent-1-enyl)-5-oxocyclopentylsulfanyl]propylsulfanyl}acetic acid methyl ester (H).
[0109] The named compound is prepared by repeating the method of Example 5 with the named compound of Example 12 (H) rather then the named compound of Example 4.
Example 13(L)
[0110] {3-[(1R,2S,3R)-3-Hydroxy-2-((S)-(E)-3-hydroxy-5-(benzothienyl)pent-1-enyl)-5-oxocyclopentylsulfanyl]propylsulfanyl}acetic acid methyl ester (L).
[0111] The named compound is prepared by repeating the method of Example 5 with the named compound of Example 12 (H) rather then the named compound of Example 4.
Example 14(H)
[0112] {3-[(1R,2S,3R)-3-Hydroxy-2-((S)-(E)-3-hydroxy-5-(benzothienyl)pent-1-enyl)-5-oxocyclopentylsulfanyl]propylsulfanyl}acetic acid (H).
[0113] The named compound is prepared by repeating the method of Example 6 with the named compound of Example 13 (H) rather than the named compound of Example 5.
Example 14(L)
[0114] {3-[(1R,2S,3R)-3-Hydroxy-2-((S)-(E)-3-hydroxy-5-(benzothienyl)pent-1-enyl)-5-oxocyclopentylsulfanyl]propylsulfanyl}acetic acid (L).
[0115] The named compound is prepared by repeating the method of Example 6 with the named compound of Example 13 (L) rather than the named compound of Example 5.
Example 15
[0116] {3-[(1R,2S,3R)-3-Hydroxy-2-((S)-(E)-3-hydroxy-5-(benzothienyl)pent-1enyl)-5-oxocyclopentylsulfanyl]propylsulfanyl}acetic acid isopropyl ester.
[0117] The named compound is prepared by repeating the method of Example 7 with the named compound of Example 14 rather than the named compound of Example 6.
Example 16
[0118] (34(1R,2S,3R)-3-(tert-Butyldimethylsilanyloxy)-2-[(S)-(E)-3-(tert-butyldimethylsilanoxy)-5-(benzofuranyl)pent-1-enyl]-5oxocyclopentylsulfanyl}propylsulfanyl)acetic acid methyl ester.
[0119] The named compound is prepared by substituting [(E)-1-(2-Benzo[b]furan-yl-ethyl)-3-iodoallyloxy]-tert-butyldimethylsilane for tert-butyl[(S)-1-((E)-2iodovinyl) hexyloxy]dimethylsilane in the method of Example 4.
Example 17
[0120] {3-[(1R,2S,3R)-3-Hydroxy-2-((S)-(E)-3-hydroxy-5-(benzofuranyl)pent-1-enyl)-5-oxocyclopentylsulfanyl]propylsulfanyl}acetic acid methyl ester.
[0121] The named compound is prepared by repeating the method of Example 5 with the named compound of Example 16 rather then the named compound of Example 4.
Example 18
[0122] {3-[(1R,2S,3R)-3-Hydroxy-2-((S)-(E)-3-hydroxy-5-(benzofuranyl)pent-1enyl)-5-oxocyclopentylsulfanyl]propylsulfanyl}acetic acid.
[0123] The named compound is prepared by repeating the method of Example 6 with the named compound of Example 17 rather than the named compound of Example 5.
Example 19
[0124] {3-[(1R,2S,3R)-3-Hydroxy-2-((S)-(E)-3-hydroxy-5-(benzofuranyl)pent-1-enyl)-5-oxocyclopentylsulfanyl]propylsulfanyl}acetic acid isopropyl ester.
[0125] The named compound is prepared by repeating the method of Example 7 with the named compound of Example 18 rather than the named compound of Example 6.
Example 20
[0126] (3-{(1R,2S,3R)-3-(tert-Butyldimethylsilanyloxy)-2-[(E)-3-(tert-butyldimethylsilanoxy)-4-naphthalen-2-yl-but-1-enyl]-5-oxocyclopentylsulfanyl]propylsulfanyl)acetic acid methyl ester (H).
[0127] (3{(1R,2S,3R)-3-(tert-Butyldimethylsilanyloxy)-2-[(E)-3-(tert-butyldimethylsilanoxy)-4-naphthalen-2-yl-but-1-enyl]-5-oxocyclopentylsulfanyl}propylsulfanyl)acetic acid methyl ester (L).
[0128] The named compound is prepared by substituting tert-butyl-((E)-3-iodo-1-naphthalen-2-yl-methylallyloxy)dimethylsilane for tert-butyl[(S)-1-((E)-2-iodovinyl) hexyloxy]dimethylsilane in the method of Example 4. FCC gives a higher Rf compound and a lower Rf compound, designated as H and L, respectively.
Example 21 (H)
[0129] 3-[(1R,2S,3R)-3-Hydroxy-2-((E)-3-hydroxy-4-naphthalen-2-yl-but-1-enyl)-5-oxocyclopentylsulfanyl]propylsulfanyl}acetic acid methyl ester (H).
[0130] The named compound is prepared by repeating the method of Example 5 with the named compound of Example 20 (H) rather then the named compound of Example 4.
Example 21(L)
[0131] {3-[(1R,2S,3R)-3-Hydroxy-2-((E)-3-hydroxy-4-naphthalen-2-yl-but-1-enyl)-5-oxocyclopentylsulfanyl]propylsulfanyl}acetic acid methyl ester (L).
[0132] The named compound is prepared by repeating the method of Example 5 with e named compound of Example 20 (H) rather then the named compound of ample 4.
Example 22(H)
[0133] {3-[(1R,2S,3R)-3-Hydroxy-2-((E)-3-hydroxy-4-naphthalen-2-yl-but-1-enyl)-5-oxocyclopentylsulfanyl]propylsulfanyl}acetic acid (H).
[0134] The named compound is prepared by repeating the method of Example 6 with the named compound of Example 21 (H) rather than the named compound of Example 5.
Example 22(L)
[0135] {3-[(1R,2S,3R)-3-Hydroxy-2-((E)-3-hydroxy-4-naphthalen-2-yl-but-1-enyl)-5oxocyclopentylsulfanyl]propylsulfanyl}acetic acid (L).
[0136] The named compound is prepared by repeating the method of Example 6 with the named compound of Example 21 (H) rather than the named compound of Example 5.
Example 23
[0137] {3-[(1R,2S,3R)-2-[(E)-4-Benzo[b]thiophen-3-yl-3-(tert-butyldimethylsilanyloxy)but-1-enyl]-3-(tert-butyldimethylsilanyloxy)-5-oxocyclopentylsulfanyl]propylsulfanyl}acetic acid methyl ester (H).
[0138] {3-[(1R,2S,3R)-2-[(E)-4-Benzo[b]thiophen-3-yl-3-(tert-butyldimethylsilanyloxy)but-1-enyl]-3-(tert-butyldimethylsilanyloxy)-5-oxocyclopentylsulfanyl]propylsulfanyl}acetic acid methyl ester (L).
[0139] The named compound is prepared by substituting ((E)-1-Benzo[b]thiophen-3-ylmethyl-3-iodo-allyloxy)-tert-butyldimethylsilane for tert-butyl[(S)-1-((E)-2-iodovinyl)hexyloxy]dimethylsilane in the method of Example 4. FCC gives a higher Rf compound and a lower Rf compound, designated as H and L respectively.
Example 24(H)
[0140] {3-[(1R,2S,3R)-2-((E)-4-Benzo[b]thiophen-3-yl-3-hydroxybut-1-enyl)-3-hydroxy-5-oxocyclopentylsulfanyl]propylsulfanyl}acetic acid methyl ester (H).
[0141] The named compound is prepared by repeating the method of Example 5 with the named compound of Example 23 (H) rather then the named compound of Example 4.
Example 24(L)
[0142] {3-[(1R,2S,3R)-2-((E)-4-Benzo[b]thiophen-3-yl-3-hydroxybut-1-enyl)-3-hydroxy-5-oxocyclopentylsulfanyl]propylsulfanyl}acetic acid methyl ester (L).
[0143] The named compound is prepared by repeating the method of Example 5 with the named compound of Example 23 (H) rather then the named compound of Example 4.
Example 25(H) {3-[(1R,2S,3R)-2-((E)-4-Benzo[b]thiophen-3-yl-3-hydroxybut-1-enyl)-3-hydroxy-5-oxocyclopentylsulfanyl]propylsulfanyl}acetic acid (H).
[0144] The named compound is prepared by repeating the method of Example 6 with the named compound of Example 24 (H) rather than the named compound of Example 5.
Example 25(L)
[0145] {3-[(1R,2S,3R)-2-((E)-4-Benzo[b]thiophen-3-yl-3-hydroxybut-1-enyl)-3-hydroxy-5-oxocyclopentylsulfanyl]propylsulfanyl}acetic acid (L).
[0146] The named compound is prepared by repeating the method of Example 6 with the named compound of Example 24 (H) rather than the named compound of Example 5.
Example 26
[0147] (3-{(1R,2S,3R)-3-(tert-Butyldimethylsilanyloxy)-2-[(S)-(E)-3-(tert-butyldimethylsilanoxy)-3-(methyl)-5-(naphthyl)pent-1-enyl]-5-oxocyclopentylsulfanyl}propylsulfanyl)acetic acid methyl ester (H).
[0148] (3-{(1R,2S,3R)-3-(tert-Butyldimethylsilanyloxy)-2-[(S)-(E)-3-(tert-butyldimethylsilanoxy)-3-(methyl)-5-(naphthyl)pent-1-enyl]-5-oxocyclopentylsulfanyl}propylsulfanyl)acetic acid methyl ester (L).
[0149] The named compound is prepared by substituting tert-Butyl-[(E)-3-iodo-1-methyl-1-(2-naphthalen-2-yl-ethyl)allyloxy]dimethylsilane for tert-butyl[(S)-1-((E) 2 -iodovinyl)hexyloxy]dimethylsilane in the method of Example 4. FCC gives a higher Rf compound and a lower Rf compound, designated as H and L, respectively.
Example 27(H)
[0150] {3-[(1R,2S,3R)-3-Hydroxy-2-((S)-(E)-3-(hydroxy)-3-(methyl)-5-(naphthyl)pent-1-enyl)-5-oxocyclopentylsulfanyl]propylsulfanyl}acetic acid methyl ester (H).
[0151] The named compound is prepared by repeating the method of Example 5 with the named compound of Example 26 (H) rather then the named compound of Example 4.
Example 27(L)
[0152] {3-[(1R,2S,3R)-3-Hydroxy-2-((S)-(E)-3-(hydroxy)-3-(methyl)-5(naphthyl)pent-1-enyl)-5-oxocyclopentylsulfanyl]propylsulfanyl}acetic acid methyl ester (L).
[0153] The named compound is prepared by repeating the method of Example 5 with the named compound of Example 26 (H) rather then the named compound of Example 4.
Example 28(H)
[0154] {3-[(1R,2S,3R)-3-Hydroxy-2-((S)-(E)-3-(hydroxy)-3-(methyl)-5-(naphthyl)pent-1-enyl)-5-oxocyclopentylsulfanyl]propylsulfanyl)acetic acid (H).
[0155] The named compound is prepared by repeating the method of Example 6 with the named compound of Example 27 (H) rather than the named compound of Example 5. Example 28(L
[0156] {3-[(1R,2S,3R)-3-Hydroxy-2-((S)-(E)-3-(hydroxy)-3-(methyl)-5(naphthyl)pent-1-enyl)-5-oxocyclopentylsulfanyl]propylsulfanyl}acetic acid (L).
[0157] The named compound is prepared by repeating the method of Example 6 with the named compound of Example 27(L) rather than the named compound of Example 5.
Example 29
[0158] (3-{(1R,2S,3R)-3-(tert-Butyldimethylsilanyloxy)-2-[(E)-3-(tert-butyldimethylsilanoxy)-3-methyl-4-naphthalen-2-yl-but-1-enyl]-5-oxocyclopentylsulfanyl}propylsulfanyl)acetic acid methyl ester (H).
[0159] (3-{(1R,2S,3R)-3-(tert-Butyldimethylsilanyloxy)-2-[(E)-3-(tert-butyldimethylsilanoxy)-3-methyl-4-naphthalen-2-yl-but-1-enyl]-5-oxocyclopentylsulfanyl}propylsulfanyl)acetic acid methyl ester (L).
[0160] The named compound is prepared by substituting tert-butyl-[(E)-3-iodo-1-ethyl-1-(2-naphthalen-2-yl-methyl)allyloxy]dimethylsilane for tert-butyl[(S)-1-(E)-2-iodovinyl) hexyloxy]dimethylsilane in the method of Example 4. FCC gives a higher Rf compound and a lower Rf compound, designated as H and L, respectively.
Example 30(H)
[0161] {3-[(1R,2S,3R)-3-Hydroxy-2-((E)-3-hydroxy-3-methyl-4-naphthalen-2-yl-but-1-enyl)-5-oxocyclopentylsulfanyl]propylsulfanyl}acetic acid methyl ester (H).
[0162] The named compound is prepared by repeating the method of Example 5 with the named compound of Example 29 (H) rather then the named compound of Example 4.
Example 30(L)
[0163] {3-[(1R,2S,3R)-3-Hydroxy-2-((E)-3-hydroxy-3-methyl-4-naphthalen-2-yl-but-1-enyl)-5-oxocyclopentylsulfanyl]propylsulfanyl}acetic acid methyl ester (L).
[0164] The named compound is prepared by repeating the method of Example 5 with the named compound of Example 29 (L) rather then the named compound of Example 4.
Example 31(H)
[0165] 3-[(1R,2S,3R)-3-Hydroxy-2-((E)-3-hydroxy-3-methyl-4-naphthalen-2-yl-but-1-enyl)-5-oxocyclopentylsulfanyl]propylsulfanyl}acetic acid (H).
[0166] The named compound is prepared by repeating the method of Example 6 with the named compound of Example 30 (H) rather than the named compound of Example 5.
Example 31(L)
[0167] {3-[(1R,2S,3R)-3-Hydroxy-2-((E)-3-hydroxy-3-methyl-4-naphthalen-2-yl-but-1-enyl)-5-oxocyclopentylsulfanyl]propylsulfanyl}acetic acid (L).
[0168] The named compound is prepared by repeating the method of Example 6 with the named compound of Example 30 (L) rather than the named compound of Example 5.
Example 32
[0169] (3-{(1R,2S,3R)-3-(tert-Butyldimethylsilanyloxy)-2-[(S)-(E)-3-(tert-butyldimethylsilanoxy)-3-(methyl)-5-(benzylthienyl)pent-1-enyl]-5-oxocyclopentylsulfanyl}propylsulfanyl)acetic acid methyl ester (H).
[0170] (3-{(1R,2S,3R)-3-(tert-Butyldimethylsilanyloxy)-2-[(S)-(E)-3-(tert-butyldimethylsilanoxy)-3-(methyl)-5-(benzothienyl)pent-1-enyl]-5-oxocyclopentylsulfanyl}propylsulfanyl)acetic acid methyl ester (L).
[0171] The named compound is prepared by [(E)-1-(2-Benzo[b]thiophen-2-ylethyl)-3-iodo-1-methylallyloxy]-tert-butyldimethylsilane for tert-butyl[(S)-1-((E)-2-iodovinyl) hexyloxy]dimethylsilane in the method of Example 4. FCC gives a higher Rf compound and a lower Rf compound, designated as H and L, respectively.
Example 33(H)
[0172] {3-[(1R,2S,3-R)-3-Hydroxy-2-((S)-(E)-3-(hydroxy)-3-(methyl)-5(benzothienyl)pent-1-enyl)-5-oxocyclopentylsulfanyl]propylsulfanyl}acetic acid methyl ester (H).
[0173] The named compound is prepared by repeating the method of Example 5 with the named compound of Example 32 (H) rather then the named compound of Example 4.
Example 33(L)
[0174] {3-[(1R,2S,3R)-3-Hydroxy-2-((S)-(E)-3-(hydroxy)-3-(methyl)-5(benzothienyl)pent-1-enyl)-5-oxocyclopentylsulfanyl]propylsulfanyl}acetic acid methyl ester (L).
[0175] The named compound is prepared by repeating the method of Example 5 with the named compound of Example 32 (L) rather then the named compound of Example 4.
Example 34(H)
[0176] {3-[(1R,2S,3R)-3-Hydroxy-2-((S)-(E)-3-(hydroxy)-3-(methyl)-5-(benzothienyl)pent-1-enyl)-5-oxocyclopentylsulfanyl]propylsulfanyl}acetic acid (H).
[0177] The named compound is prepared by repeating the method of Example 6 with the named compound of Example 33 (H) rather than the named compound of Example 5.
Example 34(L)
[0178] {3-[(1R,2S,3R)-3-Hydroxy-2-((S)-(E)-3-(hydroxy)-3-(methyl)-5-(benzothienyl)pent-1-enyl)-5-oxocyclopentylsulfanyl]propylsulfanyl}acetic acid (L).
[0179] The named compound is prepared by repeating the method of Example 6 with the named compound of Example 33L rather than the named compound of Example 5.
[0180] The effects of the compounds of this invention on intraocular pressure may be measured as follows. The compounds are prepared at the desired concentrations in a vehicle comprising 0.1% polysorbate 80 and 10 mM TRIS base. Dogs are treated by administering 25 μl to the ocular surface, the contralateral eye receives vehicle as a control. Intraocular pressure is measured by applanation pneumatonometry. Dog intraocular pressure is measured immediately before drug administration and at 6 hours thereafter.
[0181] The compounds of Examples 9H, 9L, 10H, 10L, 13H, 13L, 14H, 14L, 21H, 21L, 22H, 22L, 24H, 25H, 25L, 27H, 27L, 28H, 28L, 30H, 30L, 31H, 31L, 33H, 33L, 34H and 34L are useful in lowering elevated intraocular pressure in mammals, e.g. humans.
[0182] The compounds of the Examples are subject to in vitro testing as described below. The results are reported in the table.
Ex- ample No. hEP 4 33H 200 33L 300 34H 32 34L 68 13H 91 13L 93 14H 27 14L 13 9H 40 9L 40 10H 450 10L 19.5 27H 500 27L 3400 28H 1700 28L 1500 21H 100 21L 13 22H 32 22L 6.2 30H 3100 30L 3200 31H 300 31L 900 24H 200 24L 30 25H 69 25L 5
[0183] Human Recombinant EP 4 Receptor: Stable Transfectants.
[0184] Plasmids encoding the human EP 4 receptor were prepared by cloning the respective coding sequences into the eukaryotic expression vector pCEP4 (Invitrogen). The pCEP4 vector contains an Epstein Barr virus (EBV) origin of replication, which permits episomal replication in primate cell lines expressing EBV nuclear antigen (EBNA-1). It also contains a hygromycin resistance gene that is used for eukaryotic selection. The cells employed for stable transfection were human embryonic kidney cells (HEK-293) that were transfected with and express the EBNA-1 protein. These HEK-293-EBNA cells (Invitrogen) were grown in medium containing Geneticin (G418) to maintain expression of the EBNA-1 protein. HEK-293 cells were grown in DMEM with 10% fetal bovine serum (FBS), 250 μg ml −1 G418 (Life Technologies) and 200 μg ml −1 gentamicin or penicillin/streptomycin. Selection of stable transfectants was achieved with 200R 9 ml −1 hygromycin, the optimal concentration being determined by previous hygromycin kill curve studies.
[0185] For transfection, the cells were grown to 50-60% confluency on 10 cm plates. The plasmid pCEP4 incorporating cDNA inserts for the respective human prostanoid receptor (20 μg) was added to 500 μl of 250 mM CaCl 2 . HEPES buffered saline×2 (2×HBS, 280 mM NaCl, 20 mM HEPES acid, 1.5 mM Na 2 HPO 4 , pH 7.05-7.12) was then added dropwise to a total of 500 μl, with continuous vortexing at room temperature. After 30 min, 9 ml DMEM were added to the mixture. The DNA/DMEM/calcium phosphate mixture was then added to the cells, which had been previously rinsed with 10 ml PBS. The cells were then incubated for 5 hr at 37° C. in humidified 95% air/5% CO 2 . The calcium phosphate solution was then removed and the cells were treated with 10% glycerol in DMEM for 2 min. The glycerol solution was then replaced by DMEM with 10% FBS. The cells were incubated overnight and the medium was replaced by DMEM/10% FBS containing 250 μg ml −1 G418 and penicillin/streptomycin. The following day hygromycin B was added to a final concentration of 200 μg ml − .
[0186] Ten days after transfection, hygromycin B resistant clones were individually selected and transferred to a separate well on a 24 well plate. At confluence each clone was transferred to one well of a 6 well plate, and then expanded in a 10 cm dish. Cells were maintained under continuous hygromycin selection until use.
[0187] The foregoing description details specific methods and compositions that can be employed to practice the present invention, and represents the best mode contemplated. However, it is apparent for one of ordinary skill in the art that further compounds with the desired pharmacological properties can be prepared in an analogous manner, and that the disclosed compounds can also be obtained from different starting compounds via different chemical reactions. Similarly, different pharmaceutical compositions may be prepared and used with substantially the same result. For example, the EP4 agonists disclosed and claimed U.S. Pat. No. 6,410,591 B1, which is hereby incorporated by reference may be used in the method of the present invention. In addition, GR 50209×, a receptor selective EP 4 -receptor agonist, may also be used in the method of the present invention. (GR 50209×has the following structure:
[0188] Thus, however detailed the foregoing may appear in text, it should not be construed as limiting the overall scope hereof; rather, the ambit of the present invention is to be governed only by the lawful construction of the appended claims. | The present invention provides a method of treating ocular hypertension or glaucoma which comprises administering to an animal having ocular hypertension or glaucoma therapeutically effective amount of a compound which is a EP 4 agonist. | 8 |
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation of application Ser. No. 12/490,911, filed Jun. 24, 2009, which is a continuation of application Ser. No. 11/654,367, filed Jan. 17, 2007, now U.S. Pat. No. 7,554,796, which claims the benefit of provisional application Ser. No. 60/760,598, filed Jan. 20, 2006 and provisional application Ser. No. 60/762,915, filed Jan. 27, 2006, which applications are hereby incorporated by reference in their entirety.
FIELD OF THE INVENTION
The present invention relates to a power distribution panel with circuit element modules.
BACKGROUND OF THE INVENTION
Electrical circuit panels such as power distribution panels typically include a number of different circuit elements such as fuse holders and fuses, circuit breakers, input and output connectors and alarm signal LED's. For safety and other reasons, the electrical circuits of power distribution panels are enclosed within a housing structure. Therefore, the circuit elements listed above have typically been inserted into holes that have been pre-cut or pre-punched into the housing structure, usually on a front or back panel of the housing structure.
These prior circuit panels are fixed and once the holes are formed in the housing, the type and arrangement of the components is limited. In order to manufacture different fixed circuit panels of the prior systems, a circuit panel manufacturer would punch out different patterns of holes in the front or back panels of the housing structure in order to accommodate different arrangements of circuit elements. Significant retooling time and costs are involved for offering different fixed panels. Assembly of the circuit elements is also difficult when the elements are inserted through holes. One solution is described and shown in U.S. Pat. No. 6,456,203.
In addition, such panels are hardwired between the input and output connections, and the fuse and/or breaker locations. In some panels, redundant power connections are provided, controlled by an OR-ing diode including a heat sink. These features can take up significant space within the panel.
There is a continued need for improved power distribution panels.
SUMMARY OF THE INVENTION
A modular power distribution system comprises a chassis; and a backplane including a power input, and a plurality of module connection locations. A plurality of modules are mounted in the chassis, each module mounted to one of the module connection locations. Each module includes: (i) an OR-ing diode; (ii) a circuit protection device; (iii) a microprocessor controlling the circuit protection device; and (iv) a power output connection location. A circuit option switch is located on each module for setting the current limits for each module. A system control module is provided connected to the backplane.
A modular power distribution system comprises a chassis having an open front and an interior; and a backplane positioned opposite to the open front, and including a power input, and a plurality of module connection locations. A plurality of modules are mounted in the interior of the chassis, each module mounted to one of the module connection locations. Each module includes: (i) a rear connector; (ii) a main body; (iii) a circuit protection device; (iv) a front panel; and (v) a power output connection location on the front panel.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic side view of one embodiment of a power distribution panel, with a module partially inserted into the chassis.
FIG. 2 is a schematic side view of another embodiment of a power distribution panel, with a module partially inserted into the chassis.
FIG. 3 is a schematic top view of the power distribution panel of FIG. 1 .
FIG. 4 is a schematic top view of an alternative embodiment of a power distribution panel.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIGS. 1 and 2 , power distribution systems 10 , 110 are shown. Power distribution systems 10 , 110 are modular designs including a chassis 12 and removable circuit modules 14 , 114 . Each circuit module 14 , 114 includes an electronic breaker 16 , 116 for circuit protection, and a port assembly 18 , 118 for output power distribution.
Chassis 12 includes a top 34 and a bottom 36 . A backplane 38 , such as a printed circuit board, provides the interconnection between modules 14 , 114 and power input connector 26 . Preferably, a second (redundant) power input connector 27 is provided (see FIG. 3 ).
Modules 14 , 114 are received in chassis 12 through a front opening 20 . Modules 14 , 114 can be removed through front opening 20 as desired to repair, replace or service the modules. Modules 14 , 114 can be latched or otherwise attached to chassis 12 , as desired.
Modules 14 , 114 are similar in many respects for distributing and monitoring the power in systems 10 , 110 . Modules 14 , 114 each include a printed circuit board 42 with circuitry for linking the input power to the output power. Modules 14 , 114 differ in the arrangements for the power outputs at port assemblies 18 , 118 . Module 10 includes a single power output connector 72 , such as a high power connector including a DB9-2W2 connector; whereas module 110 includes a plurality of separate power output connectors 172 , such as lower power connectors including screw terminals.
The electronic breakers 16 , 116 are part of active circuit modules 14 , 114 to replace discrete fuses and circuit breaker used in prior art power distribution panels. The end user adds, removes, or upgrades ports in the power distribution system as required by adding or removing circuit modules 14 , 114 .
Each circuit module 14 , 114 can be used as a 1 A, 2 A, 10 A, etc. breaker by setting current limit options switches 22 . For example, 2 position DIP switches could be used. Prior art panels with discrete fuses and breakers have a single trip value. Control logic 24 including microcontroller 28 monitors the output current via current sensors 30 , 130 . If the output current exceeds the limits set by option switches 22 , microcontroller 28 will turn-off (“trip”) a breaker device 32 , which is preferably a solid-state device. The current limit set by the option switches 22 can also be overridden via a software interface from a remote terminal through a control module 40 (see FIGS. 3 and 4 ). Microprocessor 28 is networked to an external processor through control module 40 . If a breaker device 32 is tripped due to the detection of an over current condition, microcontroller 28 will periodically re-enable breaker device 32 to see if the fault still exists. This can eliminate a service visit if the over current was caused by a momentary transient condition.
Microcontroller 28 provides control over breaker device 32 . This eliminates disconnects caused by source or load transients. Microcontroller 28 can also set a breaker trip point based on load monitoring over time. Microcontroller 28 is also equipped with a history file that records various conditions local to the individual circuit modules 14 , 114 . This information is accessible via the control module 40 .
Microprocessor 28 can include a load dependent trip control algorithm. This option allows microprocessor 28 to set the breaker trip point for a given load based on a learning algorithm. Microprocessor 28 monitors outgoing current over time (can be a user selectable time period). Microprocessor 28 is configured to calculate a margin of error, then use the new value to create a trip value for each circuit module 14 , 114 . For example, one circuit module 14 is used in a 30 amp circuit. However, typically the circuit only draws a 27 amp load. Mircroprocessor 28 recognizes the 27 amp load by monitoring the current load over time, then adds a margin of error (e.g., 1%-5%) to create a load dependent trip value. Therefore, the circuit will trip before 30 amps is ever drawn. Such a system prevents over fusing, and damaged equipment.
Low voltage disconnect (LVD) is localized to the circuit modules 14 , 114 . Under voltage conditions are monitored by microcontroller 28 with an under voltage sensor 46 . If the voltage drops below the recommended level, microcontroller 28 will turn breaker device 32 off to disconnect the load. The same process will occur if an over voltage condition occurs. Over voltage conditions are monitored by microcontroller 28 with an over voltage sensor 48 .
To support redundant (dual feed) applications, the OR-ing diodes 54 are localized to the individual circuit modules 14 , 114 . Prior art power distribution panels that used OR-ing diodes placed them in the input circuits which required very large diodes and heat sinks and created a single point of failure for the system. The arrangement of systems 10 , 110 allows the heat dissipated by the OR-ing diodes 54 to be evenly distributed in chassis 12 preventing a localized hot spot. The noted arrangement also reduces the size of the diodes and their respective heat sinks, and eliminates the single point of failure common in prior art power distribution panels. Circuit modules 14 , 114 can also include a temperature sensor 50 for monitoring high temperature conditions.
An LED indicator 62 on each circuit module 14 , 114 provides a visual status of input and output voltage, output current, temperature, over/under voltage conditions, and breaker trip. A local reset switch 68 is also provided to reset the breaker device 32 after a trip condition has occurred.
In circuit module 14 , all input and output to the electronic breaker 16 is via a high current connector 18 to prevent accidental contact by service personnel. Circuit module 14 includes a front connector 72 , and a rear connector 76 . Front connector 72 connects to cable connector 82 and cable 86 for the output power. Rear connector 76 connects to chassis backplane connector 84 for input power to module 14 . The high power connector also prevents polarity reversals.
Front connectors 172 of circuit module 114 each connect to a power output connector 182 and cable 186 . Power output connector 182 may be a lug for screw connection to front connector 172 .
Systems 10 , 110 eliminate internal wiring normally required in prior art power distribution panels. All power and signaling is confined to PCB traces, planes, and bus bars, which improves reliability and reduces assembly cost. Chassis 12 is a passive component that can be reconfigured for a variety of applications. Systems 10 , 110 also reduce the number of connections and thermal loss associated with each connection.
All circuit modules 14 , 114 in chassis 12 communicate with control module 40 . Control module 40 provides access to systems 10 , 110 via a laptop serial or network connection for status and alarm information. Control module 40 also provides the external alarms signals common in Telco application. Access to control module 40 is through a front connector 56 , or through a rear connector 58 on a back of backplane 38 .
Chassis 12 in FIG. 3 has rear input power connectors 26 , 27 , and front accessible circuit modules 14 . A modified chassis 112 in system 10 ′ as shown in FIG. 4 includes front accessible input power connectors 126 , 127 .
Circuit modules 14 , 114 and control module 40 can be provided with front face plates 86 to protect the interior circuit features. Ventilation holes 88 can be added through front face plates 86 , to allow for airflow through systems 10 , 10 ′, 110 for cooling of system components.
The above noted panels include modular arrangements for the individual or groupings of circuits. Additional modules can be added as additional circuits are added to the system. By utilizing localized OR-ing, smaller diodes and smaller heat sinks can be used. Additional advantages arise from the localized components associated with each module. In particular, with a localized low voltage disconnect elements, there is no need for a large low voltage disconnect contactors associated with a dedicated panel. Local LED indicators show indicators for each module allowing for improved diagnostics. | A modular power distribution system comprises a chassis; and a backplane including a power input, and a plurality of module connection locations. A plurality of modules are mounted in the chassis, each module mounted to one of the module connection locations. Each module includes: (i) an OR-ing diode; (ii) a circuit protection device; (iii) a microprocessor controlling the circuit protection device; and (iv) a power output connection location. A circuit option switch is located on each module for setting the current limits for each module. A control module is provided connected to the backplane. | 7 |
This application is a divisional of U.S. application Ser. No. 09/363,397 filed Jul. 29, 1999 now U.S. Pat. No. 6,214,708 (allowed).
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a method and an apparatus for diffusing zinc (Zn) into groups III-V compound semiconductors. The groups III-V compound semiconductor means a semiconductor of a pair of a group III element gallium(Ga), indium(In) or aluminum(Al), and a group V element arsenic(As), phosphorus(P) or antimony(Sb). Bulk single crystal wafers are available for GaAs, InP and GaP. GaAs wafers, InP wafers and GaP wafers are useful as substrates of laser diodes (LDs), light emitting diodes (LEDs), photodiodes (PDs) or other semiconductor devices. Though this invention can be applied to any III-V compound semiconductor wafers, explanation will be done by only citing GaAs and InP.
The III-V compound semiconductor wafers are inherently n-type in many cases. Fabrication of a pn-junction requires epitaxial growth of p-type thin films on the n-type wafer, ion implantation of a p-type impurity, or thermal diffusion of a p-type impurity into the n-type wafer. The epitaxial growth of the p-type films is improper for making localized p-regions through a mask. The ion implantation is not the most suitable, since it requires a large apparatus, a plenty of steps and annealing of the ion implanted wafer, which raise the cost of producing the pn-junction. The thermal diffusion is the most suitable way for making pn-junctions in an n-type wafer. Zinc (Zn) acts as a p-type impurity in GaAs or InP crystals. Magnesium (Mg) and cadmium (Cd) are also p-type impurities in GaAs or InP, but Zn is the most feasible p-impurity for InP or GaAs. Zn-diffusion is one of the most important techniques of fabricating LEDs, LDs, PDs and other semiconductor devices having the group III-V semiconductor substrates. The purpose of the Zn-diffusion is to make localized p-regions on a crystal by diffusion.
Here, the crystal includes substrate crystals and film crystals grown on substrate crystals. A purpose of the present invention is to provide a new Zn-diffusion method and apparatus applicable to a wide wafer. Another purpose of the present invention is to provide a Zn-diffusion method and apparatus of high controllability. A further purpose of the present invention is to provide a Zn-diffusion method and apparatus immune from the use of poisonous materials.
This invention is a version of vapor phase diffusion methods but is different from conventional vapor phase diffusion methods. This invention is rather akin to liquid phase epitaxy (LPE). This invention rather diverts the manner and the device from the liquid phase epitaxy to the Zn-diffusion. Though this invention resembles the liquid phase epitaxy, this invention is essentially a vapor phase diffusion of Zn. Instead of material liquid, a vapor of Zn is filled in a sliding jig. This invention is not epitaxy but diffusion. This invention must be clearly discriminated from the liquid phase epitaxy.
This application claims the priority of Japanese Patent Application No.10-213954(10-213954) filed on Jul. 29, 1998 which is incorporated herein by reference.
2. Description of Prior Art
Impurity diffusion is classified into two categories of vapor phase diffusion and solid phase diffusion by the distinction whether the impurity is supplied from solid phase or vapor phase. There is no concept of “liquid phase diffusion”. The solid phase diffusion is a new technology recently proposed by the present Inventors for the first time (Japanese Patent Application No.5-177233, Japanese Patent Laying Open No.7-14791). The solid phase diffusion method has steps of growing a Zn-containing InGaAsP film epitaxially on an n-InP crystal substrate and diffusing Zn from the InGaAsP film into the InP substrate by heat. Since the object InP is protected by the InGaAsP film, P atoms do not escape from the bottom InP substrate in spite of heating in the solid phase diffusion. However, an excess number of steps have been prohibiting the practical use of the solid phase diffusion.
The Zn-diffusion is still actually done exclusively by vapor phase diffusion. The vapor phase diffusion is further classified into two methods. One of the vapor phase diffusion methods is a closed tube method. The other is an open tube method. Both two methods are well known. But only the closed tube method is put into practice on a large scale in the semiconductor industry at present. The open tube method is poorly employed on a small scale in some laboratories, because the open tube method is still suffering from unsolved difficulties. Two methods are explained in detail for clarifying the present state of the art of impurity diffusion.
[A. Closed Tube Method]
FIG. 14 shows a closed tube method for diffusing Zn into a group III-V semiconductor wafer. A long quartz tube 61 having an open end and a closed end is prepared. An InP wafer (or GaAs wafer) 62 is put on an inner spot near an end 60 of the quartz tube 61 . A diffusion source 66 is put on an inner point near the other end 65 of the quartz tube 61 . The quartz tube 61 is vacuumed and the open end is sealed by an oxygen-hydrogen flame burner. Sometimes the quartz tube 61 necks in a part 63 containing the solid diffusion source 66 . The Zn diffusion source 66 is either a sublimable compound of Zn and As or a sublimable compound of Zn and P. For example, zinc phosphide (ZnP 2 ), zinc arsenide (ZnAs 2 ) or so is selected as a material of the Zn-diffusion source, because they satisfy the conditions of inclusion of Zn, sublimability from solid phase to vapor phase and immunity from foreign materials except Zn and the substrate material. This method is called a closed tube method, because the quartz tube is fully closed.
The sealed quartz tube 61 is put into a horizontal furnace having heaters 67 and 68 . The furnace heaters 67 and 68 heat the whole of the quartz tube 61 and maintain the Zn-diffusion source 66 at a higher temperature than the wafer 62 . The Zn-diffusion source 66 sublimes into vapor at the higher temperature. The vapor flies in the quartz tube to the wafer 62 of GaAs or InP and adheres to the wafer at the lower temperature. The Zn atoms diffuse deeply in the wafer by heat. The diffusion depth in the wafer can be controlled by the temperature and the time. After the determined time has passed, the temperature of the furnace is reduced. When the furnace is cooled to a pertinent temperature, the quartz tube 61 is pulled out of the furnace. The object GaAs wafer (or InP wafer) is taken out by breaking the quartz tube 61 . The wafer is provided with pn-junctions by the Zn-diffusion.
FIG. 15 shows an improvement of the closed tube method. A long quartz tube 70 is prepared. A diffusion source 76 is put in at an end 75 of the quartz tube 70 . A GaAs wafer (or an InP wafer) 74 is placed in a half-closed short tube 73 . The half-closed tube 73 is put in at a middle of the quartz tube 70 . A vacuum is formed in the quartz tube 70 and the tube end is sealed by the oxygen-hydrogen flame burner. The closed tube is inserted into a furnace having heaters 79 , 80 and 82 . The diffusion source 76 is heated to the highest temperature by the heater 79 for subliming the source material. The middle part of the tube is heated at the lowest temperature by the heater 80 for converting the diffusion material vapor into powder and once depositing the powder 78 on the inner wall. Then, the powder 78 is heated for flying to the GaAs wafer 74 for depositing on the wafer. There are some new proposals of the close tube methods other than the method of FIG. 15 .
Why the tube must be sealed in the closed tube method? The sealing is required for the necessity of controlling the vapor pressure of the group V element (As or P). The closed space enables the dissolving speed of the diffusion source to uniquely determine the vapor pressure of the group V element. The dissolving speed is determined only by the temperature T of the diffusion source. Namely, in the closed tube, the vapor pressure is controlled only by the temperature T of the diffusion source. Maintaining the balance between the dissolution and the absorption of the group V element on the wafer surface, the close tube method carries the Zn compound in vapor phase from the diffusion source to the wafer, deposits the Zn atoms on the wafer and diffuses the Zn atoms deeply into the wafer.
The time and the temperature determine the depth and the concentration of diffusion. Only the closed tube method among various diffusion methods is practically used on a large scale in the semiconductor industry. The closed tube method has many advantages. The wafers are immune from contamination, because Zn is diffused in a closed space separated from the external environments. A great amount of gas is unnecessary. The wafers are not oxidized. The diffusion is stable. The reliability of diffusion is high in the case of deep diffusion. The closed tube method is a matured technique having a long, rich history. Since it is already an old, ripened technique, it is difficult to cite an original document which describes the typical closed tube method. Instead, some proposals for improvements will be explained now.
{circle around (1)} Japanese Patent Laying Open No.60-53018, “method of diffusing impurities into a compound semiconductor” suggested a new way of vapor phase diffusion of zinc (Zn) into InP. Pointing out a problem of prior diffusion of an excess diffusion speed caused by sealing only an InP wafer and a diffusion source of ZnP 2 or Zn 3 P 2 , {circle around (1)} proposed an addition of a solid phosphorus (P) in the close tube for decreasing the diffusion speed. When the closed quartz tube is heated, the P-vapor pressure is raised by the sublimation of the newly added P solid in the closed tube. The Zn-vapor pressure is suppressed by the P-vapor pressure, since the total pressure is restricted by the temperature. The addition of the P-vapor pressure reduces the diffusion speed through the decrement of the Zn-vapor pressure. The solid P plays the role of retarding the diffusion of Zn.
Why must the closed tube method cut down the diffusion speed? Would the high speed diffusion bring about high throughput? It is, however, wrong. Large heat capacity accompanies the quartz closed tube owing a large length and a big thickness. It takes about 15 minutes to heat the quartz tube up to a temperature between 500° C. and 600° C. in the furnace. But the time of diffusion for making a 2 μm deep p-region is only 10 minutes due to the rapid diffusion. It takes several tens of minutes to cool the furnace for decreasing the temperature to room temperature. Heating and cooling of the whole of the quartz tube require a long time due to the large length and the big thickness.
The large heat capacity allows the quartz tube to change the temperature moderately and continually but forbids the tube from varying temperature rapidly. The sublimation of the diffusion source and the Zn-diffusion start even at the step of rising temperature due to the slow change of temperature. The diffusion still continues even at the step of cooling. The diffusion also occurs at extra steps other than the diffusion step. Since the closed tube method controls the diffusion only by temperature, it is impossible to control the start and the end of the diffusion exactly. Since heating and cooling require a longer time than diffusion, the depth of diffusion cannot be correctly determined. There is another problem of the contamination of the wafer by the Zn, because condensed Zn comes to adhering to the wafer surface at the step of cooling. For overcoming these drawbacks, {circle around (1)} tried to suppress the extra diffusion accompanying the heating step and the cooling step by supplying the P solid in the quartz tube, raising the P-vapor pressure and decreasing the Zn-vapor pressure.
[B. Open Tube Method]
A quartz tube having openings at both ends is prepared. The open tube method diffuses Zn into an InP wafer or a GaAs wafer by supplying the InP wafer (or GaAs wafer) into the quartz tube, heating the tube to a pertinent temperature, supplying a Zn-containing metallorganic gas and a As- or P-containing gas, for example, arsine (AsH 3 ) or phosphine (PH 3 ) into the open quartz tube. The Zn-containing metallorganic gas is prepared from a metallorganic compound having Zn which is liquid at room temperature, for example, dimethyl zinc (Zn(CH 3 ) 2 ). The Zn-containing metallorganic gas is made by bubbling the metallorganic compound with hydrogen gas. The Zn-containing gas is introduced into the quartz tube from an opening end and becomes in contact with the heated GaAs (or InP) wafer. The metallorganic gas (e.g.,dimethyl zinc) is dissociated by heat into zinc atoms and hydrocarbons. Zn atoms are adsorbed on the surface of the wafer. Zn atoms cover the surface of the wafer. High temperature gives the wafer a high diffusion coefficient. Zn atoms diffuse from the surface to the inner part along with the inclination of the Zn-concentration.
If the wafer were to be bluntly heated in vacuum, the group V atoms would escape from the surface of the III-V wafer owing to the high dissociation pressure at a high temperature. The open tube method introduces PH 3 gas or AsH 3 gas for heightening the vapor pressure of the group V element in order to forbid the group V atoms from dissociating out of the surface. The high pressure of the group V gas balances the dissociation with the adsorption of the group V atoms on the surface of the wafer. The balance of the open tube method is a dynamic balance in which the flowing gas (PH 3 or AsH 3 ) protects the wafer from dissociation in stead of perfect equilibrium by the static gas. The open tube method is inferior to the closed tube method in the vapor pressure balance. Since the tube is not sealed, the open tube method, however, can treat far larger wafers than the closed tube method. Possibility of processing a large sized wafer is the most conspicuous feature of the open tube method. Another advantage is the sparing of quartz tubes. Someone considers that the open tube method may excel in controllability, because the gas flows are ruled by valve operations. The open tube method, however, has not been practiced on a large scale in factories of the semiconductor industry yet, but has been adopted only for the purpose of experiments in some universities. For example,
{circle around (2)} T. Tsuchiya, T. Taniwatari, T. Haga, T. Kawano, “High-quality Zn-diffused InP-related materials fabricated by the open-tube technique”, 7th International Conference of Indium Phosphide and Related Materials p664 (1995, Sapporo) reported a Zn-diffusion by supplying a mixture gas of hydrogen (H 2 ), dimethyl-Zn, phosphine (PH 3 ) to an InGaAsP/InP epitaxial wafer in an MOCVD apparatus. Instead of preparing an inherent open tube diffusion apparatus, the MOCVD apparatus was diverted to an open tube method for diffusion. Since the open tube method requires only a heater and an enclosed space which allow gases to flow, the MOCVD apparatus can be a substitute for the quartz tube in the open tube method. Temporary diversion of the MOCVD apparatus on a small scale can be allowed. However, the MOCVD is an apparatus not for diffusion but for epitaxy. Such a high cost diversion would be forbidden on a large, industrial scale.
{circle around (3)} Japanese Patent Laying Open No.62-143421 “method and apparatus for diffusing an impurity” proposed an improvement of the open tube method. It denied the closed tube method for the reason that the diffusion starts midway of the step of rising temperature. FIG. 16 shows the proposed improvement having a horizontal quartz tube 83 with inlets 85 and 86 , and an outlet 87 . An InP wafer 84 is put at a spot near the outlet 87 within the quartz tube 83 . A Zn-source 88 (Zn 2 P) is laid at another spot near the inlet 86 in the quartz tube 83 . An inactive gas is supplied into the tube 83 via the middle inlet 85 . The flow of the inactive gas can separate the InP wafer 84 from the Zn-source 88 . During the steps of rising temperature (heating step) and decreasing temperature (cooling step), the InP wafer 84 is effectively separated from the Zn-source 88 by, blowing the inactive gas into the tube 83 from the middle inlet 85 . During the step of diffusion, the flow of the inactive gas is stopped and hydrogen gas is supplied into the tube 83 from the end inlet 86 . The hydrogen gas carries the vapor including Zn from the Zn-source 88 to the InP wafer 84 . The Zn atoms are adsorbed on the surface of the wafer 84 . The high temperature forces the Zn atoms to diffuse into the InP crystal. Operation bars penetrate into the tube through the side valves 89 and 90 for conveying the wafer 84 and the diffusion source 88 . The swift change of the gases enables the open tube apparatus to forbid the diffusion from occurring during the cooling step and the heating step. The advocates assert that the open tube method can control exactly the depth of diffusion through the timely control of the gas flow.
The closed tube method is endowed with strong points of controllability of the group V gas pressure, saving of material gases, immunity from contamination and practical achievements. Despite many proposals, only the closed tube method is a practical Zn-diffusion method which has been widely carried out on a large scale in the semiconductor industry. The closed tube method, however, is suffering from a drawback of the difficulty of treating large-sized wafers. Since the closed tube method inserts an object wafer into a quartz tube (ampoule), the quartz tube having an inner diameter larger than the outer diameter of the object wafer should be employed. Not automated manipulators but skilled workers still do all the diffusion steps of inserting a wafer, putting an impurity source in a transparent quartz tube, making the tube vacuous and sealing an open end of the quartz tube by a oxygen-hydrogen flame burner. The formidable difficulty forces the experienced technician to handle the sealing step, excluding the possibility of the automatic sealing by a machine. The high melting point of quartz compels the technician to use the oxygen-hydrogen burner. The sealing operation includes the steps of evacuating the tube by a vacuum pump, softening a part of the quartz tube by the burner flame, narrowing the softened part, shutting the tube at the narrowing part, separating the other part of the quartz tube which is still evacuated by the vacuum pump and rounding the separated end of the part containing the wafer and the diffusion source by the burner. All the steps are done by manual operation of the skilled technician.
An increase of the diameter of the quartz tube raises the difficulty of the vacuum sealing of the quartz tube. One-inch diameter InP wafers have been used so far for making LEDs, LDs, PDs or other devices. But two-inch wafers will be employed for making the devices in near future for enhancing the throughput of the wafer process. If a two-inch diameter InP wafer should be inserted into a 3 mm-thick quartz tube, the outer diameter of the quartz tube would be at least 56 mm. It is extremely difficult even for an expert to seal such a wide quartz tube having a diameter of at least 56 mm. The vacuum sealing of the wide quartz tube requires an exquisite skill of an experienced technician.
The closed tube method has another weak point of the necessity of breaking the transparent, expensive quartz tube for taking the treated wafer out. The broken quartz tube cannot be reused. The broken parts of the expensive quartz tube must be thrown into a garbage pit. It is a waste of expensive natural resources. Further, since the quartz tube is broken down, the fragments are spattered. Some of the fragments adhere to the wafer. Further, the spattered fragments sometimes hurt the wafer.
There is a further drawback in the current closed tube method. It is poor controllability, since the diffusion is controlled only by the temperature. The poor controllability submits the unexpected diffusion occurring even during the (heating) step of rising temperature of the quartz tube. In addition, the undesirable diffusion also takes place even during the (cooling) step of decreasing the temperature. It is difficult to repeat the same profile of temperature change of the heating step, the diffusing step and the cooling step many times. Since the temperature profiles fluctuate every cycle of processes. The poor controllability leads to poor reproductivity of the diffusion depth. The diffusion depths disperse at random, in particular, in the case of shallow diffusion. Another difficulty is undesirable deposition of Zn atoms on the wafer during the cooling step. The closed tube method, therefore, is suffering from the problem of the poor controllability and the problem of the technical difficulty in the case of treating large-sized wafers. A desired diffusion method would be excellent in the controllability of diffusion and the applicability to larger wafers.
On the contrary, the open tube method is more suitable for treating large-sized wafers than the closed tube method. A larger wafer may be treated only by replacing the quartz tube by a larger tube. Since the open tube method does not seal the ends of the reaction tube, this method is immune from the technical difficulty of sealing the quartz tube. The open tube method, however, is plagued by other difficulties. The vapor pressure of the group V gas is unstable, because the group V gas and the Zn-containing gas flow in the tube. The instability of the group V gas may invite the dissociation of the V element atoms from the wafer surface. The open tube method has a more serious drawback. A great amount of the V element gas is supplied into the tube for maintaining the V gas pressure. The V element gas, for example, arsine (AsH 3 ) or phosphine (PH 3 ), is a strong poison. Protection of the environments would require a large-scaled depollution equipment of the exhaustion gas for the open tube method. The open tube method needs a highly expensive, large apparatus on an industrial scale. Thus, the semiconductor industry has not yet employed the well-known open tube method as Zn-diffusion technology.
SUMMARY OF THE INVENTION
One purpose of the present invention is to provide a Zn-diffusion method and apparatus enabling Zn to diffuse into large InP or GaAs wafers. Another purpose of the present invention is to provide an inexpensive Zn-diffusion method and apparatus without large scaled equipment. A further purpose of the present invention is to provide a Zn-diffusion method and apparatus which forbid the extra diffusion during the heating step and the cooling step. A further purpose of the present invention is to provide a Zn-diffusion method enabling to control exactly the timing of the beginning or the finishing of the Zn-diffusion by pertinent ways other than controlling the temperature. A further purpose of the present invention is to provide a Zn-diffusion method and apparatus enabling to control the density of group V element vacancies. A further purpose of the present invention is to provide a Zn-diffusion method and apparatus immune from the use of poisonous gases.
The diffusion method of the invention includes the steps of preparing a horizontal, long base plank having an exhaustion hole and a wafer-storing cavity, inserting a group III-V compound sample wafer into the cavity of the base plank, preparing a slider consisting of a frame with serially aligning M rooms with an open bottom and a rack being separated from each other by (M−1) partition walls, a non-doped capping wafer affixed at a front end of the frame and a cap plate for covering a top of the frame, taking the cap plate off the top of the slider, putting one of a Zn-diffusion source and a V element source turn by turn on each rack of the serially-aligning rooms, fixing the cap plate on the top of the frame for covering the open top of the slider, laying the slider on the base plank, affixing a manipulating bar to the slider, putting the base plank into a tube, making an inner space of the tube vacuous, carrying the slider by the manipulating bar at spots where each room lies in turn just above the exhaustion hole for evacuating each room through the exhaustion hole, carrying the slider by the manipulating bar to a spot for covering the sample wafer with the capping wafer of the slider, inserting the tube into a furnace with heaters, heating the base plank, the sample wafer and the slider, moving the slider at a spot for covering the sample wafer with the room having the diffusion source when the temperature attains to a pertinent temperature for diffusion, diffusing the Zn atoms into the sample wafer for a determined time at a pertinent temperature in the diffusion source room as a first diffusion process, moving the slider to a spot for covering the sample wafer with the room having the V element source, changing the temperature of the sample wafer to a temperature pertinent to following diffusion by regulating power of the heaters, moving the slider to a spot for covering the sample wafer with the following room having the diffusion source, diffusing the Zn atoms into the sample wafer for a determined time at a pertinent temperature in the diffusion source room as a second diffusion process, repeating necessary cycles of the steps of changing temperature and the steps of the Zn-diffusion, and finally moving the slider at a spot away from the sample wafer for cooling the sample wafer in a state separating from the diffusion room of the slider.
This invention uses a slider for diffusion of Zn unlike the prior closed tube method or the open tube method. The slider has a frame and a cap plate. The frame has an outer walls and inner partition walls. The frame contains M rooms of an open bottom and an open top separating by the (M−1) partition walls. The cap plate covers the open tops of the rooms of the frame. Each room has a rack on a side wall for holding a Zn-diffusion source or a V element source. When the slider is heated in a closed state, the rooms are filled with the vapor of the diffusion source or the vapor of the V element. Optionally, a non-doped capping wafer accompanies the slider at a front end. The slider is put upon a long, horizontal, flat base plank. The slider is equipped with a manipulating bar for sliding the slider in a longitudinal direction on the base plank.
The base plank has a cavity for storing a sample wafer to be doped with Zn and an exhaustion hole. The base plank is inserted into a tube, e.g., quartz tube, which can be made vacuous by a vacuum pump. Once the gas is evacuated out of the tube and hydrogen gas is introduced into the tube as atmosphere gas. Hydrogen gas accelerates the heating and the cooling of the tube through reinforcing the convection and the heat conduction. The tube is loaded into a preheated furnace having heaters. The heaters heat the base plank, the slider, the diffusion sources and the V element sources. The diffusion source room or the V element room in turn occupies at a spot just above the sample wafer by displacing the slider upon the base plank by the manipulating bar. When the V element room having the V element gas occupies the wafer spot, the wafer is heated to a suitable temperature. When the wafer is heated to the temperature, the slider should be moved for coinciding the diffusion room having the Zn-diffusion source with the wafer spot for starting the diffusion.
In the diffusion room, Zn is diffused into the wafer in vapor phase, since the diffusion room in the slider is full of the diffusion source gas. When the vapor phase diffusion finishes, the diffusion room is separated from the sample wafer by displacing the slider by the manipulating bar. In the case of multiple diffusion for diffusing Zn to the same wafer more than once at different temperatures, the wafer should be held in the V element room or under the capping wafer for changing the temperature of the wafer under the V element pressure. When the temperature attains to the determined temperature, the slider is moved for coinciding the sample wafer with the next diffusion room. Alternatively, the bottom of the V element room can be closed by a non-doped wafer. The sample wafer should be separated from the diffusion room of the slider during the step of cooling for preventing the extra diffusion.
The sample wafer is protected by the V element room or the non-doped capping wafer during the step of changing the temperature of the wafer, for example, heating or cooling. M denotes the number of the rooms of the slider. M rooms have an opening bottom and an opening top. There are two kinds of sliders. One kind has a capping wafer either in front of or at the back of the frame. The other kind has no capping wafer. The capping wafer plays a similar role to the V element room for protecting the wafer from losing the V element.
In the case of the non-capping wafer, the room number M is two or more than two (M≧2), since the slider must contain at least one V element room and at least one diffusion room. K-time diffusion requires K diffusion rooms and K V element rooms which align in turn. Thus, M=2K for the K-time diffusion. In addition, a cooling room having V element can accompany the slider. In the case, the slider includes (K+1) V element rooms and K diffusion rooms.
In the case of the front capping wafer, the room number M is one or more than one (M≧1), since the front capping wafer plays a similar role of the V element room. K-time diffusion requires (K−1) V element rooms and K diffusion rooms. Then, M=2K−1 for the K-time diffusion. If a cooling room is additionally equipped, the room number is M=2K. Some of the V element rooms can be replaced by capping wafer, since the roles of them are similar.
There are several variations even for a determined time of diffusion. For example, a K time diffusion contains the following six Versions;
Version 1. A capping wafer+(2K−1) room slider
Version 2. 2K room slider
Version 3. A capping wafer+2K room slider
Version 4. (2K+1) room slider
Version 5. A capping wafer+(2K−1) room slider+a capping wafer
Version 6. 2K room slider+capping wafer
Versions 1,3 and 5 enclose an object wafer with a capping wafer during the heating process for preventing the V element from escaping. Versions 2, 4 and 6 enclose an object wafer with a V element room for preventing the V element from escaping. The difference relates to the rising temperature process (heating process).
The cooling step gives different versions. Versions 1 and 2 cool the wafer in hydrogen atmosphere in the tube, because the wafer is not protected at the cooling step. All the embodiments that will be explained later belong to Versions 1 or 2. Version 1 gives the slider an array of diffusion room+V element room+diffusion room+ . . . +diffusion room (M=2K−1). Version 2 gives the slider another array of V element room+diffusion room+ . . . +diffusion room+V element room+diffusion room (M=2K).
Versions 3 and 4 protect the object wafer by the last V element room during the cooling step for avoiding the dissociation of the V element. The slider of Version 3 has an array of diffusion room+V element room+diffusion room+ . . . +diffusion room+V element room (M=2K). The slider of Version 4 has an array of V element room+diffusion room+ . . . +diffusion room+V element room (M=2K+1).
Versions 5 and 6 protect the object wafer by the additional end capping wafer during the cooling step for avoiding the dissociation of the V element. The slider of Version 5 has an array of diffusion room+V element room+diffusion room+ . . . +diffusion room (M=2K−1). The slider of Version 6 has an array of V element room+diffusion room+ . . . +diffusion room (M=2K).
The base plank is a long smooth even plank allowing the slider to slide without friction but preventing vapor from leaking through the gap between the base plank and the slider. Evenness, flatness, refractory and lubricancy are essential to the base plank. The base plank can be made from, for example, carbon. Carbon excels in heat resistance and lubricancy. Sliding on carbon may yield carbon dust. Thus, the carbon should be coated with amorphous carbon (a-C) or silicon carbide (SiC). It is possible to fix a carbon capping plate upon a carbon frame with carbon screws.
The Zn diffusion material should be solid at room temperature and should sublime at high temperature without melting. The candidates of the diffusion material are Zn 3 P 2 , ZnP 2 , Zn 3 P 2 +P(red phosphorus), ZnP 2 +P(red phosphorus). The V element material is the V component of the object wafer. The V element material is P for an InP wafer and As for a GaAs wafer.
This invention has big advantages. Unlike the closed tube method, this invention allows Zn compounds to diffuse into large sized wafers. The large size brings about no difficulty in the present invention. This invention treats with large sized wafers by enlarging the diffusion rooms and the V element rooms in the slider. This invention can easily be applied to a wafer larger than 2 inch in diameter. This invention is superior to the closed tube method in the applicability to large sized wafers. Extra diffusion does not occur at the heating step and at the cooling step, since the wafer is separated from the diffusion source. The displacement of the slider gives desired diffusion density distribution to the wafer. This invention enhances the controllability of the dopant distribution in the direction of thickness. This invention is immune from the problem of dopant deposition on the wafer surface at the cooling step, since the wafer is isolated from the dopant(Zn compound). The inner space of the diffusion room is so small and narrow that this invention dispenses with a large volume of V element gas flow. A reduction of poisonous V element gas improves the safety. This invention is superior to the open tube method in the gas consumption, the freedom of the dopant deposition and the safety.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 ( 1 ) is a sectional view of Embodiment 1 of a slider having a single diffusion room at the step of vacuuming the diffusion room.
FIG. 1 ( 2 ) is a sectional view of Embodiment 1 at the step of heating the apparatus and an object wafer.
FIG. 1 ( 3 ) is a sectional view of Embodiment 1 at the step of diffusing impurity into the object wafer.
FIG. 1 ( 4 ) is a sectional view of Embodiment 1 at the step of cooling the apparatus.
FIG. 2 is a plan view of the slider of Embodiment 1 in an open state without the cap.
FIG. 3 is a plan view of the slider of Embodiment 1 in a closed state with the cap.
FIG. 4 is a graph of the time dependence on the temperature of the diffusion room in Embodiment 1.
FIG. 5 is a sectional view of the slider, the base plank, the quartz tube and the reaction furnace of Embodiment 1.
FIG. 6 is a graph showing the relation between the diffusion depth and the root square of diffusion time at 580° C. on non-doped InP wafers and Sn-doped InP wafers.
FIG. 7 ( 1 ) is a sectional view of Embodiment 2 of a slider having a diffusion room and a V-element room at the step of vacuuming the V-element room(red phosphorus room).
FIG. 7 ( 2 ) is a sectional view of Embodiment 2 at the step of vacuuming the diffusion room.
FIG. 7 ( 3 ) is a sectional view of Embodiment 2 at the step of heating the apparatus and an object wafer.
FIG. 7 ( 4 ) is a sectional view of Embodiment 2 at the step of diffusing impurity into the object wafer.
FIG. 7 ( 5 ) is a sectional view of Embodiment 2 at the step of cooling the apparatus.
FIG. 8 is a plan view of the slider of Embodiment 2 having the V-element room and the diffusion room in an open state without the cap.
FIG. 9 is a plan view of the slider of Embodiment 2 in a closed state with the cap.
FIG. 10 is a graph showing the time dependence on the temperature in Embodiment 2 having a V element room instead of the capping wafer.
FIG. 11 is a section of a three-room slider for twice diffusion of Embodiment 3.
FIG. 12 is a plan view of the three-room slider without the cap for twice diffusion of Embodiment 3.
FIG. 13 is the time dependence of the temperature for twice diffusion of Embodiment 3.
FIG. 14 is a section of an impurity diffusion apparatus of a closed tube method.
FIG. 15 is a section of an impurity diffusion apparatus of the closed tube method disclosed by Japanese Patent Publication No.2-24369.
FIG. 16 is a section of an impurity diffusion apparatus of the open tube method disclosed by Japanese Patent Laying Open No.62-143421.
FIG. 17 is a section of a three-room slider for twice diffusion of Embodiment 3 which employs a capping wafer instead of the V element room.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Embodiment 1: Single Room Type Slider; Rough Capping Wafer; Single Time Diffusion
Embodiment 1 relates to single time diffusion, employing a non-doped capping wafer with a rough surface. Embodiment 1 covers an object wafer in the cavity by the non-doped capping wafer for protecting the object wafer against the dissociation of V element during the heating step (rising temperature step), moves the slider above the object wafer when the wafer attains to the diffusion temperature Td, starts the Zn diffusion into the object wafer and separates the slider from the object wafer when the diffusion finishes for isolating the object wafer from the diffusion vapor atmosphere.
FIG. 1, FIG. 2 and FIG. 3 denote Embodiment 1. FIG. 1 shows the steps of the Zn diffusion of the present invention. FIG. 2 is a plan view of a frame and a capping wafer. FIG. 3 is a plan view of a slider and the capping wafer. This is a device for a single wafer. A double-sized slider for treating two wafers can be produced by enlarging the width twice in the lateral direction. Furthermore, a slider including m wafers can be made instead of the single wafer slider of FIG. 2 and FIG. 3 . The pertinent size of the frame of the slider can be determined by considering the required throughput.
The parts shown by FIG. 1 are contained in a reaction chamber, for example, a quartz tube 20 , as shown in FIG. 5 . The reaction chamber can be evacuated. A base plank 1 is a long smooth even carbon table elongating in a longitudinal direction. The base plank 1 is inserted into the reaction chamber. The carbon base plank 1 has a good resistance against chemicals and good sliding performance. Naked carbon may appear on the surface of the base plank 1 . It is preferable to coat at least the upper surface of the base plank 1 by some hard material for preventing the base plank 1 from inducing carbon powder by friction. The base plank 1 may be coated with, for example, silicon carbide (SiC) or amorphous carbon (a-C). The base plank 1 can otherwise be made from refractory metal, for instance, tantalum (Ta), tungsten (W) or stainless steel. A shallow wafer-storing cavity 2 is perforated on the base plank 1 for maintaining an object wafer 14 . The size of the cavity 2 is determined by the object wafer 14 . An exhaustion hole 3 is pierced vertically in the base plank 1 .
An important part is a slider 4 . The slider 4 has a top wall and side walls with a bottom open. The slider 4 has a rectangular frame 5 and a capping plate 6 . FIG. 2 shows only the frame 5 . FIG. 3 denotes the slider 4 with the cap plate 6 . In the example, the inner space within the slider 4 has a 30 mm width, a 30 mm length and a 20 mm height with a volume of 18 cm 3 . The slider 4 is put on the base plank 1 with the open bottom down. When the open bottom coincides with the exhaustion hole 3 , a vacuum is formed in the inner space of the slider 4 by absorbing gases from the exhaustion hole 3 . The cap plate 6 is fixed upon the rectangular frame 5 by screws 7 .
The open bottom of the frame 5 slides on the base plank 1 , keeping a direct contact therewith. The smooth and flat bottom brings the slider 4 into tight contact with the base plank 1 without leak. The frame 5 is made from, e.g. carbon which allows exact processing within a tolerance of several microns. The side walls of the slider 4 have a thickness between 10 mm and 20 mm. The cap plate 6 can be made from carbon. Preferably, the carbon frame 5 and the cap plate 6 should be coated with SiC or a-C like the base plank 1 .
A hole 8 is perforated on the cap plate 6 and the frame 5 for inserting an L-shaped end of a manipulating bar 9 . The slider 4 is moved forward or backward by the manipulating bar 9 on the base plank 1 . Conventional liquid phase epitaxy (LPE) is used to move a slider by a manipulating bar on a base plank. It is also analogy from the conventional LPE to make the slider from carbon. But in fact, the slider or the cap plate can be made from stainless steel or other metals.
The frame 5 , the cap plate 6 and the base plank 1 form a diffusion room 10 . The diffusion room 10 is a small, movable space. The movability of the slider 4 is an origin of the excellent controllability of the present invention. The diffusion room 10 has a rack 12 on the side wall for storing a diffusion material 11 . The diffusion material depends upon the object wafer. In the case of an InP wafer, the diffusion material should be a compound of Zn and P, for example, Zn 3 P 2 or ZnP 2 . In the case of a GaAs wafer, the diffusion material should be a compound of Zn and As, for example, Zn 3 As 2 or ZnAs 2 . In general, the diffusion material should be a sublimable compound including Zn and the V element of the object wafer. The rack 12 sustains a solid diffusion material. When the diffusion room 10 is heated, the diffusion room 10 is full of the vapor of the material. The tight contact of the slider 4 on the base plank 1 prevents the vapor of the material from leaking outward.
The diffusion material 11 is loaded in the slider 4 by taking the cap plate 6 off the frame 5 , supplying a solid diffusion material 11 on the rack 12 , laying the cap plate 6 upon the frame 5 , fixing the cap plate 6 on the frame 5 by the screws 7 . Then, the L-end of the manipulating bar 9 is inserted into the hole 8 .
The slider 4 has a non-doped capping wafer 13 at the front end. The non-doped capping wafer 13 has a rough surface facing to an object wafer for enhancing the function of suppressing dissociation of the V element of the object wafer. The capping wafer 13 moves together with the slider 4 on the base plank 1 , since the capping wafer 13 is stuck to the slider 4 . The material of the capping wafer 13 has the same material as the object wafer. An InP capping wafer should be employed for an InP object wafer. A GaAs object wafer requires a GaAs capping wafer. The capping wafer 13 plays the role of covering the object wafer 14 during the heating step for inhibiting the V element from escaping the object wafer 14 . In general, III-V compound semiconductors, e.g., InP and GaAs, should be suppressed at high temperatures by V element vapor pressure, since the V element has a big dissociation pressure. When the object wafer 14 is heated in the cavity 2 , the capping wafer is simultaneously heated on the base plank 1 . The capping wafer 13 discharges the V element gas from the ragged surface for filling the narrow space within the cavity 2 with e.g., As-gas or P-gas. The capping wafer 13 suppresses the dissociation of the V element from the object wafer 14 .
The capping wafer 13 should be a non-doped wafer. Otherwise impurities would be transferred from the capping wafer 13 to the object wafer 14 . The surface facing the object wafer 14 is not polished but roughened. The roughed surface enhances the discharge of the V element gas from the capping wafer 14 by enlarging the effective area of the surface. The narrow space within the cavity 2 and the capping wafer 14 is occupied by the V element vapor. A tip of a thermocouple 15 is in contact with the base plank 1 beneath the object wafer 14 .
The following steps shown in FIG. 1 will be done according to the temperature change of FIG. 4 for doping Zn into the object wafer.
[Preparatory Steps]
(1) An object wafer 14 , e.g., InP wafer or GaAs wafer, is put into the wafer-storing cavity 2 of the base plank 1 .
(2) The quartz tube 20 is inserted into the pre-heated furnace.
(3) The slider 4 is pulled backward on the base plank 1 to a preparing point and the non-doped capping wafer 13 is affixed at the front of the slider.
(4) The screws 7 are taken out of the cap plate 6 and the slider 4 . The slider 4 is opened by eliminating the cap plate 6 . A diffusion material solid 11 is supplied on the rack 12 . The diffusion material 11 is Znp 2 , Zn 3 P 2 in the case of an InP object wafer. The diffusion material is ZnAs 2 , Zn 3 As 2 or so in the case of a GaAs object wafer.
(5) The cap plate 6 is put upon the frame 5 . The cap plate is fixed to the frame 5 by turning on the screws 7 . The L-end of the manipulating bar 9 is put into the hole 8 of the slider 4 .
(6) The base plank 1 with the slider 4 is inserted into the quartz tube 20 (FIG. 5 ).
[Step 1 (Forming a Vacuum in the Diffusion Room of the Slider]
(7) A vacuum is formed in the reaction tube 20 in the state of FIG. 1 ( 1 ) by a vacuum pump. The outer space of the slider 4 is evacuated by the vacuum pump. The inner space of the slider 4 is also evacuated through the exhaustion hole 3 of the base plank 1 . A desired vacuum of the same pressure is created in both the outer space and the inner space.
(8) The slider 4 is pushed forward by the manipulating bar 9 to a position where the diffusion room 10 deviates from the exhaustion hole 3 and the capping wafer 13 covers the object wafer 14 for isolating the inner space of the slider 4 from the outer space. After the tube is evacuated to a vacuum, hydrogen gas is introduced into the reaction tube for accelerating heat conduction or heat convection for facilitating heating and cooling. The temperature in the diffusion room is denoted by the line αβ in FIG. 4 .
[Step 2 (Rising Temperature Step or Heating Step)]
(9) The base plank 1 , the capping wafer 13 and the object wafer 14 are heated by the furnace at the heating step, where the temperature rises toward the diffusion temperature Td, as shown by the curve βγ in FIG. 4 . The capping wafer 13 discharges the V element gas from the ragged surface for preventing the object wafer 14 from losing the V element atoms at the heating step. The protection by the capping wafer 13 may allows weak occurrence of the V element vacancies. The heating step is shown in FIG. 1 ( 2 ).
(10) The slider 4 is also heated at the heating step for inducing the diffusion material 11 to sublime and to fill the inner space of the slider 4 . The vapor pressure of the V element material rises in the diffusion room 10 . No diffusion occurs at the heating step, since the object wafer 14 is separated from the Zn vapor. The temperature of the wafer 14 is observed by the thermocouple 15 .
[Step 3 (Diffusion Step)]
(11) When the temperature attains to the diffusion temperature Td (T=Td), the slider 4 is pushed forward by the manipulating bar 9 at a spot, where the diffusion room 10 lies above the wafer-storing cavity 2 , as shown in FIG. 1 ( 3 ). This state corresponds to the line γδ on the temperature profile of FIG. 4 . The diffusion room 10 of the slider 4 has been filled with dense Zn compound vapor. The Zn compound vapor comes into contact with the object wafer 14 . Immediately, the Zn diffusion into the wafer 14 starts. Since the diffusion room 10 is narrow, there is no macroscopic flow of gas. The V element vapor is stable in the diffusion room 10 . The desired diffusion depth determines the diffusion time tc.
[Step 4 (Cooling Step)]
(12) When the predetermined diffusion time has passed, the slider 4 is moved on the base plank 1 by the manipulating bar 9 for separating the slider 4 from the object wafer 14 . The Zn diffusion stops at once.
(13) The wafer 14 is cooled in a state separated from the slider 4 , as shown in FIG. 1 ( 4 ). This step corresponds to the line δε in FIG. 4 .
FIG. 5 shows the section of the diffusion apparatus including the surroundings. The base plank 1 , the slider 4 and the manipulating bar 9 are contained in the quartz tube 20 . The quartz tube 20 is not a closed tube. The tube 20 can be evacuated from an end. The tube 20 allows the operation of the manipulating bar 9 from the outer space. The whole of the tube 20 is inserted into a furnace (heater) 21 . The heater 21 consists of a coil resistor 23 and a refractory material 22 supporting the coil resistor 23 . The furnace 21 is an ordinary electric heater which generates Joule's heat by the supply of electric current.
[Embodiment 2: Two Room Type Slider; V Element Room; Single Time Diffusion]
Embodiment 2 aims at preventing the V element from dissociating out of the object wafer during the heating process more effectively than Embodiment 1. For the purpose, Embodiment 2 employs a V element room in the slider 4 instead of the non-doped capping wafer of Embodiment 1. The object wafer is enclosed with higher V element vapor pressure due to the V element room during the heating step than in Embodiment 1. The role of the newly introduced V element room is similar to the capping wafer. When the temperature is raised to Td, the slider is displaced to a spot where the diffusion room coincides with the object wafer for starting the Zn diffusion. When the Zn diffusion finishes, the slider is again displaced for separating the wafer from the Zn atmosphere. Embodiment 2 can suppress the dissociation of the V element by the high V element vapor pressure. Embodiment 2 is more effective for inhibiting the occurrence of V element vacancies in the object wafer.
FIG. 7 shows the steps of the Zn diffusion of Embodiment 2. FIG. 8 is a plan view of the frame of the slider of Embodiment 2. FIG. 9 is a plan view of the slider with the cap plate. A slider 24 has two rooms unlike Embodiment 1. A V element room 30 is newly furnished to the slider 24 instead of the capping wafer. The slider 24 has a frame 25 and a capping plate 26 . The frame 25 has external walls and a partition 28 in the middle. The frame 25 is divided into the V element room 30 and a diffusion room 10 . The rear diffusion room 10 has a rack 34 on the wall for keeping a diffusion material 11 .
The front V element room 30 has a rack 32 on the wall for maintaining a V element solid 31 , which is phosphorus (P) for an InP wafer or is arsenic (As) for a GaAs wafer. The two room type slider 24 covers the object wafer 14 with the V element room 30 during the heating step for suppressing the generation of V element vacancies. The steps of FIG. 7 are explained. FIG. 10 is the temperature profile of the steps measured by a thermocouple 15 .
[Preparatory Steps]
(1) An object wafer 14 , e.g., an InP wafer or a GaAs wafer, is inserted into a wafer-storing cavity 2 of a base plank 1 .
(2) The reaction tube is inserted into the furnace.
(3) The slider 24 is moved to a spot where the V element room 30 coincides with a exhaustion hole 3 of the base plank 1 .
(4) Screws 27 are gotten off and the capping plate 26 is removed from the frame 25 . A diffusion material 11 is supplied to the rack 34 of the rear diffusion room 10 . The diffusion material 11 is ZnP 2 or Zn 3 P 2 for an InP wafer, or ZnAs 2 or Zn 3 As 2 for a GaAs wafer. A V element material 31 is put on the rack 32 of the former V element room 30 . The V element material is red phosphorus (P) for the InP wafer, or arsenic (As) for the GaAs wafer. The following describes an example of employing red phosphorus for an InP wafer as the V element material 31 .
(5) The capping plate 26 is put upon the frame 25 and fixed to the frame 25 by the screws 27 . The L-shaped end of a manipulating bar 29 is put into a hole 33 of the slider 24 .
(6) The whole of the base plank 1 with the slider 24 is inserted into the quartz reaction tube 20 (FIG. 5 ).
[Step 1 (Exhausting the V Element Room (Red Phosphorus Room) into Vacuum]
(7) The slider 24 stays at the spot where the red phosphorus (V element) room 30 lies above the exhaustion hole 3 , as shown in FIG. 7 ( 1 ). A vacuum is created in the reaction tube by a vacuum pump (not shown). The outside of the slider 24 is evacuated directly. The red phosphorus room 30 of the slider 24 is also evacuated through the exhaustion hole 3 . This step corresponds with the temperature line ζη (room temperature) in FIG. 10 .
[Step 2 (Exhausting the Diffusion Room)]
(8) The slider 24 is pushed forward by the manipulating bar 29 to a spot where the diffusion room 10 lies above the exhaustion hole 3 , as shown in FIG. 7 ( 2 ). A vacuum is created in the diffusion room 10 through the exhaustion hole 3 . Thus, both the phosphorus room 30 and the diffusion room 10 are vacuous. Hydrogen gas is introduced into the reaction tube 20 .
The outer space is occupied by hydrogen gas. The temperature takes the line ηθ (room temperature) in this step as shown in FIG. 10 .
[Step 3 (Heating Step or Rising Temperature Step)]
(9) When a vacuum is created in the diffusion room 10 , the snider 24 is pushed forward to a spot where the V element room 30 covers the object wafer 14 which is shown by FIG. 7 ( 3 ). This corresponds to the point θ in the temperature profile of FIG. 10 .
(10) At the step 3 of rising temperature, the furnace overall heats the object wafer 14 , the slider 24 , the V element material 31 and the diffusion material 11 , which is denoted by the curve θτ. The dopant (Zn compound) material 11 is sublimed for making high Zn compound vapor pressure in the diffusion room 10 . The V element material 31 is sublimed for creating high V element vapor pressure in the V element room 30 . The object wafer 14 , which is protected by the high V element vapor pressure in the V element room, is immune from the dissociation of the V element out of the surface. As the temperature rises from θ to τ, the V element (phosphorus here) vapor pressure in the V element room 30 and the Zn compound vapor in the diffusion room 10 pressure rise.
[Step 4 (Diffusion Step)]
(11) When the temperature T rises to Td, the slider 24 is moved forward by the manipulating bar 29 at a spot where the diffusion room 10 covers the wafer 14 , as shown in FIG. 7 ( 4 ). The dopant vapor pressure has risen enough high at Td in the diffusion room 10 . The Zn vapor comes into contact to the wafer 14 . The Zn diffusion starts immediately on the object wafer 14 . The diffusion step corresponds to the line κτ in FIG. 10 . The diffusion time tc should be determined by the purpose of the diffusion.
[Step 5 (Cooling Step)]
(12) When the diffusion time tc has passed, the slider 24 is moved to a spot (FIG. 7 ( 5 )) for separating the diffusion room 10 from the cavity 2 by the manipulating bar 29 . This corresponds to the point κ in FIG. 10 . The diffusion stops at once.
(13) The wafer 14 is cooled from Td to room temperature which is denoted by the line κλ in FIG. 10 .
[Embodiment 3: Three Room Type Slider; Twice Diffusion]
Embodiment 3 aims at diffusing Zn twice into an object wafer on different conditions. The twice diffusion requires three rooms for the slider. The doping processes are different in the kind of the dopants or in the diffusion temperature. Two rooms of the three are diffusion rooms containing Zn compounds. The two diffusion rooms sandwich a V element room. The slider has the diffusion room, the V element room and the diffusion room in turn. An additional capping wafer protects an object wafer during the heating step. The V element room seals the object wafer in the intermediate step between the first (former) diffusion and the second (latter) diffusion. Embodiment 3 employs different means for inhibiting the object wafer from losing the V element. Twice diffusion is realized by Embodiment 3.
But this invention can also be applied to three-time-diffusion or four-time-diffusion which are different in conditions of e.g., different dopants, different times or different temperatures. In general, M-times of diffusion requires 2M rooms (M diffusion rooms and M V element rooms) or (2M−1) rooms (M diffusion rooms and (M−1) V element rooms with a capping wafer).
FIG. 11 shows the sectional view of a slider of Embodiment 3. FIG. 12 is a plan view of the slider without the cap plate. The V element vapor of FIG. 11 can be replaced by a non-doped capping wafer. FIG. 17 shows a version having a bottom capping wafer 57 in the V element room 30 . Detailed steps are not shown in figures, because the steps are obvious from FIG. 1 of Embodiment 1 and FIG. 7 of Embodiment 2. A slider 44 has three rooms formed by a frame 45 and a capping plate 46 . The frame 45 has external walls and two partition walls 52 and 53 . The three rooms are a diffusion room 50 , a V element room 30 and a diffusion room 10 in this order. The capping plate 46 is fixed upon the frame 45 by screws 47 . The rooms 50 , 30 and 10 have open bottoms. The first diffusion room 50 has a rack 56 containing a first diffusion material 51 . The V element room 30 has a rack 55 for storing a V element material 31 . The second diffusion room 10 has a rack 54 for sustaining a second diffusion material 11 . The slider 44 has an end hole 48 for fitting a manipulating bar 49 . The manipulating bar 49 displaces the slider 44 in the longitudinal direction upon a base plank 1 .
The slider 44 has a non-doped capping wafer 13 fixed at the front end. The non-doped capping wafer 13 covers the cavity 2 for suppressing the V element from escaping out of the surface of an object wafer 14 at the heating step. The capping wafer 13 can also be replaced by a V element room in the slider. In the variation, the slider would have four rooms.
FIG. 13 denotes the temperature profile of the double diffusion of Embodiment 3. Individual steps are explained;
[Preparatory Steps]
(1) An object wafer 14 is put in the cavity 2 on the base plank 1 .
(2) The reaction tube (e.g., quartz tube) is installed into the furnace.
(3) The slider 44 is pulled back to a point where the first diffusion room 50 stays above the exhaustion hole 3 by the manipulating bar 49 .
(4) The screws 47 are taken off the slider 44 . The cap plate 46 is removed from the frame 45 . A second diffusion material 11 is supplied on the rack 54 in the second diffusion room 10 . A V element material 31 is put on the rack 55 in the middle V element room 30 . Like former embodiments, the V element material is red phosphorus for an InP object wafer or arsenic (As) for a GaAs object wafer. A first diffusion material 51 is laid on the rack 56 of the first diffusion room 50 .
(5) The capping plate 46 is fixed upon the frame 45 by the screws 47 . The end of the manipulating bar 49 is inserted into the end hole 48 of the slider 44 .
(6) The whole of the base plank 1 is inserted into the quartz tube 20 .
[Step 1 (Exhaustion of First Diffusion Room·V Element room·Second Diffusion Room)]
(7) The whole reaction tube is exhausted into a vacuum. The outer space of the slider 44 is evacuated. A vacuum is created also in the first diffusion room 50 through the exhaustion hole 3 .
(8) The slider 44 is pushed forward to a spot where the V element room 30 lies upon the exhaustion hole 3 . The V element room 30 is exhausted through the exhaustion hole 3 .
(9) The slider 44 is further pushed forward to another spot where the second diffusion room 50 lies upon the exhaustion hole 3 . The second diffusion room 50 is evacuated through the exhaustion hole 3 . Thus, all the rooms 50 , 30 and 10 are evacuated into a vacuum. The slider 44 is slightly displaced for isolating the diffusion room 10 from the atmosphere in the reaction tube 20 . Three rooms 50 , 30 and 10 are isolated. Hydrogen gas is supplied into the reaction tube, which corresponds to the line μν in FIG. 13 .
[Step 2 (Step of Rising Temperature or Heating Step)]
(10) The slider 44 is carried by the manipulating bar 49 to a spot where the non-doped capping wafer 13 shields the object wafer 14 which is shown in FIG. 11 . The furnace heats the whole of the reaction tube including the base plank, the slider 44 and the wafers 14 and 13 . This corresponds to the curve νζ in FIG. 13 . The capping wafer 13 protects the wafer 14 during the rising temperature step.
[Step 3 (First Diffusion Step)]
(11) When the temperature rises up to Td (T=Td), the manipulating bar 49 conveys the slider 44 to a spot where the wafer 14 is covered by the first diffusion room 50 which has high vapor pressure of the Zn compound. The wafer 14 adsorbs the dopants (the Zn compound). Zn atoms diffuse from the surface into the object wafer. The diffusion corresponds to the line ζο in FIG. 13 . The diffusion time t 1 is predetermined in accordance with the purpose.
[Step 4 (Transient Cooling)]
(12) When the predetermined diffusion time t 1 has elapsed, the slider 44 is further moved to a spot where the V element room 30 shields the object wafer 14 . The temperature is decreased from Td 1 to Td 2 by reducing the heater power. The transitory cooling is denoted by the line πο in FIG. 13 . At the transitional step between Td 1 to Td 2 , the V element vapor pressure protects the wafer 14 from the degeneration due to the V element dissociation in the V element room 30 .
[Step 5 (Second Diffusion Step)]
When the temperature falls to Td 2 , the slider 44 is moved forward to a spot where the wafer lies under the second diffusion room 10 . The high dopant vapor pressure begins the second diffusion immediately in the second diffusion room 10 . The Zn diffusion lasts for t 2 . The diffusion corresponds to the line πρ in FIG. 13 .
[Step 6 (Cooling Step)]
(14) When t 2 elapses, the slider 44 is separated from the cavity 2 by the manipulating bar 49 . The diffusion stops at once. The temperature of the furnace is decreased along the line ρσ in the temperature profile of FIG. 13 .
Embodiment 1 is further explained in more detail. The Zn diffusion is carried out by the slider of M=1 which is shown in FIG. 1, FIG. 2 and FIG. 3 . Since M=1, the slider has only the single room 10 . The inner space of the slider 4 has a 30 mm width, a 30 mm length and a 20 mm height. The volume of the inner space is 18 cm 3 . A non-doped InP capping wafer 13 with an inner rugged surface is fitted at the front end of the slider 4 . Zn 3 P 2 (4 mg) is put on the rack 12 of the diffusion room 10 . Two different InP wafers {circle around ( 1 )} and {circle around ( 2 )} are allotted for object wafers for surveying the influence of the carrier density.
InP wafer {circle around ( 1 )} . . . Sn doped InP (carrier density: 1×10 18 cm −3 )
lnP wafer {circle around ( 1 )} . . . non-doped InP (carrier density: 5×10 15 cm −3 )
An object wafer is put into the cavity 2 . The frame 5 is put on the base plank 1 . The capping plate 6 is fixed to the frame 5 by the screws 7 . The end of the manipulating bar 9 is coupled into the hole 8 of the slider 4 . The base plank 1 is inserted into the quartz tube. The quartz tube is exhausted into a vacuum of 1×10 −6 Torr. The slider 4 is carried for coinciding the diffusion room 10 with the exhaustion hole 3 . A vacuum is created in the diffusion room 10 . Hydrogen gas with good heat conduction is introduced into the quartz tube. The quartz tube is installed into the furnace.
The furnace heats the base plank 1 , the slider 4 , the wafer 14 and so on. The temperature of the object wafer 14 is monitored by the thermocouple 15 . When the temperature measured by the thermocouple is stable at 580° C., the slider 4 is pushed forward for sending the diffusion room 10 just above the object wafer 14 . The displacement brings the wafer into contact with the Zn 3 P 2 vapor. Zn atoms are diffused into the object wafer 14 at 580° C. for the determined diffusion time. When the predetermined diffusion time has elapsed, the slider is separated from the wafer 14 by the manipulating bar 9 . The diffusion finishes without delay. The wafer 14 is cooled in the state isolated from the diffusion room 10 . The present invention is far superior to the closed tube method in the controllability.
The base plank 1 is plucked out from the quartz tube. The object wafer 14 is taken out of the wafer-storing cavity 2 . The object wafer is cleaved for revealing the sectional sides. Then, the wafer is etched by an etchant of potassium ferrocyanide (K 4 [Fe(CN) 6 ])+potassium hydroxide (KOH) which has different etching speeds for n-type InP and p-type InP. The diffusion depth is measured by observing the etched sides of the wafer by a microscope.
The diffusion depth is determined by the average length of the Zn invading into the InP crystal. However, the initial electron density is different for various n-type InP crystals. The measured diffusion length depends upon the initial electron density of the n-type InP. The density of Zn atom varies slowly in the direction of thickness. It is difficult to determine the limit of the Zn distribution as the diffusion depth. Then, the line which equalizes the electron density n to the hole density p is defined as a pn-junction. The diffusion depth is defined as the length from the surface to the pn-junction (p=n). If the initial electron density is lower, comparatively lower doping of Zn can make a deeper pn-junction (p=n). If the initial electron density is higher, the same dopant density makes a shallower pn-junction.
Since the InP wafer {circle around ( 1 )} having higher initial electron density of n=10 18 cm −3 , the pn-junction is defined as the line on which the Zn density is equal to 10 18 cm −3 (p=n).
The wafer {circle around ( 2 )} having lower initial electron density of n=5×10 15 cm −3 , since it is not doped with n-type dopant intentionally. The pn-junction is the interface on which the hole density is equal to 5×10 15 cm −3 . The diffusion depth is determined as the depth of the pn-junction.
The diffusion depth is measured for different diffusion times for both the wafers {circle around ( 1 )} and {circle around ( 2 )}. FIG. 6 shows the result of the measurement of the diffusion depth. The abscissa is the root of the diffusion time. The ordinate is the measured diffusion depth (μm). Black rounds denote the diffusion depths of the non-doped InP wafer {circle around ( 2 )}. 4 minute diffusion gives about 5 μm of diffusion depth. 10 minutes of diffusion make about an 8 μm diffusion depth. A 10 μm diffusion depth takes about 18 minutes for the non-doped wafer {circle around ( 2 )}. The diffusion depth is in proportion to the root of the diffusion time. Black triangles denote the diffusion depths for the Sn-doped n-InP wafer {circle around ( 1 )} with higher initial electron density. 5 minutes of diffusion give a 1.8 μm diffusion depth. 10 minute diffusion makes a 2.3 μm diffusion depth. 28 minute diffusion obtains a 4.2 μm depth. The diffusion depth is in proportion to the root of the diffusion time also for the highly doped InP wafer {circle around ( 1 )}. The result shows that the diffusion time exactly controls the diffusion depth. In this invention, the wafer comes into contact to the Zn compound vapor at the beginning of the diffusion step and the wafer is separated from the Zn compound vapor at the cooling step by the operation of the slider. No extra diffusion occurs at the heating step and the cooling step. The control of the start and the stop of diffusion is far more rigorous in the present invention than the closed tube method. The examples use 1-inch diameter wafers. This invention can also apply to wafers of arbitrary sizes. | An LPE (Liquid Phase Epitaxy) apparatus is diverted to a Zn-diffusion apparatus for diffusing Zn into III-V group compound semiconductor. The Zn-diffusion apparatus comprises a base plank extending in a direction, having a wafer-storing cavity for storing an object wafer and an exhaustion hole for exhaling gases, a slider having a frame and a cap plate for attaching to or detaching from the frame, the frame having serially aligning M rooms with an open bottom and a rack being separated from each other by (M−1) partition walls, a manipulating bar for sliding the slider upon the base plank forward or backward in the direction, a tube for enclosing the base plank and the slider and for being capable of being made vacuous, a heater surrounding the tube for heating the slider, each rack of the rooms being allocated with a Zn-diffusion material and a V element material (or a non-doped capping wafer) in turn for aligning the rooms into repetitions of a V element room and a diffusion room. The V element room or the capping wafer covers and protects the object wafer during the heating step. During the diffusion step, the diffusion room covers the object wafer for diffusing Zn into the wafer. | 7 |
BACKGROUND OF THE INVENTION
The present invention relates to wood pulping and papermaking. Specifically, the invention relates to a process and corresponding apparatus for more efficiently producing wood pulp from a batch type digester.
Each digester in a pulp mill represents an enormous capital investment for utility support and environmental protection. It is of paramount importance, therefore, that pulp production from each digester be sustained at the greatest possible rate consistent with the wood species used and the pulp characteristics desired. Although several types of continuous digesters are well developed for producing certain kinds of pulp, the batch cycled digester remains in wide commercial use due to its adaptability to the widest range of products and controllability for uniform quality of those products. In terms of production rate, however, a large percentage of the batch digester production cycle, from batch-blow to batch-blow, is spent in the loading and preheating intervals. Since total cycle times run in the range of 60 to 185 minutes, any reduction of only a few minutes is significant when it is considered that most pulp mills operate continuously and the saving will be repeated several times a day with the end result of more product per unit of time.
Wood pulping digesters of the batch cycled type are normally elongated, vertical axis pressure vessels having a filler neck of reduced sectional area at the top and a product blow line from the bottom. A capping valve in the filler neck is selectively opened to admit a wood chip charge into the pressure vessel and closed to secure steam pressure for the designated chip cooking time.
According to a prior art practice, as chips enter the vessel from the filler neck, chip packing steam is admitted to the upper portions of the pressure vessel at a skewed angle to the vessel axis for the two-fold purpose of 1) leveling the chip sectional distribution as the chip charge accumulates and 2) heating and presteaming of the chips as the charge accumulates.
As the top down directed steam flow distributes the incoming chip charge, air drawn down through the digester filler neck with the chips is discharged through the digester circulation screen and/or through vent taps at the bottom of the digester.
Presteaming wood chips is known to reduce knot and shive generation by improving the impregnation of liquor into the chips, which increases the digester screened yield. Also, steam packing plus presteaming reduces the time to temperature, the time at temperature, alkaline charge, and eliminates false digester pressure.
Uniform sectional distribution of the chips makes it possible for the cooking liquor to circulate evenly within the digester for uniform chip penetration resulting in a high quality pulp having few shives and knots.
Bottom up directed steam flow during the chip packing and heating interval has previously been considered unsafe as impossible to control. Prior experiences and attempts have resulted in violent chip discharges through the filler neck.
It is, therefore, an object of the present invention to increase the productivity of batch cycled wood pulp digesters.
Another object of the present invention is to increase the mass of wood chips loaded into a digester for each cooking cycle.
Also an object of the present invention is to reduce the variations in wood chip mass charged into a digester between successive cooking cycles.
A further objective for the present invention is to reduce the required presteaming time for a digester chip charge.
Another objective of the present invention is to reduce the chemical alkali charge in which a chip batch is cooked.
A still further object of the present invention is to reduce the digester cycle time by reducing the time to temperature and the time at temperature.
Another objective of the present invention is to increase screened yield of a digested chip batch by knot and shive reduction.
Another object of the present invention is to improve the consistency of chip delignification as is represented by a reduction in the standard deviation of measured Kappa Number values.
Additional objects of the present invention are to improve pulp uniformity and strength by reducing the alkali charge and cooking temperature.
Another object of the present invention is the reduction of recovery boiler solids, pulp dirt, and bleach plant chemical consumption.
SUMMARY OF THE INVENTION
With regard to the foregoing and other objects and advantages, the present invention is directed to a digester steam packing/presteaming sequence which, in accordance with its more general aspects, comprises loading chips into a digester to accumulate a preliminary chip mass in the digester sufficient to restrain and condense approximately 1/3 to 1/2 of the maximum flow rate of steam directed into the accumulated chips in the bottom of the digester. With the preliminary chip mass in place, steam flow is then initiated and increased proportionately to the chip bed accumulation, preferably at the maximum rate which is sufficient to insure full condensation of the steam flow by the chip bed mass.
In accordance with one exemplary embodiment of the invention, a digester packing/pre-steaming sequence is provided for a 4,500 ft 3 to 6,500 ft 3 digester whereby substantially all digester steam flow is terminated while the first 5 to 13 green tons (G.T.) of chips are charged. With a minimum chip charge in the digester, steam flow is started from the bottom at a rate of 20,000 to 30,000 pounds per hour.
As the chip charge accumulates, the steam flow rate is increased until reaching a rate of about 70,000 pounds per hour. Such steam flow rate increase is modulated by the rate of chip condensation. The quantity of chips in the digester preferably should be capable of condensing all the steam added to the digester from the bottom. Also, the chip mass in the digester must be adequate to prevent the steam force from blowing chips out of the digester.
A temperature sensor is positioned in the chip charging chute as a source of a steam valve control signal. Should steam break through the chips and exit the digester through the filler neck, the temperature sensor will detect the significant temperature rise from the steam and shut the steam supply valve.
For digesters in the size range of 4500 to 6500 ft 3 , the steam flow rate in pounds per hour is preferably modulated according to the relationship:
Steam Flow, lb/hr=(Chip Weight, G.T. +4.79)÷(0.000896)
BRIEF DESCRIPTION OF THE DRAWING
The single FIGURE of the drawing illustrates a piping and control schematic of the invention physical arrangement.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the single figure of the drawing, there is indicated at 10 a 150 psia rated, elongated, cylindrical pressure vessel exemplary of an apparatus for practicing the present invention. The upper end of the vessel 10 is closed by a domed end-cap having a filler neck cylinder 12 of reduced circular section, usually 2 ft. to 4 ft diameter, projecting axially therefrom. At the bottom end, the vessel is closed by a generally funneled configuration having a blow-line conduit 16 issuing substantially along the funnel axis and flow controlled by a motor valve 17.
A quantity of wood chips or other appropriate cellulosic fiber source is charged into the vessel 10 interior through a chip chute or channel 14 past a capping valve 20 which seals at least 150 psig steam pressure within the vessel 10. Preferably, a chip weight or volume flow meter 24 is disposed in the chip supply channel 14 as the source of a chip flow rate related signal from the meter transducer 26 to a process controller 30.
Also disposed within the chip supply channel 14 is a temperature sensor 22 responsive to temperature within the channel of the character that is indicative of steam escaping from the vessel 10 interior. Sensor 22 is constructed to transmit a signal to the controller 30 in the event of steam escape from the vessel 10 into the chip supply channel.
Operatively connected to the upper or bottom end of the vessel 10 are one or more liquor lines 38 controlled by respective valves 32, preferably remote operated valves. These liquor supply conduits are connected to admit processing chemical onto a chip charge such as those blends characterized by the industry lexicon as white and black liquor.
In internal flow communication with the upper portion of the filler neck 12 below the capping valve 20 is a turpentine relief conduit 40 which extracts valuable product vapors such as turpentine for condensation and sale. Such extraction is controlled by the two valves 34 and 36. Steam blow-back conduit 35, controlled by valve 36, provides a source of steam pressure to expel the chips, fines and fiber that collect on the separator strainer located in conduit 40.
Steam conduit 18 may be alternatively supplied with medium (approximately 160 psig) and low grade (approximately 60 psig) steam via conduits 25 and 28 controlled by valves 27 and 29, respectively. Motor valves 27 and 29 preferably are operatively responsive to the controller 30 and signals from the chip meter transmitter 26 and the supply channel temperature sensor 22. It should also be understood that the controller 30 may be responsive to signal sources other than or additional to those of transmitter 26 and temperature sensor 22.
As an overriding steam control concern, preheating and distribution steam temperature should not exceed 400° F. out of concern for the resulting pulp quality and strength. Wood cellulose deteriorates rapidly above about 400° F. Normally, digester steam temperatures are in the range of 330° F. to 360° F.
In the operative context of the aforedescribed equipment, a chip cooking cycle according to a preferred embodiment of the invention proceeds substantially along the following event sequence.
With the valves 17, 27, 29, 32, 34 and 36 closed, capping valve 20 is opened to admit a measured chip flow rate into the digester 10. Upon the internal accumulation of a lower threshold chip quantity to the level A, either or both steam valves 27 or 29 are opened to admit an initial steam flow rate of about 1/3 to 1/2 of the full flow rate.
A "full" steam flow rate to a particular digester is a highly variable value concluded by many factors. An initial or primary design factor is the volumetric size of the digester. However, the value may also be influenced by the total digester volume distributed among a multiplicity of individual digesters in a pulp plant as a function of the steam plant generation capacity. More particularly, the full steam flow rate available to a digester will depend on the size of the steam generation plant, the total volumetric steam demand from the supply system at the moment and the line capacity to carry that demand. All of these factors considered, a reasonably reliable full flow rate to a particular digester will be provided as a function of the digester volume.
It is not believed necessary to know precisely the physical location of the chip level B. Actual practice of the invention only requires that a sufficient chip plug depth is in place when the steam valves are opened to contain and condense the initial steam flow rate. By "sufficient" chip plug is meant that a minimum or threshold chip mass relationship to the initial steam flow rate is present to: (1) prevent chips that form the plug from being blown from the digester through the filter neck; (2) prevent steam from short-circuiting the chip plug by channeling through or around it; (3) prevent a fluidization or suspension of the accumulating chip plug and, (4) entirely condense the steam-input.
This procedure and flow sequence is to be understood in the context of a continuously transitioned material flow and blending process. When chip flow into the digester begins, it continues at a substantially full flow rate until the full chip charge is in the digester. Steam flow into the bottom of the digester is coordinated with this continuous chip in-flow. Accordingly, at a known chip flow rate (weight or volume per unit of time), the initial steam flow rate begins at the appropriate moment after chip in-flow begins. There normally is no hesitation or change in the chip in-flow rate as the steam flow starts. The chip bed continues to steadily accumulate the combined mass of the steam and the chips since all the steam is condensed upon the chips.
As the chip bed grows in mass, the steam flow rate is correspondingly increased to continue the full condensation, non-channeling and non-fluidizing strategy until the maximum steam flow capacity is attained or all the chips of a charge are in the digester.
For digesters in the size range of 4,500 ft 3 to 6,500 ft 3 , a chip charge of 5 to 13 tons of "green" (50% moisture content) chips will restrain and condense an initial steam flow of about 20,000 to 30,000 lb/hr. Of course, a "trickle" flow of steam may be started with initial chip delivery but in most pulping facilities, the minimum chip quantity is deposited in the digester with such rapidity that trickle flow regulation of steam up to a containable 1/3 to 1/2 flow rate is rarely justified. In either case, steam flow is then increased at a steady or ramped rate corresponding to the chip influx rate and consistent with the functional result of condensing all steam injected into the vessel bottom by conduit 18 within the accumulating chip bed. For digesters in the 4,500 ft 3 to 6,500 ft 3 range, the controller 30 may be programmed to increase the steam flow along with the chip bed increase approximately according to the following relationship:
Steam Flow, lb/hr=(Chip Weight, GT+4.79)÷(0.000896)
This relationship is suitable for a full flow rate of about 70,000 lb/hr. into 52 to 60 GT of chips and continues until all chips for a charge are in the digester or when the designated presteaming period is complete, usually a period of less than 3 minutes.
As the chips and steam combine, the chip surface level B rises up the digester height followed by a plug zone Y of chips above a steam saturated chip face C. Below the level B, which is actually a transitional zone, the chips are steam condensate saturated and are above the temperature of 220°. Under these conditions, the chips are soft, plastic, pliable and readily compacted by the weight of the chip charge overburden.
Accordingly, both compaction and presteaming of the chip charge are accomplished simultaneously.
During this combined chip presteaming and steam packing period, the temperature sensor 22 is calibrated to signal the presence of steam above the capping valve 20. In such an event, the appropriate signal is transmitted to the controller 30. Responsively, other control programs are overridden in favor of a valve closure command to steam valves 27 and 29 to immediately terminate steam flow from the conduit 18.
With the chip charge and presteaming period complete, the steam valves 27 and 29 are closed as is the capping valve 20. In this state, the relief valve 34 and liquor valve 32 are opened to deliver a complete liquor charge into the chip bed.
Having received a complete liquor charge, the valve 32 is closed and the low pressure steam valve 29 and later, medium pressure steam valve 27 are opened to raise the charged digester to the designated cooking temperature and pressure whereupon all valves except 34 are closed for the transpiration of the designated cooking time. When the cook is complete, the blow valve 17 is opened to expel the digester contents explosively.
Having described the preferred embodiments of my invention, | A batch digester loading method is described wherein a flow stream of steam enters the digester near the bottom thereof as a flow stream of wood chips enters through the top filler neck. Steam flow begins in the bottom portion of the digester at an initial, reduced flow rate after a minimum chip mass is accumulated. Steam flow is thereafter increased at a rate proportional to the inflow rate of chips. | 3 |
CLAIM FOR PRIORITY
[0001] This application claims the benefit of Taiwan Patent Application No. 100124605, filed Jul. 12, 2011, and Taiwan Patent Application No. 101111384, filed Mar. 30, 2012, the subject matters of which are incorporated herein by reference.
CROSS-REFERENCES TO RELATED APPLICATIONS
[0002] Not applicable.
BACKGROUND OF THE INVENTION
[0003] 1. Field of the Invention
[0004] The present invention relates to a fluorescent layer and its preparation method and uses. In particular, the present invention relates to a fluorescent layer useful in light emitting diodes and its preparation method.
[0005] 2. Descriptions of the Related Art
[0006] With the awareness of saving energy and protecting the environment, white light emitting diodes (LEDs) have become the most anticipated emerging product and have gradually replaced traditional lighting equipments because of advantages including a smaller size (in response to the trend of miniaturization), low power consumption (one eighth to one tenth of conventional light bulbs, and half of fluorescent lamps), a long lifespan (more than 100,000 hours), low heat generation (low heat radiation), and excellent response time (capable of high frequency operation). White LEDs can solve many problems that incandescent bulbs could not solve, and thus, have become a new hope of lighting in the 21 st century. In addition, the white LED is a “green lighting source” because it is both power-saving and eco-friendly.
[0007] White LEDs that were developed in the past consisted of a plurality of LEDs with various light emitting wavelengths. However, such a device is limited in application to light emitting devices requiring high luminance due to a large volume, poor luminous efficiency and uneven color mixing. In principle, current white LEDs consist of a single wavelength light source (LED chip) and at least one fluorescent material excitable by the light source. The fluorescence emitted from the excited fluorescent material is mixed with the light emitted from the light source (which is not absorbed by the fluorescent material) to form white light. For the structure of current white LEDs, the fluorescent material is generally mixed with a packaging material such as an epoxy resin to form a package, and then, a light source is covered with the package, i.e., forming a fluorescent layer on the light source to provide the white LED.
[0008] Nonetheless, the above light emitting device, when used for a time period, often has the problem of aging (etiolation) because the epoxy resin therein is over-crosslinked due to the absorption of ultraviolet light or heat generated by the diode. This aging problem lowers the luminous efficiency of the light emitting devices significantly. In addition, the fluorescent material in the light emitting layer also has effects such as heat exhaustion or thermal quenching as the temperature increases.
[0009] The industry has improved the heat dissipation performance of the light emitting device to lower the extent of heat exhaustion of the fluorescent material and to slow down the aging (etiolation) of the epoxy resin. U.S. Pat. No. 7,361,938 discloses a fluorescent plate member to improve the problem of heat dissipation, wherein the fluorescent plate is prepared directly by thermally pressing YAG fluorescent powders at about 1700° C. The fluorescent plate provided by the foregoing means may prevent the fluorescent resin layer from aging and lower the light scattering, but it requires a large amount of fluorescent material and repeated high temperature thermal treatments, thus, increasing the cost.
[0010] Based on the needs mentioned above, the present invention provides another fluorescent layer and the preparation method thereof, which can improve the heat dissipation of LED, and can rid of the aging (etiolation) problem because the fluorescent layer of the present invention is free of an organic resin. The final product exhibits characteristics of stable light emission, a long lifespan and high durability. Moreover, the present invention uses a cheaper calcining powder, which can be sintered at a lower temperature, to reduce the manufacturing cost and lower the process difficulty, thus, overcoming many problems encountered in the prior art.
SUMMARY OF THE INVENTION
[0011] An objective of the present invention is to provide a fluorescent layer, comprising a fluorescent material and a calcining material, wherein the fluorescent material is in an amount ranging from about 5 wt % to about 95 wt % based on a total weight of the fluorescent layer.
[0012] Another objective of the present invention is to provide a sapphire fluorescent plate, comprising a sapphire substrate and a fluorescent layer as described above on the sapphire substrate.
[0013] Still another objective of the present invention is to provide a method for manufacturing a fluorescent layer, comprising mixing a fluorescent material and a calcining material to form a green thin layer, wherein the fluorescent material is used in an amount ranging from about 5 wt % to about 95 wt % based on the total weight of the green thin layer; and performing a thermal treatment on the green thin layer at a temperature around the eutectic point of the calcining material.
[0014] Yet another objective of the present invention is to provide a method for manufacturing a sapphire fluorescent plate, comprising providing a sapphire substrate; mixing a fluorescent material and a calcining material to form a green thin layer, wherein the fluorescent material is used in an amount ranging from about 5 wt % to about 95 wt % based on the total weight of the green thin layer; and placing the green thin layer on the sapphire substrate and performing a thermal treatment on the green thin layer and sapphire substrate, wherein the thermal treatment is performed at a temperature around the eutectic point of the calcining material.
[0015] Yet still another objective of the present invention is to provide a light emitting device, comprising an excitation light source and a fluorescent layer or a sapphire fluorescent plate as described above.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is a schematic drawing of a fluorescent layer according to one embodiment of the present invention;
[0017] FIG. 2 is a schematic drawing of a sapphire fluorescent plate according to one embodiment of the present invention;
[0018] FIG. 3 is a schematic drawing of a light emitting device according to one embodiment of the present invention;
[0019] FIG. 4 is a schematic drawing of a light emitting device according to another embodiment of the present invention;
[0020] FIG. 5 is a luminescence spectrum of the light emitting device I according to the example of the present invention; and
[0021] FIG. 6 is a transformed CIE coordinate diagram of the light emitting device I according to the example of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0022] Hereinafter, some embodiments of the present invention will be described in detail with reference to the appended drawings. However, without departing from the spirit of the present invention, the present invention may be embodied in various embodiments and should not be limited to the embodiments described in the specification and drawings. Furthermore, for clarity, the size of each element and each area may be exaggerated in the appended drawings and not depicted in actual proportion. Unless it is additionally explained, the expressions “a,” “the,” or the like recited in the specification of the present invention (especially in the claims) should include both the singular and the plural forms.
[0023] FIG. 1 is a schematic drawing of the fluorescent layer according to one embodiment of the present invention. The fluorescent layer 1 comprises a fluorescent material 12 and a calcining material 11 . The calcining material 11 is the structural matrix. The fluorescent material 12 is dispersed in the calcining material 11 , and preferably dispersed uniformly therein. The phrase “the calcining material 11 is the structural matrix” indicates that the calcining material 11 is the matrix to support the 3D structure of fluorescent layer 1 . In addition to the distribution shown in FIG. 1 , the fluorescent material 12 may be also dispersed in the calcining material 11 in for example a rhombus stagger or twill manner.
[0024] The calcining material useful in the present invention comprises a first component and a second component, wherein the first component may be selected from any suitable transparent ceramic material, for example aluminum oxide (Al 2 O 3 ), silicon dioxide (SiO 2 ), and a combination thereof A combination of aluminum oxide and silicon dioxide is preferred to be used as the first component. The second component is selected to be able to destroy some of the bonding structure of the first component (i.e., ceramic material) to lower the melting point of the first component and then the thermal treatment temperature of the materials, and thus, provides the fluxing effect. The second component comprises barium oxide, and may optionally comprise another substance other than barium oxide for replacing a portion of barium oxide. The other substance may be for example oxides of other alkaline earth metals (i.e., alkaline earth metals other than barium), such as magnesium oxide (MgO), calcium oxide (CaO), strontium oxide (SrO), and any combinations thereof The substitution amount of the other substance may be adjusted by the desired fluxing effect, application of final product and manufacturing cost, and usually does not exceed about 50 mole % of barium oxide. In some embodiments of the present invention, a(BaO)•Al 2 O 3 •b(SiO 2 ) (2≦a≦3 and 8≦b≦12) is used as the calcining material. When the second component of the calcining material further comprises the other substance, the total amount of barium oxide and other substance should allow each component in the calcining material to be in the ratio described above. For example, when the second component consists of barium oxide and calcium oxide, the calcining material may be a((1−y)BaO{grave over ( )}yCaO)•Al 2 O 3 •b(SiO 2 ) (0<y≦0.5, 2≦a≦3 and 8≦b≦12), and when the second component consists of barium oxide, calcium oxide and magnesium oxide, the calcining material may be a((1−w−z)BaO, wCaO, zMgO)•Al 2 O 3 •b(SiO 2 ) (0<w+z≦0.5, 2≦a≦3 and 8≦b≦12), and so on. In the examples below, a(BaO)•Al 2 O 3 •b(SiO 2 ) (2≦a≦3 and 9≦b≦11) is used as the calcining material.
[0025] Commercially available fluorescent materials, for example, nitrogen oxide fluorescent material, or rare earth garnet fluorescent material, may be used with the calcining material to provide the fluorescent layer in the present invention. According to one embodiment of the present invention, the rare earth garnet fluorescent material, for example M 3−x Al 5 O 12 :Ce x (0<x≦0.5), wherein M is Y, Lu or a combination thereof, is used.
[0026] According to Beer's Law, the fluorescence efficiency is determined by the amount of fluorescent material and the thickness of the fluorescent layer, and the desired fluorescence effect may be provided by adjusting the two factors. In the present invention, the fluorescent material is generally in an amount ranging from about 5 wt % to about 95 wt %, preferably about 20 wt % to about 70 wt %, and more preferably about 30 wt % to about 50 wt %, based on the total weight of the fluorescent layer. If the amount of fluorescent material is too low, a sufficient and desirable luminous effect may not be provided, and if the amount is too high, too many pores are generated in the fluorescent layer to influence the luminous efficiency. The thickness of the fluorescent layer is generally controlled to range from about 0.05 mm to about 2 mm, and preferably about 0.2 mm to about 1.5 mm. If the thickness of the fluorescent layer is too thin, the fluorescent layer may be broken easily during preparation, and if the thickness thereof is too thick, it may fail to achieve the need for miniaturization. In addition, in some embodiments of the present invention, a fluorescent layer that is thicker and larger in size may be prepared, and then, the layer is thinned to the desired thickness by grinding and is cut into an appropriate size for later use.
[0027] The present invention also provides a method for manufacturing a fluorescent layer, comprising mixing a fluorescent material and a calcining material to form a green thin layer; and performing a thermal treatment on the green thin layer. The species, amounts and variations of the fluorescent material and calcining material useful in the present invention are as described above. Preferably, the fluorescent material is M 3−x Al 5 O 12 :Ce x (0<x≦0.5), wherein M is Y, Lu or a combination thereof and the calcining material is a(BaO)•Al 2 O 3 •b(SiO 2 ) (2≦a≦3 and 8≦b≦12). In one embodiment of the present invention, a(BaO)•Al 2 O 3 •b(SiO 2 ) (2≦a≦3 and 9≦b≦11) is selected as the calcining material. According to the method of the present invention, the fluorescent material is used in an amount ranging from about 5 wt % to about 95 wt %, preferably about 20 wt % to about 70 wt % and more preferably about 30 wt % to about 50 wt %, based on the total weight of the fluorescent layer.
[0028] The method for forming the green thin layer by mixing the calcining material and the fluorescent material is not particularly limited, and the methods of dry pressing or wet slurry forming may also be used. When the wet forming manner is applied, the calculation of the amount of the fluorescent material is based on the dry weight of the green thin layer (i.e., not containing the weight of the solvent or dispersant). In addition, for increasing the structural strength of the green thin layer, a small amount of an adhesive may be added optionally, for example poly(ethylene glycol). Poly(ethylene glycol) can be decomposed and escapes at about 350° C. and will not affect the subsequent processes and characteristics of the product.
[0029] The calcining material used in the method of the present invention is not only commercially available, but also prepared through the reaction of precursors. For example, the calcining material may be prepared by providing a precursor mixture, and then performing a thermal treatment on the precursor mixture at a temperature above the thermal decomposition temperature of each component in the precursor mixture, i.e., solid state reaction.
[0030] In the above solid state reaction, the precursor mixture comprises a first precursor component and a second precursor component. The first precursor component is selected from a group consisting of aluminum oxide, a precursor of aluminum oxide, silicon dioxide, a precursor of silicon dioxide, and combinations thereof The precursor of aluminum oxide refers to one that can provide aluminum oxide by heating, such as aluminum-containing hydroxides, aluminum-containing organic acid salts, or aluminum-containing inorganic acid salts; specific examples include aluminum hydroxide, aluminum citrate, aluminum acetate, aluminum nitrate, and aluminum carbonate. The precursor of silicon dioxide refers to one that can provide silicon dioxide by heating, such as silanes; specific examples include tetraethoxysilane (TEOS) and dimethoxydimethylsilane. The second precursor component comprises a precursor of barium oxide that can be provided by heating, such as barium hydroxide, barium citrate, barium acetate, barium nitrate, and barium carbonate. In some embodiments, the second precursor component further comprises a precursor of another substance, such as the precursor of an oxide of other alkaline earth metals (i.e., the one other than barium). The precursor of an oxide of other alkaline earth metals refers one that can form an oxide of alkaline earth metal by heating, such as alkaline earth metal-containing hydroxides, alkaline earth metal-containing organic acid salts, or alkaline earth metal-containing inorganic acid salts, and the specific examples are such as strontium hydroxide, calcium hydroxide, strontium citrate, calcium citrate, strontium acetate, calcium acetate, strontium nitrate, calcium nitrate, strontium carbonate, and calcium carbonate. In some embodiments of the present invention, the first precursor component comprises aluminum oxide and silicon dioxide, while the second precursor component is barium carbonate. The composition and amount of the precursor mixture used in the present invention are basically determined by the desired calcining material, and the illustration and variations thereof are as described above.
[0031] After obtaining the precursor mixture, a thermal treatment is performed on the precursor mixture at a temperature above the thermal decomposition temperature of each component in the precursor mixture (i.e., the first component and the second component) to obtain a calcining material. The “thermal decomposition temperature” refers to the lowest temperature allowing for each precursor component to be reacted under heat to form a ceramic phase which is stable at a high temperature and generally in oxide form. For example, when the precursor component is barium carbonate, the thermal decomposition temperature is the temperature in which barium carbonate is thermally decomposed to barium oxide. If the precursor component is already in a stable ceramic phase at high temperature, for example aluminum oxide, its thermal decomposition temperature can be neglected. Persons with ordinary skill in the art, after reviewing the context herein, may select an appropriate condition for performing a thermal treatment on the precursor mixture based on their knowledge and the species of the precursor component. For example, the thermal treatment may be performed on the precursor mixture in an air atmosphere at a temperature ranging from about 750° C. to about 950° C.
[0032] According to the method for manufacturing a fluorescent layer of the present invention, after obtaining a green thin layer, a fluorescent layer is obtained by performing a thermal treatment on the green thin layer; wherein the thermal treatment is performed at a temperature around the eutectic point of the calcining material. In other words, the temperature of the thermal treatment performed on the green thin layer depending on the calcining material used. Taking costs into account, the thermal treatment is preferably performed in an air atmosphere or a reducing atmosphere at a temperature lower than about 1500° C. For example, when a(BaO)•Al 2 O 3 •b(SiO 2 ) (2≦a≦3 and 9≦b≦11) is used as the calcining material, the thermal treatment may be performed on the green thin layer in an air atmosphere at a temperature ranging from about 1000° C. to about 1300° C., and preferably ranging from about 1100° C. to about 1200° C.
[0033] In the fluorescent layer of the present invention, the calcining material replaces the conventional resin material and is used to package the fluorescent material, so the decreasing of luminous efficiency and aging (etiolation) of the resin layer can be prevented. Based on considerations for improving heat dissipation efficiency of the fluorescent layer or preventing crack of the fluorescent layer by heat stress, the fluorescent layer of the present invention may be applied in combination with a heat dissipation substrate.
[0034] Therefore, the present invention further provides a sapphire fluorescent plate. FIG. 2 shows a schematic drawing of a sapphire fluorescent plate according to one embodiment of the present invention. A sapphire fluorescent plate 100 comprises a sapphire substrate 2 and a fluorescent layer 1 on the sapphire substrate 2 .
[0035] A sapphire (aluminum oxide) thin plate is used as the substrate of the fluorescent plate of the present invention. The sapphire substrate has a heat conductivity coefficient of about 30 W/m·K to 40 W/m·K, and thus, can improve both the heat dissipation and light conversion of the applied light emitting device. Also, the sapphire substrate has a heat expansion coefficient of 5.8×10 −6 /K which is equal to a common diode material (for example, 5.8×10 −6 /K for a gallium nitride diode), and is more capable of preventing crack by heat stress during usage. Any commercial sapphire substrate may be used in the present invention. Taking costs into account, the thickness of the sapphire substrate is preferably about 0.2 mm to 2 mm, more preferably about 0.3 mm to about 0.6 mm.
[0036] In another aspect, the present invention also provides a method for manufacturing a sapphire fluorescent plate, comprising providing a sapphire substrate; providing a green thin layer using the steps in the method for manufacturing the fluorescent layer as described above; and placing the green thin layer on the sapphire substrate and performing a thermal treatment on the green thin layer and the sapphire substrate, wherein the thermal treatment is performed at a temperature around the eutectic point of the calcining material.
[0037] The sapphire substrate used in the method of the present invention, as described above, preferably has a thickness ranging from about 0.2 mm to about 2 mm, and more preferably, ranging from about 0.3 mm to about 0.6 mm.
[0038] After providing the sapphire substrate and the green thin layer, a thermal treatment is performed to connect both components. The green thin layer is placed on the sapphire substrate and a thermal treatment is performed on the green thin layer and the sapphire substrate at a temperature around the eutectic point of the calcining material to melt the partial surface of green thin layer and to connect the green thin layer with the sapphire substrate. The thermal treatment temperature generally depends on the calcining material. Taking costs into account, the thermal treatment is preferably performed in an air atmosphere or a reducing atmosphere at a temperature lower than about 1500° C. For example, in the case using a(BaO)•Al 2 O 3 •b(SiO 2 ) (2≦a≦3 and 9≦b≦11) as the calcining material, the thermal treatment on the sapphire substrate and the green thin layer may be performed in an air atmosphere at a temperature ranging from about 1000° C. to about 1300° C., and preferably at a temperature ranging from about 1200° C. to about 1300° C.
[0039] The present invention also provides a light emitting device, comprising an excitation light source, and a fluorescent layer or a sapphire fluorescent plate as described above. FIG. 3 is a schematic drawing of a light emitting device 200 according to one embodiment of the present invention, wherein an excitation light source 5 is connected with a fluorescent layer 1 . FIG. 4 is a schematic drawing of a light emitting device 201 according to another embodiment of the present invention, wherein an excitation light source 5 is connected with a sapphire fluorescent plate 100 .
[0040] In the light emitting device of the present invention, the wavelength of the light emitted from the excitation light source should be coordinated with the fluorescent material in the fluorescent layer; namely, the wavelength of the light emitted from the excitation light source should be capable of exciting the fluorescent material in the fluorescent layer, and the light emitted from the excitation light source can be mixed with a fluorescence emitted by the excited fluorescent material to become white light. The excitation light source is preferred to be blue light or an ultraviolet emitting diode (including a laser diode), which can excite most of the fluorescent materials. For example, a blue light excitation light source in combination with a YAG fluorescent material-containing fluorescent layer can emit white light, and an ultraviolet emitting diode may be in combination with a sapphire fluorescent plate containing a plurality of fluorescent materials to obtain white light.
[0041] According to the light emitting device of the present invention, the way of connecting the excitation light source and the fluorescent layer/sapphire fluorescent layer is not particularly limited, as long as the connection between the excitation light source and the fluorescent layer/sapphire fluorescent layer is firmly stable. For example, an adhesive may be used to bind the excitation light source on the fluorescent layer/sapphire substrate. The adhesive useful the present invention is normally selected from a transparent resin adhesive comprising, for example, an epoxy resin and a polyamide resin, and preferably, is used together with a diamond powder, aluminum nitride powder, aluminum oxide powder, or any combinations thereof Alternatively, the fluorescent layer/sapphire substrate may be fixed on the excitation light source in a manner of laminating (e.g., a fastener). In addition to the ways listed above, persons with ordinary skills in the art may adopt an appropriate connecting way as needed in practice after reviewing the context herein.
[0042] In still another embodiment of the present invention, the excitation light source in the light emitting device may be connected with a substrate with high heat conductivity to improve the heat dissipation of the light emitting device. The substrate with high heat conductivity is generally composed of a metal material, preferably, copper, aluminum or copper-aluminum alloy due to their excellent heat dissipation efficiency.
[0043] The present invention is further illustrated with the following examples. The following examples are intended for illustration only, but not to limit the scope of the present invention.
EXAMPLE
[Preparation of a Fluorescent Layer]
[0044] BaCO 3 , Al 2 O 3 and SiO 2 were weighed in a molar ratio of 2.5:1:10 and were wet milled using aluminum oxide balls for 30 minutes, and then, the obtained milled slurry was dried to obtain a precursor mixture of a calcining material. Next, a thermal treatment on the precursor mixture was performed at about 850° C. for about 4 hours to obtain a calcining material 2.5(BaO)•Al 2 O 3 •10(SiO 2 ).
[0045] Y 2.93 Al 5 O 12 :Ce 0.07 and the obtained calcining material 2.5(BaO)•Al 2 O 3 •10(SiO 2 ) were weighed in a weight ratio of 40:60, ground and mixed with each other. Then, the mixture was pressed to form a green thin layer with a thickness of about 1 mm via dry pressing.
[0046] A thermal treatment was performed on the obtained green thin layer in an air atmosphere at about 1140° C. for about 2 hours to obtain a fluorescent layer F with a thickness of about 0.8 mm, as shown in FIG. 1 .
[Preparation of a Sapphire Fluorescent Plate]
[0047] BaCO 3 , Al 2 O 3 and SiO 2 were weighed in a molar ratio of 2.5:1:10 and wet milled using aluminum oxide balls for 30 minutes, and then, the obtained milled slurry was dried to obtain a precursor mixture of a calcining material. Next, a thermal treatment on the precursor mixture was performed at about 850° C. for about 4 hours to obtain a calcining material 2.5(BaO)•Al 2 O 3 •10(SiO 2 ).
[0048] Y 2.93 Al 5 O 12 :Ce 0.07 and the obtained calcining material 2.5(BaO)•Al 2 O 3 •10(SiO 2 ) were weighed in a weight ratio of 36:64, ground and mixed with each other. Then, the mixture was pressed to form a green thin layer with a thickness of about 1 mm via dry pressing.
[0049] The obtained green thin layer was placed on a sapphire substrate with a thickness of 0.425 mm, and a thermal treatment was performed on the green thin layer and the sapphire substrate in an air atmosphere at about 1250° C. for about 2 hours to obtain a sapphire fluorescent plate A with a fluorescent layer that has a thickness of about 0.8 mm, as shown in FIG. 2 .
[Preparation of a Light Emitting Device]
[0050] *Light emitting device I*
[0051] The sapphire fluorescent plate A was fixed on a blue light LED (gallium nitride diode) to obtain a light emitting device I, as shown in FIG. 4 .
[0052] A UV-visible-nearIR spectrum analyzer (Model PMS-80, EVERFINE Co., Ltd., Hangzhou, China) was used to test the luminescence spectrum of the light emitting device I under a 3 V voltage and 0.2 A current. The result is shown in FIG. 5 . It can be seen from FIG. 5 that the luminescence spectrum of the light emitting device I mainly consists of a narrow peak of wavelength of about 460 nm (blue light) and a broad peak of wavelength of about 560 nm (yellow light). The mixing result of the light emitting device I was obtained by transforming the results in FIG. 5 to Commission Internationale de i'Eclairage (CIE) coordinate diagram (see FIG. 6 ), obtaining a white light at x=0.3065 and y=0.3352. It is therefore shown that the sapphire fluorescent plate of the present invention can replace the traditional fluorescent material package and obtain white light.
[0053] The above examples are used to illustrate the principle and efficacy of the present invention and show the inventive features thereof People skilled in this field may proceed with a variety of modifications and replacements based on the disclosures and suggestions of the invention as described without departing from the principle and spirit thereof Therefore, the scope of protection of the present invention is that as defined in the claims as appended. | A fluorescent layer, its preparation method and uses are provided. The fluorescent layer is provided from a fluorescent material and a calcining material. The fluorescent material is in an amount ranging from about 5 wt % to about 95 wt % based on the total weight of the fluorescent layer. The fluorescent layer of the present invention can be used in a light-emitting diode to change the color of emitting-light and improve the heat dissipation of the light-emitting diode. Furthermore, the fluorescent layer of the present invention is free of an organic resin, and thus, does not have the problem of aging (etiolation). The final product has a stable, lasting and durable luminescent quality. | 2 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to durable-press fabrics. More specifically, it relates to a catalyst system that is useful in the treatment of cellulose-containing textile materials with certain formaldehyde-amide adduct finishing agents to give valuable durable-press properties in the textile product
2. Description of the Prior Art
Synergistic catalyst effects are produced when aluminum chlorhydroxide, hereinafter referred to as Al 2 (OH) 5 Cl, is used with certain salts or with certain acids. Stronger catalysis results from the use of a combination of such salts or acids and Al 2 (OH) 5 Cl than from the use of either component alone. Reinhardt et al., U.S. Pat. No. 3,909,861, have amply demonstrated the uses of Al 2 (OH) 5 Cl with various salts and acids. They have also pointed out that some known latent acidic catalysts, such as Mg(H 2 PO 4 ) 2 , and alkaline salts are ineffective in combination with Al 2 (OH) 5 Cl. These workers demonstrated a buffering effect with strong acids and an activating effect with weak acids by use of Al 2 (OH) 5 Cl. They also demonstrated the effectiveness of Al 2 (OH) 5 Cl alone as catalyst in treatments by the conventional pad-dry-cure process at temperatures of 140° to 180° C.
Reinhardt et al., American Dyestuff Reporter 64 (May 1975), discuss Al 2 (OH) 5 Cl catalyst systems in the specialized techniques of moist curing and steam curing and show effective curing temperatures of from 100° to 180° C. In pad-dry-cure finishing, Al 2 (OH) 5 Cl compares favorably with MgCl 2 , ZnCl 2 , and Zn(NO 3 ) 2 as a catalyst. These workers, in general, teach away from curing at highly elevated temperatures when mixed catalyst systems containing Al 2 (OH) 5 Cl are used.
Very little information is available in the literature concerning H 2 O 2 as a catalyst for the reaction of finishing agents used in treatment of cellulose-containing textiles to obtain wash-wear, wrinkle resistance or durable-press properties. Gagliardi, American Dyestuff Reporter 40 (November 1951) lists H 2 O 2 as one of five types of catalyst for resin finishing of fabric. He suggests that, in aqueous solutions containing free formaldehyde, H 2 O 2 will oxidize the formaldehyde to formic acid which then catalyzes the reaction of the resin with cloth. Gagliardi states that this catalyst has not been exploited commercially; the delayed formation of formic acid from free formaldehyde is one major factor hindering such exploitation. Although Gagliardi mentions H 2 O 2 as a catalyst no data or treatment details are presented. Apparently, very specialized conditions must be employed to obtain effective catalysis.
British Pat. No. 482,254 discloses H 2 O 2 as a catalyst for the condensation product of urea and formaldehyde. Of particular note in the teachings of this patent is the highly restrictive method required to make the process operative. Once fabric has been impregnated with H 2 O 2 and a water-soluble condensation product obtained from formaldehyde and urea, or similar amines or amides, it is necessary to quickly heat the wet, impregnated textile to the critical temperature range of 95°-100° C. This highly selective step is required to achieve further resin condensation in the cloth material.
In all prior work, no catalyst system has been employed that is composed of Al 2 (OH) 5 Cl and an oxidizing agent such as H 2 O 2 . Those systems with Al 2 (OH) 5 Cl and another component all teach away from the conventional curing temperatures employed in the pad-dry-cure process. One skilled in the teachings of the prior art would not anticipate effectiveness of H 2 O 2 as a catalyst in textile finishing unless conversion of free formaldehyde to formic acid is promoted either in the treatment bath or in the impregnated fabric.
SUMMARY OF THE INVENTION
This invention provides a catalyst system consisting of Al 2 (OH) 5 Cl and H 2 O 2 which is operative at high curing temperatures for very short curing times or at curing temperatures down to 130° C. with longer curing times in treatments of cellulose-containing textiles with formaldehyde-amide adduct finishing agents to produce durable-press products. Short curing times at high temperatures, called flash curing, are employed with the use of selected crosslinking agents and the catalyst system. Among suitable finishing agents are dimethylol dihydroxyethyleneurea and dimethylol methyl carbamate. Treatment is accomplished by padding the fabric with the treatment solution, drying the fabric to remove most of the moisture, then curing the fabric.
It is thus an object of this invention to produce cellulose-containing fabrics with excellent durable-press appearance.
It is a further object to provide an improved catalyst system that is efficient and practical for use in treatments for finishing cellulose-containing textiles with certain formaldehyde-amide adduct agents.
A still further object is to furnish a catalyst system consisting of Al 2 (OH) 5 Cl and H 2 O 2 that will provide effective and efficient catalysis on flash curing as well as in conventional pad-dry-cure finishing.
The objects of this invention are achieved by use of the catalyst system based upon Al 2 (OH) 5 Cl and H 2 O 2 in treatments for cellulose-containing textiles with formaldehyde-amide adduct finishing agents. The specific combination of the Al 2 (OH) 5 Cl and H 2 O 2 provides efficient, rapid catalysis in flash cure processing.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
We have found that a catalyst system consisting of Al 2 (OH) 5 Cl and H 2 O 2 is highly efficient in treatments for producing durable-press fabric but with little apparent formation of formic acid in the process. This is particularly noteworthy as anyone skilled in the art would avoid formation of a strong acid on the fabric at elevated temperatures because of the well-known deleterious effect of the hydrolytic action of strong acids on textile properties. The catalyst system consisting of Al 2 (OH) 5 Cl and H 2 O 2 is effective at curing temperatures up to about 200° C. A rapid, high temperature cure, hereinafter referred to as flash curing, can be accomplished at 200° C. in 10 seconds.
The catalyst system of the present invention offers the textile finisher the ability to achieve certain treatments under processing conditions previously found impossible or impractical to employ.
The catalyst system is composed of Al 2 (OH) 5 Cl and H 2 O 2 . Concentrations of Al 2 (OH) 5 Cl that may be used are from about 2 millimoles to about 10 millimoles for each 100 g. of treatment bath. Expressed alternatively, these concentrations are about from 0.35% to 1.75%, by weight, of the treatment bath. Hydrogen peroxide concentrations employed should be such that the molar ratio of Al 2 (OH) 5 Cl to H 2 O 2 is in the range of from about 1:4 to about 1:0.25. The preferred molar ratio of Al 2 (OH) 5 Cl to H 2 O 2 is about 1:1; preferred concentrations are about 5 millimoles of each in 100 g. of treatment bath (or about 0.87% Al 2 (OH) 5 Cl and 0.17% H 2 O 2 , by weight).
Formaldehyde-amide adduct crosslinking agents, selected from the group consisting of dimethylol dihydroxyethyleneurea, dimethylol ethyleneurea, dimethylol alkyl carbamates, dimethylol alkoxyalkyl carbamates, dimethylol hydroxyalkyl carbamates, and the esterified and etherified N-methylol derivatives thereof such as acetoxymethyl alkyl carbamates and methoxymethyl ethleneurea and the like, may be used in concentrations ranging from about 7% to about 20%, by weight, of the treatment bath.
Temperatures to achieve flash curing range from about 175° C. to about 215° C. with the preferred temperature being about 200° C. Times for flash curing may be from about 10 seconds to about 45 seconds, the preferred flash curing conditions are 20 seconds at 200° C. With suitable adjustment of processing time, lower curing temperatures, i.e., in the more conventional range of 120°-175° C., also may be employed. For example, curing at 130° C. for 3 minutes can be effectively employed with the catalyst system of this invention.
The cellulose-containing material may contain 50% or more cellulose and may be in the form of fibers, yarns, or fabrics. Fabric is the most suitable form for treatment to achieve durable-press properties.
The following examples further describe the invention. They are given as illustrations and thus should not be considered as limiting the scope of the invention. In the examples, durable-press (DP) ratings, tumble dried (TD) were determined according to the test procedure described in AATCC 124-1969, III-B.
EXAMPLE 1
Aqueous solutions were prepared such that in each 100 g. there were 9 g. of dimethylol dihydroxyethyleneurea, 5 millimoles of Al 2 (OH) 5 Cl, and 5 millimoles of H 2 O 2 with:
Sample A--no free formaldehyde (FF) added;
Sample B--with 0.2% FF added;
Sample C--with 0.4% FF added;
Sample D--with 0.6% FF added; and
Sample E--with 0.8% FF added.
A 3.2 oz/sq. yd. cotton printcloth fabric was used for treatments. Samples were impregnated with these solutions and squeezed through pad rolls to achieve approximately 80% (by weight) wet pick-up of the treatment solution. The wet, impregnated samples were pinned on frames, then dried for 7 minutes at 60° C. and cured for 3 minutes at 140° C. Samples were then washed, tumble dried and rated for durable-press (DP) appearance.
Results are given in Table I.
TABLE I______________________________________Sample A B C D E______________________________________%FF added to treatment 0 0.2 0.4 0.6 0.8 bathDP rating after tumble 3.3 3.3 3.3 3.3 3.3 drying______________________________________
This demonstrates that addition of free formaldehyde to the treatment bath containing H 2 O 2 has no influence on improvement of durable-press appearance.
EXAMPLE 2
Aqueous solutions were prepared such that in each 100 g. there were 9 g. of dimethylol dihydroxyethyleneurea and:
Sample F--5 millimoles of Al 2 (OH) 5 Cl and 5 millimoles of HCOOH;
Sample G--10 millimoles of Al 2 (OH) 5 Cl;
Sample H--5 millimoles of HCOOH; and
Sample I--10 millimoles of HCOOH.
A 3.2 oz/sq. yd. cotton printcloth fabric was used for the treatments. Samples were impregnated with these solutions and squeezed through pad rolls to achieve wet pick-ups of approximately 80% (by weight) of the treatment solution. The wet, impregnated fabrics were pinned on frames then dried for 7 minutes at 60° C. and cured for 3 minutes at 160° C. After curing, samples were washed, dried, and rated as in Example 1.
Results are given in Table II.
TABLE II______________________________________Sample F G H I______________________________________DP rating 4.3 4.3 1.7 2.4______________________________________
No synergistic catalytic effect was obtained by adding HCOOH to Al 2 (OH) 5 Cl as seen by comparing DP ratings of Samples F. and G. Further, it is demonstrated that HCOOH is not a satisfactory catalyst in developing suitable DP performance in the treatment of fabric with DMDHEU, see Samples H and I.
EXAMPLE 3
The use of the Al 2 (OH) 5 Cl/H 2 O 2 catalyst system in finishing cotton fabric by the pad-dry-cure method with dimethylol methyl carbamate is illustrated by the data of Table III. The synergistic interaction of the catalyst components at both the 130° C. and 160° C. curing temperatures should be noted.
TABLE III__________________________________________________________________________Catalystconcentration.sup.1/ mmol Al.sub.2 (OH).sub.5 Cl 10 7.5 5 2.5 0 mmol H.sub.2 O.sub. 2 0 2.5 5 2.5 10__________________________________________________________________________Curing temperature, 130 160 130 160 130 160 130 160 130 160 ° C.DP rating 2.6 3.4 3.3 3.5 3.2 3.7 3.2 3.9 1.0 1.6__________________________________________________________________________ .sup.1/ Cotton printcloth impregnated with a solution containing 10% dimethylol methyl carbamate and the indicated concentrations of Al.sub.2 (OH).sub.5 Cl and H.sub.2 O.sub.2 (millimoles/100 g. solution), dried for 7 min. at 60° C., cured for 3 min. at the indicated temperature, washed, and tumble dried.
EXAMPLE 4
The use of Al 2 (OH) 5 Cl, Al 2 (OH) 5 Cl/H 2 O 2 , and H 2 O 2 catalyst systems with dimethylol methyl carbamate in finishing a cotton printcloth and a 50/50 cotton/polyester percale sheeting at various times in flash curing is illustrated in Table IV.
TABLE IV______________________________________Millimoles catalyst/100 g. Curebath .sup.1/ time, DP rating (TD)[Al.sub.2 (OH).sub.5 Cl/H.sub.2 O.sub.2] seconds Printcloth Sheeting______________________________________10/0 5 1.5 3.310/0 10 2.9 3.310/0 20 3.0 3.710/0 30 3.3 3.95/5 5 2.7 3.35/5 10 3.3 4.25/5 20 3.7 4.55/5 30 4.0 4.50/10 5 1.3 2.70/10 10 1.4 3.00/10 20 1.4 3.00/10 30 1.5 3.2______________________________________ .sup.1/ Fabric impregnated with a solution containing 10% dimethylol methyl carbamate and the indicated concentration of Al.sub.2 (OH).sub.5 C and H.sub.2 O.sub.2, dried for 7 min. at 60° C., flash cured at 200° C., washed and dried.
The superior catalytic action afforded through the synergistic effect of the catalyst mixture should be particularly noted.
EXAMPLE 5
The use of the Al 2 (OH) 5 Cl/H 2 O 2 catalyst system in finishing cotton printcloth and a 50/50 cotton/polyester percale sheeting with dimethylol methyl carbamate by flash curing is illustrated in Table V. Improvement in durable-press appearance is achieved with concentrations of Al 2 (OH) 5 Cl and H 2 O 2 as low as 2.5 millimoles of each per 100 g. of treatment bath.
TABLE V______________________________________Mmol Al.sub.2 (OH).sub.5 Cl 2.5 5.0 7.5 10Mmol H.sub.2 O.sub. 2 2.5 5.0 7.5 10DP rating(TD) Printcloth .sup.1/ 3.3 3.3 4.0 4.3 Sheeting 3.7 4.3 4.0 4.5______________________________________ .sup.1/ Fabric impregnated with a solution of 10% dimethylol methyl carbamate and the indicated concentration of catalyst per 100 g. of bath, dried for 7 min. at 60° C., cured for 15 seconds at 200° C. washed, and tumble dried.
EXAMPLE 6
Catalyst systems incorporating the oxidizing agents, K 2 S 2 O 8 or (NH 4 ) 2 S 2 O 8 , and Al 2 (OH) 5 Cl with dimethylol methyl carbamate in finishing a cotton printcloth resulted in fabric discoloration as seen in Table VI.
TABLE VI______________________________________Millimolescatalyst/100 g. bath.sup.1/ DP rating Coloration______________________________________Al.sub.2 (OH).sub.5 Cl/K.sub.2 S.sub.2 O.sub.8 3.5 Very light (5/5) yellowAl.sub.2 (OH).sub.5 Cl/(NH.sub.4).sub.2 S.sub.2 O.sub.8 4.3 Light (5/5) yellow______________________________________ .sup.1/ Fabric impregnated with a solution containing 10% dimethylol methyl carbamate and the indicated catalyst, dried for 7 min. at 60° C., flash cured 15 seconds at 200° C., washed and tumbl dried.
This demonstrates that oxidizing agents other than H 2 O 2 are not suitable in flash curing for producing durable-press fabrics without fabric discoloration. | A catalyst system composed of aluminum chlorhydroxide [Al 2 (OH) 5 Cl] and hydrogen peroxide [H 2 O 2 ] is disclosed which through synergistic interaction of these components is highly efficient and effective in treatments of cellulose-containing textiles with formaldehyde-amide adduct crosslinking agents. Products with durable-press properties are produced through use of the new catalyst system in treatments employing flash curing conditions, i.e., short processing times at high temperatures, as well as in treatments employing curing temperatures down to 130° C. with longer processing times. Unlike previously known synergistically activated catalyst systems based upon Al 2 (OH) 5 Cl, the presently disclosed system utilizes the combination of Al 2 (OH) 5 Cl with H 2 O 2 , an oxidizing agent, rather than with an acid or a salt with latent acidic or Lewis acid properties. | 3 |
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